红富士苹果品质与生态气象因子关系的研究

通过对我国不同生态类型区红富士苹果果实品质的调查和实验室分析,应用多元统计分析,研究了不同生态类型区红富士果实品质差异及影响果实品质的主要气象因子．红富士苹果在我国陕西渭北、甘肃陇东和山东渤海湾地区呈现出果实大、果面光洁、果色鲜艳的特征;而在西南高地果色暗红;黄河故道地区果面粗糙、着色差、果肉松;宁夏地区果实偏小．经典范相关分析筛选出影响苹果品质因素的主要气象因子,不同品质因素受气象因子的影响各异,果实花青素含量主要受年总降雨量、１０月平均温度、７月平均最高气温、９月平均最低气温、９月日照时数等气象因子的影响     

Compensatory growth feeding strategy does not overcome negative effects on growth and carcass composition of low birth weight pigs

The aim of this study was to evaluate whether the compensatory growth feeding strategy could be a suitable solution for overcoming the negative effects on growth, carcass composition and meat quality of low birth weight pigs. Forty-two Swiss Large White barrows from 21 litters were selected at weaning and categorized into either being light (L; >0.8 and <1.3 kg) or heavy (H; >1.7 kg) birth weight pigs. From 27.8 kg BW, pigs were assigned within birth weight group to one of three feeding groups: AA: ad libitum access to the grower and finisher diet, RR: restricted access to the grower and finisher diet or RA: restricted access to the grower diet and ad libitum access to the finisher diet. At slaughter, the longissimus (LM) and semitendinosus (STM) muscles were removed from the right side of the carcass. Weight, girth and length of the STM and the LM area were determined after muscle excision. Carcass characteristics and meat quality traits were assessed. Using mATPase histochemistry, myofibre size and myofibre type distribution were determined in the LM and STM. Because of longer days on feed, total feed intake was greater (P<0.01) and feed efficiency was lower (P<0.01) in L than H barrows. Regardless of the birth weight group, AA and RA barrows grew faster (P<0.05) than RR barrows. During the compensatory growth period, RA barrows grew faster (P<0.05) than AA or RR barrows. Growth efficiency did not differ between RA and RR barrows but was greater (P<0.05) compared with AA barrows. Carcasses of L barrows were fatter as indicated by the lower (P⩽≤0.05) lean meat and greater (P⩽0.02) omental and subcutaneous fat percentage. Lean meat percentage was lower (P⩽0.05) in AA and RA than RR barrows. These differences caused by ad libitum feed access tended to be greater (feeding regime × birth weight group interaction; P<0.08) in L than H barrows. In L barrows, slow oxidative, fast oxidative glycolytic and overall average myofibre size of the LM and the fast glycolytic myofibres and overall average myofibre size of the dark portion of the STM were larger (P⩽0.03) than in H barrows. The study revealed that the compensatory growth feeding strategy was inadequate in overcoming the disadvantages of low birth weight.     

Conformation of the HIV-1 Gag protein in solution

A single multi-domain viral protein, termed Gag, is sufficient for assembly of retrovirus-like particles in mammalian cells. We have purified the human immunodeficiency virus type 1 (HIV-1) Gag protein (lacking myristate at its N terminus and the p6 domain at its C terminus) from bacteria. This protein is capable of assembly into virus-like particles in a defined in vitro system. We have reported that it is in monomer-dimer equilibrium in solution, and have described a mutant Gag protein that remains monomeric at high concentrations in solution. We report that the mutant protein retains several properties of wild-type Gag. This mutant enabled us to analyze solutions of monomeric protein. Hydrodynamic studies on the mutant protein showed that it is highly asymmetric, with a frictional ratio of 1.66. Small-angle neutron scattering (SANS) experiments confirmed its asymmetry and yielded an R(g) value of 34 A. Atomic-level structures of individual domains within Gag have previously been determined, but these domains are connected in Gag by flexible linkers. We constructed a series of models of the mutant Gag protein based on these domain structures, and tested each model computationally for its agreement with the experimental hydrodynamic and SANS data. The only models consistent with the data were those in which Gag was folded over, with its N-terminal matrix domain near its C-terminal nucleocapsid domain in three-dimensional space. Since Gag is a rod-shaped molecule in the assembled immature virion, these findings imply that Gag undergoes a major conformational change upon virus assembly.     

