共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
In three cases of encephalitis in humans that occurred in the area where the newly described California virus was isolated from mosquitoes, serological evidence seemed to indict the California virus as the etiological agent. In the case of an infant with very severe disease, the serological evidence was convincing; the evidence was almost as strong in the case of a seven-year-old boy; the results in an adult were equivocal. Inapparent infection in man is quite common as indicated by neutralization tests on the sera of nearly 600 residents of California, but encephalitic manifestations of infection are extremely rare. In Kern County, California, where the virus was discovered, approximately 11 per cent of the population has been infected. Infection rates are higher in adults than in very young children. Absence of neutralizing antibodies from 64 specimens of blood from persons in Japan, Washington, and other states supports the specificity of the neutralization test in man and suggests that this virus is absent or is not being similarly transmitted in some areas. Serological evidence from serial bleedings of two sick horses suggested, but did not definitely establish, that this virus leads to a naturally acquired encephalomyelitis in horses. Serological tests with the viruses of western equine and St. Louis encephalitis did not lead to any other etiological diagnosis in the sick animals studied. Results of neutralization tests on the sera of eight horses and three cows in Kern County suggested extremely high infection rates, and an immunity rate of 18 per cent was noted in rabbits and ground squirrels. In the natural biological cycle rabbits and ground squirrels are suspected as the possible counterpart of birds in the St. Louis and western equine virus cycles. There is no evidence from field or laboratory to indicate that birds become infected with the California virus. Sera from 33 mammals other than man were collected from Northern California and Washington. All were free from neutralizing antibodies, again supporting the specificity of positive findings from Kern County. 相似文献
3.
Chakraborty D Ramakrishnan U Panor J Mishra C Sinha A 《Molecular phylogenetics and evolution》2007,44(2):838-849
A new species of primate, the Arunachal macaque Macaca munzala, belonging to the sinica species-group of the genus, was described from northeastern India in 2005, and, based on its appearance and distribution, hypothesised to be closely related to M. assamensis and M. thibetana. We subsequently obtained an entire adult male specimen and tissue remains from two other M. munzala individuals. Molecular analyses establish the distinct identity of the species and indicate a time of origin of c. 0.48 mya for it. The species also shows close phylogenetic affinities with the allopatric M. radiata and with the geographically closer M. assamensis and M. thibetana, possibly mediated by male introgression from an ancestral M. assamensis-M. thibetana stock into an ancestral M. munzala stock. Morphometric analyses, on the other hand, reiterate its close similarity only with M. assamensis and M. thibetana, presumably resulting from convergent evolution under similar ecological conditions and along a latitudinal gradient, as predicted by Bergmann's and Allen's rules. 相似文献
4.
5.
Isolates representing newly described Neosartorya species, and isolates with abnormal morphologies from Aspergillus section Fumigati were examined by phylogenetic analysis of sequences of part of their -tubulin gene. Phylogenetic analyses supported the earlier suggestions that heterothallism is a derived character, and that sexuality was lost several times during the evolution of Aspergillus section Fumigati. The heterothallic N. fennelliae and N. udagawae strains were found to be closely related to the homothallic Neosartorya sp. NRRL 4179 and N. aureola, respectively. Aspergillus sp. FRR 1266, which was earlier described as a variant of A. fumigatus, was found to be closely related to A. viridinutans. Another abnormal asexual isolate was found to be closely related to A. fumigatus and N. fischeri. Phylogenetic relationships among newly described Neosartorya species and other taxa were successfully established based on phylogenetic analysis of -tubulin sequences. 相似文献
6.
