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 15 毫秒
1.
We confirmed, with the electron microscope, that Trichinella larvae feed directly on the host tissue during their initial development. They suck, by means of a stylet acting as a piston, all components of the muscle cell which develops into a nurse cell, into their oral cavity. The stylet is controlled by a muscle retractor. At day 10 p.i., fragments of myofilaments and glycogen are present in the oesophagus of the larva of T. nativa, mitochondria occur in it at day 20 p.i. During the larval growth of T. pseudospiralis, remnants of a contractile material are present in the digestive system. The composition of the food ingested by the larva is in agreement with the development of changes in the muscle fibre. Initial changes in the fibre caused by the two Trichinella species are comparable, later changes are not. T. pseudospiralis influences the character of changes by its uninterrupted movement inside the fibre. From days 50-90 p.i. with T. pseudospiralis, a focally distributed sarcotubular system proliferates irregularly in different sites of the fibre. This is in contrast to a heavy proliferation of tubules inside a concentric membranous system around the larva of T. nativa becoming enclosed in a capsule. The larva which has ceased to feed on the host tissue at this time, feeds apparently on low-molecular substances of the membranous system transported from the surrounding vascular system which has increased in quantity in the endomysium. In the later course of the infection, the enzymatic activity of the AIP and the SDH increases in the vicinity of the larva of T. nativa, i.e., in the sarcoplasm inside the capsule.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

2.
The effects of vitamins A, B complex, E, and ADE on the eosinophilia, body weight, number of obtained larvae and distribution of larvae of Trichinella pseudospiralis were examined in mice. The increased eosinophilia started to appear in the majority of infected mice from day 7 p.i., the maximum being around day 21 p.i. The highest values of eosinophilia were observed in the mice after application of vitamin B complex. In spite of considerable individual differences, the greatest decrease in body weight occurred in mice receiving vitamins E and B complex. The greatest numbers of larvae were obtained from mice receiving vitamins E and B complex, which is proportional to the increase in eosinophilia. The numbers of muscle larvae in untreated mice and in those receiving vitamins ADE were approximately the same. The lowest numbers of larvae occurred in mice receiving vitamin A. In all mice groups the greatest numbers of larvae were localized in the left foreleg and diaphragm.  相似文献   

3.
Two new nematodes, Paraseuratoides ophisterni gen. et sp. n. (Seuratoidea: Quimperiidae) and Philometra ophisterni sp. n. (Dracunculoidea: Philometridae) are described based on specimens recovered from the intestine and mesentery, respectively, of the swamp-eel Ophisternon aenigmaticum Rosen et Greenwood (Synbranchiformes: Synbranchidae) from a canal of the Papaloapan River in Tlacotalpan, State of Veracruz, Mexico. The genus Paraseuratoides is mot similar to Paraseuratum Johnston et Mawson, 1940, differing from it mainly in the absence of a bulbous inflation on the anterior end of the oesophagus and in the structure of the mouth (presence of 6 spines in addition to 6 oesophageal teeth). Neoquimperia Wang, Zhao, Wang et Zhang, 1979 and Wuinema Yu et Wang, 1992 are synonymised with Ezonema Boyce, 1971 and Paragendria Baylis, 1939, respectively, and Haplonema hamulatum Moulton, 1931 is considered a junior synonym of Ichthyobronema conoura Gnedina et Savina, 1930. Philometra ophisterni (only females) is mainly characterised by minute cephalic papillae, a greatly developed anterior oesophageal bulb separated from the cylindrical part of the oesophagus, anterior extension of the oesophageal gland anterior to the nerve ring, and by the character of large caudal projections. This is the first Philometra species recorded from inland fishes in Mexico.  相似文献   

4.
A pentachlorophenol (PCP) wood treatment plant was studied to determine PCP exposure to people by occupation and to the plant by work area. This plant operates on a year-round basis with a 25 percent increase in production from May through October. Approximately 2.5 million board feet of timber are processed annually. Samples were taken in the morning of the second work week of each month for 5 consecutive months. Samples consisted of serum and urine from the employees and air from locations throughout the plant work area. All samples were analyzed for PCP residue. Peripheral blood was used to culture cells to investigate possible chromosomal aberrations.  相似文献   

