甲硫氨酸诱导高Hcy血症的抗氧化作用研究

为探讨甲硫氨酸在诱导高Hcy血症过程中的抗氧化作用,将Wistar大鼠随机分为正常组和1%甲硫氨酸组,喂养6周后,采用高效液相色谱法测定血清中同型半胱氨酸(Hcy)和谷胱甘肽含量(GSH),全自动氨基酸分析仪测定蛋氨酸和牛磺酸含量,转氨酶活性采用试剂盒测定。肝组织丙二醛(MDA)含量采用硫代巴比妥酸法,黄嘌呤氧化酶法和比色法测定肝组织超氧化物歧化酶(SOD)活性、总抗氧化能力(FRAP值)和还原性谷胱甘肽含量。结果表明,1%甲硫氨酸组血清Hcy和牛磺酸含量分别为3.56±0.68μmol·L-1和568.68±57.02μmol·L-1,较正常组显著升高(p<0.05)。1%甲硫氨酸组肝组织GSH含量和SOD活性分别为132.19±25.49mg·g-1和6.86±1.46U·mg-1,较正常组103.97±16.30mg·g-1和5.01±1.24U·mg-1显著升高(p<0.05)。1%甲硫氨酸组较正常组肝组织FRAP值亦升高而MDA含量降低。结果表明,甲硫氨酸在诱导高Hcy血症过程中同时具有抗氧化作用。     

温度、盐度和食物条件对西藏拟溞摄食强度的影响

报道了不同温度、盐度和饵料条件下西藏拟溞的摄食强度、西藏拟溞对不同饵料生物蛋白核小球藻(Chlorellapyrenoidesa)、牟氏角毛藻(Chaetoceros muelleri)、湛江等鞭金藻(Isochrysis zhanjiangensis)、亚心形扁藻(Platymonas subcordiformis)、盐藻(Dunaliella salina)、新月拟菱形藻(Nitzschiella closterium)的选择性以及摄食节律。结果表明,在适温范围(2 20℃)内,西藏拟溞的滤水率、摄食率随着温度的升高而增加,14 16℃为西藏拟溞的适宜温度。在盐度20时,西藏拟溞的摄食率最高,幼、成溞对等鞭金藻的摄食率分别为1.88 ng C/(ind.h)和3.46 ng C/(ind.h)。西藏拟溞对角毛藻的滤水率和摄食率均随着龄期增加而增加,而对等鞭金藻呈相反趋势,但二者的日粮均随体长增大而减小。幼、成溞的滤水率和摄食率随食物密度变化的趋势基本一致,均是在盐藻密度为1×106 ind./L时均最高,分别为0.194、0.221 mL/(ind.h)和0.030μgC/(ind.h)和0.034μgC/(ind.h)。幼溞对6种藻的食物选择性为角毛藻小球藻盐藻扁藻金藻拟菱形藻;成溞为扁藻角毛藻盐藻金藻小球藻拟菱形藻。幼溞、成溞均对角毛藻和盐藻的选择性较好。西藏拟溞的幼溞和成溞对牟氏角毛藻的摄食有相同的节律,在15:00 17:00和01:00 03:00时有两个摄食高峰,在09:00 11:00和23:00 01:00有两个低谷。     

