不同化学杂交剂(CHA)对小麦花药同工酶影响的研究

在小麦叶枕距±2cm时,喷施4种不同化学杂交剂（CHA）后,分别取小孢子处于不同发育阶段的花药,进行过氧化酶（POD）、淀粉酶（Amy）和酯酶（Est）等同工酶的分析。研究表明：在小孢子母细胞减数分裂期,处理2、3和4三种CHA对POD的A1、A2;B2、B4和B5,C1、C2和C3同工酶带的活性均有明显的抑制作用;处理5除去对A1和A2表现抑制外,对其他酶带的活性均有增强作用。在单枚早期,处理2和3的A、B和C区POD同工酶活性均明显低于对照;处理4和5上述各区POD同工酶活性却明显高于对照。在上述两个发育时期,处理2对Amy1区酶活性有增强作用,而处理3、4和5对该区酶活性却表现了专一性的抑制。各处理对Est同工酶A区和B区的酶活性主要表现为抑制。实验结果表明,不同的CHA均通过干扰花药的物质和能量代谢而导致雄性生理性不育。     

铅对绿豆幼苗生长的影响

Effects of Pb^2 on the growth of mung bean(Phaseolus radiatus L.)seedlings were conducted with an experiment.The results showed that the dry weight of roots increased by 13.01%,the dry weight of shoots decreased by 12.80%,the free proline and MDA content in leaves increased specially by 2.07% and 5.82%,the activity of POD decreased by 37.32% compared to control under 0.05mmol/L Pb^2 treatment.Under 0.5mmol/L Pb^2 treatment,the dry weights of roots and shoots decreased specially be 14.45% and 29.36%,the free proline and MDA content in leaves increased specially by 43.55% and 28.50,the activity of POD decreased by 59.37% compared to control.The results indicated that Pb^2 interfered the growth of mung bean seedlings by destroying cell membrane intergrity and decreasing the activity of POD in leaves.     

杜仲剥皮再生过程中可溶性蛋白和过氧化物酶含量及分布的变化(英文)

Peroxidases are known to play important roles in plant wound healing. Biochemical analysisand histochemical localization techniques were used to assess changes and distribution of peroxidases inthe recovering bark after girdling in Eucommia ulmoides Oliv. Between 4 and 21 days after girdling (DAG),peroxidases activity in the girdled trees significantly increased by 30-40 times over that in ungirdled trees.During the whole bark recovery process (from 0 to 63 DAG), the peroxidase signal was not found in thetissue regions subjected to intense cell division activity (regenerating cambial zone and phellogen). However,high peroxidase activity was detected in the callus, cortex-like, mature phloem and xylem. Interestingly, itwas shown that, in maturing xylem and phloem cells, there was respectively an inward and outwardperoxidase activity gradient on both sides of the cambium zone. An isoelectric-focusing electrophoresis ofthe extracted protein displayed two isozyme bands of peroxidase: POD Ⅰ and POD Ⅱ. POD Ⅰ was onlydetected in the xylem fraction and could play a role in xylem differentiation. POD Ⅱ was only identified inthe recovering bark portion and could be more engaged in bark regeneration process. A relationshipbetween IAA and peroxidase is also discussed.     

Eco-physiological responses of the declining population Spartina anglica to N and P fertilizer addition

Nitrogen and phosphorus are both important life elements. N, P and combined N-P fertilizers were added to the declining population Spartina anglica Hubbard in coastal China. Some growth parameters and eco-physiological responses of S. anglica to different fertilizer treatments (N, P and combined N-P fertilizer addition with high, medium and low levels, respectively) were measured. The fertilizer addition had a highly significant effect on the dynamics of its height-growth, number of leaves, number of roots and total biomass. Only N addition had a significant effect on leaf area and leaf thickness in all fertilizer treatments. On the dynamics of its height-growth, the effect of N addition was the most apparent, and the effect of N-P addition was not greater than those of N and P addition separately. The photosynthesis rate was enhanced and the yield was the highest with the highest N, the highest N-P and the medium P addition. The rates were higher than those of CK by 19.08 μmol·m^?2·s^?1, 15.47 μmol·m^?2·s^?1 and 11.23 μmol·m^?2·s^?1, respectively. The activity of SOD and POD increased with the treatments after freshwater stress for 14 days. Effects of medium N and P addition were significant for SOD activity. However, POD activity was significantly higher with the treatment of higher N and higher N-P addition. In a word, fertilizer addition improved the growth of the declining population S. anglica. The results indicated that the decline of S. anglica was correlated with the nutriment deficiency in soil, especially with the lack of N.     

