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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.
3.
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
4.
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
5.
A preliminary report on the use of transfer factor for treating stage D3 hormone-unresponsive metastatic prostate cancer 总被引:4,自引:0,他引:4
Dr. Giancarlo Pizza Caterina De Vinci Diego Cuzzocrea Domenico Menniti Ernesto Aiello Paolo Maver Giuseppe Corrado Piero Romagnoli Ennio Dragoni Giuseppe LoConte Umberto Riolo Aldopaolo Palareti Paolo Zucchelli Vittorio Fornarola Dimitri Viza 《Biotherapy》1996,9(1-3):123-132
As conventional treatments are unsuccessful, the survival rate of stage D3 prostate cancer patients is poor. Reports have
suggested the existence of humoral and cell-mediated immunity (CMI) against prostate cancer tumour-associated antigens (TAA).
These observations prompted us to treat stage D3 prostate cancer patients with an in vitro produced transfer factor (TF) able
to transfer, in vitro and in vivo, CMI against bladder and prostate TAA. Fifty patients entered this study and received one
intramuscular injection of 2–5 units of specific TF monthly. Follow-up, ranging from 1 to 9 years, showed that complete remission
was achieved in 2 patients, partial remission in 6, and no progression of metastatic disease in 14. The median survival was
126 weeks, higher than the survival rates reported in the literature for patients of the same stage. 相似文献
6.
Guido Barbujani Andrea Pilastro Silvia De Domenico Colin Renfrew 《American journal of physical anthropology》1994,95(2):137-154
The hypothesis that both genetic and linguistic similarities among Eurasian and North African populations are due to demic diffusion of neolithic farmers is tested against a wide database of allele frequencies. Demic diffusion of farming and languages from the Near East should have determined clines in areas defined by linguistic criteria; the alternative hypothesis of cultural transmission does not predict clines. Spatial autocorrelation analysis shows significant gradients in three of the four linguistic families supposedly affected by neolithic demic diffusion; the Afroasiatic family is the exception. Many such gradients are not observed when populations are jointly analyzed, regardless of linguistic classification. This is incompatible with the hypothesis that major cultural transformations in Eurasia (diffusion of related languages and spread of agriculture) took place without major demographic changes. The model of demic diffusion seems therefore to provide a mechanism explaining coevolution of linguistic and biological traits in much of the Old World. Archaeological, linguistic, and genetic evidence agree in suggesting a multidirectional process of gene flow from the Near East in the neolithic. However, the possibility should be envisaged that some allele frequency patterns can predate the neolithic and depend on the initial spread of Homo sapiens sapiens from Africa into Eurasia. © 1994 Wiley-Liss, Inc. 相似文献
7.
Potassium and Taurine Release Are Highly Correlated with Regulatory Volume Decrease in Neonatal Primary Rat Astrocyte Cultures 总被引:2,自引:0,他引:2
Domenico Vitarella †Darryl J. DiRisio †Harold K. Kimelberg Michael Aschner 《Journal of neurochemistry》1994,63(3):1143-1149
Abstract: Neonatal rat primary astrocyte cultures were swollen by exposure to hypotonic buffer. Using an electrical impedance method for determination of cell volume coupled with on-line measurements of efflux of radioactive ions or amino acids, we have investigated the role of K+ (using 86 Rb), taurine, and d -aspartate (an analogue of glutamate) in regulatory volume decrease (RVD). Addition of 1 m M quinine, 10 µ M nimodipine, 100 µ M BAPTA-AM, 10 µ M trifluoperazine, or a calcium-free buffer significantly ( p < 0.0001) inhibited RVD. This was accompanied by inhibition of 86 Rb release but an increase in d -[3 H]-aspartate release, which was proportional to the degree to which RVD was inhibited. These results support a regulatory role for calcium in RVD and show that inhibition of calcium entry from the extracellular fluid, intracellular calcium sequestration, inhibition of calcium-activated K+ channels, and inhibition of calmodulin all inhibit RVD. Because d -[3 H]aspartate efflux profiles increase as RVD is inhibited, it is unlikely that d -aspartate release is a main determinant of RVD. In contrast, [3 H]taurine release was increased by 1 m M quinine and inhibited by 10 µ M trifluoperazine. The net release of K+ and taurine is highly correlated with the degree of RVD, implicating a regulatory role for both K+ and taurine release in RVD. 相似文献
8.
9.
The activity of some phytotoxic metabolites of Pseudomonas syringae pv. syringae Van Hall strains B359 and B301 on in vivo and in vitro systems of H+-transport across the plasma membrane of maize (Zea mays L., hybrid Paolo) was investigated. In particular syringomycin, the first lipodepsinonapeptide isolated from Pss and already studied in plants and yeasts for its effects on several physiological systems, was compared with the recently described lipodepsipeptides with 22 or 25 amino acid residues, so called syringopeptins. The in vivo activity of the phytotoxins was tested on fusicoccin-stimulated H?-extrusion from cuttings of maize roots, which was inhibited by both types of toxins, with syringomycin more efficient than the syringopeptins. In vitro the H+-ATPase activity of predominantly right-side-out plasma membrane vesicles purified by two-phase partitioning was stimulated by 10 μM syringomycin and inhibited by higher levels, in agreement with the results of others with preparations of dicotyledons. Also the inhibition of the phosphohydrolytic activity of inside-out vesicles of mung bean plasma membrane was confirmed for maize. In both types of vesicles the syringopeptirts were better inhibitors than syringomycin. The pH gradient formed on addition of ATP to predominantly (25% latency) inside-out vesicles was immediately and completely collapsed by syringomycin and syringopeptins; H+-pumping was prevented if the toxins were added before ATP. The inhibition was concentration dependent, but at very low concentrations the effect was inverted. The results of the present investigation, carried out with maize preparations, confirm and extend the evidence so far obtained with dicotyledons in favour of the plasma membrane as an important site of interaction of syringomycin with the plant cell. They also indicate that, except for some details, the effects of syringopeptins at the level of the plasma membrane are the same as those of syringomycin. 相似文献
10.
Luigina Cellini Nerino Allocati Domenico Angelucci Teresa Iezzi Emanuela Di Campli Leonardo Marzio Benedetto Dainelli 《Microbiology and immunology》1994,38(11):843-850
An experimental rodent model was used to demonstrate the viability of the coccoid form of Helicobacter pylori. Concentrated suspensions were prepared for the two different morphologies: at 2 days incubation for the bacillary forms and at 20 days incubation for the “dormant” forms. The strains used for incubation were two fresh isolates from humans with duodenal ulceration, and two collection strains. Five hundred microliters of culture (OD550 = 5 Mc Farland) of Helicobacter pylori with bacillary (2-5×109 CFU/ml) and coccoid (0 CFU/ml) morphology were inoculated intragastrically in BALB/c mice. The gastric mucosa of the mice was colonized by Helicobacter pylori with the administration of fresh bacillary and coccoid cultures and not with the established cultures. Helicobacter pylori was isolated at 1 week after inoculation with the administration of fresh bacillary cultures, while fresh coccoid Helicobacter pylori was recovered in mice stomachs after 2 weeks of inoculation. After colonization, histopathologic changes occurred after 1 month from inoculation; all colonized mice showed a systemic antibody response to Helicobacter pylori. These results support the thesis of the viability of coccoid Helicobacter pylori non-culturable in vitro and confirm that concentrated bacterial suspensions are able to colonize and to produce gastric alterations in this suitable animal model. 相似文献