Occurrence and distribution of compound microsatellites in the genomes of three economically important virus families.

Microsatellites are nonrandom hypervariable iterations of one to six nucleotides, existing across the coding as well as noncoding regions of virtually all known genomes, arising primarily due to polymerase slippage and unequal crossing over during replication events. Two or more perfect microsatellites located in close proximity form compound microsatellites. We studied the distribution of compound microsatellites in 118 ssDNA virus genomes belonging to three economically important virus families, namely Anelloviridae, Circoviridae, and Parvoviridae, known to predominantly infect livestock and humans. Among these virus families, 0-58.49% of perfect microsatellites were involved in the formation of compound microsatellites, the majority being located in the coding regions. No clear relationship existed between the genomic features (genome size and GC%) and compound microsatellite characteristics (relative abundance and relative density). The majority of the compound microsatellites resulted from di-SSR couples. A strong positive relationship was observed between the maximum distance value and length of compound microsatellite, percentage of microsatellites involved in the compound microsatellite formation, and relative microsatellite density. The degree of variability among microsatellite characteristics studied was largely a species-specific phenomenon. A major proportion of compound microsatellites was represented by similar motif combinations. The findings of the present study will help in better understanding of the structural, functional, and evolutionary role of compound microsatellites prevailing in the smaller genomes.

Next generation sequencing-based emerging trends in molecular biology of gastric cancer.

Gastric cancer (GC) is one of the leading causes of cancer related mortality in the world. Being asymptomatic in nature till advanced stage, diagnosis of gastric cancer becomes difficult in early stages of the disease. The onset and progression of gastric cancer has been attributed to multiple factors including genetic alterations, epigenetic modifications, Helicobacter pylori and Epstein-Barr Virus (EBV) infection, and dietary habits. Next Generation Sequencing (NGS) based approaches viz. Whole Genome Sequencing (WGS), Whole Exome Sequencing (WES), RNA-Seq, and targeted sequencing have expanded the knowledge base of molecular pathogenesis of gastric cancer. In this review, we highlight recent NGS-based advances covering various genetic alterations (Microsatellite Instability, Single Nucleotide Variations, and Copy Number Variations), epigenetic changes (DNA methylation, histone modification, microRNAs) and differential gene expression during gastric tumorigenesis. We also briefly discuss the current and future potential biomarkers, drugs and therapeutic approaches available for the management of gastric cancer.

An improved method suitable for isolation of high-quality metagenomic DNA from diverse soils.

Standardization of metagenomic DNA extraction protocol is a pre-requisite for a successful metagenomic study aiming to screen and exploit the variety of microorganisms inhabiting a particular soil environment. Six methods reported earlier were used for isolation of metagenomic DNA in the present study. These methods suffered with regard to either poor yield or quality of DNA. Therefore, we developed an improved method for isolation of high-molecular weight and good quality metagenomic DNA from different soil samples. Our protocol combines the enzymatic (lysozyme and proteinase K) and chemical (CTAB and CaCl2) strategies to ensure efficient cell lysis and use of PEG and isopropanol for precipitation of humic impurities-free DNA. Our improved method gave high yield of good quality metagenomic DNA from diverse soils collected from garden, domestic waste dumping site, cellulose waste dumping site, sewage site, and tannery waste site. The good quality of the metagenomic DNA was evident by spectrophotometry data, PCR amplification of 16S rRNA gene and restriction digestion.

Correction: Genetic Dissection of Drought and Heat Tolerance in Chickpea through Genome-Wide and Candidate Gene-Based Association Mapping Approaches.

[This corrects the article DOI: 10.1371/journal.pone.0096758.].

DeepSAGE based differential gene expression analysis under cold and freeze stress in seabuckthorn (Hippophae rhamnoides L.).

