Review Special Issues

Chromatin dynamics at DNA breaks: what, how and why?

  • Received: 15 July 2015 Accepted: 06 September 2015 Published: 10 September 2015
  • Chromatin has a complex, dynamic architecture in the interphase nucleus, which regulates the accessibility of the underlying DNA and plays a key regulatory role in all the cellular functions using DNA as a template, such as replication, transcription or DNA damage repair. Here, we review the recent progresses in the understanding of the interplay between chromatin architecture and DNA repair mechanisms. Several reports based on live cell fluorescence imaging show that the activation of the DNA repair machinery is associated with major changes in the compaction state and the mobility of chromatin. We discuss the functional consequences of these changes in yeast and mammals in the light of the different repair pathways utilized by these organisms. In the final section of this review, we show how future developments in high-resolution light microscopy and chromatin modelling by polymer physics should contribute to a better understanding of the relationship between the structural changes in chromatin and the activity of the repair processes.

    Citation: Théo Lebeaupin, Hafida Sellou, Gyula Timinszky, Sébastien Huet. Chromatin dynamics at DNA breaks: what, how and why?[J]. AIMS Biophysics, 2015, 2(4): 458-475. doi: 10.3934/biophy.2015.4.458

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    The prevalence of non-communicable diseases diabetes is increasing at an alarming rate. In 2015, it was predicted that 422 million individuals would develop diabetes mellitus (DM) [1]. By 2035, it is expected that this figure will double [1]. The incidence of diabetes on a global scale is a serious public health issue; it has either caused or aggravated numerous clinical conditions, such as hypertension, heart disease, excessive cholesterol, cancer, and dementia [2].

    The need to discover new antimicrobial compounds is being increasingly recognized in this age of antibiotic resistance [3]. There is a growing need for novel chemicals with direct antibacterial or indirect action that enhances the resistance mechanism of microorganisms, since infectious illnesses continue to be a major public health concern. Plants' natural products are crucial to the search for new therapeutic medicines [4].

    Plants are employed either directly or indirectly in the composition of 25% of today's medications, many of which are made from medicinal plants [4]. In recent years, the potential for the treatment of numerous diseases with medicinal plants has been a growing [5]. The treatment of diseases from plant products are risk free, less toxic, and inexpensive [6].

    Natural products obtained from plants are known to be alternative forms of medicine and have gained a lot of attention. For improvement of health statuses and the treatment of diverse ailments, a great percentage of people all over the world rely on natural products derived from plant parts [7]. As a medical substance, medicinal plants play an essential role in pharmacological research, disease treatment and prevention, and as raw materials for the creation of pharmacologically active products [8].

    Pharmacokinetic variables are increasingly being incorporated into drug discovery procedures using computer-based methodologies [9]. A chemical with both a high potency and a favorable chemical absorption, distribution, metabolism, excretion, and toxicity (ADMET) profile is considered a potential lead compound. Therefore, regardless of their great potency, drugs with unimpressive projected ADMET profiles can be quickly removed from the pool of potential therapeutic candidates [10]. The use of computational approaches in medical synthetic chemistry has become commonplace; however, its application in the study of natural chemicals has not received enough attention.

    There are 131 genera and about 5500 species in the Myrtaceae family, all of which are woody trees or shrubs and have essential oils [11]. Several family members are commercially well-known for their therapeutic essential oils [11]. E. camaldulensis, which is a species of the Myrtaceae family, is commonly used to treat stomach ailments in Nigeria.

    Moreover, a decoction made from the leaves is claimed to be effective against urinary tract infections, respiratory tract infections, and sore throats caused by bacteria. A poultice produced from the leaves is used to treat wounds and sores [12]. The anti-tubercular effect of the essential oils extracted from the leaves has led to their usage in the treatment of lung ailments [12]. With its infusions, one can treat gastrointestinal problems, respiratory problems, halt bleeding, heal cuts and open wounds, and relieve aches and pains in the muscles, joints, and teeth [13]. Bacterial infections and inflammatory-related disorders are traditionally cured with an extract made from the leaves [14]. The plant is extensively utilized in traditional treatments for colds, asthma, diarrhea, dysentery, laryngitis, and sore throats [15]. Previously, there was antimicrobial investigation on E. camaldulensis [12],[16],[17]. Antibiotic-resistant diseases cost approximately up to $29,069 per patient and can lead to an extended length of treatment. Therefore, there is a need to find cutting-edge, natural, antimicrobial drugs and treatments [14].

    The aim of this study is to use various in vitro biological models in combination with in silico analysis to enhance the current literature. This involves assessing the antioxidant, anti-diabetic, and antibacterial properties alongside specific in silico methods to predict the drug-likeness, pharmacokinetic behavior, and binding effectiveness of the identified phytochemicals extracted from E. camaldulensis leaves.

    E. camaldulensis leaves samples (Figure 1) were gathered from outdoor areas, field gardens, and backyard gardens; subsequently, herbarium specimens were made. After the verification of the plant's identity by a qualified taxonomist, the plants were donated to the Ahmadu Bello University Herbarium in Zaria with the following assign voucher number: ABU02510. The World Flora Online (WFO) https://www.worldfloraonline.org/ was utilized to authenticate the species name.

    Figure 1.  The leaves of Eucalyptus camaldulensis Dehnh.

    The leaves were washed under running water to get rid of any remaining dirt, stains, or latex. A grinding machine was employed to pulverize the dehydrated samples into a fine powder. The powdered plant samples were quantified by weighing 100 g of the sample. The Soxhlet technique was used to extract ethanol and an aqueous layer from the plant leaves.

    A Whitman No. 1 filter was used to filter the extraction's result. Both the ethanol and aqueous plant leaf samples were crudely extracted using the E-Z-2-Elite evaporation apparatus. For the ethanol and aqueous extracts, the solvent pressure was set to 72 and 300, respectively, and the vacuum was set to 40 °C [18]. The extracts were dried in a refrigerated vacuum oven at 40 °C until they reached a uniform mass, after which they were concentrated with a rotary evaporator and weighed with an electronic balance [19]. The weight of the crude yield is derived by the following simple calculation: Yield % = Extraction yield (%) = F1/F2 × 100, where F1 is the mass of the crude extract and F2 is the mass of the sample [20].

    Freshly cut E. camaldulensis leaves were extracted in a Clevenger device under reflux for 4 hours. Then, the resulting essential oil (EO) was extracted with dichloromethane, the organic phase was separated and dried with anhydrous sodium sulphate, filtered, and stored in an airtight flask at a low temperature (−10 °C) [21]. This method was carried out in triplicate and the percent yield was computed in relation to the dried mass of the initial sample.

    Seven different concentrations of ethanol, aqueous, and EO of the leaves were subjected to a 100 g mL−1 (0.004% w/v) DPPH methanol solution to determine its effect. For 30 minutes, the solution was allowed to sit undisturbed at room temperature and without light. Comparisons were made using quercetin as a standard [22]. The calculation for the radical scavenging activity is as follows:

    % Inhibition = [(Bo − B1)/Bo)] × 100

    where B1 is the sample absorbance (517 nm) and Bo is the control absorbance (517 nm) reaction.

    A mixture of acetate buffer (B, 300 mM), 2,4,6-tri (2-pyridyl) -S-triazine (TPTZ, 10 mM) in HCl (40 mM), and iron chloride (FeCl3, 20 mM) were heated in a water bath for 10 minutes at 37 degrees Celsius. Following a 30-minute incubation at room temperature in the dark, 285 L of a FRAP working solution (100 µg/g mL concentrations) was added to 15 µL of ethanol, aqueous, or EO (100%) extracts of the leaf samples [22].

