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1.
甲基营养菌的研究进展   总被引:2,自引:0,他引:2  
甲基营养菌是一类能够利用一碳化合物作为唯一碳源和能源的微生物,它们在自然界分布广泛.研究表明,甲基营养菌能够直接利用一碳化合物,将其转化成自身代谢的一碳单位,并为生物体提供能源和碳骨架,这组成了一碳代谢的主要部分,它是一种新的代谢体系,可以作为一种新的代谢模式来研究生物代谢和生物进化.本文结合本实验室Methylobacterium sp.MB200的研究情况,主要从分类学、代谢途径、基因组学和应用等方面,论述了甲基营养菌的研究进展.  相似文献   

2.
甲基营养菌(Methylotrophs)的代谢   总被引:1,自引:0,他引:1  
甲基营养菌是能够代谢含有甲基(CH_3~-)或者能代谢二个或多个甲基互相连接(不是—C—C直接连接的)的1—碳化合物,并以这些1—碳化合物作为能源和碳源进行生长的一类微生物。这些1—碳化合物主要有:甲烷、二甲醚(CH_3—O—CH_3)、甲醇、甲醛、甲酸和甲基胺等。迄今为止除了近年来分离的几株真核酵母能利用甲烷甲醇为生长基质的外、只有原核细菌具有这种同化—碳的能力。  相似文献   

3.
栓皮栎林下主要丝状真菌的分解能力   总被引:7,自引:0,他引:7  
利用纯培养试验方法 ,研究了栓皮栎林下凋落物中可培养的 10种主要丝状真菌对群落建群种栓皮栎 (Quercus variabilis)和林下主要伴生树种山胡椒 (L indera glauca)叶片的分解能力。结果表明 :在 10种真菌的作用下 ,9周时间内 ,栓皮栎叶片的平均失重率是山胡椒叶片的 2倍 ;两种叶片前期 (前 5周 )失重率均显著高于后期 (后 4周 )。分析结果显示叶片失重率与叶片初始木质素 /氮素、碳素 /氮素的比值成反比。根据每个菌株对每种叶片在前期和后期的重量失重率 (W)、木质素失重率 / W和木质素失重率 /全碳化合物失重率的值的相互关系 ,分解菌可以分为如下类型 :Trichoderma sp.1和 Cladosporium berbarum是对全碳化合物有一定利用能力的分解菌 ;Trichoderma sp.2、 Aspergillus fumigatus、Alternaria sp.、Penicillium sp.2对木质素、全碳化合物都有分解能力但偏向全碳化合物的分解 ,是分解能力相对较强的真菌 ;Chaetomium bostrychodes、Pestalotia sp.对木质素、全碳化合物都有分解能力并偏向木质素的分解 ,但分解能力较弱 ;Aspergillus niger、Penicillium sp.1只在试验分解前期内对木质素、全碳化合物都有一定的分解能力。不同真菌对叶片的分解能力不同 ,即使是同属真菌之间也有显著的差异  相似文献   

4.
碳碳相关谱测定Oplopanone的结构   总被引:4,自引:2,他引:2  
从四川产泽泻(Alisma orientalis Juzep.)中分离出一个倍半萜成分,经碳碳相关等核磁谱测定为Oplopanone。该成分为首次从泽泻科中分得,利用碳碳相关信息对该成分的碳谱进行了全归属,并讨论了该化合物的生物合成途径。  相似文献   

5.
有机碳化合物对湛江等鞭金藻生长的影响   总被引:1,自引:0,他引:1  
为了探讨有机碳化合物对湛江等鞭金藻的营养效应,实验设置了在f/2培养基中添加葡萄糖、乙酸钠、半乳糖、甘油、乙醇、柠檬酸钠和甘氨酸等7种有机碳化合物的处理,测定了湛江等鞭金藻(Isochrysis zhanjiangensis)的生长情况。结果表明,参试的7种有机碳化合物中,甘氨酸对湛江等鞭金藻细胞生长的促进作用最明显,而乙醇对藻细胞生长的促进效果不明显,其他5种均有不同程度的促进作用。7种有机碳对湛江等鞭金藻胞内蛋白质含量和总脂的积累量具有一定差异性影响。0.5~10g·L-1的葡萄糖、乙酸钠均可提高胞内蛋白质和总脂的含量。半乳糖对总脂积累量的影响不明显。  相似文献   

