Genotypic control of the speed of development inArabidopsis thaliana (L.)Heynh. lines obtained from natural populations

Sixteen early, medium late, and late homozygote lines ofArabidopsis thaliana, obtained from three natural populations, were crossed with a common check variety S 96. The speed of development was expressed by the value log (x+y), wherex stands for the number of days after which flower primordia appear, andy for the number of leaves in the rosette. The experiments were caried out under conditions which emphasized the differences in the speed of development. We assessed the degree of dominancy, heritability on the basis of F₁ and F₂ variance, and analyzed F₂ distributions. It was established that some of the investigated lines differ from the variety S 96 in one pair of dominant genes or genes with incomplete dominancy for late flowering, other in two pairs of genes with complementary effects, and that the variety S 96 probably also contains other alleles causing late flowering inhibited by some type of epistasis. Even though the most important part is always played by one or two pairs of genes with high dfficiency, genes with lower efficiency often take part in the process; in some lines the genes with high efficiency could not be established.     

Degradation of hyaluronan by ultrasonication in comparison to microwave and conventional heating

Hyaluronan (hyaluronic acid, HA) was depolymerised by ultrasonication (US), microwave irradiation (MW) and conventional heating (CH), and the effect of pH and oxidants was investigated. The degradation was followed by viscometry and size exclusion chromatography coupled with low-angle light scattering. The results demonstrated that depolymerisation of HA by US leveled off to a limiting molecular mass, and the degradation was significantly enhanced by acidic and alkaline pH only in the presence of oxidants. In contrast to US, the course of depolymerisation by MW was strongly pH-dependent, and the degradation rate increased with decreasing pH. The expected enhancement of depolymerisation by MW in comparison to CH was marked only at very short heating time at pH <4. The NMR and FTIR spectral analyses indicated that HA in the whole M_w-range studied retained almost the backbone of the parent polysaccharide independently on the degradation method used. At harsh degradation conditions (long-term treatments, particularly at acidic pH or alkaline pH and in presence of oxidants) the depolymerisation was accompanied by destruction of both constituent sugar residues and formation of unsaturated structures detectable by UV-absorption at 230–240 and 260–270 nm. US-assisted oxidative degradation under mild reaction conditions was shown to be the most appropriate procedure to reduce the molecular mass of HA to 100 kDa without significant chemical modification of the polysaccharide.     

Correlation of cardio-ankle vascular index, ten-year risk assessment and other atherosclerosis risk factors

The aim of the study was to assess correlation of atherosclerosis severity as determined by two different methods of screening for atherosclerosis: (A) measurement of the cardio-ankle vascular index-CAVI by use of the VaseraVS-1500 vascular screening device, and (B) Framingham scale scoring. 52 subjects (28 male and 24 female) were enrolled in the study. Classification of study subjects into four quartiles based on theoretically calculated 10-year risk according to Framingham scale (medians: 1%, 3%, 4% and 15%) confirmed the risk increase to be associated with a statistically significant increase in CAVI, age and total cholesterol, and a statistically significant decrease in HDL-cholesterol (p < 0.001 all). Spearman correlation coefficients showed a statistically significant correlation of 10-year risk with CAVI (p = 0.0242; r = 0.4494). Study results suggested that simultaneous determination of CAVI and 10-year risk might prove justified. They are not contradictory, the more so, these two parameters showed a significant positive correlation. This test panel yields comprehensible, implying all the possible consequences and highly motivating information that may stimulate the person for lifestyle modification.     

Indicative value ofPediastrum and other coccal green algae in palaeoecology

Sporopollenin layers in the cell wall of coccal green algae are responsible for the resistance of cell walls to destructive processes during fossilization as well as during chemical preparation of samples for pollen-analysis. Pollen slides of samples from limnic sediments thus also contain some algal cell walls. Although some pollen-analysts tried to stress this fact, the finds of algae in pollen slides have not been paid systematic attention yet, despite their potential use for a more accurate palaeoecological reconstruction. The article summarizes the results of palaeoecological studies showing how the algae can be used in palaeoecological reconstruction of past environments. The possibility of utilizing the indicative value of algal finds is demonstrated on examples of algal communities from fossil, subrecent and recent sediments from different longitudes, latitudes, and altitudes. The identification and indicative values of species and varieties ofPediastrum are included in a special review (Komárek &; Jankovská, Biblioth. Phycol., in press). The contemporary knowledge of ecological requirements of the given taxa, completed by information from their fossil finds, makes possible the reconstruction of trophic and temperature conditions and of the purity of the water environment of the past water biotopes.     

Efficacy of 6-amino-2-n-pentylthiobenzothiazole onTrichophyton in vitro and in vivo

In vitro and in vivo antifungal activities of synthetically parepared 6-animo-2-n-pentylthiobenzothiazole (APB) againstTrichophyton strains were studied. APB inhibited the growth of 3Trichophyton strains at 65 µg/ml. 2-Mercaptobenzothiazole was not effective at 125 µg/ml and ketoconazole inhibited the growth at 20–30 µg/ml. Treatment of experimental dermatophytosis in guinea pigs using 2.5% APB cream was studied in comparison to Canesten cream (1% clotrimazole). Dermatophytosis was considerably reduced after both APB and Canesten therapies.     

Notes on the relationship between the permeability and viability of yeast cells

При инкубации с дeзоксихолатом клeтки дрожжeи станонятся проницаeмыми для соKeй янтарной кислоты и для фeррицианида. Чeрeз нeкотороe врeмя млeтки погибают и окрашиваютсн основными краситeлями. Так как коррeлпции мeжду проницаeмостью и окрашиваeмкстью клeток нe наблюдалось, высказываeтся врeдположeниe, что при частичном разрушeнии барьeра проницаeмости клeтки в тeчeниe нeкоторого врeмeни могут оставаться живыми.     

Prevalence of chlamydial genital infection and associated risk factors in adolescent females at an urban reproductive health care center in Croatia

The study was undertaken to determine the prevalence of chlamydial genital infection in sexually active, urban adolescent females 15-19 years; to identify behavioral, demographic, and clinical factors associated with chlamydial infections; and to develop criteria for potential screening strategies. 500 adolescent women, median age 17.7 years, who visited gynecological outpatient clinic in Children's Hospital Zagreb for different reasons were enrolled in this study. Gynecological exam, colposcopy, detection of chlamydial infection by the rapid direct immunoassay of endocervical swab (Clearview Chlamydia-Unipath), endocervical cytological examination--Papanicolaou smear, and questionnaire to obtain demographic, social, behavioral and presence of symptoms data were performed. Positive Chlamydia trachomatis test were found in 16.4% of participants, cytologic cervical abnormalities--cervical intraepithelial neoplasia (CIN I-CIN III) were found in 25.2% and cytological signs of Human papilloma virus were found in 11.4%. Stepwise multivariate logistic regression analysis identified five factors associated with infection: the age of menarche < or =13 years, > or =4 lifetime sexual partners, non-use of contraception (rare or never), cervical friability, and abnormal Papanicolaou test. Urban adolescent sexually active women are at high risk for chlamydial infection and other sexually transmitted diseases including HIV infection. Association between chlamydial genital infection and risk-taking sexual and contraceptive behavior was found. Routine Chlamydia trachomatis testing for this population is recommended as well as implementation of school based sexual health education because of their risk-taking sexual behavior.