    50 µL of 0.1 M phosphate buffer (pH 7.0) was combined with 10 µL of the ethanol, aqueous, or EO extracts of the leaves at 100 µg/mL. 25 L of α-glucosidase (Sigma Aldrich) in buffer (0.2 U/mL) was placed onto a well plate to initiate the reaction. A 25 µL sample of 0.5 mM 4-nitrophenyl alpha-Dglucopyranoside (pNPG) substrate was added to complete the reaction, which was then incubated for an additional 30 minutes at 37 °C [23]. The process was stopped by introducing 100 µL of a 0.2 M sodium carbonate solution. Acarbose at 100 µg/mL was used as a positive control. The absorbance was determined at 410 nm. The percent inhibition was calculated using the following formula:

    Inhibition (%) = [Control abs – sample abs)/control abs] × 100

    Gram-positive Pseudomonas aeruginosa and Gram-negative Staphylococcus aureus bacteria were provided by the biology department of Tishk International University. Mueller Hinton agar plates were streaked with the microbial stock cultures using an inoculation loop, and then the plates were incubated at 37 °C overnight. The following day, they were subcultured again until a new colony was established. After that, they were injected with Mueller Hinton broth and allowed to incubate at 200 rpm overnight [24].

    Microbial inoculums containing 1.106 (CFU)/mL were seeded onto 200 µL solidified Mueller-Hinson plates. The plant component (ethanolic, aqueous, and EO) extracts were impregnated with 20 µL of 4000 µg/mL on Whatman No. 1 filter paper discs (6 mm). Using sterile forceps, the impregnated disk was positioned on the plates. The plates were incubated at 37 °C for 24 hours [24].

    Components of the EOs were analysed by means of gas chromatography linked to mass spectrometry (GC-MS, Shimadzu/QP2010) with an OV-5 bonded capillary column (30 m 0.25 mm 0.25 m film thickness). The propellant gas was helium, and the flow rate was 1 mL/min. Temperatures of 220 and 240 °C were reached in the injector and detector, respectively. 1.0 µL was injected at a split ratio of 1: 20. The oven temperature was set to gradually increase from 60 °C to 240 °C at a rate of 3 °C/min with 1 min hold. The collected pieces had velocities ranging from 40 to 650 m/z and an electron impact energy of 70 eV [21].

    The experiments were performed in a completely randomized manner, with three replicates of each treatment, and the statistical analyses were performed using the Statistical Analysis System (SAS) for data analysis (University version 9.4). After performing a one-way repeated-measures analysis of variance (ANOVA) [25], a post-hoc test, namely Duncan's multiple range test, was employed to evaluate if there were any statistically significant differences between the group means at the p ≤ 0.05 level.

    Antidiabetic properties of the phytochemicals isolated from E. camaldulensis were investigated in a docking study against the α-glucosidase enzyme (Protein Data Bank (PDB): 3A4A). The selection of the 3A4A PDB structure was made considering several factors, including its crystallization with an inhibitor to compare with docked ligands, a resolution of less than 2 Å, and the absence of mutations. The protein was obtained and downloaded as a PDB file from the following: https://www.rcsb.org/. Chimera software tools [26] were used to remove the native ligand present in the PDB structure of the protein.

    The 1D structures of the isolated phytochemicals and the four controls including the native inhibitor, alpha-D-glucopyranose, were retrieved from the PubChem Search database as strings of canonical smiles. To facilitate the analysis, the smile sequences were converted into 3D PDB files using a web server known as CORINA, https://demos.mn-am.com/corina.html.

    The CB-Dock server automatically optimizes the ligand input files as reported by [27]. CB-Dock is a docking tool for protein-ligand interactions that automatically detects the binding sites, determines their center and size, adjusts the docking box dimensions based on the query ligands, and subsequently conducts molecular docking using the AutoDock Vina software, v1.2.5 [28]. The docking process consists of three steps: Search Cavities, View Results, and BlindDock. The active site parameters for docking included a Cavity Volume of 2996 Å3, with the center coordinates of X = 15, Y = −14, and Z = 16. The generated poses were evaluated and visualized using the CB-Dock server and Chimaera software tools.

    The inhibition constant (Ki) was calculated using the following formula: Ki = exp(ΔG/RT), where ΔG is the binding energy, R is the universal gas constant (1.985 × 10−3 kcal mol−1 K−1), and T is the temperature (298.15 K).

    A molecular dynamics (MD) simulation was performed using the CABS Flex 2.0 server [29] for α-glucosidase (without ligands) and α-glucosidase-5.alpha.-androstan-16-one complex to calculate the root mean square fluctuation (RMSF) values. The parameters used were as follows: Time, 10 ns; Mode, SS2; Interval, 3; Global weight, 1.0; Number of cycles, 50; Cycles between trajectory frames, 50; Simulation temperature, 1.4; and Random number generator seed, 5546.

    The SMILES strings of the 5.alpha.-Androstan-16-one compound were obtained from PubChem (http://pubchem.ncbi.nlm.nih.gov/). Next, we calculated the drug-likeness parameters of the analyzed compound using the SwissADME online webserver (http://www.swissadme.ch/index.php). The bioactivity score for an enzyme inhibitor was determined through the utilization of the Molinspiration server located at http://www.molinspiration.com/cgi-bin/properties. The prediction of hepatotoxicity toxicity was conducted using pkCSM, which is a server that predicts the toxicity of small molecules, https://biosig.lab.uq.edu.au/pkcsm/prediction.

    The aqueous extract of Eucalyptus camaldulensis leaves had a greater yield of 0.87% compared to the ethanol extract and EO, which had yields of 0.65% and 0.48%, respectively (Figure 2).

    Figure 2.  Extraction yield of ethanol, aqueous and essential oil.

    Table 1 displays the inhibitory effects of the ethanol, aqueous, and EO extracts of E. camaldulensis leaves using the DPPH radical scavenging method. The highest inhibition was recorded from the EO at 84 % (Table 1 and Figure 3). The highest capacity to convert Fe3+ to Fe2+ was noted for the aqueous leaves extract, even when compared to the standard used (Figure 4). The result exhibits a significant difference among the examined treatments. The principal enzyme in charge of catalysing the final stage of carbohydrate digestion is α-glucosidase. The highest level of α-glucosidase activity for the leaf EO was reported to have an inhibitory value of 78 % (Table 1). The tested extract demonstrated a substantial zone of inhibition against the tested strains of Staphylococcus aureus and Pseudomonas aeruginosa. The EO exhibited the highest zone of inhibition at 12 mm and 14 mm for Staphylococcus aureus and Pseudomonas aeruginosa, respectively. These values were greater than the zone of inhibition observed for ampicillin at 9 mm and 6 mm for S. aureus and P. aeruginosa, respectively (Figure 5). A statistically significant difference was found between the treatments at p ≤ 0.05. Due to the significant activity of the EO, it underwent further examination of its chemical makeup using GCMS.

    Table 1.  Antioxidant, α-glucosidase and antimicrobial activities of E. camaldulensis leaves.
    S/N Plant part/extract % of inhibition of DPPH FRAP Fe2+/(mmol/g) % of inhibition of α-glucosidase Zone of inhibition Staphylococcus aureus (mm) Zone of inhibition Pseudomonas aeruginosa (mm)
    1 Ethanolic Leaves 75.1 ± 1.0b 12.9 ± 2c 60 ± 0.2c 10 b, c 8 b
    2 Aqueous Leaves 69.3 ± 03c,d 10.4 ± 4d 63 ± 1.0b 6 d 6 c, d
    3 Essential oil 84.01 ± 01a 20.1 ± 1a 78 ± 2.1a 12a 14 a
    4 Quercetin/Acarbose 70.04 ± 2.0c 15.8 ± 1b 54 ± 0.1d
    5 Ampicillin (10 µg) 9 c 6 d

    Note: The numbers represent the means and standard deviations of three separate experiments, each of which was carried out three times. Vertically similar alphabets do not statistically differ at the p ≤ 0.05 level.

     | Show Table
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    Figure 3.  Percentage of DPPH radical scavenging activities.
    Figure 4.  Bar graph of FRAP showing the extract capacity to convert Fe3+ to Fe2+.
    Figure 5.  Leaves essential oil activity against (A) Staphylococcus aureus and B Pseudomonas aeruginosa.

