Dynamic viscoelastic, calorimetric and dielectric characteristics of wheat protein isolates

Dynamic oscillatory rheology of two wheat protein isolate (Prolite 100 and Prolite 200) doughs (≈48% moisture content, wet basis) were studied over a frequency range of 0.1–10 Hz during temperature sweep from 20 to 90 °C at a heating rate of 2 °C/min. Both doughs behaved similarly during heating; showed a threshold value and increased sharply, thereafter. Prolite 200 dough had a higher elastic modulus (G′) and lower phase angle (δ) whereas Prolite 100 showed a distinct gel point at 52.2 °C followed by significant increase up to 90 °C. Rheological data of doughs after isothermal heating at 90 °C for 15 min followed by cooling to 20 °C resulted in strong mechanical strength. However, Prolite 100 dough showed more viscoelastic characteristics with significant transformation from liquid-like to solid-like behavior after heating than Prolite 200. Thermal analysis of isolates indicated distinct endothermic peaks in wider temperature range (50–130 °C) at various moisture levels. Lower temperatures could be associated with denaturation of various fractions of proteins whereas higher temperature linked to glass transition temperature of isolates. SDS–PAGE did not show any clear distinction among protein subunits between two isolates. Dielectric measurements of isolates at frequencies from 500 to 3000 MHz and temperature range between 30 and 80 °C indicated Prolite 200 had higher dielectric constant (ε′) and loss factor (ε″) than Prolite 100. Isolates showed significant changes in dielectric properties above 50 °C indicating protein denaturation and supported rheological and calorimetric data.     

Characterization of fate and transport of isoxaflutole, a soil-applied corn herbicide, in surface water using a watershed model

The objective of this study is to conduct a comprehensive assessment of the transport of isoxaflutole and RPA 202248 and their accumulation potential in semistatic water bodies, using a distributed watershed scale model and observed water quality data. A conceptual model was developed to characterize the fate and transport of isoxaflutole residues to and in surface water. The soil and water assessment tool (SWAT), a continuous daily time-step watershed model, was used to simulate the processes identified in the conceptual model. Monitoring data were available for a number of surface water bodies within the major product use area as a result of extensive and intensive residue monitoring. Detailed product use information at the zip-code level was obtained through dealer sales and a grower survey. The hydrologic and chemical transport results from the SWAT model were validated by comparison to available monitoring data from selected water bodies. Upon validation, the model was used to simulate the fate of isoxaflutole-derived residues in the water bodies using long-term historical weather data. The results from this investigation indicate no evidence of long-term accumulation of isoxaflutole and its metabolite RPA 202248 in semistatic water bodies.     

Detection of Fowl Adenovirus Associated With Hydropericardium Hepatitis Syndrome by a Polymerase Chain Reaction

Hydropericardium hepatitis syndrome HHS), previously unknown in the broiler industry, is an emerging disease that causes severe hydropericardium. A polymerase chain reaction PCR) was developed to detect the fowl adenovirus FAV) associated with HHS. The virus from infectedl ivers was purified, with confirmation by electron microscopy and experimental infection. Methods were developed to isolate the viral DNA from purified virus and infected tissues. Available sequence data on the hexon gene of fowl adenoviruses and other adenoviruses were aligned to determine the conserved and variable regions. Primers were constructed from the alignment data. The amplified fragment consisted of the variable region of the hexon gene flanked by conserved primer sites. Optimum conditions were standardized to achieve the amplification of the desired fragment. As expected, the amplified product was found to be of 0.7 kg size. The nucleotide sequence analysis confirmed the specific nature of the product. Amplification of the specific product could be obtained not only from the DNA isolated from the purified virus but also from the total DNA extracted from infected tissues. The PCR was useful for the detection of FAV associated with HHS.     

From scientific obscurity to conservation priority: Research on angler catch rates is the catalyst for saving the hump‐backed mahseer Tor remadevii from extinction

1. The mahseer (Tor spp.) fishes of South and Southeast Asia are iconic megafaunal species that are highly valued by recreational anglers. Knowledge on their populations is limited owing to the challenges associated with sampling these large‐bodied fishes (>50 kg) in remote monsoonal rivers.
2. Despite its global iconic status among recreational anglers, the hump‐backed mahseer of the Cauvery River (South India) lacked a valid scientific name and was on a trajectory towards extinction until its rapidly declining population status was established by analyses of angler catch records.
3. Angling records from 1998 to 2012 showed that mahseer catch rates had increased in this period. The resulting publication in Aquatic Conservation (AQC) highlighted the positive role of catch‐and‐release angling in providing information on data‐poor species. However, further analyses showed that these catches comprised not one but two distinct phenotypes.
4. Before 1993, all mahseer captured were hump‐backed; since then, a blue‐fin phenotype appeared in catches and subsequently dominated them. These results triggered further studies indicating that the hump‐backed mahseer was the endemic Tor remadevii and that the blue‐fin was the invasive Tor khudree, introduced in 1976 and then stocked periodically from hatcheries.
5. The initial AQC publication successfully demonstrated the high value of organized angling as a monitoring tool for data‐poor fishes and its application to assessing the temporal population patterns of large‐bodied fishes in monsoonal rivers. It was also the catalyst for initiating subsequent studies on T. remadevii that, together, enabled its recent assessment as ‘Critically Endangered’ on the International Union for Conservation of Nature (IUCN) Red List. In the absence of the AQC paper, and the subsequent studies that it triggered, it is highly probable that the species would have remained on a trajectory towards rapid extinction. Instead, the first major steps to safeguarding its future have been taken.

     

Larval rearing of hilsa shad,Tenualosa ilisha (Hamilton 1822)

Hilsa, Tenualosa ilisha has received much attention for culture due to decline of the natural population. Lack of knowledge on larval rearing is the bottleneck for its culture. This study was aimed at developing larval rearing protocols for hilsa shad. Hilsa larvae (4 days old, 4.76 ± 0.06 mm/0.49 ± 0.01 mg) were stocked in fibreglass‐reinforced plastic tanks (1.7 m³ water volume) at 300, 600 and 1,200 nos/m³ in triplicates in three experimental systems viz., E‐I (circular, 0.567 m water depth), E‐II (circular, 0.962 m water depth) and E‐III (rectangular, 0.567 m water depth) and reared for 46 days. The larvae were supplied with Chlorella vulgaris, Brachionus calyciflorus, mixed phytoplankton and mixed zooplankton during 4–50, 6–25, 8–50 and 26–50 days of their age respectively. In each system, higher (p < 0.05) fry survival at 300 nos/m³ than in higher densities indicates density dependent stress. Circular tanks showed higher survival (13.3%–61.31%) than in rectangular tanks (6.88%–27.26%) in each stocking density, indicating the importance of tank shape for rearing. Water depth affected fry survival in circular tanks (E‐I and E‐II) at 300 nos/m³; at 0.962 m depth, survival was higher (61.31%, p < 0.05) than that of 0.567 m depth (49.93%). Good fry survival was achieved through feeding the larvae initially with Chlorella followed by co‐feeding with Brachionus, mixed phytoplankton and zooplankton and rearing in circular tanks at 300 nos/m³ densities at 1 m depth. This first‐ever larval rearing protocol is useful for mass production of fry to support hilsa aquaculture in future.