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101.
Hong E Larios F Gómez-Viquez NL Huang F Bravo G 《Journal of physiology and biochemistry》2011,67(3):427-435
The contribution of α-adrenoceptors and nitric oxide (NO) on the alterations of sympathetically mediated cardiovascular responses
after acute (AcH) and chronic (ChH) hypertension was evaluated in pithed aortic coarcted hypertensive rats. Pressor and tachycardia
response produced by electrical stimulation of preganglionic sympathetic fibers or exogenous noradrenaline (NA) were recorded
in the absence and presence of prazosin (α1-antagonist), rauwolscine (α2-antagonist), or N
G-nitro-l-arginine methyl ester (l-NAME; an inhibitor of NO synthase). Compared with age-matched sham-operated rats (Nt), the pressor response produced by electrical
stimulation or NA was smaller in AcH rats and larger in ChH rats. Prazosin caused a decrease of pressor response elicited
by electrical stimulation or NA in all groups. However, this effect was higher in ChH. Rauwolscine produced a similar increase
of sympathetically mediated pressor response in Nt and AcH rats. Nevertheless, this antagonist did not affect the sympathetically
mediated pressor response in ChH rats. In addition, rauwolscine did not affect the NA-induced pressor response in all groups.
The pressor response elicited by l-NAME was larger in all groups compared without l-NAME and in presence of l-arginine. Moreover, l-NAME in the presence of NA increased sympathetically mediated pressor response is in all groups, compared without it or in
the presence of l-arginine. Compared with Nt, basally produced NO in aortic rings was increased in AcH but decreased in ChH. Collectively,
our data suggest that decreased cardiovascular reactivity in AcH is due to an increase in basally produced NO. In ChH, enhanced
cardiovascular response appears to be associated with a decrease in produced NO and an increase in released NA from sympathetic
nerves. 相似文献
102.
Guadalupe Albarrán Kenneth E. Collins Carol H. Collins 《Journal of molecular evolution》1987,25(1):12-14
Summary Calcium carbonate labeled with carbon-14 was self-irradiated by means of the -decay of its carbon-14. A number of products containing one or two carbon atoms were identified by high performance liquid chromatography. Formic and oxalic acids were produced in relatively high yields, while glyoxylic, glycolic, and acetic acids, as well as formaldehyde and methanol, were formed in lower yields. These results support the suggestion that carbonates subjected to ionizing radiation could have been a source of carbon for organic synthesis on the primitive earth. 相似文献
103.
Aguilera-Arreola MG Hernández-Rodríguez C Zúñiga G Figueras MJ Garduño RA Castro-Escarpulli G 《Canadian journal of microbiology》2007,53(7):877-887
A comparative study of 109 Aeromonas clinical isolates belonging to the 3 species most frequently isolated from patients with diarrhea in Mexico and Spain was performed to investigate the distribution of 3 prominent toxin genes and the gene encoding flagellin of lateral flagella; 4 well-established virulence factors in the genus Aeromonas. The aerolysin-hemolysin toxin genes were the most prevalent, being present in 89% of the total isolates. The ast toxin gene was conspicuously absent from the Aeromonas caviae and Aeromonas veronii groups but was present in 91% of the Aeromonas hydrophila isolates. Both the alt toxin gene and the lafA flagellin gene also had a low incidence in A. caviae and A. veronii. Differences in the prevalence of alt and lafA were observed between isolates from Mexico and Spain, confirming genus heterogeneity according to geographic location. Carriage of multiple toxin genes was primarily restricted to A. hydrophila isolates, suggesting that A. caviae and A. veronii isolates circulating in Mexico and Spain possess a limited array of virulence genes. Enterobacterial repetitive intergenetic consensus - polymerase chain reaction showed that the Aeromonas populations sampled lack dominant clones and were genetically heterogeneous, with A. caviae being the most diverse species. Further surveys of virulence determinants in genetically heterogeneous populations of Aeromonas isolates circulating worldwide are required to enhance the understanding of their capacity to cause disease. 相似文献
104.
