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1.
本文报道来自中国沈阳的利姬蜂属一新种:弓脉利姬蜂Symphertacurvivenica,sp.nov。本新种与羚利姬蜂S.antilope(Gravenhorst)相近,可通过下列特征与后者区别:腹部第一节背板无背中脊;后小脉在下方0.2处曲折,上段稍微向基方引雌性触角鞭节三色:第1-3节黄白色,第(8)9-12(13)节白色,其余的黑色;翅基片,前足基节,中足的腿节和胫节暗褐色。  相似文献   

2.
研究了我国实姬蜂属Strongylopsis Brauns,1896,描述1新种,西藏实姬蜂Strongylopsis xizangensis sp.nov.,并附有特征图.根据Kasparyan(1974)的检索表,对世界实姬蜂属分种检索表进行了改编.模式标本保存在浙江大学膜翅目标本馆.西藏实姬蜂,新种Strongylopsis xizangensis sp.nov.(图1~11)鉴别特征 本种与中华实姬蜂S.chinensis He相似,但可从以下特征与后者区别:1)前翅小翅室近五边形(后者四边形);2)前翅1m-cu脉中央有1脉桩(后者1m-cu脉平滑,无脉桩);3)后足第3跗节短于第5节(后者等长);4)后足黑色(后者后足褐色,仅基节和转节黑色);5)后单眼间距与单复眼间距等长(后者后单眼间距短于单复眼间距).正模♀,西藏莫格(29°31 ′N,96°34′E;海拔3 772 m),2009-06-11,谭江丽采,编号200907053.分布:中国西藏.词源:新种种名源自模式标本采集地地名.中华实姬蜂Strongylopsis chinensis He,1996(图12~21)鉴别特征 本种与斑翅实姬蜂S.belua Kuzin非常相似,不同之处在于本种:1)前翅小翅室受纳2m-cu脉与端部0.28处(后者在中央处);2)前翅1cu-m脉无脉桩(后者有);3)前翅无暗斑(后者前翅在径室处有暗斑).研究标本:正模♀,青海玉树(32° 56′N,97°16′E),1981-08,邱应章采,编号820291.分布:中国青海.  相似文献   

3.
王淑芳  张连翔 《昆虫学报》1989,32(4):480-481
本文记述辽宁省樟蚕属Habronyx Foerster指名亚属Habronyx(s.str.)中一新种。模式标本保存在中国科学院动物研究所。 单眼樟蚕姬蜂Habronyx majorocellus Wang新种 雌蜂:前翅长15毫米,雄蜂:不详。 休红色。脸和唇基黄色。额带褐色。中胸盾片中叶、中胸侧板中下方至腹面、腹部第2节背板背部纵纹均为黑色。后足胫节的最端部带褐色。翅脉黑褐,翅痣黄褐,翅黄褐色透明。 体被浅色毛。头部宽于胸部;侧单眼明显大,与复眼相距很近;额部具皱褶,中央纵脊  相似文献   

4.
寄生稻纵卷叶螟的黄脸姬蜂新种描述(膜翅目:姬蜂科)   总被引:1,自引:0,他引:1  
稻纵卷叶螟黄脸姬蜂Chorinaeus facialis,新种 体长6.2—6.4毫米.前超长4.2—4.4毫米。 脸的宽度约为高度的1.2倍,密生刻点。唇基前缘微弱弧形,刻点比脸上的稍为稀疏些。眼颚距约为上颚基部宽度的1.2()至1.6()倍。上颚向末端稍细,其长度约为基部宽度的2倍,上端齿比下端齿长而且大。单眼与复眼之间的距离约与单眼直径相等。上颊侧面观稍隆拱,其宽度约与复眼横径相等。触角30—32节,鞭节第1节长度约为宽度  相似文献   

5.
嗜蛛姬蜂族Polysphinctini隶于姬蜂科Ichneumonidae瘤姬蜂亚科Pimplinae,全部为蜘蛛的寄生蜂。自1920年建立以来,我国已知13属130种。本文记述采自四川灌县和浙江西天目山的嗜蛛姬蜂族的一新属,长胫姬蜂属 Longitibia gen.nov.及属模:中华长胫姬蜂 Longitibia sinica sp.nov.。本新属特征是:唇基六边形,其外角有一小齿突,端部凹陷,端缘平截;中胸盾片光滑,后方中央具均匀细毛;胸腹侧脊长,上端接近于翅基下脊;并胸腹节前半部有不明显中纵脊,侧纵脊基半部不明显,端横脊缺;前中足腿节不肿大;后足特别细长,后足长为腹长的1.7倍,后足基节长为厚的2.8倍,后足胫节长为端宽的15倍;小脉在亚端部曲折。模式标本保存于浙江农业大学昆虫标本室。  相似文献   

