Biochemical Changes in Freshwater Prawn Macrobrachium rosenbergii During Larval Development

Abstract.— Quantitative changes in the protein, lipid and carbohydrate were studied in the early larval stages of developing freshwater prawn Macrobrachium rosenbergii reared under fed and starved conditions to understand the relative importance of these nutrients in energy metabolism of the growing larvae. Larvae obtained from several females were stocked into three 250-L tanks at a density of 30 larvae/L. The feeding regime consisted of newly hatched Artemia nauplii. Protein was always the major organic constituent followed by lipids and then carbohydrates of both fed and starved larvae. Protein levels of both fed and starved larvae increased during development, suggesting an important role in morphogenesis. The decline of lipid during the larval growth that was more rapid for starved larvae, suggests a probable utilization of lipid as the major metabolic source of energy. Carbohydrates formed less than 5 and 2.4% of the larval dry weight of fed and starved larvae, respectively, suggesting their limited role in larval metabolism.     

AHL signals induce rubrifacine production in a bruI mutant of Brenneria rubrifaciens

Several members of the bacterial genus Brenneria are pathogenic on different tree species. Cell-free extracts from the bacterial phytopathogens Brenneria rubrifaciens, B. salicis, and B. nigrifluens induced production of the red pigment rubrifacine in the B. rubrifaciens bruI insertional mutant Br-212. Analysis of the bruI locus identified an adjacent open reading frame, designated bruR, with homology to luxR. High-performance liquid chromatography and mass spectrometry analysis of ethyl acetate extracts from wild-type B. rubrifaciens and Escherichia coli expressing the bruI gene identified two acyl homoserine lactone (AHL) peaks, N-(3-oxohexanoyl)-homoserine lactone (3OC6HSL) and N-hexanoyl-homoserine lactone (C6HSL). Addition of synthetic 3OC6HSL and C6HSL at 10 μM to the bruI mutant, strain Br-212, induced rubrifacine production and the ability to elicit a hypersensitive reaction (HR) in tobacco leaves. Synthetic C6HSL was less effective at inducing pigment production than 3OC6HSL at 10 μM. The bruI mutant Br-212 did not produce detectable AHLs, indicating that C6HSL and 3OC6HSL are the major AHLs produced by this species. The AHLs N-heptanoyl-DL-homoserine lactone (C7HSL), N-octanoyl-DL-homoserine lactone (C8HSL), and N-(3-oxooctanoyl)-DL-homoserine lactone (3OC8HSL) also induced pigment production in Br-212 and restored its ability to elicit an HR in tobacco, suggesting that cross-talk with other bacterial species may be possible.     

电生功能水对南瓜贮藏期果腐病的防效试验

以电生功能水为研究对象,采用喷雾施药方法,研究了不同有效氯浓度的电功能水对南瓜果腐病防治效果。试验结果表明,电生功能水对南瓜果腐病的防治效果随有效氯含量的增加而提高,当电生功能水有效氯浓度为95 mg/L时效果最佳,防效达82.94%,与对照药剂50%多菌灵可湿性粉剂的防效89.41%不存在显著性差异。     

中国华北地区瓜类尖孢镰刀菌对咪鲜胺的敏感性及抗药突变株生物学性状研究

为明确中国华北地区瓜类尖孢镰刀菌Fusarium oxysporum Schl.对咪鲜胺的抗药性现状及抗药突变株的生物学性状,采用菌丝生长速率法,分别测定了采自北京、山东、河北等地未使用过咪鲜胺的112株瓜类尖孢镰刀菌对咪鲜胺的敏感性,并通过药剂驯化的方法获得尖孢镰刀菌抗咪鲜胺突变株。结果表明:咪鲜胺对112株瓜类尖孢镰刀菌的平均EC50值为（0.030 1±0.030 4）μg/mL,菌株频率呈连续单峰曲线分布,未发现敏感性明显下降的亚群体,因此,可将该EC50值作为瓜类尖孢镰刀菌对咪鲜胺的敏感基线。药剂驯化共获得7株抗咪鲜胺突变株,其抗性倍数介于6.2~26.8之间;突变株在菌丝生长速率、菌丝干重和致病力等方面均明显低于亲本菌株,差异显著;仅突变株HG13052701-R1的抗药性可以稳定遗传,其他6株抗咪鲜胺突变株的抗药性均不能稳定遗传。室内交互抗性测定结果表明,咪鲜胺仅与戊唑醇之间有交互抗性,与多菌灵和齅霉灵之间均无交互抗性关系。研究表明,瓜类尖孢镰刀菌在药剂选择压下可以形成抗咪鲜胺群体,具有低等抗药性风险。     

Challenges in developing and implementing a decision support systems (ETÇAP) in forest management planning: a case study in Honaz and Ibradı, Turkey

Decision support systems (DSSs) are indispensable tools in preparing a forest management plan for a better combination of multiple forest values. This study attempted to develop and explain a stand-based forest management DSS (Ecosystem-based multiple-use forest planning [ETÇAP]) comprising a traditional simulation, linear programming (LP), metaheuristics and geographic information system. The model consists of five submodels; traditional management approach to handle inventory data, an empirical growth and yield model, a simulation to conceptualize management actions, a LP technique to optimize resource allocation and a simulated annealing approach to directly create a spatially feasible harvest schedule. The ETÇAP model has been implemented in a comparative two case study areas; Denizli–Honaz and Akseki–Ibrad?. Both simulation and optimization models outperformed to the traditional management plan. The periodical change of growing stock, allowable cuts, carbon sequestration and water production are used as performance indicators. The results showed that more amount of wood could be harvested over time compared to traditional level of harvesting. It could be concluded that various management strategies allowed managers to stimulate more decision options for better outputs through intertemporal trade-offs of management interventions as the model provided tools to quantify forest dynamics over time and space. Challenges exist to establish the functional relationships between forest structure and values for better quantification and integration into the management plans.     