    Table 2 exhibits the spectra of the EOs identified components (mass spectrum of each compound of the EO are presented in Supplementary Table S2). The EO was broken down into its 42 constituent compounds with 99 .9 % of the EO (Figure 6). There was a dominance of cis-11-Hexadecenal (10.2%), trans-13-Octadecenoic acid (9.5%), and 6-Octadecenoic acid, methyl ester, (Z)- (8.8 %), with the rest having 7 to 0. 1 %, respectively (Table 2).

    Table 2.  Essential oil constituents of Eucalyptus camaldulensis.
    S/N RT Area Compound Molecular structure
    1 6.9295 0.5058 Furan, 2,5-dihydro-3-methyl-
    2 7.6833 1.4124 6-Tridecene, 7-methyl-
    3 8.1449 1.147 dl-Lysine
    4 8.4441 1.1377 3-Cyclohexylthiolane,S,S-dioxide
    5 8.6201 0.9649 1-Isopropoxy-2,2,3-trimethylaziridine
    6 8.7722 0.6063 Furan, 2,5-dihydro-3-methyl-
    7 8.8871 0.982 1H-Cyclopropa[a]naphthalene, 1a,2,3,5,6,7,7a,7b-octahydro-1,1,7,7a-tetramethyl-, [1aR-(1a.alpha.,7.alpha.,7a.alpha.,7b.alpha.)]-
    8 9.068 8.0481 Aromandendrene
    9 9.5046 4.099 Alloaromadendrene
    10 9.7889 1.7229 5.alpha.-Androstan-16-one
    11 10.329 2.5538 (1S,2E,6E,10R)-3,7,11,11-Tetramethylbicyclo[8.1.0]undeca-2,6-diene
    12 11.2245 0.3508 Dodecanoic acid, methyl ester
    13 11.8237 0.2395 1-Methylene-2b-hydroxymethyl-3,3-dimethyl-4b-(3-methylbut-2-enyl)-cyclohexane
    14 12.153 0.5436 1H-Cycloprop[e]azulen-7-ol, decahydro-1,1,7-trimethyl-4-methylene-, [1ar-(1a.alpha.,4a.alpha.,7.beta.,7a.beta.,7b.alpha.)]-
    15 12.3177 3.3133 Azulene, 1,2,3,3a,4,5,6,7-octahydro-1,4-dimethyl-7-(1-methylethenyl)-, [1R-(1.alpha.,3a.beta.,4.alpha.,7.beta.)]-
    16 12.6917 0.8741 Naphthalene, decahydro-4a-methyl-1-methylene-7-(1-methylethenyl)-, [4aR-(4a.alpha.,7.alpha.,8a.beta.)]-
    17 12.9604 0.2569 1-Tetradecene
    18 13.1784 1.1556 2-Naphthalenemethanol, 2,3,4,4a,5,6,7,8-octahydro-.alpha.,.alpha.,4a,8-tetramethyl-, [2R-(2.alpha.,4a.beta.,8.beta.)]-
    19 13.9033 1.1754 3-Tetradecanynoic acid
    20 14.1865 0.5571 Methyl 10-oxo-8-decenoate
    21 14.9428 0.1751 9-Hexadecenoic acid, octadecyl ester
    22 15.4386 2.6144 cis-Z-α-Bisabolene epoxide
    23 17.0159 0.604 Alpha-Phellandrene
    24 17.3444 0.1292 Gamma-Terpinene
    25 19.8713 1.4356 13-Octadecenal, (Z)-
    26 20.0676 1.31 1,2-Benzenedicarboxylic acid, butyl 2-ethylhexyl ester
    27 21.5497 1.3177 l-(+)-Ascorbic acid 2,6-dihexadecanoate
    28 21.9975 1.6346 7-Hexadecenal, (Z)-
    29 22.9324 7.7147 9,12-Octadecadienoic acid, methyl ester
    30 23.0931 8.8599 6-Octadecenoic acid, methyl ester, (Z)-
    31 23.4822 3.9623 9-Hexadecenoic acid
    32 23.6908 1.2546 Methyl stearate
    33 24.342 1.8422 1,19-Eicosadiene
    34 24.5097 1.5373 9-Tetradecenal, (Z)-
    35 30.3053 0.5913 15-Hydroxypentadecanoic acid
    36 31.6831 0.7238 E-9-Tetradecenal
    37 32.9886 10.3582 13-octadecadienol
    38 33.1566 2.9289 cis-Vaccenic acid
    39 33.3425 4.5968 trans-13-Octadecenoic acid
    40 35.8604 0.8797 13-octadecadienol
    41 35.971 1.2193 Eicosane
    42 38.4646 10.2357 cis-11-Hexadecenal

    Note: S/N = Serial number, RT = Retention time.

     | Show Table
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    Figure 6.  Chromatogram of essential oil of E. camaldulensis leaves.

    The results of the in vitro experiment showed a high possibility that the leaf extracts of E. camaldulensis inhibited the α-glucosidase enzyme. This motivated us to evaluate the potential inhibitory role of the phytochemicals of E. camaldulensis and to identify the binding affinity value for each compound. It is crucial to validate the docking protocol to ensure the precision of the docking process. Therefore, the co-crystallized ligand, namely alpha-D-glucopyranose, was eliminated from the α-glucosidase PDB structure. Subsequently, a new alpha-D-glucopyranose was generated by the CORINA server as descried in the methods and used to redock the PDB structure. The CABS Flex 2.0 server effectively re-docked the newly generated ligand into the active site of α-glucosidase (Figure 7), resulting in interactions similar to those observed in the original structure. Despite using blind docking and not specifying the active site, a good match between the docking structure and the original PDB structure was obtained, indicating the docking accuracy.

    Figure 7.  The validation of the docking protocol. α-glucosidase enzyme (pink), along with the redocked generated ligand (blue) and the native ligand, alpha-D-glucopyranose (orange), are presented.

    The phytochemicals isolated from the E. camaldulensis leaves (Table 2) were subjected to docking studies to estimate their antidiabetic effects against α-glucosidase, as illustrated in Table 3 and Figure 8. Additionally, the inhibition constant (Ki) was calculated based on the binding energy (ΔG) using the formula mentioned in the methods section. The results of the docking analysis revealed that the 5.alpha.-Androstan-16-one compound exhibited significant binding affinities towards α-glucosidase compared to other phytochemicals. The two compounds mentioned above produced higher binding affinities compared to the controls, with scores of −8.6 and −8.5 Kcal/mol, respectively, as presented in Table 3. Quercetin exhibited the highest binding affinity among the five controls, with a score of −8.6 Kcal/mol. This score is comparable to the scores obtained by 5.alpha.-Androstan-16-one. A further analysis was conducted on 5.alpha.-Androstan-16-one due to its strong interaction with α-glucosidase. The analysis showed that the compound could interact with the enzyme via 11 amino acids (TYR158, GLN279, PHE303, ASP307, PRO312, LEU313, PHE314, ARG315, ASP352, GLN353, GLU411, and ARG442), as shown in Figure 8.

    Table 3.  The docking scores and Inhibition constant (Ki) of examined compounds against α-glucosidase.
    Compound PubChem CID Docking Score Inhibition constant Ki (µM)
    alpha-D-glucopyranose (Native Inhibitor) 79025 −6.2 27.5
    Quercetin 5280343 −8.6 0.5
    Acarbose 41774 −8.3 0.8
    Miglitol 441314 −5.8 55.4
    Voglibose 444020 −6.4 20.3
    Phytochemicals of Eucalyptus camaldulensis that gave best scores
    5.alpha.-Androstan-16-one 13963520 −8.6 0.5

     | Show Table
    DownLoad: CSV
    Figure 8.  The amino acids located in the active site of α-glucosidase interact with 5.alpha.-Androstan-16-one compound.

