首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
实验通过改变酶反应中的pH值,分析了星突江鲽蛋白酶、淀粉酶和脂肪酶的活性。结果表明,胃、肠和肝胰腺蛋白酶活性的最适pH值分别为3.8、8.2和7.8,各消化部位的最高点蛋白酶活性从高到低为:胃>肝胰腺>肠。胃、肠和肝胰腺淀粉酶活性的最适pH值分别为6.6、7.4和7.0,各消化部位的最高点淀粉酶活性从高到低为:肠>肝胰腺>胃。胃、肠和肝胰腺脂肪酶活性的最适pH值分别为7.4、7.8和7.8。各消化部位的最高点脂肪酶活性从高到低为:肝胰腺>肠>胃。  相似文献   

2.
Aegyptianellosis, eperythrozoonosis, grahamellosis and haemobartonellosis are diseases caused by procaryotic microorganisms which parasitize the erythrocytes of a variety of animals. Differentiation between Eperythrozoon and Haemobartonella is difficult. The parasites are similar in the living state, being small cocci or rods. In stained preparations Eperythrozoon may appear to be annular. The major criterion for differentiation is the relation of the parasite to the erythrocyte. Haemobartonellae are tightly attached to the erythrocyte and are rarely seen free in the plasma. Eperythrozoa are loosely attached to the erthrocyte, can be readily disloded and are often seen free in the plasma. Aegyptianella which occurs intracellularly in an inclusion is easily differentiated from the others while Grahamella, which is rod shaped, is always intracellular and is not in an inclusion but is scattered throughout the erythrocyte's cytoplasm. These organisms are not generally pathogenic. A slight parasitemia, mild anemia and slight fever may follow infection in the intact animal. Most infected animals remain nonclinical carriers. Splenectomy of a carrier animal or infection of a splenectomized animal will produce high parasitemia; even then, the physiological disturbance is mild. The only exceptions to the general rule that infection with these organisms produces a mild disease in intact animals are infections with Aegyptianella pullorum, Eperythrozoon suis and Haemobartonella felis. Aegyptianella pullorum produces aegyptianellosis of fowl, a disease characterized by anemia, E. suis produces “icteroanemia of swine” and H. felis produces “filine infectious anemia”.  相似文献   

3.
A full history of four nominal species of southern African dendrochirotid holothurians, namely Cucumaria jägeri Lampert, Semperia (= Cucumaria) sykion Lamped, C. insolens Theél and C. sinorbis Cherbonnier, is given and the confusion in their taxonomic status discussed. Morphological differences and habitat selection indicate that the latter three are valid sister species. C. jägeri is relegated to the synonymy of C. sykion, a well-established name which it threatens. Since none of the three species is referable to the genus in which it is currently classified, a new genus Pseudocnella is erected to accommodate them. It is suggested that the Mediterranean Ocnus syracusanus (Grube) be also classified in the new genus. A key to the three southern African species is given, their synonymy detailed, additional notes provided, and the geographic distributions mapped. Although P. sykion and P. sinorbis have an identical geographical range it is demonstrated that the two species are ecologically isolated and thus prevented from any interspecific competition. P. insolens is sympatric with P. sinorbis over a wide area, often occupying the same habitat in a single locality. However, morphological and other evidence points to subtle niche differences between them. A provisional cladogram is proposed to show the possible relationships of the four species included in the new genus.  相似文献   

4.
Cyclosporine is an immunomodulatory drug used to treat an increasing spectrum of diseases in dogs. Cyclosporine is a calcineurin inhibitor, ultimately exerting its inhibitory effects on T‐lymphocytes by decreasing production of cytokines, such as interleukin‐2. Although, in the United States, oral cyclosporine is approved in dogs only for treatment of atopic dermatitis, there are many other indications for its use. Cyclosporine is available in 2 oral formulations: the original oil‐based formulation and the more commonly used ultramicronized emulsion that facilitates oral absorption. Ultramicronized cyclosporine is available as an approved animal product, and human proprietary and generic preparations are also available. Bioavailability of the different formulations in dogs is likely to vary among the preparations. Cyclosporine is associated with a large number of drug interactions that can also influence blood cyclosporine concentrations. Therapeutic drug monitoring (TDM) can be used to assist in attaining consistent plasma cyclosporine concentrations despite the effects of varying bioavailability and drug interactions. TDM can facilitate therapeutic success by guiding dose adjustments on an individualized basis, and is recommended in cases that do not respond to initial oral dosing, or during treatment of severe, life‐threatening diseases for which a trial‐and‐error approach to dose adjustment is too risky. Pharmacodynamic assays that evaluate individual patient immune responses to cyclosporine can be used to augment information provided by TDM.  相似文献   

