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11.
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A neonate with aniridia was found to have a one band paracentric inversion of the short arm of chromosome 4. This was initially difficult to interpret on high resolution banding. The inversion was present in three generations of the family. 相似文献
13.
W B Watt 《The Journal of biological chemistry》1972,247(5):1445-1451
14.
In some animals sex is determined after conception by environmental factors (environmental sex determination. ESD). In the amphipod Gammarus duebeni sex is reportedly determined by photoperiod: there is a higher proportion of males in broods reared under long-day than under short-day photoperiods. It has been proposed that this is an adaptive response to seasonal population dynamics. A test of the hypothesis would be to demonstrate changes in the degree to which sex is determined by the environment in populations from different latitudes with different dynamics. This study reports such a test. Environmental response is significantly less strong in a southern population with a long breeding season than in a northern one in which breeding is seasonally restricted. Moreover, the threshold of the ESD cue for male or female determination is not defined when the breeding season is weakly seasonal. There is a broad correlation between latitude (and hence breeding seasonality) and the strength of ESD response across a series of population studies. Similarities between the Gammarus system of sex determination and that of the Atlantic silverside Menidia menidia, a fish with thermal ESD, are discussed. 相似文献
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16.
Stephen M. Techtmann Julian L. Fortney Kati A. Ayers Dominique C. Joyner Thomas D. Linley Susan M. Pfiffner Terry C. Hazen 《PloS one》2015,10(3)
The waters of the Eastern Mediterranean are characterized by unique physical and chemical properties within separate water masses occupying different depths. Distinct water masses are present throughout the oceans, which drive thermohaline circulation. These water masses may contain specific microbial assemblages. The goal of this study was to examine the effect of physical and geological phenomena on the microbial community of the Eastern Mediterranean water column. Chemical measurements were combined with phospholipid fatty acid (PLFA) analysis and high-throughput 16S rRNA sequencing to characterize the microbial community in the water column at five sites. We demonstrate that the chemistry and microbial community of the water column were stratified into three distinct water masses. The salinity and nutrient concentrations vary between these water masses. Nutrient concentrations increased with depth, and salinity was highest in the intermediate water mass. Our PLFA analysis indicated different lipid classes were abundant in each water mass, suggesting that distinct groups of microbes inhabit these water masses. 16S rRNA gene sequencing confirmed the presence of distinct microbial communities in each water mass. Taxa involved in autotrophic nitrogen cycling were enriched in the intermediate water mass suggesting that microbes in this water mass may be important to the nitrogen cycle of the Eastern Mediterranean. The Eastern Mediterranean also contains numerous active hydrocarbon seeps. We sampled above the North Alex Mud Volcano, in order to test the effect of these geological features on the microbial community in the adjacent water column. The community in the waters overlaying the mud volcano was distinct from other communities collected at similar depths and was enriched in known hydrocarbon degrading taxa. Our results demonstrate that physical phenomena such stratification as well as geological phenomena such as mud volcanoes strongly affect microbial community structure in the Eastern Mediterranean water column. 相似文献
17.
Nicholas Cianciotto Terry Serwold-Davis Neal Groman Giulio Ratti Rino Rappuoli 《FEMS microbiology letters》1990,66(1-3):299-301
Chromosomal restriction fragments of Corynebacterium ulcerans and C. diphtheriae, containing an integration site for corynephages of the beta family, show homology on Southern blots. Homologous DNA in also found in the soil isolate C. glutamicum, although this strain is not susceptible to beta-corynephages. Three of these DNA fragments, one for each bacterial strain, and a fragment of gamma-corynephage DNA previously shown to contain the phage integration site, were cloned and sequenced. Alignment of the 3 bacterial sequences shows a very high degree of homology in a stretch of ca 120 nucleotides, whereas the rest of the sequences is generally non-homologous. Within this common bacterial portion, a segment of ca. 96 nucleotides (core sequence) is also highly homologous to the phage sequence. The first half (ca. 50 bp) of the core sequence is identical in all aligned sequences whereas the second half, which is largely occupied by a stem-and-loop structure, contains point mutations peculiar to each clone. The described sequences are likely to be involved in phage integration/excision processes. 相似文献
18.
