Plant Metabolic Gene Clusters: Evolution, Organization, and Their Applications in Synthetic Biology.

Plants are a remarkable source of high-value specialized metabolites having significant physiological and ecological functions. Genes responsible for synthesizing specialized metabolites are often clustered together for a coordinated expression, which is commonly observed in bacteria and filamentous fungi. Similar to prokaryotic gene clustering, plants do have gene clusters encoding enzymes involved in the biosynthesis of specialized metabolites. More than 20 gene clusters involved in the biosynthesis of diverse metabolites have been identified across the plant kingdom. Recent studies demonstrate that gene clusters are evolved through gene duplications and neofunctionalization of primary metabolic pathway genes. Often, these clusters are tightly regulated at nucleosome level. The prevalence of gene clusters related to specialized metabolites offers an attractive possibility of an untapped source of highly useful biomolecules. Accordingly, the identification and functional characterization of novel biosynthetic pathways in plants need to be worked out. In this review, we summarize insights into the evolution of gene clusters and discuss the organization and importance of specific gene clusters in the biosynthesis of specialized metabolites. Regulatory mechanisms which operate in some of the important gene clusters have also been briefly described. Finally, we highlight the importance of gene clusters to develop future metabolic engineering or synthetic biology strategies for the heterologous production of novel metabolites.

Identification of Markers for Root Traits Related to Drought Tolerance Using Traditional Rice Germplasm.

Drought is one of the important constraints affecting rice productivity worldwide. The vigorous shoot and deep root system help to improve drought resistance. In present era, genome-wide association study (GWAS) is the preferred method for mapping of QTLs for complex traits such as root and drought tolerance traits. In the present study, 114 rice genotypes were evaluated for various root and shoot traits under water stress conditions. All genotypes showed a significant amount of variation for various root and shoot traits. Correlation analysis revealed that high dry shoot weight and fresh shoot weight is associated with root length, root volume, fresh root weight and dry root weight. A total of 11 significant marker-trait associations were detected for various root, shoot and drought tolerance traits with the coefficient of determination (R2) ranging from 18.99 to 53.41%. Marker RM252 and RM212 showed association with three root traits which suggests their scope for improvement of root system. In the present study, a novel QTL was detected for root length associated with RM127, explaining 19.30% of variation. The marker alleles with increasing phenotypic effects for root and drought-tolerant traits can be exploited for improvement of root and drought tolerance traits using marker-assisted selection.

Functional characterization of a defense-responsive bulnesol/elemol synthase from potato.

Terpene synthases (TPSs) produce a variety of terpenoids that play numerous functional roles in primary and secondary metabolism, as well as in ecological interactions. Here, we report the functional characterization of an inducible potato TPS gene encoding bulnesol/elemol synthase (StBUS/ELS). The expression of StBUS/ELS in potato leaves was significantly induced in response to both bacterial (Pseudomonas syringae) and fungal (Alternaria solani) infection as well as methyl jasmonate treatment, indicating its role in defense. The leaves exhibited the highest StBUS/ELS expression followed by the stem with least and similar expression in tuber, sprout and root. Recombinant StBUS/ELS catalyzed the formation of different sesquiterpenes by utilizing farnesyl diphosphate as substrate, and the monoterpene geraniol from geranyl diphosphate. Among the sesquiterpenes formed by StBUS/ELS, elemol was the predominant product followed by α-bulnesene, bulnesol and ß-elemene. Further gas chromatography-mass spectrometry (GC-MS) analysis of StBUS/ELS assay products at different injection temperatures revealed elemol and bulnesol as the major products at 275 and 200/150°C, respectively, without much change in the levels of minor products. This indicated thermal rearrangement of bulnesol into elemol at higher temperatures. Transient overexpression of StBUS/ELS in potato leaves conferred tolerance against the growth of bacteria P. syringae and Ralstonia solanacearum, and the fungus A. solani. Further, expression analysis of pathogenesis-related (PR) genes in StBUS/ELS overexpressing leaves showed no significant change in comparison to control, indicating a direct involvement of StBUS/ELS enzymatic products against pathogens. Overall, our study suggested that StBUS/ELS is a pathogen-inducible TPS encoding bulnesol/elemol synthase and could provide a direct role in defense against biotic stress in potato.

Identification of clinical and psychosocial characteristics associated with perinatal depression in the south Indian population.

