Phenotypic Switching in Biofilm-Forming Marine Bacterium Paenibacillus lautus NE3B01

Biofilm-forming marine bacterium Paenibacillus lautus NE3B01 was isolated from a mangrove ecosystem, Odisha, India. This isolate formed a swarming type of colony pattern on the solid culture medium with 0.5–2 % agar. Phase contrast microscopy study of a growing colony of P. lautus on solid media and swarming pattern revealed the existence of two phenotypically distinct cells (i.e. cocci and rods) across the colonies. However, in actively growing planktonic culture, only rod-shaped cells were observed. Biofilm growth studies (crystal violet assay) with the isolate showed significant biofilm formation by 6 h, and the detachment phase was observed after 18 h. Biofilm parameters (such as total biomass, roughness coefficient, biofilm thickness, etc.) of 24-h-old P. lautus biofilm were studied by confocal scanning laser microscopy (CSLM). The CSLM study showed that P. lautus formed a biofilm with an average thickness of 14.8 ± 2.6 μm, a high roughness coefficient (0.379 ± 0.103) and surface to bio-volume ratio (4.59 ± 1.12 μm²/μm³), indicating a highly uneven topography of the biofilm. This also indicates that the 24-h-old biofilm is in dispersal phase. Scanning electron microphotographs of P. lautus also supported the existence of two distinct phenotypes of P. lautus. The current findings suggest that P. lautus has two vegetative phenotypes and to decongest the overcrowded biofilm the bacterium can switch over to motile rods from nonmotile cocci and vice versa.     

Performance Estimation of Hybrid Plasmonic Waveguide in Presence of Stress

Plasmonics - In this paper, a detailed numerical investigation has been carried out to find the effect of stress on the optical performances of hybrid plasmonic waveguides (HPWs) operating at 1550...     

Influence of Long Term Irrigation with Pulp and Paper Mill Effluent on the Bacterial Community Structure and Catabolic Function in Soil

Microbial communities play a vital role in maintaining soil health. A multiphasic approach to assess the effect of pulp and paper mill effluent on both the structure and function of microbial soil communities is taken. Bacterial communities from agricultural soils irrigated with pulp and paper mill effluent were compared to communities form soils irrigated with well water. Samples were taken from fields in the state of Uttarakhand, India, where pulp and paper mill effluent has been used for irrigation for over 25 years. Comparisons of bacterial community structure were conducted using sequencing of the 16S rRNA gene from both isolates and clone libraries attained from the soil. Community-level physiological profiling was used to characterize the functional diversity and catabolic profile of the bacterial communities. The multiphasic approach using both physiological and molecular techniques proved to be a powerful tool in evaluating the soil bacterial community population and population differences therein. A significant and consistent difference in the population structure and function was found for the bacterial communities from soil irrigated with effluent in comparison to fields irrigated with well water. The diversity index parameters indicated that the microbial community in pulp and paper mill effluent irrigated fields were more diverse in both structure and function. This suggests that the pulp and paper mill effluent is not having a negative effect on the soil microbial community, but in fact may have a positive influence. In terms of soil health, this finding supports the continued use of pulp and paper mill effluent for irrigation. This is however only one aspect of soil health which was evaluated. Further studies on soil resistance and robustness could be undertaken to holistically evaluate soil health in this situation.     

Isolation and HPLC assisted quantification of two iridoid glycoside compounds and molecular DNA fingerprinting in critically endangered medicinal Picrorhiza kurroa Royle ex Benth: implications for conservation

Picrorhiza kurroa is a medicinally important, high altitude perennial herb, endemic to the Himalayas. It possesses strong hepato-protective bioactivity that is contributed by two iridoid picroside compounds viz Picroside-I (P-I) and Picroside-II (P-II). Commercially, many P. kurroa based hepato-stimulatory Ayurvedic drug brands that use different proportions of P-I and P-II are available in the market. To identify genetically heterozygous and high yielding genotypes for multiplication, sustained use and conservation, it is essential to assess genetic and phytochemical diversity and understand the population structure of P. kurroa. In the present study, isolation and HPLC based quantification of picrosides P-I and P-II and molecular DNA fingerprinting using RAPD, AFLP and ISSR markers have been undertaken in 124 and 91 genotypes, respectively. The analyzed samples were collected from 10 natural P. kurroa Himalayan populations spread across four states (Jammu & Kashmir, Sikkim, Uttarakhand and Himachal Pradesh) of India. Genotypes used in this study covered around 1000 km geographical area of the total Indian Himalayan habitat range of P. kurroa. Significant quantitative variation ranging from 0.01 per cent to 4.15% for P-I, and from 0.01% to 3.18% in P-II picroside was observed in the analyzed samples. Three molecular DNA markers, RAPD (22 primers), ISSR (15 primers) and AFLP (07 primer combinations) also revealed a high level of genetic variation. The percentage polymorphism and effective number of alleles for RAPD, ISSR and AFLP analysis varied from 83.5%, 80.6% and 72.1%; 1.5722, 1.5787 and 1.5665, respectively. Further, the rate of gene flow (Nm) between populations was moderate for RAPD (0.8434), and AFLP (0.9882) and comparatively higher for ISSR (1.6093). Fst values were observed to be 0.56, 0.33, and 0.51 for RAPD, ISSR and AFLP markers, respectively. These values suggest that most of the observed genetic variation resided within populations. Neighbour joining (NJ), principal coordinate analysis (PCoA) and Bayesian based STRUCTURE grouped all the analyzed accessions into largely region-wise clusters and showed some inter-mixing between the populations, indicating the existence of distinct gene pools with limited gene flow/exchange. The present study has revealed a high level of genetic diversity in the analyzed populations. The analysis has resulted in identification of genetically diverse and high picrosides containing P. kurroa genotypes from Sainj, Dayara, Tungnath, Furkia, Parsuthach, Arampatri, Manvarsar, Kedarnath, Thangu and Temza in the Indian Himalayan region. The inferences generated in this study can be used to devise future resource management and conservation strategies in P. kurroa.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12298-021-00972-w.     