Pleiotropic effects of a vibrio extracellular protease on the activation of contact system

Many proteases secreted by pathogenic bacteria can affect seriously on hemostatic system. We have reported that an extracellular zinc metalloprotease (named vEP-45) from Vibrio vulnificus ATCC29307 activates prothrombin to active thrombin, leading the formation of fibrin clot. In this study, the effects of vEP-45 on the intrinsic pathway of coagulation and the kallikrein/kinin system were examined. The protease could activate proteolytically clotting factor zymogens, including FXII, FXI, FX, and prothrombin, to their functional enzymes in vitro and plasma milieu. In addition, it could cleave plasma prekallikrein (PPK) to form an active kallikrein as well as actively digest high-molecular weight kininogen (HK), probably producing bradykinin. In fact, vEP-45 could induce a vascular permeability in a dose-dependent manner in vivo. Taken together, the results demonstrate that vEP-45 can activate plasma contact system by cleaving key zymogen molecules, participating in the intrinsic pathway of coagulation and the kallikrein/kinin system.     

4种香薷的花粉和果实形态扫描电镜比较观察

４种香薷的花粉和果实形态扫描电镜比较观察胡珊梅范崔生（厦门市药品检验所厦门３６１０１２）（江西中医学院药学系南昌３３０００６）关键词香薷;江香薷;花粉;果实;扫描电镜ＴＨＥＳＣＡＮＮＩＮＧＥＬＥＣＴＲＯＮＭＩＣＲＯＳＣＯＰＥＯＦＰＯＬＬＥＮＡＮＤＦＲ...     

Spotlight: Assembly of protein complexes by integrating graph clustering methods

As is generally assumed, clusters in protein–protein interaction (PPI) networks perform specific, crucial functions in biological systems. Various network community detection methods have been developed to exploit PPI networks in order to identify protein complexes and functional modules. Due to the potential role of various regulatory modes in biological networks, a single method may just apply a single graph property and neglect communities highlighted by other network properties.     

Testing top‐down and bottom‐up effects on arid zone beetle assemblages following mammal reintroduction

Species extinctions and declines are occurring globally and commonly have cascading effects on ecosystems. In Australia, mammal extinctions have been extensive, particularly in arid areas, where precipitation drives ecosystems. Many ecologically extinct mammals feed on soil‐dwelling insects. However, how this top‐down pressure affected their prey and how this contrasts with the bottom‐up impacts of fluctuating precipitation remains unclear. We constructed a long‐term exclusion experiment in a multi‐species mammal reintroduction zone in semi‐arid Australia to test how top‐down (reintroduced mammals) and bottom‐up (precipitation) factors affect root‐feeding chafer beetles (Coleoptera: Melolonthinae). We used emergence traps in ten replicate 20 × 20 m plots of control, exclusion and procedural control treatments to trap chafers biannually from 2009 to 2015. Annual precipitation during this period varied from 173 to 481 mm. Mammal exclusion did not affect chafers, indicating that top‐down regulation was not important. Instead, chafer abundance, species density and biomass increased with precipitation. Chafer body size and assemblage composition were best predicted by sampling year, suggesting that random drift determined species abundances. Increased resource availability therefore favoured all species similarly. We thus found no evidence that mammal predation alters chafer populations and conclude that they may be driven primarily by bottom‐up processes. Further research should determine if the cascading effects of species loss are less important for herbivores generally than for higher level trophic groups and the role of ecosystem stability in mediating these patterns.     

Water soluble feruloyl arabinoxylans from rice and ragi: changes upon malting and their consequence on antioxidant activity