BACKGROUND: Longitudinal perinatal depression (PND) data is sparsely available in the Indian population. We have employed Edinburgh Postnatal Depression Scale (EPDS) to assess the prevalence and identify characteristics associated with PND in the south Indian population. PND was assessed longitudinally using EPDS scores with traditional cut-off approach as well as a novel method of latent class mixture modeling (LCMM). The LCMM method, to the best of our knowledge, has been used for the first time in the Indian population. METHODS: Three hundred and forty seven women, predominantly from economically-weaker sections of rural and urban South India were longitudinally assessed for antenatal depression (AD) and postnatal depression (PD) using EPDS cutoff-scores ≥13 and ≥10, respectively. Uni/multivariable analyses were used to identify PND associated characteristics. LCMM was then implemented, followed by risk characteristics identification. RESULTS: PND prevalence from traditional approach was 24.50 % (12.68 % AD; 18.16% PD). Characteristics associated with PND were urban-site and recent adverse life events. Irregular menstrual history and chronic health issues were associated with AD and PD, respectively. Three distinct PND trajectories were observed from LCMM-analysis: low-risk (76.08%), medium-risk (19.89%) and high-risk (4.04%). Urban-site, recent adverse life events, irregular menstrual history and pregnancy complications were associated with medium-risk/high-risk trajectories. LIMITATIONS: EPDS is a screening tool and not a diagnostic tool for depression. Since the study population included women from economically-weaker sections, the results need verification in other socio-economic groups. CONCLUSIONS: Both the traditional cut-off-based approach and LCMM provided very similar conclusions regarding the prevalence of PND and characteristics associated with it. Higher PND prevalence was observed in urban women compared to rural women. In low-income countries, identifying risk characteristics associated with PND is a critical component in designing prevention strategies for PND related conditions because of the limited access to mental health resources.

Variability Assessment for Root and Drought Tolerance Traits and Genetic Diversity Analysis of Rice Germplasm using SSR Markers.

The studies on genetic variation, diversity and population structure of rice germplasm of North East India could be an important step for improvements of abiotic and biotic stress tolerance in rice. Genetic diversity and genetic relatedness among 114 rice genotypes of North East India were assessed using genotypic data of 65 SSR markers and phenotypic data. The phenotypic diversity analysis showed the considerable variation across genotypes for root, shoot and drought tolerance traits. The principal component analysis (PCA) revealed the fresh shoot weight, root volume, dry shoot weight, fresh root weight and drought score as a major contributor to diversity. Genotyping of 114 rice genotypes using 65 SSR markers detected 147 alleles with the average polymorphic information content (PIC) value of 0.51. Population structure analysis using the Bayesian clustering model approach, distance-based neighbor-joining cluster and principal coordinate analysis using genotypic data grouped the accession into three sub-populations. Population structure analysis revealed that rice accession was moderately structured based on FST value estimates. Analysis of molecular variance (AMOVA) and pairwise FST values showed significant differentiation among all the pairs of sub-population ranging from 0.152 to 0.222 suggesting that all the three subpopulations were significantly different from each other. AMOVA revealed that most of the variation in rice accession mainly occurred among individuals. The present study suggests that diverse germplasm of NE India could be used for the improvement of root and drought tolerance in rice breeding programmes.

Terpene Moiety Enhancement by Overexpression of Geranyl(geranyl) Diphosphate Synthase and Geraniol Synthase Elevates Monomeric and Dimeric Monoterpene Indole Alkaloids in Transgenic Catharanthus roseus.

