Heavy Metal Toxicity and Iron Chlorosis

1. The toxicity of copper, nickel, cobalt, zinc, chromium, andmanganese to mustard was studied in water culture, utilizingeither the ionic form or the EDTA chelate of the metal in thepresence of either ferric chloride or ferric EDTA. 2. In presence of ferric chloride the activity of the metalsin producing chlorosis was as given above, i.e. in the orderof stability of their chelates. In the presence of ferric versenate,toxicity of the ionic metal was much reduced. The metal chelatesgave very little indication of toxicity with either form ofiron. 3. It was found that the ratio of total phosphorus to totaliron was higher in chlorotic plants than in green plants, irrespectiveof which metal was causing the toxicity. 4. Copper could be demonstrated in the phloem cells of the rootusing bis-cyclohexanone-oxalydihydrazone as histochemical reagent.It is postulated that transport of iron probably takes placein the phloem as an active process. 5. It would appear that as a major part of the iron in plantcells is attached to nucleo- or phospho-proteins, the heavymetals must be similarly attached to phospho-proteins.     

MDCK细胞微载体悬浮培养放大工艺研究

MDCK细胞对各种流感病毒具有高度敏感性,广泛应用于流感病毒的分离和疫苗制备.通过探索培养基中促进细胞贴壁的关键组分,并筛选水解物,开发了适合MDCK细胞生长的低血清培养基.发现钙、镁离子是细胞贴壁不可缺少的物质,麦麸水解物可以部分代替培养基中的血清.利用该低血清培养基,经过消化转移将MDCK细胞从5L反应器放大至25 L反应器,微载体上细胞贴附均匀、生长旺盛,25 L反应器中培养48 h细胞密度可达30.5×105 cells/ml.研究结果为工业规模反应器微载体悬浮培养MDCK细胞生产流感病毒奠定了基础.     

微载体培养技术的研究进展

本文对近年来广泛用于动物细胞培养的微载体技术的特点、培养过程的优化作了较为详细的评述。     

Decorporation Approach Following Rat Lung Contamination with a Moderately Soluble Compound of Plutonium Using Local and Systemic Ca-DTPA Combined Chelation

Decorporation efficacy of prompt pulmonary delivery of DTPA dry powder was assessed following lung contamination with plutonium nitrate and compared to an intravenous injection of DTPA solution and a combined administration of both DTPA compounds. In addition, efficacy of a delayed treatment was assessed. In case of either early or late administration, insufflated DTPA was more efficient than intravenously injected DTPA in reducing the plutonium lung burden due to its high local concentration. Prompt treatment with DTPA powder was also more effective in limiting extrapulmonary deposits by removing the early transportable fraction of plutonium from lungs prior its absorption into blood. Translocation of DTPA from lungs to blood may also contribute to the decrease in extrapulmonary retention, as shown by reduced liver deposit after delayed pulmonary administration of DTPA. Efficacy of DTPA dry powder was further increased by the combined intravenous administration of DTPA solution for reducing extrapulmonary deposits of plutonium and promoting its urinary excretion. According to our results, the most effective treatment protocol for plutonium decorporation was the early pulmonary delivery of DTPA powder supplemented by an intravenous injection of DTPA solution. Following inhalation of plutonium as nitrate chemical form, this combined chelation therapy should provide a more effective method of treatment than conventional intravenous injection alone. At later stages following lung contamination, pulmonary administration of DTPA should also be considered as the treatment of choice for decreasing the lung burden.     

用多孔微载体Cytopore高密度培养CHO工程细胞生产rHEPO

在２．２Ｌｃｅｌｉｇｅｎ灌注培养系统中采用Ｃｙｔｏｐｏｒｅ多孔微载体培养产重组人促红细胞生成素（ｒＨＥＰＯ）的细胞Ｃ２。细胞密度达到１×１０７／ｍＬ,ｒＨＥＰＯ最高可达９．７ｍｇ／Ｌ。该载体具有表面积高,使用浓度低,便于扩大培养的特点,便于进行大规模培养     

纳米铁氧化物磁热疗相关机制研究进展

热疗作为继手术、放疗和化疗后的肿瘤治疗的重要方法之一,自其诞生之初便受到研究人员和产业部门的关注.磁热疗目前已经应用到前列腺癌、脑部肿瘤等临床实验或治疗中,并取得较好的疗效.本文主要介绍基于磁性纳米颗粒的磁热疗产热物理机制与影响因素,以及磁热的亚细胞水平生物学效应.     

Sporicidal Activity of Alkaline Alcoholic Saturated Dialdehyde Solutions

During a search for a sporicidal agent to equal or surpass formaldehyde in activity, a group of saturated dialdehydes ranging from two to six carbons was discovered. These dialdehydes exerted a surprisingly high degree of activity in isopropanol buffered with a carbonate or bicarbonate. Without the proper buffer, practically no activity was observed. A solution of 1% glutaraldehyde, 0.3% NaHCO₃, and 70% isopropanol sterilized stainless-steel penicylinders contaminated with standardized numbers of four spore types in a shorter time than did commercially available 8% formaldehyde solution. Both glyoxal and glutaraldehyde in isopropanol destroyed spores in a relatively short time. Care was taken to eliminate bacteriostasis. Various tests were performed to evaluate accurately experimental and formaldehyde solutions.     

