Synthesis of 1-(2-hydroxy-3-methoxypropyl)uracils and their activity against L1210 and macrophage raw 264.7 cells

The title compounds were obtained from appropriate 5-substituted uracil derivatives and 1,2-oxy-3-methoxypropane in the presence of sodium hydride. Under similar conditions 5-iodouracil gave 2-methoxymethyl-2,3-dihydro-oxazolo[3,2-c]pyrimidine-5,7-dione as a result of intramolecular cine type nucleophilic substitution. Cytotoxicity of 1-(2-hydroxy-3-methoxypropyl)-5-substituted uracil derivatives against L1210 and macrophage RAW 264.7 cells in vitro was examined.     

Studies on genetic changes in rye samples (Secale cereale L.) maintained in a seed bank

The aim of this study was to identify genetic changes in rye seeds induced by natural ageing during long-term storage and consecutive regeneration cycles under gene bank conditions. Genomic DNA from four rye samples varying in their initial viability after one and three cycles of reproduction was analyzed by AFLP (amplified fragment length polymorphism) fingerprinting. Seven EcoRI/MseI primer combinations defined 663 fragments, and seven PstI/MseI primer combinations defined 551 fragments. The variation in the frequency of the seventy-four EcoRI/MseI bands was statistically significant between samples. These changes could be attributed to genetic changes occurring during storage and regeneration. However, the PstI/MseI fragments appeared to be uninfluenced by seed ageing, regeneration and propagation. A combined Principle Coordinate Analysis revealed differences between samples with different initial viability. We showed that materials with low initial viability differ in their response from highly viable ones, and that the changes exhibited in the former case are preserved through regeneration cycles.     

A new species of freshwater turbellarian from Africa,predatory on mosquitoes: Mesostoma zariae n. sp. (Typhloplanoida)

A new species of the genus Mesostoma Ehrenberg 1935, M. zariae n.sp. is described and its relationship discussed. The new species belongs to the M. lingua species-group and is characterised by the presence of two kinds of prostate secretions and a pear-shaped penis papilla. It occurs in small standing or slowly running waters at Zaria, Nigeria. It has previously been proven (Mead 1978) that this species is predatory on the aquatic stages of mosquitoes.     

Hypogonadotropic hypogonadism due to GnRH receptor mutation in a sibling

Hypogonadotropic hypogonadism (HH) is characterised by delayed puberty and infertility. Congenital HH comprises Kallmann syndrome with hypo-/anosmia and idiopathic HH (IHH). The genetic origin remains unknown in most cases, but the defective GnRH receptor gene (GNRHR) accounts for a considerable proportion of IHH. Here we describe a pair of siblings diagnosed with IHH. Aged 17 years, the boy was referred because of short stature (162 cm) and overweight (62.5 kg). He presented no signs of puberty, bone age of 14.5 years and insulin resistance. His sister, aged 16 years, also displayed delayed puberty. She was 166 cm tall and weighed 52 kg; her bone age was 12.5 years. Pelvic ultrasonography showed an infantile uterus and fibrous ovaries. In both siblings, serum gonadotropins were extremely low, and non-responsive to GnRH. Testosterone (1.38 nmol/l) and IGF1 (273 ng/ml) were decreased in the boy, although the girl did not present IFG1 deficiency. Her serum oestradiol was 10 pg/ml. MRIs of the hypothalamo-pituitary region and olfactory bulbs revealed them to be normal. The patients' sense of smell was unaltered. Their parents appeared to be first degree cousins. Considering the clinical data and potentially autosomal recessive HH transmission, the GNRHR gene was screened. The siblings turned out to be homozygous for the G416A transition, which had previously been identified in other HH individuals. The parents were heterozygous mutation carriers. The proband, moderately responding to LH, was started on low dose testosterone replacement, and his sister on transdermal oestradiol. Molecular data indicative of GnRH resistance could guide their future therapy should they desire fertility restoration. Further observations of the male patient may provide insights into androgen's influence on body mass, growth and insulin sensitivity.     

