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Endophytic microorganisms which are ubiquitously present in plants may colonize intracellularly or intercellularly without causing any diseases. By living within the unique chemical environment of a host plant, they produce a vast array of compounds with a wide range of biological activities. Because of this, natural products of endophytic origin have been exploited for antimicrobial, antiviral, anticancer, and antioxidant properties. Also, they can be considered to function as an efficient microbial barrier to protect plants from various pathogens. In the present study, endophytic bacterium BmB 9 with antifungal and antibacterial activity isolated from the stem tissue of Bacopa monnieri was studied for the molecular and chemical basis of its activity. PCR-based genome mining for various biosynthetic gene clusters proved the presence of surfactin, iturin, and type I polyketide synthase (PKS) genes in the isolate. The LC–MS/MS based analysis of the extract further confirmed the production of surfactin derivatives (M + H⁺—1008.6602, 1022.6755), iturin (M + H⁺—1043.5697), and fengycin (M + H⁺—1491.8195, 1477.8055) by the selected bacterial isolate. The 16S rDNA sequence similarity based analysis identified the isolate BmB 9 as Bacillus sp. with 100 % identity to Bacillus sp. LCF1 (KP257289).

Pigment from the endophyte Burkholderia sp. WYAT7 isolated from the medicinal plant Artemisia nilagirica (Clarke) Pamp. was extracted. The antibacterial efficacy of the crude pigment Y was assessed as a source of antibiotic against both Gram-positive and Gram-negative bacterial pathogens. The pigment Y exhibited a significant level of antibacterial activity against the tested pathogens Salmonella typhi (MTCC 733), Staphylococcus aureus (MTCC 1430), Pseudomonas aeruginosa (MTCC 2453), Klebsiella pneumoniae (MTCC 432), Escherichia coli (MTCC 1610), Salmonella paratyphi (3220), Bacillus subtilis (441) and Acinetobacter baumannii (12,889). The minimum inhibitory concentration of crude pigment extract Y for most of the bacterial pathogens tested was below or equal to 0.25 µg/mL and the minimum bactericidal concentration was below or equal to 0.5 µg/mL. In the cytotoxicity evaluation, crude pigment Y exhibited less toxicity toward normal cells lines (L929). Crude pigment extract Y also showed powerful anticancer activity toward melanoma cancer cells (A375). The IC50 value obtained was 68.08 µg/mL. Acridine orange (AO) and ethidium bromide (EB) double staining of cells treated with the pigment helped in the morphological assessment of nuclear condensation, apoptotic bodies and live cells. The DNA fragmentation analysis and caspase-9 quantification in the pigment-treated A375 cells determined the apoptosis activity mediated by the crude pigment extract Y. The compounds in the crude pigment extract Y was identified by HR-LCMS analysis. Further studies on the active compounds can lead to a rise in new drugs for cancer treatment and also against rising antibacterial resistant pathogens.

Piper nigrum is an interesting plant to study the endophytic microbial factors affecting plant growth because of its unique features. Endophytic bacterial isolation from the plant resulted in the isolation of twelve bacterial isolates which were screened for various plant growth promoting properties like phosphate solubilization, ACC deaminase production, siderophore production etc. Interestingly, seven isolates were found to have IAA biosynthetic potential. Bacterial isolates with multiple plant growth promoting properties were studied for their growth promoting effect on Vigna radiata seedlings. This resulted in the identification of Klebsiella sp. (PnB 10) and Enterobacter sp. (PnB 11) as the isolates with excellent growth promoting properties. The results confirm promising applications of the endophytic bacterial isolates obtained in the study and also their possible growth promoting effect in P. nigrum .

Metal nanoparticle synthesis is an interesting area in nanotechnology due to their remarkable optical, magnetic, electrical, catalytic and biomedical properties, but there needs to develop clean, non-toxic and environmental friendly methods for the synthesis and assembly of nanoparticles. Biological agents in the form of microbes have emerged up as efficient candidates for nanoparticle synthesis due to their extreme versatility to synthesize diverse nanoparticles with varying size and shape. In the present study, an eco favorable method for the biosynthesis of silver nanoparticles using marine bacterial isolate has been attempted. Very interestingly, molecular identification proved it as a strain of Ochrobactrum anhtropi. In addition, the isolate was found to have the potential to form silver nanoparticles intracellularly at room temperature within 24 h. The biosynthesized silver nanoparticles were characterized by UV-Vis spectroscopy, transmission electron microscope (TEM) and scanning electron microscope (SEM). The UV-visible spectrum of the aqueous medium containing silver nanoparticles showed a peak at 450 nm corresponding to the plasmon absorbance of silver nanoparticles. The SEM and TEM micrographs revealed that the synthesized silver nanoparticles were spherical in shape with a size range from 38 nm - 85 nm. The silver nanoparticles synthesized by the isolate were also used to explore its antibacterial potential against pathogens like Salmonella Typhi, Salmonella Paratyphi, Vibrio cholerae and Staphylococcus aureus.

