Best linear unbiased prediction of host-range of the facultative parasite Colletotrichum gloeosporioides f. sp. salsolae, a potential biological control agent of Russian thistle

Russian thistle or tumbleweed (Salsola tragus L.) is an introduced invasive weed in N. America. It is widely distributed in the US and is a target of biological control efforts.The fungus Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. in Penz. f. sp. salsolae (CGS) is a facultative parasite under evaluation for classical biological control of this weed. Host-range tests were conducted with CGS in quarantine to determine whether the fungus is safe to release in N. America. Ninetytwo accessions were analyzed from 19 families: Aizoaceae, Alliaceae, Amaranthaceae, Apiaceae, Asteraceae, Brassicaceae, Cactaceae, Campanulaceae, Chenopodiaceae, Cucurbitaceae, Cupressaceae, Fabaceae, Malvaceae, Nyctaginaceae, Phytolaccaceae, Poaceae, Polygonaceae, Sarcobataceae, and Solanaceae and 10 tribes within the Chenopodiaceae: Atripliceae, Beteae, Camphorosmeae, Chenopodieae, Corispermeae, Halopepideae, Polycnemeae, Salicornieae, Salsoleae, and Suaedeae. These included 62 genera and 120 species. To facilitate interpretation of results, disease reaction data were combined with a relationship matrix derived from internal transcribed spacer DNA sequences and analyzed with mixed model equations to produce Best Linear Unbiased Predictors (BLUPs) for each species. Twenty-nine species (30 accessions) from seven closely-related Chenopodiaceae tribes had significant levels of disease severity as indicated by BLUPs, compared to six species determined to be susceptible with least squares means estimates. The 29 susceptible species were: 1 from Atripliceae, 4 from Camphorosmeae, 1 from Halopepideae, 2 from Polycnemeae, 6 from Salicornieae, 8 from Salsolae, and 7 from Suaedeae. Most species in the genus Salsola, which are all introduced and weedy, were very susceptible and damaged by CGS. Statistical comparisons and contrasts of BLUPs indicated that these Salsola species were significantly more susceptible than non-target species, including 15 species from relatives in the closely-related genera Bassia (=Kochia), Nitrophila, Salicornia, Sarcocornia, and Suaeda. Of the 29 susceptible species, 10 native or commercially important species in N. America were identified as needing additional tests to determine the extent of any damage caused by infection.     

吸烟对健康人群唾液微生物组的影响

【背景】吸烟是重要的公共健康问题,可能通过改变唾液微生物组影响口腔健康甚至全身健康。【目的】探究吸烟对中国健康人群唾液微生物组的影响,为研究吸烟在疾病发展中的作用提供线索。【方法】收集167位健康个体的唾液样本,利用HiSeq高通量测序技术对样品中16S rRNA基因V3-V4区进行测序,分析比较吸烟者和非吸烟者的唾液微生物组的多样性、群落结构和物种丰度,并预测功能组成,探究吸烟对唾液微生物组的影响。【结果】吸烟对唾液微生物组的α多样性影响较小,但是在微生物组组成上,吸烟组中奈瑟菌属、艾肯菌属、二氧化碳嗜纤维属等细菌明显减少,而普雷沃氏菌属、韦荣氏球菌属、放线菌属、奇异菌属和巨球型菌属等细菌明显增加。在功能上,PICRUSt的预测结果显示吸烟组富集不依赖氧气的代谢功能,非吸烟组富集需要氧气参与的代谢功能。【结论】吸烟可能会通过改变唾液微生物组,造成微生物组功能途径的变化,进而引发与吸烟相关的疾病。     

Reliability and time-of-day effect on measures of change of direction deficit in young healthy physical education students

ABSTRACT

This study aimed to examine the reliability and the time-of-day effect of the 505 change of direction (CoD), 10-m sprint, and change of direction deficit test (CoDD). At two different time of days, 39 young diurnally active physical education male students performed different physical tests: 505 CoD, and sprint tests. Measurements were taken at two separate testing sessions, i.e. in the morning (07:00–08:30 h) and early evening (17:00–18:30 h) in a randomized and counter-balanced setting on nonconsecutive days in 21 of them (21.5 ± 1.5 y of age). The results showed that the 505 CoD test, 10-m sprint, and CoDD performances were a reliable test, and performances were better in the evening the 505 CoD, 10-m sprint, and CoDD testing provided reliable and sensitive scores. In addition, phase 2 showed that CoD, speed, and CoDD are affected by the time of day.     

