不同碳氮有机物料对有机菜田土壤细菌多样性的影响

通过模拟试验,利用聚合酶链式反应-变性梯度凝胶电泳法(PCR-DGGE),研究了施入不同碳氮有机物料(秸秆、苜蓿、有机肥、尿素)56d后,有机生产系统菜田土壤细菌群落结构的特征。结果表明,常规和有机生产系统土壤的细菌群落结构有明显差异。由DGGE图谱ShannonWiener多样性指数分析得知,有机背景处理的细菌多样性整体高于常规背景处理,且有机生产系统土壤加秸秆处理(OS)多样性最高,加入尿素后细菌多样性降低,相反,加入苜蓿后细菌多样性升高。非加权组平均法(UPGMA)聚类分析将常规和有机背景土壤分为两大族群。DGGE条带测序和系统进化树表明,30个条带归属为Proteobacteria、Acidobacteria、Actinobacteria、Firmicutes、Verrucomicrobia。常规土壤加苜蓿(CA)处理出现的特征性条带B13与有机背景处理的共有条带B28分别与Bacillus属和Pseudomonas假单胞菌属同源性最高。     

Germline mutations in genes within the MAPK pathway cause cardio-facio-cutaneous syndrome

Cardio-facio-cutaneous (CFC) syndrome is a sporadic developmental disorder involving characteristic craniofacial features, cardiac defects, ectodermal abnormalities, and developmental delay. We demonstrate that heterogeneous de novo missense mutations in three genes within the mitogen-activated protein kinase (MAPK) pathway cause CFC syndrome. The majority of cases (18 out of 23) are caused by mutations in BRAF, a gene frequently mutated in cancer. Of the 11 mutations identified, two result in amino acid substitutions that occur in tumors, but most are unique and suggest previously unknown mechanisms of B-Raf activation. Furthermore, three of five individuals without BRAF mutations had missense mutations in either MEK1 or MEK2, downstream effectors of B-Raf. Our findings highlight the involvement of the MAPK pathway in human development and will provide a molecular diagnosis of CFC syndrome.     

Sorghum Pasta and Noodles: Technological and Nutritional Aspects

Plant Foods for Human Nutrition - Sorghum is a major cereal crop with various agronomic advantages, contains health-promoting compounds and is gluten-free. There is a growing tendency to use...     

Differentiation of embryonic stem cells to insulin-secreting structures similar to pancreatic islets

Although the source of embryonic stem (ES) cells presents ethical concerns, their use may lead to many clinical benefits if differentiated cell types can be derived from them and used to assemble functional organs. In pancreas, insulin is produced and secreted by specialized structures, islets of Langerhans. Diabetes, which affects 16 million people in the United States, results from abnormal function of pancreatic islets. We have generated cells expressing insulin and other pancreatic endocrine hormones from mouse ES cells. The cells self-assemble to form three-dimensional clusters similar in topology to normal pancreatic islets where pancreatic cell types are in close association with neurons. Glucose triggers insulin release from these cell clusters by mechanisms similar to those employed in vivo. When injected into diabetic mice, the insulin-producing cells undergo rapid vascularization and maintain a clustered, islet-like organization.     

Effects of no‐take area size and age of marine protected areas on fisheries yields: a meta‐analytical approach

Marine protected areas (MPAs) are often promoted as tools for biodiversity conservation as well as for fisheries management. Despite increasing evidence of their usefulness, questions remain regarding the optimal design of MPAs, in particular concerning their function as fisheries management tools, for which empirical studies are still lacking. Using 28 data sets from seven MPAs in Southern Europe, we developed a meta‐analytical approach to investigate the effects of protection on adjacent fisheries and asking how these effects are influenced by MPA size and age. Southern European MPAs showed clear effects on the surrounding fisheries, on the ‘catch per unit effort’ (CPUE) of target species, but especially on the CPUE of the marketable catch. These effects depended on the time of protection and on the size of the no‐take area. CPUE of both target species and the marketable catch increased gradually by 2–4% per year over a long time period (at least 30 years). The influence of the size of the no‐take area appeared to be more complex. The catch rates of the entire fishery in and around the MPA were higher when the no‐take areas were smaller. Conversely, catch rates of selected fisheries that were expected to benefit most from protection increased when the no‐take area was larger. Our results emphasize the importance of MPA size on its export functions and suggest that an adequate, often extended, time frame be used for the management and the evaluation of effectiveness of MPAs.     

