Isolation and partial characterization of bacteriophages infecting Vibrio harveyi from shrimp farm effluent water

Bacteriophage isolated from the semi-intensive culture of Pacific white leg shrimp Litopenaeus vannamei infects the luminous bacteria Vibrio harveyi. Lytic activity and lytic spectrum results revealed that the isolated phage had strong lytic activity in V. harveyi, V. parahaemolyticus, and V. vulnificus. Biofilm inhibition activity was performed against different pathogenic vibrios on high-density polyethylene (HDPE) template and the result revealed that the phage effectively inhibited the biofilm formation in V. harveyi. Spectrophotometric assay performed for lytic activity of the isolated phage in V. harveyi liquid culture showed that the phage significantly decreased the V. harveyi cell densities at different time intervals (P?<?0.05). To study the stability of phage at different temperature and pH revealed that the phage withstands the temperature ranged between 40 and 70 °C and the pH of 4 and 9 at a significant level (P?<?0.001). One-step growth curve depicted that the burst size gradually increased to a significant level and reached the maximum of 90% at 180 min (P?<?0.05). This study concluded that the isolated phage had specific activity against pathogenic V. harveyi infections.

     

Molecular characterization,tissue distribution of Follicle‐Stimulating Hormone (FSH) beta subunit and effect of kisspeptin‐10 on reproductive hormonal profile of Catla catla (Hamilton, 1822)

Gonadotropin (GTH) hormones are glycoprotein which stimulates gonadal maturation in vertebrates. Follicle stimulating hormone is involved in initiation of gametogenesis and regulation of gonadal growth. FSHβ has been cloned and characterized from the brain of Catla catla. The FSHβ full‐length of cDNA sequence of 523 bp comprised 3, 394 and 128 bp of 5′‐UTR, open reading frame (ORF) 3′‐UTR respectively. The coding region of C. catla FSHβ encoded a peptide of 130 amino acids. Phylogenetic analysis of C. catla FSHβ deduced amino acid sequence showed high similarity with Gobiocypris rarus followed by goldfish, Carassius auratus. The qPCR result shows that FSHβ mRNA is mainly expressed in pituitary while moderate and low expression was observed in testis and ovary respectively. Chitosan‐nanoconjugated kisspeptin‐10 (CK‐10) of particle size 125 nm, polydispersity index of 0.335 to 0.65 and zeta potential of ?34.95 mV were synthesized and evaluated at against naked kisspeptin‐10 for their reproductive hormonal profile. Treatment of fish with CK‐10 showed controlled and sustained surge of the reproductive hormones (FSH & LH) with peak at 12 h. The hormone levels of naked kisspeptin‐10 treated fish decline after 6 h. The sustained release of this CK‐10 will help in reducing maturation age, synchronization of ovulation and spawning in fish. This is the first report on use of chitosan‐nanoconjugated kisspeptin‐10 (CK‐10) for reproduction in fish.     

罗氏沼虾谷氨酰胺合成酶基因的克隆与表达

谷氨酰胺合成酶(glutamine synthetase, GS)是一种广泛分布在动植物体内的酶,并参与细胞多种代谢调控。在甲壳动物中,GS在能量代谢和渗透压调节过程中起着重要作用。实验克隆了罗氏沼虾GS基因。GS基因cDNA全长1 965 bp,开放读码框(ORF)为1 086 bp,编码361个氨基酸(aa),分子量大小为40.75 ku,等电点为5.81。进化树分析发现,罗氏沼虾GS基因与凡纳滨对虾、斑节对虾和中国明对虾GS聚为一支,氨基酸相似性达到95%。氨基酸多序列比对分析结果显示,罗氏沼虾GS属于无脊椎动物分支的GSⅡ群,有5个保守区域。实验对罗氏沼虾GS蛋白进行表达并制备了多克隆抗体。采用荧光定量PCR技术(qRT-PCR)和免疫印迹(Western blot)对罗氏沼虾蜕壳前后的不同组织GS表达进行检测。qRT-PCR结果显示,GS基因在所检测的8个组织中均有表达;蜕壳前,其相对表达量顺序为:肝胰脏肌肉胃肠鳃心脏脑血淋巴。蜕壳后和蜕壳前GS基因在组织中的差异表达比较结果显示,除了在肝胰脏表达下调外,其他7个组织都表达升高,其相对表达量的差异顺序为:脑鳃胃肠肌肉心脏血淋巴。Westernblot结果显示,蜕壳后GS蛋白在鳃和肌肉组织表达量上调,与其mRNA表达一致。此外,罗氏沼虾蜕壳后肝胰脏GS酶的活性和谷氨酰胺的含量下调,而其在鳃、肌肉和血淋巴中上调,结果与其基因表达一致。研究表明,GS基因在不同组织中表达的差异可能和罗氏沼虾的能量代谢、渗透压调节有关。     

