Multifaceted Role of Nanomaterials in Modulating In Vitro Seed Germination, Plant Morphogenesis, Metabolism and Genetic Engineering.

The agricultural practices of breeding, farm management and cultivation have improved production, to a great extent, in order to meet the food demands of a growing population. However, the newer challenges of climate change, global warming, and nutritional quality improvement will have to be addressed under a new scenario. Plant biotechnology has emerged as a reliable tool for enhancing crop yields by protecting plants against insect pests and metabolic engineering through the addition of new genes and, to some extent, nutritional quality improvement. Plant tissue culture techniques have provided ways for the accelerated clonal multiplication of selected varieties with the enhanced production of value-added plant products to increase modern agriculture. The in vitro propagation method has appeared as a pre-eminent approach for the escalated production of healthy plants in relatively shorter durations, also circumventing seasonal effects. However, there are various kinds of factors that directly or indirectly affect the efficiency of in vitro regeneration like the concentration and combination of growth regulators, variety/genotype of the mother plant, explant type, age of seedlings and other nutritional factors, and elicitors. Nanotechnology as one of the latest and most advanced approaches in the material sciences, and can be considered to be very promising for the improvement of crop production. Nanomaterials have various kinds of properties because of their small size, such as an enhanced contact surface area, increased reactivity, stability, chemical composition, etc., which can be employed in plant sciences to alter the potential and performance of plants to improve tissue culture practices. Implementing nanomaterials with in vitro production procedures has been demonstrated to increase the shoot multiplication potential, stress adaptation and yield of plant-based products. However, nanotoxicity and biosafety issues are limitations, but there is evidence that implies the promotion and further exploration of nanoparticles in agriculture production. The incorporation of properly designed nanoparticles with tissue culture programs in a controlled manner can be assumed as a new pathway for sustainable agriculture development. The present review enlists different studies in which treatment with various nanoparticles influenced the growth and biochemical responses of seed germination, as well as the in vitro morphogenesis of many crop species. In addition, many studies suggest that nanoparticles can be useful as elicitors for elevating levels of important secondary metabolites in in vitro cultures. Recent advancements in this field also depict the suitability of nanoparticles as a promising carrier for gene transfer, which show better efficiency than traditional Agrobacterium-mediated delivery. This review comprehensively highlights different in vitro studies that will aid in identifying research gaps and provide future directions for unexplored areas of research in important crop species.

Exploring the genetic makeup and population structure among Capsicum accessions for crop improvement and breeding curriculum insights.

BACKGROUND: Capsicum or chilli is an important crop in India which exhibits immense structural and genetic variations reflecting their intra- and inter-specific relationships. The aim of this study was to establish relationships amongst 54 Capsicum accessions through analysis of genetic and population structure using ISSR markers. RESULTS: Out of 19, successful DNA amplifications were shown by 7 ISSR primers and a total of 80 bands were identified ranging between 8 and 14 with an average of 11.43 bands/primer. A significant degree of polymorphic information content (PIC), discriminating power (DP), resolving power (RP), effective multiplex ratio (EMR), and marker index (MI) were identified as 0.39, 0.70, 6.40, 5.88, and 2.30, respectively, using ISSR markers in chillies. The cross-transferability ranged from 8.0 to 72.15% with an average of 52.63% among chillies. Amongst genetic information, grand mean values were 0.264, 0.180, 0.376, 0.296, and 0.180, which correspond to Shannon's information index (I), expected heterozygosity (He), Nei's gene diversity, total diversity among species (Ht), diversity within species (Hs), respectively. Further, the coefficients of gene differentiation (Gst) and gene flow (Nm) were 0.393 and 0.773, representing higher genetic variation among the population which was confirmed by analysis of molecular variance (AMOVA). CONCLUSION: ISSR markers represented a potent system for the estimation of relationships or variation studies and generated information useful for planning crop management and improvement strategies in chilli breeding.

Variant biochemical responses: intrinsic and adaptive system for ecologically different rice varieties.

