用两个不同种的土壤农杆菌Agrobacterium tumefaciens和A.rhizogenes对马铃薯细胞进行复合转化的研究

致癌土壤农杆菌Agrobacterium tumefaciens和致根土壤农杆菌A.rhizogenes都具有将其T—DNA整合到植物染色体上,从而对植物细胞进行遗传转化的能力,在植物遗传工程的研究中具有重要意义。本文报道了用这两个不同种的土壤农杆菌,用两种不同的复合侵染方法,对马铃薯块茎切块的细胞进行复合转化的研究结果。一步侵染法是将这两个不同种的细菌悬浮液混合以后,接种于马薯块茎切块上;两步侵染法是先用致根土壤农杆菌侵染马铃薯块茎切块,得到转化的毛根并在无激素的培养基上继代培养无菌毛根一年以后,再将毛根切段用致癌土壤农杆菌接种。对转化细胞特殊标记物质Opine进行电泳分析的结果表明,这两种侵染方法都可以得到复合转化的马铃薯细胞和组织。但是,一步法比两步法具有更多的优越性。这种复合转化现象对于在植物遗传工程的研究中,一次转移多个基因具有重要的意义。     

Carcinogen-induced immune depression: absence in mice resistant to chemical oncogenesis

Administration of 3-methylcholanthrene 6 days before antigenic challenge depressed the immune response to sheep red cells in young adult mice (C3Hf/Bi strain) sensitive to the oncogenic effect of the drug (100 percent local tumors 240 days after carcinogen). The drug was not immunodepressant in the I strain, which is relatively resistant to its carcinogenic effect (11 percent local tumors 240 days after carcinogen).     

Carcinogenic substances from pituitary glands of cattle

Lipid extracts from the pituitary gland of cattle were prepared which, when injected into a pure strain of white mice, caused development of malignant tumors in 26.8 per cent of the 67 animals injected, which corresponds with the numerical results obtained by investigators working with human liver extracts. Evidently the carcinogenic power of these lipid extracts is low. The tumors developed chiefly in organs at a distance from the site of injection, exhibiting various histological types including carcinoma as well as sarcoma. The tumors developed at an earlier date after injection of extracts from the anterior lobe as compared with those developing after injection of the posterior lobe extracts, the average period of time necessary for their development being 9.3 months for the anterior lobe extracts and 14 months for posterior lobe extracts.     

Suppression of urethan-induced lung adenomas in mice treated with trehalose-6,6-dimycolate (cord factor) and living bacillus Calmette Guérin

Trehalose-6,6-dimycolate (cord factor), a glycolipid from mycobacteria, suppressed the development of urethan-induced tumors in the lungs of mice to a similar degree as living Mycobacterium bovis (strain BCG) bacilli. The inhibition was apparently due to the host cellular reaction caused locally by cord factor.     

Immunotherapy of cancer: regression of tumors after intralesional injection of living Mycobacterium bovis

Injection of living Mycobacterium bovis (strain BCG) into established intradermal tumors caused tumor regression and prevented the development of metastases.     

接种不同毒力马立克氏病毒对鸡端粒酶活性和致病性的影响

以MDV京-1株和GA株诱发的MD为肿瘤模型,跟踪测定了鸡生长过程中脾脏组织的端粒酶活性变化。结果表明,端粒酶活性在没有临床症状和可视病变出现之前便可检测到。随着MDV感染日龄的增加逐渐升高,在其相对活力达到最高值后,总体水平略有下降,但依然存在端粒酶活性;而疫苗株CVI988接种后,整个生长过程其端粒酶均呈阴性。发生MD病变的鸡生长迟缓,中枢性免疫器官胸腺和法式囊严重萎缩,并出现体内肿瘤。无论是病变程度,还是死亡个数和时间,京-1株的致病性均高于GA株。     

甘肃省动物肿瘤病的发生与动物种属之间的相关性

通过对甘肃省兰州、白银、武威、酒泉、天水等地动物肿瘤病近２０年发生情况调查统计，发现甘肃省动物的一些肿瘤与动物种属有明显的相关性，调查统计涉及的动物有１１种，检出良性肿瘤１６种、恶性肿瘤２３种，检出率最高的肿瘤是鸡马立克氏病。各种动物的好发肿瘤：马属动物－纤维瘤、黑色素瘤、乳头状瘤、纤维肉瘤、恶性黑色素瘤；牛－乳头状瘤、纤维瘤、鳞癌、瞬膜癌；羊－肺腺瘤病、山羊会阴癌；鸡－马立克氏病、淋巴肉瘤；双峰驼－肝脂肪瘤；鱼－骨瘤；猪、兔检出类型少，检出率也较低。值得注意的是上述１３种肿瘤中８种是皮肤肿瘤，并主要发生于大家畜马属动物、牛和羊，这一特点可能与甘肃省地处高原地带，家畜长期遭受紫外线照射密切相关。     

