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Cesariella graeca gen. sp. nov. is described to accommodate a new species of the Laboulbeniales (Fungi, Ascomycota) parasitic on the endogean ground beetles Reicheadella aetolica and R. bischoffi (Coleoptera, Carabidae) from Greece. Cesariella is distinguished from the allied genus Laboulbenia by the presence of two cells borne on the inner side of cell III, and by the presence of a conspicuous remnant of the spore apex protruding laterally near the base of the appendage.  相似文献   

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Despite the close similarities between retroviruses and the gypsy/Ty3 group of LTR-retrotransposons their host ranges are largely distinct: the retroviruses are found only in vertebrates, whereas the gypsy LTR-retrotransposons are almost exclusively restricted to invertebrates, plants and fungi. Here we report the amplification by PCR, and characterisation, of one of the first LTR-retrotransposons to be discovered in vertebrates - in several members of the piscine family Salmonidae. Phylogenetic analysis of this retroelement, termed easel, indicates that it is probably a phylogeneticaly basal member of the gypsy group of LTR-retrotransposons and occurs in some of the same species from which retroviruses have previously been isolated. Thus some members of the Salmonidae are the first organisms known to harbour both retroviral branch elements and the gypsy LTR-retrotransposon branch elements. This creates an overlap in the host ranges of the two retroelement families.  相似文献   

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Introduction of a Micrococcus plasmid in Escherichia coli   总被引:1,自引:0,他引:1  
A 6-MDa plasmid (pMQV10), carrying cholesterol hydroxylase and streptomycin-resistance genes, from a gram-positive strain of Micrococcus sps., (RJ6) has been successfully transformed in gram-negative Escherichia coli K12 C600. pMQV10 is maintained stably and expresses its drug resistance in the new host.  相似文献   

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We have characterized a mitochondrial gene in Oenothera, designated orf454, capable of encoding a component of the cytochrome c biogenesis system. This open reading frame is interrupted by an intron of 941 nucleotides showing high similarity to a group II intron residing in the rpl2 gene. RNA editing, which is observed at 18 cytidine positions within the orf454 reading frame, improves the similarity to protein-coding sequences in bacteria and higher plants and removes the last 16 amino acids. orf454 also shows high sequence similarity to two overlapping reading frames (orf169 and orf322) of Marchantia mitochondria. These ORFs belong to an operon-like cluster of genes in the liverwort that is not conserved in Oenothera mitochondria. However, in bacteria these reading frames are organized like the Marchantia gene cluster. It has been shown by genetical analysis in Rhodobacter capsulatus that these genes are essential for cytochrome c biogenesis. Genes of bacterial operons — ccl1 in Rhodobacter and yejR and nrfE in Escherichia coli — show high sequence similarity to the mitochondrial reading frames orf577 and orf454 of Oenothera. orf454, which we describe here, is homologous to the C-terminal region of these bacterial genes, while the previously described orf577 is homologous to the N-terminal region.  相似文献   

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We examined longevity, fecundity, and oviposition strategies ofEucelatoria bryani Sabrosky (Diptera: Tachinidae), a gregarious endoparasitoid ofHelicoverpa zea (Boddie) andHeliothis virescens (F.) (Lepidoptera: Noctuidae). Longevity of adult femaleE. bryani was not related to body size. In contrast to longevity, largerE. bryani females had greater potential fecundity than smaller females, as determined by the number of embryonated eggs present in the common oviduct. However, female parasitoid size did not affect primary clutch size (number of eggs deposited in a host). Because embryos in eggs located in the ovisac were larger than those located elsewhere in the common oviduct, maximum primary clutch size may be physiologically limited by the number of fully mature eggs a female has available at one time.E. bryani females adjusted primary clutch size in response to host size, for bothH. zea andH. virescens. This adjustment appears to be adaptive because females did not overexploit hosts by depositing more larvae than a host could support. Adult emergence was not related to host size. Although host weight positively influencedE. bryani progeny weight, increases in progeny size with host size were counterbalanced by increases in primary clutch size with host size.  相似文献   