    A MD simulation of 10 ns was conducted utilizing the CABS-flex 2.0 server in order to determine the RMSF values for the α-glucosidase-5.alpha.-Androstan-16-one complex, as shown in Figure 9. The fluctuation of atoms throughout the simulations provides insight into the flexibility and stability of various protein residues. A higher RMSF value for the residues suggests an increased flexibility of the amino acid, while lower fluctuations suggest restricted movements during the MD simulation. The fluctuation in the complex was found in the acceptable range between 1 and 3 Å, indicating that there is no binding effect of 5α-androstan-16-one on the α-glucosidase enzyme. The LYS127, ALA145, and SER574 residues exhibited fluctuations higher than 3 Å; however, these exceptions were found outside the active site and did not impact the binding to the ligands. In multiple regions within the active site, 5α-androstan-16-one enhanced the rigidity of the enzyme and improved the stability of binding, as shown in the dashed line box.

    Figure 9.  The RMSF plot (Å) of α-glucosidase enzyme (orange) and 5.alpha.-Androstan-16-one complex (blue). The amino RMSF plots are constructed from the backbone Cα atoms.

    The promising phytochemical, namely 5.alpha.-Androstan-16-one, underwent evaluation to determine its potential as a drug that can be taken orally by humans, in accordance with Lipinski's rule of five (RO5), and was assessed for the ADMET parameters. The compound successfully met Lipinski's rule of five, with only one violation observed due to MLOGP > 4.15. The compound showed a high gastrointestinal absorption. In regard to its solubility, 5.alpha.-Androstan-16-one exhibited a moderate solubility. The compound received enzyme inhibitor scores of 0.34, with neither showing any hepatotoxicity.

    The yield varied greatly according to the extraction solvents (Table 1). The solvent's ability to extract more compounds from the samples may account for the high yield found in the aqueous extracts. The findings are consistent with Poojary et al. [30], who observed a significant yield of extract from the root and bark using an aqueous extraction method, with a reported yield of 10.43%. The extraction process, solvent type, chemical type, and metabolite polarity were the main factors that influenced the yield extract variance between the medicinal plant parts [18]. Choosing the appropriate extraction solvent is significant to obtain a higher yield of compounds. A diverse number of solvents, such as aqueous diethyl ether, ethanol, hexane, methanol, and chloroform, has previously been used to extract bioactive substances in plant parts [31]. Each bioactive compound has a different solubility in specific solvents. Therefore, the correct choice of organic solvent is significant to recover different forms of compounds. It is necessary to select solvents that are safe for use in the industrial production processes.

    In terms of the radical scavenging activity, the high activity of the EO might because the plant is known to be highly aromatic. The Fe3+ complex in tripyridyl-triazine (TPTZ) is reduced to the Fe2+ complex, Fe2+ (TPTZ), which results in a blue colour shift in this process [32]. When compared to their scavenging activity, the antioxidant content of the ethanol, aqueous, and EO extracts did not significantly differ based on their reduction potential. The action of each extract established in the various solvents is explained by the presence of a specific component, such as a hydroxyl group, a methoxyl group, phenolic compounds, flavonoids compounds, or other structures that may be present [18]. The number and type of phytochemical compounds found in the plant extract are solely responsible of the environmental condition [33]. Possible explanations for the observed discrepancy between the DPPH and FRAP assays include differences in the actions or responses of the compounds toward the assay. Multiple studies have conclusively established the importance of oxidative stress in the development and progression of DM [34].

    Therefore, antioxidant compounds such as plant polyphenols have been proposed as potential tools in the fight against and the treatment of this disease. The findings of the DPPH and FRAP assays for antioxidant activity led us to infer that the EO extracted from the leaves had the maximum antioxidant activity. More work is needed to isolate the compounds in the leaves' EOs responsible for its antioxidant properties before it can be used therapeutically. The beneficial effects on glucose homoeostasis can be shown in DM patients when these enzymes are inhibited, as less oligosaccharide and disaccharide hydrolysis occurs [35]. Therefore, blocking the α-glucosidase enzyme is a crucial part of diabetes management [36].

    All the extracts that showed varying levels of activity against the bacterial strains were tested. An increase in activity was observed with increasing concentrations of both the ethanol and aqueous extract and EO (Table 1). The EO demonstrated a superior action compared to the ethanol and aqueous extracts, as well as the ampicillin standard (Table 1). The results were consistent with the findings of Sabo et al. [13], where the EO derived from E. camaldulensis exhibited an antimicrobial activity against a wide range of Gram-positive bacteria (0.07–1.1%) and Gram-negative bacteria (0.01–3.2%). Consequently, the treatment of bacterial infections necessitated the administration of larger quantities of the oil [16].

    E. camaldulensis leaves have long been recommended by traditional herbalists as a potent diabetic treatment, and recent scientific studies have confirmed these assertions. One of the reasons for the high activity of the leaves extracts might be because the secondary metabolites are first produced in the leaves before being transferred to the rest of the plant . The plant's secondary metabolites have crucial roles in disease resistance, pollination, and adaptability. Many aspects of a man's daily life make use of the secondary metabolites produced by the plant's parts. It's common knowledge that these chemical by-products, treated or not, have several biological applications [37].

    Forty-two non-polar compounds identified for the EO of the leaves might be responsible for the high antioxidant and alpha glycosidase inhibition activities. Increasing insulin secretion and pancreatic -cell regeneration are two ways in which the following substances have been found to have anti-diabetic effects [38]. Antioxidant and anti-diabetic effects have been observed in secondary metabolites and bioactive phyto-constituents discovered by GC/MS in a wide range of plants [35]. The chemical composition revealed the presence of 41 compounds with a diverse array of pharmacological activities. Compounds such as Aromadendrin have been recorded to possess numerous pharmacological properties, such as anti-inflammatory, antioxidant, and anti-diabetic attributes [39]. Famous for its anti-inflammatory qualities in treating peptic ulcers, azulene also has anti-tumor and anti-retroviral activities against HIV-1, antimicrobial qualities, including antimicrobial photodynamic therapy, and antifungal qualities. Additionally, it has antineoplastic effects in fighting leukemia [40]. Studies revealed that 9-hexadecenoic acid and trans-13-octadecenoic acid had possible anti-inflammatory properties, suggesting a viable substitute for treating a variety of ailments linked to pain and inflammation [41],[42].

    The results of the MD analysis revealed that the majority of phytochemicals found in E. camaldulensis exhibited a binding score higher than −6.2 Kcal/mol, where the score was obtained by the native inhibitor, as shown in Supplementary Table S1. Typically, in drug design, the primary criteria for selecting potential candidates involves binding free energy values that are usually lower than −6.0 kcal/mol [43].

