Diversity of antimicrobial-resistant pathogens from a freshwater ornamental fish farm

The indiscriminate use of antimicrobials in aquaculture results in antibiotic selection pressure and proliferation of antimicrobial resistant (AMR) bacteria. Frequent assessment of antimicrobial resistance in aquaculture environment is inevitable so as to reduce the passage of clinically important AMR from aquatic to other environment. The present study analysed the antimicrobial resistance of pathogens associated with diseased koi carp and goldfish from an ornamental fish farm. Phenotypic and genotypic characterization of the recovered isolates from both fishes revealed significant pathogens in aquaculture such as Aeromonas, Edwardsiella tarda, Acinetobacter, Lactococcus, Citrobacter, Enterobacter and Comamonas. Shannon-Wiener diversity of koi isolates (2·359) was found to be higher than that of goldfish (1·864). Antibiotic susceptibility testing using disc diffusion with 47 antibiotics revealed significant resistance pattern of Acinetobacter, Comamonas, Klebsiella and Enterobacter from goldfish and Edwardsiella, Aeromonas, Lactococcus, Enterobacter and Acinetobacter from koi with higher multiple antibiotic resistance indexes (>0·3). The minimum inhibitory concentration of antibiotics for the major resistant isolates was found to be very high with >256 μg. All the isolates were susceptible to amoxicillin, kanamycin, cefepime, cefexime, cefotaxime, ceftazidime, doripenem, ciprofloxacin and norfloxacin, recommending their successful application in the farm. SIGNIFICANCE AND IMPACT OF THE STUDY: Antimicrobial resistance is a major threat faced in aquaculture industry. The current study provides baseline information regarding the antibiotic resistance patterns of diverse pathogens recovered from ornamental koi carp and goldfish. The higher MAR index of pathogens and greater MIC of antibiotics for the resistant isolates highlighted the intense use of antibiotics in aquaculture farm. The potential of the pathogens to exhibit resistance even towards the new generation antibiotics remind the need of prudent use of antibiotics and continuous monitoring and surveillance programmes.

Quality protein maize based muffins: influence of non-gluten proteins on batter and muffin characteristics

Quality protein maize (QPM) is nutritionally improved maize which has twice the amount of lysine and tryptophan than normal maize. The present study evaluated the effect of different proteins namely egg white proteins (EWP), casein, whey protein isolate, soy protein isolate (SPI) on characteristics of gluten free QPM based muffins. QPM muffins without any added protein served as control and muffins prepared using wheat and EWP served as reference. Effect of addition of different proteins on pasting properties revealed that the thermal stability of QPM flour increased as indicated by decrease in breakdown viscosity. The effect of added proteins on QPM muffin-making properties was evaluated for rheology of batter and physicochemical, texture, color and sensory characteristics of muffins. Dynamic rheology showed that storage modulus (G') and loss modulus (G″) of batter with SPI was the highest while batter with EWP showed lowest value. QPM-EWP muffins were softer, chewy and springier and had more specific volume than control muffins and were comparable to reference muffins. Inclusion of all proteins increased L* values (lightness) and decreased a* (redness/greenness) and b* (yellow/blueness) values of QPM based muffins. Sensory analysis revealed that gluten free QPM muffin prepared from EWP were acceptable with a sensory score of 7.97 which was comparable to reference muffins (8.03).

Organic bistable memory devices based on MoO3 nanoparticle embedded Alq3 structures

Organic bistable memory devices were fabricated by embedding a thin layer of molybdenum trioxide (MoO₃) between two tris-(8-hydroxyquinoline)aluminum (Alq₃) layers. The device exhibited excellent switching characteristics with an ON/OFF current ratio of 1.15 × 10³ at a read voltage of 1 V. The device showed repeatable write-erase capability and good stability in both the conductance states. These conductance states are non-volatile in nature and can be obtained by applying appropriate voltage pulses. The effect of MoO₃ layer thickness and its location in the Alq₃ matrix on characteristics of the memory device was investigated. The field emission scanning electron microscopy (FE-SEM) images of the MoO₃ layer revealed the presence of isolated nanoparticles. Based on the experimental results, a mechanism has been proposed for explaining the conductance switching of fabricated devices.