温度和盐度对褐牙鲆幼鱼渗透生理及抗氧化水平的影响简

采用双因素析因实验设计方法,研究了温度(20℃、24℃、28℃)和盐度(10‰、30‰)急性应激对褐牙鲆(Paralichthys olivaceus)幼鱼渗透生理和抗氧化水平的影响。结果表明:盐度和温度变化对各实验组1d和6d时褐牙鲆幼鱼血浆皮质醇含量均无显著性差异。在高温低盐(28℃、10‰)环境中1d时渗透压显著高于其他各实验组,6d时无显著性差异。牙鲆幼鱼在28℃环境中1d时鳃Na+-K+-ATP酶活性显著高于20℃和24℃;6d时,温度和盐度对牙鲆幼鱼鳃Na+-K+-ATP酶活性有显著交互影响作用。1d时,随着温度的升高或盐度的降低牙鲆幼鱼肝脏超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性呈现上升趋势,并且高温低盐(28℃、盐度10‰)组褐牙鲆幼鱼肝脏丙二醛(MDA)含量显著高于其他各组;在3个实验温度下,10‰环境中牙鲆幼鱼肝脏脂质过氧化物(LPO)的含量高于30‰。在6d时,各实验组间肝脏SOD、CAT活性及MDA含量无显著性差异。因此,褐牙鲆能够耐受温度20—28℃和低至盐度10‰的环境条件,应激早期温度和盐度的变化可引起褐牙鲆幼鱼渗透生理和抗氧化水平的变化,高温低盐对褐牙鲆幼鱼抗氧化水平的影响最大,至6d可基本恢复稳定。     

温度和盐度对褐牙鲆幼鱼渗透生理及抗氧化水平的影响

采用双因素析因实验设计方法,研究了温度（20℃、24℃、28℃）和盐度（10、30）急性应激对褐牙鲆（Paralichthys olivaceus）幼鱼渗透生理和抗氧化水平的影响。结果表明:盐度和温度变化对各实验组1d和6d时褐牙鲆幼鱼血浆皮质醇含量均无显著性差异。在高温低盐（28℃、10）环境中1d时渗透压显著高于其他各实验组,6d时无显著性差异。牙鲆幼鱼在28℃环境中1d时鳃Na+-K+-ATP酶活性显著高于20℃和24℃;6d时,温度和盐度对牙鲆幼鱼鳃Na+-K+-ATP酶活性有显著交互影响作用。1d时,随着温度的升高或盐度的降低牙鲆幼鱼肝脏超氧化物歧化酶（SOD）和过氧化氢酶（CAT）活性呈现上升趋势,并且高温低盐（28℃、盐度10）组褐牙鲆幼鱼肝脏丙二醛（MDA）含量显著高于其他各组;在3个实验温度下,10环境中牙鲆幼鱼肝脏脂质过氧化物（LPO）的含量高于30。在6d时,各实验组间肝脏SOD、CAT活性及MDA含量无显著性差异。因此,褐牙鲆能够耐受温度2028℃和低至盐度10的环境条件,应激早期温度和盐度的变化可引起褐牙鲆幼鱼渗透生理和抗氧化水平的变化,高温低盐对褐牙鲆幼鱼抗氧化水平的影响最大,至6d可基本恢复稳定。       

温度和紫外辐射胁迫对西藏飞蝗抗氧化系统的影响

为探讨西藏飞蝗(Locusta migratoria tibetensis Chen)对环境的适应机制,报道了温度和紫外辐射胁迫对西藏飞蝗抗氧化系统影响。以西藏飞蝗成虫为试材,研究5—20℃低温、30—45℃高温胁迫和紫外线辐射对其抗氧化酶活性和膜脂过氧化物丙二醛(MDA)含量的影响。在5—20℃低温胁迫下,成虫体壁和消化道超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性及丙二醛(MDA)含量分别随温度降低而升高;在30—35℃高温胁迫下,成虫SOD、POD和CAT活性分别随温度升高而升高,当温度超过35℃时,3种氧化酶活性均下降。长波紫外辐射(UV-A)和中波紫外辐射(UV-B)对处理后24h和72h成虫的SOD活性的影响大于可见光,在UV-A、UV-B和可见光3种光波长处理下,成虫的POD和CAT活性随光照时间的延长而增加,其中UV-B对两种酶活性影响大于UV-A和可见光,表现为UV-B处理组>UV-A处理组>可见光处理组;UV-A和UV-B处理能导致虫体体壁MDA含量明显升高,且对脂质过氧化的诱导存在时间效应;雌虫体壁、雌虫消化道、雄虫体壁和雄虫消化道的MDA含量分别在UV-B72h、UV-A72h、UV-A72h和UV-B72h达最大值0.72、0.88、0.66和0.94 nmol/g鲜重。在20—5℃低温胁迫下,西藏飞蝗成虫抗氧化酶活性升高,能较好的保护自身免遭活性氧自由基的伤害;西藏飞蝗对高温忍耐力差,在高于35℃高温胁迫下,成虫SOD、POD、CAT活性均下降;在长波和中波紫外辐射下,西藏飞蝗抗氧化酶活性显著升高,是西藏飞蝗对紫外线辐射强度大的青藏高原的一种重要适应。     

