Intraspecific genetic diversity of Pyrenophora tritici-repentis (Died.) Drechs. (Drechslera tritici-repentis[Died.] Shoem.) detected by random amplified polymorphic DNA assays

Abstract

Random amplified polymorphic DNAs (RAPDs) were used to study the genetic variation of Pyrenophora tritici-repentis isolates causing wheat tan spot. Two independent experiments were conducted in 2002 – 2003. In 2002, 40 isolates collected in Russia (Krasnodar region, Bashkiria), Germany, and the Czech Republic were studied and 35 unique RAPD genotypes were identified. Most of the genetic variation (72%) was observed within populations and 28% between them. In 2003, 69 new isolates from Russia (Dagestan, North Osetia, Bashkiria), Germany, and the Czech Republic were studied and 47 unique RAPD genotypes were identified. As in 2002, most of the genetic variation (75%) was observed within populations and 25% between them. Total gene diversity in each group ranged from 0.67 – 1.00 for 2002 and was 1.00 for 2003. The average gene diversity was estimated between 0.13 and 0.20 in 2002 and between 0.07 and 0.18 in 2003. A dendrogramme based on genetic distances between isolates illustrates that the variation is distributed on a small scale (0.3 – 4.0%). Estimated F_ST values and clustering of isolates on dendrogrammes suggest that groups of isolates from Bashkiria and groups of isolates from Dagestan and North Osetia are separated from others and may be considered as different geographical populations. No clear differentiation between isolates from other sites was revealed.     

A New Aerobic Gram-Positive Bacterium with a Unique Ability to Degrade ortho- and para-chlorinated Biphenyls

Strain B51 capable of degrading polychlorinated biphenyls (PCB) was isolated from soil contaminated with wastes from the chemical industry. Based on its morphological and chemotaxonomic characteristics, the strain was identified as a Microbacterium sp. Experiments with washed cells showed that strain B51 is able to degrade ortho- and para-substituted mono-, di-, and trichlorinated biphenyls (MCB, DCB, and TCB, respectively). Unlike the known PCB degraders, Microbacterium sp. B51 is able to oxidize the ortho-chlorinated ring of 2,2-DCB and 2,4-DCB and the para-chlorinated ring of 4.4-DCB. The degradation of 2,4-DCB and 4,4-DCB was associated with the accumulation of 4-chlorobenzoic acid (4-CBA) in the medium in amounts comprising 80–90% of the theoretical yield. The strain was able to utilize 2-MCB, 2,2-DCB, and their intermediate 2-CBA and to oxidize the mono(ortho)-chlorinated ring of 2,4,2-TCB and the di(ortho-para)-chlorinated ring of 2,4,4-TCB. A mixed culture of Microbacterium sp. B51 and the 4-CBA-degrading bacterium Arthrobacter sp. H5 was found to grow well on 1 g/l 2,4-DCB as the sole source of carbon and energy.     

Some observations on the effect of Daflon (micronized purified flavonoid fraction of Rutaceae aurantiae) in bancroftian filarial lymphoedema

BACKGROUND: Morbidity management is a core component of the global programme for the elimination of lymphatic filariasis. In a double-blind clinical trial, the tolerability and efficacy of Daflon (500 mg) + DEC (25 mg) or DEC (25 mg) alone, twice daily for 90 days, was studied in 26 patients with bancroftian filarial lymphoedema. RESULTS: None of the patients in either drug group reported any adverse reaction throughout the treatment period (90 days). Haematological and biochemical parameters were within normal limits and there was no significant difference between the pre-treatment (day 0) and post-treatment (day 90) values. The group receiving Daflon showed significant reduction in oedema volume from day 90 (140.6 PlusMinus; 18.8 ml) to day 360 (71.8 PlusMinus; 20.7 ml) compared to the pre-treatment (day 0, 198.4 PlusMinus; 16.5 ml) value. This accounted for a 63.8% reduction in oedema volume by day 360 (considering the pre-treatment (day 0) as 100%). In the DEC group, the changes in oedema volume (between day 1 and day 360) were not significant when compared to the pre-treatment (day 0) value. The percentage reduction at day 360 was only 9%, which was not significant (P > 0.05). CONCLUSION: This study has shown that Daflon (500 mg, twice a day for 90 days) is both safe and efficacious in reducing oedema volume in bancroftian filarial lymphoedema. Further clinical trials are essential for strengthening the evidence base on the role of this drug in the morbidity management of lymphatic filariasis.     

