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41.
42.
Leon Grubisic Gorana Jelic Mrcelic Neda Skakelja Ivan Katavic Vijeko Ticina & Merica Sliskovic 《Aquaculture Research》2007,38(9):991-1001
A 4‐year study (May 1997–December 2000) of the reproductive biology of pink dentex Dentex gibbosus (Rafinesque) from the Adriatic Sea revealed that this species is a rudimentary hermaphrodite. The smallest mature males and females captured were 38.70 cm in total length (TL) and 39.80 cm in total length (TL) respectively. The von Bertalanffy growth parameters estimated for the entire population were: L∞=107.24, K=0.12 and t0=−0.90. Fifty per cent of the population were sexually mature at 41.50 cm TL, while 100% of the specimens were sexually mature at 57.00 cm TL. Both monthly gonadosomatic index and macroscopically determined gonad stages strongly indicate that the pink dentex from the Adriatic Sea spawn partially in August, September and October. The mean value of absolute fecundity (F) was 1672 × 106 eggs. The results of great fertility of the pink dentex, partial spawning and relatively late sexual maturation suggest that the pink dentex has a high potential for commercial culture. 相似文献
43.
44.
A sublethal dose (0.1 pmol per honeybee, i.e., approx. 0.9 pmol/g body wt) of the synthetic pyrethroid, deltamethrin, was injected intrathoracically into the hemocoel of emerging bees and the biochemical effects were determined over a period of 3 hr. The variations in hemolymph concentrations of trehalose, glucose, phospholipid, steroid, and diacylglycerol were limited, but large variations were observed for other lipids. Mono- and triacylglycerols increased dramatically 1.5 hr after injections; then a peak of free fatty acid appeared at the same time (3 hr) as the monoacylglycerols reached their maximum and the triacylglycerols started to decrease. Atypical forms of triacylglycerols accumulated from 1.5 hr to a maximum level 2 hr after injection. Then, after 3 hr, the concentrations of regular fatty acids, monoacylglycerols, and atypical triacylglycerols returned to normal while longer-chain fatty acids and different forms of ceride simultaneously appeared. The gut alkaline phosphatase parameters (VM, K, and Hill coefficient) also showed large variations 1.5 and 2 hr after injection, indicating an initial inhibition phase followed by superimposed induction and inhibition mechanisms. These data are discussed according to the hemolymph-lipid transport scheme from the biosynthetic to the utilization sites. Hormone release associated to mitochondrial alteration could be responsible for the observed effects. 相似文献
45.
46.
Ivermectin is one of the most commonly used drugs in pharmacotherapy of parasitic diseases in domestic and wild animals caused
by parasitic nematodes and arthropods. However, ivermectin and other avermectins very often produce side-effects in hosts.
The most dominant clinical symptom of ivermectin toxicity in domestic and wild animals is CNS depression. In nematodes, the
target site of ivermectin’s action is glutamate-gated chloride-channel receptor and GABA receptor. The depressive effect of
ivermectin in mammals might include more than one mechanism; therefore, the anticonvulsive effect of ivermectin against convulsions
caused by lidocaine and strychnine was evaluated. Ivermectin antagonized lidocaine- and strychnine-induced convulsions in
rats, although these have different mechanisms. In the present study, the anticonvulsive ED50 of ivermectin for lidocaine-induced convulsions was 2.44 mg/kg (95% CL 1.67 to 3.57 mg/kg), whereas for convulsions induced
by strychnine it was higher at 4.25 mg/kg (95% CL 2.32 to 3.78 mg/kg). At the same time, both anticonvulsive doses are significantly
lower then the observed LD50 of ivermectin (18.20 mg/kg). Furthermore, flumazenil (0.1 and 0.2 mg/kg), an antagonist of benzodiazepine receptors, antagonizes
just one part of these anticonvulsive effects of ivermectin. Our results show the significant anticonvulsive properties of
ivermectin and support the findings that ivermectin in the CNS of mammals produces multiple inhibitory effects, probably through
participation in the function of GABA-sensitive and GABA-insensitive chloride channels. 相似文献
47.