苹果多酚对小鼠H22细胞株移植性肿瘤的抑制作用

[目的]观察苹果多酚对小鼠H22细胞株移植性肿瘤的抑瘤作用,为进一步研究其抗肿瘤机制提供参考。[方法]以CTX为对照,研究灌胃不同剂量苹果多酚溶液对小鼠H22细胞移植性肿瘤的抑制作用及其对EAC腹水型小鼠生命延长率的影响。[结果]大、中、小剂量苹果多酚对}122实体瘤的体内抑瘤率分别为48．70％、62．12％、42．97％,但效果均不如CTX（76．11％）。随着给药时间的延长,肿瘤的大小与空白对照组相比均有明显的减小,但剂量-效应关系不明确。经大、中、小剂量苹果多酚处理后,EAC腹水型小鼠模型的平均存活天数分别为15．43、16．05和17．51d,均高于空白对照组（15．51d）,但均低于CTX对照组（20．67d）,生命延长率分别为3．06％、7．78％、15．31％,也无明确的剂量-效应关系。[结论]苹果多酚在体内对H22移植性肿瘤具有良好的抑制作用,但其剂量一效应关系不明确;对于荷EAC小鼠的生存时间无显著影响。     

Pituitary tumors in mice after prolonged feeding of synthetic progestins

An enhanced development of pituitary tumors was observed in virgin female mice of the C57 Leaden strain following repeated oral administration of synthetic progestins. This finding appears to parallel the co-carcinogenic enhancement of mammary tumor development elicited in C3H mice treated repeatedly with progesterone.     

携带CD自杀基因NDV重组病毒对小鼠肝癌细胞转移模型的治疗效果

采用反向遗传操作技术构建新城疫病毒基因组NP/P位点表达胞嘧啶脱氨酶(Cytosine deaminase,CD)基因弱毒力重组新城疫病毒rClone30-CD和中毒力重组新城疫病毒rAnhinga-CD。MTT检测结果表明,在协同5-氟胞嘧啶(5-Fluorocytosine,5-FC)条件下,两株重组新城疫病毒可在体外有效杀伤人肝癌细胞HepG2。通过Balb/c鼠尾静脉注射小鼠肝癌细胞H22构建小鼠肝癌细胞转移模型,经重组病毒协同5-FC联合治疗,荷瘤小鼠转移肿瘤体积显著缩小、肿瘤组织出现明显凋亡与坏死。体内试验结果表明,中毒力重组新城疫病毒rAnhinga-CD抑瘤效果优于弱毒力重组新城疫病毒r Clone30-CD。     

Leukemogenic activity of filtrates from radiation-induced lymphoid tumors of mice

Cell-free filtrates of x-ray-induced lymphoid tumors of strain C57BL/ Ka mice have elicited, on injection into newborn isologous hosts, a lymphoma incidence of 15 to 19 percent. In control mice of the same subline, the incidence of spontaneous lymphoma is about 1 percent. No leukemogenic activity could be detected in filtrates from thymi harvested at 2 to 32 days following completion of x-ray treatment. Activity was evident at 64 days and was perhaps somewhat greater at 128 days. Serial cell-free passage of filtrates in newborn F(1) hybrid mice resulted in a marked increase in lymphoma incidence (69 percent), coupled with a shortening of the median latency. Supplementary x-irradiation failed to enhance the activity of filtrates after neonatal injection.     

Detection of a cellular oncogene in spontaneous liver tumors of B6C3F1 mice

An active cellular oncogene was demonstrated in hepatocellular neoplasms arising spontaneously in 24-month-old B6C3F1 mice. DNA isolated from the tumorous tissue and transfected into NIH 3T3 cells showed an 82 percent (9 of 11 animals) frequency of foci induction. In contrast, DNA isolated from the surrounding nontumorous hepatic tissue from the same animals and DNA from other 24-month-old B6C3F1 mice without tumors did not cause transformation in the NIH 3T3 cell assay. This strain of mouse is used extensively in carcinogen bioassays, and the observed high frequency of transformation (82 percent, compared to 10 to 20 percent in humans) supports the concept that the B6C3F1 mouse is hypersusceptible to liver tumor development. It also emphasizes the need to further understand the mechanisms of oncogene activation in animals used for long-term studies of toxicity and oncogenicity before evaluating potential human risk.     

Study on the Pathogenicity of Chinese Strains of Subgroup J Avian Leukosis Viruses

The pathogenicity of 4 Chinese strains of subgroup J avian leukosis viruses (ALV-J), SD9901,SD9902, YZ9901 and YZ9902, was studied. The results showed that only SD9902 among the 4 strains induced mortality from myeloid leukosis (ML). In the 12 meat-type chickens inoculated with SD9902 at 1-day-old, 9died between 22 days and 38 days after inoculation. No death or ML was found in chickens inoculated with the other 3 strains during the period of 6 months. These results suggested the SD9902 strain of ALV-J was an acute transforming virus, but SD9901, YZ9901 and YZ9902 were non-transforming viruses. All 4 Chinese strains did not induce any tumors in egg-type SPF chickens during 7 months after hatching when viruses were injected into 11-day-old embryos.     

