Survey of potato spindle tuber viroid in seed potato growing areas of the United States     

Mike Sun  Susan Siemsen  William Campbell  Pablo Guzman  Robert Davidson  Jonathan L. Whitworth  Terry Bourgoin  Jeff Axford  Willem Schrage  Gary Leever  Alan Westra  Steve Marquardt  Hossien El-Nashaar  Jeff McMorran  Oscar Gutbrod  Tom Wessels  Robert Coltman 《American Journal of Potato Research》2004,81(3):227-231

Fourteen United States (U.S.) seed potato certification agencies surveyed all U.S. seed potato growing areas for presence of the potato spindle tuber viroid (PSTVd). The survey included general surveillance, which involved searching for the occurrence of PSTVd in state seed potato certification records from 1990 through 2000, and a field survey, which involved testing selected crops for PSTVd infection by nucleic acid dot blot hybridization during 1999 through 2001. No PSTVd incident was documented in any of the state certification records, nor was PSTVd detected in the field surveys. All U.S. seed-growing areas were determined to be free of PSTVd. It is concluded that PSTVd has been eradicated and freedom from potato spindle tuber viroid has been successfully maintained in all of the seed potato growing areas in the United States.  相似文献   

黑麦日粮中添加不同酶制剂对肉仔鸡生产性能及肠道食糜粘度的影响   总被引：8，自引：0，他引：8  

张志群  R.R.Marquardt  W.Guenter  韩正康 《中国畜牧杂志》1998,34(1):3-6

本文用１８０只肉仔鸡,进行饲养试验,研究黑麦日粮添加４种不同酶制剂,ＮＱ、ＲＭ１、ＲＭ２和ＲＭ３,对肉仔鸡的生产性能以及肠道食糜及泄殖腔粪样粘度的影响。酶制剂ＮＱ和ＲＭ１含有高的木聚糖酶活（７７００ＩＵ／ｇ,３４５０ＩＵ／ｇ）能极显著改进（Ｐ＜０．０１）增重（８．４％,１６．０％）和饲料转化率（１５．４％,１４．４％）,ＲＭ２,含有相对低的木聚糖酶（６０ＩＵ／ｇ）和相对高的阿拉伯呋喃糖苷酶活（５．３ＩＵ／ｇ）,产生类似的效果（Ｐ＜０．０１）：增重提高１０．５％,饲料转化率提高１１．８％,然而ＲＭ３,由于含木聚糖酶活较低（５ＩＵ／ｇ）和较高的蛋白酶活（８０ＩＵ／ｇ）,则对增重无效,但亦可改善饲料转化率（６．４％,Ｐ＜０．０５）。上述酶制剂在降低肠道食糜和泄殖腔粪样粘度方面与增重和饲料转化率有相同的趋势。一般说来,日粮中添加的酶量与食糜相应的粘度成倒数关系。这些结果证明：具有较高木聚糖酶活的酶制剂能明显降低肠道食糜和泄殖腔粪样的粘度,从而改善饲喂黑麦日粮肉仔鸡的生产性能。  相似文献   

Studies of the tolerance and disposition of ochratoxin A in young calves     

O Sreemannarayana  A A Frohlich  T G Vitti  R R Marquardt  D Abramson 《Journal of animal science》1988,66(7):1703-1711

Tolerance to and disposition of ochratoxin A (OA) were compared in preruminant and ruminant calves. Two preruminant calves receiving 4.0 mg OA/kg body weight by stomach tube died; one of two calves receiving 1.0 mg/kg body weight survived. At a dose of .5 mg OA/kg body weight both calves survived. The administered OA was converted mainly (80.1 to 88.9%) to ochratoxin-alpha (O alpha), which was found only in urine; the remaining OA appeared in the urine (3.2 to 3.3%) and feces (7.8 to 10.0%). In the one surviving calf of two given .25 mg OA/kg body weight i.v., nearly twice as much OA was excreted in the feces (44.5%) as in the urine (25.0%); no O alpha was found in urine or feces. All four calves with functional rumens receiving OA orally, 2.0 mg/kg body weight, survived without overt ill effects. Approximately 90% of the OA was excreted as O alpha, with approximately four to eight times more in the urine than in the feces; OA was low in the urine or feces. A plot of the serum OA concentration-time data revealed a prominent, sustained, secondary peak, which was described adequately by a four-exponential equation with two apparent absorption components. Accordingly, OA initially was absorbed rapidly by a first-order rate process (ka = .496/h), and following a considerable delay (tlag = 12.84 h) absorption appeared to resume by a second, slower, first-order rate process (ka = .127/h). The second absorption phase was best explained as being due to enterohepatic cycling of OA.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

Use of Lathyrus Sativus L. (var. seminis albi) as a foodstuff for poultry     

R. K‐C. Low  R. G. Rotter  R. R. Marquardt  G. C. Campbell 《British poultry science》1990,31(3):615-625

1. The gross composition of Lathyrus sativus was examined, and its use as a foodstuff for growing chicks over time as well as the influence of supplementation with certain amino acid combinations were studied.

