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61.
Arathy D. S. Nair Chuanmin Cheng Chanran K. Ganta Michael W Sanderson Arthur R. Alleman Ulrike G. Munderloh Roman R. Ganta 《PloS one》2016,11(2)
Dogs acquire infections with the Anaplasmataceae family pathogens, E. canis, E. chaffeensis, E. ewingii, A. platys and A. phagocytophilum mostly during summer months when ticks are actively feeding on animals. These pathogens are also identified as causing diseases in people. Despite the long history of tick-borne diseases in dogs, much remains to be defined pertaining to the clinical and pathological outcomes of infections with these pathogens. In the current study, we performed experimental infections in dogs with E. canis, E. chaffeensis, A. platys and A. phagocytophilum. Animals were monitored for 42 days to evaluate infection-specific clinical, hematological and pathological differences. All four pathogens caused systemic persistent infections detectible throughout the 6 weeks of infection assessment. Fever was frequently detected in animals infected with E. canis, E. chaffeensis, and A. platys, but not in dogs infected with A. phagocytophilum. Hematological differences were evident in all four infected groups, although significant overlap existed between the groups. A marked reduction in packed cell volume that correlated with reduced erythrocytes and hemoglobin was observed only in E. canis infected animals. A decline in platelet numbers was common with E. canis, A. platys and A. phagocytophilum infections. Histopathological lesions in lung, liver and spleen were observed in all four groups of infected dogs; infection with E. canis had the highest pathological scores, followed by E. chaffeensis, then A. platys and A. phagocytophilum. All four pathogens induced IgG responses starting on day 7 post infection, which was predominantly comprised of IgG2 subclass antibodies. This is the first detailed investigation comparing the infection progression and host responses in dogs after inoculation with four pathogens belonging to the Anaplasmataceae family. The study revealed a significant overlap in clinical, hematological and pathological changes resulting from the infections. 相似文献
62.
Horizontal transmission, vertical inactivation, and stochastic loss of mariner-like transposable elements 总被引:8,自引:5,他引:8
Horizontal transmission has been well documented as a major mechanism for
the dissemination of mariner-like elements (MLEs) among species. Less well
understood are mechanisms that limit vertical transmission of MLEs
resulting in the "spotty" or discontinuous distribution observed in closely
related species. In this article we present evidence that the genome of the
common ancestor of the melanogaster species subgroup of Drosophila
contained an MLE related to the mellifera (honey bee) subfamily. Horizontal
transmission, approximately 3-10 MYA, is strongly suggested by the
observation that the sequence of the MLE in Drosophila erecta is 97%
identical in nucleotide sequence with that of an MLE in the cat flea,
Ctenocephalides felis. The D. erecta MLE has a spotty distribution among
species in the melanogaster subgroup. The element has a high copy number in
D. erecta and D. orena, a moderate copy number in D. teissieri and D.
yakuba, and was apparently lost ("stochastic loss") in the lineage leading
to D. melanogaster, D. simulans, D. mauritiana, and D. sechellia. In D.
erecta, most copies are concentrated in the heterochromatin. Two copies
from D. erecta, denoted De12 and De19, were cloned and sequenced, and they
appear to be nonfunctional ("vertical inactivation"). It therefore appears
that the predominant mode of MLE evolution is vertical inactivation and
stochastic loss balanced against occasional reinvasion of lineages by
horizontal transmission.
相似文献
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64.
The spotted seed allele R-stippled (R-st) is comprised of the following genetic components: strong seed color (Sc), inhibitor-of-R (I-R) and near-colorless seed (Nc). I-R is a mobile element that represses (Sc) expression irregularly. Germinal I-R losses produce progeny with fully colored seed. Southern blot analysis revealed four r-hybridizing segments in R-st and three, two or one in two sets of unequal crossover deletion products. By comparison to published reports of r gene structure, we maintain that each segment contains at least one r gene. The proximal r gene, Sc, confers strong seed color; the three distal r genes together produce near-colorless seed. R-st's seed spotting phenotype is correlated with the presence of a 3.3-kb insert in Sc identified as I-R. The level of the near-colorless phenotype is inversely correlated with the number of r genes present, suggesting involvement of a multiple copy silencing mechanism in their regulation. Phenotypic changes in R-st occurred primarily by unequal exchange between r genes. The locations of exchange positions showed a strong polarity, nearly all occurring in the 3' portions of the identified r genes. 相似文献
65.