柠檬形克勒克酵母对温州蜜柑“国庆一号”采后贮藏的防腐效果

Citrus unshiu “Guoqing No.1” was used as material for elucidating the effect of Kloeckera apiculata suspension post-harvest treatment on preventing fruit decay during storage period. The result showed that K. apiculata preparation of 2×106CFU/mL (CFU, cloning forming unit) significantly reduced the development of decay caused by green mold, blue mold and stem rot, showing the same effect of carbendazim treatment after storage period of 100 days, and the disease incidence was controlled under 1%. The antagonist population was between 3.5×105CFU/mL and 1.7×107CFU/mL in citrus fruit, and increased 1.7×107CFU/mL after 40 days storage, and then stabilized for the remaining storage period. After storage at 5℃ for 100 days, K. apiculata strain 34-9 did not alter any quality parameters of fruit. During storage, the change of relative electrical conductivity (REC) showed a coordinate tendency with malondlaldehyde (MDA) content, which kept continuously growing from the beginning to the end of the storage. In the storage period of 25 days, the REC value and MDA content of the treatments were all significantly lower than those of water treatment, but had no obvious difference from those of carbendazim treatment. K. apiculata strain 34-9 had no effect on the enzyme activity of super oxide dismutase (SOD), but significantly improved peroxidase (POD) activity after 100 day storage.     

Activation In Vitro of Mutant MoFe Proteins from Azotobacter vinelandii by Reconstituent Solutions

nifB-MoFe protein （nifB-Av1）, AnifE MoFe protein （△nifE Av1） and AnifZ MoFe protein （△nifZ Av1） were obtained by chromatography on DE52, Sephacryl S-300 and Q-Sepharose columns from nifB point-mutated, nifE deleted and nifZ deleted mutant stains （UW45, DJ35 and DJ194） of Azotobacter vinelandii Llpmann, respectively. When complemented with nltrogenase Fe protein （Av2）, AnifZ Av1 had partial activity and both nifB-Avl and △nifE Av1 had hardly any activity, but could be obviously activated by FeMoco extracted from wild-type MoFe protein （OP Av1） or △nifZ Av1. After being Incubated with excess O-phenanthrollne （O-phen） for 150 mln at 30 ℃ and subjected to chromatography on a Sephadex G-25 column In an Ar atmosphere, nifB- Av1C, △nifE Av1C and △nifZ Av1C were obtained, respectively. Based on a calculation of Fe atoms In the Ophen-Fe compound with ε 512nm = 11 100, lost Fe atoms of nifB-Av1, △nifE Av1 and △nifZ Av1 were estimated to be 1.35, 2.89 and 8.44 per molecule of protein, respectively. As a result of the Fe loss, △nifZ Av1 loses Its original activity. In the presence of both MgATP and Av2, these Fe-loslng proteins, but not the original proteins untreated with O-phen, could be significantly activated by reconstltuent solution （RS） composed of dlthlothreltol, ferric homocltrate, Na2S and Na2MoO4, or K2CrO4, or KMnO4. But In the absence of MgATP or Av2, the activation did not occur, with the exception that △nifZ AvlC was partially activated, and the activity was only 17%. These findings Indicate that： （I） △nifZ Avl with half P-cluster content Is somewhat different from FeMoco-deflclent nifB-Avl and ,△nifE Av1 with respect to protein conformation either before or after treatment with O-phen; （11） full activation of these proteins with RS requires pretreatment with O-phen and the simultaneous presence of MgATP and Av2.     

Isolation and characterization of insecticidal activity of （Z）- asarone from Acorus calamus L.

The insecticidal activity of Acorus calamus L. rhizome-derived material against adults of Sitophilus zeamais Motschulsky was examined by using repellency method and contact toxicity. The biologically active constituent of the A. calamus rhizome was separated and identified. The results showed that the ethanol extract of A. calamus had strong repellency and contact effect to S. zeamais and the active constituent of the A. calamus was characterized as （Z）-asarone by spectroscopic analysis. Responses from the tests varied with exposure times and doses. In the repellency test, ethanol extract of A. calamus had 93.92% repellency at 629.08 μg/cm^2 but only 71.38% at 157.27 μg/cm^2 12 h after treatment. As a contrast, （Z）-asarone showed 84.50% repellency at 314.54μg/cm^2 and 77.02% at 78.63 μg/cm^2 12 h after treatment. In the filter paper diffusion test, ethanol extract of A. calamus caused 95.56% and 17.78% mortality to S. zeamais at 314.54 μg/cm^2 and 78.63 μg/ cm^2 4 days after treatment, while （Z）-asarone brought about 100.00% and 15.56% mortality at 40.89 μg/cm^2 and 15.73 μg/cm^2 respectively. These results indicate that the insecticidal activity of the A. calamus extract may be due to （Z）-asarone.     

