Expression of HLA-DR antigens on tumour cells does not contribute to skin reactivity to autologous cholesteryl hemisuccinate (CHS)-treated tumour cells in patients with metastatic melanoma

Summary Skin tests with autologous cholesteryl hemisuccinate (CHS)-treated and untreated cells were performed in ten metastatic melanoma patients. In the majority of cases evident reaction was noted with CHS-treated cells (9/10) while the reaction with untreated cells was mostly negative (7/10). Tumour cell suspensions used for skin tests were characterized for reactivity with monoclonal antibody TAL 1B5 detecting the HLA-DR alpha chain. There were no differences between CHS-treated and untreated cells with respect to HLA-DR expression and no correlation was found between grade of skin reaction to CHS-treated cells and the proportion of HLA-DR positive cells in the injected cell sample.     

Elicitors of defence responses repress a gibberellin signalling pathway in barley embryos

Elicitors of defence response can modulate pathways other than those related to pathogen attacks. In this paper, we demonstrate that, as with sugars, chitosan and oligogalacturonides (OGs) can repress the gibberellin signalling pathway leading to the induction of -amylase in barley embryos. These results are suggestive of a complex cross-talk between the defence, hormonal and metabolic signalling pathways.     

Studies of the Stability of Microbial Association Use in Industrial Biofiltering of Gaseous Discharges

Results of industrial exploitation of a biofiltration plant tailored for purifying gaseous discharges of hazardous organic components such as toluene, cyclohexane, and xylene, are examined. Both numerical and compositional variations were monitored for a long-term (more than 1.5 years) utilization process in an association of microorganisms decomposing organic pollutants. A population of microbial association composed by one yeast and two bacterial strains in the biofilm on the surface of filtering sheets was abundant (10⁸–10⁹ yeast cells/cm² and 10¹⁰–10¹¹ bacterial cells/cm²) and stable during the whole period of monitoring. A microbial association in the culture medium averaging 10⁶ yeast cells/l and 10⁸ bacterial cells/l is more susceptible to technogenic impacts and seasonal fluctuations. Overall, the biofilter as an open and autonomic system maintained its microbial association, thereby providing high-degree (93–98%) purification of industrial gaseous discharges from organic pollutants.     

The bacteriophage T4 gene for the small subunit of ribonucleotide reductase contains an intron.

The bacteriophage T4 gene nrdB codes for the small subunit of the enzyme ribonucleotide reductase. The T4 nrdB gene was localized between 136.1 kb and 137.8 kb in the T4 genetic map according to the deduced structural homology of the protein to the amino acid sequence of its bacterial counterpart, the B2 subunit of Escherichia coli. This positions the C-terminal end of the T4 nrdB gene approximately 2 kb closer to the T4 gene 63 than earlier anticipated from genetic recombinational analyses. The most surprising feature of the T4 nrdB gene is the presence of an approximately 625 bp intron which divides the structural gene into two parts. This is the second example of a prokaryotic structural gene with an intron. The first prokaryotic intron was reported in the nearby td gene, coding for the bacteriophage T4-specific thymidylate synthase enzyme. The nucleotide sequence at the exon-intron junctions of the T4 nrdB gene is similar to that of the junctions of the T4 td gene: the anticipated exon-intron boundary at the donor site ends with a TAA stop codon and there is an ATG start codon at the putative downstream intron-exon boundary of the acceptor site. In the course of this work the denA gene of T4 (endonuclease II) was also located.     

Alterations in sex steroid-binding protein (SBP), corticosteroid-binding globulin (CBG), and steroid hormone concentrations during pregnancy in rhesus macaques

Temporal relationships between concentrations of sex steroid-binding protein (SBP), corticosteroid-binding globulin (CBG), total and free estradiol, total and free testosterone, cortisol, and progesterone were studied in plasma obtained at 1- to 3-day intervals throughout gestation in six rhesus macaques. Concentrations of SBP and CBG were measured by diethylaminoethyl cellulose filter assays. Total and free steroids were estimated by radioimmunoassay and ultrafiltration dialysis, respectively. We found that SBP was elevated between days 30 and 50 and CBG between days 60 and 140; both then declined until term (167 days). Estradiol increased gradually throughout gestation. Testosterone was elevated between days 10 and 40, then declined, and rose slightly in late gestation until approximately 15 days before delivery, when it increased markedly. Free estradiol and testosterone increased dramatically before parturition. Progesterone was elevated between days 25 and 45 and declined to relatively constant levels thereafter. Cortisol was essentially unchanged throughout gestation. Our data show that in the pregnant rhesus, levels of SBP and CBG vary independently of one another, but both decline before term; concentrations of both total and free estradiol and testosterone increase markedly before parturition; in late gestation, elevated estrogen is not associated with increased levels of SBP or CBG (as it is in human females).     

