梨韧皮部特异表达启动子AtSUC2驱动下的GUS基因的转化和表达

 以 ‘Old Home’ 梨无菌苗叶片为外植体, 利用根癌农杆菌介导将专一在韧皮部表达启动子AtSUC2 驱动下的GUS 基因转入 ‘Old Home’中。筛选出了‘Old Home’ 梨叶片高效遗传转化的最佳条件：农杆菌和外植体在液体培养基上共培比在固体培养基上共培转化率提高5倍。 PCR分析和Southern 杂交鉴定表明GUS 基因已整合到转基因植株的基因组中,组织化学检测和Western 杂交鉴定证明了GUS 基因在转基因植株韧皮部中的表达。     

IMAGING DIAGNOSIS—MAGNETIC RESONANCE IMAGING OF DIFFUSE LEPTOMENINGEAL OLIGODENDROGLIOMATOSIS IN A DOG WITH “DURAL TAIL SIGN”

A case of diffuse leptomeningeal oligodendrogliomatosis affecting the brain and spinal cord of a dog is presented. A 7.5‐year old, male neutered Staffordshire bull terrier presented for evaluation of a chronic history of tetraparesis and seizures, with a multifocal neuroanatomical localization was determined. Extra‐axial intradural lesions with an atypical presentation of a dural tail sign were seen on MRI. Histologically, the lesions were consistent with leptomeningeal oligodendrogliomatosis. To the authors’ knowledge, a dural tail sign has not previously been reported as an MRI characteristic of diffuse leptomeningeal oligodendrogliomatosis in dogs.     

Development and evaluation of a diagnostic PCR for Mycoplasma synoviae using primers located in the intergenic spacer region and the 23S rRNA gene

Mycoplasma synoviae (Ms) is an important pathogen of poultry, causing economic losses to this industry. Early and reliable diagnosis is a key to controlling the spread of this organism. In this study, a polymerase chain reaction with one primer based on the intergenic spacer region (ISR) was validated for detection of Ms. The ISR primer was paired with a general primer from within the 23S rRNA gene. The PCR primers were tested with the 22 other recognised avian Mycoplasma species to check the specificity and with 21 field isolates of Ms from various hosts and countries, and with several swab samples. The PCR appeared to be specific and sensitive. Four different sample preparation methods were compared for use in this PCR, and the amplification protocol was compared with three others, confirming the comparative sensitivity of the new PCR.     

Ambient-temperature isolation of a compound with a boron-boron triple bond

Homoatomic triple bonds between main-group elements have been restricted to alkynes, dinitrogen, and a handful of reactive compounds featuring trans-bent heavier elements of groups 13 and 14. Previous attempts to prepare a compound with a boron-boron triple bond that is stable at ambient temperature have been unsuccessful, despite numerous computational studies predicting their viability. We found that reduction of a bis(N-heterocyclic carbene)-stabilized tetrabromodiborane with either two or four equivalents of sodium naphthalenide, a one-electron reducing agent, yields isolable diborene and diboryne compounds. Crystallographic and spectroscopic characterization confirm that the latter is a halide-free linear system containing a boron-boron triple bond.     

Comparison of ultrasonography, radiography and a single computed tomography slice for the identification of fluid within the tympanic bulla of rabbit cadavers

Evaluation of the tympanic bulla (TB) in cases of otitis media in the rabbit can be a diagnostic challenge, although a feature often associated with the condition is the accumulation of fluid or material within the TB. Randomly selected TB from 40 rabbit cadavers were filled with a water-based, water-soluble jelly lubricant. A dorsoventral radiograph and single computed tomography (CT) slice were taken followed by an ultrasound (US) examination. Image interpretation was performed by blinded operators. The content of each TB was determined (fluid or gas) using each technique and the cadavers were frozen and sectioned for confirmation. CT was the most accurate diagnostic method, but US produced better results than radiography. Given the advantages of US over the other imaging techniques, the results suggest that further work is warranted to determine US applications in the evaluation of the rabbit TB and clinical cases of otitis media in this species.     

A novel phenotype for Lardon dwarfism in miniature Bos indicus cattle suggests that the expression of growth hormone receptor 1A in liver is required for normal growth

Mutations within the growth hormone receptor (GHR) gene that lead to an inactivated or truncated GHR protein cause abnormal growth and small adult size in a variety of species (Laron dwarfism). We studied a line of miniature Bos indicus cattle that have phenotypic (small mature size) and endocrine (increased blood growth hormone and decreased blood insulin-like growth factor-I concentrations) similarities to Laron dwarfs. Liver mRNA from miniature and control cattle was used to amplify a cDNA within the coding region of the GHR. The miniature cattle had GHR mRNA size (determined by Northern blot) and cDNA sequence that were similar to control cattle and, therefore, were unlike most Laron dwarf genotypes in which the GHR gene is mutated. Amounts of mRNA from liver as well as muscle (superficial neck and longissimus) were analyzed by ribonuclease protection assay for IGF-I, total GHR, GHR 1A (inducible, liver-specific GHR mRNA), and GHR 1B (constitutive GHR mRNA). Four control and five miniature bulls were tested. As expected, liver IGF-I mRNA was decreased in the miniature cattle (approximately 12% of control; P < 0.01). The amount of the total GHR as well as GHR 1A mRNA were also decreased in liver (17% and 19% of control, respectively; P < 0.01). Other GHR mRNA, including GHR 1B mRNA, were similar for miniature and control cattle. In muscle, there was a tendency (P < 0.10) for decreased IGF-I mRNA and increased GHR mRNA in miniature compared with control cattle. In summary, a novel phenotype for Laron dwarfism in Bos indicus cattle was associated with underexpression of GHR 1A mRNA, but not other GHR mRNA variants in liver. In addition to decreased GHR 1A mRNA, the miniature cattle had decreased liver IGF-I mRNA. Full expression of GHR 1A in liver, therefore, may be required for full liver IGF-I expression and normal growth.     