6.
高等植物中一碳化合物代谢研究进展   总被引:1,自引:0,他引:1  
高等植物中一碳(C1)化合物的代谢主要包括甲醇代谢、甲醛代谢和甲酸代谢等,它们是高等植物一碳单位代谢的重要组成部分.由于C1化合物的代谢机制复杂、代谢规模非常小、参与代谢反应的酶和中间产物的含量低且不稳定等特点,相关研究报道很有限.现代生化和分子遗传学方法的综合使用使得人们对参与植物中C1化合物代谢的酶和基因有了一定程度的了解,该文主要综述了近年来有关高等植物中内源和外源C1化合物甲醇、甲醛和甲酸的来源和代谢途径方面的研究进展,并提出了该研究领域目前存在的问题和今后的研究方向.  相似文献   

7.
一碳化合物作为糖类的廉价替代底物在工业生物技术中具有广泛的应用前景。传统途径中由一碳化合物或糖类生产乙酰辅酶A衍生产品时会有1/3的碳损失,导致产品得率较低,因此找到没有碳损失的新途径非常重要。基于MetaCyc数据库的代谢反应集和通量平衡分析的途径分析方法,计算得到一条由一碳化合物甲醛生成乙酰辅酶A衍生产品的新途径,该途径不仅无碳损失,并且无能量(ATP)和还原力消耗。为了验证途径的可行性,筛选途径相关酶,纯化后进行体外实验,通过乙酸的产量来间接表征途径的运行情况。结果发现:乙酸的生成浓度会随着体系初始甲醛加入量的增加而增加,在一定条件下,乙酸的总碳摩尔得率可以达到90%,超过了传统路径的最大理论得率67%。  相似文献   

8.
珠子草化学成分的研究   总被引:1,自引:0,他引:1  
利用大孔树脂吸附和多种柱层析方法,从珠子草中分离得到5个化合物,根据理化数据和波谱学等方法鉴定为柯里拉京(1)、芦丁(2)、isobubbialine(3)、丁二酸(4)和没食子酸(5)。根据2D-NMR修正了化合物3的部分碳信号归属,归属了化合物1的碳氢谱数据。  相似文献   

9.
木质纤维素是制备生物液体燃料和化工品的理想原料。介绍了近年来木质纤维素通过水热解聚途径制备能源化工平台化合物和平台化合物碳链增长途径的研究进展,重点讨论了制备5-羟甲基糠醛(HMF)平台化合物的途径、介质、催化剂,分析了水热解聚技术的优势及困难,并对该领域的研究进行了展望。  相似文献   

10.
[目的]探究橘小实蝇Bactrocera dorsalis和番石榴实蝇Bactrocera correcta卵提取物对2种实蝇雌虫行为的影响,以及2种实蝇卵表面化合物的差异,为2种实蝇的化学生态防治提供理论依据.[方法]利用Y型嗅觉仪测定了橘小实蝇交配雌虫和番石榴实蝇交配雌虫对卵表提取物的行为反应,并利用EthoVision XT软件分析雌虫在Y管内的运动轨迹;利用气相色谱-质谱联用仪(GC-MS)鉴定分析橘小实蝇卵和番石榴实蝇卵的化合物成分,并利用标准曲线法测定了各组分的含量.[结果]橘小实蝇卵提取物对橘小实蝇交配雌虫具有显著引诱作用(x2=9.383,P=-0.002),对番石榴实蝇交配雌虫具有显著驱避作用(x2=6.737,P=0.009),番石榴实蝇卵提取物对番石榴实蝇交配雌虫(x2=4.235,P=0.040)和橘小实蝇交配雌虫都具有引诱作用(x2=5.818,P=0.016).从橘小实蝇卵表提取物中共鉴定出11种化合物,分别是茴香脑、十五烷、十二烷酸、十二酸乙酯、(Z)-11-十四碳烯酸、十四烷酸、十四酸乙酯、(E)-9-十六碳烯酸乙酯、十六烷酸、十八碳烯酸、(Z)-9-十八碳烯酸乙酯.从番石榴实蝇卵表提取物中仅鉴定出7种化合物,而且这7种化合物在橘小实蝇的卵提取物中都存在.仅存在于橘小实蝇卵表的4种化合物是茴香脑、十二烷酸、十二酸乙酯、(Z)-11-十四碳烯酸.在2种实蝇卵提取物的相同成分中,十四烷酸、(E)-9-十六碳烯酸乙酯、十六烷酸在橘小实蝇卵表的含量显著高于番石榴实蝇.[结论]番石榴实蝇具有通过卵表化合物识别同种卵和异种卵的能力,2种实蝇的卵表化合物具有明显的差异.  相似文献   

