Acute toxicity of alkali and alkaline earth metals on Rohu, Labeo rohita (Hamilton) egg and hatchlings

The acute toxicity of salts of alkali and alkaline earth metals, such as sodium (Na), potassium (K), calcium (Ca) and magnesium (Mg) were studied on the egg and larval stages of Indian major carp Labeo rohita (Hamilton). The acute toxicity experiments were conducted followed by the range finding bioassay tests. The experiments were conducted in triplicates. The cumulative percentage of dead or damaged eggs at the end of 6, 12, 18, 24, 36, 48, 60, 72 and 96 hours was recorded for the calculation of LC50. The increase in salt concentrations in water increased their toxicity and reduced the duration to damage 50% of the eggs. The eggs became smaller than their normal size and whitish before being damaged in the test solutions. Most of the exposed eggs and hatchlings tended to lay on the floor of the tank. The toxicity of the metals was in the order of K>Na>Mg>Ca. The 96 hours LC50 values were 3.25, 2.73, 28.9 and 20.52 ppm for sodium, potassium, calcium and magnesium, respectively

Thermodynamic and kinetic characteristics of an a-amylase from Bacillus licheniformis SKB4

An amylolytic bacterial strain, Bacillus licheniformis SKB4 produced maximum amylase at pH 6.5 at 42 °C, and at late stationary phase (24 h) of growth. Starch and peptone were found the best supporting carbon and nitrogen source with C:N ratio of 1:2 for amylase production. The purified enzyme was non-responsive to most of the metal ions except K+ and Mg++ (1.0 mM). The enzyme was stable and active at pH 6.5. The enzyme showed optimum temperature at 90 °C with 10 min of half life (t½) at 100 °C. The Q10 of the enzyme was 1.0. The thermodynamic principles like activation energy, free energy for substrate binding and transition state of the enzyme were found 31.53, 5.53 and -17.4 KJ/Mol of starch, respectively. The kinetic constant like Vmax, Km, K catand catalytic efficiency (Kcat/Km)for starch were found to be 1.04 μmol mg-1 min-1, 6.2 mg ml-1,2 × 103 S-1 and 3.22 × 102 ml mg-1 S-1,respectively. All these findings suggested that this amylase has unique characteristics for starch hydrolysis in respect to thermostability and kinetic properties

Ethnic Preparation of Haria, a Rice-Based Fermented Beverage, in the Province of Lateritic West Bengal, India

Haria is a rice-based fermented beverage that is popular among tribal and low income people in lateritic West Bengal and East-Central India. The principal ingredient of this beverage is low grade boiled rice (Oryza sativa L.), which is mixed with a traditional starter, called bakhar, and fermented within a heat-sterilized earthen pot for 3-4 days. The main aim of this study was to investigate the ethnobotanical importance and traditional process of haria preparation. The method adopted for this study was based on interactive questionnaires and laboratory experiments. It was found that the pH decreased during the course of fermentation with increased titratable acidity of 1.42%. The alcohol content was 2-3% (v/v) in the consumable beverages. This documentation will be useful for further exploitation of haria as a health drink

Characterization of an acidophilic α-amylase from Aspergillus niger RBP7 and study of catalytic potential in response to nutritionally important heterogeneous compound

An acidophilic α-amylase from Aspergillus niger RBP7 was purified after solid state fermentation on potato peel substrate. Molecular mass of the purified α-amylase was 37.5 kDa and it exhibited 1.4 mg/ml and 0.992 μ/mol/min Km and Vmax values, respectively. The enzyme was stable in the pH range from 2.0 to 6.0, at high NaCl concentration (3 M) and at temperatures between 40 °C and 70 °C. The enzyme showed an optimal activity at pH 3.0 and at 45 °C. The enzyme was inhibited by Hg2+ and was stable in the presence of different surfactants (Tween 60, Tween 80, and SDS at 1% level) and different inhibitory reagents (β-mercaptoethanol, phenylmethylsulfonyl fluoride, and sodium azide). This acidophilic amylase enzyme can digest heterogeneous food materials, i.e. the mixture of rice, fish, bread and curry with comparable activity to the commercial diastase enzymes available

