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1.
Identification of Culturable Oligotrophic Bacteria within Naturally Occurring Bacterioplankton Communities of the Ligurian Sea by 16S rRNA Sequencing and Probing 总被引:10,自引:0,他引:10
L. Giuliano M. De Domenico E. De Domenico M.G. Höfle M.M. Yakimov 《Microbial ecology》1999,37(2):77-85
Abstract
Typical marine bacteria (i.e., obligately oligotrophic) that were numerically dominant members of naturally occurring marine
communities were identified by cloning and sequencing the amplified 16S rRNA genes obtained from dilution cultures of the
original samples. The data reported here refer to two different habitats of a marine pelagic environment (28 miles offshore,
in the northwestern Mediterranean Sea). The samples were taken from the water column at two representative layers, i.e., the
30-m depth, corresponding to the chlorophyll maximum layer, and the 1800-m depth, representative of a deep, oligotrophic environment.
Three major lineages were found in the 16S rDNA clone libraries prepared from the two samples, two of which could be assigned
to the Vibrio and the Rhodobacter groups. The third lineage was a distant relative of the genus Flavobacterium, but it was not closely related to any marine isolate. Six oligonucleotide probes, either complementary to the conserved sequence
domains or selectively hybridizing to the clone sequences, were designed for use as hybridization group-specific and strain-specific
probes. A single-mismatch discrimination between certain probes and nontarget sequences was demonstrated by detecting the
probes' specificity at different hybridization and washing conditions. The screening of the clone libraries with the obtained
probes revealed that neither the 30-m sample higher dilution nor the 1800-m one were pure cultures. While some representatives
of the Vibrio group were found in both the surface and the deep sample, the members of the Flavobacterium and Rhodobacter lineages were detected only in the deep and the euphotic layers, respectively. We suggest an approach for analyzing autochthonous
marine bacteria able to grow in unamended seawater.
Received: 19 May 1998; Accepted: 29 October 1998 相似文献
2.
Francesca Passaretta Domenico Bosco Lucia Centurione Maria Antonietta Centurione Fabio Marongiu Roberta Di Pietro 《Journal of cellular and molecular medicine》2020,24(7):4350-4355
Human Amniotic Epithelial Cells (hAEC) isolated from term placenta are a promising source for regenerative medicine. However, it has long been debated whether the hAEC population consists of heterogeneous or homogeneous cells. In a previous study, we investigated the characteristics of hAEC isolated from four different regions of the amniotic membrane finding significant heterogeneity. The aim of this study was to evaluate the hepatic differentiation capability of hAEC isolated from these four regions. Human term placentae were collected after caesarean section and hAEC were isolated from four regions of the amniotic membrane (R1-R4, according to their relative distance from the umbilical cord) and treated in hepatic differentiation conditions for 14 days. hAEC-derived hepatocyte-like cells showed marked differences in the expression of hepatic markers: R4 showed higher levels of Albumin and Hepatocyte Nuclear Factor (HNF) 4α whereas R1 expressed higher Cytochrome P450 enzymes, both at the gene and protein level. These preliminary results suggest that hAEC isolated from R1 and R4 of the amniotic membrane are more prone to hepatic differentiation. Therefore, the use of hAEC from a specific region of the amniotic membrane should be taken into consideration as it could have an impact on the outcome of therapeutic applications. 相似文献
3.
4.
Giorgio Di Marco Nicola D'Ambrosio Maria T. Giardi Angelo Massacci Domenico Tricoli 《Photosynthesis research》1989,21(2):117-122
We investigated several photosynthetic parameters of a virescent mutant of durum wheat and of its wild-type. Electron transport rate to ferricyanide was the same in the two genotypes when expressed on leaf area basis while O2 evolution of the leaf tissue in saturating light and CO2 was slightly higher in the yellow genotype. RuBPCase was also slightly higher. Quantum yield per absorbed light was similar in the two genotypes. P700 and Cyt f were less concentrated in the mutant while PS II was only marginally lower. The light response curve of CO2 assimilation indicated higher level of photosynthesis of the mutant in high light, which corresponded to a lower non-photochemical quenching compared to the wild-type. It is concluded that the reaction centres, cyt f and chlorophyll are not limiting factors of electron transport in wheat seedlings and that electron transport capacity is in excess with respect to that needed for driving photosynthesis. Since the differences in photosynthesis reflect differences in RuBPCase activity, it is suggested that this enzyme limits photosynthesis in wheat seedlings also at high light intensities.Abbreviations cyt f
cytochrome f
- chl
chlorophyll
- PS II
photosystem II
- Pnmax
maximum photosynthesis
- RuBCase
Ribulose, 1-5,bisphosphate carboxylase 相似文献
5.
6.
In total, 73 strains of methanogen isolates from our laboratory and 6 from culture collections were examined for the presence of plasmid DNA. Five strains were found to contain detectable plasmids. Multiple plasmids were found in two isolates, while three strains contained only one plasmid each. A physical map of the plasmid pT3 was constructed by use of six different restriction endonucleases. All sites were aligned with a single BgII site, and the position of the restriction sites was determined by double or sequential digestion of the plasmid DNA. 相似文献
7.
8.
Carmelo B. Bruni M. Stella Carlomagno Silvestro Formisano Giovanni Paolella 《Molecular & general genetics : MGG》1986,203(3):389-396
Summary A detailed comparative analysis of the Escherichia coli and Salmonella typhimurium hisIE and hisD gene products and the functionally equivalent, single, HIS4 gene product of Saccharomyces cerevisiae permitted several insights concerning the relationship between these genes. Our analysis supports the idea that HIS4 results from the fusion of hisIE and hisD. The comparison permitted a more precise definition of the functional domains of hisI/HIS4A and hisE/HIS4B as well as the two functional domains of hisD/HIS4C. The homologies between the bacterial and yeast sequences suggest a region of the hisD/HIS4C protein that may constitute one of the active centres. A large fragment at the amino terminal region of the yeast protein is missing from the bacterial hisIE gene product and is probably not needed for catalytic activity. Another region of non-homology in the yeast protein is probably a peptide bridge connecting the HIS4AB domain to HIS4C. Although the overall homology at the level of amino acid sequence is modest (about 38%) there is a striking similarity when the hydropathic patterns and predicted secondary structural configurations of these proteins are compared. 相似文献
9.
Domenico Osella Silvio Aime Danilo Boccardo Mario Castiglioni Luciano Milone 《Inorganica chimica acta》1985,100(1):97-105
The [Co2(CO)6(RC2R′)] complexes (R, R′ = H, Me, Et, Prn) react with molecular hydrogen under mild conditions of temperature and pressure, at low but appreciable rates. The effect of the steric hindrance of the substituents and the strength of the metalcarbon bonds are discussed. The kinetic data measured for [Co2(CO)6(HC2H)], suggest that both H2-coordination and CO-dissociation are involved in the rate-determining step of the overall hydrogenation process.The catalytic activity of [Co2(CO)6(HC2H)] in the homogeneous hydrogenation of acetylene is described. At low substrate/catalyst ratio the initial hydrogenation rate is equal, within experimental error, to that found for the stoichiometric reaction; on increasing the acetylene concentration, cyclotrimerization to benzene becomes the dominant process. Interestingly C4 hydrocarbons (mainly butadiene and 1-butene) are produced in measurable yield (?8%). The formation of these products is interpreted as the result of the hydrogenation of the elusive [Co2(CO)5(HC2H)2] complex, an unstable intermediate in the cyclotrimerization chain. 相似文献
10.