暗纹东方TUN 同工酶生化表现型的研究

利用聚丙烯酰胺凝胶垂直平板电泳方法,对暗纹东方|TUN|的心、肝、肾、肌、性腺5种不同组织的7种同工酶(EST、LDH、POD、MDH、SOD、SDH、α-AMY)进行了研究, 讨论了各同工酶的基因表达谱式,观察到EST同工酶存在着多态现象;LDH同工酶有二个基因位点,但只表现3条带,A与B亚基的结合受阻; MDH同工酶存在性别差异,说明决定MDH同工酶表达的因素在不同性别中存在差异;SOD同工酶有3个基因位点。各同工酶酶谱稳定,有组织特异性,但EST、MDH、SOD、POD同工酶在各组织器官中又表现出较大的一致性,有利于物种的鉴定。α-AMY与SDH只在个别组织中有活性,可能与特定组织与器官的形态发生与机能分化有关。 Abstract:By means of polyacrylamid gel electrophoresis seven isozymes(EST.LDH,SOD,MDH,SDH, α-AMY)in heart,liver,kidney,muscle and gonad of Fugu obscurus were studied.The gene expression patterns of each isozyme were analyzed.The results indicated that polymorphism was detected in EST isozymes;LDH isozymes had two loci,but only three bands could be observed,the random association of two subunits(A and B)were restricted;Some MDH isozymes existed sexual differences in identical tissues.The suggested that the factors controlling the expression of MDH isozymes were different between sexes.All the isozyme phenotypes exhibited tissue-specificity and stability,but EST,MDH,SOD and POD isozymes showed relatively consistence in the five tissues.Their characteristic bands could be used in species determination.The activities of SDH andα-AMY isozymes could only be detected in some tissues and closely correlated to the morphological or functional differentiation of those tissues or organs.     

Preparation of Monoclonal Antibodies against Human Ventricular Myosin Light Chain 1 （HVMLC1） for Functional Studies

Using purified recombinant human ventricular myosin light chain 1 (HVMLC 1) as the antigen,three monoclonal antibodies,designated C8,C9 and B 12,were prepared.Immunoblot experiments demonstratedthat all monoclonal antibodies could react with the ventricular myosin light chain 1 isolated from differentsources,such as human,rat or pig.It was also demonstrated that C8 was directed against the NN part of theN-fragment (amino acid 1-40) of HVMLC1,and both C9 and B12 against the C-fragment (amino acid 99-195).The affinity constants of C8,C9 and B12 were 3.20×10~8,8.60×10~7 and 1.77×10~8 M~(-1),respectively,determined by non-competitive ELISA.The isotype of B12 was determined as lgG2a,whereas the isotype ofboth C8 and C9 were IgG1.In the presence of C9 or B12,the actin-activated Mg~(2 )ATPase activity of myosinwas greatly inhibited,but there was almost no effect on the Mg~(2 )ATPase activity for C8.B12 and C9 alsoinhibited the superprecipitation of porcine cardiac native actomyosin (myosin B) and reconstituted actomyosin,but C8 did not.The results indicate that all three monoclonal antibodies could bind the intact myosin molecule,but B12 and C9 might more easily react with epitopes located in the C-fragment of HVMLC1.The inhibitoryeffects of B 12 and C9 on ATPase activity and superprecipitation assays show that light chain 1,particularlythe C-fragment domain,is involved in the modulation of the actin-activated Mg~(2 )ATPase activity of myosinand,as a consequence,plays an essential role in the interaction of actin and myosin.     

In vitro insulin refolding: Characterization of the intermediates and the putative folding pathway

The in vitro refolding process of the double-chain insulin was studied based on the investigation of in vitro single-chain insulin refolding. Six major folding intermediates, named P1A, P2B, P3A, P4B, P5B, and P6B, were captured during the folding process. The refolding experiments indicate that all of these intermediates are on-pathway. Based on these intermediates and the formation of hypothetic transients, we propose a two-stage folding pathway of insulin. (1) At the early stage of the folding process, the reduced A chain and B chain individually formed the intermediates two A chain intermediates (P1A and P3A), and four B chain intermediates (P2B, P4B, P5B, and P6B). (2) In the subsequent folding process, transient Ⅰ was formed from P3A through thiol/disulfide exchange reaction; then, transients Ⅱ and Ⅲ, each containing two native disulfides, were formed through the recognition and interaction of transient Ⅰ with P4B or P6B and the thiol group's oxidation reaction mainly using GSSG as oxidative reagent; finally, transients Ⅱ and Ⅲ, through thiol/mixture disulfide exchange reaction, formed the third native disulfide of insulin to complete the folding.     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.