A Stolz T Yamada Y Sugiyama W Belknap N Kaplowitz 《Biochimica et biophysica acta》1984,800(2):171-177
As part of a study on the influence of dietary lipids on vitamin transport and metabolism in lactating cows, we have examined the beta-carotene content and other properties of fractions of the high-density lipoprotein (HDL, density 1.05-1.16 g/ml) of bovine blood. Our purpose was primarily to explain previous results indicating that feeding cows polyunsaturated lipids alters the properties of the HDL and increases the concentration of beta-carotene in the blood but not in the milk. Fractions of HDL of different particle size were prepared by gel-filtration chromatography and the particle diameters measured by electron microscopy. We found that large HDL particles contain more beta-carotene per unit weight than small particles. Furthermore the HDL from cows fed lipid-rich diets with a high proportion of linoleic-acid residues, which had been protected against microbial degradation in the rumen, had a high percentage of HDL particles with large diameters. The blood from these cows had a higher concentration of beta-carotene than before feeding polyunsaturated lipids, but their milk had a lower concentration. We suggest that HDL is the main store of beta-carotene in bovine blood. Moreover the concentration of beta-carotene in blood is increased by feeding polyunsaturated lipids largely because of the increase in the percentage of large HDL particles, which contain more beta-carotene. The effect on the concentration of beta-carotene in milk implies that the transfer mechanism is less efficient as a result of feeding polyunsaturated lipids. This lower efficiency may be due in part to the higher percentage of large HDL particles. 相似文献
7.
During a socioecological field study of Colombian spider monkeys, data were collected on spatial associations and social and ecological interactions among free-ranging Ateles belzebuth, Alouatta seniculus, Cebus apella, and Saimiri sciureus. The most frequently observed associations occurred between groups of squirrel and capuchin monkeys. Saimiri-Cebus associations were seen at all times of day and year, but no intertaxa play, passive body contact, or grooming interactions were observed. The Saimiri-Cebus association was paralleled by one between Saimiri and the small hawk, Harpagus bidentatus, and sometimes other insectivorous birds. These associations may be based in part on a complex balance of both mutual and one-sided foraging advantages. Less frequent associations between Ateles and Alouatta were based on mutual attraction to specific fruiting trees or contacts occurring on travel routes. Unlike the more frequently observed associations between Saimiri and Cebus, those between Ateles and Alouatta included both positive and negative interactions; for example, mutual play, grooming, and olfactory investigation as well as threats, chases, and supplantations. 相似文献
8.
The insertion sequence IS666 was isolated from Mycobacterium avium strain 101. IS666 is a 1474 bp insertion sequence belonging to the IS256 family, that includes IS6120 from Mycobacterium smegmatis, IS1166 and IS1295 from Rhodococcus sp. IGTS8, IST2 from Thiobacillus ferrooxidans, IS256 from Staphylococcus aureus, and ISRm3 from Rhizobium meliloti. IS666 has 24 bp imperfect inverted repeats that fit the consensus described for the family, and generates 9 bp duplications upon insertion into the host DNA with no apparent specificity in the target sequence. In contrast with its two closest homologues, IS1166 and IS6120, IS666 contains a single ORF that would codify a transposase of 434 aa. IS666 is restricted to M. avium, where it is present in 21% of the isolates in a number ranging between 1 to 7 copies. 相似文献
9.
A previously undescribed sub-group 2 rhabdovirus was isolated in Queensland from Datura stramonium with symptoms of vein yellowing, leaf distortion and reduced leaf size. Particles accumulated in the perinuclear space of infected cells of D. stramonium and measured 77 × 166 nm in preparations from sap. The virus was named datura yellow vein virus (DYVV) and was graft-transmitted to several hosts in the Solanaceae including Lycopersicon esculentum, Nicotiana tabacum and Solanum melongena, but not to Capsicum annuum or Solanum tuberosum. DYVV was not transmitted by mechanical inoculation and no insect vector was found. Purified particles of DYVV contained four structural proteins with molecular weights of about 78, 47, 41 and 36 kd. The 78 kd protein bound the lectin concanavalin A, thus identifying it as the viral glycoprotein. DYVV was serologically distinct from 11 other rhabdoviruses belonging to both subgroups, including potato chlorotic stunt, potato yellow dwarf (2 isolates) and tomato vein yellowing viruses. The glycoprotein only of DYVV cross-reacted with a polyclonal antiserum to sonchus yellow net virus. 相似文献
10.
