Exploring the role of copper and selenium in the maintenance of normal thyroid function among healthy Koreans

BackgroundSelenium and iodine are trace elements well known to have important roles in the synthesis and metabolism of thyroid hormones. However, the effects of other trace elements on thyroid hormones are still inconclusive. We investigated the association between several trace elements and thyroid hormones.MethodsThe data of 448 subjects who were measured for both, trace elements and TSH/free T4, at the Heath Checkup Center were retrospectively reviewed. The presence of thyroiditis (from thyroid echogenicity) and thyroid nodules were reviewed in the subjects who underwent thyroid ultrasonography.ResultsBlood concentrations of manganese, copper, selenium, and molybdenum were associated with TSH or free T4. After adjusting for age, sex, BMI, smoking, and alcohol consumption, blood copper levels were positively associated with free T4 in both sexes and selenium levels were positively associated with free T4 in women. There was no association between trace elements and thyroiditis. Blood copper concentration had a weak non-linear association with the presence of thyroid nodules.ConclusionsThis study demonstrated that blood concentrations of copper and selenium were significantly associated with free T4 in healthy Korean subjects with sufficient iodine intake suggesting their role in maintaining normal thyroid function.     

Functional divergence of two duplicated Fertilization Independent Endosperm genes in rice with respect to seed development

Fertilization Independent Endosperm (FIE) is an essential member of Polycomb Repressive Complex 2 (PRC2) that plays important roles in the developmental regulation of plants. OsFIE1 and OsFIE2 are two FIE homologs in the rice genome. Here, we showed that OsFIE1 probably duplicated from OsFIE2 after the origin of the tribe Oryzeae, but has a specific expression pattern and methylation landscape. During evolution, OsFIE1 underwent a less intensive purifying selection than did OsFIE2. The mutant osfie1 produced smaller seeds and displayed reduced dormancy, indicating that OsFIE1 predominantly functions in late seed development. Ectopic expression of OsFIE1, but not OsFIE2, was deleterious to vegetative growth in a dose‐dependent manner. The newly evolved N‐terminal tail of OsFIE1 was probably not the cause of the adverse effects on vegetative growth. The CRISPR/Cas9‐derived mutant osfie2 exhibited impaired cellularization of the endosperm, which suggested that OsFIE2 is indispensable for early seed development as a positive regulator of cellularization. Autonomous endosperm was observed in both OsFIE2^+? and osfie1/OsFIE2^+? but at a very low frequency. Although OsFIE1‐PRC2 exhibited H3K27me3 methyltransferase ability in plants, OsFIE1‐PRC2 is likely to be less important for development in rice than is OsFIE2‐PRC2. Our findings revealed the functional divergence of OsFIE1 and OsFIE2 and shed light on their distinct evolution following duplication.     

革兰氏阴性细菌外膜主要成分的跨膜转运机制研究进展

革兰氏阴性细菌的外膜由脂多糖、磷脂、外膜蛋白和脂蛋白等成分组成,是细菌抵御外界有害物质的首要物理屏障,与细菌致病性和耐药性密切相关.外膜各组分依赖特定的系统进行跨膜转运,包括脂多糖转运系统(lipopolysaccharide transport, Lpt)、脂质不对称维持系统(maintenance of lipid asymmetry, Mla)、β-桶状装配机器(β-barrel assembly machinery,Bam)以及脂蛋白定位系统(localization of lipoprotein,Lol).这些系统能够保证细菌外膜的完整与稳定,被视为维持细菌生命活动的"命门".因此,本文系统地综述革兰氏阴性细菌外膜主要成分的跨膜转运系统结构与功能,并对其未来研究方向进行展望,为新型靶向抗菌类药物研发提供新的思路.     

典型草原大针茅种群空间格局及对长期过度放牧的响应

种群空间格局是生态学研究的基本问题之一。典型草原带由于过度放牧退化严重, 原生群落罕见, 探讨原生群落的种群空间格局具有重要生态学意义。大针茅(Stipa grandis)草原是典型草原区广泛分布的主要群落类型, 1979年围封的大针茅样地, 是目前保存完整的大针茅草原原生群落。本文选择大针茅草原原生群落和长期过度放牧群落, 应用O-Ring函数结合不同零假设模型分析了大针茅种群的空间格局。结果表明: 在原生群落中大针茅种群在小尺度范围内呈均匀分布, 而在长期过度放牧群落中则表现为聚集分布。这说明在大针茅草原原生群落中竞争是主要的相互作用, 而在长期过度放牧群落中正相互作用居主导, 验证了胁迫梯度假说; 同时证明长期过度放牧改变了种群空间格局。     