India has a diverse range of agro-ecological conditions which support the cultivation of different rice varieties differing in the adaptation which is so important for sustainable development of rice crop. Specific ecotypes of rice adapted to diverse conditions have divergence in their morphology, physiology, biochemistry, molecular function, agronomy, and stress response. In the present study, 12 different rice varieties viz., PB-1, PB-1509, Pusa-RH-10, CSR-30, HKR-47, PR-126, Govind, Sharbati, ADT-37, ADT-39, ADT-45, White Ponni, were selected for the study of intrinsic biochemical behaviour and these varieties belong to different Agro-ecological zones and basmati or non-basmati rice varieties. Amongst intrinsic biochemicals activity, the differential response of radical scavenging, superoxide dismutase (SOD), catalase (CAT) and guaiacol peroxidase (POX) activities, were observed in the selected rice varieties at 14 days old seedling stage, developed under controlled growth conditions. Comparatively, North India region rice varieties displayed an enhanced intrinsic biochemical response than south India region rice varieties. Similarly, basmati rice varieties showed increased biochemical response compared to non-basmati rice varieties. Thus, the differential biochemical responses (radical scavenging, SOD, CAT, and POX activities) observed creates a significant difference between rice varieties and provides valuable information about rice ecotype-biochemical interaction for sustainable adaptive value under different ecological conditions.

Surface Morphology and Physicochemical Characterization of Thermostable Moringa Gum: A Potential Pharmaceutical Excipient.

An efficient protocol for physico-chemical characterization of gum exudates collected from the drumstick tree (Moringa oleifera Lam.) has been reported in the present study. Extraction of gum metabolites was done using a series of water, alcohol, acid, and alkali solvent systems. The gum was sparingly soluble in water at room temperature and formed a colloidal solution. Solubility of the gum gradually increased in the solvent gradient (80% ethanol, deionized water, 0.05 M HCl, and 0.05 M NaOH) at 90 °C. Further, electron microscopy revealed that the acetyl group is essential in maintaining the structural integrity, and deacetylation of gum resulted in formation of a mesh of scattered and fibrous particles. Treatment of gum with deionized water resulted in development of a hydrocolloidal matrix with a pore size of 0.5 µm, which upon deacetylation was reduced up to 0.2 µm. The polymer was amorphous in nature and showed maximum thermal stability in ethanol. Gas chromatography-mass spectrometry of the gum polymer revealed that carbohydrate derivatives constituted its major part (>75%). Maximum carbohydrate concentration was obtained in the ethanol soluble fraction, along with fatty acids (10%) and secondary metabolites (9%). The results provided very first confirmation of the hydrocolloidal properties and thermostability of the gum exudates obtained from the drumstick tree, which can further be used to develop an eco-friendly and nontoxic bioligand.

Translation initiation codon (ATG) or SCoT markers-based polymorphism study within and across various Capsicum accessions: insight from their amplification, cross-transferability and genetic diversity.

Being an economical and nutritional crop, Capsicum appeases people's peppery taste and is found to bewidely distributed all over the world having vast diversity. In the present study, genetic polymorphism, cross transferability (CT) and genetic diversity were examined among the 54 different accessions of Capsicum species including 49 of Capsicum annuum, three of C. baccatum and two of C. frutescens, using a set of 36 start codon targeted (SCoT) primers. Of the total, 35 SCoT markers showed successful amplification profile among chilli germplasms and an average primer polymorphism was reported as 81.52% which ranged from 50% (SCoT-6) to 100% (SCoT-11). A total of 365 amplicons were obtained with an average of 10.43 bands per primer and the length of the bands ranged from 150 bp to 1.2 kb. Further, polymorphic information content value of SCoT markers ranged from 0.42 (for SCoT-25) to 0.86 (SCoT-27) with an average of 0.78. The average value of CT of SCoT markers was 44.08% ranged from 14.25% to 57.26% among different chilli accessions. A dendrogram was constructed and established genetic relationship among 54 capsicum species, with the help of translation initiation codon polymorphisms or SCoT primer amplification. This study suggests the effectiveness of SCoT marker system for characterizing and assessing genetic diversity of Capsicum germplasm, which can be used for evolutionary studies and to identify agronomically important traits.

Identification of suitable internal control genes for transcriptional studies in Eleusine coracana under different abiotic stress conditions.

