抗癌药对黑胸大蠊淋巴细胞和生殖细胞核结构的损伤

噻替派浓度为0.1%、0.3%、0.5%时,黑胸大蠊精母细胞染色体断裂和裂隙率分别为6.3%、 10.5%和14.2%,显著地高于对卵母细胞的影响;和雄虫外周血淋巴细胞微核率呈平行关系,随微核率增多而增加。5-氟尿嘧啶浓度为0.1%、0.3%和0.5%时,卵母细胞染色体断裂和裂隙率分别为3.5%、9.8%和16.2%,和雌虫外周血淋巴细胞微核率呈平行关系,随微核率增多而增加,而对雄虫生殖细胞影响不显著。 Abstract:0.1%,0.3%,0.5% Thio-TEPA induced 6.3%,10.5% and 14.2% chromosome break or gap in spermatocyte of cockroach respectively.This was markedly higher than those in oocyte.In doses from 0.1 to 0.5 Tho-TEPA the frequency of micronucleus increased parallely with nuclear damage.0.1%,0.3%,0.5% 5-fluorouracil induced 3.5%,9.8%,16.2% chromosome break or gap in oocytes respectively.This was paralled with the frequency of micronucleus in lymphocytes of the female.5-fluorouracil showed not marked effect on spermatocyte.     

Cellobiose-oxidizing enzyme from a newly isolated cellulolytic bacterium Cytophaga sp. LX-7

Summary The cellobiose oxidizing enzyme of the newly isolated cellulolytic bacterium Cytophaga sp. LX-7 was produced extracellularly when grown on cellulose or other saccharides, which was previously noted only in fungi. The enzyme could use not only cellobiose, maltose, glucose and other saccharides but also cellulose as substrates, and use dichlorophenol indophenol and oxygen as electron acceptors.     

Bioavailability of organic and inorganic phosphates adsorbed on short-range ordered aluminum precipitate

A nonreductive community-level study of P availability was conducted using various forms of adsorbed P. Orthophosphate (Pi), inositol hexaphosphate (IHP), and glucose 6-phosphate (G6P) were adsorbed to a short-range ordered Al precipitate. These bound phosphates provided a P source sufficient to support the growth of microbial communities from acidic Brazilian soils (oxisols). Adsorbed IHP, the most abundant form of organic phosphate in most soils, had the lowest bioavailability among the three phosphates studied. Adsorbed G6P and Pi were almost equally available. The amount of adsorbed Pi (1 cmol P kg^–1) required to support microbial growth was at least 30 times less than that of IHP (30 cmol P kg^–1). With increased surface coverage, adsorbed IHP became more bioavailable. This availability was attributed to a change in the structure of surface complexes and presumably resulted from the decreased number of high-affinity surface sites remaining at high levels of coverage. It thus appears that the bioavailability of various forms of adsorbed phosphate was determined primarily by the stability of the phosphate-surface complexes that they formed, rather than by the total amount of phosphate adsorbed. IHP, having the potential to form stable multiple-ring complexes, had the highest surface affinity and the lowest bioavailability. Bioaggregates consisting of bacteria and Al precipitate were observed and may be necessary for effective release of adsorbed P. Bacteria in the genera Enterobacter and Pseudomonas were the predominate organisms selected during these P-limited enrichments. Correspondence to: C. Shang     

Toxicity to alveolar macrophages in rats following parenteral injection of mercuric chloride

Alveolar macrophages collected by pulmonary lavage from male Fisher-344 rats at intervals (24–72 h) after HgCl₂ injection (1–5 mg/kg, sc) were analyzed by several techniques. Within 24–72 h, the macrophages showed morphological signs of activation (hypertrophy and ruffled plasma membrane). Lipid peroxidation (increased malondialdehyde concentration) was not detected until 48 h. Dose- and time-related effects of HgCl₂ on malondialdehyde concentration and time-related effects of HgCl₂ on malondialdehyde concentration and mercury content of alveolar macrophages were observed 24–72 h postinjection. Diminished cell viability occurred only at 72 h after the highest dosage of HgCl₂. This study demonstrates that the alveolar macrophage was a cellular target for mercury toxicity following parenteral exposure to HgCl₂.     

鲇鱼成鱼和幼鱼中含色素的巨噬细胞集结的诱导发生

通过腹腔注射不同剂量的牛血清白蛋白（ＢＳＡ）或墨汁以刺激巨噬细胞活动,研究了鲇鱼成鱼和幼鱼头肾、肾、脾和肝中含色素的巨噬细胞集结（ＰＭＡ）的发生。鲇鱼淋巴样组织中存在巨噬细胞的不均一性,可分网状／纤维状巨噬细胞,梭状巨噬细胞,圆形红色巨噬细胞,圆形黄红色巨噬细胞和含色素的巨噬细胞。注射ＢＳＡ或墨汁后,头肾、肾,脾和肝中ＰＭＡ和圆形巨噬细胞的数量最终均有不同程度的增加。通过诱导发生实验,表明含色素的     

The cell death inhibitor Bcl-2 and its homologues influence control of cell cycle entry.

