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1.
V. Carré‐Missio F.A. Rodrigues D.A. Schurt R.S. Resende N.F.A. Souza D.C. Rezende W.R. Moreira L. Zambolim 《The Annals of applied biology》2014,164(3):396-403
Coffee leaf rust, caused by Hemileia vastatrix, is the most devastating disease of coffee. Since limited information is available in the literature on silicon (Si) affecting plant diseases in coffee, this study was designed to investigate foliar application of potassium silicate (PS), a source of soluble (Si), on infection process of coffee leaf rust at the microscopic level. The foliar Si concentration for plants sprayed with water and PS has no significant difference (0.24 and 0.30 dag kg?1, respectively). X‐ray microanalysis indicated that the deposition of Si on the leaves of the plants that were sprayed with PS was greater in comparison to the leaf samples from the plants sprayed with water. Rust severity on leaves of plants sprayed with water or sprayed with PS reached 44% and 32%, respectively, at 36 days after inoculation (dai). Plates of polymerised PS were observed on the leaf surfaces of the plants sprayed with the product, in contrast to its absence on the leaf surfaces of plants sprayed with water. At 36 dai, a greater number of uredia were observed on the leaf surfaces of plants sprayed with water in comparison to the leaf surfaces of plants sprayed with PS. On fractured leaf tissues that were sprayed with PS, less fungal colonisation was observed in comparison to the leaves of plants sprayed with water. In conclusion, the results of this study suggest that the effect of foliar‐applied Si on the control of the coffee leaf rust development may be attributed to the physical role of the polymerised PS, its osmotic effect against urediniospores germination, or both. 相似文献
2.
Trypanosoma cruzi: identification of specific epimastigote antigens by human immune sera 总被引:2,自引:0,他引:2
M G Morgado J Ivo-dos-Santos R T Pinho E Argüelles J M Rezende B Galv?o-Castro 《Memórias do Instituto Oswaldo Cruz》1989,84(3):309-314
Soluble antigens from epimastigotes of Trypanosoma cruzi were analyzed by western blot in terms of their reactivity with sera from patients with Chagas' disease. In addition, sera from patients with visceral (AVL) and tegumental leishmaniasis (ATL) were also tested in order to identify cross-reactivities with Trypanosoma cruzi antigens. Twenty eight polypeptides with molecular weights ranging from 14 kDa to 113 kDa were identified with sera from Chagas' disease patients. An extensive cross-reactivity was observed when sera from human visceral leishmaniasis were used, while only a slight cross-reaction was observed with sera from tegumental leishmaniasis. On the other hand, 10 polypeptides specifically reacting with sera from Chagas' disease patients were identified. Among them, the antigens with molecular weights of 46 kDa and 25 kDa reacted with all sera tested and may be good candidates for specific immunodiagnosis of Chagas' disease. 相似文献
3.
Hardies SC; Martin SL; Voliva CF; Hutchison CA d; Edgell MH 《Molecular biology and evolution》1986,3(2):109-125
4.
Andrés N. Molina José M. Pulgar Enrico L. Rezende Mauricio J. Carter 《Global Change Biology》2023,29(1):179-188
Global warming is affecting the Antarctic continent in complex ways. Because Antarctic organisms are specialized to living in the cold, they are vulnerable to increasing temperatures, although quantitative analyses of this issue are currently lacking. Here we compiled a total of 184 estimates of heat tolerance belonging to 39 marine species and quantified how survival is affected concomitantly by the intensity and duration of thermal stress. Species exhibit thermal limits displaced toward colder temperatures, with contrasting strategies between arthropods and fish that exhibit low tolerance to acute heat challenges, and brachiopods, echinoderms, and molluscs that tend to be more sensitive to chronic exposure. These differences might be associated with mobility. A dynamic mortality model suggests that Antarctic organisms already encounter temperatures that might be physiologically stressful and indicate that these ecological communities are indeed vulnerable to ongoing rising temperatures. 相似文献
5.
