Use of Brucella abortus vaccine strain RB51 in pregnant cows after calfhood vaccination with strain 19 in Argentina

One hundred and seven pregnant cows, which had been calfhood vaccinated with Brucella abortus strain 19 (S-19) were revaccinated with either S-19 or strain RB51 (S-RB51). All S-19-revaccinated animals seroconverted, while none of the RB51-revaccinated animals seroconverted. Two out of 25 (8%) S-19-revaccinated animals aborted, while none of the 57 RB51-revaccinated group aborted. Four of the S-19-revaccinated animals shed S-19 in the milk for at least 7 days, while only 1 cow shed S-RB51 for at least 3 days (but <7 days) post-parturition. Revaccination of strain 19 calfhood-vaccinated, pregnant cattle with S-RB51 appears to be a safe procedure with no diagnostically negative consequences.     

Use of Brucella abortus vaccine strain RB51 in pregnant cows after calfhood vaccination with strain 19 in Argentina

One hundred and seven pregnant cows, which had been calfhood vaccinated with Brucella abortus strain 19 (S-19) were revaccinated with either S-19 or strain RB51 (S-RB51). All S-19-revaccinated animals seroconverted, while none of the RB51-revaccinated animals seroconverted. Two out of 25 (8%) S-19-revaccinated animals aborted, while none of the 57 RB51-revaccinated group aborted. Four of the S-19-revaccinated animals shed S-19 in the milk for at least 7 days, while only 1 cow shed S-RB51 for at least 3 days (but <7 days) post-parturition. Revaccination of strain 19 calfhood-vaccinated, pregnant cattle with S-RB51 appears to be a safe procedure with no diagnostically negative consequences.     

Fine-mapping of quantitative trait loci for body weight and bone traits and positional cloning of the RB1 gene in chicken

Previously, a quantitative trait locus (QTL) that affects body weight (BW) at 4-12 weeks of age and carcass weight at 12 weeks of age had been mapped on chicken chromosome 1. After including more markers and individuals, the confidence interval was narrowed down to approximately 5.5 Mbps and located this QTL near a microsatellite marker (ADL328). This QTL is the same as the QTL for 12 bone traits, including metatarsus length and metatarsus circumference at 4, 6, 8, 10 and 12 weeks of age and keel length and metatarsus claw weight at 12 weeks of age, that was identified using the same population. In the current study, 1010 individuals from the Northeast Agricultural University F(2) resource population were used and 14 single-nucleotide polymorphism (SNPs) around ADL328 were developed to construct haplotypes, and an association analysis was performed to fine-map the QTL. The haplotypes were constructed on the basis of a sliding 'window', with three SNP markers included in each 'window'. The association analysis results indicated that the haplotypes in 'windows' 6-12 were significantly associated with BW and bone traits and suggested that the QTL for BW and bone traits was located between SNP8 and SNP14 or was in linkage disequilibrium with this region. The interval from SNP8 to SNP14 was approximately 400 kbps. This region contained five RefSeq genes (RB1, P2RY5, FNDC3A, MLNR and CAB39L) on the University of California Santa Cruz website. The RB1 gene was selected as a candidate gene and five SNPs were identified in the gene. The association results indicated that the RB1 gene was a major gene for BW and bone traits. The SNPs g.39692 G>A and g.77260 A>G in RB1 gene might be two quantitative trait nucleotides for BW and bone traits.     

马铃薯抗晚疫病基因R3a、R1和RB在番茄中的表达

 晚疫病由疫霉菌( Phytophthora infestans) 引起, 主要侵染番茄和马铃薯等茄科作物, 造成巨大的经济损失。马铃薯已有5个抗晚疫病基因被克隆。为了研究已克隆的马铃薯抗晚疫病基因是否在番茄中起作用, 将马铃薯的抗晚疫病基因R3a、R1和RB 通过农杆菌介导法分别导入番茄品种Moneymaker中。筛选得到的再生植株经PCR检测结果表明, 目的基因已整合入番茄基因组; 转基因番茄离体叶片接种验证结果表明, 接种马铃薯晚疫病菌株8914829 (即小种0) , 转基因番茄产生了抗病的过敏反应(HR反应) 。为了验证转基因番茄是否对番茄晚疫病菌株产生抗性, 用番茄晚疫病的主流小种和强致病力菌株共5个菌株接种转基因番茄植株, 结果表明转R3a和R1 基因的番茄对部分番茄晚疫病菌株能够产生抗性, RB转基因植株叶片对5个番茄晚疫病菌株均产生抗性。该研究为番茄抗晚疫病的基因工程育种开辟了新的途径。     

