Obtaining Wisent early blastocyst in vitro is a basic for protection and creation of biodiversity for this threatened species          下载免费PDF全文

AM Duszewska  P Gręda  M Baraniewicz  W Bielecki  W Niżański  A Partyka  M Tracz  Z Nowak  A Chełmońska‐Soyta  W Olech 《Reproduction in domestic animals》2018,53(3):818-821

Wisent, or European bison (Bison bonasus), is listed as “vulnerable” on the IUCN Red List of Threatened Species and is therefore protected by international law. For the first time, a Wisent embryo has been obtained in vitro. This procedure creates a new opportunity to protect and increase Wisent reproductive potential and thereby opens new possibilities for the establishment of a controlled and broad reserve of the gene pool.  相似文献   

Evaluation of a subcutaneously implanted biodegradable matrix with and without cisplatin in horses     

G. P. Marble  Ken E. Sullins  Barbara K. Powers 《Equine Veterinary Education》2023,35(2):e131-e137

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Soil compaction effects on water status of ponderosa pine assessed through 13C/12C composition     

Gomez GA  Singer MJ  Powers RF  Horwath WR 《Tree physiology》2002,22(7):459-467

Soil compaction is a side effect of forest reestablishment practices resulting from use of heavy equipment and site preparation. Soil compaction often alters soil properties resulting in changes in plant-available water. The use of pressure chamber methods to assess plant water stress has two drawbacks: (1) the measurements are not integrative; and (2) the method is difficult to apply extensively to establish seasonal soil water status. We evaluated leaf carbon isotopic composition (delta13C) as a means of assessing effects of soil compaction on water status and growth of young ponderosa pine (Pinus ponderosa var. ponderosa Dougl. ex Laws) stands across a range of soil textures. Leaf delta13C in cellulose and whole foliar tissue were highly correlated. Leaf delta13C in both whole tissue and cellulose (holocellulose) was up to 1.0 per thousand lower in trees growing in non-compacted (NC) loam or clay soils than in compacted (SC) loam or clay soils. Soil compaction had the opposite effect on leaf delta13C in trees growing on sandy loam soil, indicating that compaction increased water availability in this soil type. Tree growth response to compaction also varied with soil texture, with no effect, a negative effect and a positive effect as a result of compaction of loam, clay and sandy loam soils, respectively. There was a significant correlation between 13C signature and tree growth along the range of soil textures. Leaf delta13C trends were correlated with midday stem water potentials. We conclude that leaf delta13C can be used to measure retrospective water status and to assess the impact of site preparation on tree growth. The advantage of the leaf delta13C approach is that it provides an integrative assessment of past water status in different aged leaves.  相似文献   

Control of fusiform rust of southern pines in the USA     

H. R. Powers 《Forest Pathology》1984,14(7):426-431

Control of fusiform rust in southern pines has improved significantly over the last 10 years. The new systemic fungicide Bayleton provides excellent control in forest tree nurseries with 3 to 5 sprays per season. The topical fungicides previously used had to be applied 35 or more times per season to obtain equivalent control. Disease resistant seedlings have also become available to forest land managers for use in the reforestation programs. The first such seedlings, loblolly pines from specific geographic areas, have reduced the incidence of fusiform rust in young plantations by one-half. Both loblolly and slash pine seedlings from rust-resistant seed orchards are also now becoming available, and they should reduce disease levels significantly. New approaches, such as the development of seedling seed orchards from survivors of artificial inoculation tests should further improve the levels of rust resistance. Current research on the reduction of inoculum on both die pine and oak hosts may provide new management techniques for disease control.  相似文献   

Nitrogen mineralization along an altitudinal gradient: Interactions of soil temperature, moisture, and substrate quality     

