We compared male-reproductive-tract polypeptides of Drosophila melanogaster
and D. simulans by using two-dimensional gel electrophoresis. Approximately
64% of male-reproductive-tract polypeptides were identical between two
randomly chosen isofemale lines from these two species, compared with 83%
identity for third-instar imaginal wing-disc polypeptides. Qualitatively
similar differences were found between reproductive tracts and imaginal
discs when D. sechellia was compared with D. melanogaster and with D.
simulans. When genic polymorphism was taken into account, approximately 10%
of male- reproductive-tract polypeptides were apparently fixed for
different alleles between D. melanogaster and D. simulans; this proportion
is the same as that found for soluble enzymes by one-dimensional gel
electrophoresis. Strikingly, approximately 20% of male-reproductive- tract
polypeptides of either D. melanogaster or D. simulans had no detectable
homologue in the other species. We propose that proteins of the Drosophila
male reproductive tract may have diverged more extensively between species
than have other types of proteins and that much of this divergence may
involve large changes in levels of polypeptide expression.
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Several indexes are used to determine the iron nutritional status of plants, but their effectiveness depends either on the
plant growth conditions in natural environments or on the assay conditions. This research was conducted to test different
indexes of the iron nutritional status of a hydroponic strawberry culture where treatments mainly differed in the source of
the iron applied: Fe-EDTA, Fe-EDDHA and Fe-polyflavonoid. Macro and micronutrient concentrations in the nutrient solutions,
leaf and vascular tissues were measured. Fe concentration in the nutrient solution during the course of the experiment was
considered in relation to the stability of the different chelates. Both Fe concentration and total Fe content of leaves reflected
the effect of the treatments; Fe/Mn ratio was significant as a diagnosis index. Other element ratios as P/Fe and K/Ca are
not well related with the iron nutrition symptoms observed. Fe2+ concentration measured in leaves was not directly affected by the different chelate treatments. 相似文献
Post-translational methylation of proteins, which occurs in arginines and lysines, modulates several biological processes at different levels of cell signaling. Recently, methylation has been demonstrated in the regulation beyond histones, for example, in the dynamics of protein-protein and protein-nucleic acid interactions. However, the presence and role of non-histone methylation in Trypanosoma cruzi, the etiologic agent of Chagas disease, has not yet been elucidated. Here, we applied mass spectrometry-based-proteomics (LC-MS/MS) to profile the methylproteome of T. cruzi epimastigotes, describing a total of 1252 methyl sites in 824 proteins. Functional enrichment and protein-protein interaction analysis show that protein methylation impacts important biological processes of the parasite, such as translation, RNA and DNA binding, amino acid, and carbohydrate metabolism. In addition, 171 of the methylated proteins were previously reported to bear phosphorylation sites in T. cruzi, including flagellar proteins and RNA binding proteins, indicating that there may be an interplay between these different modifications in non-histone proteins. Our results show that a broad spectrum of functions is affected by methylation in T. cruzi, indicating its potential to impact important processes in the biology of the parasite and other trypanosomes. 相似文献
Fuente de Piedra is a shallow, temporary saline lake whoseseasonal behavior is strongly dependent on the annual hydrologicalbudget. In this study, we outline the characteristics of Fuente dePiedra Lake for two years that had different hydrological budgets.The high precipitations in 1989–90 caused the lake not to dry asusual, and decreased both salinity and the amplitude of changes.There were also differences in nutrient dynamics, with generallylower concentrations of soluble reactive phosphorus and ammonium,whereas in the more humid year nitrate showed a distinct maximum inwinter. Winter bloom chlorophyll a concentrations were alsomuch higher in 1989–90 (>600 g l-1) but there wasalso a winter productive phase that was presumably poorly coupledwith consumption processes that predominate in spring. Planktonicassemblages were different between years. Highly halotolerantphytoplankton species (Dunaliella salina and D. viridis) became scarcer, and especially two previouslyunrecorded diatoms (Cyclotella sp. and Chaetoceros sp.)became dominant in the bloom time in the wet year. The speciesrichness of the zooplankton increased in the wet year, with newspecies appearing that were not collected during 1987–88(Branchinectella media, Daphnia mediterranea, Macrothrix sp.,Arctodiaptomus salinus, Cyclops sp., Sigara sp...).There was also a much higher development of macrophytes (Ruppiadrepanensis, Althenia orientalis, Lamprothamnium papulosum)and bird populations, especially flamingoes (Phoenicopterusruber).Important interannual variations in this sort of system pointto the need for long term studies to observe the whole range ofstates that define the lake as an entity. 相似文献
Neurochemical Research - Gamma-decanolactone (GD) has been shown to reduce epileptic behavior in different models, inflammatory decreasing, oxidative stress, and genotoxic parameters. This study... 相似文献
Inter-basin water transfer (IBWT) involves the transport of water from one geographically distinct basin to another to balance the distribution of water resources. Although the socio-economic benefits of implementing these projects are well recognized, little is known about the subsequent effects on the water quality of the receiving systems. We evaluated the effects of an IBWT on the water quality of three receiving reservoirs of an intermittent river in a semi-arid region. We compared the similarity among the reservoirs before and after the IBWT to assess how the reservoirs responded to the introduction of water. Although the last two reservoirs that have received water have become similar in terms of physical and chemical characteristics and algal biomass (chlorophyll-a), the first reservoir has not. The IBWT resulted in an improvement in the water quality of the first reservoir but a decrease in the water quality of the two successive reservoirs, along with a significant increase in algal biomass. Long river sections located upstream that were dry at the time of IBWT probably contributed nutrients to the water as it moved downstream and into the reservoirs. Significant differences in the water quality were observed for different sampling months after the IBWT, but not for different sampling depths. Before the IBWT, the predictor variables for algal biomass were basically transparency and non-algal turbidity, with which it established a positive relationship. After IBWT, however, algal biomass also showed a positive relationship with pH and temperature. We conclude that IBWT affects the water quality of receiving reservoirs and that the responses are reservoir specific. IBWT also increases the complexity of the correlations of physical and chemical variables with algal biomass.