2. Chemical analyses indicated lathyrus to be high in crude protein with adequate concentrations of most inorganic elements and amino acids except methionine and cystine.

3. The performance of growing chicks fed 800 g/kg lathyrus over a four week period was significantly poorer than those given a wheat/ soyabean meal‐based diet (P<0.05), but there appeared to be some adaptation to the antinutritive factors in the lathyrus.

4. Chick performance was markedly improved by dietary methionine supplementation alone (P<0.05); it was slightly better when trypto‐phan was added in combination with methionine but was still inferior to that on a wheat/soyabean meal‐based diet.

5. Supplementation of lathyrus‐based diets with methionine and tryto‐phan may improve chick performance, but it is not sufficient to overcome the effects of antinutritive factors in the legume.  相似文献   

Monitoring of effects induced by recombinant equine interferon-beta 1 in whole blood and separated fractions of peripheral blood of horses.     

J Marquardt  J Heymer  H Heinz  E Deegen  G R Adolf  W Leibold 《Zentralblatt für Veterin?rmedizin. Reihe B. Journal of veterinary medicine. Series B》1992,39(5):327-336

Interferon is known to induce antiviral mechanisms and to exert immunoregulatory capacities on various cell types. The antiviral capacity of recombinant equine interferon-beta 1 (rEqIFN-beta 1) is most sensitively monitored by indirect quantitation of multiplication of vesicular stomatitis virus (VSV) in blood cells of horses. As few as 0.5 pg rEqIFN-beta 1/ml can be assessed by means of 90% reduction of VSV-replication in whole blood (w.b.) as well as in isolated mononuclear blood cells (MNC) in spite of individual variations. The immunoregulatory influence of 20-50 pg rEqIFN-beta 1/ml is sufficient to cause at least a 50% reduction of mitogen-induced lymphocyte proliferation in MNC, while higher concentrations are needed in w.b. Of the mitogens tested the best stimulation of proliferation on the equine lymphoid cells was obtained with staphylococcal enterotoxin B (SEB). Release of reactive oxygen species (ROS) from phagocytic cells in w.b. or from isolated polymorphonuclear cells (PMN) as monitored by chemiluminescence (CL) does not seem suitable for evaluation of rEqIFN-beta 1-induced immunoregulation as only very high rEqIFN-beta 1-concentrations (10(3)-10(4) pg/ml) result in a minute increase (up to 20%) of CL. Comparative studies on w.b. and isolated leukocyte fractions from identical specimens of individual horses suggest that monitoring of antiviral and distinct immunoregulatory capacities of rEqIFN-beta 1 can be performed on w.b. without loss of information and sensitivity as compared to isolated MNC.  相似文献   

Use of a Compounded Long-Acting Progesterone Formulation for Equine Pregnancy Maintenance     

Dirk K. Vanderwall DVM  PhD  Dipl. ACT  Jessica L. Marquardt MS  Gordon L. Woods DVM  PhD  Dipl. ACT 《Journal of Equine Veterinary Science》2007,27(2):62-66

The objective of this study was to test the efficacy of a compounded long-acting progesterone formulation (BioRelease P4 LA 150; BETPHARM, Lexington, KY) containing 150 mg progesterone/ml for pregnancy maintenance in mares after prostaglandin (PG) F_2α-induced luteolysis. On day 18 of gestation, mares were randomly assigned to one of four groups (n = 7/group): (1) saline-treated control (Saline); (2) PGF_2α-treated control (PGF); (3) PGF_2α- and Regu-Mate-treated (Regu-Mate); and (4) PGF_2α- and BioRelease P4 LA 150-treated (BioRelease). On day 18, Saline mares received 1 ml sterile saline IM, whereas PGF, Regu-Mate, and BioRelease mares received 250 μg cloprostenol IM. Beginning on day 18, Regu-Mate mares received 10 ml Regu-Mate orally once daily and BioRelease mares received 10 ml BioRelease P4 LA 150 containing 150 mg/ml progesterone IM once every 7 days; treatments were continued until day 45 or until pregnancy loss occurred. Pregnancy diagnosis was performed every 3 days between days 18 and 45 (or until pregnancy loss). Pregnancy loss was defined as complete absence of a discernible embryonic vesicle as determined with transrectal ultrasonography. Pregnancy loss rates between days 18 and 45 were: Saline, 1/7; PGF, 7/7; Regu-Mate, 1/7; and BioRelease, 0/7. The pregnancy loss rate was higher (P < .01) in PGF_2α-treated control mares compared with the other groups. There were no differences (P > .1) in pregnancy loss rates among the saline-treated control, Regu-Mate-treated, and BioRelease P4 LA 150-treated mares. These results indicate that intramuscular administration of BioRelease P4 LA 150 containing a total of 1.5 g progesterone every 7 days provided a sufficient level of progesterone to maintain pregnancy between days 18 and 45 of gestation in mares that lacked an endogenous source of progesterone; therefore, this long-acting formulation of progesterone appears to be an efficacious and suitable alternative to currently available progesterone formulations that require daily administration.  相似文献   

