Probiotic Potential And Safety Characterization Of Enterococcus Hirae G24 Isolated From Indigenous Raw Goat Milk

In this paper, an investigation on lactic acid bacterial isolates from ethnic goat raw milk samples were examined for their probiotic potential and safety parameters. For this purpose, isolated bacterial cultures were screened based on certain parameters viz., sugar fermentation, tolerance to temperature, salt, low pH, bile salts, and phenol resistance. After that, these bacterial cultures were more estimated in vitro for auto-aggregation, cell surface hydrophobicity, response to simulated stomach duodenum channel, antibiotic resistance, and antimicrobial activity. Besides, probiotic traits show the absence of gelatinase and hemolytic activity supports its safety. The isolate G24 showed good viability at different pH, bile concentration, phenol resistance and response to simulated stomach duodenum passage but it did not show gelatinase and hemolytic activities. Isolate G24 was susceptible to amikacin, carbenicillin, kanamycin, ciprofloxacin, co-trimazine, nitrofurantoin, streptomycin, and tetracycline. Isolate G24 also exhibited antimicrobial action against five common pathogenic bacteria, such as Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Listeria monocytogens, and Salmonella typhimurium. It displayed the maximum auto-aggregation, cell surface hydrophobicity to different hydrocarbons. Following molecular characterization the isolate G24 was identified as Enterococcus hirae with 16S rRNA gene sequencing and phylogeny. E. hirae G24 bears the excellent properties of probiotics.

The role of linoleic acid, palmitic acid and leucine in lipstatin biosynthesis by streptomyces toxytricini.

Lipstatin, a new and very potent inhibitor of pancreatic lipase, was isolated from the Streptomyces toxytricini. Lipstatin contain a beta lactone structure that probably account for the irreversible lipase inhibition. As per the biosynthetic pathway the role of linoleic acid, palmitic acid and leucine in lipstatin biosynthesis by Streptomyces toxytricini was studied. Different oils were analyzed to measure the concentration of the linoleic acid and palmitic acid in the medium, and then the selected oil was used as media ingredients. While leucine was used as a media ingredient as well as feeding nutrient in the production medium. The lipstatin production depends on linoleic acid palmitic acid and leucine concentration as per biochemical pathway. But in present study it was observed that in control media the lipstatin activity was 1.108 mg/g while when we use linoleic acid and palmitic acid as media ingredients then the activity was 0.610 mg/g. Similarly in case of leucine was used as ingredient as well as feeding solution the maximum activity was observed 0.810 mg/g at 264 h. Thus, it may conclude that their is no significant impact of linoleic acid, palmitic acid and leucine as media ingredients and as a feeding solution on lipstatin production.

Antagonistic effect of fluorescent pseudomonads against Macrophomina phaseolina that causes charcoal rot of groundnut.

Maximum colony growth inhibition was observed due to Pseudomonas PS2 (74%) as compared to PS1 (71%) on trypticase soy agar (TSM) plates after 5 days of incubation. Light and scanning electron microscopic examination showed hyphal coiling, vacuolation, coagulation and granulation of cytoplasm resulting in lysis of hyphae of M. phaseolina by pseudomonads. Cell free culture filtrates of strains PS1 and PS2 restricted the growth of mycelium of M. phaseolina. PS1 and PS2 caused maximum colony growth inhibition by 57 and 61% respectively at 20% concentration of culture filtrate after 4 days of incubation. Volatile substances produced by PS1 and PS2 also inhibited the colony growth of M. phaseolina by 25 and 32%, respectively. Inhibitory effect of volatile substances, however, decreased with advancing in incubation period. Colony growth of M. phaseolina was significantly decreased by PS1 and PS2 as compared to control both in iron- sufficient and iron-deficient conditions. PS2 showed higher antagonistic activity than PS1, as evidenced by pronounced colony growth inhibition.

Effect of metal ions on growth of Pseudomonas aeruginosa and siderophore and protein production.

Pseudomonas aeruginosa (GRC1) isolated from potato rhizosphere, grew better on succinate medium than tryptic soy medium and produced hydroxamate type of siderophore in iron-deficient succinate medium. When the strain GRC1 was grown in the presence of different metal ion compounds, viz. ZnSO4, MnSO4, MnCl2 and FeCl3 at 6 and 12 microM concentrations individually, ZnSO4 (12 microM) promoted siderophore production but suppressed the growth and protein content of test organism. MnCl2 and FeCl3 (12 microM) enhanced the growth, whereas MnCl2 and MnSO4 (12 microM) induced protein contents of strain GRC1.

Effect of some antibiotics on Macrophomina phaseolina, a charcoal rot fungus of soybean.

Effect of agrimycin-100, ampicillin, griseofulvin and tetracycline on colony growth of Macrophomina phaseolina, incitant of charcoal rot of soybean has been studied in vitro. Amongst them tetracycline posed most effective inhibiting the growth by 73.9% at 1000 micrograms/ml concentration. On the basis of effectiveness antibiotics have been listed as tetracycline greater than ampicillin greater than griseofulvin greater than agrimycin-100.