Finger millet [Eleusine coracana (L.) Gaertn] is an excellent food and forage crop of arid and semiarid areas in Africa and Asia. It is well adapted to drought, heat, high salinity, poor soil fertility and low pH with an efficient C4 carbon fixation mechanism for high yield potential. To normalize the target gene expression data, the identification of suitable reference genes is essential. Ten candidate reference genes were selected and their expression stability was analyzed in various samples treated with different abiotic stress conditions. Five different statistical algorithms: geNorm, NormFinder, BestKeeper, ΔCt, and RefFinder were used to determine the stability of these genes. Our results revealed GAPDH, EEF1a, ACT and CYC as highly stable reference genes and PP2A and eIF4A as least stable reference genes across all the samples and suggesting that these genes could be used for accurate transcript normalization under abiotic stress. To the best of our knowledge, this is the first report on identification of suitable reference genes for accurate transcript normalization using qRT-PCR in finger millet under abiotic stress.

RAPD and ISSR marker assessment of genetic diversity in Citrullus colocynthis (L.) Schrad: a unique source of germplasm highly adapted to drought and high-temperature stress.

Citrullus colocynthis (L.) Schrad. (Cucurbitaceae) shows high levels of variation in fruit color, fruit stripe pattern, seed coat color, and size. Thirty-eight accessions of C. colocynthis plants from different parts of semi-arid Rajasthan were collected and genetic diversity was assessed using random-amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) markers. Out of 65 RAPD decamer primers, 50 primers produced 549 scorable bands of which 318 were polymorphic. Polymorphic banding patterns with the number of amplified fragments varied from 5 (OPA-08 and OPF-9) to 19 (OPT-20) in the molecular size range of 150-6000 bp. Percent polymorphism ranged from 22.2% (OPA-09) to 83.3% (OPE-12) with 55.14% polymorphism. Out of the 20 ISSR primers screened, 13 primers produced 166 amplification products, of which 99 were polymorphic. The number of bands amplified per primer varied between 9 (UBC-807, 802) and 16 (UBC-803, 812) with average band size between 250 and 4000 bp. Percent polymorphism ranged from 45.4% (UBC-815) to 73.3% (UBC-814) with 65.05% polymorphism. Dendrogram constructed on the basis of RAPD + ISSR polymorphism separated the accessions into four distinct clusters at 72% variation with Jaccard's similarity coefficient ranging from minimum 0.64 to 0.95. The matrices for RAPD and ISSR were also compared using Mantel's test and obtained correlation value (r = 0.7947). Discriminating power of RAPD and ISSR markers was assessed by calculating polymorphic information content, multiplex ratio, marker index, and resolving power. Approx. 50% RAPD and ISSR markers showed PIC value and heterozygosity (H) ≥ 0.50, indicating marker as informative. The primers that showed higher polymorphism had higher RP, MR, and MI values.

Nickel accumulation and its effect on growth, physiological and biochemical parameters in millets and oats.

With the boom in industrialization, there is an increase in the level of heavy metals in the soil which drastically affect the growth and development of plants. Nickel is an essential micronutrient for plant growth and development, but elevated level of Ni causes stunted growth, chlorosis, nutrient imbalance, and alterations in the defense mechanism of plants in terms of accumulation of osmolytes or change in enzyme activities like guiacol peroxidase (POD), catalase (CAT), and superoxide dismutase (SOD). Ni-induced toxic response was studied in seedlings of finger millet, pearl millet, and oats in terms of seedling growth, lipid peroxidation, total chlorophyll, proline content, and enzymatic activities. On the basis of germination and growth parameters of the seedling, finger millet was found to be the most tolerant. Nickel accumulation was markedly lower in the shoots as compared to the roots, which was the highest in finger millet and the lowest in shoots of oats. Plants treated with a high concentration of Ni showed significant reduction in chlorophyll and increase in proline content. Considerable difference in level of malondialdehyde (MDA) content and activity of antioxidative enzymes indicates generation of redox imbalance in plants due to Ni-induced stress. Elevated activities of POD and SOD were observed with high concentrations of Ni while CAT activity was found to be reduced. It was observed that finger millet has higher capability to maintain homeostasis by keeping the balance between accumulation and ROS scavenging system than pearl millet and oats. The data provide insight into the physiological and biochemical changes in plants adapted to survive in Ni-rich environment. This study will help in selecting the more suitable crop species to be grown on Ni-rich soils.

Effect of cadmium on physiological parameters of cereal and millet plants-A comparative study.