Catharanthus roseus is the sole source of two of the most important anticancer monoterpene indole alkaloids (MIAs), vinblastine and vincristine and their precursors, vindoline and catharanthine. The MIAs are produced from the condensation of precursors derived from indole and terpene secoiridoid pathways. It has been previously reported that the terpene moiety limits MIA biosynthesis in C. roseus. Here, to overcome this limitation and enhance MIAs levels in C. roseus, bifunctional geranyl(geranyl) diphosphate synthase [G(G)PPS] and geraniol synthase (GES) that provide precursors for early steps of terpene moiety (secologanin) formation, were overexpressed transiently by agroinfiltration and stably by Agrobacterium-mediated transformation. Both transient and stable overexpression of G(G)PPS and co-expression of G(G)PPS+GES significantly enhanced the accumulation of secologanin, which in turn elevated the levels of monomeric MIAs. In addition, transgenic C. roseus plants exhibited increased levels of root alkaloid ajmalicine. The dimeric alkaloid vinblastine was enhanced only in G(G)PPS but not in G(G)PPS+GES transgenic lines that correlated with transcript levels of peroxidase-1 (PRX1) involved in coupling of vindoline and catharanthine into 3',4'-anhydrovinblastine, the immediate precursor of vinblastine. Moreover, first generation (T1) lines exhibited comparable transcript and metabolite levels to that of T0 lines. In addition, transgenic lines displayed normal growth similar to wild-type plants indicating that the bifunctional G(G)PPS enhanced flux toward both primary and secondary metabolism. These results revealed that improved availability of early precursors for terpene moiety biosynthesis enhanced production of MIAs in C. roseus at the whole plant level. This is the first report demonstrating enhanced accumulation of monomeric and dimeric MIAs including root MIA ajmalicine in C. roseus through transgenic approaches.

Redescription and Range Extension of Microhyla sholigari Dutta & Ray (Amphibia: Anura: Microhylidae) from South West India.

Microhyla sholigari is an endangered frog described in the year 2000. The original description was based on non-adult types and lacked information on several morphological characters, call structure, genetic material and photographs of the animal in life. The absence of such information posed challenges in field identification of this species. Since the original description, there is one other reported sighting of this species from Kerala in 2001. We encountered specimens that we confer to this species based on morphological similarity to the subadult holotype, from several new localities within and outside the Western Ghats of Karnataka. We here redescribe the species based on additional adult vouchers, provide molecular data, describe the advertisement call and report a range extension. Based on its current distribution, we assess the threat status of the species and suggest listing it as Least Concern according to IUCN Red List criteria. Our paper bridges an important gap in the knowledge of the genus Microhyla in India and highlights the importance of systematic surveys in documenting and understanding amphibian diversity in the region.

De Novo Sequencing and Analysis of Lemongrass Transcriptome Provide First Insights into the Essential Oil Biosynthesis of Aromatic Grasses.

Aromatic grasses of the genus Cymbopogon (Poaceae family) represent unique group of plants that produce diverse composition of monoterpene rich essential oils, which have great value in flavor, fragrance, cosmetic, and aromatherapy industries. Despite the commercial importance of these natural aromatic oils, their biosynthesis at the molecular level remains unexplored. As the first step toward understanding the essential oil biosynthesis, we performed de novo transcriptome assembly and analysis of C. flexuosus (lemongrass) by employing Illumina sequencing. Mining of transcriptome data and subsequent phylogenetic analysis led to identification of terpene synthases, pyrophosphatases, alcohol dehydrogenases, aldo-keto reductases, carotenoid cleavage dioxygenases, alcohol acetyltransferases, and aldehyde dehydrogenases, which are potentially involved in essential oil biosynthesis. Comparative essential oil profiling and mRNA expression analysis in three Cymbopogon species (C. flexuosus, aldehyde type; C. martinii, alcohol type; and C. winterianus, intermediate type) with varying essential oil composition indicated the involvement of identified candidate genes in the formation of alcohols, aldehydes, and acetates. Molecular modeling and docking further supported the role of identified protein sequences in aroma formation in Cymbopogon. Also, simple sequence repeats were found in the transcriptome with many linked to terpene pathway genes including the genes potentially involved in aroma biosynthesis. This work provides the first insights into the essential oil biosynthesis of aromatic grasses, and the identified candidate genes and markers can be a great resource for biotechnological and molecular breeding approaches to modulate the essential oil composition.

Stress-Induced Accumulation of DcAOX1 and DcAOX2a Transcripts Coincides with Critical Time Point for Structural Biomass Prediction in Carrot Primary Cultures (Daucus carota L.).

