An anion and small molecule inhibition study of the β-carbonic anhydrase from Staphylococcus aureus

Pathogenic bacteria resistant to most antibiotics, including the methicillin-resistant Staphylococcus aureus (MRSA) represent a serious medical problem. The search for new antiinfectives, possessing a diverse mechanism of action compared to the clinically used antibiotics, has become an attractive research field. S. aureus DNA encodes a β-class carbonic anhydrase, SauBCA. It is a druggable target that can be inhibited by certain aromatic and heterocyclic sulphonamides. Here we investigated inorganic anions and some other small molecules for their inhibition of SauBCA. The halides, nitrite, nitrate, bicarbonate, carbonate, bisulphite, sulphate, stannate, and N,N-diethyldithiocarbamate were submillimolar SauBCA inhibitors with K_Is in the range of 0.26 − 0.91 mM. The most effective inhibitors were sulfamide, sulfamate, phenylboronic acid, and phenylarsonic acid with K_Is of 7 − 43 µM. Several interesting inhibitors detected here may be considered lead compounds for the development of even more effective derivatives, which should be investigated for their bacteriostatic effects.     

Adenoviral expression of 15-lipoxygenase-1 in rabbit aortic endothelium: role in arachidonic acid-induced relaxation

Endothelium-dependent vasorelaxation of the rabbit aorta is mediated by either nitric oxide (NO) or arachidonic acid (AA) metabolites from cyclooxygenase (COX) and 15-lipoxygenase (15-LO) pathways. 15-LO-1 metabolites of AA, 11,12,15-trihydroxyeicosatrienoic acid (THETA), and 15-hydroxy-11,12-epoxyeicosatrienoic acid (HEETA) cause concentration-dependent relaxation. We tested the hypothesis that in the 15-LO pathway of AA metabolism, 15-LO-1 is sufficient and is the rate-limiting step in inducing relaxations in rabbit aorta. Aorta and rabbit aortic endothelial cells were treated with adenoviruses containing human 15-LO-1 cDNA (Ad-15-LO-1) or beta-galactosidase (Ad-beta-Gal). Ad-15-LO-1-transduction increased the expression of a 75-kDa protein corresponding to 15-LO-1, detected by immunoblotting with an anti-human15-LO-1 antibody, and increased the production of HEETA and THETA from [(14)C]AA. Immunohistochemical studies on Ad-15-LO-1-transduced rabbit aorta showed the presence of 15-LO-1 in endothelial cells. Ad-15-LO-1-treated aortic rings showed enhanced relaxation to AA (max 31.7 +/- 3.2%) compared with Ad-beta-Gal-treated (max 12.7 +/- 3.2%) or control nontreated rings (max 13.1 +/- 1.6%) (P < 0.01). The relaxations in Ad-15-LO-1-treated aorta were blocked by the 15-LO inhibitor cinnamyl-3,4-dihydroxy-a-cyanocinnamate. Overexpression of 15-LO-1 in the rabbit aortic endothelium is sufficient to increase the production of the vasodilatory HEETA and THETA and enhance the relaxations to AA. This confirms the role of HEETA and THETA as endothelium-derived relaxing factors.     

Training effects of cross-country skiing and running on maximal aerobic cycle performance and on blood lipids

Two experiments were carried out to compare the cardiorespiratory and metabolic effects of cross-country skiing and running training during two successive winters. Forty-year-old men were randomly assigned into skiing (n = 15 in study 1, n = 16 in study 2), running (n = 16 in study 1 and n = 16 in study 2) and control (n = 17 in study 1 and n = 16 in study 2) groups. Three subjects dropped out of the programme. The training lasted 9-10 weeks with 40-min exercise sessions three times each week. The training intensity was controlled at 75%-85% of the maximal oxygen consumption (VO2max) using portable heart rate metres and the mean heart rate was 156-157 beats.min-1 in the training groups. In the pooled data of the two studies the mean increase in the VO2max (in ml.min-1.kg-1) on a cycle ergometer was 17% for the skiing group, 13% for the running group and 2% for the control group. The increase in VO2max was highly significant in the combined exercise group compared to the control group but did not differ significantly between the skiing and running groups. The fasting serum concentrations of lipoproteins and insulin did not change significantly in any of the groups. These results suggested that training by cross-country skiing and running of the same duration and intensity at each session for 9-10 weeks improved equally the cardiorespiratory fitness of untrained middle-aged men.     