Synthesis,molecular docking,ADME study,and antimicrobial potency of piperazine based cinnamic acid bearing coumarin moieties as a DNA gyrase inhibitor

A series of novel piperazine based cinnamic acid bearing coumarin derivatives were designed and synthesized by piperazine based cinnamic acids esterification with 4-hydroxycoumarin and characterized by various spectral techniques like infrared, ¹H nuclear magnetic resonance (NMR), ¹³C NMR, and mass. The novel bioactive compounds (7a-7m) screen their potential against different bacterial and fungal strains. Compound 7g (minimum inhibitory concentration [MIC] = 12.5 µg/ml) exhibited potent antibacterial activity against Escherichia coli strain. Compounds 7d, 7f, 7g, 7k, 7l , and 7m showed potent antibacterial activity against all bacterial strains. Compounds 7a, 7g, 7h, 7k, 7l , and 7m exhibited potent antifungal activity against all fungal strains. Furthermore, a molecular docking study revealed that compounds 7d, 7f, 7g , and 7k could bind to the active site of E. coli DNA gyrase subunit B protein and form hydrogen bonding with crucial amino acid residues Arg136 in the active sites. Comprehensively, our study recommends that 7d, 7f, 7g , and 7k could be a promising lead for developing more efficient antimicrobial drug candidates and DNA gyrase inhibitors.     

Seasonal Adreno-Cortical Cycle of a Nocturnal Bird, Indian Spotted Owlet Athene brama: Biochemical and Morphological Observations

It is well reported that the environmental factors along with different endocrine stimulus play a crucial role in maintenance of adrenocortical activity in birds. This study is first to report a detailed seasonal activity cycle of adrenal cortex, particu-larly its secretory physiology in a tropical nocturnal bird, Indian spotted owlet Athene brama . The maximum cortical activity having highest glandular mass, glandular free cholesterol, esterified cholesterol profiles, and peak level of corticosterone in plasma coincided with the long day length, highest temperature and increasing amplitude of relative humidity and rainfall of the early summer month, May. Cortical activity declined to minimum level in August when the ecofactors also declined parallely and hence, the birds entered into partial hibernation. The cortical activity progressed slowly throughout the winter (September-March) to reach maximum level in May. Further, the electron microscopic observations of cortical cell morphology strongly supported the above seasonal activity status of the gland revealing a comparatively large number of mitochondria during May than August, along with lipid filled vacuoles during May but not in August. Besides, assessment of gonadal and pineal hormones in relation with seasonal activity of adrenal cortex presented a parallel relationship with gonad while completely inverse relationship with pineal. Therefore, the study concludes that the seasonal adrenocortical activity of this tropical nocturnal bird might be regulated by multiple factors, particularly by the environmental temperature, humidity/rainfall and photoperiod along with the internal factors at least by gonadal and pineal hormones.     

Exocytosis by vesicle crumpling maintains apical membrane homeostasis during exocrine secretion

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Honeybee nutrition and pollen substitutes: A review

Like other invertebrates, honey bees too are poikilothermic animals; they cannot regulate their body temperature and they have to undergo a period of inactivation when atmospheric temperature is un-tolerable. During this period, their nutritional requirements and metabolic activities are minimized due to highly restricted foraging activities. The egg-laying by queen and rearing of unsealed and sealed brood are decreased, however their extent is governed by the quantum of stored food available. The problems of deleterious influence of adverse weather conditions and non-availability of bee flora all round the year, in a particular locality, have been realized by the researchers/beekeepers and migration concept has been developed to solve this problem. But again, migration itself is not an easy task. The provision of artificial feeding as an alternate of migration. Scientists all over the world have formulated different artificial food recepies for bees on the basis of nutrient composition of honey and pollen, acceptability, palatability, digestibility and affordability of ingredients. This may help to maintain all colony parameters enough to derive maximum advantage of forthcoming floral rich season. However, a standard balanced diet for commercial beekeeping that is accepted worldwide is still awaited.