5.
No consensus has yet been reached concerning Old World treefrog systematics. Competing hypotheses are based on differing and sometimes conflicting methodologies. I use cladistic methodology to reanalyse the data from the two most important recent studies. Two monophyletic groups result; Rhacophoridae and Hyperoliidae. Seven subfamilies are recognized; six are monophyletic (Hyperoliidae: Hyperoliinae, Kassininae, Leptopelinae, Tachycneminae; Rhacophoridae: Buergeriinae, Mantellinae), while the Rhacophorinae are polyphyletic. The taxonomic changes from the standard Amphibian Species of the World (Frost 1985) proposed are: Acanthixalus is removed from the Leptopelinae and placed in the Hyperoliinae. Tachycnemis is removed from the Hyperoliinae and placed in its own subfamily, Tachycneminae. Opisthothylax is removed from the Hyperoliinae and placed in the Kassininae. Afrixalus and Kassinula are removed from the Kassininae and placed in the Hyperoliinae. Aglyptodactylus is removed from the Rhacophorinae and placed in the Mantellinae. Buergeria is placed in the subfamily Buergeriinae. The Mantellinae, previously in the Ranidae, is demonstrated to be a subfamily within the Rhacophoridae. The biogeography of the group is interpreted in terms of a simplified area cladogram. The most parsimonius vicariance hypothesis proposes that the stock leading to the Hyperoliidae and Rhacophoridae existed before Pangaea broke up. The sequence of fragmentation events leading to the present-day distribution started with the Seychelles, then Asia split from Africa+Madagascar, and finally Africa and Madagascar separated.  相似文献   

6.
Abstract

A survey of 3–8-year-old peamouths Mylocheilus caurinus collected from the lower Fraser River, British Columbia, revealed 100%, infection by a myxosporean identified as Myxobolus cyprini based on spore morphology, site of infection, and associated pathological changes. Myxobolus cyprini is a common myxosporean parasite of several species of cyprinid fishes (family Cyprinidae) in Europe, the former USSR, and China, but this is the first report of this myxosporean in the Western Hemisphere. The source of the infection in peamouths—whether the parasite is endemic to North America or has been imported with exotic cyprinids from Europe or Asia—is unknown. It is also possible that the myxosporean from peamouths is very closely related to, but a distinct species from, M. cyprini of Eurasia. As reported from European cyprinid fishes, the myxosporean in peamouths developed in the skeletal muscle, and disseminated spores were found associated with chronic inflammation in the visceral organs.  相似文献   

7.
After administration of sulphanilamide to goats and cows, sulphanilamide is excreted into milk. The concentrations of sulphanilamide in ultrafiltrate of milk (M. Ultr.) and blood plasma (P. Ultr.) are equal and the ratio M. Ultr./P. Ultr. is 1.0. The pKa of sulphanilamide is 10.4 and thus, sulphanilamide is un-ionized in both milk and blood plasma. Therefore, sulphanilamide is excreted into milk in accordance to the theory of passive diffusion of the non-protein-bound and un-ionized fraction in blood plasma (Rasmussen 1958, 1966; Miller et al. 1967). A similar ratio was expected for acetylated sulphanilamide with a pKa of 10.3. However, the concentration of the acetylated derivative is always found higher in milk than in plasma. This might be due to formation of acetylated sulphanilamide in the mammary tissue, as demonstrated by Rasmussen & Linzell (1967) or active excretion of the compound just as in the case of N4-acetylated p-aminohip-puric acid (Rasmussen 1969).  相似文献   