11.
12.
The present paper is part of taxonomic study on Chinese Phyllanthoideae. Included in it are two new varieties, Leptopus esquirolii var. villosus and Drypetes hainanensis var. longistipitata, one new combination, Glochidion triandrum var. siamense, and seven new records in China: Drypetes salicifolia, D. hoaensis. Actephila subsessilis, Glochidion khasicum, G. nubigennum, Bridelia spiosa and B. poilanei. In addition, seventeen taxon names are newly reduced: Liodendron formosanum = Drypetes formosana, Liodendron matsumurae = Drypetes matsumurae, D. longipes = D. indica, Antidesma paxii = A. acidum, A. hiiranense, A. filipes and A. pentandrum var. hiiranense = A. japonicum, A. calvescens = A. montanum, A. microphyllum = A. venosum, Breynia stipitata var. formosana and B. jormosana = B. vitis-idaea, Glochidion zeylanicum var. tomentosum = G. hirsutum, G. rubidulum = G. thomsonii, G. acuminatum = G. triandrum, G. fagifolium and Phyllanthus fagifolius = Glochidion sphaerogynum, Bridelia penangiena = B. insulana, B. henryana = B. tomentosa. All the types are kept in SCBl and PE.  相似文献   

13.
At one spectrum extreme, Astrobiology conjectures that for exoplanets with Goldilocks conditions, terrestrial-like life is inevitable. Moreover, it is envisaged that via panspermia, terrestrial-like life and its precursors are transferred among galaxies, stars, and within solar systems via transiting comets, asteroids, and planetoids. In addition, expelled stars, which have solar systems, it is inferred, transfer life as well. However, at the other extreme, we propose a paradigm shift that on some planets, subject to non- Goldilocks conditions, metal machine life could arise, ab initio, and evolve viruses, intelligence, and civilizations, conjointly. Accordingly, intelligent mechanized civilizations could readily and efficiently commence space exploration. Furthermore, as a counter paradigm shift, such civilizations could experiment and produce non-metallic life, based on carbon and other non-metal elements, under suitable conditions, related to Goldilocks life. Even a single example of validated interstellar or intergalactic communication received on the Earth would support the existence of life elsewhere. However, the communication platform should not be restricted to electromagnetic radiation. Other platforms should be included as well - one such example, which would require sophisticated technology, is neutrino communication. This is the case for any advanced civilization, be it metal-machine based, biological-based, and carbon-based. In sum, civilizations based on machine life, would be highly productive due to the longevity and hardiness of machine life. However, significant caveats are raised in this brief report, because possibly dissimilar psychologies and intelligence may lead to conflicts between metal machine life and biological life, inter-paradigm conflict.  相似文献   

14.
The phylogeny of groups within Gobioidei is examined with molecular sequence data. Gobioidei is a speciose, morphologically diverse group of teleost fishes, most of which are small, benthic, and marine. Efforts to hypothesize relationships among the gobioid groups have been hampered by the prevalence of reductive evolution among goby species; such reduction can make identification of informative morphological characters particularly difficult. Gobies have been variously grouped into two to nine families, several with included subfamilies, but most existing taxonomies are not phylogenetic and few cladistic hypotheses of relationships among goby groups have been advanced. In this study, representatives of eight of the nine gobioid familes (Eleotridae, Odontobutidae, Xenisthmidae, Gobiidae, Kraemeriidae, Schindleriidae, Microdesmidae, and Ptereleotridae), selected to sample broadly from the range of goby diversity, were examined. Complete sequence from the mitochondrial ND1, ND2, and COI genes (3573 bp) was used in a cladistic parsimony analysis to hypothesize relationships among the gobioid groups. A single most parsimonious topology was obtained, with decay indices indicating strong support for most nodes. Major phylogenetic conclusions include that Xenisthmidae is part of Eleotridae, and Eleotridae is paraphyletic with respect to a clade composed of Gobiidae, Microdesmidae, Ptereleotridae, Kraemeriidae, and Schindleriidae. Within this five-family clade, two clades are recovered. One includes Gobionellinae, which is paraphyletic with respect to Kraemeriidae, Sicydiinae, Oxudercinae, and Amblyopinae. The other contains Gobiinae, also paraphyletic, and including Microdesmidae, Ptereleotridae, and Schindleriidae. Previous morphological evidence for goby groupings is discussed; the phylogenetic hypothesis indicates that the morphological reduction observed in many goby species has been derived several times independently.  相似文献   