温度、盐度和体长对西藏拟溞（Daphniopsis tibetana Sars）排氨率的影响

在实验室内研究了温度(T=3、8、14、20 ℃和22 ℃)、盐度(S=5、10、15、20 和 25)和体长(0.80、1.23、1.51、1.84 mm和2 38 mm)对西藏拟溞排氨率(NR)的影响.结果表明,在试验温度范围内,西藏拟溞幼溞排氨率随温度(T)的升高而升高,其回归方程为 NR=0.0359Ln(T)-0.0185 (n=5, r=0.9881, P<0.05),数值范围为 0.022~0.092 mg/(g·h).在盐度(S)试验中,西藏拟溞幼溞排氨率有同样的趋势,回归方程为NR = 0.0535e0.0213S(n=5, r=0.9884),其数值范围为0.061~0.092mg/(g·h).而体长试验中,西藏拟溞排氨率随体长(L)的增加而降低,回归方程为NR=0.0568L-1.4154(n=5, r=0.9938, P<0.05),数值范围为0.017~0.083mg/(g·h).     

高温高湿胁迫下茉莉酸甲酯对紫苏种子萌发及生理特性的影响

以紫苏品系GS011种子为材料,在温度为50℃、空气相对湿度为95%、时间为12h的胁迫条件下,研究不同浓度(0.05、0.10、0.15、0.20和0.25mmol.L-1)茉莉酸甲酯(MeJA)对紫苏种子萌发、幼苗生长、叶片氧化损伤和抗氧化酶活性的影响。结果表明:0.15mmol.L-1 MeJA处理能显著缓解高温高湿对紫苏种子生长发育造成的胁迫伤害,使紫苏种子发芽率、发芽势、发芽指数、活力指数均达到最大值,分别为40.84%、31.83%、8.83和1.35;同时使其叶片MDA含量最低(0.15μmol.g-1),SOD、CAT、LOX、POD和APX活性均达到最大值,分别为0.27U.mg-1及4.7、5.7、4.9和8.9U.g-1.min-1。研究发现,MeJA在一定程度上能提高SOD等保护酶的活性,缓解高温高湿造成的氧化损伤,有效促进高温高湿胁迫下紫苏种子的萌发和幼苗生长。     

镉胁迫对旱柳细胞膜透性和抗氧化酶活性的影响

以‘Fuyang 3’旱柳为材料,通过水培方法研究了中、高剂量(5、25μmol.L-1)镉胁迫下旱柳器官的镉(Cd2 )积累、叶和根细胞膜渗透及抗氧化酶活性的变化。结果表明:Cd2 主要积累在旱柳的根部(最高达1 297.71μg.g-1),其次是枝条(最高为163.13μg.g-1)。中、高剂量Cd2 胁迫下,旱柳叶相对电导率、根K 渗透以及根和叶丙二醛(MDA)含量均未发生显著变化。中、高剂量Cd2 胁迫使旱柳根系的超氧歧化酶(SOD)、抗坏血酸过氧化物酶(APX)和谷胱甘肽转移酶(GST)活性,以及叶片的SOD、愈创木酚过氧化酶(POD)、谷胱甘肽过氧化物酶(GPX)和GST活性均比对照显著增强;且高剂量胁迫旱柳根系的SOD和GST活性,及其叶片的POD、GPX和GST活性均显著高于相应中剂量胁迫。研究发现,旱柳在不同浓度镉胁迫条件下,其根是Cd2 主要积累器官,其叶和根细胞质膜能保持相对稳定性,其根和叶各抗氧化酶活性发生不同程度改变,从而使旱柳对Cd2 胁迫表现出一定的忍耐性。     

