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991.
Gisela Granados-González Maricela Villagrán-SantaCruz Eric Peña-Herrera Justin L. Rheubert Kevin M. Gribbins Oswaldo Hernández-Gallegos 《Acta zoologica》2019,100(1):43-52
Gaining a deeper understanding of spermatogenic cycles within squamates has aided in our knowledge of the controls of reproduction and has bettered our understanding of reproductive phenology. One of the most studied genera of squamates, Sceloporus, is widely distributed along a latitudinal and elevational gradient in temperate, tropical, low-elevation and high-elevation habitats. Due to this wide distribution and varying habitats, Sceloporus exhibit differences in their spermatogenic activity (including both cyclical and acyclical patterns) and may be one of the most useful genera for understanding the abiotic correlations with spermatogenesis. The spermatogenic activity in Sceloporus variabilis was studied histologically (in a population that inhabits a tropical region at Los Tuxtlas, Veracruz, Mexico) and found to exhibit a unique cyclical pattern with an extended period of maximum activity (from November to July) and the absence of regression and quiescence. Furthermore, these data corroborate previous works on the spermatogenic cycles of S. variabilis despite different populations utilised. These data suggest that although abiotic factors may play a role in the timing of spermatogenesis, phylogenetic signal may be equally as important. More data concerning spermatogenic cycles in phylogenetically related taxa from differing habitats will elucidate the patterns of spermatogenic diversity. 相似文献
992.
Gryllophila cephalobulata n. sp. (Nematoda, Thelastomatidae) a parasite of the mole cricket Neocurtilla claraziana (Orthoptera, Gryllotalpidae) isolated in Buenos Aires Province, is described and illustrated. It is characterized by cuticle annulated all along the length of the body; the first ring has 4 lobules, the second one has 14 lobules, the others rings are simple, the stoma is short and has 4 small teeth, the genital papillae are arranged in 5 pairs, of which 3 pairs are preanal and 2 pairs are postanal. The tail appendage of the male is long and filiform. 相似文献
993.
Ellwood ER Diez JM Ibáñez I Primack RB Kobori H Higuchi H Silander JA 《Oecologia》2012,168(4):1161-1171
The strength and direction of phenological responses to changes in climate have been shown to vary significantly both among
species and among populations of a species, with the overall patterns not fully resolved. Here, we studied the temporal and
spatial variability associated with the response of several insect species to recent global warming. We use hierarchical models
within a model comparison framework to analyze phenological data gathered over 40 years by the Japan Meteorological Agency
on the emergence dates of 14 insect species at sites across Japan. Contrary to what has been predicted with global warming,
temporal trends of annual emergence showed a later emergence day for some species and sites over time, even though temperatures
are warming. However, when emergence data were analyzed as a function of temperature and precipitation, the overall response
pointed out an earlier emergence day with warmer conditions. The apparent contradiction between the response to temperature
and trends over time indicates that other factors, such as declining populations, may be affecting the date phenological events
are being recorded. Overall, the responses by insects were weaker than those found for plants in previous work over the same
time period in these ecosystems, suggesting the potential for ecological mismatches with deleterious effects for both suites
of species. And although temperature may be the major driver of species phenology, we should be cautious when analyzing phenological
datasets as many other factors may also be contributing to the variability in phenology. 相似文献
994.
Treatment of Biogas Produced in Anaerobic Reactors for Domestic Wastewater: Odor Control and Energy/Resource Recovery 总被引:1,自引:0,他引:1
Adalberto Noyola Juan Manuel Morgan-Sagastume Jorge E. López-Hernández 《Reviews in Environmental Science and Biotechnology》2006,5(1):93-114
Anaerobic municipal wastewater treatment in developing countries has important potential applications considering their huge
lack of sanitation infrastructure and their advantageous climatic conditions. At present, among the obstacles that this technology
encounters, odor control and biogas utilization or disposal should be properly addressed. In fact, in most of small and medium
size anaerobic municipal treatment plants, biogas is just vented, transferring pollution from water to the atmosphere, contributing
to the greenhouse gas inventory. Anaerobic municipal sewage treatment should not be considered as an energy producer, unless
a significant wastewater flow is treated. In these cases, more than half of the methane produced is dissolved and lost in
the effluent so yield values will be between 0.08 and 0.18 N m3 CH4/kg COD removed. Diverse technologies for odor control and biogas cleaning are currently available. High pollutant concentrations
may be treated with physical-chemical methods, while biological processes are used mainly for odor control to prevent negative
impacts on the treatment facilities or nearby areas. In general terms, biogas treatment is accomplished by physico-chemical
methods, scrubbing being extensively used for H2S and CO2 removal. However, dilution (venting) has been an extensive disposal method in some small- and medium-size anaerobic plants
treating municipal wastewaters. Simple technologies, such as biofilters, should be developed in order to avoid this practice,
matching with the simplicity of anaerobic wastewater treatment processes. In any case, design and specification of biogas
handling system should consider safety standards. Resource recovery can be added to anaerobic sewage treatment if methane
is used as electron donor for denitrification and nitrogen control purposes. This would result in a reduction of operational
cost and in an additional advantage for the application of anaerobic sewage treatment. In developing countries, biogas conversion
to energy may apply for the clean development mechanism (CDM) of the Kyoto Protocol. This would increase the economic feasibility
of the project through the marketing of certified emission reductions (CERs). 相似文献
995.
