Apoptosis and nutrition: Involvement of amino acid transport system in repression of hybridoma cell death

Mouse hybridoma cells cultured on the verge of starvation-induced apoptosis, i.e. in a medium diluted with saline, proved to serve as a sensitive screening system for apoptosis-suppressing activity of nutrient medium components. Conventional amino acid mixtures were found to suppress the starvation-induced apoptosis, whereas a vitamin mixture was ineffective. (Frank F (1995) Biotechnol. Bioeng. 45: 86–90). Recent experiments showed that suppression of apoptosis, and concurrent resumption of growth, could be achieved by addition of single substances at millimolar concentrations. The set of active substances included certain coded L-amino acids (glycine, alanine, serine, threonine, proline, asparagine, glutamine, histidine), non-coded amino acids (-alanine, taurine, 4-aminobutyric acid), and a non-metabolizable analogue (2-aminoisobutyric acid). This finding shows that some amino acids do not act solely as nutrients, but also as specific signal molecules. The specificity of the effect points to the involvement of adaptively regulated amino acid transport systems A and N in maintaining the balance between triggering and suppression of starvation-induced apoptosis.     

Photo-CIDNP study of the interaction between the glucocorticoid receptor DNA-binding domain and glucocorticoid response elements

Summary Photo-CIDNP studies were performed on two protein fragments that both contain the double zinc-finger DNA-binding domain of the glucocorticoid receptor. In the absence of DNA, Tyr⁴⁵² and Tyr⁴⁷⁴ are polarised in both fragments while Tyr⁴⁹⁷ is not. Addition of a palindromic glucocorticoid response element (GRE) results in the suppression of Tyr⁴⁷⁴ polarization while the polarization of Tyr⁴⁵² is unaffected. The same result is observed upon adding a half GRE to the protein fragment indicating that the suppression of Tyr⁴⁷⁴ polarization is not due to protein-protein contacts but to interaction with DNA.     

Local and systemic antibody response in infants after oral administration of inactivated enteropathogenicE. coli serotype O111 and O55

In ten infants divided into two groups (up to one month of age and at 2–7 months of age) the dynamics and formation of different antibody isotypes produced locally in the intenstine and in serum after orally administered inactivated enteropathogenicE. coli strains O111 and O55 was followed during 30 d after the first and booster dose by using an indirect immunofluorescence method. Infants up to one month of age produced antibodies of IgM isotype in stool together with the IgA isotype after the first and booster dose of the vaccine against both antigens. Serum IgG antibody increased after 2 d following the first and second dose of antigens and remained higher during 5 d. The infants aged 2–7 months expressed predominantly the IgA isotype response in stool after the first and booster dose of antigens. The serum immunoglobulin levels did not change after oral antigen administration.     

Cytotoxic activities of Hypericum perforatum L. extracts against 2D and 3D cancer cell models

Cytotechnology - Six extracts were obtained from plant species Hypericum perforatum L., collected at Samsun in Turkey. The aim of this study was to examine the mechanisms of the anticancer activity...     

Indirect Immunofluorescence Assay for the Simultaneous Detection of Antibodies against Clinically Important Old and New World Hantaviruses

In order to detect serum antibodies against clinically important Old and New World hantaviruses simultaneously, multiparametric indirect immunofluorescence assays (IFAs) based on biochip mosaics were developed. Each of the mosaic substrates consisted of cells infected with one of the virus types Hantaan (HTNV), Puumala (PUUV), Seoul (SEOV), Saaremaa (SAAV), Dobrava (DOBV), Sin Nombre (SNV) or Andes (ANDV). For assay evaluation, serum IgG and IgM antibodies were analyzed using 184 laboratory-confirmed hantavirus-positive sera collected at six diagnostic centers from patients actively or previously infected with the following hantavirus serotypes: PUUV (Finland, n = 97); SEOV (China, n = 5); DOBV (Romania, n = 7); SNV (Canada, n = 23); ANDV (Argentina and Chile, n = 52). The control panel comprised 89 sera from healthy blood donors. According to the reference tests, all 184 patient samples were seropositive for hantavirus-specific IgG (n = 177; 96%) and/or IgM (n = 131; 72%), while all control samples were tested negative. In the multiparametric IFA applied in this study, 183 (99%) of the patient sera were IgG and 131 (71%) IgM positive (accordance with the reference tests: IgG, 96%; IgM, 93%). Overall IFA sensitivity for combined IgG and IgM analysis amounted to 100% for all serotypes, except for SNV (96%). Of the 89 control sera, 2 (2%) showed IgG reactivity against the HTNV substrate, but not against any other hantavirus. Due to the high cross-reactivity of hantaviral nucleocapsid proteins, endpoint titrations were conducted, allowing serotype determination in >90% of PUUV- and ANDV-infected patients. Thus, multiparametric IFA enables highly sensitive and specific serological diagnosis of hantavirus infections and can be used to differentiate PUUV and ANDV infection from infections with Murinae-borne hantaviruses (e.g. DOBV and SEOV).     