8.
The present report describes Syphacia (Syphacia) maxomyos sp. n. (Nematoda: Oxyuridae) from two species of spiny rats, Maxomys musschenbroekii from Sulawesi and M. whiteheadi from Sumatra. It is characterized by a cephalic plate extending laterally with dorsoventral constriction and stumpy eggs with an operculum rim reaching pole. It is readily distinguishable by the former feature from all of hitherto known representatives of this genus in Indonesia, but it resembles parasites in Murini and Hydromyni rodents in continental Asia and Sahul. This is the first Syphacia species distributed in both the Sunda Shelf and Sulawesi with the exception of Syphacia muris, a cosmopolitan pinworm found in rodents of the of genus Rattus. It is surmised that S. maxomyos is specific to Maxomys and that it was introduced to Sulawesi by dispersal of some Maxomys from the Sunda Shelf.  相似文献   

9.
Bovine sarcocystosis is caused by Sarcocystis cruzi and is known to cause considerable morbidity and mortality in cattle. This species is distributed worldwide in cattle and is the most prevalent of the Sarcocystis species infecting cattle. There is high infection rate of sarcocyst in cattle in Iran, but to our knowledge, there is no study about identification of Sarcocystis species. This work aimed to survey prevalence of S. cruzi cyst in slaughtered cattle of Isfahan, Iran. In this study, esophageal and diaphragmatic muscles of 100 cattle were collected from Fesaran abattoir of Isfahan and examined for the presence of Sarcocystis spp. cysts macroscopically and microscopically. No macroscopic sarcocysts were found in any of the samples. In light microscopy, 89 out of 100 cattle (89%) had thin-walled cysts of S. cruzi, while 21 out of them (21%) had thick-walled sarcocysts. In addition to light microscopy, ultrastructural features of the thin-walled cyst confirmed the presence of S. cruzi.  相似文献   

10.
Four anuran taxa inhabit the central Namib: Xenopus laevis, Tomopterna delalandei cryptotis, Phrynomerus annectens and Bufo vertebrate hoeschi. Xenopus is confined to permanent pools in the Kuiseb river canyon. Tomopterna extends further into the Namib, but is restricted to the Kuiseb river bed. The Kuiseb is normally dry, receiving water only briefly (as floods) during the rainy season. These floods are responsible for moving adults and larvae. Phrynomerus and Bufo occur on granite inselbergs. The inselbergs provide shelter mainly in the form of cracks under granite exfoliations. Large runoff surfaces collect the low rainfall (25 mm per year) in depressions in which the frogs breed. Phrynomerus is only active at night; males are aggressive towards one another; oviposition takes place in deep pools and development takes at least eight weeks. Bufo is active during the heat of the day; oviposition takes place in warm shallow pools; development takes about three weeks.  相似文献   

11.
Summary

Transmission of F.hepatica under natural conditions was analysed in a three year programme. The variables used were the indirect haemagglutination (IHA) technique, worm establishment in tracer lambs and the population dynamics, infection rate and shedding pattern of Lymnaea truncatula.

It is concluded that fluke eggs, infected snails and metacercariae on herbage can survive the winter in the Netherlands. Metacercarial availability was positively correlated to the amount of rainfall in the grazing period. The role of developed eggs that survive the winter is important, because this results in earlier infections in the herd.

The use of the serological diagnosis method IHA is important to detect F. hepatica infection in an early stage. Use of cellophane paper on floats is a useful method for determining the shedding pattern of cercariae from L. truncatula. It is concluded that collection of metacercariae on cellophane floats, inventarization of L. truncatula and its infection level are useful tools for the prediction of liverfluke infections.  相似文献   

