Can additional N fertiliser ameliorate the elevated CO2‐induced depression in grain and tissue N concentrations of wheat on a high soil N background?

Elevated CO₂ stimulates crop yields but leads to lower tissue and grain nitrogen concentrations [N], raising concerns about grain quality in cereals. To test whether N fertiliser application above optimum growth requirements can alleviate the decline in tissue [N], wheat was grown in a Free Air CO₂ Enrichment facility in a low‐rainfall cropping system on high soil N. Crops were grown with and without addition of 50–60 kg N/ha in 12 growing environments created by supplemental irrigation and two sowing dates over 3 years. Elevated CO₂ increased yield and biomass (on average by 25%) and decreased biomass [N] (3%–9%) and grain [N] (5%). Nitrogen uptake was greater (20%) in crops grown under elevated CO₂. Additional N supply had no effect on yield and biomass, confirming high soil N. Small increases in [N] with N addition were insufficient to offset declines in grain [N] under elevated CO₂. Instead, N application increased the [N] in straw and decreased N harvest index. The results suggest that conventional addition of N does not mitigate grain [N] depression under elevated CO₂, and lend support to hypotheses that link decreases in crop [N] with biochemical limitations rather than N supply.     

Photoinduced DNA-protein cross-links and bacterial killing: a correlation at low temperatures

The increased sensitivity of Escherichia coli to killing by ultraviolet irradiation when frozen and the variation in this sensitivity as a function of the temperature during irradiation have been correlated with changes in the amount of DNA that was cross-linked to protein by ultraviolet light. These variations in sensitivity to killing do not correlate with the production of thymine dimers.     

长白猪等生长肥育猪不同营养水平肥育对比试验——Ⅰ.肥育及胴体性状

选择类似条件的长白、大约、长大杂、四元杂断奶仔猪各20头,均等分成两组,分别喂给按美国饲养标准和中国饲养标准配合的日粮,对试验结果进行了最小二乘分析,结果表明,品种组合及营养水平对日增重均有极显著影响,品种组合对后腿比例、瘦肉率、四腿瘦肉率、皮率有显著或极显著影响,对其它性状无显著影响;营养水平除对屠宰率有显著影响外,对其它胴体性状无显著影响,品种组合与营养水平间互作仅在胴体直长、眼肌面积、四腿瘦肉率等少数性状上存在显著影响,采用美国饲养标准饲喂瘦肉型外来品种及其杂种具有饲养成本低,周转快的优点。     

ADAMTS17 mutation associated with primary lens luxation is widespread among breeds

Primary lens luxation (PLL) is a well-recognized, painful and potentially blinding inherited ocular condition in dogs. We screened PLL-affected dogs of 30 different breeds, to identify those which carried a previously described c.1473+1 G>A mutation in ADAMTS17 that is associated with PLL in Miniature Bull terriers, Lancashire Heelers, and Jack Russell terriers. This ADAMTS17 mutation was identified in PLL-affected dogs from 14 additional breeds. PLL-affected dogs from some breeds (most notably the Shar pei and the Brittany spaniel) did not carry the G1473+1A ADAMTS17 mutation, indicating they must suffer from a genetically distinct form of the condition. We also estimated the frequency of this ADAMTS17 mutation in some of the breeds. Our findings indicate the mutation segregates in a large number of different breeds of dog, many of which are terriers or breeds with terrier co-ancestry, but some of which have more diverse origins. Our results also indicate that the mutation is present at high frequency within most of the breeds in which it segregates. In the miniature bull terrier breed estimates of mutation frequency ranged from 0.27 to 0.39, corresponding to 7.3-15.2% PLL-affected dogs in this breed. We also identified an increased risk of PLL associated with heterozygosity at ADAMTS17, suggesting that carriers carry a low risk of developing PLL.     

Auscultation and echocardiographic findings in Bull Terriers with and without polycystic kidney disease

OBJECTIVE: To investigate a possible association between Bull Terrier polycystic kidney disease (BTPKD) and cardiac disease, to determine the prevalence of mitral valve disease (MVD) and left ventricular outflow tract obstruction (LVOTO) in the Australian Bull Terrier population, and to compare auscultation and echocardiography in detection of cardiac disease in Bull Terriers. DESIGN: Ninety-nine Bull Terriers, ranging in age from 8 weeks to 13 years and 11 months were auscultated and examined using renal ultrasonography; 86 were also examined using echocardiography. The prevalence and severity of heart defects in dogs with BTPKD was compared with that in dogs without BTPKD. RESULTS: Nineteen of these 99 dogs were diagnosed with BTPKD. Forty-two percent of Bull Terriers with BTPKD and 28% of those without BTPKD had murmurs characteristic of mitral regurgitation or LVOTO. How recently an animal was descended from an ancestor with BTPKD was associated with presence (P = 0.008) and loudness of a murmur (P = 0.009). Overall, echocardiography detected MVD in 39% of Bull Terriers, with increased prevalence in older animals (P = 0.003). Mitral stenosis was found in eight cases. Fifty-three percent of dogs in this study had evidence of LVOTO, with obstruction consisting of a complex of lesions including dynamic or fixed subvalvular LVOTO, significantly narrowed left ventricular outflow tract or valvular aortic stenosis. Dogs with BTPKD, or those descended from dogs with BTPKD, were more likely to have MVD (P = 0.006), and while LVOTO was not more common in these dogs, if they did have LVOTO, they were more likely to have severe obstruction than dogs with no ancestors with BTPKD (analysed in three ways P = 0.028 to 0.001). In this study, 46% of Bull Terriers without a murmur or arrhythmia had cardiac disease detected on echocardiographic examination. CONCLUSION: Cardiac disease, especially MVD and LVOTO, was common in Bull Terriers in this study, and those with BTPKD had an increased risk of cardiac abnormalities. Auscultation did not detect a significant number of Bull Terriers with cardiac disease.     

Brucella abortus detection by PCR assay in blood, milk and lymph tissue of serologically positive cows

Brucellosis is a highly infectious disease which is diagnosed using serological and microbiological methods. The objective of this study was to assess the viability of using conventional and real-time PCR assays as potential diagnostic tools for the detection of Brucella abortus in naturally infected cows. PCR assays that amplify various regions of the Brucella genome, IS711 genetic element, 31kDa outer membrane protein and 16S rRNA, were optimised using nine known Brucella strains. Real-time PCR was used to examine the detection efficiency of the IS711 assay which was estimated at 10 gene copies. Milk, blood and lymph tissue samples were collected from naturally infected animals. B. abortus was not detected in blood samples collected from naturally infected cows by conventional or real-time PCR, but was detected in a proportion of the culture-positive milk (44%) and lymph tissue (66% - retropharyngeal, 75% - supramammary) samples by the same methods. There was no difference between PCR and bacteriological detection methods. It is unlikely that conventional or real-time PCR will supersede current diagnostic methods for detection of B. abortus in clinical samples.