广东水稻品种对不同白叶枯病菌株的抗性反应

测定了46个水稻品种对60个菌株的抗性反应,可以将这些品种区分为Ⅰ、广谱性抗病,Ⅱ、非广谱性抗病及Ⅲ、无抗性等三种类型。Ⅰ类型品种大多数是外引品种及其杂交衍生品种(系)。Ⅱ类型品种中只有少数具有较好的抗性,大多数都是中等抗病与中等感染的。Ⅲ类型品种都是偏于感病的,但丰产性状较好。为育成更多的抗病新品种,我们认为选择具有广谱抗性的品种作为亲本与高产品种进行组配,另外选择1—2个强菌株作为抗源筛选或杂交组合子代的抗性鉴定菌株,以获得满意的结果。     

Degradation of ioxynil to CO2 in soil

Degradation of ioxynil (4-hydroxy-3,5-diiodobenzonitrile) to CO₂ was detected in a clay loam, high organic matter content soil. The majority of radioactivity was recovered as ¹⁴CO₂ from both ring-labeled and cyano-labeled ioxynil; however, ¹⁴CO₂ was always released from cyano-labeled ioxynil at a much faster initial rate. No ¹⁴CO₂ was released in treated sterile soil, either aerobically or anaerobically. Production of ¹⁴CO₂ from cyanolabeled and ring-labeled ioxynil was greatly inhibited by HgCl₂ (10^?5M), and p-chloromercuribenzoate (5 × 10^?5M), but slightly inhibited by ferricyanide (10^?4M). No ¹⁴CO₂ was evolved from ring-labeled ioxynil under anaerobic conditions. These observations indicated that the degradation of ioxynil to CO₂ in soil was a microbial action and was oxygen dependent. This is consistent with the known mechanism of oxygenases in degrading benzene rings. Anaerobically, a small amount of ¹⁴CO₂ was released from cyano-labeled ioxynil. Thin-layer chromatographic analyses of the culture supernatant revealed that 3,5-diiodo-4-hydroxybenzamide and 3,5-diiodo-4-hydroxybenzoic acid were intermediate metabolites.     

Immunofluorescent cell assay of neonatal calf diarrhea virus.

A reliable plaque assay procedure has not yet been described for the neonatal calf diarrhea virus. Therefore, a previously developed immunofluorescent cell counting procedure was adapted to assay this virus. Adsorption of the virus to bovine kidney cells plateaued at 60 minutes. The optimal staining time was between 20 and 24 hours postinfection. Infected cells begun releasing from the coverslips if the cultures were incubated longer than 24 hours. This procedure has proven successful with virus grown in cell culture as well as virus present in fecal samples.     

Intracranial granular cell tumor in a dog

A 12-year-old female miniature poodle showed a 3-month history of neurological signs. Magnetic resonance imaging disclosed a high intensity tumor mass in the right cerebral hemisphere with compression of the lateral ventricle. At necropsy, a 2 x 3 cm white, friable mass was found in the right ventral pyriform lobe. Microscopically, the tumor cells were large, polygonal to round cells supported by a sparse fibrovascular stroma. The tumor cells typically possessed finely granular, pale eosinophilic cytoplasm with strongly positive periodic acid-Schiff (PAS) reaction. The tumor cells were immunopositive for vimentin, NSE and S-100. Ultrastructurally, the tumor cells showed large amounts of granules in the cytoplasm, and absence of basement membrane. Based on the above-mentioned findings, the intracranial granular cell tumor was diagnosed.     