Precision of soil moisture sensor irrigation controllers under field conditions

New soil moisture sensor systems (SMSs) for irrigation control have been commercialized in recent years. However, limited research has been carried out to evaluate their precision to measure the volumetric soil water content (θ). The objectives of this research were to: (a) determine the relationship between θ and the θ sensed by four commercially available SMSs, (b) quantify the proportion of scheduled irrigation cycles (SICs) that the SMSs bypassed, and (c) determine the θ at which SICs were allowed or bypassed. Sensors from brands Acclima, Rain Bird, Irrometer, and Water Watcher were buried at 7-10 cm depth, on plots with common bermudagrass [Cynodon dactylon (L.) Pers.]. A calibrated ECH₂O probe was also installed in every plot, at the same depth, to monitor θ continuously. When comparing the ECH₂O readings with θ sensed by the SMSs, significant correlations were found for the three Acclima RS500 (AC) systems tested, and for two of the three systems of Irrometer Watermark 200SS/WEM (IM) and Rain Bird MS-100 (RB). Most of the SMS-based treatments bypassed the majority of the SICs during rainy periods, and allowed irrigation during the dry periods. On average, 71% of the SICs were bypassed by the SMS treatments, without detriment to the turfgrass quality. However, most of the SMSs were not found to be precision instruments, because sometimes they bypassed SICs and sometimes they did not, even when reading the same or a lower θ. Considering the average θ range of over which the different SMS treatments always allowed or always bypassed irrigation, brand AC resulted in the significantly narrowest range (1.4%) followed by RB (3.2%), suggesting that they were more consistent and precise in measuring θ than Water Watcher DPS-100 (WW) and IM (7.4 and 7.8%, respectively). These results are consistent with the reported water savings achieved by these SMSs in related studies.     

不同用种量对固氮甘蔗品种RB72-454植株生育及经济性状的影响

在坝地和坡地设置固氮甘蔗品种RB 72-454用种量分别为8000芽／667m^2，9000芽／667m^2和10000芽／667m^2（ck）3种处理，经新植和宿根试验结果表明：品种出苗率、分蘖率、茎高、茎径、产量、蔗糖分均随用种量增大而呈下降趋势。用种量8000芽／667m^2坝地甘蔗产量8859kg／667m^2，蔗糖分15．59％，含糖量1174kg／667m^2，节本增收322．9元／667m^2，坡地产量7351kg／667m^2，蔗糖分15．6％，含糖量974kg／667m^2，节本增收349．9元／667m^2。用种量8000芽／667m^2有利品种植操生育、经济性状提高和节本增收。     

Evaluation of brucellosis RB51 vaccine for domestic water buffalo (Bubalus bubalis) in Trinidad

Thirty-two young domestic water buffalo (Bubalus bubalis) were obtained from a brucellosis-free farm to determine effectiveness of RB51 vaccination for prevention of Brucella infection under natural-exposure conditions in Trinidad. Study animals (20 males and 12 females 5–20 months old) were assigned to vaccination or control groups, using a block randomization design ensuring equal sex distributions between groups. The vaccination group received commercially available RB51 at the recommended calfhood dose of (1.0–3.4)×10¹⁰ colony-forming units (CFU) and controls received 2 ml sterile saline. Vaccination did not result in positive serologic results as measured by four traditional agglutination tests: standard tube agglutination test (STAT), standard plate agglutination test (SPAT), buffered plate agglutination test (BPAT), and card agglutination. Study animals were maintained in a brucellosis-positive herd in southern Trinidad with an estimated 56% prevalence to allow for natural exposure to B. abortus, which was evaluated using STAT, SPAT, BPAT, and card tests. Animals were sampled seven times over 2 years and were classified as positive if they had persistent agglutination titers or had Brucella isolated from specimens collected at completion of the study. Five of the original 32 study animals were lost to follow-up during the field trial. Six of the 14 (43%) vaccinated animals completing the study were classified as positive for Brucella infection—as were two of the 13 (15%) control animals (P=0.21). Isolates from four vaccinates and one control were confirmed as B. abortus biovar 1.     

固氮甘蔗新品种RB72-454引种及试验示范

引进固氮甘蔗新品种RB72-454,于2003~2005年在贞丰、望谟坝、坡地进行田间氮肥敏感性、不同用种量、吨糖田土配套技术研究试验示范。结果表明:RB72-454施用尿素20 kg/667m2比F134(CK)施用尿素40 kg/667m2增产41.5%,蔗糖分提高1.24%(绝对值),单位面积产糖量增加59.5%;每667m2用种量8 000芽比10 000芽增产7.5%,蔗糖分提高0.5个百分点,单位面积产糖量增加11.0%,节本增效336.4元/667m2;吨糖田土配套技术集成实施产糖量达1 066 kg/667m2,比F134增加47.9%;示范1 333.3 hm2,平均比F134增产37.7%,蔗糖分提高1.18个百分点,单位面积产糖量增加49.0%,增收810元/667m2,项目累计新增产值3 960万元,取得经济效益2 140.4万元。     

超级杂交稻苗头组合GD-1S/RB207高产示范小结

GD-1S/RB207是国家杂交水稻工程技术研究中心选育的超级杂交稻苗头新组合,2004年在湖南汝城小面积示范,单产13.16 t/hm2,2005年示范7.1 hm2,验收产量12.59 t/hm2。介绍了2005年的示范表现和主要栽培措施,分析了产量没有达到13.5t/hm2预期目标的原因,提出了该组合高产栽培示范应注意的技术措施。     

几种双孢蘑菇菌株对稻草降解能力的研究

以蘑菇属的5个菌株为试材,采用Bavendamm显色反应、RB亮蓝平板变色反应、Eriksson变色圈试验及木质降解试验等方法,研究双孢蘑菇对稻草的降解能力。结果表明:通过Bavendamm平板和RB亮蓝平板显色试验,初步判断2796及A5,优于其它菌种,有较高的木质素降解相关酶系(木质素降解酶;木质素过氧化物酶;锰依赖过氧化物酶)活力;这2种菌种进一步通过变色圈和降解试验,表明2796为选择性降解纤维素的菌种,而A5为选择性降解木质素的菌种,但2796对木质素的降解率为39.82%,A5仅为20.91%,说明菌种对木质素的选择性降解与否与其降解率之间没有相关性。