Metal load is an abiotic stress that becomes stronger by continual industrial production, wastage, and long-range transport of contaminants. It deteriorates the conditions of agricultural soil that leads to lower growth of cereals as well as decreasing nutritional value of harvested grains. Cadmium (Cd) entry by food chain also affects the health of population. The present study is focused on finding out the superior cereal variety under increasing Cd regime. The plants were grown in increasing Cd levels (0-1000 µM) in the medium and were investigated on 15th day of the exposure. Various parameters like antioxidative enzymes and osmoprotectant levels were studied in both roots and shoots. Cd accumulation in plant organs was determined by atomic absorption spectrophotometry (AAS). Analysis of stress tolerance mechanisms through reactive oxygen species (ROS) scavenging and better partitioning of Cd in roots indicated kodo millet to be more stress tolerant than wheat.

Assessment of Functional EST-SSR Markers (Sugarcane) in Cross-Species Transferability, Genetic Diversity among Poaceae Plants, and Bulk Segregation Analysis.

Expressed sequence tags (ESTs) are important resource for gene discovery, gene expression and its regulation, molecular marker development, and comparative genomics. We procured 10000 ESTs and analyzed 267 EST-SSRs markers through computational approach. The average density was one SSR/10.45 kb or 6.4% frequency, wherein trinucleotide repeats (66.74%) were the most abundant followed by di- (26.10%), tetra- (4.67%), penta- (1.5%), and hexanucleotide (1.2%) repeats. Functional annotations were done and after-effect newly developed 63 EST-SSRs were used for cross transferability, genetic diversity, and bulk segregation analysis (BSA). Out of 63 EST-SSRs, 42 markers were identified owing to their expansion genetics across 20 different plants which amplified 519 alleles at 180 loci with an average of 2.88 alleles/locus and the polymorphic information content (PIC) ranged from 0.51 to 0.93 with an average of 0.83. The cross transferability ranged from 25% for wheat to 97.22% for Schlerostachya, with an average of 55.86%, and genetic relationships were established based on diversification among them. Moreover, 10 EST-SSRs were recognized as important markers between bulks of pooled DNA of sugarcane cultivars through BSA. This study highlights the employability of the markers in transferability, genetic diversity in grass species, and distinguished sugarcane bulks.

In Vitro Shoot Cultures and Analysis of Steroidal Lactones in Withania coagulans (Stocks) Dunal.

Withania coagulans (Stocks) Dunal (Solanaceae), also known as 'Panir Bandh' is an important medicinal plant that is extensively used as a home remedy for several diseases in the Indian subcontinent. The plant possesses specific steroidal lactones known as withanolides which show high level of pharmaceutical activity against a broad spectrum of microorganisms. Natural propagation of the plant occurs through Seed but due to unisexual nature of the flowers; chances of Seed setting are very limited and the plant is on the verge of extinction because of overexploitation and reproductive failure. Plant tissue culture techniques offer opportunities for ex situ conservation and mass multiplication of endangered plant species through micropropagation and also enhancement of in vitro biosynthesis of bioactive compounds. In this chapter we present protocols for the mass multiplication of W. coagulans, assessment of clonal fidelity by RAPD, and estimation of bioactive compounds (withanolides) by thin layer chromatography (TLC) and reverse phase HPLC developed in our laboratory.

ExcellmiRDB for translational genomics: a curated online resource for extracellular microRNAs.

A large number of studies have suggested extracellular microRNAs (microRNAs in biofluids) as potential noninvasive biomarkers for pathophysiological conditions such as cancer. However, reported differentially expressed signatures of extracellular miRNAs in diseases are not uniformly consistent among studies. Here, we present "ExcellmiRDB", a curated online database that provides integrated information about miRNAs levels in biofluids in a user-friendly way. Although many miRNA databases, including disease-oriented databases, have been launched before, the ExcellmiRDB is so far the only one specialized for storing curated data on miRNA levels in biofluid samples. At present, ExcellmiRDB has 2773 disease-extracellular miRNAs and 1108 biofluid-extracellular miRNAs relationships curated from 108 articles selected from more than 600 surveyed PubMed abstracts. Information about 992 miRNAs, 82 diseases, 21 biofluids, 8 species, 63 normalization reference genes, 5 techniques, 14 GEO profiles accession numbers, 7 human ethnic groups, and 18 compared clinical biomarkers have been provided in the database. A user can query ExcellmiRDB by selecting a disease or a miRNA or a biofluid. Additionally, the database provides two online network graphs to visualize and interact with the content of the database. The first network shows disease-extracellular miRNAs relationships, along with expression patterns and number of articles for a relationship. The second network visualizes biofluid-extracellular miRNAs relationships showing miRNAs spectrum across different types of biofluids. In conclusion, ExcellmiRDB is a new innovative resource for both academic and industrial researchers in translational omics who are developing miRNA biomarkers for noninvasive diagnostic or prognostic technologies. ExcellmiRDB is publicly available on www.excellmirdb.brfjaisalmer.com/.