The effect of the cell death inhibitor Bcl-2 and its homologues on cell cycle regulation was explored in lymphocytes and cell lines. Expression of a bcl-2 transgene reduced proliferation of thymocytes and delayed cell cycle entry of mitogen-stimulated B and T lymphocytes. Overexpression of Bcl-2, Bcl-xL or adenovirus E1B19kD substantially delayed serum stimulation-induced S phase entry of quiescent NIH 3T3 fibroblasts. Bcl-2-mediated cell survival and growth inhibition are both antagonized by Bax. Bcl-2, Bcl-xL and E1B19kD, but not Bcl-2 mutants that are defective in blocking apoptosis, suppress growth of colon carcinoma cells. This evidence that regulation of cell survival is coupled to control of cell growth has implications for normal cell turnover and tumorigenesis.     

组织型纤溶酶原激活剂（t—PA）工程细胞系遗传特性及成瘤性分析

组织型纤溶酶原激活剂(t-PA)因其在防止血栓形成中起重要作用而受到人们的重视。但由于t-PA在血液中半衰期很短,作为溶栓药,一时难于推广。为了延长半衰期、增强其特异活性,本组构建了t-PA突变体并在CHO-dhfr~-细胞中获得了高效表达。我们在细胞培养基中加入秋水仙素,通过低张、固定、染色,进行染色体分析,结果表明,t-PA工程细胞系染色体条数为20条,畸变类型有异着丝粒。四倍体、裂隙、断片,畸变率为15％,属于正常范围。同时我们对该细胞系进行成瘤性试验,选用4周龄裸鼠作为试验鼠,以Hela细胞为阳性对照,CHO-dhfr~-细胞为阴性对照,试验表明:t-PA工程细胞及表达产物对裸鼠均无成瘤性。     

RFLP mapping of QTLs for yield and related characters in rice (Oryza sativa L.)

Quantitative triat loci (QTLs) for yield and related traits in rice were mapped based on RFLP maps from two indica/indica F₂ populations, Tesanai 2/CB and Waiyin 2/CB. In Tesanai 2/CB, 14 intervals carrying QTLs for eight traits were detected, including 3 for grain weight per plant (GWT), 2 for number of panicles per plant (NP), 2 for number of grains per panicle (NG), 1 for total number of spikelets per panicle (TNS), 1 for spikelet fertility (SF), 3 for 1000-grain weight (TGWT), 1 for spikelet density (SD), and 1 for number of first branches per main panicle. The 3 QTLs for GWT were located on chromosomes 1, 2, and 4, with 1 in each chromosome. The additive effect of the single locus ranged from 2.0 g to 9.1 g. A major gene (np4) for NP was detected on chromosome 4 within the interval of RG143–RG214, about 4cM for RG143, and this locus explained 26.1% of the observed phenotypic variance for NP. The paternal allele of this locus was responsible for reduced panicles per plant (3 panicles per plant). In another population, Waiyin 2/CB, 12 intervals containing QTLs for six of the above-mentioned traits were detected, including 3 for GWT, 2 for each of NP, TNS, TGWT and SD, 1 for SF. Three QTLs for GWT were located on chromosome 1, 4, and 5, respectively. The additive effect of the single locus for GWT ranged from 6.7 g to 8.8 g, while the dominance effect was 1.7–11.5 g. QTL mapping in two populations with a common male parent is compared and discussed.     

Isolation and identification of a non-specific tandemly repeated DNA sequence in Oryza species

A tandemly repeated DNA sequence (RRS7) was isolated from Oryza alta (CCDD). RRS7-related sequences were also found tandemly arrayed in genomes AA, BB, BBCC, CC, and EE, and a small amount of RRS7-related sequences were detected in genome FF and the Oryza species with unknown genomes. DNA sequence analysis of the 1844-bp insert of RRS7 revealed that it contained six tandemly repeated units, of which five were 155 bp in length and one was 194 bp in length and contained an imperfect internal 39-bp duplication. Southern blot analysis showed that the boundary sequence contained in RRS7 is a single-copy sequence. A 155-bp consensus sequence derived from the six monomeric repeats contained no internal repeat and showed no significant homology to other currently known sequences. The results of Southern blot and sequence analysis revealed that there are at least two subfamilies present in the RRS7 family; these are represented by the DraI site and the MspI site, respectively. Restriction digestion with two pairs of isoschizomers MboI/Sau3A and MspI/HpaII demonstrated that most of the C residues in the GATC sites and the internal C in the CCGG sites of the RRS7 family in O. Alta were methylated. The usefulness of the RRS7 family in determining the evolutionary relationship of the genome DD and other Oryza genomes is discussed.