12.
Equine piroplasmosis (EP) is a hemoprotozoan disease cased by Babesia caballi and B.equi. It is a tick-borne disease principally characterized by fever, anemia, and icterus. Clinically inapparent babesia carrier horses are important in the dissemination of the disease. Clinical episodes occur under two conditions:
1. When susceptible horse stock is moved into endemic EP areas; and
2. When inapparent babesia carriers are moved into non-endemic areas, then in the presence of certain ticks, babesiasis is spread to the susceptible horse population.
Ticks are the principal vectors of equine piroplasmosis, additionally contaminated hypodermic needles have shown to spread B. equi among horses. In endemic EP areas, it has been shown that babesiasis can cause unthriftyness in foals.Control of babesiasis is principally directed at tick control. Various tickacidal sprays or dips can be used to break the life cycle of ticks.Chemotherapy, using certain aromatic diamidines, is an adjunct to tick control and also facilitates the international relocation of horses and other equidae. Objectives of chemotherapy are divided as follows: 1. In EP endemic areas, the therapeutic aim is to subdue the babesia parasites and leave the host horse in a state of premunition; and 2. In non-endemic areas, complete clearance of babesia organisms from the animal is the objective. Several aromatic diamadine pharmaceuticals are available to veterinarians.During recent years, horses and other equidae have become important in international commerce. Such commerce has focused attention on the international spread of certain infectious and communicable animal disease; among these is equine piroplasmosis (EP).Piroplasmosis is an infectious hemoprotozoan disease characterized by fever, anemia, icterus, and other signs arising from hemolysis caused by Babesia caballi or Babesia equi. The disease has been reported in horses, mules, donkeys, and zebras.8  相似文献   

13.
In most mammals, glucokinase (GK) acts as a hepatic “glucose sensor” that permits hepatic metabolism to respond appropriately to changes in plasma glucose concentrations. GK activity is potently regulated by the glucokinase regulatory protein (GKRP), which is encoded by the GCKR gene. GKRP binds GK in the nucleus and inhibits its activity. GK becomes active when it is released from GKRP and translocates to the cytosol. Low glucokinase (GK) activity is reported to be a principal feature of feline hepatic carbohydrate metabolism but the molecular pathways that regulate GK activity are not known. This study examined the hypothesis that species-specific differences in GKRP expression parallel the low GK activity observed in feline liver. Hepatic GKRP expression was examined using RT-PCR, immunoblot, and confocal immunomicroscopy. The results show that the GCKR gene is present in the feline genome but GCKR mRNA and the GKRP protein were absent in feline liver. The lack of GKRP expression in feline liver indicates that the low GK activity cannot be the result of GKRP-mediated inhibition of the GK enzyme. However, the absence of the permissive effects of GCKR expression on GK expression and activity may contribute to reduced GK enzyme activity in feline liver. The study results show that the cat is a natural model for GCKR knockout and may be useful to study regulation of GCKR expression and its role in hepatic glucose-sensing and carbohydrate metabolism.  相似文献   

14.
SUMMARY The distribution of the three known species of Onchocerca in Australian cattle is described. O. gutturosa was found in the ligamentum nuchae, on the scapular cartilage and in the hip, stifle and shoulder regions. Nodules of O. gibsoni were found in the brisket***, stifle and hip regions, while O. lienalis occurred along the gastrosplenic ligament and above the xiphisternum. O. gutturosa is potentially the most important species to the meat industry since it is widely distributed in the carcase and is easily missed during inspection. Trimming procedures which could be used to ensure removal of known sites of infection are outlined.  相似文献   

15.
The anatomy of the sternum in birds varies according to their habitats and type of locomotion. In particular, the carina sterni manifest different shape variations. In this study, the shape of the carina sterni was investigated by means of geometric morphometrics. Birds of different types of locomotion were used in the study: flying, swimming, and terrestrial. Ducks and chickens show a wider variety of shapes. Pigeons are the species with the least differences. The margo cranialis carinae in a turkey is the flattest compared to other species. In chickens, the apex carinae is more caudally than the base of the carina sterni. The margo cranialis of the carina sterni in ducks is concave. The differences in centroid size and shape differences between species collectively are statistically significant (p < 0.0001). The most distinct shape contrast is between the duck and turkey (p: 0.0003). Form differences between the ducks and geese as well as between the chicken and turkey are statistically insignificant. There is less variation in the shape of the carina sterni among avian species representing the same type of locomotion. Although there are many comparative morphological and morphometric studies of birds, shape analysis studies revealing the interspecific differences and similarities of the sternum are very limited. Morphology of the carina sterni can be useful in taxonomic investigations.  相似文献   

16.
A new genus Roweia in the holothurian family Cucumariidae is erected to accommodate two southern African dendrochi-rotids, Cucumaria frauenfeldi Ludwig and C. stephensoni John which have previously always been classified in Cucumaria (si). Some intraspecific variations in R. frauenfeldi are discussed and, on this basis, the species is rediagnosed and two subspecies recognized. The species and subspecies of the new genus are keyed, their synonymy is considered and distributions mapped. New information in regard to R. stephensoni is also included.  相似文献   

