Effect of volatile compounds in grass silage on voluntary intake by growing cattle

Twenty-four low dry matter (DM) silages differing in fermentation quality were harvested at the same time from a crop that consisted mainly of timothy (Phleum pratense), and meadow fescue (Festuca pratensis). The silage samples were analysed by gas chromatography (GC) - mass spectrometry and gas chromatography - flame ionisation detection in order to determine and quantify volatiles present in silage. The voluntary intake of the 24 silages had been measured in a previous feeding trial with growing steers of Norwegian Red. Thirteen esters, five aldehydes, three alcohols, and one sulphide were identified and quantified. A total of 51 variables describing the chemical composition of the silages were included in a partial least-squares regression, and the relationship of silage fermentation quality to voluntary intake was elucidated. The importance of variables describing silage fermentation quality in relation to intake was judged from a best combination procedure, jack-knifing, and empirical correlations of the variables to intake. The GC-analysed compounds were mainly present in poorly fermented silages. However, compared with other explanatory chemical variables none of these compounds was of importance for the voluntary intake as evaluated by partial least-squares regression. A validated variance of 71% in silage DM intake was explained with the selected variables: total acids (TA), total volatile fatty acids (TVFA), lactic acid/total acid ratio and propionic acid. In this study extent (by the variable TA) and type of silage fermentation (by TVFA) influenced intake. Further, it is suggested that by restricting the fermentation in low DM grass silages the potential intake of silage DM is maximised.     

TGFβ Signaling in Myeloid Cells Regulates Mammary Carcinoma Cell Invasion through Fibroblast Interactions

Metastasis is the most devastating aspect of cancer, however we know very little about the mechanisms of local invasion, the earliest step of metastasis. During tumor growth CD11b⁺Gr1⁺ cells, known also as MDSCs, have been shown to promote tumor progression by a wide spectrum of effects that suppress the anti-tumor immune response. In addition to immunosuppression, CD11b⁺Gr1⁺ cells promote metastasis by mechanisms that are currently unknown. CD11b⁺Gr1⁺ cells localize near fibroblasts, which remodel the ECM and leave tracks for collective cell migration of carcinoma cells. In this study we discovered that CD11b⁺Gr1⁺ cells promote invasion of mammary carcinoma cells by increasing fibroblast migration. This effect was directed by secreted factors derived from CD11b⁺Gr1⁺ cells. We have identified several CD11b⁺Gr1⁺ cell secreted proteins that activate fibroblast migration, including CXCL11, CXCL15, FGF2, IGF-I, IL1Ra, Resistin, and Shh. The combination of CXCL11 and FGF2 had the strongest effect on fibroblast migration that is associated with Akt1 and ERK1/2 phosphorylation. Analysis of subsets of CD11b⁺Gr1⁺ cells identified that CD11b⁺Ly6C^highLy6G^low cells increase fibroblast migration more than other myeloid cell populations. Additionally, tumor-derived CD11b⁺Gr1⁺ cells promote fibroblast migration more than splenic CD11b⁺Gr1⁺ cells of tumor-bearing mice. While TGFβ signaling in fibroblasts does not regulate their migration toward CD11b⁺Gr1⁺ cells, however deletion of TGFβ receptor II on CD11b⁺Gr1⁺ cells downregulates CXCL11, Shh, IGF1 and FGF2 resulting in reduced fibroblast migration. These studies show that TGFβ signaling in CD11b⁺Gr1⁺ cells promotes fibroblast directed carcinoma invasion and suggests that perivascular CD11b⁺Ly6C^highLy6G^low cells may be the stimulus for localized invasion leading to metastasis.     

甘肃盐池湾黑颈鹤亚成体夏季生境选择

开展对亚成体的研究,可以更加全面了解一个物种,进而更有效地开展保护工作。甘肃盐池湾国家级自然保护区是黑颈鹤（Grus nigricollis）成体的重要繁殖地和亚成体的重要栖息地之一。为研究甘肃盐池湾黑颈鹤亚成体生境选择,于2020年7月初至8月中旬在盐池湾党河湿地展开调查,并依据Johnson对生境选择空间尺度的划分,对亚成体活动区内各类型生境和觅食微生境的生境选择进行了研究。通过遥感影像解译和卫星跟踪分别获得各栖息地类型面积以及黑颈鹤的活动位点,利用核密度分析法估计活动区面积并利用Manly研究中的设计Ⅲ来研究活动区内各类型生境选择;通过选取利用样方和对照样方,使用χ2检验、独立样本t检验和Mann-Whitney U检验,对比检验样方数据,进行微生境选择的研究。结果表明,活动区内各类型生境中亚成体选择河流,拒绝戈壁和沼泽化草甸,对沼泽既不选择也不拒绝,而成体选择湖泊,没有利用河流,同时拒绝戈壁、山脉、沼泽化草甸和盐化草甸,对沼泽既不选择也不拒绝;觅食微生境选择中,亚成体选择平均植被盖度为57.07% ± 4.53%,基质类型为泥炭,基质硬度为中,主要植被黑褐苔草（Carex atrofusca）的微生境栖息,相比成体,亚成体选择的生境基质更硬,距道路距离更近,距房屋、河流、山脉和湖泊距离更远。亚成体的栖息地选择主要受到生境质量、生境资源有限性以及成体选择等因素的影响。在这些因素的影响下,亚成体与成体产生了生态位分离,并在栖息地选择上出现了分化。这种分化对亚成体的生存和成体的繁殖都有益,可以避免种内无效的冲突和竞争,有利于亚成体和成体的适合度增加。保护黑颈鹤的栖息环境需同时考虑到亚成体的选择和生存。     