《Harmful algae》2016
Blooms caused by some species belonging to the dinoflagellate genus Alexandrium are known to cause large-scale mortality of fish. Thus, the dynamics of these species is important and of concern to scientists, officials, and people in the aquaculture industry. To understand the dynamics of such species, their growth and mortality due to predation need to be assessed. The newly described dinoflagellate Alexandrium pohangense is known to grow slowly, with a maximum autotrophic growth rate of 0.1 d−1. Thus, it may not form bloom patches if its mortality due to predation is high. Therefore, to explore the mortality of A. pohangense due to predation, feeding on this species by the common heterotrophic dinoflagellates Gyrodinium dominans, Gyrodinium moestrupii, Luciella masanensis, Noctiluca scintillans, Oxyrrhis marina, Oblea rotunda, Polykrikos kofoidii, and Pfiesteria piscicida, as well as by the ciliate Tiarina fusus, was examined. None of these potential predators was able to feed on A. pohangense. In contrast, these potential predators were killed and their bodies were dissolved when incubated with A. pohangense cells or cell-free culture filtrates. The survival of G. moestrupii, O. marina, P. kofoidii, and T. fusus on incubation with 10 cells ml−1 of A. pohangense was 20–60%, while that at the equivalent culture filtrates was 20–70%. With increasing A. pohangense cell-concentration (up to 1000 cells ml−1 or equivalent culture filtrates), the survival rate of G. moestrupii, O. marina, P. kofoidii, and T. fusus rapidly decreased. The lethal concentration (LC50) for G. moestrupii, O. marina, P. kofoidii, and T. fusus at the elapsed time of 24 h with A. pohangense cells (cultures of 11.4, 13.3, 1.6, and 3.3 cells ml−1, respectively) was lower than that with A. pohangense filtrates (culture filtrates of 35.5, 30.6, 5.5, and 5.0 cells ml−1, respectively). Furthermore, most of the ciliates and heterotrophic dinoflagellates in the water collected from the coast of Tongyoung, Korea, were killed when incubated with cultures of 1000 A. pohangense cells ml−1 and equivalent culture filtrates. The relatively slow growing A. pohangense may form blooms by reducing mortality due to predation through killing potential protist predators. 相似文献
11.
We explored the feeding ecology of the newly described, nematocyst-bearing heterotrophic dinoflagellate Gyrodiniellum shiwhaense (GenBank accession number=FR720082). Using several different types of microscopes and high-resolution video-microscopy, we investigated feeding behavior and types of prey species that G. shiwhaense feeds upon. Additionally, we measured its growth and ingestion rates on its optimal algal prey, the cryptophyte Teleaulax sp. and the dinoflagellate Amphidinium carterae, as a function of prey concentration. These rates were measured for other edible prey at single prey concentrations at which the growth and ingestion rates of G. shiwhaense were saturated. After anchoring the prey with a tow filament, G. shiwhaense fed using a peduncle, ingesting small algal species with equivalent spherical diameters (ESDs) of <13 μm. However, it did not feed on larger algal species that had ESDs≥13 μm or the small diatom Skeletonema costatum. The specific growth rates for G. shiwhaense feeding upon Teleaulax sp. and A. carterae increased rapidly with increasing mean prey concentration before saturating at concentrations of ca. 180-430 ng C/ml. The maximum specific growth rate of G. shiwhaense on Teleaulax sp. and A. carterae were 1.05 and 0.82/d, respectively. However, Heterosigma akashiwo did not support positive growth of G. shiwhaense. The maximum ingestion rates of G. shiwhaense on Teleaulax sp. and A. carterae were 0.35 and 0.54 ng C/grazer/d, respectively. The calculated grazing coefficients attributable to G. shiwhaense on co-occurring cryptophytes and Amphidinium spp. were 0.01-1.87/d and 0.08-2.60/d, respectively. Our results suggest that G. shiwhaense can have a considerable grazing impact on algal populations. 相似文献
12.
