Amylases are starch degrading enzymes which are produced by plants, animals and microorganisms. Amylases produced by microorganisms have a wide range of industrial applications such as in pharmaceutical, food, textile and paper industries. However, there are still limitations in the isolation of amylase producing microorganisms. The objective of this study was to isolate the potent amylase producing Bacillus sp. from soil samples and evaluate their abilities for inhibiting the aflatoxin producing Aspergillus flavus. In this study, 30 soil samples were used. For the screening and identification of Bacillus strain, morphological and biochemical tests were performed. Iodine assay was done to screen the potent amylase producers. Two parameters (pH and temperature) were used to optimize the cultural conditions for the production of amylase. To determine the total reducing sugar, dinitrosalicylic acid (DNS) assay was used. Altogether 29 colonies were selected and identified as Bacillus spp out of which 16 were selected to determine enzyme activity by cup plate method. Four isolates (DK9, DK10, IM4 and KD7) showing highest amylolytic activities (16 mm, 12 mm, 14 mm and 14 mm zone of hydrolysis) were subjected for further study. Isolate KD7 showed the highest amylolytic activity (0.19 U/mL) compared to other isolates. Maximum amylase production was found at pH 6 and temperature 50° C (0.19 U/mL). Among these 4 isolates, DK9 and KD9 showed strong antagonistic activity against Aspergillus flavus while DK10 and IM4 showed moderate antifungal activities. Thus, the bacterial isolate KD7 was identified as the most potent strain for maximum amylase production.
Human–wildlife conflict is a challenging issue that requires the attention of conservationists worldwide. Habitat fragmentation and encroachment reduce the abundance of prey species, and an increase in the number of predators leads to a higher risk of conflict with large cats such as leopards, jeopardizing conservation efforts. This study explored the spatio-temporal pattern of the human–leopard conflict in Bardia National Park, Nepal, from 2000 to 2020. To analyze the conflict with leopards, we used data (compensation cases filed in the park) from the buffer zone management office, the National Trust for Nature Conservation (NTNC), and the Department of National Park and Wildlife Conservation (DNPWC). Leopard attacks on livestock are increasing exponentially, with 3335 livestock killed in 2652 attacks occurring during the study period. Although livestock depredation by leopards occurred all over the park, the southern cluster has most documented livestock damage (64.01%). The eastern and northern clusters reported fluctuating and dispersed predation events, respectively. Our spatial analysis indicated no effect of topography (slope) on livestock depredation by leopards. We recorded the highest number of leopard attacks and predation during the dry winter season when the nights are longer and livestock remain in their sheds. This carnivore mostly limited its prey to small-sized livestock (95.77%) such as goats, sheep, and pigs, whereas attacks on large-sized (cow and buffalo) livestock were least frequent. Among small-sized livestock, goats are the most predated (66.92%), followed by pigs (20.30%), in all seasons. The escalating human–leopard conflict in BNP is thus a severe threat to conservation efforts as the park has already invested a substantial amount of money (approx. USD 80,000) compensating for livestock lost in leopard attacks over the last two decades. Improving habitat conditions to reduce competition inside the park, developing an insurance scheme for livestock and humans, providing support for upgraded sheds, and the development of practical and feasible strategies that focus on specific animals and clusters of the national park are needed to reduce conflicts to maintain the co-existence between wildlife and human beings.
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