6.
在整理1973年采集的蝇类标本中,发现莫蝇属一新种。现描记如下:(?)黑背莫蝇 Morellia(Morellia) nigridorsata, 新种 ♂:体长6毫米。 头:复眼祼;额最狭处稍宽于两后单眼外缘间距;间额绒黑色,间额宽约为一侧额的1.5倍;侧额亮黑色,侧额鬃发达;侧颜具银白色的粉被,侧颜中部宽相当于两后单眼的间距;颊棕黑色,具薄的银白色粉被;触角黑色,其第三节长为第二节的2倍,触角芒长羽状;下颚须黑色。  相似文献   

7.
坐腹姬蜂属Enizemun Foerster,1869,隶属于膜翅目姬蜂科蚜蝇姬蜂亚科,其主要特征为:中胸背板无盾纵沟;并胸腹节基区多少平坦;前翅通常有小翅室;腹柄节长宽几乎相等,背板有1对脊由基部伸达后缘;第2腹节背板基部有1对脊,第4腹节通常基部有折缘缝;雄虫触角中间鞭节有角下瘤。该属世界已报道约15种,中国记载2种:E.ornatum Gravenhorst,1829和E.formosense Uchida,1957。我们在整理标本时,发现该属1新种,现记述如下:  相似文献   

8.
报道寄生天牛的瘦角姬蜂属Ischnoceros Gravenhorst,1829 2新种:天牛瘦角姬蜂I.eutetraphae sp.nov.,寄生直脊天牛Eutetrapha sedecimpunctata(Motschulsky) ;松瘦角姬蜂I.laricinus sp.nov.,寄生云杉花墨天牛Monochamus saltuarius Gebler。编制了中国已知种检索表。天牛瘦角姬蜂,新种Ischnocero s eutetraphae sp.nov.(图1 ~3)新种与北海道瘦角姬蜂I.sapporensis Uchida,1928 ,相近,可通过下列特征区别:并胸腹节基区与中区由横脊分隔,侧突高为触角第2鞭节直径的1.5 ~1.6倍;腹部第2节背板具横细纹;翅基片褐色;中足基节大部分为红褐色;中足腿节红褐色或主要为红色。北海道瘦角姬蜂:并胸腹节基区与中区合并,无横脊分隔,侧突高约等于触角第2鞭节直径;腹部第2节背板具刻点;翅基片褐黑色;中足基节和中足腿节黑色。正模♀,辽宁新宾, 546m, 2005-08-20 ,盛茂领。副模: 1♀,辽宁新宾, 546m, 2005-06-09 ,盛茂领; 1 ♂,吉林伊通, 336m,2005-05-17 ,盛茂领。寄主:直脊天牛Eutetrapha sedecimpunctata(Motschulsky)。寄主植物:紫椴Tilia amurensis Rupr.。松瘦角姬蜂,新种Ischnoceros laricinus sp.nov.(图4 ~7)本种与三峡瘦角姬蜂I.sanxiaensis Wang,1997相近,可通过下列特征区别:并胸腹节第1侧区具清晰的斜纵皱;腹部第3 ~6节背板具横细纹;产卵器鞘长为后足胫节长的1.4~1.6倍;产卵器腹瓣端部,在脊的内侧具1粗糙区。三峡瘦角姬蜂:并胸腹节第1侧区具清晰的刻点;腹部第3 ~6节背板具稠密的刻点;产卵器鞘长约为后足胫节长的1.1倍;产卵器腹瓣端部无粗糙区。正模♀,吉林大兴沟, 586m, 2005-07-02 ,盛茂领。副模: 1♀,1 ♂,吉林大兴沟, 586m, 2005-07-01 ~03 ,盛茂领; 1 ♂,辽宁新宾, 546m, 2005-06-10 ,盛茂领; 1♀,3 ♂♂,辽宁本溪, 418m, 2006-06-20 ,盛茂领。寄主:云杉花墨天牛Monochamus saltuarius Gebler。寄主植物:兴安落叶松Larix gmelinii(Rupr.)Rupr.。瘦角姬蜂属中国已知种检索表1.额具稠密的横皱……………………………………………………2额无皱………………………………………………………………32.并胸腹节基部中央具1半圆形深凹,基区两侧的纵脊平行;产卵器腹瓣端部,在纵脊的内侧具1段粗糙的纵带;后足腿节黑色……………………………暗足瘦角姬蜂I.pedipullus Sheng并胸腹节基部中央无半圆形凹,基区两侧的纵脊向前强烈分散;产卵器腹瓣光滑,无粗糙的纵带;后足腿节红色赤足瘦角姬蜂I.rusticus(Geoffroy)…………………………………………3.腹部第3 ~6节背板具稠密的刻点三峡瘦角姬蜂I.sanxiaensisWang………………………………………………………………腹部第3 ~6节背板具稠密的细横线纹…………………………44.产卵器腹瓣端部,在纵脊的内侧具1段粗糙的纵带松瘦角姬蜂,新种I.laricinus sp.nov.……………………………………产卵器腹瓣光滑,无粗糙的纵带…………………………………55.腹部第1节背板的中纵脊至少伸抵气门;第2节背板具清晰的横线纹;基节具较大的红褐斑;中足腿节红褐色或主要为红色天牛瘦角姬蜂,新种I.eutetraphae sp.nov.………………………腹部第1节背板的中纵脊至多伸达基部至气门的一半;第2节背板无横线纹;基节黑色;中足腿节黑色………………………………………北海道瘦角姬蜂I.sapporensis Uchida  相似文献   