Stress-adaptive cell plasticity in target tissues and cells for plant biomass growth is important for yield stability. In vitro systems with reproducible cell plasticity can help to identify relevant metabolic and molecular events during early cell reprogramming. In carrot, regulation of the central root meristem is a critical target for yield-determining secondary growth. Calorespirometry, a tool previously identified as promising for predictive growth phenotyping has been applied to measure the respiration rate in carrot meristem. In a carrot primary culture system (PCS), this tool allowed identifying an early peak related with structural biomass formation during lag phase of growth, around the 4th day of culture. In the present study, we report a dynamic and correlated expression of carrot AOX genes (DcAOX1 and DcAOX2a) during PCS lag phase and during exponential growth. Both genes showed an increase in transcript levels until 36 h after explant inoculation, and a subsequent down-regulation, before the initiation of exponential growth. In PCS growing at two different temperatures (21°C and 28°C), DcAOX1 was also found to be more expressed in the highest temperature. DcAOX genes' were further explored in a plant pot experiment in response to chilling, which confirmed the early AOX transcript increase prior to the induction of a specific anti-freezing gene. Our findings point to DcAOX1 and DcAOX2a as being reasonable candidates for functional marker development related to early cell reprogramming. While the genomic sequence of DcAOX2a was previously described, we characterize here the complete genomic sequence of DcAOX1.

Substance Abuse amongst the Street-children in Guwahati City, Assam.

BACKGROUND: The nature of continuous exposure to the street and its associated life-styles make street children vulnerable to the use of psychoactive substances. AIMS: The aim of the present study is to study some social factors of street children in Guwahati city and to ascertain the substance use behavior of the street children. SUBJECTS AND METHODS: A population based cross-sectional study conducted during September 2008 to August 2009 among 215 street children between the ages of 5 and 18 years of Guwahati City Assam. The main outcome measures were substance use and its related risk factors prevalent among street children. The data collected were analyzed in Microsoft Office and percentages and Chi-square tests were used to analyze the variables. RESULTS: Around 174/215 (80.9%) of study participants were substance abusers. It is noteworthy that as the age increases substance use was more common when compared to younger age group. The risk of substance abuse was 1.26 times relatively higher among those who had never been to school and 1.12 times more common in those from a joint family when compared to others. However the correlations were not found to be statistically significant. Substance abuse was 1.19 times more common in case of deaths of both parents and the association was found to be statistically significant (P = 0.02). Presence of step parents and substance use in the family was seen to be a risk factor for substance abuse and the association was highly significant (P < 0.001). The association of substance abuse with duration of street life was found to be highly significant. Majority of the substance users 152/174 (87.4%) were in the habit of sniffing glue and this was followed by smoking 147/174 (84.5%). CONCLUSION: Substance abuse is an important concern affecting street children. Street and its associated life-styles make street children vulnerable to the use of psychoactive substances. Non- government organizations and Government should come forward to curb this problem and save millions of vulnerable lives.

Association studies of dormancy and cooking quality traits in direct-seeded indica rice.

Association analysis was applied to a panel of accessions of Assam rice (indica) using 98 SSR markers for dormancy-related traits and cooking quality. Analysis of population structure revealed 10 subgroups in the population. The mean r(2) and D' value for all intrachromosomal loci pairs was 0.24 and 0.51, respectively. Linkage disequilibrium between linked markers decreased with distance. Marker-trait associations were investigated using the unified mixed-model approach, considering both population structure (Q) and kinship (K). Genome-wide scanning, detected a total of seven significant marker-trait associations (P < 0.01), with the R(2) values ranging from 12.0 to 18.0%. The significant marker associations were for grain dormancy (RM27 on chromosome 2), α-amylase activity (RM27 and RM234 on chromosomes 2 and 7, respectively), germination (RM27 and RM106 on chromosome 2), amylose (RM282 on chromosome 3) and grain length elongation ratio (RM142 on chromosome 4). The present study revealed the association of marker RM27 with traits like dormancy, α-amylase activity and germination. Simple correlation analysis of these traits revealed that these traits were positively correlated with each other and this marker may be useful for simultaneous improvement of these traits. The study indicates the presence of novel QTLs for a few traits under consideration. The study reveals association of traits like dormancy, α-amylase activity, germination, amylose content, grain length elongation ratio with SSR markers indicating the feasibility of undertaking association analysis in conjunction with germplasm characterization.

Brevibacillus laterosporus strain BPM3, a potential biocontrol agent isolated from a natural hot water spring of Assam, India.