Gonzalez-Herrera L Castillo-Zapata I Garcia-Escalante G Pinto-Escalante D 《Birth defects research. Part A, Clinical and molecular teratology》2007,79(8):622-626
BACKGROUND: Methylenetetrahydrofolate reductase (MTHFR) of the folate metabolism pathway is a candidate gene for neural tube defects (NTDs). Frequency of the second common polymorphism, A1298C, in the MTHFR gene is not well known in Mexico. Conflicting results exist regarding the association of A1298C-MTHFR with NTDs. One explanation for this controversy might be that alleles are differently distributed among various populations. The aim of the study was to determine the frequency of the A1298C-MTHFR polymorphism and its association with NTDs in a population of Yucatan, Mexico. METHODS: Genotyping was performed by use of polymerase chain reaction with restriction fragment length polymorphisms using MbOII endonuclease (PCR-RFLPs MbOII). Allele and genotype frequencies were compared between cases with NTDs, their mothers and fathers with matched controls based on an association analysis using EpiInfo software. RESULTS: A1298C genotypes were distributed according to Hardy-Weinberg expectations for all studied groups. Frequencies of allele C and heterozygous AC genotype were significantly higher in males (p = .006 and p = .011, respectively) in control group. Significant differences were not observed between cases and controls, except in mothers of NTD cases compared with mothers of healthy offspring for both allele C and heterozygous AC genotype (p = .009 and p = .01, respectively). CONCLUSIONS: The polymorphism A1298C-MTHFR is not associated with NTDs, except for mothers, suggesting only a maternal association with having NTD-affected offspring in the Yucatan population. The frequency of allele C in the control population was 10%, which is significantly lower than in other reported control populations worldwide (p < .01). 相似文献
105.
Eva C. D. Stewart Guadalupe Bribiesca-Contreras Sergi Taboada Helena Wiklund Ascensão Ravara Ellen Pape Bart De Smet Lenka Neal Marina R. Cunha Daniel O. B. Jones Craig R. Smith Adrian G. Glover Thomas G. Dahlgren 《Diversity & distributions》2023,29(6):727-747
Aim
The abyssal Clarion-Clipperton Zone (CCZ), Pacific Ocean, is an area of commercial importance owing to the growing interest in mining high-grade polymetallic nodules at the seafloor for battery metals. Research into the spatial patterns of faunal diversity, composition, and population connectivity is needed to better understand the ecological impacts of potential resource extraction. Here, a DNA taxonomy approach is used to investigate regional-scale patterns of taxonomic and phylogenetic alpha and beta diversity, and genetic connectivity, of the dominant macrofaunal group (annelids) across a 6 million km2 region of the abyssal seafloor.Location
The abyssal seafloor (3932–5055 m depth) of the Clarion-Clipperton Zone, equatorial Pacific Ocean.Methods
We used a combination of new and published barcode data to study 1866 polychaete specimens using molecular species delimitation. Both phylogenetic and taxonomic alpha and beta diversity metrics were used to analyse spatial patterns of biodiversity. Connectivity analyses were based on haplotype distributions for a subset of the studied taxa.Results
DNA taxonomy identified 291–314 polychaete species from the COI and 16S datasets respectively. Taxonomic and phylogenetic beta diversity between sites were relatively high and mostly explained by lineage turnover. Over half of pairwise comparisons were more phylogenetically distinct than expected based on their taxonomic diversity. Connectivity analyses in abundant, broadly distributed taxa suggest an absence of genetic structuring driven by geographical location.Main Conclusions
Species diversity in abyssal Pacific polychaetes is high relative to other deep-sea regions. Results suggest that environmental filtering, where the environment selects against certain species, may play a significant role in regulating spatial patterns of biodiversity in the CCZ. A core group of widespread species have diverse haplotypes but are well connected over broad distances. Our data suggest that the high environmental and faunal heterogeneity of the CCZ should be considered in future policy decisions. 相似文献106.
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110.
Ernesto E. Ambroggio Guadalupe S. Costa Navarro Luis Benito Prez Socas Luis A. Bagatolli Andrea V. Gamarnik 《The Journal of biological chemistry》2021,297(3)
Dengue virus (DENV) and Zika virus (ZIKV) capsid proteins efficiently recruit and surround the viral RNA at the endoplasmic reticulum (ER) membrane to yield nascent viral particles. However, little is known either about the molecular mechanisms by which multiple copies of capsid proteins assemble into nucleocapsids (NCs) or how the NC is recruited and wrapped by the ER membrane during particle morphogenesis. Here, we measured relevant interactions concerning this viral process using purified DENV and ZIKV capsid proteins, membranes mimicking the ER lipid composition, and nucleic acids in in vitro conditions to understand the biophysical properties of the RNA genome encapsidation process. We found that both ZIKV and DENV capsid proteins bound to liposomes at liquid-disordered phase regions, docked exogenous membranes, and RNA molecules. Liquid–liquid phase separation is prone to occur when positively charged proteins interact with nucleic acids, which is indeed the case for the studied capsids. We characterized these liquid condensates by measuring nucleic acid partition constants and the extent of water dipolar relaxation, observing a cooperative process for the formation of the new phase that involves a distinct water organization. Our data support a new model in which capsid–RNA complexes directly bind the ER membrane, seeding the process of RNA recruitment for viral particle assembly. These results contribute to our understanding of the viral NC formation as a stable liquid–liquid phase transition, which could be relevant for dengue and Zika gemmation, opening new avenues for antiviral intervention. 相似文献