碱度和pH对西藏拟溞存活、生长和生殖的影响

在温度为16±0.5℃和盐度15.5±0.5的条件下,研究了碱度和pH对西藏拟溞（Daphniopsis tibetanaSars）存活、生长和生殖的影响。结果表明,西藏拟溞的24h半致死pH为4.18和10.84;48h半致死pH为4.37和10.71;24h和48h半致死碱度分别为529.43mmol/L和503.69mmol/L。西藏拟在培养液的pH7—8时,生长率和存活率显著高于其他各组。pH7时,西藏拟溞的内禀增长率最大,为0.3014/d。pH8时次之,为0.2924/d。西藏拟溞在各碱度组中的生长率和存活率差异不显著。碱度为11.9mmol/L时,西藏拟溞产幼前发育期最短,为18.70±0.65d。在碱度11.9和18.9mmol/L时,其产卵率为1.1671和1.1877,高于其他各组。西藏拟溞在碱度为7.54mmol/L组中的rm最高,为0.3425/d,其他各组的rm在0.2889—0.3276/d之间。西藏拟溞生存的最适pH为7—8,最适碱度为4.75—18.9mmol/L。     

温度胁迫下淫羊藿的膜脂过氧化和保护酶活性

采用分光光度法测定了箭叶淫羊藿在不同温度处理后的过氧化物酶（POD）活性,超氧化物歧化酶（SOD）活性及丙二醛（MDA）含量,发现在高温胁迫下POD活性,SOD活性,MDA含量均呈上升趋势,而在低温胁迫下,POD活性,SOD活性下降,而MDA含量在0℃以上低温下降,0℃以下低温又开始上升;在25℃时,POD活性,SOD活性,MDA含量均处于最低水平。     

Y-chromosome Data and Tribal Affiliations of Allenopithecus and Miopithecus

The phylogeny of Old World monkeys has remained unresolved in part because of a lack of resolution in the Cercopithecinae. Competing morphological hypotheses have had Allen's swamp monkey (Allenopithecus nigroviridis) and the talapoins (Miopithecus spp.) as basal branches of either the tribe Cercopithecini or the tribe Papionini. Previous molecular analyses have not adequately addressed the issue. To better understand the evolutionary history of these primates, we sequenced and subjected to phylogenetic analysis 3.1 kb of 2 loci (TSPY and SRY) from the non-recombining portion of the Y-chromosome. Individuals from the genera Allenopithecus, Miopithecus, Erythrocebus, Chlorocebus, and Cercopithecus were surveyed and their sequences compared with those previously published for the Papionini and Colobinae. The results suggest Allenopithecus and Miopithecus are more closely related to the Cercopithecini than Papionini. Our data also support the hypothesis that within the Cercopithecini, Erythrocebus and Chlorocebus share a close evolutionary relationship, distinct from the other members of the tribe.     

Nystatin and killer toxin sensitivity of free and immobilizedSaccharomyces cerevisiae

The inhibitory effect of nystatin and killer toxin on the growth of free and covalently-immobilizedSaccharomyces cerevisiae cells was studied. The resistance of immobilized cells to both agents was accompanied by increased amounts of phospholipids and sterols. The possible relationship between these changes in the membrane composition and the transduction of a signal across the cytoplasmic membrane is discussed.     

The hernandez and fernandez genes of Drosophila specify eye and antenna

The formation of different structures in Drosophila depends on the combined activities of selector genes and signaling pathways. For instance, the antenna requires the selector gene homothorax, which distinguishes between the leg and the antenna and can specify distal antenna if expressed ectopically. Similarly, the eye is formed by a group of "eye-specifying" genes, among them eyeless, which can direct eye development ectopically. We report here the characterization of the hernandez and fernandez genes, expressed in the antennal and eye primordia of the eye-antenna imaginal disc. The predicted proteins encoded by these two genes have 27% common amino acids and include a Pipsqueak domain. Reduced expression of either hernandez or fernandez mildly affects antenna and eye development, while the inactivation of both genes partially transforms distal antenna into leg. Ectopic expression of either of the two genes results in two different phenotypes: it can form distal antenna, activating genes like homothorax, spineless, and spalt, and it can promote eye development and activates eyeless. Reciprocally, eyeless can induce hernandez and fernandez expression, and homothorax and spineless can activate both hernandez and fernandez when ectopically expressed. The formation of eye by these genes seems to require Notch signaling, since the induction of ectopic eyes and the activation of eyeless by the hernandez gene are suppressed when the Notch function is compromised. Our results show that the hernandez and fernandez genes are required for antennal and eye development and are also able to specify eye or antenna ectopically.     