Identification and characterization of microsatellites in expressed sequence tags and their cross transferability in different plants.

Expressed sequence tags (EST) are potential source for the development of genic microsatellite markers, gene discovery, comparative genomics, and other genomic studies. In the present study, 7630 ESTs were examined from NCBI for SSR identification and characterization. A total of 263 SSRs were identified with an average density of one SSR/4.2 kb (3.4% frequency). Analysis revealed that trinucleotide repeats (47.52%) were most abundant followed by tetranucleotide (19.77%), dinucleotide (19.01%), pentanucleotide (9.12%), and hexanucleotide repeats (4.56%). Functional annotation was done through homology search and gene ontology, and 35 EST-SSRs were selected. Primer pairs were designed for evaluation of cross transferability and polymorphism among 11 plants belonging to five different families. Total 402 alleles were generated at 155 loci with an average of 2.6 alleles/locus and the polymorphic information content (PIC) ranged from 0.15 to 0.92 with an average of 0.75. The cross transferability ranged from 34.84% to 98.06% in different plants, with an average of 67.86%. Thus, the validation study of annotated 35 EST-SSR markers which correspond to particular metabolic activity revealed polymorphism and evolutionary nature in different families of Angiospermic plants.

Micropropagtion of Terminalia bellerica from nodal explants of mature tree and assessment of genetic fidelity using ISSR and RAPD markers.

The present study reports an efficient in vitro micropropagation protocol for a medicinally important tree, Terminalia bellerica Roxb. from nodal segments of a 30 years old tree. Nodal segments taken from the mature tree in March-April and cultured on half strength MS medium gave the best shoot bud proliferation response. Combinations of serial transfer technique (ST) and incorporation of antioxidants (AO) [polyvinylpyrrolidone, PVP (50 mg l(-1)) + ascorbic acid (100 mg l(-1)) + citric acid (10 mg l(-1))] in the culture medium aided to minimize browning and improve explant survival during shoot bud induction. Highest multiplication of shoots was achieved on medium supplemented with 6-benzyladenine (BA, 8.8 µM) and α-naphthalene acetic acid (NAA, 2.6 µM) in addition to antioxidants. Shoot elongation was obtained on MS medium containing BA (4.4 µM) + phloroglucinol (PG, 3.9 µM). Elongated shoots were transferred to half strength MS medium containing indole-3-butyric acid (IBA, 2.5 µM) for root development. The acclimatization of plantlets was carried out under greenhouse conditions. The genetic fidelity of the regenerated plants was checked using inter simple sequence repeats (ISSR) and randomly amplified polymorphic DNA (RAPD) analysis. Comparison of the bands among the regenerants and mother plant confirmed true-to-type clonal plants.

Chloroplast ultra structure, photosynthesis and enzyme activities in regenerated plants of Stevia rebaudiana (Bert.) Bertoni as influenced by copper sulphate in the medium.

Stevia rebaudiana (Bert.) Bertoni is an important medicinal plant used as noncaloric commercial sweetener. Plants regenerated with higher levels of copper sulphate in the medium exhibited enhanced activity of peroxidase and polyphenoloxidase (PPO) enzymes. Transmission electron microscopy (TEM) revealed increase in size and number of electron dense inclusions in the chloroplasts of plants regenerated at optimised level of copper sulphate (0.5 microM) in the medium. There was decrease in chlorogenic acid (CGA) content. Chl-a-fluorescence transient pattern (OJIP) showed that the photosynthesis process was more efficient at 0.5 microM CuSO4 in the medium.

Antimycobacterial activity of Citrullus colocynthis (L.) Schrad. against drug sensitive and drug resistant Mycobacterium tuberculosis and MOTT clinical isolates.