Seabuckthorn (Hippophae rhamnoides L.), an important plant species of Indian Himalayas, is well known for its immense medicinal and nutritional value. The plant has the ability to sustain growth in harsh environments of extreme temperatures, drought and salinity. We employed DeepSAGE, a tag based approach, to identify differentially expressed genes under cold and freeze stress in seabuckthorn. In total 36.2 million raw tags including 13.9 million distinct tags were generated using Illumina sequencing platform for three leaf tissue libraries including control (CON), cold stress (CS) and freeze stress (FS). After discarding low quality tags, 35.5 million clean tags including 7 million distinct clean tags were obtained. In all, 11922 differentially expressed genes (DEGs) including 6539 up regulated and 5383 down regulated genes were identified in three comparative setups i.e. CON vs CS, CON vs FS and CS vs FS. Gene ontology and KEGG pathway analysis were performed to assign gene ontology term to DEGs and ascertain their biological functions. DEGs were mapped back to our existing seabuckthorn transcriptome assembly comprising of 88,297 putative unigenes leading to the identification of 428 cold and freeze stress responsive genes. Expression of randomly selected 22 DEGs was validated using qRT-PCR that further supported our DeepSAGE results. The present study provided a comprehensive view of global gene expression profile of seabuckthorn under cold and freeze stresses. The DeepSAGE data could also serve as a valuable resource for further functional genomics studies aiming selection of candidate genes for development of abiotic stress tolerant transgenic plants.

Genome wide survey of microsatellites in ssDNA viruses infecting vertebrates.

Microsatellites or Simple Sequence Repeats (SSRs) are tandem iterations of one to six base pairs, non-randomly distributed throughout prokaryotic and eukaryotic genomes. Limited knowledge is available about distribution of microsatellites in single stranded DNA (ssDNA) viruses, particularly vertebrate infecting viruses. We studied microsatellite distribution in 118 ssDNA virus genomes belonging to three families of vertebrate infecting viruses namely Circoviridae, Parvoviridae, and Anelloviridae, and found that microsatellites constitute an important component of these virus genomes. Mononucleotide repeats were predominant followed by dinucleotide and trinucleotide repeats. A strong positive relationship existed between number of mononucleotide repeats and genome size among all the three virus families. A similar relationship existed for the occurrence of DTTPH (di-, tri-, tetra-, penta- and hexa-nucleotide) repeats in the families Anelloviridae and Parvoviridae only. Relative abundance and relative density of mononucleotide repeats showed a strong positive relationship with genome size in Circoviridae and Parvoviridae. However, in the case of DTTPH repeats, these features showed a strong relationship with genome size in Circoviridae only. On the other hand, relative microsatellite abundance and relative density of mononucleotide repeats were negatively correlated with GC content (%) in Parvoviridae genomes. On the basis of available annotations, our analysis revealed maximum occurrence of mononucleotide as well as DTTPH repeats in the coding regions of these virus genomes. Interestingly, after normalizing the length of the coding and non-coding regions of each virus genome, we found relative density of microsatellites much higher in the non-coding regions. We understand that the present study will help in the better characterization of the stability, genome organization and evolution of these virus classes and may provide useful leads to decipher the etiopathogenesis of these viruses.

Allele diversity for abiotic stress responsive candidate genes in chickpea reference set using gene based SNP markers.

Chickpea is an important food legume crop for the semi-arid regions, however, its productivity is adversely affected by various biotic and abiotic stresses. Identification of candidate genes associated with abiotic stress response will help breeding efforts aiming to enhance its productivity. With this objective, 10 abiotic stress responsive candidate genes were selected on the basis of prior knowledge of this complex trait. These 10 genes were subjected to allele specific sequencing across a chickpea reference set comprising 300 genotypes including 211 genotypes of chickpea mini core collection. A total of 1.3 Mbp sequence data were generated. Multiple sequence alignment (MSA) revealed 79 SNPs and 41 indels in nine genes while the CAP2 gene was found to be conserved across all the genotypes. Among 10 candidate genes, the maximum number of SNPs (34) was observed in abscisic acid stress and ripening (ASR) gene including 22 transitions, 11 transversions and one tri-allelic SNP. Nucleotide diversity varied from 0.0004 to 0.0029 while polymorphism information content (PIC) values ranged from 0.01 (AKIN gene) to 0.43 (CAP2 promoter). Haplotype analysis revealed that alleles were represented by more than two haplotype blocks, except alleles of the CAP2 and sucrose synthase (SuSy) gene, where only one haplotype was identified. These genes can be used for association analysis and if validated, may be useful for enhancing abiotic stress, including drought tolerance, through molecular breeding.

Genetic dissection of drought and heat tolerance in chickpea through genome-wide and candidate gene-based association mapping approaches.