Molecular identification and differentiation of Brevibacterium species and strains

Amplified ribosomal DNA restriction enzyme analysis (ARDRA), pulsed field gel electrophoresis (PFGE) and ribotyping were used to differentiate among 24 strains of Brevibacterium linens, Brevibacterium casei and Brevibacterium epidermidis obtained from type culture collections or isolated from various smear ripened cheeses. ARDRA was applied to the 16S rDNA. B. linens was shown to be a quite heterogenic group with 2 to at least 4 copies of rrn operons per strain with aberrant nucleotide sequences. AccI gave genus specific restriction patterns and was used to separate Brevibacterium from Corynebacterium species. The expected species specificity of TaqI applied to B. linens type culture strains, but not to all strains isolated from cheese. By AvaI restriction, B. casei and B. linens were differentiated from B. epidermidis and the orange pigmented Arthrobacter casei, a new species of coryneform bacteria; by XmnI restriction, B. linens and B. epidermidis were differentiated from B. casei. One of 4 B. linens genotypes could not be distinguished from B. casei by this method. Here, the typical orange B. linens pigments were used for classification, which was confirmed by partial sequencing of the 16S rDNA.     

Evaluation of antiprotozoal and antimycobacterial activities of the resin glycosides and the other metabolites of Scrophularia cryptophila

Resin glycosides are secondary metabolites exclusive to the convolvulaceous plants. In this study, crypthophilic acids A–C (1–3), the first resin glycosides occurring in another family (Scrophulariaceae), and the other constituents of Scrophularia cryptophila were examined for in vitro antiprotozoal and antimycobacterial potentials. Except for crypthophilic acid B (2), all tested compounds exhibited growth-inhibitory effect against Trypanosoma brucei rhodesiense, with l-tryptophan (6) and buddlejasaponin III (7) being the most potent ones (IC₅₀'s 4.1 and 9.7 μg/ml). In contrast, the activity towards Trypanosoma cruzi was poor, and only crypthophilic acid C (3), 6 and 7 were trypanocidal at concentrations above 40 μg/ml. With the exception of 2 and 6, all compounds were active against Leishmania donovani. Harpagide (4) and 3 emerged as the best leishmanicidal agents (IC₅₀'s 2.0 and 5.8 μg/ml). Only compounds 3, 6 and 7 showed antimalarial activity against Plasmodium falciparum with IC₅₀ values of 4.2, 16.6 and 22.4 μg/ml. Overall the best and broadest spectrum activity was presented by compounds 3 and 7, as they inhibited all four parasitic protozoa. None of the isolates had significant activity against Mycobacterium tuberculosis (MICs >100 μg/ml) or were toxic towards mammalian (L6) cells. This is the first report of antiprotozoal activity for natural resin glycosides, as well as for harpagide (4), acetylharpagide (5), tryptophan (6) and buddlejasaponin III (7).     

Theoretical Study of Antagonists and Inhibitors of Mammalian Adenosine Deaminase: I. Adenosine and Its Aza- and Deazaanalogues

Aza- and deazaanalogues of adenosine, including their 1-protonated forms (except for that of 1-deazaadenosine), were studied by computer computation to find a relationship between their molecular structures and substrate properties for the mammalian adenosine deaminase. The atomic charge distribution and maps of the electrostatic potential around their van der Waals molecular surface were calculated for these compounds using the ab initio STO-3G method. The conformational studies are carried out by the MM⁺ method of molecular mechanics. The mechanism that determines the substrate selectivity of mammalian adenosine deaminase is discussed.     