Biosystematics of Gracilaria foliifera (Gigarthales, Rhodophyta)

Strains of Gracilaria foliifera (Forsskål) Børgesen isolated into culture from Ireland (where the species would appear to be introduced), England and the Atlantic coast of France were interfertile. Strains of G. foliifera from Texas and North Carolina, U.S.A. were similarly interfertile but did not cross with the European strains. The North Carolina strain was distinctly flattened in culture and superficially resembled G. foliifera from Europe whereas the Texas strain was terete or slightly flattened. Both of the American strains were interfertile with an isolate of G. tikvahiae McLa-chlan from the type locality of this species in northern Nova Scotia, Canada. It seems likely from these data that G. foliifera is not represented on the coast of North America and that G. tikvahiae is a highly morphologically variable species widely distributed from Nova Scotia south to the Caribbean. Examination of type material of Gracilaria foliifera and G. multipartita (Clemente) Harvey, together with phyto-geographical considerations, suggests that the species known as G. foliifera on eastem Atlantic masts should be known as G. rnultipartita , and that G. foliifera s. str . is probably confined to the Red, Arabian, and Indian Seas.     

Efficient Haploid Induction in Microspore Suspension Culture of Aesculus hippocastanum and Karyotype Analysis

Suspension culture was more efficient method for haploid production than anther culture. All analysed androgenic regenerants originating from embryogenic microspores in suspension culture of Aesculus hippocastanum L. had a haploid number of chromosomes (n=20), while 50 % of those derived from anther culture were diploids. This revised version was published online in July 2006 with corrections to the Cover Date.     

Caffeine induces a second wave of apoptosis after low dose-rate gamma radiation of HL-60 cells

Most cell lines that lack functional p53 protein are arrested in the G₂ phase of the cell cycle due to DNA damage. It was previously found that the human promyelocyte leukemia cells HL-60 (TP53 negative) that had been exposed to ionizing radiation at doses up to 10 Gy were arrested in the G₂ phase for a period of 24 h. The radioresistance of HL-60 cells that were exposed to low dose-rate gamma irradiation of 3.9 mGy/min, which resulted in a pronounced accumulation of the cells in the G₂ phase during the exposure period, increased compared with the radioresistance of cells that were exposed to a high dose-rate gamma irradiation of 0.6 Gy/min. The D₀ value (i.e. the radiation dose leading to 37% cell survival) for low dose-rate radiation was 3.7 Gy and for high dose-rate radiation 2.2 Gy. In this study, prevention of G₂ phase arrest by caffeine (2 mM) and irradiation of cells with low dose-rate irradiation in all phases of the cell cycle proved to cause radiosensitization (D₀=2.2 Gy). The irradiation in the presence of caffeine resulted in a second wave of apoptosis on days 5–7post-irradiation. Caffeine-induced apoptosis occurring later than day 7 post-irradiation is postulated to be a result of unscheduled DNA replication and cell cycle progress.     

槭属的系统演化与地理分布

槭属（Acer L．）属槭树科（Aceraceae）,200种,分布于亚、欧、北美和非洲北缘。本文研究了槭属的系统演化、地理分布、起源与扩散。认为：（1）槭树科与无患于科关系密切,槭属是槭树科2属中较进化的类群。（2）在原始而典型的槭属植物的基础上,槭属沿花的各部减少,有的器官甚至向完全退化的方向演化,但也有少数向增加数目的方向特化。（3）讨论了槭属4亚属23组的演化趋势,并绘制出其系统演化图。（4）槭属起源于侏罗纪的中国四川东部、湖北、湖南及其邻近地区,并向西、东北和南方扩散而进入西亚、欧洲、非洲北缘、北美洲和马来半岛至印尼。