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1.
The osmoregulatory abilities of the grapsoid crabs Cyclograpsus punctata*, Sesarma catenata andSesarma eulimene were studied comparatively in an attempt to explain, at least in part, their distribution in estuaries. Both survival and haemorymph osmotic pressure were used as indices of hyperosmotic regulatory ability.

All three species were shown to be capable of regulating their haemorymph osmotic pressure against lowered external salinities. S. eulimene was found to be better able to control its haemorymph concentration in very low salinities than S. catenata, which would account for the former's occurrence in the upper reaches of estuaries. C.punctatus was shown to be capable of roaintaining its haemorymph osmotic pressure above that of the environmental medium in lowered salinities, but without the degree of constancy characteristic of the two Sesarma species. It does, however, show a marked ability to tolerate lowered internal osmotic pressure, an ability which appears to develop in response to partial dilution of the haemorymph. These adaptations, together with its semi-terrestrial habit as a shore crab, suffice to enable C. punctata* to penetrate an estuary to almost the same extent as S. catenata.  相似文献   
2.
中草药提取技术的概述   总被引:1,自引:0,他引:1  
简述了中草药的系列提取方法及其应用。其中对101-澄清剂提取法作了较详细的介绍,因为该法是目前应用最广、效果最好、简易可行、经济实用的可替代醇沉法的一种新型提取方法。  相似文献   
3.
East Coast fever, an acute lymphoproliferative disease of cattle, is caused by the apicomplexan parasite Theileria parva. Protective immunity is mediated by CD8(+) cytotoxic T lymphocytes directed against schizont-infected cells. The polymorphic immunodominant molecule, although an antibody-inducing surface molecule of the schizont, has been hypothesized to play a role in protective immunity. In order to evaluate the immunogenicity of PIM for inducing CTL, cattle were immunized with PIM in isolation from other T. parva antigens, forcing the presentation of PIM-derived epitopes on the MHC class I molecules. Although parasite-specific cytotoxicity was induced in both vaccinated animals, their immune response was clearly different. One animal generated MHC-restricted parasite-specific CTL against PIM while the other calf exhibited a strong PIM-specific proliferative response but non-MHC-restricted parasite-specific cytotoxicity. Only calf 1 survived a lethal sporozoite challenge. This DNA immunization technique with an antigen in isolation of CTL-immunodominant antigens might open possibilities for directing CTL responses against predefined antigens, such as strain cross-reacting CTL antigens.  相似文献   
4.
Genomic selection in tea plant (Camellia sinensis) breeding has the potential to accelerate efficiency of choosing parents with desirable traits at the seedling stage. The study evaluated different genome-enabled prediction models for black tea quality and drought tolerance traits in discovery and validation populations. The discovery population comprised of two segregating tea populations (TRFK St. 504 and TRFK St. 524) with 255 F1 progeny and 56 individual tea cultivars in validation population genotyped using 1,421 DArTseq markers. Twofold cross-validation was used for training the prediction models in the discovery population on eight different phenotypic traits. The best prediction models in the discovery population were consequently fitted to the validation population. Of all the four model-based prediction approaches, putative QTLs (Quantitative Trait Loci) + annotated proteins + KEGG (Kyoto Encyclopaedia of Genes and Genomes) pathway-based prediction approach showed more robustness. The findings have for the first time opened up a new avenue for future application of genomic selection in tea breeding.  相似文献   
5.
Objective To investigate wool organophosphorus concentrations resulting from a range of farm pesticide application methods.
Design Random sampling of wool for pesticide residues and on-farm interviews to determine associated treatments.
Procedure Tasmanian fleece wool lots were sampled at random and tested for organophosphorus residues. The grower was identified and the pesticide treatments applied to the sheep were ascertained by on-farm interview.
Results The residue concentrations showed a large variation that was not accounted for by differences in treatments by growers. Organophosphorus concentrations were proportional to the number of treatments applied, and inversely related to the time between pesticide application and the subsequent shearing, and were significantly influenced by the method of application. After allowing for the time of application, plunge dipping resulted in pesticide residue concentrations 2 to 2.5 times greater than shower dipping, using spray races or hand jetting, and the use of these methods caused larger residues than the use of jetting races.
Conclusions We recommend that plunge or shower dipping should not be used more than 7 weeks after shearing, nor at higher concentration than the standard dose rate used for lice control, whereas jetting may be satisfactory for up to 7 months after shearing, provided only one application is administered.  相似文献   
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The influence of trehalose on European mouflon spermatozoa cryopreservation during the non-breeding season was tested. Semen was frozen in two different extenders: (a) recommended Tris-based ram extender (CTR); (b) CTR extender supplemented with trehalose 0.147 mm (TRH). Sperm viability and acrosome integrity were assessed using propidium iodide and fluorescein isothiocynate labelled Pisum Sativum agglutinin. Trehalose significantly enhanced sperm viability after thawing compared with CTR extender (62.7% vs 51.8%; p < 0.05), whereas no differences were observed on acrosome integrity (42.9% vs 42.1%). Trehalose influence was also evidenced in the in vitro fertility test performed with sheep oocytes matured in vitro. Both fertilization rates (60.9% TRH vs 43.6% CTR; p < 0.05) and cleavage rates (58% TRH vs 39.8% CTR; p < 0.001) were higher for trehalose frozen semen compared with control extender frozen semen. A higher percentage of zygotes resulting from fertilization with trehalose cryopreserved semen presented the first cleavage earlier if compared with the group fertilized with control semen (48.7% vs 31.5%, respectively; p < 0.01). This result was confirmed by embryo kinetic development. Fertilization with trehalose cryopreserved semen leaded to an higher percentage of blastocysts (40.2% vs 27.8% CTR; p < 0.05), and enhanced in particular the number of blastocysts that developed on the day 6th of culture (28.6% vs 17% CTR; p < 0.05). Our data demonstrated that, during mouflon non-breeding season, trehalose extender enhances spermatozoa viability and its in vitro fertilizing capacity, allowing the production of an higher number of blastocysts.  相似文献   
10.
Abalone is currently considered South Africa's most successfully produced aquaculture export product, with a 76% share of the total value generated by the aquaculture sector. A major risk factor for this sector is slow growth rates experienced during farming. Abalone feeds are often supplemented with amino acids in an attempt to enhance abalone growth. This is a first investigation of the effect of added proline to standard abalone feed, on the metabolite profile of slow‐growing abalone. A targeted liquid chromatography tandem mass spectrometry metabolomics research approach was followed to recognise the metabolic response of abalone showing slower growth performance. The addition of proline to the standard abalone diet was found to serve as a substrate for amino acid catabolism in slower growing abalone, by means of proline breakdown to assist with energy production via the tricarboxylic acid cycle. Other amino acids and urea cycle intermediates, that is, arginine, asparagine, ornithine and creatine further support energy production via the action of protein catabolism in slow‐growing abalone. Additionally, the importance of understanding how abalone respond metabolically to modified feed highlights the use of metabolomics to answer abalone aquaculture farming questions.  相似文献   
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