Probiotic Paenibacillus polymyxa HGA4C and Bacillus licheniformis HGA8B combination improved growth performance, enzymatic profile, gene expression and disease resistance in Oreochromisniloticus.

Bacterial consortium containing two bacterial strains such as Paenibacillus polymyxa HGA4C and Bacillus licheniformis HGA8B incorporated in the diet of Oreochromis niloticus at a concentration of 1 × 106 CFU g-1 (PB1) and 1 × 108 CFU g-1 (PB2) revealed the probiotic potentials of the bacterial combination. The probiotic feed enhanced the growth performance, digestive enzymes, and antioxidant enzymes in the liver and intestine. Probiotic mediated growth enhancement was further substantiated by the up-regulation of genes such as GHR-1, GHR-2, IGF-1, and IGF-2 and the up-regulation of immune-related genes viz. TLR-2, IL-10, and TNF-α were also significantly modulated by probiotics supplementation. The intestinal MUC 2 gene expression revealed the mucosal remodification and the disease resistance of the fish challenged with Aeromonas hydrophila (MTCC-1739) was improved by the probiotic supplementation. Based on these results the new probiotic supplementation feed can be possibly marketed to help aquaculture farmers to alleviate many of the problems associated with fish farming.

Surface functionalization of central venous catheter with mycofabricated silver nanoparticles and its antibiofilm activity on multidrug resistant Acinetobacter baumannii.

The mycofabrication of silver nanoparticles (AgNPs) through green chemistry protocol is an advanced methodological progress in medical nanotechnology. Mycofabricated AgNPs are less toxic due to an aura of biomolecules around the nanoparticles. Hence the mycofabricated AgNPs can be used for clinical applications. The present study explores the antibiofilm activity of mycogenerated AgNPs, which were synthesized by the enzymatic reduction of silver nitrate using the marine algicolous endophytic fungus Penicillium polonicum ARA10. The mycogenerated AgNPs showed very specific and potent bactericidal activity against Acinetobacter baumannii. Anti-A.baumannii activities of mycogenerated AgNPs on planktonic as well as biofilm embedded cells were explored. The physical impact of synthesized AgNPs on A.baumannii was investigated by scanning electron microscopy and fluorescence microscopy. A bionanocomposite coating for the central venous catheter (CVC) was formulated using the mycogenerated AgNPs and polydopamine. The bionanocomposite surface was characterized by field emission scanning electron microscopy, water contact angle measurement, and Raman spectroscopy. The results showed that the mycogenerated AgNPs have potent antibiofilm activity on biofilms of A.baumannii. The scanning electron microscopy (SEM) and fluorescence microscopy images showed noticeable aberrations on the ultrastructure of A.baumannii. The SEM and FE-SEM images of biofilms on the surface of CVC samples proved that the AgNPs at minimum bactericidal concentration could destroy the structure of biofilms and lyses the bacterial cell. Thus, the present study establishes a new way to the development of 'antibacterial surfaces' based on mycogenerated AgNPs.

Catechin rich butanol fraction extracted from Acacia catechu L. (a thirst quencher) exhibits immunostimulatory potential.

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.

Antagonism Against Fish Pathogens by Cellular Components/Preparations of Bacillus coagulans (MTCC-9872) and It's In Vitro Probiotic Characterisation.

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.

Efficient visible light induced synthesis of silver nanoparticles by Penicillium polonicum ARA 10 isolated from Chetomorpha antennina and its antibacterial efficacy against Salmonella enterica serovar Typhimurium.

The green synthesis of silver nanoparticles (AgNPs) using biological systems such as fungi has evolved to become an important area of nanobiotechnology. Herein, we report for the first time the light-induced extracellular synthesis of silver nanoparticles using algicolous endophytic fungus Penicillium polonicum ARA 10, isolated from the marine green alga Chetomorpha antennina. Parametric optimization, including the concentration of AgNO3, fungal biomass, ratio of cell filtrate and AgNO3, pH, reaction time and presence of light, was done for rapid AgNPs production. The obtained silver nanoparticles (AgNPs) were characterized by UV-Visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy and Transmission electron microscopy (HRTEM-EDAX). The AgNPs showed a characteristic UV-visible peak at 430 nm with an average size of 10-15 nm. The NH stretches in FTIR indicate the presence of protein molecules. The Raman vibrational bands suggest that the molecules responsible for the reduction and stability of AgNPs were extracellular proteins produced by P.polonicum. Antibacterial evaluation of AgNPs against the major foodborne bacterial pathogen Salmonella enterica serovar Typhimurium MTCC 1251, was assessed by well diffusion, Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assay. Killing kinetic studies revealed complete killing of the bacterial cells within 4 h and the bactericidal nature of synthesized nanoparticles was confirmed by fluorescent microscopy and scanning electron microscopy. Furthermore, the bactericidal studies with Transmission electron microscopy (TEM) at different time intervals explored the presence of AgNPs in the cell wall of S.Typhimurium at about 30 min and the complete bacterial lysis was found at 24 h. The current research opens an insight into the green synthesis of AgNPs and the mechanism of bacterial lysis by direct damage to the cell wall.