Local and systemic effects of two herbivores with different feeding mechanisms on primary metabolism of cotton leaves

Caterpillars and spider mites are herbivores with different feeding mechanisms. Spider mites feed on the cell content via stylets, while caterpillars, as chewing herbivores, remove larger amounts of photosynthetically active tissue. We investigated local and systemic effects of short-term caterpillar and spider mite herbivory on cotton in terms of primary metabolism and growth processes. After short-term caterpillar feeding, leaf growth and water content were decreased in damaged leaves. The glutamate/glutamine ratio increased and other free amino acids were also affected. In contrast, mild spider mite infestation did not affect leaf growth or amino acid composition, but led to an increase in total nitrogen and sucrose concentrations. Both herbivores induced locally increased dark respiration, suggesting an increased mobilization of storage compounds potentially available for synthesis of defensive substances, but did not affect assimilation and transpiration. Systemically induced leaves were not significantly affected by the treatments performed in this study. The results show that cotton plants do not compensate the loss of photosynthetic tissue with higher photosynthetic efficiency of the remaining tissue. However, early plant responses to different herbivores leave their signature in primary metabolism, affecting leaf growth. Changes in amino acid concentrations, total nitrogen and sucrose content may affect subsequent herbivore performance.     

Self-monitoring of blood glucose in patients with diabetes who do not use insulin-are guidelines evidence-based?

Diabet. Med. 29, 1226-1236 (2012) ABSTRACT: Aims To evaluate if clinical practice guideline recommendations regarding self-monitoring of blood glucose in patients with diabetes not using insulin follow the principles of evidence-based medicine. Methods After a search from 1999 to 2011, 18 clinical practice guidelines were included. Recommendations regarding self-monitoring of blood glucose were graded on a scale from one (strongly against self-monitoring) to four (strongly in favour of self-monitoring) and compared with the similarly graded conclusions of systematic reviews that were cited by the clinical practice guidelines. We also investigated how clinical practice guideline characteristics, for example funding sources, and quality of references cited could be related to the guideline recommendations. Results The clinical practice guidelines cited in total 15 systematic reviews, 14 randomized controlled trials, 33 non-randomized controlled trials papers and 18 clinical practice guidelines or position statements. The clinical practice guideline recommendations had an average grade of 3.4 (range 2.0-4.0). Higher grades were seen for clinical practice guidelines that acknowledged industry funding (mean value 4.0) or were issued by organizations depending on private funding (mean value 3.6 vs. 3.0 for governmental funding). The conclusions of the 15 systematic reviews had a mean grade of 2.2 (range 1.0-3.8). Systematic reviews with low grades were less cited. In total, 21 randomized controlled trials were included in the systematic reviews. Approximately half of these evaluated an educational intervention where the effect of self-monitoring of blood glucose could not be clearly isolated. Conclusions Clinical practice guidelines were more in favour of self-monitoring use than the systematic reviews that were cited. The citation practice was non-systematic and industry funding seemingly led to a more positive attitude towards use of self-monitoring of blood glucose.     

Effect of phospholipase C (Bacillus cereus) on freshly isolated and 4-day-stored human platelets.

Phospholipase C (from Bacillus cereus) was used to study fresh and stored human platelets. Provided that the enzyme was inactivated before lipid extraction, no significant degradation of phospholipid in fresh cells was noted, even when platelets were activated or induced to change shape by ADP, collagen or thrombin. With platelets isolated from concentrates stored for transfusion for 4 days at 22 degrees C, membrane phospholipids were degraded by the enzyme to an extent depending on the pH in the platelet concentrate at day 4 of storage. The extent of phospholipid hydrolysis in platelets correlated well with the extent of release of lactate dehydrogenase during storage, with both being minimal for platelets from concentrates of final pH 6.5-6.9. Under non-lytic conditions, phosphatidylcholine was the phospholipid most degraded (40%), with no significant degradation of phosphatidylserine being detected. Storage does not seem to alter the distribution of phospholipids at the external leaflet of the plasma membrane.     

添加玉米和水稻秸秆对淹水土壤pH、二氧化碳及交换态铵的影响

通过温室土壤培养试验,研究了不同添加量玉米和水稻秸秆对淹水土壤pH、CO₂及交换态铵的影响.结果表明：在接近中性的土壤中加入秸秆可使土壤pH值降低,4 g·kg^-1玉米和水稻秸秆处理的土壤pH值均与对照差异显著（P＜0.05）,而1 g·kg^-1玉米和水稻秸秆处理与对照差异不显著（P＞0.05）.土壤溶液中的CO₂含量随秸秆添加量的增加而增大,1 g·kg^-1玉米和水稻秸秆处理的土壤溶液CO₂含量最大值分别为35.9％和31.9％（v/v）,与对照（25.8％）差异达显著水平（P＜0.05）,但两者间差异不显著（P＞0.05）;4 g·kg^-1玉米和水稻秸秆处理的土壤溶液CO₂含量最大值分别为54.2％和41.8％（v/v）,与对照差异极显著（P＜0.01）,两者间差异也达显著水平（P＜0.05）.在不施氮肥的情况下,添加秸秆可降低土壤铵态氮浓度,且铵态氮浓度随秸秆添加量的增加而降低,不同添加量处理间差异显著（P＜0.05）;在施入氮肥的情况下,1 g·kg^-1玉米和水稻秸秆处理提高了土壤铵态氮浓度,而4 g·kg^-1玉米和水稻秸秆处理降低了土壤铵态氮浓度.无论是否施入氮肥,玉米和水稻秸秆处理的土壤铵态氮浓度差异不显著（P＞0.05）.