Bacterial fish pathogens are pervasive in aquaculture. Control of bacterial fish pathogen is a difficult task among aquaculture practitioners. A large number of antibiotics are used for the control of prevalent bacterial pathogens in aquaculture. This may lead to drug resistance among pathogens and further treatment will be ineffective. Here, we can use probiotic bacteria as a biocontrol agent in fish disease and it is a novel field. In this study, antimicrobial potential of the bacterium Bacillus coagulans (MTCC-9872) has been evaluated through in vitro antagonistic activity of cellular preparations/components against potent pathogens. The cellular preparations/components such as Ethyl acetate extract, whole-cell product, heat-killed whole-cell product, and filtered broth were exhibited bactericidal activity against the tested pathogens. Bactericidal activity varied among different cellular preparation/components. The tested bacterium effectively produced biofilm as significant as tested positive control in a microtitre plate and effectively adhered on to the glass slide. In addition, the bacterium was capable of producing extracellular enzymes necessary for the digestion of food materials and was capable to grow in fish mucus from Oreochromis niloticus. The bacterium tolerated bile juice secreted by the host. Moreover, intraperitoneal injection of the bacterium did not induce any pathological signs, symptoms or mortalities in Oreochromis niloticus and revealed the safety of this bacterium in the fish.

The plant Rotula aquatica Lour. was traditionally well known due to its large number of pharmacological action and medicinal uses. The plant is a necessary component of many Ayurvedic drug preparations since historical times. It is widely used as a crucial ancient drug for kidney and bladder stones. The main objective of the study was to evaluate the acute toxicity and anti inflammatory efficacy of methanolic extract of R.aquatica Lour. in in vivo models. The qualitative phytochemical analysis and invitro antioxidant activity of the roots of methanolic extract of R.aquatica Lour. (MERA) was evaluated. The acute toxicity effect of MERA was evaluated with two different doses (550, 2000 mg/kg body weight), were administrated orally to Wistar rats. The rats were observed for sign and symptoms of toxicity and mortality for 14 days. The parameters measured including relative organ weight, blood, biochemical and histopathological parameters of hepatic and renal toxicity. The anti-inflammatory effect of MERA was also evaluated in carrageenan and dextran-induced paw edema models. The phytochemical evaluation of MERA shows the presence of secondary metabolites like alkaloids, flavonoids, phenolics and tannins, phytosterols, reducing sugars, proteins and terpenoids. The results of in-vitro antioxidant evaluation of MERA reveal its capability to scavenging free radical at a lower concentration. The MERA did not show any visible signs of toxicity up to the dose of 2000 mg/kg body weight. The results obtained from our carrageenan and dextran-induced paw edema model study also proved the anti-inflammatory effect of MERA in rat model. The result shows the potential of MERA as an anti-inflammatory drug to reduce the signs of inflammation devoid of any toxic effect. [Display omitted] •Safety assessment of Rotula aquatica Lour. in in-vivo model.•Anti inflammatory effect of methanolic extract of R.aquatica Lour. roots was studied.•Biochemical and Histopathological changes were evaluated.•Methanolic extract of R.aquatica Lour. roots was safe upto 2000 mg/kg b.wt.•The methanolic extract posses potent anti inflammatory effect in 200 mg/kg b.wt.

Changes in water quality and environmental factors have been reported to play key roles on the health and disease susceptibility of the ornamental fish Xiphophorus hellerii (sword tail). This can further be decided by the natural distribution of pathogens with enhanced virulence properties in the aquatic system. As Aeromonas spp. are the major fish pathogens, a detailed analysis on its association with the disease of X.hellerii was conducted in the study. Here, bacterial isolation has been carried out from the surface, gill and intestine of diseased fish, and also from water samples. The twelve bacterial isolates obtained were identified biochemically and also by 16S rDNA sequence analysis as Aeromonas spp.. Among the various virulence properties screened by in vitro and PCR-based methods, most of the Aeromonas spp. were found to be positive for multiple virulence properties. Further disease challenge using the highly virulent Aeromonas veronii XhG1.2 in X. hellerii showed remarkable histopathological changes of the gill, liver, and intestine in the treated fish. This confirmed the hyper -pathogenic potential of XhG1.2 as the disease occurred within a short period of 24 h. The identification of broad range of virulence factors among the fish pathogenic bacterial isolates of aquatic environment indicates the need for periodic screening to predict the threat to aquatic life especially fish.