Robert F. Powers 《Forest Ecology and Management》1990,30(1-4):19-29

Net soil N mineralization was measured in situ for 2 consecutive years along a 2000-m altitudinal gradient encompassing six vegetation types in northern California. Both anaerobic and aerobic field incubations showed that soil temperature and moisture strongly controlled N release. In sealed container studies, N mineralization per unit of total Kjeldahl N ( ) had a Q₁₀ rate of 2 and varied between 5 and 38 g N/kg when moisture was abundant (anaerobic incubation). However, aerobic mineralization rates fell to between 2 and 22 g N/kg because of summer drought. Aerobic rates were greatest at mid-elevations (the mixed-conifer forest), and were reduced by cold temperatures at higher elevations and by soil drought at lower. The lowest rate found for any site was in a pine plantation scalped of topsoil a decade previously, during site preparation. Open-container incubations involving intact, 15-cm soil cores and ion-exchange resins produced mineralization rates correlated with potential growing days, but not with rates from sealed containers. The forest floor accounted for nearly all the net N mobilized on the coldest site, but only one-half to one-third of the N mobilized on warmer sites. Open containers have important advantages in assessing soil N dynamics.  相似文献   

Efficiency of Two Enucleation Methods Connected to Handmade Cloning to Produce Transgenic Porcine Embryos     

J Li  K Villemoes  Y Zhang  Y Du  PM Kragh  S Purup  Q Xue  AM Pedersen  AL Jørgensen  JE Jakobsen  L Bolund  H Yang  G Vajta 《Reproduction in domestic animals》2009,44(1):122-127

The purpose of our work was to establish an efficient-oriented enucleation method to produce transgenic embryos with handmade cloning (HMC). After 41–42 h oocytes maturation, the oocytes were further cultured with or without 0.4 μg/ml demecolcine for 45 min [chemically assisted handmade enucleation (CAHE) group vs polar body (PB) oriented handmade enucleation (OHE) group respectively]. After removal of the cumulus cells and partial digestion of the zona pellucida, oocytes with visible extrusion cones and/or polar bodies attached to the surface were subjected to oriented bisection. Putative cytoplasts without extrusion cones or PB were selected as recipients. Two cytoplasts were electrofused with one transgenic fibroblasts expressing green fluorescent protein (GFP), while non-transgenic fibroblasts were used as controls. Reconstructed embryos were cultured in Well of Wells (WOWs) with porcine zygote medium 3 (PZM-3) after activation. Cleavage and blastocyst rates were registered on day 2 and day 7 of in vitro culture respectively. Meanwhile, the total blastocyst cell number was counted on day 7. We found that the difference was only observed between blastocyst rates (38.6 ± 2% vs 48.1 ± 3%) of cloned embryos with GFP transgenic fibroblast cells after CAHE vs OHE. With adjusted time-lapse for zonae-free cloned embryos cultured in WOWs with PZM-3, it was obvious that in vitro developmental competence after CAHE was compromised when compared with the OHE method. OHE enucleation method seems to be a potential superior alternative method used for somatic cell nuclear transfer (SCNT) with transgenic fibroblast cells.  相似文献   

Evaluation of ovine herpesvirus type 2 infections, as detected by competitive inhibition ELISA and polymerase chain reaction assay, in dairy cattle without clinical signs of malignant catarrhal fever     

Powers JG  VanMetre DC  Collins JK  Dinsmore RP  Carman J  Patterson G  Brahmbhatt D  Callan RJ 《Journal of the American Veterinary Medical Association》2005,227(4):606-611

OBJECTIVE: To monitor ovine herpesvirus type 2 (OvHV-2) infection status and the association between OvHV-2 infection and development of clinical signs of malignant catarrhal fever (MCF) in cattle. DESIGN: Longitudinal study. ANIMALS: 30 mature adult cows and 18 cattle submitted for necropsy. PROCEDURE: Blood and milk samples were collected at monthly intervals from 30 adult cows for 20 consecutive months. Nasal and ocular swab specimens were also collected during months 9 through 20. Polymerase chain reaction (PCR) assay for detection of OvHV-2 was performed on blood, milk, nasal swab, and ocular swab specimens. Competitive inhibition ELISA (CI-ELISA) for detection of antibodies against MCF viruses was performed on serum samples obtained prior to study initiation and monthly during the last 12 months. Tissues obtained from herdmates without clinical signs of MCF that were submitted for necropsy were analyzed for OvHV-2 DNA via PCR assay for possible sites of latency. RESULTS: Initially, 8 of 30 cows had positive CI-ELISA results. Seroconversion was detected in 4 cows. Ovine herpesvirus type 2 DNA was intermittently detected in blood, milk, nasal secretions, or ocular secretions from 17 of 30 cows. Twenty-one cows had positive CI-ELISA or PCR assay results. No cattle in the study developed clinical signs of MCF. Results of PCR assays performed on tissue samples from 2 of 18 animals submitted for necropsy were positive for OvHV-2. CONCLUSIONS AND CLINICAL RELEVANCE; OvHV-2 infection can occur in cattle without concurrent development of clinical MCF. Ovine herpesvirus type 2 DNA was detected intermittently, suggesting fluctuating viral DNA loads or reinfection in subclinical cattle. A definitive site of latency was not identified from tissues obtained during necropsy.  相似文献   