Combinations of PARP Inhibitors with Temozolomide Drive PARP1 Trapping and Apoptosis in Ewing’s Sarcoma

Ewing’s sarcoma is a malignant pediatric bone tumor with a poor prognosis for patients with metastatic or recurrent disease. Ewing’s sarcoma cells are acutely hypersensitive to poly (ADP-ribose) polymerase (PARP) inhibition and this is being evaluated in clinical trials, although the mechanism of hypersensitivity has not been directly addressed. PARP inhibitors have efficacy in tumors with BRCA1/2 mutations, which confer deficiency in DNA double-strand break (DSB) repair by homologous recombination (HR). This drives dependence on PARP1/2 due to their function in DNA single-strand break (SSB) repair. PARP inhibitors are also cytotoxic through inhibiting PARP1/2 auto-PARylation, blocking PARP1/2 release from substrate DNA. Here, we show that PARP inhibitor sensitivity in Ewing’s sarcoma cells is not through an apparent defect in DNA repair by HR, but through hypersensitivity to trapped PARP1-DNA complexes. This drives accumulation of DNA damage during replication, ultimately leading to apoptosis. We also show that the activity of PARP inhibitors is potentiated by temozolomide in Ewing’s sarcoma cells and is associated with enhanced trapping of PARP1-DNA complexes. Furthermore, through mining of large-scale drug sensitivity datasets, we identify a subset of glioma, neuroblastoma and melanoma cell lines as hypersensitive to the combination of temozolomide and PARP inhibition, potentially identifying new avenues for therapeutic intervention. These data provide insights into the anti-cancer activity of PARP inhibitors with implications for the design of treatment for Ewing’s sarcoma patients with PARP inhibitors.     

The study of markers of herpes virus infections in myocardial ischemia

A group of patients with ischemic heart disease (IHD), who underwent surgical aorta-coronary vascular shunting, was examined in this investigation. Low titers of HSV-1 specific IgG were detected in all patients, the obtained values being consistent with similar data obtained in healthy subjects of the same age. Negative PCR of HSV-I DNA in blood and biopsy results were obtained. None of the patients demonstrated typical clinical pattern of infectious disease caused by herpes simplex virus. These data are evidence of the absence of the HSV-1 correlation with coronary atherosclerosis in patients with the IHD diagnosis. The significance of HCMV specific IgG titers and HCMV DNA detected in blood plasma in 87.7% cases is probably attributed to existence of connection of HCMV infection markers revealing in patient' blood with IHD diagnosis and coronary atherosclerosis. Besides, the HCMV DNA presence in biopsy taken from myocardium or vascular wall with lesion is revealed in 100% cases. The cytomegalovirus markers in tissue lesions with the help of specific antiserums marked to HSMV recombinant proteins are also revealed in 100% cases. This fact indicates the connection between pathological atherosclerotical process in IHD and cytomegalovirus infection.     

Dependence of the functional capacity of the cardiorespiratory system on the body mass in patients with coronary heart disease

The influence of excessive body mass on the development of cardiorespiratory deficiency was studied in patients with coronary heart disease (CHD). Basic parameters of hemodynamics and gas exchange were measured during a graded exercise test. In the CHD patients with excessive body mass, mean blood pressure, cardiac output, left ventricular power output, and left ventricular posterior wall thickness were significantly increased even at rest. During exercise, these patients displayed an increase in myocardial energy consumption and peripheral vascular resistance. It was concluded that an excess in body mass is critical when the increase in the body mass index (Quetelet’s index) exceeds the norm by 20%.