Acacia catechu L., (Fabaceae) named as “catechu” is a plant, the decoction of heartwood of which is daily consumed as thirst quencher by a good percentage of the population in South India. The plant is mainly distributed in India and other Asian countries. It has been used in Indian traditional medicine for the treatment of asthma, bronchitis, colic, diarrhea, boils, skin afflictions, sores and stomatitis. The present investigation was aimed to study the immunomodulatory effects of different fractions of ethanol extract of A. catechu heartwood and HPLC analysis of the active fraction. Three fractions namely, butanol, chloroform and ethyl acetate were prepared from ethanol extract of A. catechu heartwood. Each of these fractions was assessed for its immunomodulatory activity. In vivo immunomodulatory activity was analyzed by sheep red blood cells (SRBC) specific hemagglutinating antibody titer, plaque-forming cell assay and delayed type hypersensitivity (DTH) reaction in Swiss albino mice. In vitro immunomodulating potential of the fractions was studied using murine peritoneal macrophages and splenocytes. Non-specific immune functions such as phagocytosis (nitroblue tetrazolium reduction assay and cellular lysosomal enzyme assay), nitric oxide (NO) production and cytokine release (TNF-α and IL-10) were studied in macrophages. In addition, splenocyte proliferation was also studied. In the in vivo experiments, butanol and chloroform fractions showed an increase in antibody titer dose-dependently. At higher dose (400 mg/kg b. w.) treatment the butanol fraction produced an enhancement in the number of plaque-forming cells (antibody producing cells) in the spleen. SRBC induced DTH reaction was significantly increased with butanol fraction in a dose-dependent manner. Peritoneal macrophages showed an increased phagocytic response on treatment with butanol fraction (100 μg/mL) as evidenced by its effect on nitroblue tetrazolium reduction and cellular lysosomal enzyme activity. All three fractions inhibited the production of NO and the release of TNF-α. Interleukin-10 production was significantly increased after treatment with butanol fraction. High-performance liquid chromatography analysis of the butanol fraction showed the presence of high concentration of catechin. The results suggested that butanol fraction of ethanol extract of A. catechu heartwood had immunomodulatory effects on non-specific, humoral, and cell-mediated immune functions. This study may be useful in validating the rationality of daily consumption of decoction of A. catechu and also its use in traditional medicine system. The study also suggests the possible use of A. catechu in the immunostimulatory herbal preparations. [Display omitted] •Butanol, Chloroform and Ethyl acetate fractions of Acacia catechu L. were studied for their immunomodulatory activities.•Butanol fraction stimulated antibody production, antibody producing cells in spleen and DTH.•The fraction also enhanced phagocytic activity and IL-10 production and suppressed TNF-α and NO production.•HPLC analysis of butanol fraction showed the presence of appreciable amount of catechin.•Study may be useful in validating the rationality of daily consumption of decoction of A. catechu and also its use in traditional medicine.

Chemically unique environment of endophytes makes them to have various adaptive mechanisms for survival. One of such mechanisms involves the production of pharmacologically significant plant-specific metabolites. In the present study, 26 endophytic fungi were isolated from stem of Bacopa monnieri (L.) Wettst. plants. All the isolates were screened for bacopaside production property by HPLC. Among these, the fungal isolate BmF 16 which was identified as Aspergillus sp. was confirmed for bacopaside N1 production ( m/z 796) by LC–MS/MS analysis. As the extract of BMF16 used in the study was prepared from the fifth generation of culture, the obtained result can be confirmed as due to fungal production of bacopaside. In addition, this property was identified only for one among the 26 fungi screened. As bacopaside N1 production in fungi has not yet been reported, the results of the study are novel.

As the demand for ready-made food is increasing, it is necessary to develop effective food packaging materials with antimicrobial activity to ensure microbiological safety of food. For this, polyvinyl alcohol (PVA) based active food packaging material reinforced with silver nanoparticles (AgNPs) was prepared by solvent casting. Here, ginger rhizome extract was used as the reducing agent for the rapid in situ reduction of AgNO 3 to AgNPs (gAgNPs) within the PVA matrix, under the influence of direct sunlight. Then the films were characterized by SEM, XRD, FTIR and UV-Vis spectrophotometry. Mechanical property analysis of PVA/gAgNP nanocomposite film showed its improved features when compared to neat PVA film. The presence of gAgNPs in the PVA/gAgNP film provided significant UV and light barrier properties together with profound antibacterial activity against the foodborne pathogen Salmonella Typhimurium and Staphylococcus aureus . Considering these excellent results, PVA/gAgNP film can expect to have promising food packaging application.