To understand the genetic basis of tolerance to drought and heat stresses in chickpea, a comprehensive association mapping approach has been undertaken. Phenotypic data were generated on the reference set (300 accessions, including 211 mini-core collection accessions) for drought tolerance related root traits, heat tolerance, yield and yield component traits from 1-7 seasons and 1-3 locations in India (Patancheru, Kanpur, Bangalore) and three locations in Africa (Nairobi, Egerton in Kenya and Debre Zeit in Ethiopia). Diversity Array Technology (DArT) markers equally distributed across chickpea genome were used to determine population structure and three sub-populations were identified using admixture model in STRUCTURE. The pairwise linkage disequilibrium (LD) estimated using the squared-allele frequency correlations (r2; when r2<0.20) was found to decay rapidly with the genetic distance of 5 cM. For establishing marker-trait associations (MTAs), both genome-wide and candidate gene-sequencing based association mapping approaches were conducted using 1,872 markers (1,072 DArTs, 651 single nucleotide polymorphisms [SNPs], 113 gene-based SNPs and 36 simple sequence repeats [SSRs]) and phenotyping data mentioned above employing mixed linear model (MLM) analysis with optimum compression with P3D method and kinship matrix. As a result, 312 significant MTAs were identified and a maximum number of MTAs (70) was identified for 100-seed weight. A total of 18 SNPs from 5 genes (ERECTA, 11 SNPs; ASR, 4 SNPs; DREB, 1 SNP; CAP2 promoter, 1 SNP and AMDH, 1SNP) were significantly associated with different traits. This study provides significant MTAs for drought and heat tolerance in chickpea that can be used, after validation, in molecular breeding for developing superior varieties with enhanced drought and heat tolerance.

Hypobaric hypoxia-mediated protein expression in plasma of susceptible & tolerant rats.

BACKGROUND & OBJECTIVES: Low availability of oxygen at high altitudes has a great impact on the human life processes. There is a widespread interest and need to find out protein(s) that are possibly involved in mediating tolerance to hypobaric hypoxia. We undertook this study to identify and characterize protein expression in plasma of hypoxia susceptible and tolerant rats. METHODS: Male albino Sprague Dawley rats were segregated into susceptible and tolerant groups on the basis of their gasping time when exposed to simulated hypobaric hypoxia of 32,000 ft (9,754 m) at 32°C. Comparative proteome profiling of blood plasma of hypoxia susceptible and tolerant individuals was performed using 2-dimentional (2-D) gel electrophoresis. RESULTS: Three proteins with higher expression levels were selected separately from tolerant and susceptible samples. Characterization of these proteins from tolerant sample using MALDI-TOF/TOF and MASCOT search indicated their homology with two different super-families viz. NADB-Rossmann superfamily (Rab GDP dissociation inhibitor ß) and Transferrin superfamily (two Serotransferrins), having potential role in imparting tolerance against hypoxia. Three high level upregulated proteins were characterized from blood plasma of hypoxia susceptible animals showing similarity with threonine tRNA ligase (mitochondrial), carbohydrate sulphotransferase 7 and aspartate tRNA ligase (cytoplasmic) that play a role in ATP binding, carbohydrate metabolism and protein biosynthesis, respectively. INTERPRETATION & CONCLUSIONS: Our results indicated that rats segregated into hypoxia sensitive and tolerant based on their gasping time showed differential expression of proteins in blood plasma. Characterization of these differentially expressed proteins will lead to better understanding of molecular responses occurring during hypoxia and subsequently development of biomarkers for categorization of hypoxia susceptible and tolerant individuals.

Implication of microsatellite instability in human gastric cancers.

Microsatellite instability, one of the phenomena implicated in gastric cancer, is mainly associated with the expansion or contraction of microsatellite sequences due to replication errors caused most frequently by mutations in the mismatch repair (MMR) and tumour suppressor genes. Tumours exhibiting microsatellite instability are proven to have truncated products resulting from frequent mutations in mononucleotide or dinucleotide runs in coding and non-coding regions of the targeted genes. Epigenetic changes like hypermethylation of the promoter region of MMR genes as well as gene silencing are also responsible for the microsatellite instability phenotypes. Assessing microsatellite instability in tumours has proved to be an efficient tool for the prognosis of various cancers including colorectal and gastric cancers. Such tumours are characterized by distinct clinicopathological profiles. Biotic agents like Epstein Barr Virus and H. pylori along with other factors like family history, diet and geographical location also play an important role in the onset of gastric carcinogenesis. Instability of mitochondrial DNA has also been investigated and claimed to be involved in the occurrence of gastric cancers in humans. Development of simplified but robust and reproducible microsatellite instability based molecular tools promises efficient prognostic assessment of gastric tumours.