Production of monoclonal antibody against recombinant bovine sex-determining region Y (SRY) and their preferential binding to Y chromosome-bearing sperm

Separation of X and Y chromosome-bearing sperm is an appropriate method for the selection of desired sex of offspring to increase the profit in livestock industries. The purpose of this study was the production of a monoclonal antibody against recombinant bovine sex-determining region Y protein for separation Y sperm. The hybridoma cells from splenocytes of immunized female's balb/C mice and Sp2/0 cells were made. The binding affinity of our monoclonal antibody (mAbSRY2) was compared with mouse monoclonal SRY-15. The Western blot method indicated that mAbSRY2 successfully detected the rbSRY protein. The specificity and sensitivity of mAbSRY2 is comparable to SRY-15 commercially ones. The SRY gene in 100% of bull semen contains the Y chromosome that had the strongest binding affinity to mAbSRY2 was synthesized. In other words, the binding affinity of semen contains the X sperms near the negative control. In general, this immunological method can help to separate X from Y sperms. However, the mAbSRY2 is bind to Y-bearing sexed sperm, but in the future; the sexed sperms need to apply in farms.     

Chitosan nanoparticles enhance developmental competence of in vitro-matured porcine oocytes

Oxidative stress is inevitable as it is derived from the handling, culturing, inherent metabolic activities and medium supplementation of embryos. This study was performed to investigate the protective effect of chitosan nanoparticles (CNPs) on oxidative damage in porcine oocytes. For this purpose, cumulus–oocyte complexes (COCs) derived from porcine slaughterhouse ovaries were exposed to different concentrations of CNPs (0, 10, 25 and 50 µg/ml) during in vitro maturation (IVM). Oocytes treated with 25 µg/ml CNPs showed significantly higher levels of GSH, along with a significant reduction in ROS levels compared to control, CNPs10 and CNPs50 groups. In parthenogenetic embryo production, the maturation rate was significantly higher in the CNPs25 group than that in the control and all other treated groups. In addition, when compared to the CNPs50 and control groups, CNPs25-treated oocytes showed significantly higher cleavage and blastocyst development rates. The highest concentration of CNPs reduced the total cell number and ratio of ICM: TE cells in parthenogenetic embryos, suggesting that there is a threshold where benefits are lost if exceeded. In cloned embryos, the CNPs25 group, as compared to all other treated groups, showed significantly higher maturation and cleavage rates. Furthermore, the blastocyst development rate in the CNPs25-treated group was significantly higher than that in the CNPs50-treated group, as was the total cell number. Moreover, we found that cloned embryos derived from the CNPs25-treated group showed significantly higher expression levels of Pou5f1, Dppa2, and Ndp52il genes, compared with those of the control and other treated groups. Our results demonstrated that 25 µg/ml CNPs treatment during IVM improves the developmental competence of porcine oocytes by reducing oxidative stress.     

Potential protective effects of thiamine supplementation on the ruminal epithelium damage during subacute ruminal acidosis

In ruminants, the ruminal epithelium not only has the function of absorbing nutrients but also is an important tissue to prevent harmful substances in the rumen from entering the blood circulation. Thus, the normal function of ruminal epithelium is critical for ruminants. However, subacute ruminal acidosis induced by high-concentrate diets often damages the barrier function of ruminal epithelium in ruminants. Recently, many studies have shown that dietary supplementation with thiamine is an effective method to alleviate subacute ruminal acidosis. In order to provide theoretical reference for the in-depth study of subacute ruminal acidosis and the application of thiamine in the future, this review introduces the effects of subacute ruminal acidosis on morphological structure, inflammatory response, and tight junction of ruminal epithelium. In addition, this paper summarizes the role of thiamine in maintaining ruminal epithelial function of ruminants during subacute ruminal acidosis challenge.     

Starch digestion rates in multiple samples of commonly used feed grains in diets for broiler chickens

In this study the starch digestion rates in broiler chickens from 18 samples of 5 commonly used feed grains (sorghum, wheat, maize, barley, triticale) were determined. The methodology to determine starch digestion rates in poultry is detailed herein. Starch digestion rates were not significantly different (P = 0.128) across the 18 feed grains, which reflects the wide variations that were observed within a given feedstuff. Nevertheless, starch digestion rates in broiler chickens offered wheat-based diets were significantly more rapid by 56.0% (0.117 versus 0.075 min⁻¹; P = 0.012) than their sorghum-based counterparts on the basis of a pair-wise comparison. In descending order, the following starch digestion rates were observed: wheat (0.117 min⁻¹), barley (0.104 min⁻¹), triticale (0.093 min⁻¹), maize (0.086 min⁻¹), sorghum (0.075 min⁻¹). The implications of these findings are discussed as they almost certainly have implications for poultry nutrition and the development of reduced crude protein diets for broiler chickens.