996.
Silveira GF Meyer F Delfraro A Mosimann AL Coluchi N Vasquez C Probst CM Báfica A Bordignon J Dos Santos CN 《Journal of virology》2011,85(11):5374-5383
A recent (2007 to 2009) dengue outbreak caused by dengue virus (DENV) in Paraguay presented unusual severe clinical outcomes associated with 50% mortality rates. Although it has been reported that inflammatory responses influence the severity of dengue virus infection (T. Pang, M. J. Cardosa, and M. G. Guzman, Immunol. Cell Biol. 85:43-45, 2007), there remains a paucity of information on virus-innate immunity interactions influencing clinical outcome. Using human dendritic cells from a major innate immune cell population as an in vitro model, we have investigated signature cytokine responses as well as infectivity-replicative profiles of DENV clinical isolates from either a nonfatal case of classical dengue fever (strain DENV3/290; isolated in Brazil in 2002) or a fatal case of dengue fever with visceral complications isolated in Paraguay in 2007 (strain DENV3/5532). Strain DENV3/5532 was found to display significantly higher replicative ability than DENV3/290 in monocyte-derived dendritic cells (mdDCs). In addition, compared to DENV3/290 results, mdDCs exposed to DENV3/5532 showed increased production of proinflammatory cytokines associated with higher rates of programmed cell death, as shown by annexin V staining. The observed phenotype was due to viral replication, and tumor necrosis factor alpha (TNF-α) appears to exert a protective effect on virus-induced mdDC apoptosis. These results suggest that the DENV3/5532 strain isolated from the fatal case replicates within human dendritic cells, modulating cell survival and synthesis of inflammatory mediators. 相似文献
997.
O Krizanová A Kiss L Záciková D Jezová 《Physiological research / Academia Scientiarum Bohemoslovaca》2001,50(5):473-480
Recent data suggest that there is interaction between peripheral angiotensin II and nitric oxide. However, sparse information is available on the mutual interaction of these two compounds in the brain. The potential intercourse of nitric oxide with brain neuropeptides needs to be substantiated by assessing its local production and gene expression of the synthesizing enzymes involved. The aim of the present study was to evaluate whether the gene expression of brain nitric oxide synthase (bNOS) is related to the sites of gene expression of different components of the rat brain renin angiotensin system (renin, angiotensin converting enzyme (ACE) or angiotensin receptors of AT1 and AT2 subtypes). The levels of corresponding mRNAs were measured and correlated in nine structures of adult rat brain (hippocampus, amygdala, septum, thalamus, hypothalamus, cortex, pons, medulla and cerebellum). As was expected, positive correlation was observed between renin and angiotensin-converting enzyme mRNAs. Moreover, a significant correlation was found between brain NO synthase and AT1 receptor mRNAs, but not with mRNA of the AT2 receptor, ACE and renin. Parallel distribution of mRNAs coding for bNOS and AT1 receptors in several rat brain structures suggests a possible interaction between brain angiotensin 11 and nitric oxide, which remains to be definitely demonstrated by other approaches. 相似文献
998.