9.
王淑芳 《昆虫学报》1989,32(3):357-360
本文记述横断山地区犁姬蜂亚科Acaenitinae一新属和二新种。模式标本保存在中国科学院动物研究所。 粗点姬蜂属Asperpunctatus新属 模式种:黑粗点姬蜂Asperpunctatus nigrus新种 本属主要特征:头:胸部均具粗而密的刻点或刻纹。唇基端缘中央具弱的突起;下唇外露部分长为宽的0.7倍;上颚二端齿几乎等长;后头脊完整。盾纵沟明显,其长超过中胸盾片的中部;胸腹侧脊抵达前胸背板后缘中凹处之下;小盾片稍隆起;并胸腹节基部  相似文献   

10.
栉姬蜂属Banchus Fabricius 1798隶于栉姬蜂亚科Banchinae栉姬蜂族Banchini。主要特征是小盾片顶端具中刺或尖突;腹部第2和第3背板折缘宽约为该节长的0.7倍,有褶稍分开;下颚须5节,第4节端部稍扩大而扁平;唇基端缘中央具一缺刻;无胸腹侧脊;腹端部多少侧扁;产卵管很短。以寄生于裸露性的鳞翅目幼虫为主,包括斑蛾科、尺蛾科、天蛾科、舟蛾科、毒蛾科、波纹蛾科、夜蛾科、蛱蝶科,特别是在土中化蛹的夜蛾科幼虫;  相似文献   

11.
Aquaporins: water channel proteins of the cell membrane   总被引:37,自引:0,他引:37  
Aquaporins (AQP) are integral membrane proteins that serve as channels in the transfer of water, and in some cases, small solutes across the membrane. They are conserved in bacteria, plants, and animals. Structural analyses of the molecules have revealed the presence of a pore in the center of each aquaporin molecule. In mammalian cells, more than 10 isoforms (AQP0-AQP10) have been identified so far. They are differentially expressed in many types of cells and tissues in the body. AQP0 is abundant in the lens. AQP1 is found in the blood vessels, kidney proximal tubules, eye, and ear. AQP2 is expressed in the kidney collecting ducts, where it shuttles between the intracellular storage sites and the plasma membrane under the control of antidiuretic hormone (ADH). Mutations of AQP2 result in diabetes insipidus. AQP3 is present in the kidney collecting ducts, epidermis, urinary, respiratory, and digestive tracts. AQP3 in organs other than the kidney may be involved in the supply of water to them. AQP4 is present in the brain astrocytes, eye, ear, skeletal muscle, stomach parietal cells, and kidney collecting ducts. AQP5 is in the secretory cells such as salivary, lacrimal, and sweat glands. AQP5 is also expressed in the ear and eye. AQP6 is localized intracellular vesicles in the kidney collecting duct cells. AQP7 is expressed in the adipocytes, testis, and kidney. AQP8 is expressed in the kidney, testis, and liver. AQP9 is present in the liver and leukocytes. AQP10 is expressed in the intestine. The diverse and characteristic distribution of aquaporins in the body suggests their important and specific roles in each organ.  相似文献   