ETHNOPHARMACOLOGICAL RELEVANCE: Citrullus colocynthis (Cucurbitaceae), a folk herbal medicine and traditionally used natural remedy for tuberculosis in India has been studied to validate its antitubercular activity against drug sensitive and drug resistant (including multidrug resistant) Mycobacterium tuberculosis and Mycobacterium other than tuberculosis (MOTT) bacilli. MATERIALS AND METHODS: Inhibitory and bactericidal activities of crude extracts, fractions and compounds of Citrullus colocynthis plant, consisting of aerial parts and ripe deseeded fruits were performed against the drug sensitive standard strain of Mycobacterium tuberculosis H37Rv (ATCC 27294), 16 drug resistant strains of Mycobacterium tuberculosis and two MOTT strains, using radiometric BACTEC 460TB system. RESULTS: Methanolic extract of ripe deseeded fruit of Citrullus colocynthis has shown good activity (MIC ≤ 62.5 µg/ml), whereas among the bioactive fractions, FC IX demonstrated the best activity (MIC 31.2 µg/ml) against Mycobacterium tuberculosis H37Rv. Bioactive FC III, IX and X also inhibited 16 clinical isolates of Mycobacterium tuberculosis consisting of seven non-multidrug resistants, eight multidrug resistants, one extensively drug resistant and two of MOTTs with MICs in the range of 50-125, 31.2-125 and 62.5-125 µg/ml, respectively. Ursolic acid and cucurbitacin E 2-0-ß-d-glucopyranoside were identified as the main biomarkers active against Mycobacterium tuberculosis H37Rv (MICs 50 and 25 µg/ml respectively), as well as against the 18 clinical isolates. FC III and FC IX showed better inhibition of drug resistant and MOTT clinical isolates. Minimal bactericidal concentrations of extracts, fractions and compound C-2 were ≥ two-fold MIC values. CONCLUSIONS: The study provides a scientific rationale for the traditional use of Citrullus colocynthis fruit in the treatment of tuberculosis. In addition, the study elucidates a broad spectrum antimycobacterial action of Citrullus colocynthis fruit, which can contribute to the development of improved preparation of an antitubercular natural drug for the treatment of drug resistant tuberculosis and MOTT infection as well.

Micropropagation of Pithecellobium dulce (Roxb.) Benth-a multipurpose leguminous tree and assessment of genetic fidelity of micropropagated plants using molecular markers.

An efficient and reproducible protocol has been developed for in vitro propagation of Pithecellobium dulce (Roxb.) Benth (a multipurpose leguminous tree) from field grown nodal segments (axillary bud). Shoot bud induction occurred from nodal explants of 15-years-old tree on Murashige and Skoog (MS) basal medium supplemented with 4.4 µM 6-benzyladenine (BA) and multiplication was achieved on MS medium supplemented with 4.4 µM BA + 0.73 µM phenylacetic acid (PAA) i.e. up to 7 shoot buds in the period of 5-6 weeks. Addition of adenine sulphate (AdS) to this medium further enhanced the number of shoot buds up to 10. Proliferating shoot cultures were established by repeatedly subculturing primary culture on fresh medium (MS + 4.4 µM BA + 0.73 µM PAA) after every 25 days. In vitro rooting was achieved on MS medium supplemented with 2.46 µM Indole-3-butyric acid (IBA) + 41.63 µM activated charcoal (AC). The micropropagated shoots with well developed roots were acclimatized in green house in pots containing sand, soil and manure (1:1:1). Genetic stability of micropropagated clones was evaluated using Random amplified polymorphic DNA (RAPD) and Inter simple sequence repeat (ISSR) markers. The amplification products were monomorphic in micropropagated plants and similar to those of mother plant. No polymorphism was detected revealing the genetic uniformity of micropropagated plants. This is the first report of an efficient protocol for regeneration of P. dulce through organogenesis, which can be used for further genetic transformation and pharmaceutical purposes.

Novel microbial route to synthesize silver nanoparticles using spore crystal mixture of Bacillus thuringiensis.

Metallic nanoparticles are traditionally synthesized by wet chemical techniques, where the chemicals used are often toxic and flammable. In the present study, the spore crystal mixture of Bacillus thuringiensis was used for the synthesis of silver nanoparticles. Nanoparticles were characterized using UV-Vis absorption spectroscopy, XRD and TEM. X-ray diffraction and TEM analysis showed the average particle size of 15 nm and mixed (cubic and hexagonal) structure. This is for the first time that any bacterial spore crystal mixture was used for the synthesis of nanoparticles. Further, these biologically synthesized nanoparticles were found to be highly toxic against different multi drug resistant human pathogenic bacteria.