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101.
Schistosoma mansoni: alterations in total protein and hemoglobin in the hemolymph of infected Biomphalaria glabrata 总被引:1,自引:0,他引:1
The total protein concentrations in the hemolymph of noninfected Biomphalaria glabrata and those parasitized by Schistosoma mansoni have been compared. That of the former, averaging 1.42 g/100 ml, is greater than that of the latter which averages 0.96 g/100 ml. The hemoglobin concentrations in the two categories of snails have also been compared and that in noninfected specimens, averaging 0.956 g/100 ml, is higher than that in infected snails which average 0.650 g/100 ml. It has also been ascertained that both the total protein and hemoglobin concentrations in snails of different sizes vary; specimens measuring between 10 and 16 mm in diameter tend to include more hemoglobin than larger ones. On the other hand, larger snails tend to include greater total protein concentrations. 相似文献
102.
F.-Y. Jia M. D. Greenfield 《Proceedings. Biological sciences / The Royal Society》1997,264(1384):1057
Female lesser wax moths (Achroia grisella) choose males based on characters of their ultrasonic advertisement signals. Because a female''s opportunity to obtain increased somatic benefits by mating with a particular male is limited, we investigated whether females obtain genetic benefits for their offspring via mate choice. Controlled breeding experiments conducted under favourable food and temperature conditions showed that developmental characters are heritable, that sire attractiveness and offspring survivorship are unrelated, but that females mating with attractive signallers produce offspring who mature faster than the offspring of females mating with non-attractive signallers. However, under some unfavourable food or temperature conditions, it is the offspring of females mating with non-attractive males who mature faster; these offspring are heavier as well. Thus, the relationship between male attractiveness and offspring development is not environmentally robust, and support for a good genes model of mate choice in A. grisella is dependent on conditions. These findings suggest genotype–environment interactions and emphasize the necessity of testing sexual selection models under a range of natural environments. 相似文献
103.
The ontogenetic and seasonal development of wax composition and cuticular transpiration of sun and shade leaves of ivy (Hedera helix L.) was analysed by investigating leaves varying in age between 4 and 202 d. It was discovered that the total amount of solvent-extractable
wax was composed of two distinct fractions, separable by column chromatography: (i) a less polar or apolar monomeric wax fraction
consisting of the typical linear, long-chain aliphatics usually described as cuticular wax components and (ii) a polar, oligomeric
wax fraction consisting of primary alcohols and acids mostly esterified to C12-, C14- and C16-ω-hydroxyfatty acids. The apolar wax fraction, which could be analysed directly by gas chromatography coupled with mass spectrometry
(GC-MS), exhibited pronounced seasonal changes in composition. Wax amounts in the apolar fraction reached a maximum after
about 30 d and gradually decreased again during the remaining period of the season investigated. In contrast, the polar wax
fraction, which was analysable by GC-MS only after transesterification, rapidly increased early in the season, reaching a
plateau after 40 d, and then remained constant during the rest of the season. Thus, total amounts of solvent-extractable cuticular
waxes, which can be determined gravimetrically, will only be detected by GC-MS after fractionation and transesterification,
a methodological approach rarely applied in the past in cuticular wax analysis. Additionally, investigation of the cutin polymer
matrix after depolymerisation through transesterification, revealed that only those primary alcohols and acids forming an
essential part of the apolar and the polar wax fractions were esterified during the investigated season and incorporated in
increasing amounts into the cutin polymer matrix (matrix-bound wax fraction). Thus, it can be concluded that a complete analysis
of cuticular wax of ivy and its seasonal development can only be achieved if all the relevant fractions (i) the less polar
or apolar, (ii) the polar and (iii) the wax fraction bound to the cutin polymer matrix are investigated. Cuticular transpiration
rapidly decreased within the first 30 d and essentially remained constant during the rest of the season. Thus, changes in
cuticular water permeability were closely correlated with the most prominent changes in wax amounts and composition occurring
during the first 30 d of ontogenetic leaf development. However, during the remainder of the year, up to 202 d, cuticular transport
properties remained constant, although significant quantitative and qualitative changes in cuticular wax composition continued
to occur. Thus, our study clearly demonstrated that there will be no simple relationship between chemical composition of cuticular
waxes and transport properties of isolated ivy leaf cuticles.