12.
The spined soldier bug, Podisus maculiventris, is a generalist predator of insects and has been used in biological control. However, information on the digestion of food in this insect is lacking. Therefore, we have studied the digestive system in P. maculiventris, and further characterized carbohydrases in the digestive tract. The midgut of all developmental stages was composed of anterior, median, and posterior regions. The volumes of the anterior midgut decreased and the median midgut increased in older instars and adults, suggesting a more important role of the median midgut in food digestion. However, carbohydrase activities were predominant in the anterior midgut. In comparing the specific activity of carbohydrases, α‐amylase activity was more in the salivary glands (with two distinct activity bands in zymograms), and glucosidase and galactosidase activities were more in the midgut. Salivary α‐amylases were detected in the prey hemolymph, demonstrating the role of these enzymes in extra‐oral digestion. However, the catalytic efficiency of midgut α‐amylase activity was approximately twofold more than that of the salivary gland enzymes, and was more efficient in digesting soluble starch than glycogen. Midgut α‐amylases were developmentally regulated, as one isoform was found in first instar compared to three isoforms in fifth instar nymphs. Starvation significantly affected carbohydrase activities in the midgut, and acarbose inhibited α‐amylases from both the salivary glands and midgut in vitro and in vivo. The structural diversity and developmental regulation of carbohydrases in the digestive system of P. maculiventris demonstrate the importance of these enzymes in extra‐oral and intra‐tract digestion, and may explain the capability of the hemipteran to utilize diverse food sources.  相似文献   

13.
It is noteworthy that in the rat the early postnatal life is marked by an activation of both the corticostimulating function of the adenohypophysis in neonates of both sexes and of the gonadostimulating function mainly in males. In order to specify if such neuroendocrine variations are temporally correlated with changes in the hypothalamic metabolism of neurotransmitters, the hypothalamic metabolism of serotonin (5 HT), norepinephrine (NE), and dopamine (DA) and the hypothalamic content of neuropeptide Y (NPY) have been investigated in newborn rats of both sexes, delivered at term by cesarean section, as well as changes in the activity of both the hypothalamo-pituitary adrenal axis (HPA) and the hypothalamo-pituitary gonadal axis (HPG). Experimental data suggested that 1) in males a rise in hypothalamic metabolism of 5 HT, NE and DA occurs during the first two hours after delivery, whereas in females, only the metabolism of NE increases. Moreover, the postnatal metabolism of NE was higher in females than in littermate males; 2) NPY content of the hypothalamus, which was at birth significantly higher in males than in females, dropped in the former but not in the latter; 3) in newborn males, an early surge of plasma testosterone occurs, suggesting postnatal activation of the HPG axis; on the other hand, in females, a late and slight increase in plasma estradiol is observed; 4) in early postnatal life, a sex-independent rise in plasma ACTH and adrenal and plasma corticosterone levels suggest a comparable activation of the HPA axis in newborns of both sexes. In conclusion, the early postnatal activation of the corticostimulating function in neonates of both sexes and that of the gonadostimulating function, mainly in males, could be temporally correlated with a rise in the hypothalamic metabolism of two neurotransmitters, 5 HT and NE, and of NPY content. According to our data, a sex-dependent metabolsim of neurotransmitters in the hypothalamus is already apparent in early postnatal life.  相似文献   

14.
Recent coral spawning observations in the central Red Sea show that most scleractinian species release their gametes in the spring, with a majority of species spawning in April. There is, however, a lack of reproductive data for several other coral species, as well as a general lack of data for other invertebrates. Here, we document the detailed timing of spawning for 13 scleractinian coral species, one sea anemone, and six echinoderms from an inshore reef off the coast of Thuwal, Saudi Arabia, in the spring between April and June 2014. Furthermore, inferred from the presence of mature gametes, we report the month of spawning for three additional coral species in the spring. Seven scleractinian coral species were inferred to release their gametes in a second reproductive season, in the autumn, between September and November. This is the first report of a second spawning season in the Arabian region. Biannual spawning has so far been reported on the Great Barrier Reef, in Western Australia, in Indonesia, in Malaysia, in Palau, in Thailand, in Taiwan, and in Western Samoa.  相似文献   

