Lymphotoxin is an important T cell-derived growth factor for human B cells

Two different assays for B cell growth factors (BCGF) and an antibody against lymphotoxin were used to show that the presence of lymphotoxin in conditioned media derived from normal activated T cells and in a partially purified BCGF accounts for a substantial portion of their B cell growth-promoting activity. A competitive binding assay confirmed the presence of significant amounts of lymphotoxin in the partially purified BCGF. Recombinant lymphotoxin enhanced the proliferation of activated B cells and augmented B cell proliferation and immunoglobulin secretion induced by interleukin-2.     

Thyroid hormone induction of an autocrine growth factor secreted by pituitary tumor cells

Thyroid hormones stimulate the rate of cell division by poorly understood mechanisms. The possibility that thyroid hormones increase cell growth by stimulating secretion of a growth factor was investigated. Thyroid hormones are nearly an absolute requirement for the division of GH4C1 rat pituitary tumor cells plated at low density. Conditioned media from cells grown with or without L-triiodothyronine (T3) were treated with an ion exchange resin to remove T3 and were tested for ability to stimulate the division of GH4C1 cells. Conditioned medium from T3-treated cells was as active as thyroid hormone at promoting GH4C1 cell growth but did not elicit other thyroid hormone responses, induction of growth hormone, and down-regulation of thyrotropin-releasing hormone receptors, as effectively as T3 did. A substance or substances associated with T3-induced growth stimulatory activity migrated at high molecular weight at neutral pH and was different from known growth-promoting hormones induced by T3. The results demonstrate that thyroid hormones stimulate the division of GH4C1 pituitary cells by stimulating the secretion of an autocrine growth factor.     

植物提取物的生物学功能及其在肉鸡生产中的应用进展

植物提取物是通过物理化学等方式从植物中提取的一类单一或混合的化合物,具有促生长、抗氧 化、抗菌、抗病毒和增强免疫等生物学功能。植物提取物作为饲料添加剂,可提高肉鸡的生长性能,改善肉品质, 提高机体抗氧化能力和免疫力,维持肠道健康等。植物提取物的提取工艺、提取物中的活性成分和试验条件等 因素影响植物提取物的作用效果。总结了植物提取物的生物学功能、影响因素及其在肉鸡生产中的应用,为植 物提取物更广泛应用在肉鸡生产上提供依据。     

Kaposi's sarcoma cells: long-term culture with growth factor from retrovirus-infected CD4+ T cells

Studies of the biology and pathogenesis of Kaposi's sarcoma (KS) have been hampered by the inability to maintain long-term cultures of KS cells in vitro. In this study AIDS-KS-derived cells with characteristic spindle-like morphology were cultured with a growth factor (or factors) released by CD4+ T lymphocytes infected with human T-lymphotropic virus type I or II (HTLV-I or HTLV-II) or with human immunodeficiency virus type 1 or 2 (HIV-1 or HIV-2). Medium conditioned by HTLV-II-infected, transformed lines of T cells (HTLV-II CM) contained large amounts of this growth activity and also supported the temporary growth of normal vascular endothelial cells, but not fibroblasts. Interleukin-1 and tumor necrosis factor-alpha stimulated the growth of the KS-derived cells, but the growth was only transient and these could be distinguished from that in HTLV-II CM. Other known endothelial cell growth promoting factors, such as acidic and basic fibroblast growth factors and epidermal growth factor, did not support the long-term growth of the AIDS-KS cells. The factor released by CD4+ T cells infected with human retroviruses should prove useful in studies of the pathogenesis of KS.     

Extended culture of mouse embryo cells without senescence: inhibition by serum

Mouse embryo cells cultured in vitro in serum-supplemented media undergo growth crisis, resulting in the loss of genomically normal cells prior to the appearance of established, aneuploid cell lines. Mouse embryo cells established and maintained for multiple passages in the absence of serum did not exhibit growth crisis or gross chromosomal aberration. Cells cultured under these conditions were dependent on epidermal growth factor for survival. Proliferation was reversibly inhibited by serum or platelet-free plasma, suggesting that mouse embryo cultures maintained by conventional procedures are under the influence of inhibitory factors.     

RH 5849, a nonsteroidal ecdysone agonist: effects on a Drosophila cell line

The steroid molting hormone 20-hydroxyecdysone is the physiological inducer of molting and metamorphosis in insects. In ecdysone-sensitive Drosophila Kc cells, the insecticide RH 5849 (1,2-dibenzoyl-1-tert-butylhydrazine) mimics the action of 20-hydroxyecdysone by causing the formation of processes, an inhibition of cell proliferation, and induction of acetylcholinesterase. RH 5849 also competes with [3H]ponasterone A for high-affinity ecdysone receptor sites from Kc cell extracts. Resistant cell populations selected by growth in the continued presence of either RH 5849 or 20-hydroxyecdysone are insensitive to both compounds and exhibit a decreased titer of measurable ecdysone receptors. Although it is less potent than 20-hydroxyecdysone in both whole-cell and cell-free receptor assays, RH 5849 is the first nonsteroidal ecdysone agonist.     