Expressed sequence tag based identification and expression analysis of some cold inducible elements in seabuckthorn (Hippophae rhamnoides L.).

A cDNA library was constructed from the mature leaves of seabuckthorn (Hippophae rhamnoides). Expressed Sequence Tags (ESTs) were generated by single pass sequencing of 4500 cDNA clones. We submitted 3412 ESTs to dbEST of NCBI. Clustering of these ESTs yielded 1665 unigenes comprising of 345 contigs and 1320 singletons. Out of 1665 unigenes, 1278 unigenes were annotated by similarity search while the remaining 387 unannotated unigenes were considered as organism specific. Gene Ontology (GO) analysis of the unigene dataset showed 691 unigenes related to biological processes, 727 to molecular functions and 588 to cellular component category. On the basis of similarity search and GO annotation, 43 unigenes were found responsive to biotic and abiotic stresses. To validate this observation, 13 genes that are known to be associated with cold stress tolerance from previous studies in Arabidopsis and 3 novel transcripts were examined by Real time RT-PCR to understand the change in expression pattern under cold/freeze stress. In silico study of occurrence of microsatellites in these ESTs revealed the presence of 62 Simple Sequence Repeats (SSRs), some of which are being explored to assess genetic diversity among seabuckthorn collections. This is the first report of generation of transcriptome data providing information about genes involved in managing plant abiotic stress in seabuckthorn, a plant known for its enormous medicinal and ecological value.

Combining QTL mapping and transcriptome profiling of bulked RILs for identification of functional polymorphism for salt tolerance genes in rice (Oryza sativa L.).

Identification of genes for quantitative traits is difficult using any single approach due to complex inheritance of the traits and limited resolving power of the individual techniques. Here a combination of genetic mapping and bulked transcriptome profiling was used to narrow down the number of differentially expressed salt-responsive genes in rice in order to identify functional polymorphism of genes underlying the quantitative trait loci (QTL). A population of recombinant inbred lines (RILs) derived from cross between salt-tolerant variety CSR 27 and salt-sensitive variety MI 48 was used to map QTL for salt ion concentrations in different tissues and salt stress susceptibility index (SSI) for spikelet fertility, grain weight, and grain yield. Eight significant QTL intervals were mapped on chromosomes 1, 8, and 12 for the salt ion concentrations and a QTL controlling SSI for spikelet fertility was co-located in one of these intervals on chromosome 8. However, there were total 2,681 genes in these QTL intervals, making it difficult to pinpoint the genes responsible for the functional differences for the traits. Similarly, transcriptome profiling of the seedlings of tolerant and sensitive parents grown under control and salt-stress conditions showed 798 and 2,407 differentially expressed gene probes, respectively. By analyzing pools of RNA extracted from ten each of extremely tolerant and extremely sensitive RILs to normalize the background noise, the number of differentially expressed genes under salt stress was drastically reduced to 30 only. Two of these genes, an integral transmembrane protein DUF6 and a cation chloride cotransporter, were not only co-located in the QTL intervals but also showed the expected distortion of allele frequencies in the extreme tolerant and sensitive RILs, and therefore are suitable for future validation studies and development of functional markers for salt tolerance in rice to facilitate marker-assisted breeding.

Development of EST-based new SSR markers in seabuckthorn.

EST-based SSR markers were developed by screening a collection of 1584 clustered ESTs of seabuckthorn (Hippophae rhamnoides). PCR primers were designed for the amplification of 30 microsatellite loci. Two to five allelic bands were displayed by nine primer pairs in H. rhamnoides genotypes and by eleven primer pairs in H. salicifolia genotypes. None of the thirty primer pairs detected polymorphism in H. tibetana genotypes. Considering the high polymorphism detected in the tested genotypes and their direct origin from the genic regions, these EST-SSR markers hold immense promise in seabuckthorn genome analysis, molecular breeding and population genetics.

Genome-wide analysis of conservation and divergence of microsatellites in rice.