A bacterial strain designated as BPM3 isolated from mud of a natural hot water spring of Nambar Wild Life Sanctuary, Assam, India, strongly inhibited growth of phytopathogenic fungi (Fusarium oxysporum f. sp. ciceri, F. semitectum, Magnaporthe grisea and Rhizoctonia oryzae) and gram-positive bacterium (Staphylococcus aureus). The maximum growth and antagonistic activity was recorded at 30°C, pH 8.5 when starch and peptone were amended as carbon and nitrogen sources, respectively. In greenhouse experiment, this bacterium (BPM3) suppressed blast disease of rice by 30-67% and protected the weight loss by 35-56.5%. The maximum disease protection (67%) and weight loss protection (56.5%) were recorded when the bacterium was applied before 2 days of the pathogen inoculation. Antifungal and antibacterial compounds were isolated from the bacterium which also inhibited the growth of these targeted pathogens. The compounds were purified and on spectroscopic analysis of a purified fraction having R(f) 0.22 which showed strong antifungal and antibacterial activity indicated the presence of C-H, carbonyl group, dimethyl group, -CH(2) and methyl group. The bacterium was characterized by morphological, biochemical and molecular approaches and confirmed that the strain BPM3 is Brevibacillus laterosporus.

The study of bacterial flora of different types in hospital waste: evaluation of waste treatment at Aiims Hospital, New Delhi.

Bio-medical waste management rules were formulated in response to the worldwide public concern over medical waste. The practice of separation into different types of waste in health care institutes should be evaluated more scientifically. Due to a lack of data from the Indian sub-continent, this study was initiated at a tertiary care hospital. Samples were collected from different types of waste at the hospital, at different time intervals, for microbiological evaluation. The results reveal that the microbial flora isolated from infectious waste and general waste from the hospital are similar. The samples from general waste in this study reveal many types of pathogens. The bacteria present in the waste initially was low in quantity, but they replicated rapidly over time so that significant numbers were detected by 24 hours, due to environmental factors which were favorable for growth during this period. This study strongly suggests that waste should be removed from the hospital within 24 hours of its generation to prevent environmental contamination caused by any accidental spillage of waste. General waste generated in the hospital should be treated similar to infectious waste, as it can be equally hazardous.

Molecular modeling of a Leishmania antigen eIF-4A: identification of a potential epitope implicated in the adjuvant effect.

In leishmaniasis, the development of an effective vaccine depends on its capacity to elicit Th1 immune responses. Despite many approaches, recent vaccines do not induce sufficient levels of protection and long-term memory. To overcome this problem, vaccines are used with adjuvants that drive immunity towards Th1 and enhance endogenous production of IL-12, a Th1-promoting cytokine. Although exogenous IL-12 may act as an effective adjuvant, it has an elevated cost and toxic effects. Therefore, it is important to develop cheap and safer adjuvants that trigger endogenous IL-12. Of particular interest is LmeIF a unique Leishmania protein that provides significant adjuvant effects by stimulating high IL-12 production. This investigation was designed to identify the structural factors responsible for the adjuvant effects of LmeIF by establishing the 3D models of LmeIF and MueIF (mouse) by homology modeling based on the X-ray structure of their homologs in yeast and comparing their stereo-electronic properties. The molecular electrostatic potential was computed around each model and used to localize the active site and the most different amino acids between LmeIF and MueIF. Sequence alignment of LmeIF with eIF-4 from other species showed three residues (Q186, A189, E214) in the active site which were peculiar to the Leishmania protein. Long MD simulation was carried out on LmeIF fragment 129-261 to compare its folding with the native protein. Despite a high degree of sequence similarity with different species, we have identified in LmeIF a set of residues unique to the protozoan parasite Leishmania which may be potentially responsible for its adjuvant property. Using LmeIF model, a plausible surface region for binding with its receptor was also identified.

Plausible interaction of an alpha-fetoprotein cyclopeptide with the G-protein-coupled receptor model GPR30: docking study by molecular dynamics simulated annealing.