5.
The following three species of the Philometridae (Nematoda: Dracunculoidea) are described from marine perciform fishes of the Everglades National Park (northern Gulf of Mexico), Florida, U.S.A.: Philometra brevispicula sp. n. (male and females) from the subcutaneous tissue of mouth of the gray snapper Lutjanus griseus (Linnaeus) (Lutjanidae), Philometroides grandipapillatus sp. n. (only females) from pectoral fin muscle of the crevalle jack Caranx hippos (Linnaeus) (Carangidae), and Caranginema americanum Moravec, Montoya-Mendoza et Salgado-Maldonado, 2008 (females) from the subcutaneous fascia of trunk muscle in crevalle jack C. hippos. Philometra brevispicula is mainly characterized by small cephalic papillae of the external circle, the absence of oesophageal teeth and the presence of small caudal projections in gravid female, markedly short spicules (45 microm) in male, and by its location in the host. Philometroides grandipapillatus differs from congeners mainly in the shape of the cephalic region (narrow, conspicuously protruding), large cephalic papillae of the external circle and the absence of caudal projections in female, and by the site of infection in the host. Caranginema americanum is for the first time recorded from the northern Gulf of Mexico.  相似文献   

6.
A preliminary monitoring program was initiated in 1972 to determine ethylenethiourea (ETU) content of the Canadian food supply. Of 167 samples analyzed, 90 were domestic and 77 were imported. Samples were analyzed by electron-capture/gas-liquid chromatography. Thirty-three percent of the samples contained detectable ECU residues; most of these were 0.020 ppm or less. Highest levels, 0.047 and 0.083 ppm, were found in canned spinish and orange peel respectively.  相似文献   

7.
A 2-year study investigated the relationship between the nematicides aldicarb and fosthiazate and populations of plant growth-promoting (PGP) and plant-growth-inhibiting (PGI) bacteria, and root-lesion nematodes and bacteria-feeding nematodes in the root-zone soils of potatoes. Fewer ( P  < 0.05) bacterial genera and species were recovered from aldicarb-treated soils than from the fosthiazate and untreated soils but bacterial population densities were greatest in the aldicarb-treated soils. In potato plantlet bioassays using root-zone bacteria from the three soil sources, bacteria from the aldicarb-treated soils reduced ( P  < 0.01) the mean wet and dry weight of shoots and roots compared with those from the fosthiazate and untreated soils. In the field, fosthiazate (but not aldicarb) significantly increased tuber yields and reduced nematode population densities of Pratylenchus penetrans in roots and soil. Population densities of bacteria-feeding nematodes (primarily Diplogaster lheritieri ) were not affected by either nematicide. Aldicarb appeared to suppress the populations of plant-growth-promoting bacteria that contribute to enhanced growth in potatoes. This is attributed to the long-term use of aldicarb at the trial site, which may have encouraged the selection, or adaptation, of soil microorganisms that degrade carbamate pesticides but do not enhance potato growth.  相似文献   

8.
The effects of infections of Trichinella spiralis on 10 specific-pathogen-free Beagles were examined. Eight puppies received either 100, 500, 1,000, or 5,000 larvae, and 2 adult dogs received 1,000 larvae. Blood was drawn every 4 days, beginning 5 days before infection, for the determination of relative eosinophil numbers. Creatine kinase levels were monitored before infection, two weeks after infection, and one month after infection. The dogs were euthanized 1 month postinfection, and larvae were counted in muscle digests of 10 gram samples of diaphragm, pectoralis superficialis, masseter, biceps brachii, and vastus lateralis. The dogs displayed minor signs of gastrointestinal upset during the first week after infection. The dogs also developed a slight eosinophilia with a magnitude that was dependent on the number of larvae the dog received. All infected dogs, but one that had received 500 larvae, had a positive reaction with larval excretory-secretory products of T. spiralis; adult dogs had the greatest immunologic response. The creatine kinase levels were found not to be related to either the time postinfection or the magnitude of the larval dose. The number of larvae recovered from the muscles (maximum of 70 per gram) was dependent on the dosage of larvae received, but there was no significant predilection of the larvae for any of the five examined muscle groups.  相似文献   

