[Homology-dependent inactivation of LTR retrotransposons in genomes of Aspergillus fumigatus and A. nidulans].

Repeat-induced point mutation (RIP) is the most intriguing among the known mechanisms of repeated sequences inactivation because of its ability to produce irreversible mutation of repeated DNA. Discovered for the first time in Neurospora crassa, RIP is characterized by C:G to T:A transitions in duplicated sequences. The mechanisms and distribution of RIP are still purely investigated. Mobile elements are a common target for the processes which lead to homology-dependent silencing because of their ability to propagate themselves. We have done comparative analysis of LTR retrotransposons in genomic scale from genomes of two aspergilli fungi--Aspergillus funmigatus and A. nidulans, based on several copies we reconstructed "de-RIP" retroelements. Investigations of frequencies of CpG, CpA and TpG sites, which are potential targets for mutagenesis, showed the much lower frequencies of these sites in mobile elements in comparison with structural genes. LTR retrotransposons from A. fumigatus and A. nidulans have different ratio of types of substitutions. Our analysis indicates that two investigated fungi have or had the RIP-like processes for repeated sequences inactivation, in various modes. Whereas in A. fumigatus the context for mutagenesis consists of both CpG and CpA sites, in A. nidulans inactivation seems to proceed only on CpG dinucleotides. The present investigation gives a theoretical background for planning of experimental studying of RIP inactivation in aspergilli.

[LTR retrotransposons from genomes of Aspergillus fumigatus and A. nidulans].

Fungi Aspergillus spp. are able to infect all tissues and organs and often cause invasive mycosis (aspergillosis), which is usually a fatal disease, especially in the patients with compromised immune system. Microbiological monitoring of these infectious agents is necessary in modem medical facilities. Mobile elements can be used as markers for identification of species and strains of Aspergillus found indoors as well as in aspergillosis diagnostics. Genomic sequences of two representative Aspergillus species, A. fumigatus and A. nidulans, were analysed in silico in order to detect LTR retrotransposons. We found considerable differences in the composition of retrotransposon families between two studied species. One of the detected families, which is present in both studied Aspergillus species, is phylogenetically quite different from all other known fungal retrotransposons. The majority of elements are represented by damaged copies. Nevertheless, we describe for the first time allegedly non-damaged LTR copies that contain intact ORFs and could be active.

Epidemiological and clinical characteristics of scorpionism in Colima, Mexico (2000-2001).

We analyzed 13,223 clinical records of patients treated for scorpion sting in hospitals of the Mexican Institute of Public Health and the Ministry of Health in the state of Colima, Mexico, during the years 2000-2001. A database containing demographic, epidemiological and clinical information was constructed and analyzed retrospectively. Patients were classified in the categories as mild (49.2%), moderate (33.8%) and severe (17.0%) according to commonly accepted standards. Most common symptoms recorded were local pain (94.7%), local paresthesia (67.2%), pruritus/itching (54.3%), sensation of a lump or hair in the throat (47.3%), and sialorrhoea (27.7%). The median time from sting to admission to the emergency room (patient delay) was 33min (interquartile range: 12-60). We found that older and clinically severe patients were significantly associated with longer times of admission to the emergency room. Age was significantly associated with clinical severity: the age group 0-10 years included a higher proportion of severe cases than the group 11 years and older. In four cases, patients died. An educational campaign to inform the population about the importance of receiving prompt attention following a scorpion sting has potential value in reducing complications in the emergency room.

Localization of the mouse gene for secreted phosphoprotein 1 (Spp-1) (2ar, osteopontin, bone sialoprotein 1, 44-kDa bone phosphoprotein, tumor-secreted phosphoprotein) to chromosome 5, closely linked to Ric (Rickettsia resistance).

We have used a cDNA probe for mouse secreted phosphoprotein 1 (Spp-1, also known as 2ar, osteopontin, bone sialoprotein 1, 44-kDa bone phosphotein, tumor-secreted protein) to find a restriction fragment length polymorphism in the gene from C57BL/6J and DBA/2J mice. The strain distribution pattern in 25 BXD recombinant inbred lines is identical with that previously determined for the dominant, autosomal gene, Ricr (Rickettsia resistance). This places Spp-1 on mouse chromosome 5 with a 95% confidence limit of being within 4.32 cM of Ric. Evidence supporting the possibility of allelism between Spp-1 and Ric is briefly discussed.

[Protein factor from regenerating rat liver destabilizing secondary DNA structure]. / Belkovyi faktor iz regeneriruiushchei pecheni krys, destabiliziruiushchii vtorichnuiu strukturu DNK.

In DNA preparations isolated from regenerating rat liver 22 hours after partial hepatectomy, i.e. at the period of the most intensive DNA synthesis a "Denaturating Protein Factor" (DPF) tightly bound to DNA was found. Isolated protein fraction with a molecular weight of 6500 dalton was found to be homogenous upon SDS-polyacrylamide electrophoresis. The degree of destabilisation of DNA was estimated by its reaction with water-soluble [14C]CME-carbodiimide which modifies selectively guanine and thymine residues only in the denatured DNA regions. Pronase treated DPF loses its DNA-denaturing capacity. Pronase treatment of DNA--DPF complex restores native DNA structure. DPF from rat liver was able to denature DNA from calf thymus and bacteriophage T7 DNA. A hypothesis is proposed that the DPF is responsible for the destabilization of DNA secondary structure in the process of replication.