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131.
Photosynthetic response of two tropical liana species grown under different irradiances 总被引:1,自引:0,他引:1
We investigated the characteristics of gaseous exchanges and chlorophyll a fluorescence under different irradiances in two liana species Canavalia parviflora Benth. (Fabaceae) and Gouania virgata Reissk (Rhamnaceae), both of a semi-deciduous tropical forest of Southeast Brazil. We used cultivated plants growing under
irradiances of 100, 40, 10, and 1.5 % of the photosynthetic photon flux density (PPFD). Higher net photosynthetic rates (P
N) were observed during early morning under full sunlight. After this, reduced P
N values were recorded due to pronounced stomatal closure. In Canavalia, the gas exchange responses diminished concomitant with reduced irradiance. Gouania exhibited a narrower range of response, with high P
N values even at 10 % PPFD. Marked reduction of the effective photochemical yield (ΔF/Fm’) near midday was observed, followed by increases in the non-photochemical quenching for both species under full sunlight.
Despite the common occurrence of these species in open areas of the forest, both were able to maintain relatively high P
N in shaded environments. We suggest that lianas present an intermediate physiological behaviour between shade and non-shade
tolerant species. 相似文献
132.
Andréa?BialetzkiEmail author Keshiyu?Nakatani Paulo?Vanderlei?Sanches Gilmar?Baumgartner Luiz?Carlos?Gomes 《Environmental Biology of Fishes》2005,73(1):37-47
Synopsis We sampled the Baía River (Mato Grosso do Sul State, Brazil) monthly, to survey taxonomic composition and temporal and spatial distribution of fish larvae. The ichthyoplankton was mainly composed by larvae of small and medium sized sedentary species and it was numerically dominated by six taxa: Plagioscion squamosissimus, Hypophthalmus edentatus, Hoplias aff. malabaricus, Bryconamericus stramineus, Serrasalmus spp. and Catathyridium jenynsii. These taxa present distinct temporal and spatial occurrence patterns: H. edentatus, B. stramineus and C. jenynsii are abundant between September and March in lentic areas; H. aff. malabaricus and Serrasalmus spp. were caught between October and February in lotic areas; whereas P. squamosissimus occurs in all sampled areas, with peak of capture in January. Hypophthalmus edentatus, H. aff. malabaricus, Serrasalmus spp. and B. stramineus were the taxa that most contributed to structure the assemblages temporally and spatially, and their abundances were influenced by the interaction of several environmental variables. 相似文献
133.
EG Smirnova GS Muromtsev AV Osipenko EE Khavkin LS Yaguzhinsky 《Biochemistry. Biokhimii?a》1998,63(9):1021-1028
Activation of highly specific biochemical processes by simple chemical agents is demonstrated for morphogenesis (anlage and development of female gametophyte in cereal) and mitosis (in cell cultures and animal and plant tissues). The effects of these agents are tissue-specific. Structure--activity relationship is analyzed in this group of compounds. Thus, the phenomenon reveals the exact pathways of the influence of allelopathic and anthropogenic chemical agents on evolution of plant biocenoses. 相似文献
134.
Sialylation is a biosynthetic process occurring in the trans compartments
of the Golgi apparatus. Corresponding evidence is based on localization and
biochemical studies of alpha2, 6(N)-sialyltransferase (ST6Gal I) as
previously reported. Here we describe generation and characterization of
polyclonal antibodies to recombinant rat alpha2,3(N)-sialyltransferase
(ST3Gal III) expressed as a soluble enzyme in Sf9 cells or as a
beta-galactosidase-human-ST3Gal III fusion- protein from E.coli ,
respectively. These antibodies were used to localize ST3Gal III by
immunofluorescence in various cell lines and rat kidney tissue sections. In
transiently transfected COS cells the antibodies directed to soluble
sialyltransferase or the sialyltransferase portion of the fusion-protein
only recognized the recombinant antigen retained in the endoplasmic
reticulum. However, an antibody fraction crossreactive with
beta-galactosidase recognized natively expressed ST3Gal III which was found
to be colocalized with beta1, 4-galactosyltransferase in the Golgi
apparatus of several cultured cell lines. Antibodies affinity purified on
the beta- galactosidase-ST3Gal III fusion-protein column derived from both
antisera have then been used to localize the enzyme in perfusion-fixed rat
kidney sections. We found strong staining of the Golgi apparatus of tubular
epithelia and a brush-border-associated staining which colocalized with
cytochemical staining of the H+ATPase. This subcellular localization was
not observed for ST6Gal I which localized to the Golgi apparatus. These
data show colocalization in the Golgi apparatus and different post-Golgi
distributions of the two sialyltransferases.
相似文献
135.
136.
Bruna Larissa Maganhe Laura de Oliveira Camilo Rodrigo E. Kurokawa Hugo Gallo Neto Eduardo Gomes Sanches 《Journal of fish biology》2023,102(1):119-127
Endemic to the south-west Atlantic Ocean, the shortnose guitarfish (Zapteryx brevirostris) is a small species, classified as endangered by the IUCN. Although reproduction in captivity has been successful for some species, a range of factors can limit the success of captive breeding programmes for elasmobranchs. In Brazil, the Ubatuba Aquarium was the first public aquarium to reproduce small-sized elasmobranchs. Since 2018, at least five parturition events have been recorded for Z. brevirostris at the institution. From a total of 13 live neonates that rearing was attempted, the mean ± standard error of weight, total length (TL) and disc width at birth were 17.47 ± 1.6 g, 13.25 ± 0.7 cm and 6.53 ± 0.2 cm, respectively. The mean weight as well as mean TL were higher for females at all births, with 26.15 g and 15.07 cm for females in comparison with 17.09 g and 13.94 cm for males. Considering the increasing risk of extinction that the species is facing, age and growth studies are fundamental for the success of conservation, improving the knowledge of Z. brevirostris life cycle so that a more efficient and sustainable management can be carried out. This study provides important data, as well as directions for captive breeding of the species. 相似文献
137.