Matrix metalloproteinases (MMPs) comprise a large group of endoproteinases that degrade all protein components of the extracellular matrix. Functionally, MMPs contribute to several different physiological as well as pathological conditions. The number of newly described MMPs has increased in recent years, although current knowledge about their expression pattern in various tissues remains incomplete. Here we analyzed the relative mRNA expression of the most recently described MMPs--MT5-MMP (MMP-24), MT6-MMP (MMP-25), MMP-27 and epilysin (MMP-28)--in a broad selection of rat tissues using real time-PCR. MMP-24 mRNA was found to be widely expressed with predominance in the central nervous system. MMP-25 mRNA, in contrast, exhibited peak expression levels in testis, kidney and skeletal muscle, differing from previously described distribution patterns in humans. mRNAs for MMP-27 and MMP-28 were generally expressed at a lower level. All four MMPs studied were detected at higher mRNA levels in bone and kidney, suggesting a possible role of these MMPs in physiological processes within these two organs. The present study highlights the differential distribution pattern of newly described MMPs among different tissues and underlines differences in the mRNA expression between different species. 相似文献
13.
14.
Wolbachia pipientis is an intracellular endosymbiont producing reproductive alterations in its hosts. This bacterium have been reported in many arthropods and nematodes. By PCR amplification and sequencing of the 16S rDNA and ftsZ genes we have identified a Wolbachia strain in the newly described sand-flea, Tunga trimamillata. Prevalence of this endosymbiont in the 26 individuals screened is equal to 35%. Sympatric and allopatric specimens of the related species Tunga penetrans were also analysed, but in contrast to literature data, Wolbachia appears absent in the presently analysed 24 specimens. Field studies evidence a female-biased sex-ratio in T. trimamillata, suggesting that Wolbachia may cause sex-ratio distortion in this species. By means of BLAST search and phylogenetic analysis we found that the Wolbachia strain from T. trimamillata pertains to the arthropod-infecting Wolbachia; this strain is highly differentiated from the Wolbachia strain of T. penetrans described in literature. 相似文献
15.
Asystasia mottle virus (AsMV) was detected serologically in samples of Asystasia gangetica with mottle symptoms, from several areas of tropical West Africa. It infected 12 species systemically and induced local lesions in a further four. The virus lost infectivity after dilution to 10-4, after 10 min at 75 °C and after 3 days at 27°C. Purified virus had an A260/A280 ratio of c. 1·2 and a protein subunit mol. wt of c. 33 000. Particles were c. 750 nm long and cytoplasmic inclusions typical of potyviruses were seen in ultrathin sections of infected leaves. The antiserum prepared had a titre of 1/1024 in microprecipitin tests but purified virus failed to react with 31 antisera to known potyviruses. The virus was transmitted in the non-persistent manner by Aphis spiraecola but only very infrequently. On the basis of these properties, AsMV is considered to be a new member of the potyvirus group. 相似文献
16.
Frölich K Jung S Ludwig A Lieckfeldt D Gibert P Gauthier D Hars J 《Journal of wildlife diseases》2005,41(3):606-610
A pestivirus was detected and characterized in chamois (Rupicapra pyrenaica pyrenaica) originating from the French part of the Pyrenees. Phylogenetic analysis of the pestivirus was done on the basis of a fragment from the 5' noncoding region including 22 published nucleotide sequences of different pestivirus strains. Our strain was grouped within the clade of border disease viruses (BDV). However, it had an intermediate position between clade BDV and classical swine fever viruses representing a basal position to BDV strains of domestic sheep. Our strain was grouped as a sister unit to a novel pestivirus (Chamois-1) recently described from chamois in Spain. Therefore, we postulate that this virus occurs in the entire population of Pyrenean chamois. On the basis of the phylogenetic grouping of this isolate, a postulated cross-species transmission of pestivirus from domestic sheep to chamois via shared pastures seems to be unlikely. 相似文献
17.