Bioavailability and pharmacokinetics of florfenicol in healthy sheep

A study on bioavailability and pharmacokinetics of florfenicol was conducted in 20 crossbred healthy sheep following a single intravenous (i.v.) and intramuscular (i.m.) doses of 20 and 30 mg/kg body weight (b.w.). Florfenicol concentrations in serum were determined by a validated high-performance liquid chromatography method with UV detection at a wavelength of 223 nm in which serum samples were spiked with chloramphenicol as internal standard. Serum concentration-time data after i.v. administration were best described by a three-compartment open model with values for the distribution half-lives (T(1/2alpha)) 1.51 +/- 0.06 and 1.59 +/- 0.10 h, elimination half-lives (T(1/2beta)) 18.83 +/- 6.76 and 18.71 +/- 1.85 h, total body clearance (Cl(B)) 0.26 +/- 0.03 and 0.25 +/- 0.01 L/kg/h, volume of distribution at steady-state (V(d(ss))) 1.86 +/- 0.11 and 1.71 +/- 0.20 L/kg, area under curve (AUC) 76.31 +/- 9.17 and 119.21 +/- 2.05 microg.h/mL after i.v. injections of 20 and 30 mg/kg b.w. respectively. Serum concentration-time data after i.m. administration were adequately described by a one-compartment open model. The pharmacokinetic parameters were distribution half-lives (T(1/2k(a) )) 0.27 +/- 0.03 and 0.25 +/- 0.09 h, elimination half-lives (T(1/2k(e) )) 10.34 +/- 1.11 and 9.57 +/- 2.84 h, maximum concentrations (C(max)) 4.13 +/- 0.29 and 7.04 +/- 1.61 microg/mL, area under curve (AUC) 67.95 +/- 9.61 and 101.95 +/- 8.92 microg.h/mL, bioavailability (F) 89.04% and 85.52% after i.m. injections of 20 and 30 mg/kg b.w. respectively.     

Assessing bioterrorism preparedness and response of rural veterinarians: experiences and training needs

Veterinarians play a unique role in emergency preparedness and response, and federal agencies and academic institutions therefore allocate considerable resources to provide training to enhance their readiness. However, the level of preparedness of veterinarians in many rural regions is yet to be improved. This article reports an assessment of the bioterrorism preparedness, specifically the experience and training needs, of rural veterinarians in North Texas. The study employed a cross-sectional design with a study population that included all veterinarians (N = 352) in the 37 counties within Texas Department of State Health Services Regions 2 and 3. Data on veterinarians practicing or residing in the target region were obtained from the Texas State Board of Veterinary Medical Examiners. The response rate was 35% (n = 121). Results indicate that chemical exposure was the condition most frequently seen and treated, followed by botulism and anthrax. The majority (80%) of respondents indicated that they had not previously participated in training related to bioterrorism preparedness, and many (41%) also indicated a willingness to participate in a state health department-initiated bioterrorism response plan. However, only 18% were confident in their ability to diagnose and treat bioterrorism cases. These results suggest that many North Texas veterinarians practicing in rural regions could benefit from additional training in bioterrorism preparedness and response. An area in particular need of further training is the diagnosis and treatment of Category A agents. Federal, state, and local health agencies are urged to increase training opportunities and to make additional efforts to involve veterinarians in bioterrorism preparedness and response.     

Inhibitory effect and mechanisms of an anthocyanins- and anthocyanidins-rich extract from purple-shoot tea on colorectal carcinoma cell proliferation

One newly bred variety of tea cultivar, purple-shoot tea, was selected to evaluate its antiproliferative effects on colorectal carcinoma cells, as well as normal colon cells. The phytochemicals and identified catechins of purple-shoot tea extract (PTE) were significantly higher than that of ordinary tea, especially the anthocyanins (surpassed by 135-fold) and anthocyanidins (surpassed by 3.5-fold). PTE inhibited the proliferation of COLO 320DM (IC(50) = 64.9 μg/mL) and HT-29 (IC(50) = 55.2 μg/mL) by blocking cell cycle progression during the G(0)/G(1) phase and inducing apoptotic death. Western blotting indicated that PTE induced cell cycle arrest by reducing the expression of cyclin E and cyclin D1 in COLO 320DM and the upregulation of p21 and p27 cyclin-dependent kinase inhibitors in HT-29. Two cells treated with PTE also indicated the cleavage of PARP, activation of caspase 3, and an increased Bax/Bcl-2 ratio. Our results showed that PTE is a potential novel dietary agent for colorectal cancer chemoprevention.