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[背景] 在陕西省的毛泡桐腐木桩上观察和采集到一株绒毛状真菌子实体,编号为HMNWAFU-CF-HS002。[目的] 为了确定该菌的分类地位,对其进行形态观察及分子鉴定。[方法] 获取宏观彩色图像并对显微结构进行测量、统计和绘图。此外,用PDA培养基分离纯化该菌的培养物,并结合最大似然法、最大简约法和贝叶斯法进行rDNA ITS分子系统学研究。[结果] HMNWAFU-CF-HS002的形态特征与Punctularia atropurpurascens高度相似。系统发育分析将HMNWAFU-CF-HS002聚在P.atropurpurascens的单系分支中。[结论] 结合形态学特征与系统发育结果,HMNWAFU-CF-HS002被鉴定紫黑点壳菌(Punctularia atropurpurascens),为中国的新记录种。此外,毛泡桐为其新记录寄主。至此,Punctularia属下的3个种,均在中国有分布记录。  相似文献   

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In this study we used tightly-coupled mitochondria from Yarrowia lipolytica and Dipodascus (Endomyces) magnusii yeasts, possessing a respiratory chain with the usual three points of energy conservation. High-amplitude swelling and collapse of the membrane potential were used as parameters for demonstrating induction of the mitochondrial permeability transition due to opening of a pore (mPTP). Mitochondria from Y. lipolytica, lacking a natural mitochondrial Ca2+ uptake pathway, and from D. magnusii, harboring a high-capacitive, regulated mitochondrial Ca2+ transport system (Bazhenova et al. J Biol Chem 273:4372–4377, 1998a; Bazhenova et al. Biochim Biophys Acta 1371:96–100, 1998b; Deryabina and Zvyagilskaya Biochemistry (Moscow) 65:1352–1356, 2000; Deryabina et al. J Biol Chem 276:47801–47806, 2001) were very resistant to Ca2+ overload. However, exposure of yeast mitochondria to 50–100 μM Ca2+ in the presence of the Ca2+ ionophore ETH129 induced collapse of the membrane potential, possibly due to activation of the fatty acid-dependent Ca2+/nH+-antiporter, with no classical mPTP induction. The absence of response in yeast mitochondria was not simply due to structural limitations, since large-amplitude swelling occurred in the presence of alamethicin, a hydrophobic, helical peptide, forming voltage-sensitive ion channels in lipid membranes. Ca2+- ETH129-induced activation of the Ca2+/H+-antiport system was inhibited and prevented by bovine serum albumin, and partially by inorganic phosphate and ATP. We subjected yeast mitochondria to other conditions known to induce the permeability transition in animal mitochondria, i.e., Ca2+ overload (in the presence of ETH129) combined with palmitic acid (Mironova et al. J Bioenerg Biomembr 33:319–331, 2001; Sultan and Sokolove Arch Biochem Biophys 386:37–51, 2001), SH-reagents, carboxyatractyloside (an inhibitor of the ADP/ATP translocator), depletion of intramitochondrial adenine nucleotide pools, deenergization of mitochondria, and shifting to acidic pH values in the presence of high phosphate concentrations. None of the above-mentioned substances or conditions induced a mPTP-like pore. It is thus evident that the permeability transition in yeast mitochondria is not coupled with Ca2+ uptake and is differently regulated compared to the mPTP of animal mitochondria.  相似文献   

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Geocoris punctipes (Say), a predaceous lygaeid not previously docmented as a whitefly predator, was tested in the laboratory as a natural enemy of the sweet potato whitefly, Bemisia tabaci (Genn.). Its stalking behavior with whiteflies as prey was similar to that observed with aphids. A previously unobserved behavior was noted that involves the predators using salivary secretions to fasten the wings of prey to various surfaces, allowing labial probing and feeding. Prey consumption as a function of prey number appeared to follow the pattern of the Holling type II functional response. Handling time per prey item ranged from about 180 to 240 seconds. No changes were observed in handling time devoted to earlier versus later catches. Nutritional quality of whiteflies was measured using crude protein, lipids and carbohydrates as criteria. Performance, in terms of predator behavior, total daily handling time, functional response, energy budget and nutritional quality all support the hypothesis that G. punctipes is a promising candidate for biological control of sweet potato whiteflies.  相似文献   