15.
苏春田  唐建生  梁彬 《生态学杂志》2012,31(8):2131-2136
采用雨量器、滤膜法、CO2气体监测管法、标准试片对湘西洛塔不同生态系统降雨量、泥沙量、土壤CO2浓度、溶蚀速度进行了研究。结果表明:森林生态系统降雨量高于灌丛生态系统,观测第一年高6.84mm,第二年高218.08mm,且时间趋向均匀;灌丛生态系统水土流失严重,其泥沙含量是森林生态系统的1.53倍,土壤侵蚀为强度,而森林生态系统为微度;不同深度土壤CO2浓度在森林和灌丛生态系统中具有相同的变化趋势,在春季、秋季、冬季随土层加深而增大,在夏季,随土层加深先减少后增大,但季节变化动态略有差异,森林生态系统不同深度、不同季节土壤CO2浓度均大于灌丛生态系统;从全年土壤CO2浓度对比来看,10、20、40cm处,森林生态系统分别是灌丛生态系统的1.66、1.59和1.90倍;不同深度上,溶蚀速度在森林和灌丛生态系统具有相同的变化趋势,15cm处均大于地面,从同一深度来看,森林生态系统溶蚀速度均大于灌丛生态系统,地面、15cm处溶蚀速度分别是灌丛生态系统的1.11倍、2.57倍,说明森林生态系统具有较好的岩溶效应。  相似文献   

16.
A role for ecdysteroids in the phase polymorphism of the desert locust   总被引:1,自引:0,他引:1  
Abstract. Locusts show density-dependent continuous phase polymorphism; they appear in two forms or phases, gregarious and solitary, and there is a continuous range of intermediates between the extreme phases. Although earlier studies showed that there are no major phase-dependent differences in the titres of ecdysteroid in the haemolymph of desert locusts, Schistocerca gregaria , recent studies showed some minor differences in the timing of the main peak of ecdysteroids. In crowded penultimate- and last-instar hoppers, peak titres were lower but longer-lasting, whereas in isolated hoppers they were higher but of shorter duration. The major component of the haemolymph peak of ecdysteroid was 20-hydroxyecdysone in both isolated and crowded hoppers, but differences were found in the relative amounts of two minor components (makisterone A-like compound and highly polar products). In S. gregaria adults, the regression of the prothoracic glands was irregular and subject to high individual variations, but phase-dependent differences in the rate of regression were significant, and the adult glands did not produce physiologically significant amounts of ecdysteroids. Peak titres of ecdysteroid in the haemolymph were higher in isolated than in crowded adults. Similar to larvae, adults of the solitary phase contain more ecdysone in the haemolymph than those of the gregarious phase. Moreover, the phase characteristic titres of ecdysteroid in the adult stage can be shifted from one phase to another phase in response to appropriate changes in density. In contrast, the maximum amount of ecdysteroids in both ovaries and eggs was significantly higher in the gregarious than in the solitary phase. The amounts, and to some extent the types of ecdysteroids, were the only difference between ovaries and eggs from solitary and gregarious locusts. In addition, in newly hatched larvae, the amount of ecdysteroid was more than five times higher in gregarious than in solitary phase.  相似文献   

17.
Brain-Specific Modulation of Kynurenic Acid Synthesis in the Rat   总被引:4,自引:1,他引:3  
Abstract: This study was designed to investigate modulatory mechanisms that control the synthesis of the neuroprotective endogenous excitatory amino acid receptor antagonist kynurenate. De novo kynurenate formation was examined in vitro using tissue slices from rat brain, liver, and kidney. In slices from adult cerebral cortex, veratridine, quisqualate, and l -α-aminoadipate decreased kynurenate synthesis substantially. Glucose removal or changes in the ionic milieu, too, influenced kynurenate formation significantly, suggesting that demands on cellular energy interfere with kynurenate production in the adult rat brain. The effects of quisqualate and l -α-aminoadipate were also observed in the immature brain, in the quinolinate-lesioned adult striatum, and, to a lesser extent, in peripheral organs. In contrast, the effect of veratridine was not seen in the lesioned brain or in kidney and liver tissue, indicating its dependency on intact neuron-glia interactions. Compared with the normal adult brain, ionic manipulations yielded qualitatively distinct results in the developing brain and in the periphery, but their effects remained unchanged in the lesioned striatum. Glucose deprivation was less consequential in the immature than in the adult brain and was entirely ineffective in the lesioned striatum and in the periphery. These results further link cellular, especially astrocytic, energy metabolism to kynurenate formation in the brain. More generally, the existence of brain-specific mechanisms for the regulation of kynurenate production is suggestive of a modulatory role of this metabolite in excitatory amino acid receptor function and dysfunction.  相似文献   