The stimulation by Mg2+, Na+, K+, NH4+, and ATP of (Na+, K+)-ATPase activity in a gill microsomal fraction from the freshwater prawn Macrobrachium rosenbergii was examined. Immunofluorescence labeling revealed that the (Na+, K+)-ATPase α-subunit is distributed predominantly within the intralamellar septum, while Western blotting revealed a single α-subunit isoform of about 108 kDa Mr. Under saturating Mg2+, Na+, and K+ concentrations, the enzyme hydrolyzed ATP, obeying cooperative kinetics with VM = 115.0 ± 2.3 U mg?1, K0.5 = 0.10 ± 0.01 mmol L?1. Stimulation by Na+ (VM = 110.0 ± 3.3 U mg?1, K0.5 = 1.30 ± 0.03 mmol L?1), Mg2+ (VM = 115.0 ± 4.6 U mg?1, K0.5 = 0.96 ± 0.03 mmol L?1), NH4+ (VM = 141.0 ± 5.6 U mg?1, K0.5 = 1.90 ± 0.04 mmol L?1), and K+ (VM = 120.0 ± 2.4 U mg?1, KM = 2.74 ± 0.08 mmol L?1) followed single saturation curves and, except for K+, exhibited site–site interaction kinetics. Ouabain inhibited ATPase activity by around 73 % with KI = 12.4 ± 1.3 mol L?1. Complementary inhibition studies suggest the presence of F0F1–, Na+-, or K+-ATPases, but not V(H+)- or Ca2+-ATPases, in the gill microsomal preparation. K+ and NH4+ synergistically stimulated enzyme activity (≈25 %), suggesting that these ions bind to different sites on the molecule. We propose a mechanism for the stimulation by both NH4+, and K+ of the gill enzyme. 相似文献
Polymorphisms in chemokine receptors play an important role in the progression of
cervical intraepithelial neoplasia (CIN) to cervical cancer (CC). Our study examined
the association of CCR2-64I (rs1799864) andCCR5-Δ32
(rs333) polymorphisms with susceptibility to develop cervical lesion (CIN and CC) in
a Brazilian population. The genotyping of 139 women with cervical lesions and 151
women without cervical lesions for the CCR2-64I and
CCR5-Δ32 polymorphisms were performed using polymerase chain
reaction-restriction fragment length polymorphism. The individuals carrying
heterozygous or homozygous genotypes (GA+AA) for CCR2-64I
polymorphisms seem to be at lower risk for cervical lesion [odds ratio (OR) = 0.37, p
= 0.0008)]. The same was observed for the A allele (OR = 0.39, p = 0.0002), while no
association was detected (p > 0.05) with CCR5-Δ32 polymorphism.
Regarding the human papillomavirus (HPV) type, patients carrying the
CCR2-64Ipolymorphism were protected against infection by HPV type
16 (OR = 0.35, p = 0.0184). In summary, our study showed a protective effect
ofCCR2-64I rs1799864 polymorphism against the development of
cervical lesions (CIN and CC) and in the susceptibility of HPV 16 infection. 相似文献
This study investigated the use of woody plants by a rural community in an area of dry land Caatinga vegetation in northeastern Brazil. Information was obtained concerning this woody species with a diameter that is equal to or greater than 3 centimeters (cm) at soil level surveyed in 100 sample plots totaling 1 hectare (ha). The following question is the hypothesis we tested. Is a plant’s relative importance (as measured by its use value) related to its “apparency,” as measured by its abundance and ecological dominance? “Apparency” explains the use value of plants in four categories: medicinal, construction, fuel, and technology. The most important uses of woody plants are related to harvesting for energy and construction purposes. 相似文献