In this manuscript, the procedure of molecular dynamics simulated annealing is applied to locate a probable receptor and binding site of a cyclicpeptide that inhibits estrogen-stimulated proliferation of breast cancer. The hydrophilic cyclopeptide EMTOVNOGQ (O = 4-hydroxyproline), derived from alpha-fetoprotein, is an inhibitor of estrogen-stimulated proliferation of human breast cancer. This peptide has been shown to act through a mechanism different from that of estrogen; however, its receptor is unknown. We report computer experiments that suggest that this peptide may execute its actions by interacting with GPR30, a G-protein-coupled receptor. The subject of this work is the simulation, by molecular dynamics simulated annealing, of the interaction of cyclopeptide EMTOVNOGQ with receptor GPR30 protein. A conformational analysis of the cyclopeptide was undertaken and the final structure was docked on several sites of the GPR30 3D model. Our results show that the cyclopeptide interacts on the pocket located between TM6 and TM7 transmembrane helices of the G-protein, triggering a slight conformational change in the secondary structure of the receptor in the complex. Based on differences in accessible surface areas between GPR30 and its ligand, the residues in the interaction zone were identified. The cyclopeptide is stabilized in the active site by forming a network of hydrogen bonds between Glu, Thr, (1)Pro(OH) and GLn residues of the ligand and Arg-259, Cys-271, Asn-316, Asn-320 and Tyr-324 of the G-protein. Moreover, the study of the electrostatic surface potential on the GPR30 receptor shows that the active site is more positively charged than the other sites. Our modeling indicates a plausible interaction of the cyclopeptide with the seven transmembrane GPR30 protein. This may have profound implications for the treatment of breast cancer.

Knowledge, attitude and practices towards HIV among nurses in a tertiary care teaching hospital: two decades after the discovery.

Accidental transmission of HIV infection to health care workers during occupational exposure is a real threat today. The first such case in India has been documented by NACO recently. Adequate knowledge about the disease and practice of safety measures are our best bet to reduce such transmission. A survey was carried out amongst over 500 nurses in a tertiary care referral hospital in Delhi to assess their knowledge, attitude and practices towards HIV/AIDS. While overall knowledge was satisfactory, there were gaping holes in vital areas. The conversion of their theoretical knowledge into safe practices was shockingly poor. It was due to attitude problems as much as inadequate supplies. High incidence of accidental exposures in the near past and complete ignorance of post-exposure prophylaxis guidelines was another highlight of this study. Despite tremendous efforts put in by the Government as well as various Non-Governmental Organizations, we are completely ill equipped to fight the menace of occupational HIV transmission. In order to fight this menace, "safe practices" have to be made a "way of life" for HCWs. Our health care planners need to take note of it and our teaching and training programmes need complete re-orientation to achieve this goal.

Physical characterization of the homoeologous group 5 chromosomes of wheat in terms of rice linkage blocks, and physical mapping of some important genes.

The wheat homoeologous Group 5 chromosomes were characterized physically in terms of rice linkage blocks using a deletion mapping approach. All three chromosomes, 5A, 5B, and 5D, were shown to have a similar structure, apart from the 4A-5A translocation on the distal end of chromosome arm 5AL. The physical mapping of rice markers on the deletion lines revealed that the whole of rice chromosome 9 is syntenous to a large block, proximal to the centromere, on the long arm. Likewise, a small segment of the distal end of the long arm showed conserved synteny with the distal one-third end of the long arm of rice chromosome 3. In between those conserved regions, there is a region on the long arm of the Group 5 chromosomes which shows broken synteny. The proximal part of the short arms of the Group 5 chromosomes showed conserved synteny with a segment of the short arm of rice chromosome 11 and the distal ends showed conserved synteny with a segment of rice chromosome 12. The physical locations of flowering time genes (Vrn and earliness per se) and the gene for grain hardness (Ha) on the Group 5 chromosomes were determined. These results indicate that comparative mapping using the deletion mapping approach is useful in the study of genome relationships, the physical location of genes, and can determine the appropriate gene cloning strategy.

DNA bending and sugar switching.

Abstract Using high frequency antiphase NMR spectroscopy and computer simulations of the antiphase spectra, we studied the equlibria in the sugar conformations in the DNA duplex 11-mer containing the AAA tract surrounded by cytosines. We demonstrate that at the 3'-end of the A-tract, the sugar switches from the common S-conformer (B-like form) to the N-conformer (A-like form) with the probability of 50-60%, thus creating a purine-pyrimidine step with heteronomous characteristics. The presence of this local B-A junction in one strand leads to compression of the interphosphate distance in this strand. We calculate the effect of this sugar switch on the helical parameters that are related to DNA bending. Finally, we suggest that the heteronomous deformation present in the A(n)C motif of unbound DNA duplexes might be the initial recognition site for proteins which bind to such junctions; and that in A(n)C stretches, DNA bending is a complicated dynamic process, i.e., locally noncanonical N conformers of the sugar phosphate backbone mix in with the B-like S conformers leading to bending.