Infectious bronchitis: detection of viral antigen in eggs and antibodies in chicken serum by complement-fixation     

W W Marquardt 《Avian diseases》1974,18(1):105-110

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A nucleotide deletion causing a translational stop in the protease reading frame of bovine leukaemia virus (BLV) results in modified protein expression and loss of infectivity     

Blankenstein P  Bondzio A  Fechner H  Beier D  Marquardt O  Looman AC  Ebner D 《Journal of veterinary medicine. B, Infectious diseases and veterinary public health》2000,47(5):361-371

Bovine leukaemia virus (BLV) is an oncogenic retrovirus that causes B-cell lymphocytosis and in the terminal stage of the disease lymphosarcoma. The comparison of the previously published BLV provirus sequence from Belgium, Australia and Japan showed that the protease gene (prt) of the Australian and the Japanese isolate contain a nucleotide deletion when compared to the Belgian isolate. Because all these proviruses were isolated from tumour tissue, the prt gene of functionally active and infectious proviruses from peripheral blood leucocytes (PBLs) of BLV-infected cattle and from BLV-infected fetal lamb kidney cells were sequenced. The only variations between these sequences and the Belgian isolate consist of nucleotide substitutions. The delection of one nucleotide of the prt gene of the Japanese and the Australian BLV tumour isolate caused a changed reading frame and a premature translational stop. It was shown that the Japanese provirus is non-infectious in transfected cell culture and in injected sheep. To analyse the impact of the prt mutation on viral protein expression and infectivity, the prt region of the Japanese provirus was exchanged with the prt region from the Belgian provirus. The resulting pBLVprtbelg was infectious in transfected cells and enabled the expression of gag and gag-precursor proteins. One sheep was injected with this mutated provirus and became positive in BLV-PCR, but no seroconversion was developed. The prt mutation of the Japanese tumour isolates was shown to be responsible for the loss of infectivity and changed viral expression. These results and the occurrence of this mutation in only two isolates from lymphosarcoma indicate a possible relation between the prt mutation and the induction of cell transformation.  相似文献   

Antigenic variation among foot-and-mouth disease virus type A field isolates of 1997-1999 from Iran   总被引：3，自引：0，他引：3  

Marquardt O  Freiberg B 《Veterinary microbiology》2000,74(4):377-386

The sequences of the antigenically relevant capsid proteins VP1-3 of 10 isolates obtained during an epizootic of serotype A foot-and-mouth disease virus in Iran, and collected within two and a half years, were found to be highly similar. However, each isolate differed by at least one amino acid from all others. This prompted us to analyze the immunological reactivity of the isolates. To this end, monoclonal antibodies (mAbs) against one isolate were generated and characterized with regard to neutralizing activity and reactivity with trypsinized virus. These mAbs as well as others raised against A22 virus were used for antigen profiling. This distinguished four antigenic conditions among the isolates and 16 reactivities among the mAbs. These findings, together with the observed sequence differences indicated the location of several epitopes. Many mAbs recognized the minor antigenic sites on VP2 and 3 and some the major site, the GH-loop of VP1. One epitope was composed of residues of the capsid proteins VP1 and 2.  相似文献   

Segregation of axial motor and sensory pathways via heterotypic trans-axonal signaling     

Gallarda BW  Bonanomi D  Müller D  Brown A  Alaynick WA  Andrews SE  Lemke G  Pfaff SL  Marquardt T 《Science (New York, N.Y.)》2008,320(5873):233-236

Execution of motor behaviors relies on circuitries effectively integrating immediate sensory feedback to efferent pathways controlling muscle activity. It remains unclear how, during neuromuscular circuit assembly, sensory and motor projections become incorporated into tightly coordinated, yet functionally separate pathways. We report that, within axial nerves, establishment of discrete afferent and efferent pathways depends on coordinate signaling between coextending sensory and motor projections. These heterotypic axon-axon interactions require motor axonal EphA3/EphA4 receptor tyrosine kinases activated by cognate sensory axonal ephrin-A ligands. Genetic elimination of trans-axonal ephrin-A --> EphA signaling in mice triggers drastic motor-sensory miswiring, culminating in functional efferents within proximal afferent pathways. Effective assembly of a key circuit underlying motor behaviors thus critically depends on trans-axonal signaling interactions resolving motor and sensory projections into discrete pathways.  相似文献