    The strong inhibition observed by the in silico study aligns with the in vitro findings, where the E. camaldulensis extracts demonstrated inhibition of α-glucosidase activity at a percent inhibition ranging from 60-78 %, which is comparable to the percent inhibition of Quercetin at 84 %. The selection of Quercetin as a positive control in the docking study was based on its use in the in vitro study. Upon comparing the level of inhibition exhibited by Quercetin against α-glucosidase in both studies, it was observed that it achieved a significant degree of inhibition nearly equivalent to the inhibition observed for most of the phytochemicals, particularly the 5.alpha.-Androstan-16-one compound. Our in silico results showed that the compound 5.alpha.-Androstan-16-one displayed a significant inhibitory activity, with a binding affinity of −8.6 Kcal/mol. Interestingly, these scores are consistent with the binding affinity of Quercetin, which recorded −8.6 kcal/mol. Three residues—TYR158, PHE303, and ARG315—formed non-bond pi-alkyl interactions with 5.alpha.-Androstan-16-one. The pi-alkyl interaction was found to improve the hydrophobic interaction of the ligand in the binding pocket of the receptor, ultimately enhancing its affinity [44]. The strong binding affinity seen in the α-glucosidase-5.alpha.-Androstan-16-one complex may be explained by the presence of pi-alkyl interactions. The inhibition constant (Ki) of 5.alpha.-Androstan-16-one showed the lowest value of 0.5 µM, which is similar to that obtained by 0.5 µM Quercetin. It is known that the lower the Ki value, the greater the drug's efficacy [45]. No previous studies were found in the literature that examined the inhibitory activity of 5.alpha.-Androstan-16-one against α-glucosidase.

    The MD simulation carried out on the α-glucosidase-5.alpha.-Androstan-16-one complex revealed that the RMSF fluctuation fell within the acceptable range of 1 to 3 Å. This range is considered as the acceptable RMSF criterion to determine protein stability [46]. The results from the MD analysis further demonstrated that the interaction with 5.alpha.-Androstan-16-one led to the enhanced rigidity and stability of α-glucosidase, as evidenced by the reduced RMSF values in various areas of the active site. The correlation between the lower RMSF values and enhanced protein stability was documented by [47]. The terminals of the complex exhibited some high fluctuations, which is a phenomenon that is frequently observed in proteins [48]. The protein termini are often found on the surface of proteins rather than buried in the core, which contributes to the flexibility of the protein terminals [49].

    Drugs such as acarbose, miglitol, and voglibose, which were approved by the FDA, frequently cause stomach-related side effects that hinder their use. As a result, the quest for novel, more potent medications with reduced adverse reactions and lower expenses continues to be a focus of research [50]. In a recent study, 5α-androstan-16-one showed a stronger competitive inhibition against α-glucosidase compared to FDA-approved diabetes drugs. This natural compound can be a promising diabetic medication with no or fewer side effects compared to those that are usually present in synthetic drugs. In general, the present study revealed that E. camaldulensis leaves exhibited a wide range of metabolites that significantly played a role in their antioxidant, anti-diabetic, and antimicrobial potential through unknown mechanisms. The study laid a foundation for pharmacological studies on E. camaldulensis. The study suggests that the leaves could be used to make herbal treatments for diabetic people and infectious diseases.

    The findings demonstrated that E. camaldulensis has a high antioxidant capacity caused by free radicals and FRAP. Furthermore, E. camaldulensis leaves inhibited α-glucosidase at 78 ± 2.1 %. Based on a GCMS analysis, the following chemicals were found to be dominant: cis-11-hexadecenal (10.2%), trans-13-octadecenoic acid (9.5%), and 6-Octadecenoic acid, methyl ester, (Z)- (8.8%). The compound 5.alpha.-Androstan-16-one exhibited a greater competitive inhibition of α-glucosidase compared to FDA-approved antidiabetic medications such as Acarbose, Miglitol, and Voglibose. 5.alpha.-Androstan-16-one has the potential to serve as an effective treatment for diabetes, offering minimal or no side effects that are commonly associated with synthetic medications. The study suggests that the leaves could be used to make herbal treatments for diabetic people. In order to corroborate our in silico findings, further in vitro and in vivo studies are necessary.

    The authors declare that they have not used Artificial Intelligence (AI) tools in the creation of this article.