Microcarrier culture of vascular endothelial cells on solid plastic beads

The culture of vascular endothelial cells on solid plastic beads is described. A greater than 30-fold increase in cell numbers was achieved in stationary culture medium. The inclusion of fibroblast growth factor slightly improved the rate of growth from low densities. Addition of fresh beads to colonized beads resulted in colonization of the newly introduced microcarrier. In common with the behaviour of endothelium in conventional culture, the cells cultured on beads changed from a fusiform to a polygonal shape after reaching confluence. Cell proliferation was also observed by [³H]thymidine autoradiography of DNA. The fraction of radiolabelled nuclei declined at confluence on each bead, indicating density-inhibition of growth. By electron microscopy, the cells displayed the typical ultrastructural appearance of endothelium. Following transfer of colonized beads to a chromatography column with slow perfusion of the bead bed, cell viability was maintained over a 24 h period and proportional synthesis of prostaglandin I₂ upon stimulation by ionophore A23187 was demonstrated. This simple microcarrier technique allows the generation of large numbers of vascular endothelial cells for subcellular fractionation with economical use of space and medium. When set up as a perfused bead bed, it offers possibilities for the short-term collection of concentrated endothelial metabolites.     

用微载体技术培养家蚕BmN细胞的实验研究

观察了家蚕BmN(从silkworm Bombyxmori获得的细胞系)细胞在微载体cytodex3上的贴壁分布,提出其分布符合Poisson规律．并由此估计了不同细胞接种浓度时裸球的百分比．与实际观测结果基本符合;研究了不同接种浓度与微载体浓度时细胞的生长情况,家蚕BmN细胞在Cytodex 3上生长的临界接种数为一珠粒6．4个细胞。当微载体浓度为3 g／L时,最低的接种浓度为1．O×10⁵／ml。     

Fluorescent Derivatives of Polysaccharide Dialdehyde as Substrates for Glucanases

A simple and sensitive assay method for glucanase activity was established using fluorescent polysaccharide substrates. Periodate oxidized α-glucans having dialdehyde were covalently attached to the fluorescent reagent via Schiff base formation followed by NaBH₄ reduction. Ethylenediaminonaphthalene (EDAN) was effective to produce a stable and highly fluorescent polysaccharide. EDAN derivatives of glycogen and dextran dialdehyde were useful substrates for Taka-amylase A and endodextranase, respectively. Two cellulases were shown to release water-soluble fluorescent products from the EDAN derivative of cellulose powder. Moreover, the action of the exo type of enzyme such as glucoamylase was readily distinguished from that of the endo type of enzyme because the attached EDAN prevented the attack of exo-enzyme.     

基于魔芋葡甘聚糖微球的胶原覆层型微载体的制备研究

以魔芋葡甘聚糖(KGM)微球为基质,用1,4-丁二醇二缩水甘油醚将KGM微球进行活化,将胶原覆层到微球上,对胶原覆层进行再次交联,得到覆层均匀、稳定的微载体.通过四因素三水平的正交回归组合试验设计,考察了活化时间、蛋白质用量、偶联时间、交联剂用量对微载体细胞培养效果的影响.以Vero细胞培养效果为指标,制备胶原包被微载体的最佳工艺为活化时间5h、蛋白用量1∶0.1(球:蛋白)、偶联时间5h、交联剂用量每1gKGM加入0.5ml交联剂.在最优制备条件下,培养Vero细胞最大细胞密度可达到1.7×106 cells/ml,证明了胶原覆层的KGM微球作为动物细胞培养的微载体具有可行性.     

Obtaining of Metal Nanoparticles Using Reducing Agents and Chitosan

Applied Biochemistry and Microbiology - Unique features of metal nanoparticles (NPs) are attracting the attention of researchers from various fields of science, including biomedicine, microbiology,...     

二价金属离子转运蛋白1——一个新发现的重要铁转运蛋白

二价金属离子转运蛋白1(divalent metal transporter 1,DMT1)的发现是近年铁代谢研究领域最重大的一项突破.DMT1是哺乳类跨膜铁转运蛋白.这种蛋白质广泛分布于人体各组织.DMT1 mRNA有两种形式,一种含有IRE(iron response element),而另一种则不含此结构.DMT1的功能主要是介导小肠上皮细胞的铁吸收以及参与铁从内吞小体移位到胞浆的过程.DMT1介导的铁转运是一个主动的和H⁺依赖的过程.DMT1也参与其他二价金属如Zn²⁺、Mn²⁺、Co²⁺、Cd²⁺、Cn²⁺、Ni²⁺和Pb²⁺的转运.小肠DMT1的表达受饮食或组织铁控制.第四跨膜区是DMT1的重要功能区.此区基因发生点突变（G185R）是导致不可逆性缺铁性贫血的原因.在帕金森氏病人的黑质发现DMT1表达异常增加,因而DMT1可能也与某些神经退行性疾病的形成有关.