Received: 2 March 1998 / Accepted: 26 June 1998 相似文献
104.
The temperature-induced volume expansion of enzymatically isolated cuticular membranes of twelve plant species was measured. All cuticular membranes exhibited distinct second-order phase transitions in the temperature range of about 40 to 50° C. Increases in the volumes of fruit cuticles (Lycopersicon, Cucumis, Capsicum, Solanum and Malus) were fully reversible, while leaf cuticular membranes (Ficus, Hedera, Nerium, Olea, Pyrus, Picea and Citrus) underwent irreversible structural changes. Below the phase-transition temperature, volumetric expansion coefficients ranged from 0.39·10–6 m3·kg–1·K–1 to 0.62·10–6 m3·kg–1·K–1, and above from 0.60·106 m3·kg–1·K\-1 to 1.41· 10–6 m3·kg–1·K–1. Densities of cuticles at 25° C ranged from 1020 kg·m–3 to 1370 kg·m–3. Expansion coefficients and phase transitions were characteristic properties of the polymer matrix as a composite material, rather than of cutin alone. It is argued that the sudden increase of water permeability above the transition temperature, is caused by an increase of disorder at the interface between the polymer matrix and the soluble cuticular lipids. Possible ecological and physiological consequences of these results for living plants are discussed.Abbreviations CM
Cuticular membrane
- CU
cutin
- MX
polymer matrix
- SCL
soluble cuticular lipids (waxes)
The authors greatfully acknowledge stimulating discussions with Drs. H. Gruler (Exp. Physik 3, Universität Ulm, FRG) and M. Riederer (Institut für Botanik und Mikrobiologie, Technische Universität München, München, FRG) and financial support by the Deutsche Forschungsgemeinschaft. 相似文献
105.
Pinarosa Avato 《Planta》1984,162(6):487-494
Experimental evidence for a membranebound microsomal ester synthetase from Bonus barley primary leaves is reported. The results are consistent with at least two mechanisms for the synthesis of barley wax esters: an acyl-CoA-fattyalcohol-transacylase-type reaction and an apparent direct esterification of alcohols with fatty acids. Biosynthesis of wax esters was not specific with regard to the chain length of the tested alcohols. The microsomal preparation readily catalyzed the esterification of C16-, C18-, C22- or C24-labelled alcohols with fatty acids of endogenous origin. Exogenous long-chain alcohols were exclusively incorporated into the alkyl moieties of the esters. Addition of ATP, CoA and-or free fatty acids was not effective in stimulating or depressing the esterifying activity of the microsomal fraction. Partial solubilization of the ester synthetase was obtained using phosphate-buffered saline.Abbreviations P
pellet
- PBS
phosphate-buffered saline
- S
supernatant
- SDS
sodium dodecyl sulphate 相似文献
106.
107.
Mohammad Asadul Islam Hao Du Jing Ning Haiyan Ye Lizhong Xiong 《Plant molecular biology》2009,70(4):443-456
The outermost surfaces of plants are covered with an epicuticular wax layer that provides a primary waterproof barrier and
protection against different environmental stresses. Glossy 1 (GL1) is one of the reported genes controlling wax synthesis. This study analyzed GL1-homologous genes in Oryza sativa and characterized the key members of this family involved in wax synthesis and stress resistance. Sequence analysis revealed
11 homologous genes of GL1 in rice, designated OsGL1-1 to OsGL1-11. OsGL1-1, -2 and -3 are closely related to GL1. OsGL1-4, -5, -6, and -7 are closely related to Arabidopsis CER1 that is involved in cuticular wax biosynthesis. OsGL1-8, -9, -10 and -11 are closely related to SUR2 encoding a putative sterol desaturase also involved in epicuticular wax biosynthesis. These genes showed variable expression
levels in different tissues and organs of rice, and most of them were induced by abiotic stresses. Compared to the wild type,
the OsGL1-2-over-expression rice exhibited more wax crystallization and a thicker epicuticular layer; while the mutant of this gene showed
less wax crystallization and a thinner cuticular layer. Chlorophyll leaching experiment suggested that the cuticular permeability
was decreased and increased in the over-expression lines and the mutant, respectively. Quantification analysis of wax composition
by GC–MS revealed a significant reduction of total cuticular wax in the mutant and increase of total cuticular wax in the
over-expression plants. Compared to the over-expression and wild type plants, the osgl1-2 mutant was more sensitive to drought stress at reproductive stage, suggesting an important role of this gene in drought resistance.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
108.