Contagious mucocutaneous dermatitis of the mountain hare (Lepus timidus): pathology and cause

Contagious mucocutaneous dermatitis is a frequently encountered disease of mountain hares (Lepidus timidus) in Finland. We describe the histopathologic changes and propose an etiologic cause for this disorder. Fifty-three cases collected during 1982-2000 were examined histologically. Transmission electron microscopy was performed in one case. In fully developed lesions, keratinocytes in epidermis and follicular infundibula were swollen and contained large eosinophilic intracytoplasmic inclusion bodies with marked reticular and ballooning degeneration. In later stages, there was marked necrosis and ulceration with severe pyogranulomatous and suppurative inflammation. At this stage, no viral inclusions were detectable, but secondary Staphylococcus warnerii infection was present in most cases. In late lesions, there was dermal fibrosis with epidermal hyperplasia. No spiral-shaped bacteria suggesting treponematosis were detected at any stage. Ultrastructurally, swollen epidermal and follicle infundibular cells contained round intracytoplasmic inclusion bodies with a myriad of virions typical of poxvirus with a biconcave nucleocapsid core, two lateral bodies, and a clearly discernible outer lipoprotein capsule. The findings suggest that contagious mucocutaneous dermatitis in mountain hares is a viral disease caused by a poxvirus. The disease is often complicated by secondary bacterial infection, most commonly S. warneri.     

Phylogenetic relationships among genotypes of worldwide collection of spring and winter ryes (Secale cereale L.) determined by RAPD-PCR markers

Genetic similarities among 20 spring and 22 winter accessions of agronomically different ryes from fourteen countries were estimated by employing random amplified polymorphic DNA (RAPD) techniques. Cluster analysis of genetic distance data showed that 42 genotypes were readily classifiable into two main groups: spring and winter groups. Within the spring group, cultivars fell into a North European and an American-Chinese group. Cultivars of winter rye fell into four groups: Northern European, Russian, American and Chinese lines. A UPGMA-dendrogram based on genetic distances of cultivars of rye within the winter and spring groups showed that the clusters corresponded well to their geographical locations. The results indicated that isolation has played an important role in the evolution of rye, and that temporal isolation has influenced the genetic diversity of rye more than geographical isolation. In this experiment, RAPD proved to be a rapid, reliable and practicable method of revealing polymorphisms in rye populations.     

First evidence of polyploidy in Psylloidea (Homoptera,Sternorrhyncha): a parthenogenetic population of <Emphasis Type="Italic">Cacopsylla myrtilli</Emphasis> (W. Wagner, 1947) from northeast Finland is apomictic and triploid

This paper reports results of the first cytogenetic study of parthenogenetic psyllids, carried out on an asexual population of the holarctic species Cacopsylla myrtilli W. Wagner from northeast Finland. Preparations of mature eggs extracted from females revealed 39 univalent chromosomes in prophase and metaphase cells. Hence, female meiosis is of apomictic type and replaced by a modified mitosis. The karyotype consists of 3n = 39 (36 + XXX). Clearly, the population is triploid, the haploid number being n = 12 + X as characteristic of the genus Cacopsylla as a whole. As typical for Psylloidea, the chromosomes are holokinetic, only slightly varying in size and without any visible markers, rendering impossible the precise identification of triplets of homologous chromosomes in the triploid complement. The distribution of bisexual and parthenogenetic populations of C. myrtilli throughout the world is briefly given, and a possible origin of the triploid parthenogenetic population is discussed.