In vitro propagation, genetic and secondary metabolite analysis of Aconitum violaceum Jacq.: a threatened medicinal herb

Aconitum violaceum Jacq. is an important medicinal species used for various health ailments including renal pain, rheumatism and high fever. In the present report, a reproducible in vitro regeneration system for Aconitum violaceum Jacq. has developed from the nodal segment of the plant. Induction of shoot buds was achieved on basal Murashige and Skoog (MS) medium. The shoots were elongated on MS medium supplemented with 0.5 μM 6-benzylaminopurine (BAP) and 0.1 μM α-napthaleneacetic acid (NAA) and subsequently transferred to rooting medium. In vitro grown microshoots of A. violaceum were encapsulated in the alginate beads. The success rate of their re-growth was found to be approximately 85.43 %. Of the encapsulated microshoots, 39.86 % exhibited formation of multiple shoots following re-growth on plant growth regulator free MS medium. Healthy root formation was observed in all microshoots following 2 weeks of transfer on half-strength MS medium containing 0.1 μM indole-3-acetic acid (IAA) and 1.0 μM α-naphthalene acetic acid (NAA). These plants were subsequently transferred to pots containing a mixture of soil, sand and compost (1:1:1 v/v), and same were then shifted in the greenhouse with 87 % survival rate. The molecular analysis was carried out using 35 random amplified polymorphic DNAs (RAPD) primers and 25 inter simple sequence repeats (ISSR) primers. Cluster analysis of the RAPD and ISSR profile revealed an average similarity coefficient of 0.966 and 0.974, respectively, confirming genetic stability of tissue culture-raised (TR) plants and synthetic seed-derived plants (SR). The phytochemical analysis of tissue culture-raised and synthetic seeds-derived plants showed higher aconitine content than control plant. The propagation protocol developed in this study provides a basis for germplasm conservation and harnessing the medicinally active compounds of A. violaceum.     

Spatial distribution and regeneration of Quercus semecarpifolia and Quercus floribunda in a subalpine forest of western Himalaya, India

Studies were conducted on population status and regeneration of Quercus semecarpifolia and Quercus floribunda in a subalpine forest of western Himalaya. Saplings of Q. semecarpifolia belonging to the 51-100 cm size class and those of Q. floribunda belonging to the 101-150 cm size class were well represented in studied subalpine forests. Comparable seedling emergence and establishment of both species, either in the habitat dominated by same or different species seems to be an adaptational strategy of these species in subalpine forests. Seedling to tree ratio for Q. semecarpifolia was higher in the stand dominated by Q. floribunda, while comparable pattern was observed for Q. floribunda in the stand dominated by Q. semecarpifolia. Establishment of higher percent of seedlings of one species in the habitats dominated by another species of Quercus appears to indicate an oligarchic nature of oaks in subalpine forests. This study describes regeneration strategies, and spatial distribution of these species in a subalpine forest of Uttarakhand.     

Identification of flavonoids in the stems and leaves of Scutellaria baicalensis Georgi

Scutellaria baicalensis Georgi (S. baicalensis), a perennial herb of the Labiatae family, is a well-known traditional Chinese medicine. In the present study, a comprehensive qualitative analysis of flavonoids in the stems and leaves of S. baicalensis was performed. Under the optimized experimental conditions, 21 flavonoids were clearly detected. 17 of them were successfully identified based on the on-line UV and MS(n) data and were sequentially confirmed by the literature search. The rest 4 flavonones, which were not on-line identified, were successfully isolated and were identified by 1D and 2D NMR. One of them, 5,6,7,3',4'-pentahydroxy flavanone-7-O-glucuronide (2) is a new compound.     

Changes in Bacterial Community Structure of Agricultural Land Due to Long-Term Organic and Chemical Amendments

