Genetic variation in PLAG1 is associated with early fertility in Australian Brahman cattle

Variation in the genome region coding for PLAG1 has well-documented associations with skeletal growth and age at puberty in cattle. However, the influence of PLAG1 on other economically important traits such as cow stayability has not yet been explored. Here we investigate the effect of PLAG1 variation on early and later in life female fertility, as well as size and growth, in a well-phenotyped Australian Brahman herd. Yearly pregnancy and productivity records were collected from 2,839 genotyped Brahman cows and used to generate fertility, growth, and weight phenotypes. A variant on chromosome 14 in PLAG1 ({"type":"entrez-nucleotide","attrs":{"text":"NC_037341.1","term_id":"1378962600","term_text":"NC_037341.1"}}NC_037341.1:g.23338890G>T, rs109815800) was previously determined to be a putative causative mutation associated with variation in cattle stature. The imputed PLAG1 genotype at this variant was isolated for each animal and the effect of PLAG1 genotype on each trait was estimated using linear modeling. Regardless of how heifer fertility was measured, there was a significant (P < 0.05) and desirable relationship between the additive effects of PLAG1 genotype and successful heifer fertility. Heifers with two copies of the alternate allele (TT) conceived earlier and had higher pregnancy and calving rates. However, the effects of PLAG1 genotype on fertility began to diminish as cows aged and did not significantly influence stayability at later ages. While there was no effect of genotype on growth, PLAG1 had a negative effect on mature cow weight (P < 0.01), where females with two copies of the alternate allele (TT) were significantly smaller than those with either one or none. Selection emphasis on improved Brahman heifer fertility will likely increase the frequency of the T allele of rs109815800, which may also increase herd profitability and long-term sustainability through improved reproductive efficiency and reduced mature cow size.     

1990—2020年于桥水库流域景观格局时空演变及驱动力

景观格局时空演变是土地利用变化最直观的表现形式,剖析流域景观格局变化及其驱动力,对流域土地利用管理及水质保护具有重要意义。以于桥水库流域1990、2000、2010年和2020年4期土地利用数据为基础,采用半变异函数法和移动窗口法分析土地利用时空变化及其景观破碎度、斑块形状和多样性变化,并使用灰色关联法分析变化的驱动因素。结果表明,1990—2020年,于桥水库流域内城镇建设用地、农村居民点和林地的面积分别增加了588.89%、24.19%和0.83%,耕地、草地和水域面积分别减少了15.14%、5.96%和3.13%。1990—2010年,城镇建设用地大幅增长,耕地、草地等大幅减少。2010—2020年,城镇建设用地的增长速率放缓,林地开始增加。30年间,整体景观水平上,流域景观破碎度和多样性增加,景观斑块形状趋于复杂化。类别水平上,耕地及草地破碎化,景观斑块形状更加复杂。城镇建设用地斑块密度指数（PD）和最大斑块指数（LPI）增加,平均斑块面积指数（MPS）大幅下降。于桥水库周边和遵化市城区是流域景观格局变化的两个中心。流域内景观格局变化与人口密度、农村人口数、规模以上工业企业数及...     

Trikoramides B–D,Bioactive Cyanobactins from the Marine Cyanobacterium Symploca hydnoides

Three new cyanobactins, trikoramides B (1)–D (3), have been isolated from the marine cyanobacterium, Symploca hydnoides, following a preliminary bioassay-guided isolation of the two most active polar fractions based on the brine shrimp toxicity assay. These new cyanobactins are new analogues of the previously reported cytotoxic trikoramide A (4) with differences mainly in the C-prenylated cyclotryptophan unit. Their planar structures were elucidated from their 1D and 2D NMR spectral data in combination with the HRMS/MS data. Marfey’s method, 2D NOESY NMR spectroscopic and ECD spectra analyses were used to determine the absolute stereochemistry of trikoramides B (1)–D (3). Trikoramides B (1) and D (3) exhibited cytotoxicity against MOLT-4 acute lymphoblastic leukemia cell line with IC₅₀ values of 5.2 µM and 4.7 µM, respectively. Compounds 1 and 3 were also evaluated for their quorum-sensing inhibitory assay based on the Pseudomonas aeruginosa PAO1 lasB-gfp and rhlA-gfp bioreporter strains. Although trikoramide B (1) exhibited weak quorum-sensing inhibitory activity, the Br-containing trikoramide D (3) exhibited moderate to significant dose-dependent quorum-sensing inhibitory activities against PAO1 lasB-gpf and rhlA-gfp bioreporter strains with IC₅₀ values of 19.6 µM and 7.3 µM, respectively.     