9.
In microplots of nine soils freed from volunteer potatoes and sown for four consecutive years with spring barley, the eggs of five populations of Globodera pallida and four populations of G. rostochiensis declined at annual rates of 12-8-40-5%. One population of G. rostochiensis declined faster than other populations of either species, although average rates of decline did not differ significantly between the two species of Globodera. These results are compared with earlier research and their relevance to control of the nematodes by crop rotation is discussed.  相似文献   

10.
11.
In 1995 two fields in the Netherlands, naturally infested withMeloidogyne hapla (Wageningen) andM. fallax (Baexem), were used to evaluate resistant and susceptibleSolanum genotypes under natural conditions. In April, genotypes were planted in circular microplots. Soil samples were taken and analyzed for the occurrence of second-stage juveniles every six weeks. From August onwards, large differences between resistant and susceptible genotypes in numbers of juveniles were found in the soil. For all resistant wildSolanum genotypes the level of infection in soil at the end of the growing season in October was equal to or lower than at the beginning. Glasshouse experiments were performed with the same genotypes and nematode populations (i.e. originally derived from these fields) and the results were comparable with the observations from the field. It is concluded that resistance, as selected in glasshouse trials, corresponds well with resistant behaviour in the field and that it is worthwhile to transfer the resistance from theseSolanum sources to commercial potato cultivars for successful control of root-knot nematodes.  相似文献   

12.
The present knowledge of the life cycles of nematodes of the family Capillariidae is reviewed and these data are considered from the viewpoint of a new system of the classification of genera in this family (Moravec 1982). An analysis of the relevant literature as also own studies have shown that, in this nematode group, there occur both direct (homoxenous) life cycles without an intermediate host (Baruscapillaria, Pseudocapillaria, Calodium, Pseudocapillaroides, partly also Capillaria, Eucoleus and Aonchotheca) and heteroxenous cycles with participation of obligate intermediate hosts that are usually oligochaetes and rarely fishes (Schulmanela, Pearsonema, partly also Capillaria, Eucoleus and Aonchotheca). A remarkable case is the species Aonchotheca philippinensis, an intestinal parasite of man, with alternative life cycles, i.e. either with participation of the intermediate host or without it (autoinfection), this being dependent on whether eggs or larvae are produced by the female parasites. The transmission of some capillariid species with a direct life cycle may include paratenic hosts (oligochaetes, fishes). Capillariids undergo four moults during their ontogenetic development, the first of which taking place inside the body of the intermediate host in case of heteroxenous cycles. The present knowledge of the biology of nematodes of the Capillariidae is very incomplete; their life cycles have hitherto been studied (in a different extent) in members of only 9 out of 22 presently valid genera (approximately in 7% of recognized capillariid species).  相似文献   

13.
Baseline levels of mercury and chlorinated hydrocarbons were determined for Caribbean coastal biota as part of the U.S. Environmental Protection Agency estuarine monitoring program. Forty-one percent of the 150 environmental samples taken had significant levels of these compounds. Concentrations of chlorinated hydrocarbons suggest spatial and temporal variations within the plant or animal. In some cases residues in biota could be related to the land-use practices in the sampled watershed.  相似文献   

14.
This report summarizes pesticide application and cropping data collected in 1972 from 1,402 agricultural sampling sites in 37 states as part of the National Soils Monitoring Program. Pesticide application data are summarized by all sites, states, and crop. Tables generally give the number of sites reporting, number of times a compound was applied, percent occurrence, and arithmetic mean application rate. Pesticides applied most frequently were atrazine, 2.4-D, captan, and trifluralin. Among selected major crops, pesticides were most frequently applied to sites growing field corn and cotton, least frequently to sites growing alfalfa/bur clover and mixed hay.  相似文献   

