Detection of Novel Reassortant Influenza A (H3N2) and H1N1 2009 Pandemic Viruses in Swine in Hanoi,Vietnam

From May to September 2013, monthly samples were collected from swine in a Vietnamese slaughterhouse for influenza virus isolation and serological testing. A(H1N1)pdm09 viruses and a novel H3N2 originating from reassortment between A(H1N1)pdm09 and novel viruses of the North American triple reassortant lineage were isolated. Serological results showed low seroprevalence for the novel H3N2 virus and higher seroprevalence for A(H1N1)pdm09 viruses. In addition, serology suggested that other swine influenza viruses are also circulating in Vietnamese swine.     

木毒蛾核多角体病毒（LxNPV）杀虫剂：Ⅱ.制剂的研制

通过室人工饲毒养虫并结合林间防治木毒蛾，回收病死虫尸，获取毒源，添加各种辅助剂，配制成９０１－１可湿性粉剂和９０１－２乳剂，进行林间大面积防治木毒蛾试验，１０天防治效果达８０％以上。实验表明，丙酮－乳糖共沉法回木毒蛾核多角体病毒，回收率可达８０．１７％。     

基于语义分割与实例分割的玉米茎秆截面参数测量方法

茎秆微观结构与其力学性能密切相关,影响作物的抗倒伏性能。但作物茎秆微观表型参数难以通过人工方式获取,因此急需自动化的测量方法。本研究以玉米为材料,通过光学显微镜获得玉米茎秆横截面切片图像,基于深度学习架构融合ResNet和Unet构建语义分割Res-Unet网络模型,对截面表皮、周皮和髓区3个功能区域进行分割;针对维管束数量多、面积小、密度大的特点,以EfficientDet作为基础网络架构,根据维管束尺寸小的特性,减少双向特征图金字塔(BiFPN)的层数,达到提高推理速度、减少显存占用量的目的,同时添加掩膜分割分支,构造新的网络Eiff-BiFPN实现对维管束的分割。实验结果表明,功能区域分割的平均DICE达到88.17%;维管束分割的AP₅₀和AP_50:70分别达到88.78%和72.80%。根据分割结果,可以获得玉米茎秆截面尺寸、各功能区域尺寸和维管束数量、面积等微观结构参数。本文方法具有精确性、实时性和可用性,可用于玉米茎秆微观结构参数的自动化测定,为作物抗倒伏研究提供技术基础。     

蓖麻植株力学特性试验研究

为研究蓖麻力学条件,对蓖麻的果—柄接点、茎—柄接点和茎秆不同生长部位的抗拉特性、抗弯特性进行力学测试。结果表明：成熟期果—柄抗拉力和抗拉强度分别为3.31～6.74 N、3.48～8.31 MPa,收获期果—柄抗拉力和抗拉强度分别为1.90～4.15 N、2.42～5.28 MPa;茎—柄抗拉力和抗拉强度分别为15.78～37.07 N、19.70～3466 MPa;茎秆的抗拉力、弹性模量和抗拉强度分别为56.99～130.42 N、160.99～203.80 MPa、2850～65.21 MPa,茎秆的抗弯力、弯曲截面模量和抗弯强度分别为15.20～91.04 N、31.53～173.07 MPa、19.27～21.04 MPa。分析试验结果可知,果—柄连结强度与茎—柄连结强度、茎秆抗拉强度及抗弯强度之间存在显著性差异,证明在采摘过程中蓖麻果—柄接点更易分离,其次是茎—柄接点,通过合理设计采摘部件工作参数,可以实现只采收蓖麻蒴果,而较少破坏茎秆。     

青蒿中番茄斑萎病毒和烟草花叶病毒的分子鉴定及相关序列分析

番茄斑萎病毒(tomato spotted wilt virus, TSWV)和烟草花叶病毒(tobacco mosaic virus, TMV)是2种重要的植物病原病毒, 对多种经济作物的产量和品质均造成严重影响。2021年-2022年, 在云南省丽江市烟草种植区不同烟区采集叶片黄化、皱缩以及无症状的青蒿Artemisia caruifolia样品共计14份, 利用免疫金标速测卡和RT-PCR对其病原病毒进行检测。利用免疫金标速测卡检测结果显示, 在所检样品中有9份样品检测出TSWV, 检出率为64.28%, 有3份样品检测出TMV, 检出率为21.43%, 2种病毒复合侵染的检出率同样为21.43%;利用RT-PCR对复合侵染的3份样品进行分子检测, 结果显示, 在3份复合侵染青蒿样品中获得3条TSWV N基因序列、3条TMV cp基因序列和2条TMV RdRp部分序列。TSWV青蒿分离物与分离自云南的TSWV-2分离物相似性最高, 为99.6%;TMV青蒿分离物与分离自辽宁的TMV-Shenyang分离物和分离自云南的TMV-Yongren-1相似性最高, 均大于99.4%。这是首次发现TSWV和TMV 2种不同属病毒复合侵染青蒿。     

