Iodine Nutrition and Thyroid Function in Pregnant Women Exposed to Different Iodine Sources

Determination of the public health concern about magnesium (Mg) in health and disease has been confounded by the lack of a practical measure of status. This has resulted in a lack of consistency in associating Mg deficiency with specific pathological conditions. Some attempts at associating Mg with a chronic disease have used the Dietary Reference Intakes (DRIs) as a status assessment measure. Use of current DRIs for Mg is problematic because recent evidence suggests that they should be updated and based on body weight. An evidence-based suggested Estimated Average Requirement (EAR) and Recommended Dietary Allowance (RDA) for a 70-kg individual is 175 and 250 mg/day, respectively. However, numerous dietary and physiological factors can affect the need for Mg and thus affect the use of the current or suggested new DRIs to assess Mg status. Calcium intakes above normal requirements can decrease Mg balance and exacerbate signs of Mg deficiency. Mg deficiency apparently occurs often in obesity because of increased need to counteract the inflammatory stress induced by adipose tissue dysfunction. Deficiency in anti-oxidant nutrients such as vitamin E and selenium can exacerbate a response to low dietary Mg indicated by increased oxidative stress which can lead to chronic disease. Dietary modifiers of Mg absorption and excretion affect balance and thus the need for Mg. Factors decreasing Mg balance include low dietary protein and non-fermentable fiber, while factors that can increase balance include fructose and fermentable fiber and fructose-containing oligosaccharides. Use of the DRIs to assess the Mg status of a population or group needs to consider their physiological characteristics and dietary habits and be aware that the DRIs may need updating. The DRIs only can be considered a component of a toolbox that presently includes serum Mg concentration and the daily urinary Mg excretion to assess the Mg status of an individual.

     

醋酸钙不动杆菌对盐碱胁迫下达乌里胡枝子促生效应研究

达乌里胡枝子(Lespedezadavurica)是黄土高原地区重要的生态修复草种,但土壤盐碱化极大影响了达乌里胡枝子的生长,制约了其经济和生态价值。接种根际促生菌剂是提高植物对盐碱胁迫抗性的重要途径。【目的】验证醋酸钙不动杆菌(Acinetobacter calcoaceticus)对盐碱胁迫下达乌里胡枝子幼苗和成株的促生效应,初步揭示其促进豆科植物生长的潜在机理,为田间应用提供理论依据。【方法】采用解钾培养基对2株达乌里胡枝子根际分离的醋酸钙不动杆菌的解钾能力进行测定;采用液体发酵法对菌株分泌铁载体、吲哚乙酸(indole-3-acetic acid, IAA)的能力进行定量测定;分别在培养皿和盆栽条件下,验证菌株的促生能力及其机制。【结果】菌株DP25和DP27具有解钾和分泌铁载体、IAA的能力,其中相对铁载体表达量值(siderophore, SU)分别为53.13%和86.67%,IAA含量分别为1.01 mg/L和17.31 mg/L;菌株DP25显著提高了培养皿中达乌里胡枝子幼苗的茎长和根长;菌株DP25和DP27对盐碱胁迫下达乌里胡枝子成株的光合色素合成及其光合作用产生...     

可用于二氧化碳捕获过程的微生物碳酸酐酶的挖掘与改造

二氧化碳排放量的急剧上升引起全球温室效应加剧。碳酸酐酶是地球上反应速率最快的几种酶之一,可以大幅提高CO_2捕获和生物矿化的效率,从而降低大气中CO_2的排放量。但捕获过程在高温条件,而CO_2生物矿化形成CaCO_3的过程则需要碱性条件。因此,迫切需要筛选出既嗜热又耐碱的碳酸酐酶以用于CO_2捕获,极端微生物是这类酶的重要来源之一。文中系统、深入地介绍了目前从极端微生物或利用蛋白质工程技术获取嗜热、耐碱的碳酸酐酶的最新研究进展,同时简要介绍了一些新型固定化碳酸酐酶的方法。最后指出当前研究的重点应致力于拓宽寻找碳酸酐酶的范围,改良蛋白质工程改造技术,研发高效廉价、易于放大的固定化方法,为减轻温室效应、延缓全球变暖这一迫切需要解决的问题提供新思路。     

A Comparison of the Effects of Estrogen and Cimicifuga racemosa on the Lacrimal Gland and Submandibular Gland in Ovariectomized Rats

This study aims to observe the effects of estradiol and Cimicifuga racemosa on the lacrimal gland and submandibular gland of ovariectomized rats. We randomly divided 20 adult female SD rats into four groups—a sham-operated group (SHAM), ovariectomized (OVX) group, ovariectomized group treated with estradiol (OVX+ E), and ovariectomized group treated with the isopropanolic extract of Cimicifuga racemosa (OVX+ iCR). The SHAM group and OVX group used distilled water to instead the drugs. Two weeks after ovariectomy, the estradiol and iCR were administered for 4 weeks. Next, we used H&E staining and electron microscopy to observe any histological changes in the lacrimal and submandibular glands and immunohistochemical staining to observe the expressions of cleaved caspase-3 (Casp-3) and Cu-Zn SOD (superoxide dismutase). The H&E staining find that both drugs can prevent the cells of area from shrinkage in the two kinds of gland. But under the electron microscopy, estradiol and iCR have different efficacy. Estradiol is more effective at protecting mitochondria in lacrimal gland acinar cells than iCR, and iCR is more effective at suppressing endoplasmic reticulum expansion than estradiol. Both estradiol and iCR have a similar protective function on mitochondria in the submandibular gland. The protective function of the two glands may inhibit apoptosis by suppressing the expression of Casp-3. In addition, iCR increases the expression of Cu-Zn SOD in duct system of submandibular gland. The results suggest that both estradiol and iCR confer a protective effect on the lacrimal and submandibular glands of ovariectomized rats via different mechanisms.