Transgenic models of tumor development

Numerous cancer-prone strains of mice have been created by the introduction of candidate tumor-promoting genes into fertilized eggs. Each transgenic strain is predisposed to develop specific types of tumors, but they usually arise stochastically because of the need for spontaneous mutation of genes that collaborate with the introduced oncogene. These mice are providing insights into the effects of individual oncogenes on cellular proliferation, differentiation, and viability, as well as on oncogene cooperativity. Their predisposed state imposes sensitivity to viral and chemical carcinogenesis, and the mice should prove valuable in tests of potential carcinogens, therapies, and preventive measures.     

Human papovavirus (JC): induction of brain tumors in hamsters

Eighty-three percent of hamsters inoculated at birth with JC virus, a human papovavirus isolated from brain tissue of a case of progressive multifocal leukoencephalopathy, developed malignant gliomas within 6 months. Three brain tumors have been serially transplanted as subcutaneous tumors. JC virus was isolated from five of seven tumors tested. Cells from four tumors were cultivated in vitro. These cells contained an intranuclear antigen with the characteristics of a T antigen, and this antigen was antigenically related to SV40 T antigen. Although virus was not recovered from extracts of serially cultured tumor cells, JC virus was rescued when one tumor cell line was fused with permissive cells.     

Oncogenicity of the simian adenoviruses

Five of 17 adenoviruses of rhesus or cynomolgus monkey origin induced tumors in newborn hamsters. The tumors appeared between 42 and 280 days after subcutaneous inoculation and had the general characteristics of lymphomas. The tumors were specific by cross-complement fixation tests. An adenovirus recovered from Cercopithecus monkeys appeared to be highly oncogenic; all 23 inoculated hamsters developed tumors within 30 to 40 days.     

鸡J亚群白血病病毒与网状内皮增殖病病毒混合感染发病机理的研究

通过人工感染建立了ALV—J、REV单独感染和混合感染1日龄肉仔鸡的病理模型。初步研究表明混合感染使试验鸡的生长发育障碍、免疫器官萎缩、对细菌易感性及死亡率等指标显著升高。 动态病理学研究表明：REV感染主要引起骨髓网状细胞及淋巴样细胞弥漫性或灶状浸润,ALV—J感染主要引起骨髓髓系细胞灶状或弥漫性显著增生,混合感染时骨髓病变与REV感染基本一致,但相对较严重,并见ALV—J感染病变。各病毒感染组免疫器官均发生了严重的实质萎缩性病变,病变以混合感染组最重,REV组次之。在某些组织器官ALV—J组见嗜酸性粒细胞样的瘤细胞浸润增生,REV组见网状细胞及淋巴细胞样瘤细胞浸润增生,而混合感染组见以上两种瘤细胞增生。从混合感染组的病变来看,在致病性上ALV—J与REV之间的确存在明显的协同促进作用,导致机体的免疫抑制加重,但混合感染早期尚未发现REV对ALV—J致瘤的促进作用。     

Erythromycin-resistant mutant of Escherichia coli with altered ribosomal protein component

Erythromycin combines with 50S ribosomal subunit of an erythromycin-sensitive Escherichia coli (strain Q13), while ribosomes from an erythromycin-resistant mutant from this strain have little affinity for the antibiotic. A protein component of the 50S subunit of the mutant strain is distinct from that of the parent Q13 strain.     

Individual tumors of multifocal EB virus-induced malignant lymphomas in tamarins arise from different B-cell clones

Cotton-top tamarins were inoculated with sufficient Epstein-Barr virus to induce multiple tumors in each animal within 14 to 21 days. The tumors consisted of large-cell lymphomas that contained multiple copies of the Epstein-Barr virus genome and generated Epstein-Barr virus-carrying cell lines showing no detectable consistent chromosomal abnormality. Hybridization of tumor DNA with immunoglobulin gene probes revealed that each lymphoma was oligo- or monoclonal in origin and that individual tumors from the same animal arose from different B-cell clones. Thus the virus induced multiple transformation events in tamarins in vivo to cause malignant tumors resembling the Epstein-Barr virus-associated lymphomas of patients with organ transplants.     

水貂源犬瘟热病毒的分离鉴定

利用Vero传代细胞从病死水貂肝脏中分离获得1株病毒。该毒株可使培养细胞出现明显的细胞病变(CPE)。以提取病毒感染细胞总RNA为模板进行反转录聚合酶链式反应(RT-PCR),结果扩增出的基因片段大小与预期值相符。根据病毒的致细胞病变特征和RT-PCR鉴定结果,确证该毒株为犬瘟热病毒。