    [1] Woodcock CL, Ghosh RP (2010) Chromatin higher-order structure and dynamics. Cold Spring Harb Perspect Biol 2: a000596.
    [2] Sexton T, Cavalli G (2015) The role of chromosome domains in shaping the functional genome. Cell 160: 1049–1059. doi: 10.1016/j.cell.2015.02.040
    [3] Miné-Hattab J, Rothstein R (2012) Increased chromosome mobility facilitates homology search during recombination. Nat Cell Biol 14: 510–517. doi: 10.1038/ncb2472
    [4] Khurana S, Kruhlak MJ, Kim J, et al. (2014) A macrohistone variant links dynamic chromatin compaction to BRCA1-dependent genome maintenance. Cell Rep 8: 1049–1062. doi: 10.1016/j.celrep.2014.07.024
    [5] Robinson PJJ, Fairall L, Huynh VAT, et al. (2006) EM measurements define the dimensions of the “30-nm” chromatin fiber: evidence for a compact, interdigitated structure. Proc Natl Acad Sci U S A 103: 6506–6511. doi: 10.1073/pnas.0601212103
    [6] Schalch T, Duda S, Sargent DF, et al. (2005) X-ray structure of a tetranucleosome and its implications for the chromatin fibre. Nature 436: 138–141. doi: 10.1038/nature03686
    [7] Joti Y, Hikima T, Nishino, et al. (2012) Chromosomes without a 30-nm chromatin fiber. Nucl Austin Tex 3: 404–410.
    [8] Fussner E, Ahmed K, Dehghani, et al. (2010) Changes in chromatin fiber density as a marker for pluripotency. Cold Spring Harb Symp Quant. Biol 75: 245–249. doi: 10.1101/sqb.2010.75.012
    [9] Yokota H, van den Engh G, Hearst JE, et al. (1995) Evidence for the organization of chromatin in megabase pair-sized loops arranged along a random walk path in the human G0/G1 interphase nucleus. J Cell Biol 130: 1239–1249. doi: 10.1083/jcb.130.6.1239
    [10] Petrascheck M, Escher D, Mahmoudi T et al. (2005) DNA looping induced by a transcriptional enhancer in vivo. Nucleic Acids Res. 33: 3743–3750. doi: 10.1093/nar/gki689
    [11] Pombo A, Dillon N (2015) Three-dimensional genome architecture: players and mechanisms. Nat Rev Mol Cell Biol 16: 245–257.
    [12] Dixon JR, Selvaraj S, Yue F, et al. (2012) Topological domains in mammalian genomes identified by analysis of chromatin interactions. Nature 485: 376–380. doi: 10.1038/nature11082
    [13] Nora EP, Lajoie BR, Schulz EG, et al. (2012) Spatial partitioning of the regulatory landscape of the X-inactivation centre. Nature 485: 381–385. doi: 10.1038/nature11049
    [14] Sexton T, Yaffe E, Kenigsberg E, et al. (2012) Three-dimensional folding and functional organization principles of the Drosophila genome. Cell 148: 458–472. doi: 10.1016/j.cell.2012.01.010
    [15] Lieberman-Aiden E, van Berkum NL, Williams L, et al. (2009) Comprehensive mapping of long-range interactions reveals folding principles of the human genome. Science 326: 289–293. doi: 10.1126/science.1181369
    [16] Bolzer A, Kreth G, Solovei I, et al. (2005) Three-dimensional maps of all chromosomes in human male fibroblast nuclei and prometaphase rosettes. PLoS Biol 3: e157. doi: 10.1371/journal.pbio.0030157
    [17] Cremer T, Cremer M (2010) Chromosome territories. Cold Spring Harb Perspect Biol 2: a003889.
    [18] Kinney NA, Onufriev AV, Sharakhov IV (2015) Quantified effects of chromosome-nuclear envelope attachments on 3D organization of chromosomes. Nucl Austin Tex 6: 212–224.
    [19] Heun P, Laroche T, Shimada K, et al. (2001) Chromosome dynamics in the yeast interphase nucleus. Science 294: 2181–2186. doi: 10.1126/science.1065366
    [20] Levi V, Ruan Q, Plutz M, et al. (2005) Chromatin dynamics in interphase cells revealed by tracking in a two-photon excitation microscope. Biophys J 89: 4275–4285. doi: 10.1529/biophysj.105.066670
    [21] Hubner M, Spector D (2010) Chromatin Dynamics. Annu Rev Biophys 39: 471–489.
    [22] Javer A, Long Z, Nugent E, et al. (2013) Short-time movement of E. coli chromosomal loci depends on coordinate and subcellular localization. Nat Commun. 4: 3003.
    [23] Gibcus JH, Dekker J (2013) The hierarchy of the 3D genome. Mol Cell 49: 773–782. doi: 10.1016/j.molcel.2013.02.011
    [24] Weber SC, Spakowitz AJ, Theriot JA (2012) Nonthermal ATP-dependent fluctuations contribute to the in vivo motion of chromosomal loci. Proc Natl Acad Sci U S A 109: 7338–7343. doi: 10.1073/pnas.1119505109
    [25] Pliss A, Malyavantham KS, Bhattacharya S, et al. (2013) Chromatin dynamics in living cells: identification of oscillatory motion. J Cell Physiol 228, 609–616.
    [26] Gerlich D, Beaudouin J, Kalbfuss B, et al. (2003) Global chromosome positions are transmitted through mitosis in mammalian cells. Cell 112: 751–764. doi: 10.1016/S0092-8674(03)00189-2
    [27] Walter J, Schermelleh L, Cremer M, et al. (2003) Chromosome order in HeLa cells changes during mitosis and early G1, but is stably maintained during subsequent interphase stages. J Cell Biol 160: 685–697. doi: 10.1083/jcb.200211103
    [28] Müller I, Boyle S, Singer RH, et al. (2010) Stable morphology, but dynamic internal reorganisation, of interphase human chromosomes in living cells. PloS One 5: e11560. doi: 10.1371/journal.pone.0011560
    [29] Kruhlak MJ, Celeste A, Dellaire G, et al. (2006) Changes in chromatin structure and mobility in living cells at sites of DNA double-strand breaks. J Cell Biol 172: 823–834. doi: 10.1083/jcb.200510015
    [30] Zink D, Cremer T, Saffrich R, et al. (1998) Structure and dynamics of human interphase chromosome territories in vivo. Hum Genet 102: 241–251. doi: 10.1007/s004390050686
    [31] Jackson DA, Pombo A (1998) Replicon clusters are stable units of chromosome structure: evidence that nuclear organization contributes to the efficient activation and propagation of S phase in human cells. J Cell Biol 140: 1285–1295. doi: 10.1083/jcb.140.6.1285
    [32] Robinett CC, Straight A, Li G, et al. (1996) In vivo localization of DNA sequences and visualization of large-scale chromatin organization using lac operator/repressor recognition. J Cell Biol 135: 1685–1700. doi: 10.1083/jcb.135.6.1685
    [33] Jacome A, Fernandez-Capetillo O (2011) Lac operator repeats generate a traceable fragile site in mammalian cells. EMBO Rep 12: 1032–1038. doi: 10.1038/embor.2011.158
    [34] Dubarry M, Loïodice I, Chen CL, et al. (2011) Tight protein-DNA interactions favor gene silencing. Genes Dev 25: 1365–1370. doi: 10.1101/gad.611011
    [35] Saad H, Gallardo F, Dalvai M, et al. (2014) DNA dynamics during early double-strand break processing revealed by non-intrusive imaging of living cells. PLoS Genet 10: e1004187. doi: 10.1371/journal.pgen.1004187
    [36] Chen B, Gilbert LA, Cimini BA, et al. (2013) Dynamic imaging of genomic loci in living human cells by an optimized CRISPR/Cas system. Cell 155: 1479–1491. doi: 10.1016/j.cell.2013.12.001
    [37] Miyanari Y, Ziegler-Birling C, Torres-Padilla M-E (2013) Live visualization of chromatin dynamics with fluorescent TALEs. Nat Struct Mol Biol 20: 1321–1324. doi: 10.1038/nsmb.2680
    [38] Zidovska A, Weitz DA, Mitchison TJ (2013) Micron-scale coherence in interphase chromatin dynamics. Proc Natl Acad Sci U S A 110: 15555–15560. doi: 10.1073/pnas.1220313110
    [39] Hinde E, Kong X, Yokomori K, et al. (2014) Chromatin dynamics during DNA repair revealed by pair correlation analysis of molecular flow in the nucleus. Biophys J 107: 55–65. doi: 10.1016/j.bpj.2014.05.027
    [40] Marshall WF, Straight A, Marko JF, et al. (1997) Interphase chromosomes undergo constrained diffusional motion in living cells. Curr Biol CB 7: 930–939. doi: 10.1016/S0960-9822(06)00412-X
    [41] Bornfleth H, Edelmann P, Zink D, et al. (1999) Quantitative motion analysis of subchromosomal foci in living cells using four-dimensional microscopy. Biophys J 77: 2871–2886. doi: 10.1016/S0006-3495(99)77119-5