Studies on the phospholipid composition of pathogenic cell membranes of Mycoplasma hyopneumoniae

The membrane phospholipid and fatty acid compositions of Mycoplasma hyopneumoniae, a pathogen of porcine enzootic pneumoniae isolated in China, was studied by thin-layer chromatography and gas chromatography. The results showed that membrane phospholipids consisted predominantly of diphosphatidylglycerol. The percentage of C16 - C18 fatty acids comprised 79% of the total fatty acids, of which oleic acid as well as palmitic acid are the major fatty acids. Some differences were shown in fatty acid composition as compared with membranes of other species of Mycoplasma.     

A protein tyrosine phosphatase inhibitor, sodium orthovanadate, causes parthenogenetic activation of pig oocytes via an increase in protein tyrosine kinase activity.

This study was conducted to determine whether a protein tyrosine kinase (PTK) activity is involved in the initiation of the events that occur at fertilization in pig oocytes. After maturation for 47 h, a 7-h treatment of oocytes with 1 mM sodium orthovanadate, which is an inhibitor of protein tyrosine phosphatase, caused more than 90% pronuclear formation, cortical granule exocytosis, and a decrease in mitogen-activated protein kinase activity. Immunoblotting with an antibody specific for phosphotyrosine showed at least three proteins whose phosphotyrosine contents were significantly increased upon treatment of oocytes with 1 mM sodium orthovanadate. Preincubation of pig oocytes with 50 microM tyrphostin 47, a specific PTK inhibitor, completely blocked the ability of sodium orthovanadate to trigger activation events. In addition, when oocytes were pretreated with the calcium-chelating agent BAPTA-AM, sodium orthovanadate-stimulated pronuclear formation was significantly (P < 0.01) reduced (94.0% vs. 43.1%). These results suggest that PTK may be involved in pig oocyte activation in a calcium-dependent manner and that the stimulation of tyrosine kinase is able to signal a series of intracellular changes that lead to the activation events associated with fertilization.     

低分子抑瘤物净化白血病细胞的实验研究及临床应用

胎儿肝脏中存在一类小分子量（分子量〈１０ｋＤ）的肿瘤抑制物,其在体外对ＨＬ－６０等多种白血病细胞系具有明显的选择性抑制作用,对急性白血病患者骨髓的白血病祖细胞也具有这种选择性抑制效果;分离纯化获得两种天然低分子抑瘤物（７－ＫＣ和７－β－ＨＣ）和一种外源性低分子抑瘤物（ＤＢＰ）,研究证实其抑制白血病细胞生长的作用机制是诱导白血病细胞凋亡;将其应用于白血病及恶性淋巴瘤自体骨髓移植时的体外净化,完成１２     

Farmers’ genetic perceptions regarding their crop populations: An example with maize in the central valleys of Oaxaca, Mexico

Collaborative plant breeding is an approach to crop improvement that includes close attention to specific adaptation and interaction between farmers and formal plant breeders to better meet the needs of those farmers. Collegial interaction capable of making best use of the knowledge and skills of farmers and breeders will depend upon an understanding of those in terms that are relevant to each. To facilitate this interaction with the goal of making farmer selection practices more effective, the work described here sought to improve outside researchers’ understanding of farmers’ fundamental perceptions about their populations, growing environments, and expectations for response to selection. Various methods were used to accomplish this with a small sample of maize farmers in two communities in the Central Valleys of Oaxaca, Mexico. Farmers’ decisions about maize varietal type repertoires imply assessments based on genetic and environmental variation in the local context. A clear distinction was made between traits of high and low heritability and expected response to selection, however, some traits of interest to farmers such as large seed size may involve considerations other than their potential for expression in the progeny generation.     

The design and synthesis of purine inhibitors of CDK2. III

Cyclin-dependent kinases (CDKs) belong to a class of enzymes that control the ability of a cell to enter into and proceed through the cell division cycle. Using purine as a scaffold, we have synthesized a number of nanomolar inhibitors of CDK-2/cyclin E. In this report, the synthesis of a series of piperidine-substituted purine analogs will be presented, as well as some of their in vitro and in vivo biological effects.