Differentiation of murine bone marrow stem cells in vitro: long-term growth promoted by a lymphocyte-derived mediator

In attempts to induce differentiation of lymphoid cells from hematopoietic stem cells in vitro, the effects of allogeneic effect factor on the growth of murine bone marrow cultures were studied. Allogeneic effect factor is a soluble mediator derived from mixed secondary murine leukocyte cultures. For several weeks it supported the growth of bone marrow cultures, as indicated by the maintenance of stem cell activity, cellular proliferation, and heterogeneity. Another lymphokine, T cell growth factor, did not, Pre-T lymphocytes could be detected in these cultures for several weeks.     

Production of mammastatin, a tissue-specific growth inhibitor, by normal human mammary cells

The growth of human mammary cells may be regulated by a balance between growth stimulatory and growth inhibitory pathways. Polypeptides of 47 and 65 kilodaltons (mammastatin) were isolated from conditioned medium of normal human mammary cells. Monoclonal antibodies against mammastatin were generated that blocked its activity and were used for purification and further characterization of the protein. Mammastatin inhibited the growth of 5 transformed human mammary cell lines, but had no effect on the growth of 11 transformed human cell lines derived from nonmammary tissues. Mammastatin appeared to be a heat-labile protein distinct from transforming growth factor-beta (TGF-beta). By immunoperoxidase staining it was detected in cultured normal human mammary cells, but was decreased in transformed mammary cells.     

牛初乳生物因子提取物对人体肠道细胞CaCO-2生长性能的影响

初乳是自然界中唯一含有两类主要生长因子(类胰岛素生长因子和转化生长因子)的天然产物。乳源生长因子对人体肠道具有显著的生理功能,可使新生幼体完成从胎盘营养到肠道营养的转变。本研究以CaCO-2细胞系作为人体肠道细胞模型,测定初乳乳清、乳清超滤物和乳清阳离子交换提取物对人体肠道细胞代谢活性和DNA复制能力的影响。结果表明,初乳乳清超滤物(截留分子质量990ku)0.01μg·mL-1条件下,具有最高的促细胞代谢活性,为10%胎牛血清的1.70倍。乳清阳离子交换提取物在更低的浓度下具有活性。酸乳清100ku超滤滤出物在0.01μg·mL-1质量浓度下,具有10%胎牛血清2.57倍促DNA复制活性。     

Serum induced lymphoid cell mediated cytotoxicity to human transitional cell carcinomas of the genitourinary tract

In some serums of patients with transitional cell carcinoma (TCC), a factor is present which induces lymphocytes from most donors with or without TCC to become cytotoxic against TCC-derived target cells. The induced cytotoxicity was directed against target cells derived from TCC's of the renal pelvis, ureter, and urinary bladder, but not against cells derived from normal kidney, bladder, testis, or skin or from renal cell carcinoma. Cytotoxicity occurred without complement but did not occur without effector cells.     

Growth factors modulate gonadotropin receptor induction in granulosa cell cultures

Epidermal growth factor and fibroblast growth factor inhibited follicle-stimulating hormone-dependent induction of luteinizing hormone receptor in cultured ovarian granulosa cells of the rat. In contrast, platelet-derived growth factor potentiated the induction of luteinizing hormone receptor by follicle-stimulating hormone. These results indicate that growth factors, well known for their effects on mitosis and DNA synthesis in cultured mammalian cells, are also able to modulate hormone-dependent differentiation in an endocrine target cell.     

番茄内生细菌的分离及其促生活性研究(英文)

[Objective] The study aimed to investigate the growth-promoting activities of endophytic bacteria from tomato plants.[Method]The endophytic bacteria isolated from different tissues of tomato plants were analyzed for the effects of their growth-promoting activities on the germination and growth of tomato plants.The bacteria with growth-promoting activity were preliminarily identified.[Result]Totally 59 endophytic bacterial strains were isolated from roots and stems of tomatoes,of which 4 showed significantly growth-promoting activity to germination and growth of tomato.The results suggest that these strains are endowed with the potential capability of growth-promoting.[Conclusion]The endophytic bacteria with growth-promoting activity were found among the isolates from tomato plants.This provided a good foundation for utilization of these bacteria with growth-promoting activity.     

生长因子和激素对大菱鲆细胞生长的影响

研究了不同浓度生长因子、激素和条件培养基对大菱鲆Scophthatmus maximus鳍、鳃和肾组织原代培养细胞生长和增殖的影响。结果表明：当氢化可的松（HC）浓度为0.4μg/mL时,鳍、鳃组织贴壁率和迁出率最高,分别为89.4%、53.3%和92.3%、59.6%,浓度为0.8μg/mL时,肾细胞的增殖量最大;当表皮生长因子（EGF）浓度为10 ng/mL时,鳍、鳃组织块的贴壁率和迁出率均达到最高,分别为85.9%、54.6%和88.1%、56.8%,肾细胞的增殖量最大;当胰岛素（Ins）浓度为5μg/mL时,鳍、鳃组织块的贴壁率和迁出率均达到最高,分别为90.8%、52.3%和92.3%、54.2%,肾细胞的增殖量也达到最大值;当sp2/0条件培养基的添加比例为1/5时,鳍和鳃组织块的贴壁率均达到最高（96.8%和92.8%）,鳃的迁出率最高,为59.3%,肾细胞的增殖量最大;sp2/0条件培养基比例为1/4时,鳍的迁出率最高（52.3%）。     