    [42] Qian H, Sheetz MP, Elson EL (1991) Single particle tracking. Analysis of diffusion and flow in two-dimensional systems. Biophys J 60: 910–921.
    [43] Rosa A, Everaers R (2008) Structure and dynamics of interphase chromosomes. PLoS Comput Biol 4: e1000153. doi: 10.1371/journal.pcbi.1000153
    [44] Hajjoul H, Mathon J, Ranchon H, et al. (2013) High-throughput chromatin motion tracking in living yeast reveals the flexibility of the fiber throughout the genome. Genome Res 23: 1829–1838.
    [45] Havlin S, Ben-Avraham D (2002) Diffusion in disordered media. Adv Phys 51: 187–292. doi: 10.1080/00018730110116353
    [46] Doi M (1996) Introduction to polymer physics Oxford University Press.
    [47] Bronstein I, Israel Y, Kepten E, et al. (2009) Transient anomalous diffusion of telomeres in the nucleus of mammalian cells. Phys Rev Lett 103: 018102. doi: 10.1103/PhysRevLett.103.018102
    [48] Dion V, Kalck V, Seeber A, et al. (2013) Cohesin and the nucleolus constrain the mobility of spontaneous repair foci. EMBO Rep 14: 984–991. doi: 10.1038/embor.2013.142
    [49] Gartenberg MR, Neumann FR, Laroche T, et al. (2004) Sir-mediated repression can occur independently of chromosomal and subnuclear contexts. Cell 119: 955–967. doi: 10.1016/j.cell.2004.11.008
    [50] Hu Y, Kireev I, Plutz M, et al. (2009) Large-scale chromatin structure of inducible genes: transcription on a condensed, linear template. J Cell Biol 185: 87–100. doi: 10.1083/jcb.200809196
    [51] Neumann FR, Dion V, Gehlen LR, et al. (2012) Targeted INO80 enhances subnuclear chromatin movement and ectopic homologous recombination. Genes Dev 26: 369–383. doi: 10.1101/gad.176156.111
    [52] Chuang C-H, Carpenter AE, Fuchsova B, et al. (2006) Long-range directional movement of an interphase chromosome site. Curr Biol 16: 825–831.
    [53] Khanna N, Hu Y, Belmont AS (2014) HSP70 transgene directed motion to nuclear speckles facilitates heat shock activation. Curr Biol 24: 1138–1144.
    [54] Chubb JR, Boyle S, Perry P, et al. (2002) Chromatin motion is constrained by association with nuclear compartments in human cells. Curr Biol 12: 439–445.
    [55] Lucas JS, Zhang Y, Dudko OK, et al. (2014) 3D trajectories adopted by coding and regulatory DNA elements: first-passage times for genomic interactions. Cell 158: 339–352. doi: 10.1016/j.cell.2014.05.036
    [56] Daley JM, Gaines WA, Kwon Y, et al. (2014) Regulation of DNA pairing in homologous recombination. Cold Spring Harb Perspect Biol 6: a017954. doi: 10.1101/cshperspect.a017954
    [57] Lieber MR (2010) The mechanism of double-strand DNA break repair by the nonhomologous DNA end-joining pathway. Annu Rev Biochem 79: 181–211. doi: 10.1146/annurev.biochem.052308.093131
    [58] Sonoda E, Hochegger H, Saberi A, et al. (2006) Differential usage of non-homologous end-joining and homologous recombination in double strand break repair. DNA Repair 5: 1021–1029. doi: 10.1016/j.dnarep.2006.05.022
    [59] Dion V, Kalck V, Horigome C, et al. (2012) Increased mobility of double-strand breaks requires Mec1, Rad9 and the homologous recombination machinery. Nat Cell Biol 14: 502–509. doi: 10.1038/ncb2465
    [60] Seeber A, Dion V, Gasser SM (2013) Checkpoint kinases and the INO80 nucleosome remodeling complex enhance global chromatin mobility in response to DNA damage. Genes Dev 27: 1999–2008. doi: 10.1101/gad.222992.113
    [61] Lisby M, Mortensen UH, Rothstein R (2003) Colocalization of multiple DNA double-strand breaks at a single Rad52 repair centre. Nat Cell Biol 5: 572–577. doi: 10.1038/ncb997
    [62] Nagai S, Dubrana K, Tsai-Pflugfelder M, et al. (2008) Functional targeting of DNA damage to a nuclear pore-associated SUMO-dependent ubiquitin ligase. Science 322: 597–602. doi: 10.1126/science.1162790
    [63] Kalocsay M, Hiller NJ, Jentsch S (2009) Chromosome-wide Rad51 spreading and SUMO-H2A.Z-dependent chromosome fixation in response to a persistent DNA double-strand break. Mol Cell 33: 335–343.
    [64] Krawczyk PM, Borovski T, Stap J, et al. (2012) Chromatin mobility is increased at sites of DNA double-strand breaks. J Cell Sci 125: 2127–2133. doi: 10.1242/jcs.089847
    [65] Aten JA, Stap J, Krawczyk PM, et al. (2004) Dynamics of DNA double-strand breaks revealed by clustering of damaged chromosome domains. Science 303: 92–95. doi: 10.1126/science.1088845
    [66] Dimitrova N, Chen Y-CM, Spector DL, et al. (2008) 53BP1 promotes non-homologous end joining of telomeres by increasing chromatin mobility. Nature 456: 524–528. doi: 10.1038/nature07433
    [67] Jakob B, Splinter J, Conrad S, et al. (2011) DNA double-strand breaks in heterochromatin elicit fast repair protein recruitment, histone H2AX phosphorylation and relocation to euchromatin. Nucleic Acids Res 39: 6489–6499. doi: 10.1093/nar/gkr230
    [68] Ježková L, Falk M, Falková I, et al. (2014) Function of chromatin structure and dynamics in DNA damage, repair and misrepair: γ-rays and protons in action. Appl Radiat Isot Data Instrum Methods Use Agric Ind Med 83: 128–136.
    [69] Chiolo I, Minoda A, Colmenares SU, et al. (2011) Double-strand breaks in heterochromatin move outside of a dynamic HP1a domain to complete recombinational repair. Cell 144: 732–744. doi: 10.1016/j.cell.2011.02.012
    [70] Nelms BE, Maser RS, MacKay JF, et al. (1998) In situ visualization of DNA double-strand break repair in human fibroblasts. Science 280: 590–592. doi: 10.1126/science.280.5363.590
    [71] Jakob B, Splinter J, Durante M, et al. (2009) Live cell microscopy analysis of radiation-induced DNA double-strand break motion. Proc Natl Acad Sci U S A 106: 3172–3177. doi: 10.1073/pnas.0810987106
    [72] Soutoglou E, Dorn JF, Sengupta K, et al. (2007) Positional stability of single double-strand breaks in mammalian cells. Nat Cell Biol 9: 675–682. doi: 10.1038/ncb1591
    [73] Roukos V, Voss TC, Schmidt CK, et al. (2013) Spatial dynamics of chromosome translocations in living cells. Science 341: 660–664. doi: 10.1126/science.1237150
    [74] Smerdon MJ, Lieberman MW (1978) Nucleosome rearrangement in human chromatin during UV-induced DNA- reapir synthesis. Proc Natl Acad Sci U S A 75: 4238–4241. doi: 10.1073/pnas.75.9.4238
    [75] Ziv Y, Bielopolski D, Galanty Y, et al. (2006) Chromatin relaxation in response to DNA double-strand breaks is modulated by a novel ATM- and KAP-1 dependent pathway. Nat Cell Biol 8: 870–876. doi: 10.1038/ncb1446
    [76] Burgess RC, Burman B, Kruhlak MJ, et al. (2014) Activation of DNA damage response signaling by condensed chromatin. Cell Rep 9: 1703–1717. doi: 10.1016/j.celrep.2014.10.060
    [77] Smeenk G, Wiegant WW, Marteijn JA, et al. (2013) Poly(ADP-ribosyl)ation links the chromatin remodeler SMARCA5/SNF2H to RNF168-dependent DNA damage signaling. J Cell Sci 126: 889–903. doi: 10.1242/jcs.109413
    [78] Baldeyron C, Soria G, Roche D, et al. (2011) HP1alpha recruitment to DNA damage by p150CAF-1 promotes homologous recombination repair. J Cell Biol 193: 81–95. doi: 10.1083/jcb.201101030
    [79] Ayrapetov MK, Gursoy-Yuzugullu O, Xu C, et al. (2014) DNA double-strand breaks promote methylation of histone H3 on lysine 9 and transient formation of repressive chromatin. Proc Natl Acad Sci U S A 111: 9169–9174. doi: 10.1073/pnas.1403565111
    [80] Zhu L, Brangwynne CP (2015) Nuclear bodies: the emerging biophysics of nucleoplasmic phases. Curr Opin Cell Biol 34: 23–30. doi: 10.1016/j.ceb.2015.04.003
    [81] Chubb JR, Bickmore WA (2003) Considering nuclear compartmentalization in the light of nuclear dynamics. Cell 112: 403–406. doi: 10.1016/S0092-8674(03)00078-3
    [82] Lemaître C, Soutoglou E (2015) DSB (Im)mobility and DNA repair compartmentalization in mammalian cells. J Mol Biol 427: 652–658. doi: 10.1016/j.jmb.2014.11.014