A phylogenetic analysis and revised classification of the Monocotylidae Taschenberg, 1879 (Monogenea) 总被引:1,自引:0,他引:1
The Monocotylidae Taschenberg, 1879 is revised based on a cladistic analysis of relationships between the constituent species and genera. The monophyly of the family is supported by three apomorphic character states: division of the haptor into one central and eight peripheral loculi; the ovary looping the right intestinal caecum; and tetrahedral eggs. The family is divided into six subfamilies: Calicotylinae Monticelli, 1903 (comprising Calicotyle Diesing, 1850, Dictyocotyle Nybelin, 1941); Dasybatotreminae Bychowsky, 1957 (comprising Anoplocotyloides Young, 1967, Dasybatotrema Price, 1938, Timofeevia n. g., Troglocephalus Young, 1967); Decacotylinae n. subfam. (comprising Decacotyle Young, 1967, Papillicotyle Young, 1967); Heterocotylinae n. subfam. (comprising Heterocotyle Scott, 1904, Neoheterocotyle Hargis, 1955, Nonacotyle Ogawa, 1991, Potamotrygonocotyle Mayes, Brooks & Thorson, 1981, Spinuris Doran, 1953); Merizocotylinae Johnston & Tiegs, 1922 (comprising Cathariotrema Johnston & Tiegs, 1922, Empruthotrema Johnston & Tiegs, 1922, Merizocotyle Cerfontaine, 1894, Squalotrema Kearn & Green, 1983, Triloculotrema Kearn, 1993); and Monocotylinae Taschenberg, 1879 (comprising Clemacotyle Young, 1967, Dendromonocotyle Hargis, 1955, Monocotyle Taschenberg, 1878). The Dendromonocotylinae Hargis, 1955 is removed from subfamilial status and the two genera previously assigned to the subfamily are reassigned to the Monocotylinae. Timofeevia is proposed for Timofeevia rajae (Timofeeva, 1983) n. comb. (formerly Dasybatotrema rajae). Mycteronastes Kearn & Beverley-Burton, 1990 and Thaumatocotyle Scott, 1904 are synonymised with Merizocotyle. Gymnocalicotyle Nybelin, 1941 is not considered a distinct taxon. Revised diagnoses and keys for subfamilies and genera of the Monocotylidae are provided. 相似文献
19.
R. Myles Riner Kathryn Maino Collins Garrett E. Foulke George V. Moorhead Phillip Terry 《The Western journal of medicine》1987,147(5):602-608
In a pilot project sponsored by the California State Emergency Medical Services Authority, validated, verifiable criteria were developed for the vertical categorization of hospital emergency services in 11 different groupings of medical and surgical emergencies. We describe the development of an assessment process and categorization criteria to identify the most appropriate receiving facility for interfacility transfer and, in selected instances, field triage of patients with different levels of severity of illness or injury. We propose that this facility assessment project be used in the critical care planning process for the eventual vertical categorization of hospital emergency services in California and as a template for similar projects in other states. 相似文献
20.
King Frederick D.; Cucci Terry L.; Townsend David W. 《Journal of plankton research》1987,9(2):277-289
Ammonium regeneration by micro- (35153 µm) andmacrozooplankton (> 153 µm) was determined in the Gulfof Maine by measuring the activity of the excretory enzyme glutamatedehydrogenase (GDH) in various size fractions. GDH maxima weregenerally observed to correspond to the depth of the chlorophyllmaximum as previously reported in the Gulf of Mexico and inthe vicinity of the Nantucket Shoals. GDH activity of the microzooplanktonwas considerably lower than the macrazooplankton, suggestingthe microzooplankton made only a minor contribution (111%) to the total ammonium regenerated. These results were confirmedby biomass estimates made from counts of individual species.Ammonium excretion by both zooplankton fractions was estimatedto supply 531 % of the nitrogen requirements for primaryproduction, with an estimated 5963% supplied by the verticaltransport of nitrate (new nitrogen) into the euphoric zone. 相似文献