Pollution characteristics of mercury (Hg) in surface sediments of major basins,China

To investigate the pollution status and potential pollution risk of mercury (Hg) in China, surface sediment samples were collected from eight hundred and eighty-one sites, including ten major basins (Songhua River Basin (SRB), Liao River Basin (LRB), Hai River Basin (HRB), Yellow River Basin (YRB), Huai River Basin (HuRB), Yangtze River Basin (YtRB), Pearl River Basin (PRB), Southeastern River Basin (SeRB), Southwestern River Basin (SwRB) and Northwestern River Basin (NwRB)). Results showed that Hg concentrations in sediments of ten basins in China ranged from 0.001 to 8.800 mg/kg, with average ± S.D. value of 0.274 ± 0.675 mg/kg, which was obviously higher than Chinese soil background value (0.038 mg/kg) and Chinese sediment background value (0.040 mg/kg). The mean Hg concentration of ten basins decreased in the order of HRB > YtRB > SRB > PRB > HuRB > SwRB > YRB > SeRB > LRB > NwRB. Moreover, it was found that the Hg concentrations in the sediments of LRB, YtRB, PRB, SeRB and SwRB were partly driven by their total organic carbon (TOC) contents, while the effect of pH on the distribution of Hg was not obvious. The Hg concentration data were also compared with those got in other periods (1994–2015) to obtain the general variation tendency of Hg level. It was recorded that Hg concentrations in HRB have remained on high levels for a long history, while Hg contamination situation in YRB after 2004 has potentially turned to be better. The results of pollution assessment by sediment quality assessment guidelines (SQGs), contamination factor (CF), geoaccumulation index (I_geo) and potential ecological risk (E_i) suggested that YRB and HRB were the most seriously polluted river basins among the ten basins. It is urgent of constructing SQGs in China to scientifically evaluate the Hg pollution in the future.     

常春二乔玉兰春夏季开花节律及营养效应研究

为系统掌握常春二乔玉兰春夏季开花物候节律,探讨其与营养物质的关系,本研究以6年生常春二乔玉兰为试验材料,观测其年生长发育节律、春夏季开花物候特性以及茎段营养物质的含量变化。结果表明：（1）每年12月始至翌年2月下旬为常春二乔玉兰休眠期。2月下旬花芽膨大生长,并于3月开始春季开花,花期持续约20 d。4月进行营养生长,5月完成花芽分化。5月底部分花芽膨大并于6月开始开花,夏季花期持续约20 d。7~9月为未膨大花芽的发育滞缓期。此外,少量夏季开放的花的基部侧芽再次分化形成花芽。10~12月随着落叶的开始,树体逐渐进入休眠期。（2）常春二乔玉兰营养生长后分化的花芽能够花开两季。春季开花为先花后叶,开花率为100%,开花同步率较高,雌、雄蕊发育正常,为可育花。夏季开花为花叶同放,开花率约为30%,且开花同步率较低,开放的花内雌、雄蕊发育异常,为不育花。（3）春季开花期间可溶性糖和可溶性蛋白呈下降趋势,淀粉含量于开花后期下降;夏季开花期间可溶性糖和淀粉总体呈先降后升趋势,而可溶性蛋白总体呈下降趋势。综上所述,常春二乔玉兰春、夏季开花期内开花模式存在一定差异,其显著节律特征与营养物质含量变化有关,推测低水平的可溶性糖及高水平的淀粉和可溶性蛋白有利于春季开花的启动,而低水平的可溶性蛋白及高水平的可溶性糖和淀粉含量则有利于夏季开花的实现。     

Meta-analysis of spineless cactus feeding to meat lambs: performance and development of mathematical models to predict dry matter intake and average daily gain