Studies on microsatellite distribution and divergence in related genomes contribute towards understanding of genome evolution in eukaryotes. Despite the availability of whole genome sequences of four rice genomes, occurrence and significance of microsatellites in the rice genome has remained a relatively unexplored area of research. We have aligned genomes of two rice subspecies i.e. indica and japonica to understand the trends of microsatellite conservation and divergence in the rice genome. Nearly 62% of the indica microsatellites were also found in the japonica genome. Occurrence of microsatellites showed a negative association with that of retrotransposons. Microsatellites repeat unit length and sequence showed direct influence on the microsatellite locus length. Further, microsatellite allele length was also influenced by the sequence characteristics of the neighbouring regions. CCG repeats were most conserved microsatellite sequences across the different syntenic regions in the two rice genomes and often showed association with CpG islands. Our study suggested that microsatellite distribution is not only governed by a balance between replication slippage and point mutations as proposed earlier, but also by the microsatellite motif sequence and characteristics of microsatellite neighbouring regions in the genome. Thus, this study is likely to prove an important reference for understanding the process of microsatellite evolution and dynamics in the two rice subspecies.

A novel orf108 co-transcribed with the atpA gene is associated with cytoplasmic male sterility in Brassica juncea carrying Moricandia arvensis cytoplasm.

Mitochondrial atpA transcripts were examined in cytoplasmic male sterile (CMS) and fertility restorer lines of CMS (Moricandia arvensis) Brassica juncea. Male sterile flowers had longer atpA transcripts than male fertiles. The mitochondrial atpA region of the CMS line was cloned and sequenced. The 5' and 3' ends of the atpA transcripts of the CMS and the fertility restorer lines were mapped and full-length transcripts were cloned and sequenced. A novel orf108 (open reading frame 108) co-transcribed with the atpA gene was found in the male sterile flowers. In the fertility restorer line, the transcript was cleaved within orf108 to yield monocistronic atpA transcripts.

Mining microsatellites in eukaryotic genomes.

During recent decades, microsatellites have become the most popular source of genetic markers. More recently, the availability of enormous sequence data for a large number of eukaryotic genomes has accelerated research aimed at understanding the origin and functions of microsatellites and searching for new applications. This review presents recent developments of in silico mining of microsatellites to reveal various facets of the distribution and dynamics of microsatellites in eukaryotic genomes. Two aspects of microsatellite search strategies--using a suitable search tool and accessing a relevant microsatellite database--have been explored. Judicious microsatellite mining not only helps in addressing biological questions but also facilitates better exploitation of microsatellites for diverse applications.

Microsatellite motifs with moderate GC content are clustered around genes on Arabidopsis thaliana chromosome 2.

Microsatellites, arrays of 1-6 bp sequences, are abundant in almost all the eukaryotic genomes. Their distribution in the genome is widely accepted to be differential and non random along the axis of the chromosomes. Arabidopsis thaliana genome is dominated by mononucleotide repeats, (A)n being the most abundant motif. In total, 39 microsatellite motifs extended to more than 100 bp in length. Of these, 8 loci are devoid of any gene in their proximity. (AG)n is the most abundant motif among longer repeats. The non-random distribution of microsatellite in the genome is reflected as occurrence of microsatellite clusters in the genome. In total, 3400 microsatellite clusters have been identified in the Arabidopsis genome. Chromosome 2, which is 19.7 Mb long, harbors 550 clusters accommodating 29% of all the microsatellites present on this chromosome. Further, 409 of the 6239 genes on chromosome 2 are associated with 323 microsatellite clusters. Motifs like (AGG)n and (ACT)n, show preferential accommodation in clusters that overlap with genes. Among all the microsatellite clusters that show an overlap with genes, 80% of the clusters show an overlap in such a way that the cluster ends beyond the 3'-end of the gene or starts before the 5'-end of a gene. Genes with diverse functions show association with the clusters. However, not all members of a gene family show similar associations.

EuMicroSatdb: a database for microsatellites in the sequenced genomes of eukaryotes.

BACKGROUND: Microsatellites have immense utility as molecular markers in different fields like genome characterization and mapping, phylogeny and evolutionary biology. Existing microsatellite databases are of limited utility for experimental and computational biologists with regard to their content and information output. EuMicroSatdb (Eukaryotic MicroSatellite database) http://ipu.ac.in/usbt/EuMicroSatdb.htm is a web based relational database for easy and efficient positional mining of microsatellites from sequenced eukaryotic genomes. DESCRIPTION: A user friendly web interface has been developed for microsatellite data retrieval using Active Server Pages (ASP). The backend database codes for data extraction and assembly have been written using Perl based scripts and C++. Precise need based microsatellites data retrieval is possible using different input parameters like microsatellite type (simple perfect or compound perfect), repeat unit length (mono- to hexa-nucleotide), repeat number, microsatellite length and chromosomal location in the genome. Furthermore, information about clustering of different microsatellites in the genome can also be retrieved. Finally, to facilitate primer designing for PCR amplification of any desired microsatellite locus, 200 bp upstream and downstream sequences are provided. CONCLUSION: The database allows easy systematic retrieval of comprehensive information about simple and compound microsatellites, microsatellite clusters and their locus coordinates in 31 sequenced eukaryotic genomes. The information content of the database is useful in different areas of research like gene tagging, genome mapping, population genetics, germplasm characterization and in understanding microsatellite dynamics in eukaryotic genomes.