Massive hepatocellular carcinoma in dogs: 48 cases (1992-2002)     

Liptak JM  Dernell WS  Monnet E  Powers BE  Bachand AM  Kenney JG  Withrow SJ 《Journal of the American Veterinary Medical Association》2004,225(8):1225-1230

OBJECTIVE: To determine clinical signs, diagnostic findings, outcome, and prognostic factors in dogs treated surgically for massive hepatocellular carcinoma (HCC) and compare survival times of surgically and conservatively treated dogs. DESIGN: Retrospective study. ANIMALS: 48 dogs. PROCEDURE: Medical records were examined for clinical signs, diagnostic and surgical findings, and postoperative outcome. Dogs were allocated into surgery and nonsurgery groups depending on whether curative-intent liver lobectomy was performed. Data from the surgical and nonsurgical groups were analyzed to identify prognostic factors and determine and compare rates of tumor control and survival time. RESULTS: 42 dogs were treated surgically, and 6 were managed conservatively. In the surgery group, intraoperative mortality rate was 4.8% with no local recurrence, metastatic rate was 4.8%, and median survival time was > 1,460 days (range, 1 to 1,460 days). High alanine aminotransferase and aspartate aminotransferase activities were associated with poor prognosis. Median survival time for the nonsurgery group was 270 days (range, 0 to 415 days), which was significantly less than that of surgically treated dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Liver lobectomy is recommended for dogs with massive HCC because tumor-related mortality rate was 15.4 times higher in dogs in the nonsurgery group, compared with the surgery group. Tumor control was excellent after surgical resection with no local recurrence and a low metastatic rate. Prognostic factors were identified, but their clinical relevance was uncertain because only 9.5% of dogs in the surgery group died as a result of their disease.  相似文献   

Graduates in Veterinary Science     

Martin AM  Currie E. 《Australian veterinary journal》2004,82(8):496-496

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Preputial damage and lateral penile displacement during castration in a degu     

Powers MY  Campbell BG  Finch NP 《Journal of the American Veterinary Medical Association》2008,232(7):1013-1015

CASE DESCRIPTION: A 2-month-old male degu was treated for preputial damage and lateral penile displacement that occurred during attempted castration. CLINICAL FINDINGS: Bruising and swelling of the prepuce and severe edema to the left of the prepuce were evident. The penis could not be extruded from the prepuce. Radiography revealed a large bladder. Contrast medium injected into the prepuce filled the peripreputial subcutaneous tissues. TREATMENT AND OUTCOME: During surgical exploration through a peripreputial approach, the penis was found to be completely separated from the prepuce and located in the adjacent subcutaneous tissue. The penis was repositioned in the prepuce and anchored with a suture at its base. The following day, the preputial orifice was crusted over, urine was leaking from the incision, and the penis could not be extruded from the prepuce. The anchoring suture was removed, and the tip of the penis was sutured to the preputial orifice so that the penis protruded slightly from the prepuce. Urination was normal after the second surgery. Two years later, the preputial orifice remained adhered to the distal portion of the penis and the exposed penile tissue was healthy. CLINICAL RELEVANCE: Penile displacement from the prepuce is an unusual complication of castration in degus. The surgical technique used in this animal may be an effective means of repair. Permanent exposure of the tip of the penis may be well-tolerated in degus.  相似文献