Human endogenous retrovirus (HERVK9) structural polymorphism with haplotypic HLA-A allelic associations

The frequency and HLA-A allelic associations of a HERVK9 DNA structural polymorphism located in close proximity to the highly polymorphic HLA-A gene within the major histocompatibility complex (MHC) genomic region were determined in Japanese, African Americans, and Australian Caucasians to better understand its human population evolutionary history. The HERVK9 insertion or deletion was detected as a 3' LTR or a solo LTR, respectively, by separate PCR assays. The average insertion frequency of the HERVK9.HG was significantly different (P < 1.083e(-6)) between the Japanese (0.59) and the African Americans (0.34) or Australian Caucasians (0.37). LD analysis predicted a highly significant (P < 1.0e(-5)) linkage between the HLA-A and HERVK9 alleles, probably as a result of hitchhiking (linkage). Evolutionary time estimates of the solo, 5' and 3' LTR nucleotide sequence divergences suggest that the HERVK9 was inserted 17.3 MYA with the first structural deletion occurring 15.1 MYA. The LTR/HLA-A haplotypes appear to have been formed mostly during the past 3.9 MY. The HERVK9 insertion and deletion, detected by a simple and economical PCR method, is an informative genetic and evolutionary marker for the study of HLA-A haplotype variations, human migration, the origins of contemporary populations, and the possibility of disease associations.     

Jasmonate effects on in vitro tuberization and tuber bulking in two potato cultivars (Solanum tuberosum L.) under different media and photoperiod conditions

Summary Jasmonic acid (JA) effects on in vitro tuberization of potato nodal explants cvs. Sangre and Russet Burbank were tested under liquid and solid media conditions and 0,8, and 16h photoperiod. Explants taken from stock plants grown on 2.5μM JA-supplemented medium tuberized first, particularly in darkness. The most pronounced benefits of the JA pretreatment were recorded under 16h photoperiod, which is known to inhibit tuberization. Cultivar Sangre benefited from the JA preconditioning of stock plants more than Russet Burbank. Russet Burbank required the JA supplement in tuberization media to reach the same degree of stimulation. Overall, microtubers produced either from JA preconditioned stock plants or on the JA-containing tuberization media were more uniform and larger than from other treatments. Eight hours photoperiod was by far the best treatment for the production of high-quality uniform microtubers. JA conditioning of stock plants prior to taking explants for tuberization is being proposed as a treatment enhancing the quality of microtubers.     

Modifications of erythrocyte membrane hydration induced by organic tin compounds

A study on the effects of selected organic chlorides of tin on the extent of hydration of the lipid bilayer of erythrocyte ghosts from pig blood is presented. The following compounds were used, dibutyltin dichloride (DBT), tributyltin chloride (TBT), diphenyltin dichloride (DPhT) and triphenyltin chloride (TPhT). The degree of membrane hydration was measured by the ATR FTIR technique, which makes it possible to estimate the level of carbonyl and phosphate group hydration in lipids of membranes. Other measurements were made with a fluorescence technique involving a laurdan probe. Tin organic compounds caused dehydration of the lipid bilayer of ghosts in the region of the carbonyl groups. DBT and TBT produced weak dehydration in the region of the phosphate group, whereas DPhT and TPhT increased hydration. The results allow one to determine the location of organotin compounds within a membrane, and show that TBT penetrates the membrane the deepest and DBT the shallowest. Phenyl tin compounds penetrate membranes to an intermediate depth. The results obtained indicate that the destructive properties of the organometallic compounds depend mostly on their effect on hydration of the membrane.     

Characterization of member of DUF1888 protein family, self-cleaving and self-assembling endopeptidase

The crystal structure of SO1698 protein from Shewanella oneidensis was determined by a SAD method and refined to 1.57 Å. The structure is a β sandwich that unexpectedly consists of two polypeptides; the N-terminal fragment includes residues 1–116, and the C-terminal one includes residues 117–125. Electron density also displayed the Lys-98 side chain covalently linked to Asp-116. The putative active site residues involved in self-cleavage were identified; point mutants were produced and characterized structurally and in a biochemical assay. Numerical simulations utilizing molecular dynamics and hybrid quantum/classical calculations suggest a mechanism involving activation of a water molecule coordinated by a catalytic aspartic acid.