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Bio-production of alkaline protease by Trichoderma longibrachiatum and Penicillium rubidurum using different agro-industrial products

Alkaline protease being active in neutral to alkaline pH has huge demands in food, detergent, leather and pharmaceutical industries. Its production from agro-industrial wastes not only lowers the production costs but also reduces the environmental problems. Hence, the present study aimed to search for new potential microbes, which can produce alkaline protease enzyme, to meet the industrial demands. In this study, 13 fungal spp. were isolated on potato dextrose agar medium (PDA) from mangrove soil through serial dilution, and then were streaked on the skim milk agar medium for qualitative screening of protease production. Out of 13 fungal spp.; only 7 spp. were able to produce proteolytic zones through the proteolytic assay. The Relative enzymatic index (REI) value (Zone diameter/Colony diameter) of all the fungal isolates that produced proteolytic zones on skim milk agar medium was evaluated. Only 2 fungal isolates which showed maximum REI value were selected, and then identified morphologically and molecularly as Trichoderma longibrachiatum (Accession no. MF144551) and by Penicillium rubidurum (Accession no. MF144561). Submerged fermentation was carried out using different agro industrial substrates to quantify for protease production, where the supernatants obtained were used for alkaline protease estimation. Among the different tested substrates, soybean powder and wheat bran were the most suitable substrates for maximum protease production by T. longibrachiatum (233.78±7.12 U/ mg) and P. rubidurum (228.61±11.13 U/ mg), respectively. The partial purified enzyme from these fungi showed maximum proteolytic potentials at pH 8.0 (P. rubidurum) and pH 9.0 (T. longibrachiatum), with optima temperature of 40 °C. Among the tested heavy metals, only Mn2+ expressed marginal enhancement of the protease enzyme activity

Estimation of tuberculosis incidence at subnational level using three methods to monitor progress towards ending TB in India, 2015–2020

Objectives We verified subnational (state/union territory (UT)/district) claims of achievements in reducing tuberculosis (TB) incidence in 2020 compared with 2015, in India.Design A community-based survey, analysis of programme data and anti-TB drug sales and utilisation data.Setting National TB Elimination Program and private TB treatment settings in 73 districts that had filed a claim to the Central TB Division of India for progress towards TB-free status.Participants Each district was divided into survey units (SU) and one village/ward was randomly selected from each SU. All household members in the selected village were interviewed. Sputum from participants with a history of anti-TB therapy (ATT), those currently experiencing chest symptoms or on ATT were tested using Xpert/Rif/TrueNat. The survey continued until 30 Mycobacterium tuberculosis cases were identified in a district.Outcome measures We calculated a direct estimate of TB incidence based on incident cases identified in the survey. We calculated an under-reporting factor by matching these cases within the TB notification system. The TB notification adjusted for this factor was the estimate by the indirect method. We also calculated TB incidence from drug sale data in the private sector and drug utilisation data in the public sector. We compared the three estimates of TB incidence in 2020 with TB incidence in 2015.Results The estimated direct incidence ranged from 19 (Purba Medinipur, West Bengal) to 1457 (Jaintia Hills, Meghalaya) per 100 000 population. Indirect estimates of incidence ranged between 19 (Diu, Dadra and Nagar Haveli) and 788 (Dumka, Jharkhand) per 100 000 population. The incidence using drug sale data ranged from 19 per 100 000 population in Diu, Dadra and Nagar Haveli to 651 per 100 000 population in Centenary, Maharashtra.Conclusion TB incidence in 1 state, 2 UTs and 35 districts had declined by at least 20% since 2015. Two districts in India were declared TB free in 2020