基于不同可加性方法的黑龙江省红松人工林林分生物量模型

大尺度估算森林生物量一直是人们关注的焦点,而构建林分水平的生物量模型是一种估算森林乔木层生物量的方法。本研究基于聚合法1、聚合法2、平差法、分解法构建红松人工林林分生物量模型,并对比分析4种可加性方法的预测精度,为黑龙江省红松人工林的生物量预测提供科学依据。各模型均使用权函数来消除各模型的异方差,并以留一交叉验证法(LOOCV)作为各模型的检验方法。结果表明: 平差法的整体预测能力略优于聚合法1、聚合法2和分解法,预测精度排序为平差法>聚合法1>聚合法2>分解法;分别对比不同林分断面积的预测能力时,4种可加性方法的预测精度不一致。当红松人工林的林分断面积分布于0～10或50～60 m²·hm^-2区间时,建议采用分解法的参数估计值,而林分断面积分布于其他区间时,建议采用平差法的参数估计值。     

Design-based mapping of tree attributes by 3P sampling

The estimation of individual values (marks) in a finite population of units (e.g., trees) scattered onto a survey region is considered under 3P sampling. For each unit, the mark is estimated by means of an inverse distance weighting interpolator. Conditions ensuring the design-based consistency of maps are considered under 3P sampling. A computationally simple mean squared error estimator is adopted. Because 3P sampling involves the prediction of marks for each unit in the population, prediction errors rather than marks can be interpolated. Then, marks are estimated by the predictions plus the interpolated errors. If predictions are good, prediction errors are more smoothed than raw marks so that the procedure is likely to better meet consistency requirements. The purpose of this paper is to provide theoretical and empirical evidence on the effectiveness of the interpolation based on prediction errors to prove that the proposed strategy is a tool of general validity for mapping forest stands.     

Consequences of Interspecific Competition on the Virulence and Genetic Composition of a Nucleopolyhedrovirus in Spodoptera frugiperda Larvae Parasitized by Chelonus insularis

Nucleopolyhedroviruses ( Baculoviridae ) are virulent insect pathogens that generally show a high degree of host specificity and have recognized potential as biological insecticides. Whenever viruses are applied for pest control, a proportion of the infected insects will also be parasitized by hymenopteran or dipteran parasitoids and interspecific competition for host resources will occur; the severity of such competition is likely to be modulated to a large degree by the virulence of each type of parasite. We examined the impact of parasitism by the solitary egg-larval endoparasitoid Chelonus insularis (Hymenoptera: Braconidae) on the speed of kill of nucleopolyhedrovirus-infected Spodoptera frugiperda (Lepidoptera: Noctuidae) larvae and the pattern of host growth and virus production in infected and/or parasitized hosts. We also examined the effect of parasitism on the virulence, infectivity and genetic composition of serially passaged virus. Both parasitism and viral infection resulted in a marked reduction in host growth. When third instar larvae were dually parasitized and virus-infected, the growth rate was even more severely affected compared to parasitized larvae. There was a significant increase in virus production in larvae infected at later instars. Interspecific competition resulted in a substantial decrease in pathogen production in parasitized larvae infected at the fourth instar, but not in parasitized larvae infected at earlier instars. The serial passage experiment resulted in the appearance of four distinct genetic isolates of the virus detected by restriction endonuclease analysis. Of the three isolates that appeared in nonparasitized larvae, two showed increased virulence, expressed by mean time to death, and for one of these the infectivity, expressed as LC 50 , was reduced. One isolate that appeared in parasitized larvae (isolate D) had increased virulence and infectivity. Southern blot analysis indicated that virus isolate D was most likely generated by point mutation of a restriction site or by alterations such as duplications, deletions or by recombination of two or more genotypic variants present in the wild-type nucleopolyhedrovirus isolate. Our study provides clear evidence of interspecific competition within the host, since, depending on the timing of inoculation, adverse effects were observed upon both the parasitoid and the virus.     

Projection maps of three members of the KdgM outer membrane protein family

We present the projection structures of the three outer membrane porins KdgM and KdgN from Erwinia chrysanthemi and NanC from Escherichia coli, based on 2D electron crystallography. A wide screening of 2D crystallization conditions yielded tubular crystals of a suitable size and quality to perform high-resolution electron microscopy. Data processing of untilted samples allowed us to separate the information of the two crystalline layers and resulted in projection maps to a resolution of up to 7 Å. All three proteins exhibit a similar putative β-barrel structure and the three crystal forms have the same symmetry. However, there are differences in the packing arrangements of the monomers as well as the densities of the projections. To interpret these projections, secondary structure prediction was performed using β-barrel specific prediction algorithms. The predicted transmembrane β-barrels have a high similarity in the arrangement of the putative β-strands and the loops, but do not match those of OmpG, a related protein porin whose structure was solved.