Genetic and nongenetic influences on vigor at birth and preweaning mortality of purebred and high percentage Brahman calves

The objectives of this study were to assess the risk associated with proportion Brahman inheritance, cow age, dystocia, and birth date weather conditions on calf vigor at birth (n = 3,253) and preweaning mortality (n = 3,631), and to estimate heritabilities for these traits. Calves that had poor vigor at birth and calves that died before weaning were coded 1, and those that had adequate birth vigor or survived to weaning were coded 0. Traits were analyzed using GLM. Year (1951 to 2002), cow age, calfgender, minimum temperature on date of birth (two levels: < 5.6 degrees C; or > 5.6 degrees C), and occurrence of dystocia were main effects in models. The proportion of Brahman inheritance in calves was modeled as a covariate. Males had greater odds of poor birth vigor (odds ratio = 1.44, 95% confidence interval = 1.14 to 1.82). The odds of death before weaning for steers relative to heifers approached significance (P = 0.07; odds ratio 1.41, 95% confidence interval 0.97 to 2.04). Calves born to young (3-yr-old) or very old (13 yr or older) cows had greater (P < 0.05) odds of poor vigor and death before weaning than calves of 5-yr-old cows. Calves with difficult births had 2.59 times greater odds of poor birth vigor (95% confidence interval 1.40 to 4.79) and 12.9 times greater odds of death before weaning (95% confidence interval 8.14 to 20.39) than calves born with no dystocia. Calves born on days with minimum temperatures of 5.6 degrees C or less had greater odds of poor vigor (odds ratio 1.97, 95% confidence interval 1.50 to 2.59) and of death before weaning (odds ratio 1.64, 95% confidence interval 1.27 to 2.13) than did calves born on days with higher minimums. The occurrence of rainfall on date of birth did not influence calf vigor at birth or preweaning mortality (P > 0.85). Purebred Brahman calves had 24.7 times greater odds (95% confidence interval 8.23 to 73.97) of poor vigor than 2/3 Brahman calves. The regression coefficient estimate for fraction of Brahman inheritance approached significance (P = 0.07) for preweaning mortality. Estimates of direct and maternal heritability were 0.09 +/- 0.05 and 0.10 +/- 0.04 for birth vigor, and 0.06 +/- 0.05 and 0.09 +/- 0.04, respectively, for preweaning mortality. Some exploitable genetic variation exists for these traits, but management of other factors may yield more immediate improvement than selection.     

Prevalence of hemangiosarcoma in anemic dogs with a splenic mass and hemoperitoneum requiring a transfusion: 71 cases (2003-2005)

OBJECTIVE: To determine prevalence of splenic hemangiosarcoma in anemic dogs with a splenic mass and hemoperitoneum requiring a transfusion and to identify factors that could differentiate between dogs with hemangiosarcoma and dogs with other splenic masses at the time of hospital admission. DESIGN: Retrospective case series. ANIMALS: 71 dogs. PROCEDURES: Medical records, blood bank logs, and histologic reports of dogs with a splenic mass and hemoperitoneum that required a transfusion between 2003 and 2005 were reviewed. Dogs that received a transfusion of packed RBCs, were splenectomized, and had a definitive histologic diagnosis were included. RESULTS: Signalment of dogs was similar to that in other reports. Malignant splenic neoplasia was identified in 54 of 71 (76.1%) dogs, whereas 17 of 71 (23.9%) dogs had a benign splenic lesion. Of 54 dogs with malignant splenic neoplasia, 50 (92.6% [70.4% of all dogs]) had splenic hemangiosarcoma. In addition, dogs with splenic hemangiosarcoma had significantly lower total solids (TS) concentrations and platelet counts at admission. Finally, hemoperitoneum was strongly associated with a diagnosis of splenic hemangiosarcoma. CONCLUSIONS AND CLINICAL RELEVANCE: In this clinical population of dogs, prevalence of hemangiosarcoma was higher than in other studies. Dogs with hemangiosarcoma in this study had significantly lower TS concentrations and platelet counts at the time of admission, compared with values for dogs with other splenic masses. No other markers were useful in differentiating dogs with hemangiosarcoma. It is important to discuss the prevalence of and poor prognosis associated with hemangiosarcoma with owners when they are contemplating whether to proceed with treatment.