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81.
Raquel Soares Maia Godoy Luiza dos Santos Felix Alessandra da Silva Orfan Brbara Aparecida Chaves Paula Monalisa Nogueira Breno dos Anjos Costa Aline Silva Soares Cinthia Catharina Azevedo Oliveira Rafael Nacif-Pimenta Breno Mello Silva Ana Paula Duarte Marcus Vinicius Guimares de Lacerda Wuelton Marcelo Monteiro Ngila Francinete Costa Secundino Paulo Filemon Paolucci Pimenta 《PLoS neglected tropical diseases》2021,15(11)
Dengue virus (DENV) and Zika virus (ZIKV) belong to the same viral family, the Flaviviridae. They cause recurring threats to the public health systems of tropical countries such as Brazil. The primary Brazilian vector of both viruses is the mosquito Aedes aegypti. After the mosquito ingests a blood meal from an infected person, the viruses infect and replicate in the midgut, disseminate to secondary tissues and reach the salivary gland (SG), where they are ready to be transmitted to a vertebrate host. It is thought that the intrinsic discrepancies among mosquitoes could affect their ability to deal with viral infections. This study confirms that the DENV and ZIKV infection patterns of nine Ae. aegypti field populations found in geographically separate health districts of an endemic Brazilian city vary. We analyzed the infection rate, disseminated infection, vector competence, and viral load through quantitative PCR. Mosquitoes were challenged using the membrane-feeding assay technique and were tested seven and fourteen days post-infection (early and late infection phases, respectively). The infection responses varied among the Ae. aegypti populations for both flaviviruses in the two infection phases. There was no similarity between DENV and ZIKV vector competencies or viral loads. According to the results of our study, the risk of viral transmission overtime after infection either increases or remains unaltered in ZIKV infected vectors. However, the risk may increase, decrease, or remain unaltered in DENV-infected vectors depending on the mosquito population. For both flaviviruses, the viral load persisted in the body even until the late infection phase. In contrast to DENV, the ZIKV accumulated in the SG over time in all the mosquito populations. These findings are novel and may help direct the development of control strategies to fight dengue and Zika outbreaks in endemic regions, and provide a warning about the importance of understanding mosquito responses to arboviral infections. 相似文献
82.
Hospital-acquired methicillin-resistant Staphylococcus aureus (MRSA) has been an increasing problem worldwide since the initial reports over 40 years ago. To examine new drug leads with potential antibacterial activities, 14 p-substituted benzoic acid [(5-nitro-thiophen-2-yl)-methylene]-hydrazides were designed, synthesized, and tested against standard and multidrug-resistant S. aureus strains by serial dilution tests. All compounds exhibited significant bacteriostatic activity and some of them also showed bactericidal activity. The results confirmed the potential of this class of compounds as an alternative for the development of selective antimicrobial agents. 相似文献
83.
The gamma-secretase complex, composed by presenilin, nicastrin, APH-1 and PEN-2, is involved in intramembranous proteolysis of membrane proteins, such as amyloid precursor protein or Notch. Cleavage occurs in multiple cellular compartments. Here, nicastrin mutants containing targeting signals to the endoplasmic reticulum, trans-Golgi network, lysosomes, or plasma membrane have been shown to yield active gamma-secretase complexes with different activities and specificities: wild-type and plasma membrane nicastrin complexes yielded the highest amounts of secreted amyloid-beta peptide (Abeta), predominantly Abeta40, whereas intracellular targeted mutants produced intracellular Abeta, with a comparatively higher amount of Abeta42. These results suggest that compartmental microenvironments play a role in gamma-secretase activity and specificity. 相似文献
84.
The challenge hypothesis poses that in socially monogamous vertebrates, males increase circulating testosterone in response to aggressive challenges to promote intense and persistent aggression. However, in bird species that raise only a single brood during short breeding seasons as well as those with essential male parental care, males lack the well-documented testosterone response to social challenges. We tested male behavioral and hormonal responses to social challenges in a neotropical bird species, the buff-breasted wren (Thryothorus leucotis), which is single-brooded with extensive male parental care, but in contrast to most species studied to date, has a long breeding season. We presented live female, male, and paired decoys with song playback for 30 min during pre-breeding and breeding periods. Males responded aggressively to all intruders, but male decoys elicited somewhat weaker responses overall. Responses to female decoys were most intense during pre-breeding, whereas pair decoys elicited stronger responses at breeding. Plasma testosterone concentrations did not differ between challenged and unchallenged males, or among males exposed to different decoys or during different seasons. Plasma corticosterone in pre-breeding males was higher in challenged than unchallenged males and varied positively with the duration of social challenge. Circulating dehydroepiandrosterone concentrations were similar in challenged and unchallenged males, but correlated positively with the proportion of time males spent in close proximity to the decoy. Both testosterone and corticosterone results support recent findings, suggesting that brood number and essential male care, but not breeding-season length, may be important determinants of male hormonal responsiveness during aggressive interactions. 相似文献
85.