Community level physiological profiling and pyrosequencing-based analysis of the V1-V2 16S rRNA gene region were used to characterize and compare microbial community structure, diversity, and bacterial phylogeny from soils of chemically cultivated land (CCL), organically cultivated land (OCL), and fallow grass land (FGL) for 16 years and were under three different land use types. The entire dataset comprised of 16,608 good-quality sequences (CCL, 6,379; OCL, 4,835; FGL, 5,394); among them 12,606 sequences could be classified in 15 known phylum. The most abundant phylum were Proteobacteria (29.8%), Acidobacteria (22.6%), Actinobacteria (11.1%), and Bacteroidetes (4.7%), while 24.3% of the sequences were from bacterial domain but could not be further classified to any known phylum. Proteobacteria, Bacteroidetes, and Gemmatimonadetes were found to be significantly abundant in OCL soil. On the contrary, Actinobacteria and Acidobacteria were significantly abundant in CCL and FGL, respectively. Our findings supported the view that organic compost amendment (OCL) activates diverse group of microorganisms as compared with conventionally used synthetic chemical fertilizers. Functional diversity and evenness based on carbon source utilization pattern was significantly higher in OCL as compared to CCL and FGL, suggesting an improvement in soil quality. This abundance of microbes possibly leads to the enhanced level of soil organic carbon, soil organic nitrogen, and microbial biomass in OCL and FGL soils as collated with CCL. This work increases our current understanding on the effect of long-term organic and chemical amendment applications on abundance, diversity, and composition of bacterial community inhabiting the soil for the prospects of agricultural yield and quantity of soil.     

Evaluation of wild <Emphasis Type="Italic">Arachis</Emphasis> species for cultivation under semiarid tropics as a fodder crop

Wild Arachis genotypes were analysed for chlorophyll a fluorescence, carbon isotope discrimination (ΔC), specific leaf area (SLA), and SPAD readings. Associations between different traits, i.e., SLA and SPAD readings (r =–0.76), SLA and ΔC (r = 0.42), and ΔC and SPAD readings (r = 0.30) were established. The ratio of maximal quantum yield of PSII photochemistry (F_v/F_m) showed a wider variability under water deficit (WD) than that after irrigation (IR). Genotypes were grouped according to the F_v/F_m ratio as: efficient, values between 0.80 and 0.85; moderately efficient, the values from 0.79 to 0.75; inefficient, the values < 0.74. Selected Selected genotypes were evaluated also for their green fodder yield: the efficient genotypes ranged between 3.0 and 3.8, the moderately efficient were 2.6 and 2.7, the inefficient genotypes were of 2.3 and 2.5 t ha^?1 per year in 2008 and 2009, respectively. Leaf water-relation traits studied in WD and IR showed that the efficient genotypes were superior in maintenance of leaf water-relation traits, especially, under WD. Potential genotypes identified in this study may enhance biomass productivity in the semiarid tropic regions.     

Biocontrol Efficacy of Bacillus subtilis Strains Isolated from Cow Dung Against Postharvest Yam (Dioscorea rotundata L.) Pathogens

The biocontrol potential of Bacillus subtilis isolated from cow dung microflora was investigated in vitro and in vivo against two postharvest yam pathogenic fungi, Fusarium oxysporum and Botryodiplodia theobromae. B. subtilis strains inhibited the growth of F. oxysporum and B. theobromae in vitro in liquid medium in the range of 49.3–56.6% and in solid medium in the range of 31.0–36.0%, in comparison to the corresponding growth of fungi without bacterial inoculation. The interaction between B. subtilis CM1 and F. oxysporum was also studied by scanning electron microscopy. Chitinase production was demonstrated in vitro when B. subtilis was grown in the presence of colloidal chitin as the sole carbon source in a liquid medium. In vivo study showed that B. subtilis strains inhibited the growth of fungi (F. oxysporum and B. thobromae) up to 83% in wound cavities of yam tubers.     

Crystal structure of a designed, thermostable, heterotrimeric coiled coil

Electrostatic interactions are often critical for determining the specificity of protein-protein complexes. To study the role of electrostatic interactions for assembly of helical bundles, we previously designed a thermostable, heterotrimeric coiled coil, ABC, in which charged residues were employed to drive preferential association of three distinct, 34-residue helices. To investigate the basis for heterotrimer specificity, we have used multiwavelength anomalous diffraction (MAD) analysis to determine the 1.8 A resolution crystal structure of ABC. The structure shows that ABC forms a heterotrimeric coiled coil with the intended arrangement of parallel chains. Over half of the ion pairs engineered to restrict helix associations were apparent in the experimental electron density map. As seen in other trimeric coiled coils, ABC displays acute knobs-into-holes packing and a buried anion coordinated by core polar amino acids. These interactions validate the design strategy and illustrate how packing and polar contacts determine structural uniqueness.