Localization of putative pituitary stem/progenitor cells in female dairy cattle

Research on sex-determining region Y-box 2 (SOX2)-positive pituitary stem/progenitor cells, as a source of hormone-producing cells, is progressing rapidly in rodents. However, the stem/progenitor cells supplying hormone-producing cells that are essential for growth, reproduction, and lactation in bovines have not yet been identified. In this study, we characterized SOX2-positive cells in the pituitary gland of dairy cattle (Holstein heifers) after sexual maturity. Immunofluorescence analysis revealed that the localization pattern of SOX2-positive cells in the dairy cattle pituitary gland was similar to that observed in the rodent pituitary gland; the marginal cell layer (MCL), dense cell clusters, and single cells scattered in the parenchyma of the anterior lobe. Furthermore, most of the SOX2-positive cells were positive for the pituitary stem/progenitor cell niche markers E-cadherin and cytokeratin 8+18, which have been reported in rodents. In addition, in the MCL of the anterior lobe, there was a subpopulation of SOX2-positive cells positive for paired-related homeobox 1 and 2, whereas negative for S100β. Moreover, in the parenchyma of the anterior lobe, co-localization of SOX2 and pituitary hormones was infrequent. In summary, this study reveals the localization of putative pituitary stem/progenitor cells positive for SOX2 in dairy cattle. These results provide valuable information to support further investigation of cell supply in the dairy cattle pituitary gland.     

Public safety aspects of pyrethroid insecticides used in West Nile virus-carrying mosquito control

West Nile virus is becoming increasingly prevalent in the USA, causing fever, encephalitis, meningitis and many fatalities. Spread of the disease is reduced by controlling the mosquito vectors by a variety of means, including the use of pyrethroid insecticides, which are currently under scrutiny for potential carcinogenic effects in humans. Pyrethrins and resmethrin, a pyrethroid, have been shown to cause tumours in rat and mouse models respectively. However, the tumours appear to be caused by liver enzyme induction and hypertrophy rather than genotoxicity, and the results are therefore unlikely to be applicable to humans. Nonetheless, for resmethrin, the US Environmental Protection Agency (EPA) has concluded that there is a likely risk of carcinogenicity in humans, requiring the manufacturers to provide more detailed data to prove that it can be used safely in vector control. Reproductive toxicity of resmethrin in the rat is also discussed.     

West Nile virus in North America: perspectives on epidemiology and intervention

West Nile virus (WNV) invaded New York in 1999 and rapidly swept across the North American continent to the West Coast, north into southern Canada and south into Latin America, with minimal genetic change. Regional epidemics in equines and humans typically have included a year of viral introduction with minimal activity, successful overwintering, explosive amplification to epidemic levels the following year and then rapid subsidence. Overwintering possibly included long-term mosquito or avian infections, continued low-level transmission at southern latitudes and dispersal by south-north migrants. Explosive amplification has been associated with infections in several corvid species and other urban birds that produce elevated viremias capable of efficiently infecting even moderately susceptible mosquito species. Intervention has included mass vaccination of equines, and proactive and reactive mosquito control. Proactive mosquito control in areas with established infrastructure has been successful in reducing case incidence.     

After nasopharyngeal infection,foot-and-mouth disease virus serotype A RNA is shed in bovine milk without associated mastitis

Foot-and-mouth disease (FMD) is a highly contagious aphthoviral infection of cloven-hoofed animals, inducing vesiculopustular stomatitis, pododermatitis, and thelitis. Vesicular fluid represents a major pathway of virus excretion, but bovine milk is another important source of virus shedding. We describe here the time course of FMD virus (FMDV) excretion in the milk and characterize associated lesions in the mammary gland. Three dairy cows were infected by nasopharyngeal instillation of FMDV and monitored over 12 d. Autopsy was performed at the end of the study, and specimens were collected for histopathology, IHC, and RT-qPCR. All 3 cows developed fever, drooling, vesiculopustular stomatitis, interdigital dermatitis, and thelitis. FMDV RNA was detectable in whole milk until the end of the trial, but only transiently in saliva, nasal secretions, and blood serum. Although histology confirmed vesiculopustular lesions in the oral and epidermal specimens, the mammary glands did not have unequivocal evidence of FMDV-induced inflammation. FMDV antigen was detectable in skin and oral mucosa, but not in the mammary gland, and FMDV RNA was detectable in 9 of 29 samples of squamous epithelia but only in 1 of 12 samples of mammary gland.     

一起猪流行性腹泻病毒与博卡病毒混合感染病例分析

陕西渭南某猪场发生了一起仔猪腹泻病例,通过临床症状观察、病理解剖、细菌分离以及病原RT-PCR检测,确诊为一起流行性腹泻病毒混感博卡病毒病例。针对发病原因提出了防治措施,为防控仔猪腹泻提供参考。