Effects of carbon concentration and carbon to nitrogen ratio on the growth and sporulation of several biocontrol fungi

Effects of carbon concentration and carbon to nitrogen (C:N) ratio on six biocontrol fungal strains are reported in this paper. All fungal strains had extensive growth on the media supplemented with 6–12 g l⁻¹ carbon and C:N ratios from 10:1 to 80:1, and differed in nutrient requirements for sporulation. Except for the two strains of Paecilomyces lilacinus, all selected fungi attained the highest spore yields at a C:N ratio of 160:1 when the carbon concentration was 12 g l⁻¹ for Metarhizium anisopliae SQZ-1-21, 6 g l⁻¹ for M. anisopliae RS-4-1 and Trichoderma viride TV-1, and 8 g l⁻¹ for Lecanicillium lecanii CA-1-G. The optimal conditions for P. lilacinus sporulation were 8 g l⁻¹ carbon with a C:N ratio of 10:1 for M-14 and 12 g l⁻¹ carbon with a C:N ratio of 20:1 for IPC-P, respectively. The results indicated that the influence of carbon concentration and C:N ratio on fungal growth and sporulation is strain dependent; therefore, consideration for the complexity of nutrient requirements is essential for improving yields of fungal biocontrol agents.     

Pericarp structure and phylogeny of theLamiaceae-Verbenaceae-complex

Pericarp structure was investigated in 158 species of the familiesLamiaceae andVerbenaceae. Data from 221 out of 262 genera ofLamiaceae s.l. and a few ofVerbenaceae s.str. were collected in a table. A cladistic analysis was performed on the basis of pericarp characters only. The abandonment of subfam.Pogostemonoideae as a taxonomic unit is considered. Examples of groups given additional support by similarities in pericarp characters are: (1) the gynobasic-styled labiates (subfamiliesPogostemonoideae, Lamioideae, Nepetoideae); (2) aLamioideae-Pogostemonoideae-group; (3)Nepetoideae; (4) aWestringia-Hemigenia-Hemiandra-Microcorys group (in subfam.Chloranthoideae); (5) aLepechinia-Chaunostoma-group (inNepetoideae); (6) aPrunella-Cleonia-group (inNepetoideae).     

Spatial and temporal patterns of morel fruiting

The biotic and abiotic factors conditioning morel fruit body production are incompletely known. We examined spatial and temporal patterns of Morchella esculenta fruiting over five years in a wooded site in Missouri, USA. Fruiting onset was inversely correlated with spring air and soil temperatures, whereas abundance was positively correlated with rain events (>10 mm) during the 30 d preceding fruiting. The two years with the greatest fruiting had the shortest fruiting seasons (6–7 d). Fruiting season length was positively correlated with soil warming, suggesting that a narrow range of optimum soil temperatures favour the explosive production of fruit bodies. All woody stems of at least 1 cm diam were mapped and stem diameter and crown condition were noted. Morel fruit bodies were significantly closer to stems of Carya spp., Tilia americana and Ulmus americana than predicted by the frequencies of these woody species or their contribution to the total basal area on the site. Although intra-annual clustering of fruit bodies was often observed, inter-annual clustering was not. The spatial pattern of M. esculenta fruiting appears to be associated with vegetation pattern, whereas the onset and abundance of fruiting are determined by the interaction of spring temperatures with availability of supporting precipitation.     

Origin and development of Tool-making behavior in Africa and Asia

Around two-and-a-half million years ago, some hominid populations in Africa began to modify stones and bones in a manner that can be recognized by prehistorians as artifacts, and, by definition, produced the earliest identifiable archaeological record. It is likely that earlier hominid groups also may have had relatively rich tool-using behavioral repertoires similar to that seen in modern chimpanzees (McGrew, 1992), such tools may have been made of perishable materials or minimally modified and thus difficult to identify. This review will focus on the earliest archaeological traces and the spread of hominids out of Africa and into Eurasia.