Paulino Bambi Alan M. Tonin Renan de Souza Rezende Fernando Carvalho Vieira Fernanda Gabriela Graciano Miranda Luz Boyero José F. Gonçalves Júnior 《Biotropica》2023,55(1):40-52
Riparian forests play an important role in stream ecosystems, as they support biodiversity, reduce water erosion, and provide litter that fuels aquatic biota. However, they are affected by great array of anthropogenic threats (e.g., fire, logging, and organic pollution), which alter species composition and their physical structure. Although forest recovery after disturbance such as logging can take decades, the legacy of forest clear-cut logging on key processes in tropical riparian ecosystems is mostly unknown. Here, we investigated how litter inputs (leaves, twigs, and reproductive parts) and storage, key processes for carbon and nutrient recycling and for forest and stream biota, are influenced by riparian vegetation undergoing succession (after 28 years from logging) through the comparison of reference and logged forest sites in the Cerrado biome. Litterfall was overall similar between forest types, but litterfall of twigs was twofold higher at logged than reference sites. Similarly, litter inputs from the bank to the stream (i.e., lateral inputs) and streambed storage were 50–60% higher at logged than reference sites. The higher litterfall observed in logged forests could be related to higher proportion of tree species that are characteristic of primary and secondary successional stages, including fast-growing and liana species, which often are more productive and common in anthropogenic areas. Our results showed that the legacy impact of clear-cut logging, even if residual woody vegetation is maintained in riparian buffers, can shift the type, quantity, and seasonality of litter subsidies to tropical streams. This knowledge should be considered within the context of management and conservation of communities and ecosystem processes in the forest-stream interfaces. 相似文献
6.
A major difference between the divergence patterns within the lines-1 families in mice and voles 总被引:3,自引:0,他引:3
Vanlerberghe F; Bonhomme F; Hutchison CA d; Edgell MH 《Molecular biology and evolution》1993,10(4):719-731
L1 retroposons are represented in mice by subfamilies of interspersed
sequences of varied abundance. Previous analyses have indicated that
subfamilies are generated by duplicative transposition of a small number of
members of the L1 family, the progeny of which then become a major
component of the murine L1 population, and are not due to any active
processes generating homology within preexisting groups of elements in a
particular species. In mice, more than a third of the L1 elements belong to
a clade that became active approximately 5 Mya and whose elements are >
or = 95% identical. We have collected sequence information from 13 L1
elements isolated from two species of voles (Rodentia: Microtinae: Microtus
and Arvicola) and have found that divergence within the vole L1 population
is quite different from that in mice, in that there is no abundant
subfamily of homologous elements. Individual L1 elements from voles are
very divergent from one another and belong to a clade that began a period
of elevated duplicative transposition approximately 13 Mya. Sequence
analyses of portions of these divergent L1 elements (approximately 250 bp
each) gave no evidence for concerted evolution having acted on the vole L1
elements since the split of the two vole lineages approximately 3.5 Mya;
that is, the observed interspecific divergence (6.7%-24.7%) is not larger
than the intraspecific divergence (7.9%-27.2%), and phylogenetic analyses
showed no clustering into Arvicola and Microtus clades.
相似文献
7.
Sulfate reduction and S-oxidation in a moorland pool sediment 总被引:3,自引:2,他引:1
In an oligotrophic moorland pool in The Netherlands, S cycling near the sediment/water boundary was investigated by measuring (1) SO4
2– reduction rates in the sediment, (2) depletion of SO4
2– in the overlying water column and (3) release of35S from the sediment into the water column. Two locations differing in sediment type (highly organic and sandy) were compared, with respect to reduction rates and depletion of SO4
2– in the overlying water.Sulfate reduction rates in sediments of an oligotrophic moorland pool were estimated by diagenetic modelling and whole core35SO4
2– injection. Rates of SO4
2– consumption in the overlying water were estimated by changes in SO4
2– concentration over time in in situ enclosures. Reduction rates ranged from 0.27–11.2 mmol m–2 d–1. Rates of SO4
2– uptake from the enclosed water column varied from –0.5, –0.3 mmol m–2 d–1 (November) to 0.43–1.81 mmol m–2 d–1 (July, August and April). Maximum rates of oxidation to SO4
2– in July 1990 estimated by combination of SO4
2– reduction rates and rates of in situ SO4
2– uptake in the enclosed water column were 10.3 and 10.5 mmol m–2 d–1 at an organic rich and at a sandy site respectively.Experiments with35S2– and35SO4
2– tracer suggested (1) a rapid formation of organically bound S from dissimilatory reduced SO4
2– and (2) the presence of mainly non SO4
2–-S derived from reduced S transported from the sediment into the overlying water. A35S2– tracer experiment showed that about 7% of35S2– injected at 1 cm depth in a sediment core was recovered in the overlying water column.Sulfate reduction rates in sediments with higher volumetric mass fraction of organic matter did not significantly differ from those in sediments with a lower mass fraction of organic matter.Corresponding author 相似文献
8.
