一种植物由来的糖蛋白(郑氏植物蛋白)--肿瘤相同性抗原的研究

目的：研究一种植物提取物的肿瘤相同抗原性及其在肿瘤早期诊断上的应用。方法：采用^3H掺入法测定了淋巴细胞和肿瘤细胞增殖反应；将人新鲜肿瘤组织块移植于小鼠，观察肿瘤在异种动物体内成活情况。瘤细胞DNA含量用流式细胞仪测定。通过凝胶层析及SDS-PAGE等方法对该提取液进行了化学成分鉴定。结果：该植物提取物对恶性肿瘤和癌前病变患者的淋巴细胞增殖有很强的刺激作用(P＜0．01)，但对正常人淋巴细胞无刺激作用。提取物对70％以上肿瘤患者的肿瘤细胞增殖有刺激作用。将人新鲜肿瘤组织块移植到经该提取物预处理的幼鼠后，成活率达90％以上，而且可以成功传代；未经提取物预处理的小鼠，30天后肿瘤组织死亡而被吸收。经初步鉴定，该提取物的化学成分为50kD的糖蛋白。结论：该植物糖蛋白具有肿瘤抗原活性或肿瘤相同抗原性，这种特性可应用于肿瘤诊断、治疗和肿瘤疫苗制备等。     

Food Allergy Overview in Children

Food allergies have increased significantly in the past decade. An accurate history is crucial in approaching the management. At the outset, food intolerance must be distinguished from food allergies and, furthermore, these allergies should be classified into either an IgE, Non-IgE, or a mixed response. The clinical features vary from life-threatening anaphylaxis to milder IgE-mediated responses, atopic dermatitis, and gastrointestinal symptoms. The severity of the reaction and the potential risk for anaphylaxis on reexposure should be assessed. Milk, soy, egg, wheat, and peanut allergies are common in children, whereas peanut, tree nut, fish, shell fish allergies, and allergies to fruits and vegetables are common in adults. Structural proteins are important determinants of the severity of the reactions and may often predict the natural history and cross reactivity. Diagnostic work up must be guided by the clinical history. Skin testing and food-specific IgE done by standard methods are very useful, whereas oral challenges may be indicated in some situations. Majority of the patients outgrow their allergies to milk, soy, egg, and wheat, and some to peanut also, therefore, patients should be periodically reassessed. Novel diagnostic techniques which detect specific allergenic epitopes have been developed. Several newer therapies are promising.     

Placenta hominis protects osteoporosis in ovariectomized rats

In China, Japan, and Korea, placenta hominis extracts (PHEs) are used clinically for the treatment of osteoporosis. The anti-osteoporotic effect of PHEs was studied. The trabecular bone area and thickness in OVX rats decreased by 50% from those in sham-operated rats; these decreases were completely inhibited by administration of PHEs for 7 weeks. Osteoclast numbers and the osteoblast surface were enhanced in OVX rats, but PHEs had no effect on these phenomena. Serum phosphorus and alkaline phosphatase in OVX rats increased compared to those in sham-operated rats, but the increases were not affected by the administration of PHEs. Thyroxine (T₄) level was stimulated in OVX rats. The extracts inhibited the T₄ level in the OVX rats. These results strongly suggest that PHEs be effective in preventing the development of bone loss induced by OVX in rats.     

Innate immune memory in plants

The plant innate immune system comprises local and systemic immune responses. Systemic plant immunity develops after foliar infection by microbial pathogens, upon root colonization by certain microbes, or in response to physical injury. The systemic plant immune response to localized foliar infection is associated with elevated levels of pattern-recognition receptors, accumulation of dormant signaling enzymes, and alterations in chromatin state. Together, these systemic responses provide a memory to the initial infection by priming the remote leaves for enhanced defense and immunity to reinfection. The plant innate immune system thus builds immunological memory by utilizing mechanisms and components that are similar to those employed in the trained innate immune response of jawed vertebrates. Therefore, there seems to be conservation, or convergence, in the evolution of innate immune memory in plants and vertebrates.     