Katherine A. Sayler Anthony F. Barbet Casey Chamberlain William L. Clapp Rick Alleman Julia C. Loeb John A. Lednicky 《PloS one》2014,9(12)
Arenaviridae are a family of single stranded RNA viruses of mammals and boid snakes. Twenty-nine distinct mammalian arenaviruses have been identified, many of which cause severe hemorrhagic disease in humans, particularly in parts of sub-Saharan Africa, and in Central and South America. Humans typically become infected with an arenavirus through contact with excreta from infected rodents. Tacaribe virus (TCRV) is an arenavirus that was first isolated from bats and mosquitoes during a rabies surveillance survey conducted in Trinidad from 1956 to 1958. Tacaribe virus is unusual because it has never been associated with a rodent host and since that one time isolation, the virus has not been isolated from any vertebrate or invertebrate hosts. We report the re-isolation of the virus from a pool of 100 host-seeking Amblyomma americanum (lone star ticks) collected in a Florida state park in 2012. TCRV was isolated in two cell lines and its complete genome was sequenced. The tick-derived isolate is nearly identical to the only remaining isolate from Trinidad (TRVL-11573), with 99.6% nucleotide identity across the genome. A quantitative RT-PCR assay was developed to test for viral RNA in host-seeking ticks collected from 3 Florida state parks. Virus RNA was detected in 56/500 (11.2%) of surveyed ticks. As this virus was isolated from ticks that parasitize humans, the ability of the tick to transmit the virus to people should be evaluated. Furthermore, reservoir hosts for the virus need to be identified in order to develop risk assessment models of human infection. 相似文献
66.
67.
68.
Christine Grieshop Elizabeth Flickinger Kari Bruce AR Patil GL Czarnecki-Maulden GC Fahey Jr 《Archives of animal nutrition》2013,67(6):483-494
Thirty-four senior dogs (pointers 8 - 11 years, beagles 9 - 11 years) were used to evaluate the effects of oligosaccharides on nutritional and immunological characteristics. Dogs were randomly allotted to treatments [1% chicory (CH), 1% mannan-oligosaccharide (MOS), 1% chicory + 1% MOS (CM), or no supplementation (control, CON)] in a parallel design with a 4 week baseline period followed by a 4 week treatment period. Dietary supplementation with MOS or CM tended (P = 0.07) to increase food intake due, in part, to an increase in fermentable fibre and a decrease in energy content of the diet. Although wet faecal output increased (P < 0.05) for dogs supplemented with MOS or CM, when corrected for food intake, no differences were noted. The CM treatment increased (P < 0.05) faecal score (1 = hard and dry, 5 = watery liquid), although these scores remained in a desirable range (3 to 3.5). Chicory supplementation increased (P = 0.07) fat digestibility. Chicory or MOS increased (P 0.05) faecal bifidobacteria concentrations 0.4 and 0.5 log10 cfu/g DM, respectively, compared to the CON, while MOS decreased (P < 0.05) faecal E. coli concentrations. Oligosaccharides did not affect white blood cell (WBC) concentrations, but CH and CM tended to increase (P = 0.10) neutrophil concentrations compared to control dogs. Peripheral lymphocyte concentrations were decreased in dogs supplemented with MOS (P = 0.06) and CM (P < 0.05). Chicory and MOS alter faecal microbial populations and certain indices of the immune system of senior dogs. 相似文献
69.
70.
Amino acid sequence versus morphological data and the interordinal relationships of mammals 总被引:2,自引:0,他引:2
To a large extent, the mutual affinities of the mammalian orders continue
to puzzle systematists, even though comparative anatomy and amino acid
sequencing offer a massive data base from which these relationships could
potentially be adduced. In the present paper the consistency index--the
number of character states less the number of characters in a data set,
divided by the total number of changes in the character states on a
cladogram--was used to examine the relative resolving powers of recently
published morphological and molecular- sequence data. Consistency indices
were calculated for previously published alpha crystallin A chain and
myoglobin amino acid-sequence cladograms and for four original amino
acid-sequence cladograms (alpha crystallin A, myoglobin, and alpha and beta
hemoglobin); these were found to be comparable to the consistency indices
of morphologically based cladograms. Qualitative comparisons between the
morphologically based and molecularly based trees were also made; only
moderate congruence between the two was observed. Moreover, there was a
general lack of congruence between the cladograms specified by each of the
four proteins. Amino acid-sequence and morphological data agreed on the
placement of edentates as an early eutherian offshoot and on the grouping
of hyracoids, proboscideans, and sirenians. Otherwise there was only
limited congruence: morphology strongly supported the grouping of
lagomorphs and rodents and the alliance of pholidotes and edentates, but
sequence analyses did not. The placement of tubulidentates differed widely
among proteins. Morphology indicated the close association of sirenians
with proboscideans; proteins suggested a pairing of sirenians with
hyracoids. Sequence data did not identify many (morphologically
well-diagnosed) orders as monophyletic (e.g., Lagomorpha).(ABSTRACT
TRUNCATED AT 250 WORDS)
相似文献