15.
本研究从线虫拮抗土壤、线虫拮抗植物根表、普通植物根表,并首次尝试从北方根结线虫雌虫和大豆胞囊线虫胞囊上,分离筛选具有防治危险性线虫病害潜力的生防细菌。在室内试验中,10株细菌菌株对北方根结线虫J2和南方根结线虫具有一定致死作用,其中9株能杀死大豆胞囊线虫J2。在温室试验中,8株菌株对线虫病害的防效在38.2%~66.2%之间。经鉴定,这些细菌分别属于假单胞菌属(Pseudo- monas spp.)和芽孢杆菌属(Bacillus spp.)。  相似文献   

16.
The pathogenicity of steinernematid and heterorhabditid nematodes to caterpillars of the giant looper,Boarmia selenaria (Schiffermüller) (Lepidoptera: Geometridae), was determined under laboratory conditions. High mortality (over 80%) was achieved, in a petri dish bioassay, with a minimum of 20,000 infective juveniles (IJ) ofSteinernema carpocapsae (Filipjev) (=Neoaplectana carpocapsae Weiser), strain ‘All’. The LD50 was 4250 IJ per caterpillar. Similar results were obtained withS. carpocapsae, strain ‘Mexican’,Steinernema sp., strain ‘CR’;Heterorhabditis bacteriophora, strain ‘HP88’; andHeterorhabditis sp., strain ‘IS’. The first and second instars were the most susceptible stages to nematode infection. A laboratory model assay indicated that 80–90% of the caterpillars were killed when they migrated to the soil to pupate; this occurred when IJ were applied to sandy and heavy soils at a concentration of 400 IJ/cm3 soil. A greenhouse test reconfirmed the effectiveness of utilizing the entomopathogenic nematodes in an “ambush” system against caterpillars migrating to the soil.  相似文献   

17.
18.
成飞雪 《植物检疫》2007,21(3):133-136
分离自对湖南郴州、耒阳、张家界地区的病死马尾松样品,采用形态鉴别和分子生物学鉴别相结合的方法对其进行鉴定.形态鉴定结果显示分离检出线虫更符合拟松材线虫特征.同时采用ITS-PCR-RELP方法对病死马尾松中分离线虫进行分子鉴定,ITS区经EcolI和HindⅢ酶切后得到110、160、242、404bp 4条特征带,与拟松材线虫相同,而与松材线虫有明显区别.而且ITS及CoI基因序列信息显示,湖南病死马尾松中分离线虫与松材线虫的同源性分别为92.9%、89.3%,而与拟松材线虫的同源性高达97.2%、95.2%.研究结果表明湖南病死马尾松中分离的线虫为拟松材线虫.  相似文献   

19.
Organochlorine residues in wings of adult mallards and black ducks were monitored during the 1972-73 hunting season. DDE, DDT, DDD, dieldrin, and polychlorinated biphenyls (PCB's) were present in all samples. Mallard wings from Alabama contained the highest mean levels of DDE, DDT, DDD, dieldrin, and PCB's. Mallards and black ducks from the Atlantic Flyway and mallards from the Pacific Flyway contained significantly lower DDE residues than in 1969-70. Black ducks from the Atlantic Flyway contained significantly less dieldrin than in 1969-70, and mallards in the Central and Pacific Flyways contained significantly lower levels of PCB's. As in 1969-70, DDE residues were lowest in the Central Flyway and highest in the Atlantic Flyway. The average PCB level remained unchanged in the Atlantic Flyway but was higher in the Mississippi Flyway than in 1969-70, probably because of the unusually high levels in Alabama samples. All organochlorine residues in black ducks from the Atlantic Flyway significantly correlated. DDE concentrations in mallards from the Atlantic Flyway significantly correlated with those of DDT, DDD, and PCB's.  相似文献   

20.
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