凡纳滨对虾和罗氏沼虾肠道微生物及抗生素抗性基因多样性分析

探究凡纳滨对虾和罗氏沼虾肠道微生物及抗生素抗性基因(antibiotic resistance genes, ARGs)种类的差异。通过高通量测序和变性梯度凝胶电泳(denaturing gradient gel electrophoresis, DGGE)技术分析2种虾肠道微生物群落结构差异和微生物多样性,并运用PCR方法检测了2种虾肠道细菌常见38种ARGs的携带情况。结果显示,获得凡纳滨对虾和罗氏沼虾肠道细菌有效序列分别为42 795和40 713条,物种注释单元(operational taxonomic unit, OTU)数目分别为124和82,分类地位明确的细菌种类分别隶属5个门、17个属和5个门、16个属。凡纳滨对虾肠道细菌的优势类群为变形菌门,所占比例为75.45%,优势菌属为副球菌属(25.83%)和不动杆菌属(25.24%);罗氏沼虾肠道细菌的优势类群是厚壁菌门(49.74%),优势菌属为乳球菌属(49.01%)和弧菌属(29.98%)。凡纳滨对虾肠道细菌(2.19)Shannon指数高于罗氏沼虾肠道细菌(1.78),表明前者肠道细菌多样性大于后者。DGGE图谱的分析结果与高通量测序一致,2种虾肠道细菌种类差异很大。PCR结果显示,凡纳滨对虾肠道细菌携带15种ARGs,罗氏沼虾肠道细菌携带14种ARGs。本实验表明凡纳滨对虾肠道细菌的群落种类多样性、OTU丰富度、物种总数和ARGs种类均高于罗氏沼虾肠道细菌,为后续肠道微生物资源的挖掘提供了理论依据。     

Cultivar mixture effects on disease and yield remain despite diversity in wheat height and earliness

Cultivar mixtures can stabilize yield and reduce pathogen spread in plant populations. A field experiment was performed to determine (a) whether a large difference between the cultivars in the mixture (e.g., plant height or earliness) would have an impact on mixture performance, and (b) whether such differences would modify the classical rules for mixture design. Mixtures were constituted from wheat cultivars with diversity for many traits, including plant height, flowering date, disease resistance, and yield potential. The field experiment was conducted over 3 years, testing each year 72–90 mixtures of two, four, or eight cultivars, and their corresponding pure stands. Disease severity and yield of cultivar mixtures were strongly related to the mean values of the component cultivars in pure stands. Despite the considerable diversity of the mixtures tested, the classic rules (e.g., proportion of susceptible cultivars) already tested in mixtures with similar height and earliness were effective for decreasing disease severity. Agronomic heterogeneity for traits such as plant height, yield potential, or earliness of the cultivars in mixtures did not have a negative impact on disease severity and yield relative to pure stands. Increasing the number of cultivars in the mixture from two to eight had no impact on the mean disease severity and yield of the mixtures, but reduced the variability of disease severity and yield in the mixture relative to pure stands. These results suggest that it may be possible to increase within-field wheat diversity by combining more contrasting cultivars in mixtures than was previously thought.     

Emergence de Ceratitis capitata (Diptera: Tephritidae) sur culture protégée de piment (Solanaceae) en zone subsaharienne (Algérie)

In Algeria, the Mediterranean fruit fly has long been associated with fruit production in coastal regions with a temperate climate. But with climate change, especially in autumn and spring, this fly has spread and attacks other host plants. The medfly appeared in the sub-Saharan area of Souf region (Algeria) on chilli pepper (Capsicum annuum) under protected crops and causes significant damage.     

First report of Zaprionus indianus and Z. tuberculatus (Diptera: Drosophilidae) in Tunisia

In October 2019, unusual damage was observed on Carissa macrocarpa (Apocynaceae) fruit at the ornamental nursery of the Higher Agronomic Institute (ISA CM), Chott Mariem (Sousse, Tunisia). Samples of fruit were collected and brought to the laboratory for observation and rearing. After a few days, adult flies emerged from infested fruit. Zaprionus indianus Gupta, Z. tuberculatus Malloch (Diptera Drosophilidae) and Ceratitis capitata Wiedemann (Diptera, Tephritidae) were identified morphologically. Information on the morphology, distribution and ecology of the two Zaprionus species are provided. This is the first record of Z. indianus and Z. tuberculatus in Tunisia.     

Screening for durum wheat (Triticum durum Desf.) cultivar resistance to drought stress using an integrated physiological approach

Journal of Crop Science and Biotechnology - Drought is one of the major abiotic stresses with a detrimental impact on plant growth and development irrespective of the developmental stage. Thus,...     

青海班玛地区藏族药用民族植物学研究

对青海班玛地区藏族药用民族植物学进行了调查。结果表明,班玛地区藏族药用植物有478种,隶属于70科228属,藏族在选择药用植物种类、药用部位、采收季节、加工炮制、饮用方法等方面具有独特性。为该地区的药用植物资源的保护和可持续利用,提出了相应的建议。     

玉米光合特性和冠层微环境对密度和行株距配置的响应

适宜密度及行株距配置可构建合理的玉米群体和冠层结构,提高光合效率,系统分析玉米光合特性及冠层微环境对密度和行株距配置的响应机制,为华北平原玉米光温高效生产提供科学依据。试验采用裂区设计,主区设密度6.75万株/hm ²（D1）和8.25万株/hm ²（D2）,副区为3种行株距配置:60cm等行距（H1）、宽窄行80cm+40cm（H2）、匀播（H3）38cm（行株距相同,D1）和34.5cm（行株距相同,D2）。结果表明:常规生产密度等行距（D1H1）种植和高密度宽窄行（D2H2）种植能形成合理的群体冠层结构,具有适宜的冠层温度、CO₂浓度和相对湿度,能促进植株对光能的吸收和利用,提高净光合速率,从而获得较高的产量。因此,在常规密度等行距种植基础上,进一步增加密度至8.25万株/hm ²时,宽窄行种植方式具有较高的产量潜力。