Toshihide Sato Kazuhisa Nishishita Yukio Okada Kazuo Toda 《Cellular and molecular neurobiology》2009,29(4):503-512
A gap junction blocker, 18β-glycyrrhetinic acid (β-GA), increased the membrane resistance of Ia, Ib and II/III cells of frog
taste disk by 50, 160, and 300 MΩ, respectively, by blocking the gap junction channels and hemichannels. The amplitudes of
gustatory depolarizing potentials in the disk cells for 4 basic taste stimuli were reduced to 40–60% after intravenous injection
of β-GA at 1.0 mg/kg. β-GA of 1.0 mg/kg did not affect the resting potentials and the reversal potentials for tastant-induced
depolarizing potentials in any taste disk cells. The percentage of cells responding to each of 4 basic taste stimuli and varying
numbers of 4 taste qualities did not differ between control and β-GA-treated taste disk cells. This implies that gustatory
depolarizing response profiles for 4 basic taste stimuli were very similar in control and β-GA-treated taste disk cells. It
is concluded that β-GA at 1.0 mg/kg reduced the amplitude of gustatory depolarizing potentials in taste disk cells by strongly
blocking depolarizing currents flowing through the gap junction channels and hemichannels, but probably weakly affected the
gustatory transduction mechanisms for 4 taste stimuli. 相似文献
109.
Among sarcomeric muscles the cardiac muscle cells are unique by, inter alia, a systemic and extended cell-cell contact structure, the intercalated disk (ID), comprising frequent and closely spaced arrays of plaque-coated cell-cell adhering junctions (AJs). As some of these junctions may look somewhat like desmosomes and others like fasciae adhaerentes, the dogma has emerged in the literature that IDs contain - like epithelial cells - both kinds of AJs formed by - for the most - mutually exclusive molecular ensembles. This, however, is not the case. In comprehensive immunoelectron microscopic studies of mammalian (human, bovine, rat, mouse) and non-mammalian (chicken, amphibia, fishes) heart muscle tissues, we have localized major constituents of the desmosomal plaques of polar epithelia, desmoplakin, plakophilin-2 and plakoglobin, as well as the desmosomal cadherins, desmoglein Dsg2 and desmocollin Dsc2, in both kinds of ID AJs, independent of the specific morphological appearance. The desmosomal molecules are not restricted to the desmosome-like-looking junctions but can also be detected in junctions appearing similar to the zonula or fascia adhaerens structures. These AJs of cardiac ID are therefore subsumed under the collective term area composita. We discuss our results with respect to the importance of ID junction molecules for the formation, maintenance and function of the heart, particularly in relation to recent findings that deletions of - or mutations in - genes encoding such proteins can cause severe, sometimes lethal damages. 相似文献
110.
目的比较液基稀释法和纸片扩散法对临床常见皮肤癣菌的体外药物敏感性。方法应用Rosco纸片扩散法和微量液基法(参考美国国家实验室标准委员会NCCLS推荐的M38-P方案修改方案)测定临床分离的40株皮肤癣菌(包括红色毛癣菌、须癣毛癣菌、犬小孢子菌及絮状表皮癣菌)对两性霉素B、伊曲康唑、氟康唑和特比萘芬的体外药物敏感性。结果应用Rosco纸片扩散法,大部分菌株在7—9d时可读到清晰的结果。Rosco纸片扩散法和微量液基法结果中,特比萘芬、伊曲康唑和两性霉素B一致性较好,氟康唑较差。结论Rosco纸片扩散法操作简单,可选择用于皮肤癣菌对某些抗真菌药的药敏试验。 相似文献