17.
Feed conversion ratio (FCR), which defines the feed requirement in kg per kg body weight gain, is an important measure for judging the economic and breeding performance of a fattening pig. It is dependent on many different factors which include (1) the level of feeding, which affects the maintenance requirements, (2) the energy value of the ration and (3) the energy concentration of the body weight gains (cg). The influence of these factors on FCR and, in general, on growth performance, is discussed using results from growth and balance experiments. Some inter-relationships between the factors are described and integrated into a model which predicts FCR.An increase in the level of feeding can reduce FCR. Experimental results indicate that the ad libitum fed pig has a lower maintenance requirement than the restrictively fed animal due to a reduction in its physical activity. As the level of feeding increases, there is usually a rise in cg and an accompanying decline in FCR. However, FCR is only a useful indicator for judging the energetic efficiency of growth when cg is known. A small FCR is only found when body weight gains are high and cg low.  相似文献   

18.
Lafora disease is a fatal genetic disorder characterised by neurotoxic deposits of malformed insoluble glycogen. In humans it is caused by mutation in the EPM2A or NHLRC1 genes. There is a known mutation in miniature wirehaired dachshunds which has not been documented in other dog breeds, including beagles, in which the disease is relatively commonly reported. This case report describes the causative defect in two affected beagles, namely the same massive expansion as in miniature wirehaired dachshunds of a 12‐nucleotide repeat sequence that is unique to the canine NHLRC1 gene. This is the first mutation described in beagles with Lafora disease, and so far the only Lafora disease genetic variant in dogs.  相似文献   

19.
The Japanese quail has several advantages as a low‐fat meat bird with high immunity against diseases. Cathelicidins (CATHs) are antimicrobial peptides that play an important role in innate immunity. The aim of this study was to characterize the CATH cluster in the Japanese quail (Coturnix japonica). The Japanese quail CATH (CjCATH) cluster, contains four CATH genes, as in the chicken. The coding sequences of CjCATHs exhibited >85.3% identity to chicken CATHs. The predicted amino acid sequences of the four CjCATH genes contained the cathelin‐like domain characteristic of CATH proteins. Polymorphisms were detected in the open reading frames (ORFs) of all CjCATH sequences. Two amino acid substitutions were observed in the antimicrobial region of the mature peptide of CjCATH2, and predicted to influence peptide function. CjCATH1 is expressed in lung, heart, bone marrow and bursa of Fabricius (BF). CjCATH2 is expressed in bone marrow. CjCATH3 is expressed in lung, heart, bone marrow, BF, tongue and duodenum. CjCATHB1 is expressed in bone marrow and BF. This study is the first to characterize CATH genes in the Japanese quail, and identifies novel antimicrobial peptide sequences belonging to the cathelicidin family, which may play a role in immunity in this species.  相似文献   

20.
The enzymes 3α- and 3β-hydroxysteroid dehydrogenase (3α- and 3β-HSD) play a pivotal role in synthesis of various steroid hormones including oestradiol and testosterone. The structure of the mycotoxin zearalenone resembles many characteristics of steroids and binds to oestrogen receptors as an agonist. Consequently, it is suggested that zearalenone is also a substrate for 3α-HSD and 3β-HSD. 3α-HSD and 3β-HSD isoforms are expressed in the liver and kidney but also in many steroidogenic tissues. It was the aim of the present study to demonstrate the presence of these enzymes in granulosa cells, which were obtained from bovine and porcine ovaries, and to investigate whether zearalenone is a substrate for these enzymes. The results show a species-specific expression pattern in the granulosa cells of both species. Moreover, it was demonstrated that zearalenone when added to the culture medium, is converted into α-zearalenol and β-zearalenol. Corresponding to the apparent expression profile, in porcine granulosa cells predominantly α-zearalenol was formed, whereas bovine granulosa cells preferentially converted zearalenone into β-zearalenol. This is the first report demonstrating the extrahepatic biotransformation of zearalenone in target tissues.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号