Martínez-Jiménez D Graham D Couper D Benkö M Schöniger S Gurnell J Sainsbury AW 《Journal of wildlife diseases》2011,47(2):442-454
An infectious disease caused by Squirrelpox virus has contributed to the decline of red squirrels, Sciurus vulgaris, in the British Isles. Because of the heightened disease surveillance activity in red squirrels, adenovirus infection with associated mortality has been detected. Adenoviral disease is described in other rodent species usually associated with stressors. Here we 1) describe the pathologic findings in red squirrels found dead with adenoviral infection and gastrointestinal disease, and 2) investigate the epizootiology of the disease through pathologic investigation, scanning surveillance, and virologic studies. Ten red squirrels involved in conservation studies were diagnosed with adenoviral infection by electron microscopy or PCR. All squirrels exhibited diarrhea and small intestinal inflammation or hemorrhage was evident in seven cases. Lesions indicative of splenic lymphocytolysis were observed in one squirrel and leukocytic hepatitis in another. No adenovirus was detected in grey squirrels, Sciurus carolinensis, inhabiting the same forest area, but previous serologic studies showed that grey squirrels cannot be discounted as a reservoir of the virus. Scanning surveillance showed that 12% of 493 red squirrels had diarrheal disease and two of 13 free-living red squirrels with diarrheal disease had adenovirus infection. Adenoviral disease in declining free-living wild red squirrel populations in the British Isles occurs at a detectable frequency and its impact on the conservation of this species deserves further attention. 相似文献
18.
19.
J. Michael Poston 《Archives of microbiology》1993,160(2):114-120
An organism from a goldfish aquarium, isolated on barbital medium, was found to be a Grampositive coccus which divided in alternating planes, often appearing as a doublet or as a tetrad with adjacent sides flattened. It grew well, although slowly, on rich solid medium (LB agar) and in liquid brain-heart infusion at room temperature (ca. 22°C); growth was slower and less extensive at 30°C or 37°C. No growth was seen at 4–5°C or at 42°C. It withstands brief exposure to ultraviolet radiation. Its growth was inhibited by low levels (0.1 unit/ml) of penicillin but was unaffected by levels of acetazolamide in excess of 1 mg/ml, indicating that it lacks carbonic anhydrase. Acid was not produced from glucose, maltose, mannose, lactose, or sucrose and only weakly, if at all, from fructose. Its DNA has a G+C mol percent of 59 measured chromatographically and neither the DNA nor rRNA from the organism hybridized with DNA from any organism that seemed related on morphological or other bases. Thin-layer chromatography of chloroform: methanol extracts of the organism show that it contains phosphatidyl choline, phosphatidyl ethanolamine, and phosphatidyl glycerol. Cell-wall preparations contain glutamic acid, serine, histidine, lysine, and alanine in the ratio of 1:1:1:1:8. Colonies were red-orange in color due, in larger measure, to a carotenoid tentatively identified as rhodopin. The organism was named Pelczaria aurantia.This paper is submitted in honor of Miss Dorothy Schoknecht of Kalispell, Montana, teacher prima inter pares 相似文献
20.
Cheng L MacLennan GT Abdul-Karim FW Lopez-Beltran A Montironi R 《Analytical and quantitative cytology and histology / the International Academy of Cytology [and] American Society of Cytology》2008,30(4):226-230
OBJECTIVE: To describe the morphologic, immunohistochemical and ultrastructural features of large, intensely eosinophilic cytoplasmic granules in prostatic epithelial cells in the benign prostate, as well as the prevalence of this condition. STUDY DESIGN: Two hundred twenty prostate needle biopsies and 104 radical prostatectomy specimens were examined for the presence of eosinophilic granules in benign prostatic epithelium. RESULTS: We found benign prostatic cells with bright eosinophilic granules in 13 of 84 (16%) negative prostate needle biopsies, 3 of 13 (23%) needle biopsies with high-grade prostatic intraepithelial neoplasia, 15 of 123 (12%) needle biopsies with adenocarcinoma and 21 of 104 (20%) radical prostatectomy specimens. Benign prostatic cells with eosinophilic granules were more commonly seen in prostatic ductal epithelium than acinar epithelium. They were usually focal and associated with variable degrees of chronic inflammation and atrophy. They differed from neuroendocrine cells with large eosinophilic granules by supranuclear location of granules, negative immunostaining for some neuroendocrine markers and presence of large exocrine-type electron-dense granules. CONCLUSION: Eosinophilic metaplasia of the prostate appears to represent a form of nonspecific histologic change in response to altered cellular milieu in the prostate. 相似文献