15.
16.
The present study was performed to investigate the infection status with helminth in a group of feral cats in Korea. More than 29 helminth species including adults or eggs were detected in visceral and fecal samples of the examined cats. Among these were a host of nematodes, including toxocarids, Ancylostoma sp. and the larva of Anisakis simplex; trematodes, including Clonorchis sinensis, Paragonimus westermani, Eurytrema pancreaticum, Pharyngostomum cordatum, Metagonimus spp., Heterophyes nocens, Pygidiopsis summa, Heterophyopsis continua, Stictodora fuscata, Stictodora lari, Acanthotrema felis, Stellantchasmus falcatus, Centrocestus armatus, Procerovum varium, Cryptocotyle sp., Echinostoma revolutum, Echinostoma hortense, Echinochasmus japonicus, Stephanoprora sp., Plagiorchis muris, Neodiplostomum sp. and diplostomulum. We also detected a variety of cestodes, including Spirometra erinacei, Taenia taeniaeformis and unidentified species of tapeworm. We also found examples of the acanthocephalan, Bolbosoma sp. In our assessment of the stools, we detected at least 12 species of helminth eggs. These findings confirmed that feral cats in Korea are infected with a variety of helminth parasite species. Furthermore, among the helminths detected, E. pancreaticum, S. fuscata, S. lari, A. felis, S. falcatus, C. armatus, P. varium, Cryptocotyle sp., E. revolutum, E. japonicus, Stephanoprora sp., P. muris, Neodiplostomum sp. and Bolbosoma sp. represent helminth fauna which have not been reported previously in feral cats in the Republic of Korea.  相似文献   

17.
首次系统研究并报道了中国海南省分布的金小蜂,记录15属19种,编制了属种检索表。同时初步探讨了海南省与洲、非洲之间在金小蜂分布上的关系。  相似文献   

18.
This study describes a method for predicting and classifying oxygen-binding pro- teins. Firstly, support vector machine (SVM) modules were developed using amino acid composition and dipeptide composition for predicting oxygen-binding pro- teins, and achieved maximum accuracy of 85.5% and 87.8%, respectively. Sec- ondly, an SVM module was developed based on amino acid composition, classify- ing the predicted oxygen-binding proteins into six classes with accuracy of 95.8%, 97.5%, 97.5%, 96.9%, 99.4%, and 96.0% for erythrocruorin, hemerythrin, hemo- cyanin, hemoglobin, leghemoglobin, and myoglobin proteins, respectively. Finally, an SVM module was developed using dipeptide composition for classifying the oxygen-binding proteins, and achieved maximum accuracy of 96.1%, 98.7%, 98.7%, 85.6%, 99.6%, and 93.3% for the above six classes, respectively. All modules were trained and tested by five-fold cross validation. Based on the above approach, a web server Oxypred was developed for predicting and classifying oxygen-binding proteins(available from http://www.imtech.res.in/raghava/oxypred/).  相似文献   

19.
李志强  LI Hou-Hun 《昆虫学报》2005,48(2):247-261
基于对世界柽麦蛾属昆虫外部形态和外生殖器的形态学研究,选择了66个性状演变系列,通过PAUP*4b10软件对柽麦蛾属51种昆虫进行了支序系统学分析。分析结果认为heluanensis种团并不是一个单系群,柽麦蛾属被重新作了7个种团的划分。在支序系统学分析的基础上,柽麦蛾属昆虫的14个地理分布区域等级关系被重建,显示出古地中海地区复杂的历史,同时说明在该属分布格局中扩散事件客观存在。  相似文献   

20.
Mating systems are reported for taxa of polypores and agarics considered related. Taxa areDictyopanus pusillus, Favolus alveolaris, F. tenuiculus, Lentinus bertierii, L. crinitis, L. punctaticeps, L. strigellus, L. strigosus, L. suavissimus, Pleurotus australis, P. levis, P. tuberregium, Polyporus ciliatus, P. elegans, P. squamosus, andP. varius. All are tetrapolar exceptP. elegans.  相似文献   

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