Spineless cactus is a useful feed for various animal species in arid and semiarid regions due to its adaptability to dry and harsh soil, high efficiency of water use and carbohydrates storage. This meta-analysis was carried out to assess the effect of spineless cactus on animal performance, and develop and evaluate equations to predict dry matter intake (DMI) and average daily gain (ADG) in meat lambs. Equations for predicting DMI and ADG as a function of animal and diet characteristics were developed using data from eight experiments. The dataset was comprised of 40 treatment means from 289 meat lambs, in which cactus was included from 0 to 75% of the diet dry matter (DM). Accuracy and precision were evaluated by cross-validation using the mean square error of prediction (MSEP), which was decomposed into mean bias, systematic bias and random error; concordance correlation coefficient, which was decomposed into accuracy (C_b) and precision (ρ); and coefficient of determination (R²). In addition, the data set was used to evaluate the predicting accuracy and precision of the main lamb feeding systems (Agricultural and Food Research Council, Small Ruminant Nutritional System, National Research Council and Institut National de la Recherche Agronomique) and also two Brazilian studies. The DMI, CP intake (CPI), metabolizable energy (ME) intake and ADG increased when cactus was included up to 499 g/kg DM (P<0.001). In contrast, animals fed high levels of cactus (>500 g/kg DM) had a decreased DMI, CPI and NDF intake, but increased feed efficiency (P<0.001) and similar ADG compared with those without cactus addition. The DMI was positively correlated with initial BW, final BW, concentrate and ADG, while it was negatively correlated with cactus inclusion and ME of the diet. On other hand, ADG was positively correlated with DMI, initial and mean BW and concentrate, and it was negatively correlated with cactus inclusion. The two developed equations had high accuracy (C_b of 0.95 for DMI and 0.94 for ADG) and the random error of MSEP was 99% for both equations. The precision of both equations was moderate, with R² values of 0.53 and 0.50 and ρ values of 0.73 and 0.71 for DMI and ADG, respectively. In conclusion, the developed equation to predict DMI had moderate precision and high accuracy, nonetheless, it was more efficient than those reported in the literature. The proposed equations can be a useful alternative to estimate intake and performance of lambs fed cactus.     

Habitat distribution modelling and reinforcement of Elaeocarpus serratus L. - A threatened tree species of Assam,India for improvement of its conservation status

Elaeocarpus serratus L., commonly known as ‘rudraksh’ referred in the Ayurveda as a wonderful plant for strengthening body constitutions, has been recognized as a threatened plant of Assam, India. Traditionally, rudraksh beads, its bark and leaves are used to cure various ailments like stress, anxiety, depression, nerve pain, epilepsy, migraine, lack of concentration, asthma, hypertension, arthritis and liver diseases. The population stock of the species has been depleting very fast in its natural habitat due to rapid habitat fragmentation and changing climate altering the structural and functional integrity of the plant. Hence, conservation of E. serratus L. with proper scientific investigation to prevent from extinction in its wild habitat is urgently needed. The present study was emphasized with the specific objectives to study the distribution and population status, predication of suitable sites through ENM, standardization of macropropagation methods and reinforcement/reintroduction into the suitable wild habitat to improve conservation status. In the present investigation E. serratus L. was reported in few locations of Assam and Arunachal Pradesh with population sizes of mean density, frequency of occurrence and abundance in relation to other associated species as 0.333, 13.922 and 2.215 respectively. For improving the conservation status, potential area and habitat for reinforcement was predicted using Maximum Entropy (MaxEnt) distribution modelling algorithm. Subsequently, macropropagation protocol was standardized through seed germination and air-layering; saplings were raised and 1050 saplings were reintroduced to the wild habitats selected on the basis of ecological niche modelling. Survival rate was found significantly high as 68%, suggesting that our approach is effective for changing population status and to conserve the plant.     

An Acinetobacter baumannii,Zinc-Regulated Peptidase Maintains Cell Wall Integrity during Immune-Mediated Nutrient Sequestration

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Functional amino acid supplementation postweaning mitigates the response of normal birth weight more than for low birth weight pigs to a subsequent Salmonella challenge