    [83] Klein IA, Resch W, Jankovic M, et al. (2011) Translocation-capture sequencing reveals the extent and nature of chromosomal rearrangements in B lymphocytes. Cell 147: 95–106. doi: 10.1016/j.cell.2011.07.048
    [84] Murr R, Loizou JI, Yang Y-G, et al. (2006) Histone acetylation by Trrap-Tip60 modulates loading of repair proteins and repair of DNA double-strand breaks. Nat Cell Biol 8: 91–99. doi: 10.1038/ncb1343
    [85] Verschure PJ, van der Kraan I, Manders EMM, et al. (2003) Condensed chromatin domains in the mammalian nucleus are accessible to large macromolecules. EMBO Rep 4: 861–866. doi: 10.1038/sj.embor.embor922
    [86] Bancaud A, Huet S, Daigle N, et al. (2009) Molecular crowding affects diffusion and binding of nuclear proteins in heterochromatin and reveals the fractal organization of chromatin. EMBO J 28: 3785–3798. doi: 10.1038/emboj.2009.340
    [87] Dinant C, de Jager M, Essers J, et al. (2007) Activation of multiple DNA repair pathways by sub-nuclear damage induction methods. J Cell Sci 120: 2731–2740. doi: 10.1242/jcs.004523
    [88] Kong X, Mohanty SK, Stephens J, et al. (2009) Comparative analysis of different laser systems to study cellular responses to DNA damage in mammalian cells. Nucleic Acids Res 37: e68. doi: 10.1093/nar/gkp221
    [89] Gilbert N, Allan J (2014) Supercoiling in DNA and chromatin. Curr Opin Genet Dev 25: 15–21. doi: 10.1016/j.gde.2013.10.013
    [90] Elbel T, Langowski J (2015) The effect of DNA supercoiling on nucleosome structure and stability. J Phys Condens Matter Inst Phys J 27: 064105. doi: 10.1088/0953-8984/27/6/064105
    [91] Polo SE (2015) Reshaping chromatin after DNA damage: the choreography of histone proteins. J Mol Biol 427: 626–636. doi: 10.1016/j.jmb.2014.05.025
    [92] Downs JA, Lowndes NF, Jackson SP (2000) A role for Saccharomyces cerevisiae histone H2A in DNA repair. Nature 408: 1001–1004. doi: 10.1038/35050000
    [93] Heo K, Kim H, Choi SH, et al. (2008) FACT-mediated exchange of histone variant H2AX regulated by phosphorylation of H2AX and ADP-ribosylation of Spt16. Mol Cell 30: 86–97. doi: 10.1016/j.molcel.2008.02.029
    [94] Li A, Yu Y, Lee S-C, et al. (2010) Phosphorylation of histone H2A.X by DNA-dependent protein kinase is not affected by core histone acetylation, but it alters nucleosome stability and histone H1 binding. J Biol Chem 285: 17778–17788.
    [95] Golia B, Singh HR, Timinszky G (2015) Poly-ADP-ribosylation signaling during DNA damage repair. Front Biosci Landmark Ed 20: 440–457. doi: 10.2741/4318
    [96] Poirier GG, de Murcia G, Jongstra-Bilen J, et al. (1982) Poly(ADP-ribosyl)ation of polynucleosomes causes relaxation of chromatin structure. Proc Natl Acad Sci U S A 79: 3423–3427. doi: 10.1073/pnas.79.11.3423
    [97] de Murcia G, Huletsky A, Lamarre D, et al. (1986) Modulation of chromatin superstructure induced by poly(ADP-ribose) synthesis and degradation. J Biol Chem 261: 7011–7017.
    [98] Xu Y, Ayrapetov MK, Xu C, et al. (2012) Histone H2A.Z controls a critical chromatin remodeling step required for DNA double-strand break repair. Mol Cell 48: 723–733.
    [99] Clapier CR, Cairns BR (2009) The biology of chromatin remodeling complexes. Annu Rev Biochem 78: 273–304. doi: 10.1146/annurev.biochem.77.062706.153223
    [100] Cheezum MK, Walker WF, Guilford WH (2001) Quantitative comparison of algorithms for tracking single fluorescent particles. Biophys J 81: 2378–2388. doi: 10.1016/S0006-3495(01)75884-5
    [101] Wombacher R, Heidbreder M, van de Linde S, et al. (2010) Live-cell super-resolution imaging with trimethoprim conjugates. Nat Methods 7: 717–719. doi: 10.1038/nmeth.1489
    [102] Benke A, Manley S (2012) Live-cell dSTORM of cellular DNA based on direct DNA labeling. Chembiochem Eur J Chem Biol 13: 298–301. doi: 10.1002/cbic.201100679
    [103] Hihara S, Pack C-G, Kaizu K, et al. (2012) Local nucleosome dynamics facilitate chromatin accessibility in living mammalian cells. Cell Rep 2: 1645–1656. doi: 10.1016/j.celrep.2012.11.008
    [104] Récamier V, Izeddin I, Bosanac L, et al. (2014) Single cell correlation fractal dimension of chromatin: a framework to interpret 3D single molecule super-resolution. Nucl Austin Tex 5: 75–84.
    [105] Ricci MA, Manzo C, García-Parajo MF, et al. (2015) Chromatin fibers are formed by heterogeneous groups of nucleosomes in vivo. Cell 160: 1145–1158. doi: 10.1016/j.cell.2015.01.054
    [106] Zhang Y, Máté G, Müller P, et al. (2015) Radiation induced chromatin conformation changes analysed by fluorescent localization microscopy, statistical physics, and graph theory. PloS One 10: e0128555. doi: 10.1371/journal.pone.0128555
    [107] Llères D, James J, Swift S, et al. (2009) Quantitative analysis of chromatin compaction in living cells using FLIM-FRET. J Cell Biol 187: 481–496. doi: 10.1083/jcb.200907029
    [108] Emanuel M, Radja NH, Henriksson A, et al. (2009) The physics behind the larger scale organization of DNA in eukaryotes. Phys Biol 6: 025008. doi: 10.1088/1478-3975/6/2/025008
    [109] Rouse P (1953) A Theory of the Linear Viscoelastic Properties of Dilute Solutions of Coiling Polymers. J Chem Phys 21: 1272–1280. doi: 10.1063/1.1699180
    [110] Weber SC, Spakowitz AJ, Theriot JA (2010) Bacterial chromosomal loci move subdiffusively through a viscoelastic cytoplasm. Phys Rev Lett 104: 238102. doi: 10.1103/PhysRevLett.104.238102
    [111] Metzler R, Jeon J-H, Cherstvy AG, et al. (2014) Anomalous diffusion models and their properties: non-stationarity, non-ergodicity, and ageing at the centenary of single particle tracking. Phys Chem Chem Phys 16: 24128–24164.
    [112] Mirny LA (2011) The fractal globule as a model of chromatin architecture in the cell. Chromosome Res Int J Mol Supramol Evol Asp Chromosome Biol 19: 37–51.
    [113] Huet S, Lavelle C, Ranchon H, et al. (2014) Relevance and limitations of crowding, fractal, and polymer models to describe nuclear architecture. Int Rev Cell Mol Biol 307: 443–479. doi: 10.1016/B978-0-12-800046-5.00013-8
    [114] Barbieri M, Chotalia M, Fraser J, et al. (2012) Complexity of chromatin folding is captured by the strings and binders switch model. Proc Natl Acad Sci U S A 109: 16173–16178. doi: 10.1073/pnas.1204799109
    [115] Mateos-Langerak J, Bohn M, de Leeuw W, et al. (2009) Spatially confined folding of chromatin in the interphase nucleus. Proc Natl Acad Sci U S A 106: 3812–3817. doi: 10.1073/pnas.0809501106
    [116] Bohn M, Heermann DW (2010) Diffusion-driven looping provides a consistent framework for chromatin organization. PloS One 5: e12218. doi: 10.1371/journal.pone.0012218
    [117] Jerabek H, Heermann DW (2014) How chromatin looping and nuclear envelope attachment affect genome organization in eukaryotic cell nuclei. Int Rev Cell Mol Biol 307: 351–381. doi: 10.1016/B978-0-12-800046-5.00010-2
    [118] Cook PR, Marenduzzo D (2009) Entropic organization of interphase chromosomes. J Cell Biol 186: 825–834.
    [119] Bohn M, Heermann DW (2011) Repulsive forces between looping chromosomes induce entropy-driven segregation. PloS One 6: e14428. doi: 10.1371/journal.pone.0014428
    [120] Jost D, Carrivain P, Cavalli G, et al. (2014) Modeling epigenome folding: formation and dynamics of topologically associated chromatin domains. Nucleic Acids Res 42: 9553–9561. doi: 10.1093/nar/gku698
    [121] Finan K, Cook PR, Marenduzzo D (2011) Non-specific (entropic) forces as major determinants of the structure of mammalian chromosomes. Chromosome Res Int J Mol Supramol Evol Asp Chromosome Biol 19: 53–61. doi: 10.1007/s10577-010-9150-y
    [122] Zhang B, Wolynes PG (2015) Topology, structures, and energy landscapes of human chromosomes. Proc Natl. Acad Sci U S A 112: 6062–6067. doi: 10.1073/pnas.1506257112
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