Contribution of germline BRCA1 and BRCA2 sequence alterations to breast cancer in Northern India.

BACKGROUND: A large number of distinct mutations in the BRCA1 and BRCA2 genes have been reported worldwide, but little is known regarding the role of these inherited susceptibility genes in breast cancer risk among Indian women. We investigated the distribution and the nature of BRCA1 and BRCA2 germline mutations and polymorphisms in a cohort of 204 Indian breast cancer patients and 140 age-matched controls. METHOD: Cases were selected with regard to early onset disease (< or =40 years) and family history of breast and ovarian cancer. Two hundred four breast cancer cases along with 140 age-matched controls were analyzed for mutations. All coding regions and exon-intron boundaries of the BRCA1 and BRCA2 genes were screened by heteroduplex analysis followed by direct sequencing of detected variants. RESULTS: In total, 18 genetic alterations were identified. Three deleterious frame-shift mutations (185delAG in exon 2; 4184del4 and 3596del4 in exon 11) were identified in BRCA1, along with one missense mutation (K1667R), one 5'UTR alteration (22C>G), three intronic variants (IVS10-12delG, IVS13+2T>C, IVS7+38T>C) and one silent substitution (5154C>T). Similarly three pathogenic protein-truncating mutations (6376insAA in exon 11, 8576insC in exon19, and 9999delA in exon 27) along with one missense mutation (A2951T), four intronic alterations (IVS2+90T>A, IVS7+75A>T, IVS8+56C>T, IVS25+58insG) and one silent substitution (1593A>G) were identified in BRCA2. Four previously reported polymorphisms (K1183R, S1613G, and M1652I in BRCA1, and 7470A>G in BRCA2) were detected in both controls and breast cancer patients. Rare BRCA1/2 sequence alterations were observed in 15 out of 105 (14.2%) early-onset cases without family history and 11.7% (4/34) breast cancer cases with family history. Of these, six were pathogenic protein truncating mutations. In addition, several variants of uncertain clinical significance were identified. Among these are two missense variants, one alteration of a consensus splice donor sequence, and a variant that potentially disrupts translational initiation. CONCLUSION: BRCA1 and BRCA2 mutations appear to account for a lower proportion of breast cancer patients at increased risk of harboring such mutations in Northern India (6/204, 2.9%) than has been reported in other populations. However, given the limited extent of reported family history among these patients, the observed mutation frequency is not dissimilar from that reported in other cohorts of early onset breast cancer patients. Several of the identified mutations are unique and novel to Indian patients.

Different antioxidants status, total antioxidant power and free radicals in essential hypertension.

Hypertension is a multi-factorial process, prevalent in developed as well as in developing countries. Different antioxidants and free radicals play an important role in cardiovascular system. In present study, total antioxidant power in terms of FRAP (ferric reducing activity of plasma), free radicals and different antioxidants have been studied in essential hypertensives (n = 50) and normal subjects (n = 50). Levels of total cholesterol, low-density lipids-cholesterol, malonialdehyde, very low-density lipids (VLDL), uric acid, plasma homocysteine and low-density lipids (LDL), were significantly higher in hypertensives as compared to normotensive. HDL-cholesterol, SOD, GPx, reduced glutahione, total glutathione, oxidized glutathione, total thiols, protein thiols, non protein thiols, RNI, total antioxidant power, vitamin A, ascorbic acid and glutahione-S-transferase (GST) were decreased significantly in normotensive. We observed significantly low nitric oxide levels in hypertensive patients. No correlation was observed between severity of disease and plasma nitric oxide levels. There was a significant decrease in plasma FRAP value in essential hypertensives as compared to normotensive controls, which showed a negative correlation with diastolic blood pressure. In conclusion, our study revealed that there was a consistent significant difference between essential hypertensives versus controls with respect to most of the parameters. These complex changes are consistent in the view that essential hypertension is associated with an abnormal level of antioxidant status compared to normal response to oxidative stress or both.