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Staphylococcus aureus plasmid pC194 carries three sequences closely related to a consensus sequence defined previously by analysis of different genetic elements which replicate autonomously in yeast Saccharomyces cerevisiae. Two of these enable the plasmid to replicate in yeast, the third does not. A new consensus sequence A/T T T T A T R T T T, 1 bp shorter than the previous one, can be deduced from our results. Replacement of the T with G at the position 9 of the sequence abolishes its activity. The presence of the two active sequences on pC194 genome can be explained by the A + T-rich base composition of the plasmid.  相似文献   

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A new genus, Cystobasidiopsis, and a new species, Cystobasidiopsis nirenbergiae, are described for a fungus isolated from an arable loess soil in Ahlum near Braunschweig, Niedersachsen, Germany. An integrated analysis of morphological, ecological, ultrastructural and molecular data indicates that the new species belongs to the Chionosphaeraceae within the Agaricostilbales. Relevant characteristics of the new species are discussed and compared with those of related taxa.  相似文献   

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Golovinomyces is a strictly herb-parasitic genus in the Erysiphaceae. Host–parasite co-speciation was reported recently between the genus Golovinomyces and Asteraceae from molecular phylogenetic analyses. The Asteraceae originated in South America and latterly expanded their geographic distribution into the Northern Hemisphere. If the co-speciation between Golovinomyces and Asteraceae originated in South America, the geographic origin of Golovinomyces could be assumed to be South America. To address this question, Golovinomyces species from hosts of the tribe Mutisieae, an asteraceous tribe endemic to South America, were collected and the ITS and 28S rDNA regions sequenced. Results indicate that Oidium mutisiae and Golovinomyces leuceriae isolated from the Mutisieae do not belong at the base of the Golovinomyces tree. Instead, they are situated separately within two different clades of Golovinomyces isolates from the Northern Hemisphere. Therefore, the tribe Mutisieae is not the most early host of Golovinomyces. Present results suggest that Golovinomyces originated in the Northern Hemisphere, and not in South America. The new species Oidium reginae for the previous O. mutisiae on Mutisia decurrens is proposed.  相似文献   

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Ohne Zusammenfassung  相似文献   

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Molecular phylogenetic and comparative morphological studies provide evidence for the recognition of a new family, Chorioactidaceae, in the Pezizales. Four genera are placed in the family: Chorioactis, Desmazierella, Neournula, and Wolfina. Based on parsimony, likelihood, and Bayesian analyses of LSU, SSU, and RPB2 sequence data, Chorioactidaceae represents a sister clade to the Sarcosomataceae, to which some of these taxa were previously referred. Morphologically these genera are similar in pigmentation, excipular construction, and asci, which mostly have terminal opercula and rounded, sometimes forked, bases without croziers. Ascospores have cyanophilic walls or cyanophilic surface ornamentation in the form of ridges or warts. So far as is known the ascospores and the cells of the paraphyses of all species are multinucleate. The six species recognized in these four genera all have limited geographical distributions in the northern hemisphere.  相似文献   

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Summary The mutation prt1-1 with a thermosensitive block in initiation of protein synthesis was introduced into a rad3 strain to study the effect of inhibition of protein synthesis on liquid holding recovery (LHR) from the lethal effects of diepoxybutane (DEB). Liquid holding of the prt1-1rad3 strain under restrictive conditions did not decrease the level of recovery as compared with the permissive temperature. Post-incubation of cells in growth medium under permissive conditions prior to LH resulted in the loss of capacity for LHR, while cells post-incubated under restrictive conditions were fully capable of LHR. The results are interpreted as indicating that protein synthesis during LH is not required for the increase in survival and that the occurrence of protein synthesis prior to liquid holding abolishes the capacity for LHR.  相似文献   

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A plasmid, pUVABC-2, was constructed that encodes functional uvrA, B, and C genes of Escherichia coli. This plasmid also contains the gpt and ampr genes for positive selection in either bacterial or mammalian systems. Each of the uvrA, B, C, and gpt genes is located between SV40 initiation and termination signals and retains the original bacterial promoters. This recombinant vector conferred a wild-type UV resistance phenotype to uvrA-, B-, and C- strains of E. coli. The results indicate that each of the uvr genes contained in pUVABC-2 function in E. coli. The plasmid is a potential biological probe for DNA repair in mammalian cells.  相似文献   

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