The objective of this study is to determine the changes brought about by germination on water soluble feruloyl arabinoxylans (feraxans), one of the major components of soluble fibre from rice and ragi and their consequence on antioxidant activity. Soluble feraxans, isolated from native and malted rice and ragi were fractionated on DEAE-cellulose. Ferulic acid content of the major [0.1 molar ammonium carbonate (AC) eluted] fraction was higher in malts (rice: 1045 microg/g; ragi: 1404 microg/g) than in native (rice: 119 microg/g; ragi: 147 microg/g) and this fraction was separated by Sephacryl S-300 chromatography into two peaks each in rice (native: 232 and 24.4 kDa; malt: 75.4 and 39.6 kDa) and ragi (native: 140 and 15.4 kDa; malt: 38.9 and 15.4 kDa). 0.1 molar AC eluted fractions showed very strong antioxidant activity in vitro as determined by beta-carotene-linoleate emulsion (IC50: 0.16-0.24 mg), DPPH* (IC50: 4.1-11.4 mg) and Ferric reducing/antioxidant power, FRAP (EC1: 0.76-3.1mg) assays. Antioxidant activity of feraxans was several (4.9-1400) folds higher than the expected activity due to their bound ferulic acid content. Apart from ferulic acid, presence of sugars with >C=O (uronyl/acetyl) groups and degree/nature of glycan-polymerization were observed to influence antioxidant activity of the polysaccharides. Malting resulted in many dynamic changes in the ferulic acid content in different feraxan types and affected their antioxidant activity.     

Morphological and Molecular Characterization of Pomegranate Fruit Rot Pathogen, <Emphasis Type="Italic">Chaetomella raphigera</Emphasis>, and its Virulence Factors

A new fungal pathogen was isolated from rotten pomegranates collected from the orchards of different parts of Maharashtra. The pathogen was morphologically identified as Chaetomella raphigera followed by sequencing of ITS and D1/D2 hypervariable region of LSU (28S) of rRNA gene. The pathogen produced pectinase, cellulase, xylanase and protease in liquid medium at a concentration of 71, 13.8, 54.3 and 7 U/ml respectively. Enzyme activity was also determined during pathogenesis in the tissues artificially infected by C. raphigera. Xylanase activity was maximum (25.1 U/g) followed by pectinase (19.2 U/g) and cellulase (1.5 U/g), whereas, protease activity was unnoticed. There was significant correlation (P < 0.05) between disease rating scale and pectinase, xylanase and cellulase activity in infected tissues. This indicates the simultaneous production of hydrolytic enzymes that aids in necrosis of fruit tissues. The elevated levels of these enzymes in infected tissues as compared with control suggest their possible role in pathogenesis. Thus, pectinase, cellulase and xylanase produced by C. raphigera acts as major virulence factors in the development of fruit rot in pomegranates. This is a first report of fungal fruit rot caused by C. raphigera in pomegranate.     

不同供氮水平下施硅对辣椒产量与营养品质及其养分吸收利用的影响

为探究不同供氮水平下施硅对辣椒产量、果实品质及养分吸收利用的影响,以辣椒品种‘奥黛丽’为试验材料,采用基质栽培,设置正常施氮肥（1.0N：260.9 kg/667 m2）、氮肥减施40%（0.6N：149.1 kg/667 m2）、氮肥减施60%（0.4N：104.3 kg/667 m2）、不施氮肥（0N：0 kg/667 m2）4个不同供氮（基施）水平和2个硅肥（根施）水平（0 mmol/L、1.5 mmol/L）,研究不同供氮水平下硅对辣椒产量、品质及氮肥利用效率的影响效应,并筛选出最佳施肥处理,旨在为辣椒的增产提质提供理论基础和技术参考。结果表明：（1）0.6N供氮水平较1.0N、0.4N和0N供氮水平下的辣椒果实产量分别提高了7.18%、74.14%和87.99%,施硅处理后则进一步促进了果实产量,其中0.6N供氮水平下施硅较正常供氮量下的辣椒果实产量提高了15.33%;（2）0.6N供氮水平更有利于促进辣椒果实中可溶性糖、还原糖、可溶性蛋白、维生素C含量的提高和可滴定酸、NO3?含量的降低,施硅后不同供氮水平下辣椒果实品质均显著提高;（3）0.6N供氮水平更有利于辣椒果实矿质元素的积累与土壤氮肥利用率的提高,其中0.6N供氮水平较1.0N供氮水平下的氮肥利用率与氮肥农学效率分别显著提高了97.57%和69.20%,施硅处理后不同供氮水平下辣椒果实矿质元素含量与土壤氮肥利用率均显著提高;（4）通过对辣椒产量及果实品质指标的主成分分析,结果表明,0.6N+Si处理下的综合得分最高,即氮肥减施40%配施1.5 mmol/L的外源硅肥对辣椒产量、品质及氮肥的吸收利用促进效果最佳。