No apparent differences in intestinal histology of channel catfish (Ictalurus punctatus) fed heat-treated and non-heat-treated raw soybean meal

The histopathologic effects of feeding heat‐treated soybean meal to fingerling channel catfish (Ictalurus punctatus) were studied. Fish were fed one of six diets: a diet containing 450 g kg^?1 commercial soybean meal (CSBM), or diets with the CSBM replaced by non‐heat‐treated raw soybean meal (RSBM0), or RSBM heated at 130 °C for 5 min (RSBM5), 10 min (RSBM10), 20 min (RSBM20) or 40 min (RSBM40). After 10 weeks, tissue samples were taken from the stomach, proximal intestine, distal intestine, liver, pancreas and spleen from fish in each group for histologic examination. Mild necrotic lesions were found in the gastric glands, pancreas and liver of fish in all the groups (treatment and control groups). Hepatic glycogen deposition was also observed in all the groups, and the spleen samples exhibited considerable brownish‐black pigment deposition around the splenic corpuscles and diffuse mild‐to‐moderate congestion in all of the groups. Generally, these histologic effects appeared to be equivocal between all of the groups, and no abnormalities were noted in the proximal or distal intestine. These findings suggest that feeding channel catfish a diet containing 450 g kg^?1 non‐heat‐treated RSBM did not cause severe histologic changes associated with soybean meal anti‐nutritional factors as have been reported in salmonids.     

重刚比对悬索静态位形影响的建模与分析

为探究悬索的自重、刚度及分布荷载对悬索的静态平衡位形的影响,通过悬索状态分类与悬索单元的受力分析与数学模型,引入无量纲参数,分析了悬索在自然态、无荷自重作用状态与有分布荷载作用状态下的基本静态性能。建立了考虑自重和分布荷载同时作用下的悬索静态张力与悬索单位长度重刚比、挠度及支座间距的数学模型。研究表明:当重刚比小到一定程度时(β≤10-2),悬索的静态位形基本重合,此时悬索的刚度对静态位形起主导作用,悬索的静态位形可以看成不可伸长的悬索进行处理;重刚比很大时(β≥10-1),悬索的自重与分布载荷对静态位形起主导作用,悬索自重与分布荷载越大,悬索的中央挠度也越大。重刚比小的悬索在接近原长跨距时,最大张力与水平张力会明显增大,但重刚比大的悬索增加的幅度不明显,说明重刚比大的悬索因为弹性模量小,主要产生了弹性变形,因此不能盲目拉紧悬索。最后利用挂重法对悬索的静态位形参数进行了实验验证,实验结果与理论结果的相对误差均在4.95%以内,说明了模型的可行性并达到了工程应用相对误差不超过5%的精度要求。     

Tryptophan- and indole-excreting bacterial mutants

Prototrophic mutants of Escherichia coli capable of producing indole and tryptophan were obtained by selecting for resistance to antimetabolites. An anthranilic acid auxotroph grown under conditions which would derepress the tryptophan synthetase system would also accumulate substantial quantities of L-tryptophan.     

The Internal Transfer of Nutrients in a Scots Pine Stand 2. The Patterns of Transfer and the Effects of Nitrogen Availability

The fall of fine litter was 4.5 tonnes ha^–1 y^–1,(78% needles) returning to the ground 36.6 kg N, 2.2 kg P, 7.6kg K, 12.1 kg Ca and 2.0 kg Mg. Nutrient input in rainfall (880mm in 1978) was 2.6 kg N, 0.4 kg P, 4.3 kg K, 7.6 kg Ca and1.4 kg Mg. Throughfall was 534 mm. The method of Miller, Cooperand Miller (1976) was used to estimate aerosol contributions,leaching and absorption. Retranslocation estimates were 59.6kg N ha^–1 y^–1 (55% of Requirement), 8.5 kg P (64%R), 42.0 kg K (56% R) and 1.2 kg Mg (14% R). Retranslocationwas unchanged, but uptake increased with added N % P and decreasedwith added sawdust and glucose. Other typical effects of nutrientamendment were observed: with added N % P growth increased,current tissues had higher concentrations of N and P and litterfalldecreased in the first year but was heavier in the second year:with added sawdust and glucose, growth declined but concentrationsof N and P remained substantially the same.     