Screening 34 Peanut Introductions for Allergen Content Using ELISA

Peanut is one of the most allergenic foods and reports of accidental ingestion of peanuts in unsuspected food are increasing. No information is available on the allergen content of peanut germplasm grown commercially and used in the food and confectionery industry. The objectives of this study were: (1) to determine the allergen contents of 34 peanut introductions (PI); and (2) to identify naturally occurring allergen-free and/or low or hypoallergenic peanuts germplasm. A basic ELISA protocol was utilized to detect the presence of antigens in the peanut lines using a pool of human sera from patients with documented history of peanut allergy. Two naturally occurring low, or hypo-allergenic germplasm were identified as PI 261942 and PI 338386. Both are Valencia market types with total allergen content significantly lower (P ≤0.05) than that of PI 119880 (0.550), PI 119876 (0.415) and PI 118991 (0.410) three Valencia market types and PI 262111 (0.485), a Virginia market type. No allergen-free PI was found. Allergen content of peanut lines from Bolivia and Paraguay were significantly (P ≤0.05) different to those from Venezuela. No significant difference was observed in the allergen content of the four market types.     

植物抗体及其应用

20世纪80年代末科学家将抗体基因转入烟草表达,标志着植物抗体的诞生.人类既可以以植物为生物反应器异源表达和生产具有药用及商业价值的蛋白质;也可用抗体在植物体中进行免疫调节,以研究植物生理代谢机制,或增加植物抵抗病虫害的能力.本文旨对植物抗体的优越性、表达生产及其在医药学、植物抗病及代谢等领域的进展进行综述和讨论.     

蒙药材瑞香狼毒体外细胞毒性的研究

目的研究蒙药瑞香狼毒炮制前后的体外细胞毒性和抗肿瘤活性。方法利用石油醚、醋酸乙酯和正丁醇分别萃取获得瑞香狼毒药材生品、奶制品、煎膏制品的各溶剂提取物,再通过萃取、分离纯化方法分别获得瑞香狼毒的9个单体化合物、总蛋白质和6个相对分子质量不同的蛋白质组分(Pr.1~Pr.6)。将各溶剂提取物及单体化合物制成浓度为2.0mg/ml的溶液,总蛋白质制成浓度分别为0.5、1.0、2.0、4.0、6.0、8.0mg/ml的系列溶液,各蛋白质组分制备成浓度均为10mg/ml的溶液,分别作为样品溶液,采用MTT法分别测定各样品对人肝癌SMMC-7721细胞、狗肾MDCK细胞的生长抑制作用。结果瑞香狼毒总蛋白质抗肿瘤活性和细胞毒性作用随其浓度增加而增强,其中4个蛋白质组分呈现较强的抗肿瘤活性,其活性由强至弱依次为Pr.4≥Pr.6≥Pr.3=Pr.2,3个蛋白质组分具有细胞毒性,其毒性由强至弱依次为Pr.4≥Pr.3≥Pr.1。瑞香狼毒单体化合物中,西瑞香素、狼毒色原酮、异狼毒素呈现不同程度的抗肿瘤活性,而狼毒色原酮、异狼毒素同时具有较弱的细胞毒性。除石油醚和多糖提取物外,瑞香狼毒药材生品各溶剂提取物均呈现不同程度的抗肿瘤活性和细胞毒性,并呈药物剂量依赖性;而炮制后,在保留一定程度抗肿瘤活性的基础上,其相应各溶剂提取物的细胞毒性均降低。结论瑞香狼毒的细胞毒性主要源自多成分的协同作用,其蛋白质可能是瑞香狼毒的主要毒性位点之一,而炮制方法可降低瑞香狼毒药材的毒性且保留其生物活性。     

ER membrane aquaporins in plants

Plant has a large aquaporin family with more than 30 members which are divided into four subfamilies: plasma membrane intrinsic protein (PIP), tonoplast intrinsic protein (TIP), nodulin 26-like intrinsic proteins (NIP), and small and basic intrinsic proteins (SIP). Their primary structure, transport substrate, functional regulation, gene expression profile, protein amount, and intracellular localization are diversified. The SIP members have short N-terminal tails. Most aquaporins have two sets of common Asn-Pro-Ala (NPA) motif; however, the first motif of SIP1;1, SIP1;2, and SIP2;1 is changed to NPT, NPC, and NPL, respectively. SIP1;1 and SIP1;2, but not SIP2;1, have water transport activity. A recent study revealed that all three members of SIP are localized to the ER membrane and expressed in a cell specific manner in Arabidopsis thaliana. An overview is given on the main features of the SIP members in terms of their primary structure, ER membrane retention, homologues in mammals, and physiological function.