地被植物对广东常绿阔叶林土壤养分的指示作用

为了解地被植物群落对土壤养分的响应和指示作用,利用指示种分析(ISA)法研究了广东常绿阔叶林地被植物与土壤养分的关系。结果表明,速效氮(AN)、速效磷(AP)、速效钾(AK)和有机质(OM)的综合作用对地被植物分布有显著影响(P0.05),且以速效磷有机质速效钾速效氮。地被植物的组成与分布在不同AP和OM梯度中均有显著差异(P 0.05),但在不同AK和AN梯度中差异不显著。土壤AN≤270 mg/kg的指示种是广东蛇葡萄(Ampelopsis cantoniensis)和油点草(Tricyrtis macropoda),270～360 mg/kg的指示种是狗骨柴(Tricalysia dubia);AP≤2 mg/kg的指示种是华山姜(Alpinia chinensis);AK≤100mg/kg的指示种是赤楠蒲桃(Syzygiumbuxifolium),AK为100～150mg/kg的指示种是十字苔草(Carexcruciate),AK150 mg/kg的指示种是金钗凤尾蕨(Pterisfauriei);OM 0.8%的指示种是箬竹(Indocalamustessellatus),OM≤0.6%的指示种是华山姜(Alpinia chinensis)和蔓胡颓子(Elaeagnus glabra),OM为0.6%～0.8%的指示种是豆腐柴(Premna microphlla)。利用有效的地被植物调查方式来监测森林的土壤状况为森林经营管理及土壤健康评价带来方便。地被植物指示种对土壤养分的响应不但能为研究地的立地条件提供理论支撑,还能为该物种的人工栽培提供理论依据,这对于生物多样性保育、生境恢复的引种栽培有重要意义。     

鹞落坪落叶阔叶林蔷薇科主要树种的空间分布格局及种间关联性

为探讨大别山森林群落的构建和演替机制, 本文基于安徽鹞落坪落叶阔叶林11.56 ha动态监测样地的定位监测资料, 采用最近邻分析和O-ring函数、Monte Carlo拟合和零模型选取的方法, 分析了落叶阔叶林蔷薇科主要树种水榆花楸(Sorbus alnifolia)、山樱花(Cerasus serrulata)和中华石楠(Photinia beauverdiana)不同年龄阶段的空间分布格局及种间关联性。结果表明: (1)在整个样地中3个树种的小树和成年树阶段都为聚集分布, 且随年龄增加聚集性减弱, 在老树阶段转为随机和均匀分布。(2)在0-50 m尺度范围内, 以完全随机模型(complete spatial randomness, CSR)为零假设时, 3个树种整体及小树都在小尺度(≤ 10 m)上呈聚集分布, 成年树与老树多为随机分布。以异质性泊松模型(heterogeneous Poisson, HP)为零假设时, 树种的聚集与生境异质性间呈负相关, 3个树种只在≤ 4 m尺度上出现聚集现象。(3) 3个树种种内各个年龄段之间在较大范围内多为负相关和无显著相关性, 同时各树种及不同年龄段之间受种间竞争和密度制约效应影响在小尺度上(≤ 10 m)多为负相关, 随尺度增加相关性减弱。综合而言, 大别山落叶阔叶林中蔷薇科植物的分布格局整体上多为聚集分布, 随树龄增加聚集性减弱, 在中大尺度上受生境异质性效应的影响显著, 在小尺度上多为负相关, 各树种内部各龄级相互之间也多为负相关。     

