Peanut allergy is a major health problem worldwide. Detection of food allergens is a critical aspect of food safety. The VHH domain of single chain antibody from camelids, also known as nanobody (Nb), showed its advantages in the development of biosensors because of its high stability, small molecular size, and ease of production. However, no nanobody specific to peanut allergens has been developed. In this study, we constructed a library with random triplets (NNK) in its CDR regions of a camel nanobody backbone. We screened the library with peanut allergy Ara h 3 and obtained several candidate nanobodies. One of the promising nanobodies, Nb16 was further biochemical characterization by gel filtration, isothermal titration calorimetry (ITC), cocrystallization, and Western blot in terms of its interaction with Ara h 3. Nb16 specifically binds to peanut major allergen Ara h 3 with a dissociation constant of 400 nM. Furthermore, we obtained the Ara h 3-Nb16 complex crystals. Structure analysis shows the packing mode is completely different between the Ara h 3-Nb16 complex crystal and the native Ara h 3 crystal. Structural determination of Ara h 3-Nb16 will provide the necessary information to understand the allergenicity of this important peanut allergen. The nanobody Nb16 may have application in the development of biosensors for peanut allergen detection.

Abstract:The present study was concerned to assess the present status of biodiversity in the Bhairab river, Jessore with its conservation measures. The study was based on primary observations, questionnaire interviews with 50 fishers, focus group discussions with river bank community members and cross-check interviews with key informants. The study was conducted for a period four months from May to August, 2016. The objective of the study was to assess the fish biodiversity in the Bhairab river, understand the existing fishing practices of the river and to identify proper management strategies for the conservation of fish biodiversity. Results of the study revealed that three kinds of fishers were engaged in the Bhairab river namely, professional fishers; seasonal fishers and subsistence fishers. Seven types of fishing gears like seine net, gill net, cast net, push net, lift net, trap and hook and line were operated to fish by the fishers during the survey. A total of 39 species of fish were identified in the catches of the Bhairab River. There are degraded ecosystems and declining biodiversity have found during the study. According to survey, fishing pressure and over fishing were responsible for almost 38% loss and pollution and siltation caused about 27% loss of ecosystem. Around 21% and 14% loss of ecosystem were caused by urbanization and human encroachment, and the recreational activities respectively. These have been created a great impact on river ecology. As a result, the water quality is deteriorating day by day and the availability of fish species and other aquatic biodiversity is decreasing gradually. During the survey, 20 species was found at a risk of being endangered. From the survey, it was found that the overexploitation of fish was responsible for the 40% losses of biodiversity in the Bhairab River and water pollution caused 35% loss of biodiversity. Henceforth, river course change and habitat degradation resulted in 15% and 10% loss of biodiversity of the river respectively. This study was identified possible ways to achieve a rich fish biodiversity in the Bhairab River with social, economic and environmental aspects. The specific recommendations are included community based fisheries management, establishment of sanctuary, control of pollution, maintenance of fishing gears and the implementation of fish act for conservation of fish biodiversity of the Bhairab River.

Abstract:The research work was conducted to evaluate the effects of stocking density on growth, survival and production of mirror carp (Cyprinus carpio var. specularis) spawn in nursery pond for a period of 35 days. Three treatments differing in stocking density of hatchling viz., T 1 :172900 individuals/ha, T 2 :148200 individuals/ha and T 3 :123500 individuals/ha were employed each having three replicates. Fries were fed same diet in three different treatments consisting of (28.5%) at the rate of 6-10% of body weight. The Physico-chemical characteristics of pond water were measured weekly. The mean values of some water quality parameters such as temperature (°C) were 30.41 1.15 (T 1 ), 30.381.08 (T 2 ), 30.451.10 (T 3 ); transparency (cm) 40.000.90 (T 1 ), 39.740.51 (T 2 ), 39.930.70 (T 3 ); dissolved oxygen (mg/l) 6.790.45 (T 1 ), 6.710.38 (T 2 ), 7.020.29 (T 3 ); pH 7.550.18 (T 1 ), 7.670.16 (T 2 ), 7.620.20 (T 3 ) and alkalinity (mg/l) 116.200.64 (T 1 ), 99.360.45 (T 2 ), 96.470.93 (T 3 ) from 35 days respectively. Except alkalinity no significant value were found for parameters. Sampling was also done weekly. The mean value of final weight (g) was 0.350.004 (T 1 ), 0.420.008 (T 2 ), 0.590.006 (T 3 ). The survival rate of Cyprinus carpio var. specularis was 54.20% (T 1 ), 62.90% (T 2 ) and 74.56% (T 3 ) respectively. The highest survivability was found in T 3 . The production (kg/ha) of Cyprinus carpio var. specularis was 76.324.96 (T 1 ), 77.605.19 (T 2 ), 91.046.02 (T 3 ) respectively. Significantly (p< 0.05) highest production was found in T 3 .

Our study demonstrated that both recombinant MBP expression vectors significantly enhanced production. In addition, MBP tagged recombinant proteins can sometimes produce crystals. This strategy may be applied to other challenging proteins.

A study was undertaken to determine the effect of different dietary protein levels on growth, survival and production of Mystus cavasius (Hamilton-Buchanan 1822) with three experimental diets containing 29%, 32% and 35% protein level applied simultaneously to three treatments T1, T2 and T3 respectively each with three replications. The stocking density (1, 11, 150/ha), initial weight (3.00±00 g) and length (2.00±0.00 cm) of fish were same for all the treatments. No significant (P>0.05) difference was found for the mean values of water quality parameters. A suitable range of water quality parameters were recorded with the environment of experimental ponds. In terms of growth, production and survival, relatively highest performance was found in the treatment T3. After 180 days of rearing, average weight gain was 29.16±0.43 g, 31.17±0.30 g and 37.44±0.32 g with the above three different feeds, respectively. The average daily gain (ADG) and specific growth rate (SGR) of all treatments showed significant difference (P<0.05) and the highest value (0.21±0.04 and 1.43±0.01%) was found with the 35% dietary protein level containing diet. Feed conversion ratio (FCR) improved with increase of dietary protein. The findings of FCR were 2.97±0.02 at 29% protein level (T1), 2.64±0.02 at 32% protein level (T2) and 2.20±0.01 at 35% protein level (T3). The results of protein efficiency ratio (PER) values were fairly similar of 1.17±0.02 and 1.18±0.01 for 29% and 32% protein level containing diets respectively indicating low efficiency and the highest efficiency (1.30±0.01) was found with 35% protein level. The findings of condition factor in different treatments for Mystus cavasius were not significantly (P>0.05) varied with the treatments. Calculated values of condition factor were 1.04±0.00, 1.03±0.03 and 1.09±0.05 in treatment T1, T2 and treatment T3, respectively. In pond culture, the performance of treatment T3 was found to be better than the treatment T1 and T2. The production was of 3616±16.74 kg/ha in T3 during the culture period of six months. The best cost benefit ratio (CBR) value (1.98±0.02) was also found with treatment T3. The 35% dietary protein level with treatment T3 resulted in best growth performance and was probably adequate to meet the dietary protein needs of Mystus cavasius (Hamilton-Buchanan, 1822). Asian J. Med. Biol. Res. December 2020, 6(4): 659-673