This work describes the length-weight relationship (LWR) of ten fish species from the Contas River Basin, Bahia State, Brazil. Sampling was conducted quarterly between November 2012 and November 2013 in 18 wadeable streams (nine in the Diamantina Plateau, Caatinga biome, and nine in the Atlantic forest biome). The fishes were caught using electrofishing (800V DC) and hand nets (2.0 mm mesh size) in 50 meters stretch by the sample unit. Collected fishes were fixed in formalin and preserved in alcohol, and thus some shrinking probably occurred. The values of parameter b of the LWR (W = aLb) ranged between 2.763 and 3.267. It is the first record of LWR parameters for nine species, all endemic to Northeastern Mata Atlântica freshwater ecoregion (NMAF). Moreover, new maximum lengths are presented for five species. 相似文献
Migration has an important impact on the transmission of pathogens. Migratory birds disperse parasites through their routes and may consequently introduce them to new areas and hosts. Hence, haemosporidian parasites, which are among the most prevalent, diverse and important bird pathogens, are potentially dispersed when infecting migrant hosts. Further, migrant hosts could enhance local parasite prevalence and richness by transporting new parasite strains to new areas. Here, we hypothesize and aim to evaluate if 1) migratory birds spread parasite lineages along their routes, and 2) localities crossed by more migratory birds have greater prevalence and richness of haemosporidians. For the first hypothesis, we tested whether parasite lineages found 1) in both migrants and residents, and 2) only in residents, differ in their frequencies of occurrence among localities. For the second hypothesis, we tested for a relationship among localities between the overall local haemosporidian parasite richness and prevalence, and the proportion of migratory bird individuals present in a locality. We combined a dataset on 13 200 bird samples with additional data from the MalAvi database (total: ~2800 sequenced parasites comprising 675 distinct lineages, from 506 host species and 156 localities) from South America, and used Bayesian multi-level models to test our hypotheses. We demonstrate that parasites shared between resident and migratory species are the most spatially widespread, highlighting the potential of migrants to carry and transmit haemosporidians. Further, the presence of migrants in a locality was negatively related to local parasite richness, but not associated with local prevalence. Here, we confirm that migrants can contribute to parasite dispersal and visiting migrants are present in regions with lower Plasmodium prevalence. Also, we observed their presence might raise Haemoproteus community prevalence. Therefore, we demonstrate migrants enhance pathogens spread and their presence may influence parasite community transmission. 相似文献
This study evaluated such as exposure to ethinylestradiol during the prenatal (18th–22nd day) and pubertal (42nd–49th day) periods acts on the male ventral prostate and female prostate of 12-month old gerbils. We performed the analysis to serum hormone levels for estradiol and testosterone. The prostates were submitted to morphometric and immunohistochemical analyses. Exposure to ethinylestradiol during these developmental periods decreased the testosterone serum levels in males and increased the estradiol serum levels in females. Morphologically, prostate intraepithelial neoplasia and disorders in the arrangement of the fibrous components were observed in the prostate glands of both sexes of gerbil exposed to ethinylestradiol during development periods. In the male prostate, the ethinylestradiol promoted decreased in the frequency of positive epithelial cell for androgen receptor (AR) and increased the frequency of positive stromal cell for estrogen receptor α. However, in the female prostate, this synthetic estrogen caused AR upregulation and increased cell proliferation. This study shows that the exposure to ethinylestradiol during development phases alters the morphology and the hormonal signaling in the male and female prostates of old gerbils, confirming the action of ethinylestradiol as endocrine disruptor. 相似文献
Limnology - Allochthonous organic matter in low-order streams is, in general, mainly composed of senescent leaves. However, in tropical streams green leaves can represent an important source of... 相似文献
Agoutis, Dasyprocta spp., are medium-sized rodents distributed in Neotropical region. Their diet is usually described as granivorous/frugivorous, and agoutis are recognised as important seed dispersers. Here, we present two spatially and temporally independent records of egg predation by Azara’s agouti, Dasyprocta azarae, in fragments of Cerrado savanna forest. In both cases, the agoutis ingested quail eggs that had been placed in artificial nests at ground level, 100 m from the edge of the forest. As Dasyprocta is a herbivorous rodent, this predatory behaviour is unexpected and may represent an opportunistic foraging strategy. These observations provide important new insights into the feeding biology of agoutis and highlight the value of camera traps as a tool for the collection of data on the behavioural ecology and natural history of vertebrates in general. 相似文献
On a global scale, invasive grasses threaten biodiversity and ecosystem function. Nevertheless, the importation of forage grasses is a significant economic force driven by globalization. Pastureland and rangeland are of critical economic and ecological importance, but novel grass species may lead to invasion. Recognizing that economically important species can also be ecologically damaging creates a contentious debate for land managers, policymakers, and ecologists alike. Many Afrotropical perennial grass species have been intentionally introduced pantropically given their high forage production and resistance to stress. However, these traits may also confer competitive ability, increasing the possibility of unintended escape and invasion. Further, these traits have posed challenges for traditional control methods using chemicals, prescribed fire, and mowing. The use of classic biological control may alleviate the ecological impact in invaded areas. In this literature synthesis we examine Guinea grass (Megathyrsus maximus); whose economic value in many countries is undeniable, yet its impact on native ecosystems is a mounting concern. First, we introduce Guinea grass taxonomy, general biology and ecology, and the geographic and genetic origins. Second, we review the economic value and the ecological impacts. Third, we review the control of Guinea grass in undesired areas using chemical and mechanical means. Finally, we review current efforts to use biological control.
Probiotics and Antimicrobial Proteins - Skin wounds are an important clinical problem which affects millions of people worldwide. The search for new therapeutic approaches to improve wound healing... 相似文献
Probiotics and Antimicrobial Proteins - This study aimed to produce a probiotic-containing functional wheat beer (PWB) by an axenic culture system with potential probiotic Saccharomyces cerevisiae... 相似文献