Influence of weather factors on sorghum earhead bug Calocoris angustatus Lethierry incidence

Abstract

Weather parameters during the same week and one, two, three or four weeks before were correlated with the population of earhead bug, Calocoris angustatus on different earhead stages of two hybrids, CSH 5 and K‐Tall, in main and ratoon crops. The weather factors in the different weeks contributing to the insect population varied with the stage of earhead, the hybrid and the nature of the crop (main or ratoon). In the main crop, the insect population at pre‐flowering, milky, dough and maturity stage was influenced by weather parameters one week before, the same, two and three weeks before respectively. Morning relative humidity was important in both hybrids at all stages, with a few exceptions. In the ratoon crop, the pre‐flowering and maturity stage populations were influenced by the weather parameters of the same week. The populations at milky and maturity stage were influenced by parameters four weeks and one week before the observations respectively. The factors influencing the population on CSH 5 and K‐Tall varied. In most cases morning relative humidity had a positive influence.     

Development of chitosan conjugated DNA vaccine against nodavirus in Macrobrachium rosenbergii (De Man, 1879)

The protective efficacy of a DNA construct containing extra small virus antisense (XSVAS) gene of nodavirus encapsulated with chitosan nanoparticles (NPs) was investigated in giant freshwater prawn Macrobrachium rosenbergii (De Man, 1879). The delivery was carried out using oral and immersion methods. A plasmid concentration of 100 ng μL^?1 when conjugated with chitosan NPs was found to be more effective in increasing the survivability of the infected prawn. The particle mean size, zeta potential and loading efficiency percentage were 297 nm, 27 mV and 85%, respectively. The ability of the chitosan to form a complex with the plasmid was studied by agarose gel electrophoresis. The NPs were characterized by atomic force microscopy (AFM). Persistence study showed the presence of the DNA construct up to 30th day post‐treatment. The oral treatment was found to be better than the immersion treatment for delivery of the chitosan‐conjugated DNA construct. This is probably the first report on the delivery of nanoconjugated DNA construct in M. rosenbergii, against nodavirus.     

Micronutrient enrichment mediated by plant-microbe interactions and rice cultivation practices

A field experiment was conducted to evaluate the effect of different plant growth promoting microorganisms (PGPM) on micronutrient enrichment of rice crops grown under conventional (flooded) and SRI (System of Rice Intensification) practices. Significant differences were recorded among treatments and cultivation practices in terms of soil microbial activity reflected in enhanced nutrient uptake, enzyme activity, and yield. The Anabaena-based biofilm inoculants were particularly superior under both methods of cultivation, leading to 13–46% enhancement of iron and 15-41% enhancement of zinc in rice grains over uninoculated controls. SRI was found to be superior in terms of enhancing the concentration of zinc, copper, iron, and manganese (Zn, Cu, Fe and Mn), particularly in grains, and significant in increasing the activity of defense- and pathogenesis- related enzymes and yield parameters. This study illustrates the utility of cyanobacteria-based inoculants for both methods of rice cultivation and their significant interactions with the plant, leading to micronutrient enrichment of rice grains. Such formulations can complement the current biofortification strategies and help in combating the problems of malnutrition globally.     

Agroforestry,attitude towards risk and nutrient availability: a case study of south Indian farming systems

Introduction of two systems of agroforestry to the farmers portfolio is evaluated for their changes in cropping pattern, input use, income generation, farmers attitude towards risk and nutrient availability. Two different types of farmers are studied under both irrigated and dryland farming systems. Farm survey data collected from south Indian villages have been used with a mean-variance framework to identify the risk aversion levels of farmers. The results indicate that the risk-taking preferences of farmers should be given consideration in evaluating the impact of agroforestry systems. Among the two agroforestry systems analyzed, the one with drumstick is shown to increase the risk of crop production while the one with leucaena reduces the risk and enables farmers to invest in more risky cash crops. The impact of agroforestry on crop allocation, input use and income differs due to the differences in resource availability of farmers. The influence of agroforestry on nutrient availability of the farm households also differs based on the components of agroforestry, orientation of farming and the nature of farming systems. It is argued that design of agroforestry systems should consider differences in resource constraints in farming systems and risk attitudes of farmers towards their allocation decisions and that such considerations would largely enhance the successful adoption of agroforestry in developing countries.     

Antidiabetic potential of Barleria lupulina extract in rats

The methanol extract of aerial parts of Barleria lupulina orally tested at doses of 100, 200 and 300 mg/kg exerted significant antihyperglycemic effect in streptozotocin-induced hyperglycemia in rats [correction].