生境梯度影响下的天然红松种群空间格局与种内关联

为理清生境梯度下天然红松种群空间分布规律,以黑龙江省凉水国家级自然保护区内自坡底至坡顶的四种生境(生境Ⅰ,谷地平坡潮湿生境;生境Ⅱ,坡下缓坡潮湿生境;生境Ⅲ,坡上斜坡半湿润生境;生境Ⅳ,坡顶陡坡半干旱生境)类型中建群种红松种群为研究对象。分析不同林层(主林层、亚林层、演替层、更新层)红松种群的数量特征,并基于O-ring函数,在重复采样条件下评价了红松种群空间分布格局。结果表明:(1)下坡位生境(生境Ⅰ、Ⅱ)红松更新层种群数量显著大于上坡位(生境Ⅲ、Ⅳ)(P0.05),演替层中差异不显著;自坡底至坡顶的生境梯度上,主林层和亚林层中红松株数比例增加,红松种群年龄结构结构由倒J型向J型转变。(2)下坡位原始红松林更新层和演替层中红松种群聚集规模与聚集强度均高于上坡位,坡顶(生境Ⅳ)原始红松林更新层中红松种群聚集规模与聚集强度高于坡上(生境Ⅲ)。(3)四类生境的原始红松林中主林层与更新层中红松种群总体表现为空间独立,在个别尺度上表现出微弱的空间正关联或负关联;在0—5 m尺度上,下坡位红松林原始林内演替层与主林层红松种群表现为空间负关联,而上坡位生境林分对应林层间空间关系则为空间正关联;四类生境中,亚林层与主林层中红松种群在全部研究尺度上均表现为空间独立。可以认为,造成上坡位生境的原始红松林中幼树、幼苗聚集规模与强度弱于下坡位的原因是上坡位更新与演替层中种群数量较少;而随坡位上升,更现层、演替层与主林层中红松种群间的空间关系由空间负关联向空间正关联转变是生物与非生物因子共同作用的结果。研究结果为阔叶红松林的经营管理与生态修复提供了理论依据。     

微生态制剂联合莫西沙星序贯疗法对老年慢性阻塞性肺疾病合并下呼吸道感染患者肠道菌群及免疫功能的影响

目的探究微生态制剂联合莫西沙星序贯疗法对老年慢性阻塞性肺疾病(COPD)合并下呼吸道感染患者肠道菌群及免疫功能的影响。方法选取2016年2月到2019年2月我院收治的98例老年COPD合并下呼吸道感染患者为研究对象,按照随机数字表法分为观察组和对照组各49例。对照组患者采用莫西沙星序贯法进行治疗。观察组患者采用微生态制剂联合莫西沙星治疗。检测两组患者下呼吸道感染病原菌及肠道微生物变化,T淋巴细胞亚群(CD4⁺细胞,CD8⁺细胞,CD4⁺/CD8⁺)水平,并评价患者临床效果和并发症情况。结果治疗后两组患者CAT评分(8.23±3.64、10.41±4.08)和mMRC评分(1.35±0.82、1.77±0.61)均低于治疗前(23.01±4.47、22.87±5.26、2.79±0.54、3.04±0.74),且观察组下降幅度大于对照组,差异具有统计学意义(均P<0.05)。治疗后两组患者下呼吸道感染主要病原菌中肺炎克雷伯菌、大肠埃希菌、铜绿假单胞菌、肺炎链球菌检出率均低于治疗前,但组间比较差异无统计学意义(均P>0.05)。治疗后两组患者肠道双歧杆菌、嗜酸乳杆菌、粪肠球菌数量均高于治疗前,大肠埃希菌数量均低于治疗前,且观察组改善情况优于对照组,差异有统计学意义(均P<0.05)。治疗后两组患者CD4⁺细胞、CD4⁺/CD8⁺均高于治疗前,且观察组高于对照组,差异有统计学意义(均P<0.05)。CD8⁺细胞数量治疗前后及组间比较差异无统计学意义(均P>0.05)。治疗后观察组患者腹胀(18.4%)、胃潴留(20.4%)发生率均低于对照组(36.7%、38.8%),差异有统计学意义(均P<0.05)。两组患者应激性溃疡发生率(20.4%、24.5%)差异无统计学意义(P>0.05)。结论微生态制剂联合莫西沙星序贯疗法治疗老年COPD合并下呼吸道感染能促进患者肠道微生态平衡,调节免疫功能,进而改善患者病情。     

A model for gain of function in superoxide dismutase

Studies have found that mutant, misfolded superoxide dismutase [Cu–Zn] (SOD1) can convert wild type SOD1 (wtSOD1) in a prion-like fashion, and that misfolded wtSOD1 can be propagated by release and uptake of protein aggregates. In developing a prion-like mechanism for this propagation of SOD1 misfolding we have previously shown how enervation of the SOD1 electrostatic loop (ESL), caused by the formation of transient non-obligate SOD1 oligomers, can lead to an experimentally observed gain of interaction (GOI) that results in the formation of SOD1 amyloid-like filaments. It has also been shown that freedom of ESL motion is essential to catalytic function. This work investigates the possibility that restricting ESL mobility might not only compromise superoxide catalytic activity but also serve to promote the peroxidase activity of SOD1, thus implicating the formation of SOD1 oligomers in both protein misfolding and in protein oxidation.