Cui Y Costa RM Murphy GG Elgersma Y Zhu Y Gutmann DH Parada LF Mody I Silva AJ 《Cell》2008,135(3):549-560
We uncovered a role for ERK signaling in GABA release, long-term potentiation (LTP), and learning, and show that disruption of this mechanism accounts for the learning deficits in a mouse model for learning disabilities in neurofibromatosis type I (NF1). Our results demonstrate that neurofibromin modulates ERK/synapsin I-dependent GABA release, which in turn modulates hippocampal LTP and learning. An Nf1 heterozygous null mutation, which results in enhanced ERK and synapsin I phosphorylation, increased GABA release in the hippocampus, and this was reversed by pharmacological downregulation of ERK signaling. Importantly, the learning deficits associated with the Nf1 mutation were rescued by a subthreshold dose of a GABA(A) antagonist. Accordingly, Cre deletions of Nf1 showed that only those deletions involving inhibitory neurons caused hippocampal inhibition, LTP, and learning abnormalities. Importantly, our results also revealed lasting increases in GABA release triggered by learning, indicating that the mechanisms uncovered here are of general importance for learning. 相似文献
86.
Maciel-de-Freitas R Peres RC Alves F Brandolini MB 《Memórias do Instituto Oswaldo Cruz》2008,103(6):602-605
In this report, the efficiency of Adultrap under field conditions is compared to a CDC backpack aspirator and to MosquiTRAP. An urban dengue-endemic area of Rio de Janeiro was selected to evaluate the efficiency of mosquito traps in capturing Aedes aegypti females. Adultrap and aspirator captured similar numbers of Ae. aegypti females, with the former showing high specificity to gravid individuals (93.6%). A subsequent mark-release-recapture experiment was conducted to evaluate Adultrap and MosquiTRAP efficiency concomitantly. With a 6.34% recapture rate, MosquiTRAP captured a higher mean number of female Ae. aegypti per trap than Adultrap (chi2 = 14.26; df = 1; p < 0,05). However, some MosquiTRAPs (28.12%) contained immature Ae. aegypti after 18 days of exposure in the field and could be pointed as an oviposition site for female mosquitoes. Both trapping methods, designed to collect gravid Ae. aegypti females, seem to be efficient, reliable and may aid routine Ae. aegypti surveillance. 相似文献
87.
Blanco YC Farias AS Goelnitz U Lopes SC Arrais-Silva WW Carvalho BO Amino R Wunderlich G Santos LM Giorgio S Costa FT 《PloS one》2008,3(9):e3126
Background
Cerebral malaria (CM) is a syndrome characterized by neurological signs, seizures and coma. Despite the fact that CM presents similarities with cerebral stroke, few studies have focused on new supportive therapies for the disease. Hyperbaric oxygen (HBO) therapy has been successfully used in patients with numerous brain disorders such as stroke, migraine and atherosclerosis.Methodology/Principal Findings
C57BL/6 mice infected with Plasmodium berghei ANKA (PbA) were exposed to daily doses of HBO (100% O2, 3.0 ATA, 1–2 h per day) in conditions well-tolerated by humans and animals, before or after parasite establishment. Cumulative survival analyses demonstrated that HBO therapy protected 50% of PbA-infected mice and delayed CM-specific neurological signs when administrated after patent parasitemia. Pressurized oxygen therapy reduced peripheral parasitemia, expression of TNF-α, IFN-γ and IL-10 mRNA levels and percentage of γδ and αβ CD4+ and CD8+ T lymphocytes sequestered in mice brains, thus resulting in a reduction of blood-brain barrier (BBB) dysfunction and hypothermia.Conclusions/Significance
The data presented here is the first indication that HBO treatment could be used as supportive therapy, perhaps in association with neuroprotective drugs, to prevent CM clinical outcomes, including death. 相似文献88.
Adrian A. Garda Helga C. Wiederhecker Alison M. Gainsbury Gabriel C. Costa R. Alexander Pyron Gustavo H. Calazans Vieira Fernanda P. Werneck Guarino R. Colli 《Biotropica》2013,45(2):245-252
We investigate the role of ecology and phylogeny in the association between lizard abundance and microhabitat variables in an Amazon rain forest site. Using pitfall trap arrays, we collected data from 349 individuals belonging to 23 lizard species. After accounting for spatial autocorrelation and using a canonical correspondence analysis (CCA), we found that lizard captures were significantly associated with microhabitat variables, which accounted for 48 percent of the observed variation. Furthermore, a canonical phylogenetic ordination (CPO) indicated that microhabitat variables are more important in determining the distribution of lizard species than phylogenetic relationships among species. Termite nests, canopy openness, and tree circumference were strongly associated with the number of captures of certain lizard species. Our results confirm autecology studies of individual lizard species for which data are available. We suggest that maintaining heterogeneous forested microhabitats should be a central goal for sustaining a high lizard biodiversity in Amazon rain forests. 相似文献
89.
Spores belonging to 43 taxa of pteridophytes were observed from the ambient air of 11 localities in India. It is suggested that pteridophyte spores could be listed among viable particulate air pollutants, especially in the light of the earlier reports regarding their allergenicity. 相似文献
90.
Identification and aggressiveness of four isolates of Fusarium oxysporum f.sp. cubense from Latundan banana in Brazil 下载免费PDF全文