18.
Digestive enzyme distribution and activity in the digestive tracts of the rabbitfish, Siganus canaliculatus and the sea bass, Lates calcarifer were studied. Quantitative determinations of digestive enzymes in the guts of both fishes showed that they were capable of digesting carbohydrates and proteins in their diet. The carbohydrases, amylase, laminarinase, maltase, sucrase and trehalase were detected in the rabbitfish; their activities being mainly in the stomach, intestine and pyloriccaeca. Amylase, maltase, trehalase and chitinase activities were recorded in the gut of the sea bass, primarily in the intestine and the pyloriccaeca. Their activities were significantly lower than those in the rabbitfish. Proteases (pepsin, chymotrypsin, elastase, leucine aminopeptidase and trypsin) were found in both the rabbitfish and the sea bass. Pepsin activity however, was higher in the sea bass; while trypsin and chymotrypsin activities were higher in the rabbitfish. The activities of the various digestive enzymes in both fishes are discussed in relation to their feeding habits.  相似文献   

19.
To elucidate whether the extent of element accumulation in the arteries and cardiac valves with aging was different between different races, the authors investigated the accumulation of elements in the arteries and cardiac valves of the Thai with aging and the relationships among elements in the cardiac valves. After ordinary dissection at Chiang Mai University was finished, 16 arteries and 4 cardiac valves were resected and element contents were determined by inductively coupled plasma-atomic emission spectrometry. In the 16 arteries, the average content of calcium was the highest in the site of the abdominal aorta ramifying into the common iliac arteries, and it decreased in the order internal iliac, coronary, abdominal aorta, common iliac, external iliac, superior mesenteric, inferior mesenteric, thoracic aorta, brachial, radial, common carotid, subclavian, ulnar, axillary, renal, and internal thoracic arteries. The average contents of phosphorus and magnesium in respective arteries were parallel with the average contents of calcium, except for the coronary artery. In comparison with the arteries of the Japanese, the trend of calcium accumulation in the arteries of the Thai was almost similar to that in the arteries of the Japanese, except for the coronary artery and thoracic aorta. The calcium accumulation in the coronary artery was much higher in the Thai than in the Japanese, whereas that in the thoracic aorta was lower in the Thai than in the Japanese. Regarding elements in the cardiac valves, the calcium content increased remarkably in the seventies in the aortic valve and in the nineties in the pulmonary valve, but it hardly increased in both the mitral and tricuspid valves with aging. The average content of calcium was the highest in the aortic valve, and it decreased in the order pulmonary, tricuspid, and mitral valves. Regarding the relationship among elements in the aortic valves, it was found that there were extremely significant direct correlations among the contents of calcium, phosphorus, and magnesium, whereas there were significant direct correlations between zinc and either calcium or phosphorus contents. Although significant correlations were found between sulfur and the other element contents in the aortic valves of the Japanese, no significant correlations were found between them in the aortic valves of the Thai. In the mitral valves, extremely or very significant direct correlations were found among the contents of calcium, phosphorus, magnesium, and sulfur, with some exceptions that there were no significant correlations between phosphorus and either magnesium or sulfur contents. In addition, no significant correlation was found in the calcium content between the aortic valve and coronary artery in the same individuals.  相似文献   

20.
Arginase, ornithine carbamoyl transferase (OCT) and arginine deiminase activities were found in cell-free extracts of Nostoc PCC 73102, a free-living cyanobacterium originally isolated from the cycad Macrozamia. Addition of either arginine, ornithine or citrulline to the growth medium induced significant changes in their in vitro activities. Moreover, growth in darkness, compared to in light, induced higher in vitro activities. The in vitro activities of arginase and arginine deiminase, two catabolic enzymes primarily involved in the breakdown of arginine, increased substantially by a combination of growth in darkness and addition of either arginine, or ornithine, to the growth medium. The most significant effects on the in vitro OCT activities where observed in cells grown with the addition of ornithine. Cells grown in darkness exhibited about 6% of the in vivo nitrogenase activity observed in cells grown in light. However, addition of external carbon (glucose and fructose) to cells grown in darkness resulted in in vivo nitrogenase activity levels similar to, or even higher than, cells grown in light. Growth with high in vivo nitrogenase activity or in darkness with the addition of external carbon, resulted in repressed levels of in vitro arginase and arginine deiminase activities. It is suggested that nitrogen starvation induces a mobilization of the stored nitrogen, internal release of the amino compound arginine, and an induction of two catabolic enzymes arginase and arginine deiminase. A similar and even more pronunced induction can be observed by addition of external arginine to the growth medium.  相似文献   

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