Insights into an undescribed high-elevation lake (6,170 m a.s.l.) on Volcán Llullaillaco: A physical and microbiological view

1. High elevation lakes are extreme ecosystems and serve as sentinels of various global changes.
2. An expedition to Volcán Llullaillaco in 1996 discovered an unstudied high-elevation lake (6,170 m a.s.l.) that probably was formed as a result of the past eruptive events or climatic processes such as glacial retreat in the lake basin.
3. This article describes an initial physical characterization of the lake and its microbial communities derived from two sampling expeditions in 2013 and 2016.
4. The microbial community in the lake, with an area between 1.2 and 1.4 ha and a depth of 6.8 m, was dominated by Proteobacteria, Actinobacteria and Haloarchaea. In addition, 26 bacterial isolates were identified within the genera Subtercola, Xylophilus, Rhodanobacter, Mesorhizobium and Pseudomonas.
5. Lago Llullaillaco is one of the highest recorded lakes in the world, and this study highlights the unique microbial diversity of this aquatic ecosystem and the importance of its preservation to understand the complex biological processes under polyextreme conditions.

     

Evaluation of Three In Vitro Enzyme Assays for Estimating Protein Digestibility in the Pacific White Shrimp Penaeus vannamei1

Abstract— In vitro enzyme assays are rapid, inexpensive techniques for estimating protein digestibility of feed ingredients. Three assays—the Lazo single-enzyme assay with porcine trypsin; the Hsu multi-enzyme assay with porcine trypsin, α-chymotrypsin, and peptidase; and the Satterlee multi-enzyme assay with porcine trypsin, α-chymotrypsin, peptidase, and bacterial protease—were used to estimate relative protein digestibility (RPD) of selected feed ingredients used in diets for the Pacific white shrimp Penaeus vannamei. Ingredients tested were casein, gelatin, rice bran, shrimp meal, soybean meal, wheat gluten, and six varieties of fish meal. A highly significant, inverse, linear relationship existed between final pH in each of the enzyme assays and in vivo apparent protein digestibility of the ingredient in P. vannamei feeding trials. Ranking of RPD coefficients obtained in the Lazo single-enzyme assay followed closely the ranking of published in vivo apparent protein digestibility coefficients for the same ingredients in P. vannamei digestibility trials. Results indicated that a single-enzyme assay with porcine trypsin identified differences in protein digestibility of feedstuffs in vitro as well as the two multi-enzyme assays tested. The porcine-trypsin, single-enzyme assay appears to be a potentially useful tool for evaluating protein quality and relative protein digestibility of feedstuffs for P. vannamei.     

Growth and feeding of Patagonian pejerrey Odontesthes hatcheri reared in net cages

An experiment was performed to evaluate the performance of Patagonian pejerrey during net cage rearing in the oligomesotrophic reservoir Exequiel Ramos Mexía. Survival, growth, nutrition and reproduction were evaluated for two lots of pejerrey, initial weights 4.0 and 2.5 g, reared in net cages for 22 and 14 months respectively. Fish were stocked at 29 and 48 individuals m^?3 densities and fed with an experimental pejerrey feed. During the experiment, temperature fluctuated between 6.6 and 19.6 °C. The two lots did not show substantial differences in survival (pooled survival at the end of the experiment >80%) and the thermal‐unit growth coefficient (TGC), daily feed intake and feeding efficiency were 0.43±0.19, 1.70±0.80 and 53.6±9.9 respectively. Digestive tract analysis showed that caged pejerrey can consume substantial quantities of natural food, taking advantage of its planktivorous condition. Pejerrey showed high percentage survival, slow growth and early sexual maturation in captivity. The use of the TGC is proposed as a model for describing the growth pattern of this species and other pejerrey under culture conditions.     

Cryopreservation effects on the sperm quality of cachama blanca Piaractus brachypomus (Cuvier 1818)

The effects of straws volume, cryoprotectants and thawing temperatures were evaluated on the sperm quality of cachama blanca Piaractus brachypomus (Cuvier), an important Colombian fish species. Sexually mature fish were induced to ovulation or spermiation with a carp pituitary extract. A pool of suitable sperm samples was diluted in glucose, egg yolk, dimethyl sulphoxide (DMSO‐10%), methanol (MET‐10%) or ethylene glycol (ETG‐5%) and packed in 0.5, 2.5 or 5.0 mL straws and frozen in nitrogen vapour. The thawing process was performed in a 35 or an 80 °C water bath. The fertility was evaluated after 6 h post fertilization. The highest motility percentage (33 ± 3%) was observed with sperm cryopreserved with DMSO, packed in 5 mL straws and thawed at 35 °C. The treatments with DMSO and MET packed in 0.5 and 5.0 mL straws and thawed at 35 °C showed the highest fertility (higher than 71%) and the lowest fertility was obtained with MET‐2.5 mL (9 ± 5%). In all the treatments, a significant decrease in the sperm quality was observed at 80 °C. Sperm cryopreserved with DMSO‐10% or MET‐10%, packed in 2.5 or 5.0 mL straws are suitable to achieve acceptable fertilization and to fertilize high amounts of eggs.