紫光对斑马鱼皮肤黑色素细胞数量及相关基因表达的影响

利用CRISPR/Cas9基因编辑技术构建感紫光短波视蛋白(short-wave-sensitive 1,sws1)基因缺失的斑马鱼突变品系sws1^-/-。检测紫光照射后野生型AB品系和sws1^-/-突变品系在背腹皮肤中黑色素细胞的数量、黑色素合成相关基因pomc和asip、视黄酸合成相关基因raldh2和raldh3的表达量。结果显示:在紫光照射60和100 d后,sws1^-/-斑马鱼背部皮肤黑色素细胞数量显著少于野生型斑马鱼(P<0.05);实时荧光定量PCR (qRT-PCR)检测发现,pomc基因在紫光照射100 d的sws1^-/-斑马鱼背部皮肤中的表达量显著低于野生型,raldh2在紫光照射100 d的sws1^-/-斑马鱼背部皮肤中的表达量显著低于野生型。研究表明,紫光可能通过SWS1影响背部皮肤raldh2的表达从而影响视黄酸的合成,再通过影响pomc的表达调控黑色素细胞的形成。研究结果为分析紫光基因调控鱼类皮肤黑色素细胞形成的分子机制提供了基础。     

Induction by soluble factors of organized axial structures in chick epiblasts

Inductive action of soluble factors was tested on isolated chick epiblasts. An assay was developed wherein conditioned medium derived from the Xenopus XTC cell line induced the formation of a full-length notochord and rows of bilaterally symmetric somites. Basic fibroblast growth factor, epidermal growth factor, retinoic acid, and transforming growth factor type B1 and B2 were not capable of inducing axial structures. Thus, soluble factors can elicit the development of polarity stored in the epiblast and behave as true morphogens since they can induce the formation of the organized complex structures that constitute the embryonic axis.     

Reversal of creatine kinase translational repression by 3' untranslated sequences

A subline of U937 cells (U937D) was obtained in which creatine kinase B (CK-B) messenger RNA was present and bound to ribosomes, but CK activity was undetectable. Transformation of U937D cells with retrovirus vectors that contain the 3' untranslated region (3' UTR) of CK-B messenger RNA exhibited CK activity with no change in abundance of CK-B mRNA. The 3' UTR formed a complex in vitro with a component of S100 extracts from wild-type cells. This binding activity was not detectable in S100 extracts from cells that expressed CK activity after transformation with the 3' UTR-containing vector. These results suggest that translation of CK-B is repressed by binding of a soluble factor or factors to the 3' UTR.     

黄瓜根际促生真菌的筛选及促生效应研究

[目的]筛选黄瓜根际促生真菌,并探索其促生效应。[方法]以解磷、产IAA和拮抗黄瓜枯萎病菌能力为筛选标准测定初筛菌株的多项促生能力;通过种子萌发和盆栽试验测定菌株对黄瓜的促生效应;通过形态鉴定和r DNA-ITS序列分析对促生菌株进行分类学鉴定。[结果]从连作黄瓜根际土壤中分离到1株同时具解磷、产IAA和拮抗黄瓜枯萎的真菌,该菌株孢子悬浮液能有效促进黄瓜种子萌发和幼苗生长。形态学和分类学鉴定结果显示该菌株为哈茨木霉(Trichoderma harzianum)。[结论]所筛选的促生真菌能有效改善黄瓜连作障碍,为开发研制黄瓜专型促生制剂提供良好的种质资源。     

核桃根、茎、叶提取物对蚕豆的遗传毒性分析

[目的]研究核桃根、茎、叶不同提取物的化感作用机制,为开发新型无公害植物源除草剂提供科学依据.[方法]采用蚕豆根生长试验和蚕豆微核试验,测定核桃根、茎、叶不同提取物对蚕豆生长的影响和遗传毒性.[结果]经核桃根、叶正丁醇提取物培养24和48h的蚕豆根生长减慢,当核桃根、叶正丁醇提取物浓度大于0.050 g/mL时,培养72 h的蚕豆根生长停滞.微核试验结果,核桃根、叶正丁醇提取物能抑制蚕豆根尖细胞生长,损伤其遗传物质,导致其有丝分裂指数下降、微核率增高,与对照相比呈显著性差异(P<0.05),且在试验浓度范围内(0.025~0.100 g/mL)表现出显著的浓度效应和时间效应.[结论]核桃根和叶中含有一定遗传毒性的化感物质,能够抑制植物细胞分裂,导致细胞遗传物质损伤,对周围植物产生不可逆的遗传损伤效应.