The effect of powdery mildew (Erysiphe graminis f. sp. hordei) and leaf rust (Puccinia hordei) on spring barley in New Zealand. II. Apical development and yield potential

Reduced yields caused by powdery mildew and leaf rust in two seasons were associated with reduced plant growth. Combinations of early, late and full epidemics in one season, and 12 epidemic combinations in the second, were designed to identify crop sensitivity to disease by comparing growth and development with healthy plants. Early epidemics reduced ear number by increasing tiller death, and reduced grain number by effects on spikelet, floret or grain abortion, depending on the type of epidemic. Epidemics later in crop growth increased floret and grain abortion and also reduced grain weight.
There was no compensation by later-determined components for reduced growth and delayed development at earlier growth stages. Plants infected at early growth stages were more sensitive to late infections, seen as effects on the later-determined components, than plants which were healthy initially. Interactions occurred between epidemics at different times and are likely to occur between diseases and other constraints.     

Bats and their vital ecosystem services: a global review

Bats play crucial ecosystem services as seed dispersers, pollinators, controllers of insects, and nutrient recyclers. However, there has not been a thorough global review evaluating these roles in bats across all biogeographical regions of the world. We reviewed the literature published during the last two decades and identified 283 relevant studies: 78 dealt with the control of potential insect pests by bats, 80 related to the suppression of other arthropods, 60 on the dispersal of native or endemic seeds, 11 dealt with the dispersal of seeds of introduced plants, 29 on the pollination of native or endemic plants, 1 study on pollination of introduced plants, and 24 on the use of guano as fertilizer. Our literature search showed that queries combining the terms “seed dispersal,” “insectivorous bats,” “nectarivorous bats,” “use of guano,” and “ecosystem services” returned 577 studies, but half were experimental in nature. We found that the evaluation of ecosystem services by bats has been mostly conducted in the Neotropical and Palearctic regions. To detect differences across relevant studies, and to explain trends in the study of ecosystem services provided by bats, we performed generalized linear mixed models (GLMM) fitted with a Poisson distribution to analyze potential differences among sampling methods. We identified 409 bat species that provide ecosystem services, 752 insect species consumed by bats and 549 plant species either dispersed or pollinated by bats. Our review summarizes the importance of conserving bat populations and the ecological services they provide, which is especially important during the current pandemic.     

Identifying Potential Antioxidant Properties from the Viscera of Sea Snails (Turbo cornutus)

Turbo cornutus, the horned turban sea snail, is found along the intertidal and basaltic shorelines of Jeju Island, Korea. T. cornutus feeds on seaweeds (e.g., Undaria sp., and Ecklonia sp.) composed of diverse antioxidants. This study identified potential antioxidant properties from T. cornutus viscera tissues. Diverse extracts were evaluated for their hydrogen peroxide (H₂O₂) scavenging activities. T. cornutus viscera protamex-assisted extracts (TVP) were purified by gel filtration chromatography (GFC), and potential antioxidant properties were analyzed for their amino acid sequences and its peroxidase inhibition effects by in silico molecular docking and in vitro analysis. According to the results, T. cornutus viscera tissues are composed of many protein contents with each over 50%. Among the extracts, TVP possessed the highest H₂O₂ scavenging activity. In addition, TVP-GFC-3 significantly decreased intracellular reactive oxygen species (ROS) levels and increased cell viability in H₂O₂-treated HepG2 cells without cytotoxicity. TVP-GFC-3 comprises nine low molecular bioactive peptides (ELR, VGPQ, TDY, ALPHA, PAH, VDY, WSDK, VFSP, and FAPQY). Notably, the peptides dock to the active site of the myeloperoxidase (MPO), especially TDY and FAPQY showed the MPO inhibition effects with IC₅₀ values of 646.0 ± 45.0 µM and 57.1 ± 17.7 µM, respectively. Altogether, our findings demonstrated that T. cornutus viscera have potential antioxidant properties that can be used as high value-added ingredients.