Lázaro-Diéguez F Jiménez N Barth H Koster AJ Renau-Piqueras J Llopis JL Burger KN Egea G 《Cell motility and the cytoskeleton》2006,63(12):778-791
Here we examine the contribution of actin dynamics to the architecture and pH of the Golgi complex. To this end, we have used toxins that depolymerize (cytochalasin D, latrunculin B, mycalolide B, and Clostridium botulinum C2 toxin) or stabilize (jasplakinolide) filamentous actin. When various clonal cell lines were examined by epifluorescence microscopy, all of these actin toxins induced compaction of the Golgi complex. However, ultrastructural analysis by transmission electron microscopy and electron tomography/three-dimensional modelling of the Golgi complex showed that F-actin depolymerization first induces perforation/fragmentation and severe swelling of Golgi cisternae, which leads to a completely disorganized structure. In contrast, F-actin stabilization results only in cisternae perforation/fragmentation. Concomitantly to actin depolymerization-induced cisternae swelling and disorganization, the intra-Golgi pH significantly increased. Similar ultrastructural and Golgi pH alkalinization were observed in cells treated with the vacuolar H+ -ATPases inhibitors bafilomycin A1 and concanamycin A. Overall, these results suggest that actin filaments are implicated in the preservation of the flattened shape of Golgi cisternae. This maintenance seems to be mediated by the regulation of the state of F-actin assembly on the Golgi pH homeostasis. 相似文献
999.
Vázquez-Fernández MÁ Bermejo MR Fernández-García MI González-Riopedre G Rodríguez-Doutón MJ Maneiro M 《Journal of inorganic biochemistry》2011,105(12):1538-1547
The peroxidase and catalase activities of eighteen manganese-Schiff base complexes have been studied. A correlation between the structure of the complexes and their catalytic activity is discussed on the basis of the variety of systems studied. Complexes 1-18 have the general formulae [MnLn(D)2](X)(H2O/CH3OH)m, where Ln = L1-L13; D = H2O, CH3OH or Cl; m = 0-2.5 and X = NO3−, Cl−, ClO4−, CH3COO−, C2H5COO− or C5H11COO−. The dianionic tetradentate Schiff base ligands H2Ln are the result of the condensation of different substituted (OMe-, OEt-, Br-, Cl-) hydroxybenzaldehyde with diverse diamines (1,2-diaminoethane for H2L1-H2L2; 1,2-diamino-2-methylethane for H2L3-H2L4; 1,2-diamino-2,2-dimethylethane for H2L5; 1,2-diphenylenediamine for H2L6-H2L7; 1,3-diaminopropane for H2L8-H2L11; 1,3-diamino-2,2-dimethylpropane for H2L12-H2L13). The new Mn(III) complexes [MnL1(H2O)Cl](H2O)2.5 (2), [MnL2(H2O)2](NO3)(H2O) (4), [MnL6(H2O)2][MnL6(CH3OH)(H2O)](NO3)2(CH3OH) (8), [MnL6(H2O)(OAc)](H2O) (9) and [MnL7(H2O)2](NO3)(CH3OH)2 (12) were isolated and characterised by elemental analysis, magnetic susceptibility and conductivity measurements, redox studies, ESI spectrometry and UV, IR, paramagnetic 1H NMR, and EPR spectroscopies. X-ray crystallographic studies of these complexes and of the ligand H2L6 are also reported. The crystal structures of the rest of the complexes have been previously published and herein we have only revised their study by those techniques still not reported (EPR and 1H NMR for some of these compounds) and which help to establish their structures in solution. Complexes 1-12 behave as more efficient mimics of peroxidase or catalase in contrast with 13-18. The analysis between the catalytic activity and the structure of the compounds emphasises the significance of the existence of a vacant or a labile position in the coordination sphere of the catalyst. 相似文献
1000.
Crocenzi FA Mottino AD Cao J Veggi LM Pozzi EJ Vore M Coleman R Roma MG 《American journal of physiology. Gastrointestinal and liver physiology》2003,285(2):G449-G459
Endocytic internalization of the multidrug resistance-associated protein 2 (Mrp2) was previously suggested to be involved in estradiol-17beta-D-glucuronide (E217G)-induced cholestasis. Here we evaluated in the rat whether a similar phenomenon occurs with the bile salt export pump (Bsep) and the ability of DBcAMP to prevent it. E217G (15 micromol/kg i.v.) impaired bile salt (BS) output and induced Bsep internalization, as assessed by confocal microscopy and Western blotting. Neither cholestasis nor Bsep internalization occurred in TR- rats lacking Mrp2. DBcAMP (20 micromol/kg i.v.) partially prevented the decrease in bile flow and BS output and substantially prevented E217G-induced Bsep internalization. In hepatocyte couplets, E217G (50 microM) diminished canalicular accumulation of a fluorescent BS and decreased Bsep-associated fluorescence in the canalicular membrane; DBcAMP (10 microM) fully prevented both effects. In conclusion, our results suggest that changes in Bsep localization are involved in E217G-induced impairment of bile flow and BS transport and that DBcAMP prevents this effect by stimulating insertion of canalicular transporter-containing vesicles. Mrp2 is required for E217G to induce its harmful effect. 相似文献