Previous work has shown that dietary supplementation with key functional amino acids (FAA) improves growth performance and immune status of disease-challenged normal birth weight (NBW) pigs. It is not known whether FAA supplementation attenuates the effects of a subsequent disease challenge or whether this response is similar in low birth weight (LBW) pigs. The objective was to determine the effects of birth weight and FAA supplementation during the postweaning period in Salmonella-challenged pigs. Thirty-two LBW (1.08 ± 0.11 kg) and NBW (1.58 ± 0.11 kg) pigs were assigned to a nursery feeding program at weaning (25 d) for 31 days in a 2 × 2 factorial arrangement. Factors were birth weight category (LBW vs. NBW) and basal (FAA–) or supplemented FAA profile (FAA+; Thr, Met, and Trp at 120% of requirements). At d 31, pigs were placed onto a common grower diet and, after a 7-d adaptation period, were inoculated with Salmonella Typhimurium (ST; 2.2 × 10⁹ colony-forming units/mL) and monitored for 7-d postinoculation. Growth performance, rectal temperature, fecal score, indicators of gut health, ST shedding score in feces, intestinal ST colonization and translocation, and blood parameters of acute-phase response and antioxidant balance were measured pre- and postinoculation. Inoculation with ST increased temperature and fecal score, and the overall rectal temperature was higher in LBW compared to NBW pigs (P < 0.05). Postinoculation (d 7), reduced:oxidized glutathione was increased in NBW compared to LBW pigs (P < 0.05). Salmonella shedding and translocation to spleen were lower in NBW-FAA+ compared to NBW-FAA? pigs (P < 0.05). Postinoculation average daily gain was higher in NBW-FAA+ (P < 0.05) compared to the other groups. Postinoculation haptoglobin, superoxide dismutase, and colonic myeloperoxidase were increased in LBW-FAA? pigs (P < 0.05). Ileal alkaline phosphatase was decreased in LBW compared to NBW (P < 0.05). Overall, FAA supplementation represents a potential strategy to mitigate the effect of enteric disease challenge in NBW, but not LBW pigs.     

黑木耳子实体粉代替部分膳食对高脂模型小鼠营养性肥胖预防作用

本文旨在研究黑木耳粉代替部分膳食对模型小鼠预防营养性肥胖的作用功效。试验选择5周龄健康ICR雄性小鼠48只,随机分为正常对照组(CK)、高脂组(HFD)、阳性药物对照组(PD)和黑木耳粉添加组(AH)。连续饲喂9周,检测小鼠的各项生理生化指标。结果表明：与HFD组相比,AH组小鼠体重、附睾脂肪指数显著降低(P<0.05);Lee’s指数、血清葡萄糖(GLU)含量、甘油三酯(TG)含量和肝脏指数含量极显著降低(P<0.01),血清高密度脂蛋白胆固醇(HDL-C)和肝脏HDL-C含量极显著提高(P<0.01);染色结果观察到AH组小鼠肝脏中脂肪细胞减小,脂质含量降低;附睾脂肪体积减小,附睾细胞形状较规则。高通量测序分析发现,黑木耳粉干预有效改善了小鼠肠道中的变形菌门、螺杆菌属与拟杆菌属的相对丰度。研究结果表明黑木耳有显著预防小鼠营养性肥胖的功效,为黑木耳的开发利用提供依据。     

Food and specific macronutrient limitation in an assemblage of predatory beetles

Habitats vary in food resources with carnivores often being prey limited, but it is unclear whether habitats facilitate a nutritionally balanced diet. Two paradigms in nutritional ecology, ecological stoichiometry and nutritional geometry, predict that carnivores are limited mainly by protein or lipid, respectively. Using the carabid beetle Anchomenus dorsalis and 10 other predatory beetles from agricultural fields, we developed and tested two simple procedures for quantifying macronutrient‐specific habitat conditions without requiring information about the natural prey. Both procedures assume that predators forage for nutrients rather than specific prey. Our results show that 10 of 11 species were food limited. Five species were lipid limited and one species was protein limited in the field. Co‐existing predator species showed considerable segregation of fundamental macronutritional niches. A linear relationship between specific nutrient limitation and the target lipid:protein (L:P) intake ratio indicates that species with high L:P target are more protein limited while species with low L:P target are more lipid limited. The study illustrates how species within a natural assemblage vary in nutritional niche and in specific nutrient limitation.