Genetic tailoring of N-linked oligosaccharides: the role of glucose residues in glycoprotein processing of Saccharomyces cerevisiae in vivo 总被引:1,自引:0,他引:1
In higher eukaryotes a quality control system monitoring the folding state
of glycoproteins is located in the ER and is composed of the proteins
calnexin, calreticulin, glucosidase II, and UDP-glucose: glycoprotein
glucosyltransferase. It is believed that the innermost glucose residue of
the N- linked oligosaccharide of a glycoprotein serves as a tag in this
control system and therefore performs an important function in the protein
folding pathway. To address this function, we constructed Saccharomyces
cerevisiae strains which contain nonglucosylated (G0), monoglucosylated
(G1), or diglucosylated (G2) glycoproteins in the ER and used these strains
to study the role of glucose residues in the ER processing of
glycoproteins. These alterations of the oligosaccharide structure did not
result in a growth phenotype, but the induction of the unfolded protein
response upon treatment with DTT was much higher in G0 and G2 strains as
compared to wild-type and G1 strains. Our results provide in vivo evidence
that the G1 oligosaccharide is an active oligosaccharide structure in the
ER glycoprotein processing pathway of S.cerevisiae. Furthermore, by
analyzing N- linked oligosaccharides of the constructed strains we can
directly show that no general glycoprotein glucosyltransferase exists in S.
cerevisiae.
相似文献
9.
人肺腺癌细胞分化相关基因cDNAs的克隆 总被引:2,自引:0,他引:2
在用10-5 mol/L全反式维甲酸(RA)诱导人肺腺癌细胞系GLC-82分化的基础上,以M13噬菌粒pSPORT1为载体,应用定向克隆技术,分别构建了未经RA诱导和RA诱导1d及4d细胞的3个cDNA文库.以含重组子的诱导文库单链DNA为靶标(Target)同未诱导文库的cDNA驱除子(Driver)进行消减杂交,富集RA特异性单链DNA,将富集的单链DNA回复为双链后转化感受态菌,建立细胞诱导分化过程中活化表达基因的cDNA消减文库,得到124个cDNA消减克隆.经同源性分析和与文库总cDNA作Southern印迹杂交,进而与RA诱导前后细胞的RNA作Northern印迹杂交,筛选出2个(RA5,RA28)诱导后呈早期瞬时表达和1个(RA42)呈早期并持续表达的cDNA克隆,cDNA全长分别为1.8,1.5和0.7kb.序列测定及初步功能分析结果表明,RA5,RA28和RA42这3个首次报道的序列,可能是人肺腺癌细胞分化相关基因的cDNA克隆. 相似文献
10.
The carbon (C) concentration and flux, as dissolved organic carbon (DOC), particulate organic carbon (POC) and macrodetritus (MD), were quantified through 4 tidal cycles in a mangrove tidal creek in Southeastern Brazil. DOC was the major fraction of the total C concentration, accounting for 68 and 61% of the total C concentration during ebb and flood periods respectively. Concentrations of DOC (Ebb = 3.41 +/- 0.57 mgC.L-1 and Flood = 3.55 +/- 0.76 mgC.L-1) and POC (Ebb = 1.73 +/- 0.99 mgC.L-1 and Flood = 1.28 +/- 0.45 mgC.L-1) were relatively similar during the four tidal cycles. Macrodetritus presented a wide variation with concentration peaks probably related to external forces, such as winds, which enrich the ebb flow with leaf litter. DOC and POC fluxes depended primarily on tidal and net water fluxes, whereas MD fluxes were not. The magnitude of the DOC and POC fluxes varied with the area flooded at high tide, but not the MD fluxes. DOC was the major form of carbon export to Sepetiba Bay. During the four tidal cycles, the forest exported a total of 1.2 kg of organic carbon per ha, mostly as DOC (60%), followed by POC (22%) and MD (18%). 相似文献