Summary The selected yeast strains were examined for their ability to grow, to retain cell viability and to ferment diluted sugar cane juice (15 % total sugar, w/v) to ethanol at 40°C. The degree of agitation (aeration) affects the thermotolerance while the method used for isolation of the strains appears to have no significant effect. The yeast isolated are aerobically fermentative with increased levels of fermentation and growth resulting from agitation (aeration), the exact level of these increases being dependent on the strain used. 相似文献
138.
Flávio Augusto Sanches Politi Amauri Alves Souza Júnior Rafaela Regina Fantatto Rosemeire Cristina Linhari Rodrigues Pietro Waldomiro Barioni Júnior Márcio Dias Rabelo Humberto Ribeiro Bizzo Ana Carolina de Souza Chagas Maysa Furlan 《化学与生物多样性》2018,15(2)
Sheep breeding has suffered economic losses due to parasitism by gastrointestinal nematodes, particularly Haemonchus contortus. The use of natural products, specifically Tagetes patula, has been suggested as an alternative method of combatting this issue. Chemical analyses of the extracts of this species described in the literature report the presence of important classes of secondary metabolites such as thiophenes, flavonoids, alkaloids, and benzofurans, some of which were identified and isolated in this study. The aim of this work was to test the effect of the essential oil (EO) and the ethanolic extract of the aerial parts (TpEtOH) of T. patula on eggs and larvae of H. contortus, through an egg hatch test (EHT) and a larval development test (LDT). In the EHT, the EO showed 100% inhibition at 0.75 mg mL?1 (LC50 = 0.0780 mg mL?1), and the TpEtOH showed 100% inhibition at 100 mg mL?1 (LC50 = 12.8 mg mL?1). In the LDT, the EO showed 100% inhibition at 0.375 mg mL?1 (LC50 = 0.0400 mg mL?1), and the TpEtOH showed 100% inhibition at 1.56 mg mL?1 (LC50 = 0.340 mg mL?1). Compared to available literature data, the results presented here suggest that the crude extracts of T. patula have substantial potential for controlling this nematode by interrupting its life cycle and/or preventing it from reaching the infective stage. 相似文献
139.
Hepatocellular carcinoma in a free‐living marmoset (Callithrix sp.) with concomitant biliary trematodiasis 下载免费PDF全文
J. Díaz‐Delgado T. C. Sanches C. dos Santos‐Cirqueira A. A. C. Coimbra J. M. Guerra A. Joppert C. Di Loretto M. B. Rizardi M. Sansone F. O. Nagamori P. S. Gonçalves R. Ressio S. Iglezias N. C. C. A. Fernandes C. Kanamura K. R. Groch J. L. Catão‐Dias 《Journal of medical primatology》2018,47(2):128-131
Hepatocellular carcinoma (HCC) is rare in New World primates. We report the gross, microscopical, and immunocytochemical features of a spontaneous HCC in a free‐living marmoset (Callithrix sp.). Hepatitis B and C virus and aflatoxin immunohistochemistry were negative; however, concomitant intra‐ and extrahepatic biliary trematodiasis could have played a role. 相似文献
140.
Structural characterization of B and non-B subtypes of HIV-protease: insights into the natural susceptibility to drug resistance development 总被引:1,自引:0,他引:1
Sanches M Krauchenco S Martins NH Gustchina A Wlodawer A Polikarpov I 《Journal of molecular biology》2007,369(4):1029-1040
Although a majority of HIV-1 infections in Brazil are caused by the subtype B virus (also prevalent in the United States and Western Europe), viral subtypes F and C are also found very frequently. Genomic differences between the subtypes give rise to sequence variations in the encoded proteins, including the HIV-1 protease. The current anti-HIV drugs have been developed primarily against subtype B and the effects arising from the combination of drug-resistance mutations with the naturally existing polymorphisms in non-B HIV-1 subtypes are only beginning to be elucidated. To gain more insights into the structure and function of different variants of HIV proteases, we have determined a 2.1 A structure of the native subtype F HIV-1 protease (PR) in complex with the protease inhibitor TL-3. We have also solved crystal structures of two multi-drug resistant mutant HIV PRs in complex with TL-3, from subtype B (Bmut) carrying the primary mutations V82A and L90M, and from subtype F (Fmut) carrying the primary mutation V82A plus the secondary mutation M36I, at 1.75 A and 2.8 A resolution, respectively. The proteases Bmut, Fwt and Fmut exhibit sevenfold, threefold, and 54-fold resistance to TL-3, respectively. In addition, the structure of subtype B wild type HIV-PR in complex with TL-3 has been redetermined in space group P6(1), consistent with the other three structures. Our results show that the primary mutation V82A causes the known effect of collapsing the S1/S1' pockets that ultimately lead to the reduced inhibitory effect of TL-3. Our results further indicate that two naturally occurring polymorphic substitutions in subtype F and other non-B HIV proteases, M36I and L89M, may lead to early development of drug resistance in patients infected with non-B HIV subtypes. 相似文献