Green synthesized silver nanoparticles by marine endophytic fungus Penicillium polonicum and its antibacterial efficacy against biofilm forming, multidrug-resistant Acinetobacter baumanii.

Acinetobacter baumanii, a gram-negative, non-motile, encapsulated coccobacillus which causes infections worldwide. The objective of this study was to find a fungal strain that could be utilized to biosynthesize antibacterial silver nanoparticles (AgNPs) against Acinetobacter baumanii. The present investigation explains rapid and extracellular biosynthesis of silver nanoparticles by the algicolous endophytic fungus, Penicillium polonicum, isolated from the marine green alga Chetomorpha antennina. The obtained silver nanoparticles were characterized by UV-Vis spectroscopy, Raman spectroscopy, Fourier transformation infrared (FTIR), and Transmission electron microscopy (TEM). The SNPs showed a characteristic UV- visible peak at 430 nm with an average size of 10-15 nm. As evident from the FTIR and Raman spectra, possibly the protein components of fungal extract have caused the reduction of silver nitrate. Parametric optimization, including the concentration of AgNO3, ratio of cell filtrate and AgNO3, fungal biomass, reaction time, pH, and presence of light, was done for rapid AgNPs production. The antibacterial efficacy of AgNPs against multi-drug-resistant, biofilm-forming Acinetobacter baumanii, was evaluated by well diffusion assay. The Minimum inhibitory concentration (MIC) of AgNP was 15.62 µgml-1 and the minimum bactericidal concentration (MBC) was 31.24 µgml-1. Killing kinetic assay revealed complete killing of the bacterial cells within 6 h. Log reduction and percent survival of bacterial cells were analyzed from killing kinetic study. Bactericidal nature of synthesized nanoparticles was confirmed by fluorescent microscopical analysis. The effect of AgNPs on the ultrastructure of bacterial pathogen was evaluated by Transmission electron microscopy.

Antibacterial activity and probiotic characterization of autochthonous Paenibacillus polymyxa isolated from Anabas testudineus (Bloch, 1792).

Microbial fish pathogens are prevalent in aquaculture. Control of bacterial fish pathogens is important and bio control of pathogenic bacteria is a novel field of study. The aim of this study was to evaluate the antagonistic activity of bacteria isolated from Anabas testudineus against potent fish pathogens. The cellular components/preparations and filtered cell free culture supernatants were effective against six fish pathogens. Altogether 110 strains were isolated from fish proximal and distal intestine, out of which 10 strains were selected through well diffusion method. From them a strain HGA4C having prominent antimicrobial activity was selected as candidate probiotic strain. The whole-cell product, heat-killed whole-cell product and the filtered broth were exhibited bactericidal activity against the tested pathogens. Among them cell free culture supernatant showed maximum inhibition. In addition, isolated candidate probiotic bacterium was capable of producing extracellular enzymes important for the digestion of food ingredients and was effectively grown in fish mucus obtained from Oreochromis niloticus. The strain tolerated gradient of bile juice secreted by the host and effectively produced biofilm. Analysis of 16S rDNA sequence revealed that isolated strain HGA4C was Paenibacillus polymyxa (MF457398.1). Furthermore intraperitoneal injection of the bacterium did not induce any pathological anomalies or mortalities in Oreochromis niloticus and disclosed the safety of this bacterium as a candidate probiotic in aquaculture.

Antibacterial activity of autochthonous bacteria isolated from Anabas testudineus (Bloch, 1792) and it's in vitro probiotic characterization.

Antimicrobial potentials of bacteria isolated from Anabas testudineus have been evaluated through in vitro antagonistic activity against potent fish pathogens. The cellular components and filtered culture medium were effective against six fish pathogens. Altogether 110 strains were isolated from the fish gut, out of which 10 strains were selected through well diffusion method. From them, a strain HGA8B having cumulative maximum score was selected as candidate probiotic. The whole-cell product, heat-killed whole-cell product, Ethyl acetate extract, and the filtered broth were exhibited bactericidal activity against the tested pathogens. In addition, the isolated bacterium was capable of producing extracellular enzymes important for the digestion of food materials and was capable of growth in fish mucus from Oreochromis niloticus. The strain tolerated bile juice secreted by the host and effectively produced biofilm. Analysis of 16S rDNA sequence revealed that isolated strain HGA8B was Bacillus sp. (MF351637). Furthermore, intraperitoneal injection of the bacterium did not induce any pathological signs, symptoms or mortalities in Oreochromis niloticus and revealed the safety of this bacterium as a candidate probiotic in aquaculture.