Cultivars of common bean (Phaseolus vulgaris L.) capable of yielding well at low levels of native or added phosphorus (P)
are highly desirable in many tropical production systems. The objective of the present study was to identify geographical
regions which might be sources of such genotypes. A total of 364 landraces, cultivars and wild genotypes, drawn from a broad
geographic range, were divided on the basis of growth habit into four field trials, each comprising two levels of P, stressed
and unstressed, on an infertile Andosol in Popayan, Colombia. The regression relationship between grain yield per plant in
the presence and in the absence of stress was determined, and each genotype's deviation from this relationship was used as
a measure of P-efficiency. There was highly significant variation in efficiency among genotypes in all growth habits, and
in climbing beans there were consistent regional differences, superior genotypes being identified with greater frequency among
those from Bolivia, West Mexico and South Mexico-West Guatemala. The latter region was promising for prostrate bush genotypes
also. Wild beans in general performed relatively poorly; it appears that P-efficiency traits in P. vulgaris have been acquired
during or after domestication. These results confirm that genetic differences in P-efficiency exist among common bean genotypes
and suggest that these are related to geographic origin. Furthermore, the use of a representative sample of germplasm can
help to identify segments of the gene bank that are especially promising as sources of desirable traits.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
48.
Summary The occurrence of chromosomal interchanges was studied in F1 hyrids in two diallel schemes, including nine accessions of Triticum aestivum subsp. spelta, originating from Iran, Europe and North Africa, and the common wheat variety Chinese Spring as a reference. Seven accessions of subsp. spelta differed in one translocation from Chinese Spring. The European accession Grey differed in one or perhaps two interchanges from the reference variety, and Iran 417a showed a difference of three interchanges with Chinese Spring. In total six or perhaps seven interchanges were observed. Thus the number of translocation events in subsp. spelta appeared to be low. One translocation was unique and occurred only in the accession from North Africa. Also one accession from Europe, the landrace Schwarzwald, possibly carried a unique translocation. In both diallels an interchange with a relatively low coefficient of multivalent realisation at first meiotic metaphase was observed in most accessions. The two extra translocations in Iran 417a are considered to be the result of more recent translocation events, whereas the possible second translocation in accession Grey showed such a low coefficient of multivalent realisation that its existence could be doubted. 相似文献
49.
Branimir Urlić Gvozden Dumičić Smiljana Goreta Ban Marija Romić 《Journal of plant nutrition》2016,39(3):389-398
Understanding the mechanisms of phosphorus (P)-use efficiency (PUE) may contribute to enhancing crop P nutrition because species growth variability at low-P is well known. The experiment was carried out to evaluate the response of kale genotypes to different P supply in randomized block design in three replications. Low-P supply led to a decrease in most parameters, whereas an increase was recorded in root growth parameters. Genotypes differed in shoot dry weight (DW), leaf area, root length and area, and shoot and root P content and concentration. Root traits significantly positively correlated with PUE. Genotypes Red Russian (RR) and IJK 17 were superior in terms of shoot DW production at low P supply, and had the highest uptake efficiency. Genotypes IJK 17 and 81 had the highest P utilization efficiency, while Vates blue curled (VBC) showed the lowest PUE. Genotypes had similar shoot P content and concentration at low P supply, but large PUE differences, implying the importance of P utilization efficiency. 相似文献
50.
The influence of mesoscale weather patterns on the chemical composition of daily precipitation samples is analysed. The data of pH, sulphur from sulphates and total nitrogen are analysed for two rural sites: Plitvice station in forested part of Central Croatia (1981 to 1990) and Puntijarka suburban station on the mountain near Zagreb, the capital of Croatia (1982–1991). The two prevailing weather types in precipitation days are selected and the comparison of chemical composition of precipitation is made for each of them. The frequency distributions of pH, sulphur and nitrogen show that concentration of major ions in precipitation apparently depends on the regional scale weather type. It is shown that the seasonal variation of deposition is related to the seasonal variation in precipitation amount. In both weather types Plitvice receives more pollution than Puntijarka that is closer to urban and industrial pollution sources. Both locations are under the prevailing influence of regional pollution sources. 相似文献