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41.
Anne M. Lauwers Wolfgang Heinen Leon G. M. Gorris Chris van der Drift 《Applied microbiology and biotechnology》1990,33(3):352-358
Summary Biofilm development in methanogenic fluidized-bed reactors with sand as the carrier was studied on a laboratory scale. The microorganisms present in consecutive layers of the biofilm of mature sludge granules were preliminarily characterized on the basis of their morphology, element composition and adhesion capacity and were compared to bacteria which take part in the initial colonization of sand. The early phase of biofilm development was monitored with reactors receiving waste-waters containing different mixtures of volatile fatty acids and inoculated with fluidized-bed reactor effluent for different lengths of time. The results obtained indicate that facultative anaerobic bacteria abundantly present in the outermost biofilm layers of mature sludge granules are probably the main primary colonizers of the sand. Methanothrix spp. or other methanogens were rarely observed among the primary colonizers. The course of biofilm formation was comparable under the various start-up conditions employed including variations in waste-water composition, inoculation and anaerobicity. However, omission of waste-water and thus of substrate resulted in rapid wash-out of the attached biomass.
Offprint requests to: W. Heinen 相似文献
42.
Alexander C. Keyel Morgan E. Gorris Ilia Rochlin Johnny A. Uelmen Luis F. Chaves Gabriel L. Hamer Imelda K. Moise Marta Shocket A. Marm Kilpatrick Nicholas B. DeFelice Justin K. Davis Eliza Little Patrick Irwin Andrew J. Tyre Kelly Helm Smith Chris L. Fredregill Oliver Elison Timm Karen M. Holcomb Michael C. Wimberly Matthew J. Ward Christopher M. Barker Charlotte G. Rhodes Rebecca L. Smith 《PLoS neglected tropical diseases》2021,15(9)
West Nile virus (WNV) is a globally distributed mosquito-borne virus of great public health concern. The number of WNV human cases and mosquito infection patterns vary in space and time. Many statistical models have been developed to understand and predict WNV geographic and temporal dynamics. However, these modeling efforts have been disjointed with little model comparison and inconsistent validation. In this paper, we describe a framework to unify and standardize WNV modeling efforts nationwide. WNV risk, detection, or warning models for this review were solicited from active research groups working in different regions of the United States. A total of 13 models were selected and described. The spatial and temporal scales of each model were compared to guide the timing and the locations for mosquito and virus surveillance, to support mosquito vector control decisions, and to assist in conducting public health outreach campaigns at multiple scales of decision-making. Our overarching goal is to bridge the existing gap between model development, which is usually conducted as an academic exercise, and practical model applications, which occur at state, tribal, local, or territorial public health and mosquito control agency levels. The proposed model assessment and comparison framework helps clarify the value of individual models for decision-making and identifies the appropriate temporal and spatial scope of each model. This qualitative evaluation clearly identifies gaps in linking models to applied decisions and sets the stage for a quantitative comparison of models. Specifically, whereas many coarse-grained models (county resolution or greater) have been developed, the greatest need is for fine-grained, short-term planning models (m–km, days–weeks) that remain scarce. We further recommend quantifying the value of information for each decision to identify decisions that would benefit most from model input. 相似文献
43.
Caruso P Gorris MT Cambra M Palomo JL Collar J López MM 《Applied and environmental microbiology》2002,68(7):3634-3638
Sensitive and specific routine detection of Ralstonia solanacearum in symptomless potato tubers was achieved by efficient enrichment followed by a reliable double-antibody sandwich indirect enzyme-linked immunosorbent assay based on the specific monoclonal antibody 8B-IVIA. This monoclonal antibody reacted with 168 typical R. solanacearum strains and did not recognize 174 other pathogenic or unidentified bacteria isolated from potato. The optimized protocol included an initial enrichment step consisting of shaking the samples in modified Wilbrink broth for 72 h at 29 degrees C. This step enabled specific detection by the enzyme-linked immunosorbent assay of 1 to 10 CFU of R. solanacearum per ml of initial potato extract. Analysis of 233 commercial potato lots by this method provided results that coincided with the results of conventional methods. 相似文献
44.
Summary A quantitative assay for analogues of coenzyme F420 is presented. The assay combines separation of the coenzymes by binary reversed-phase high performance liquid chromatography with detection by fluorescence, yielding high specificity and sensitivity. Quantification is by calibration with a coenzyme F420 standard or by employing coenzyme F420 fragments as internal standards. 相似文献
45.
B. J. O. Efiuvwevwere L. G. M. Gorris E. J. Smid E. P. W. Kets 《Applied microbiology and biotechnology》1999,51(1):100-104
Survival of Lactococcus lactis subjected to different drying conditions was investigated. Mannitol most remarkably enhanced the survival of dried cells
to a level almost equalling that of viable cells [log10 (cfu ml−1) = 9.42] as was found prior to the drying process (log10 = 9.6). In the absence of mannitol, a survival was reduced by a factor of 104. Drying of cells at 20 °C led to higher survival rates than drying at 30 °C. Mannitol enhanced the survival rate at both
temperatures, and at both 20 °C and 30 °C the highest reduction in survival occurred when cells were dried at a water activity
of 0.76. In the presence of mannitol, differences in survival after drying at different water activities were less pronounced.
Rehydration of cells dried in the presence of mannitol resulted in an extended lag phase of 4 h compared to fresh cells. No
growth or acidification of the culture medium was observed for 12 h in the case of rehydrated cells dried in the absence of
mannitol. It was hypothesized that a radical scavenging activity of mannitol could partly explain these observations.
Received: 28 August 1998 / Accepted: 2 October 1998 相似文献
46.
Archaeoglobus fulgidus is an extremely thermophilic, sulphate reducing archaebacterium thought to represent a biochemical missing-link between sulphur-metabolizing bacteria and methanogenic bacteria. Whereas the phylogenetic position of A.fulgidus is closer to the sulphur-metabolizing bacteria, there is a partial overlap in the biochemical machinery of A.fulgidus with both groups of bacteria. In particular, the presence of a number of aberrant cofactors up to now thought to be involved exclusively in the process of methanogenesis in methanogenic archaebacteria, i.e. coenzyme F420, methanofuran and methanopterin, has been indicated by previous studies. Here we present evidence for the structural identity of the methanopterin cofactor of A.fulgidus with the methanopterin isolated from Methanobacterium thermoautotrophicum and show that this non-methanogenic bacterium contains two as yet unknown analogues of coenzyme F420. The levels of the various cofactors were determined in cultures grown either on formate or lactate as the carbon source and sulphate or thiosulphate as the sulphur source. 相似文献