Chlamydia-related bacteria in respiratory samples in Finland

Chlamydia-related bacteria, new members of the order Chlamydiales, are suggested to be associated with respiratory disease. We used real-time PCR to investigate the prevalence of Parachlamydia acanthamoebae, Protochlamydia spp., Rhabdochlamydia spp., Simkania negevensis and Waddlia chondrophila in samples taken from patients with suspected respiratory tract infections. Of the 531 samples analyzed, the subset of 136 samples contained 16 (11.8%) samples positive for Rhabdochlamydia spp. DNA. P. acanthamoebae, Protochlamydia spp., S. negevensis and W. chondrophila DNA were not detected among the respiratory samples investigated. These results suggest an association of Rhabdochlamydia spp. with respiratory disease.     

Bi- and trivalent glycopeptide mannopyranosides as inhibitors of type 1 fimbriae-mediated bacterial adhesion: variation of valency, aglycon and scaffolding

In order to test relevant structural parameters for effective inhibition of mannose-specific bacterial adhesion, bi- and trivalent glycopeptide α-d-mannopyranosides were synthesized that differ in their conformational properties as well as in the spatial arrangement of attached mannosyl residues. They were tested in an inhibition adhesion assay with fluorescent Escherichia coli bacteria and testing results were referenced to the inhibitory potency of methyl α-d-mannopyranoside. It was shown, that besides the nature of the mannoside aglycon moiety, scaffolding of α-d-mannopyranosides on a peptide backbone was important for the performance of the synthesized glycopeptides as inhibitors of bacterial adhesion.     

Glucose-limited high cell density cultivations from small to pilot plant scale using an enzyme-controlled glucose delivery system

The enzyme controlled substrate delivery cultivation technology EnBase(?) Flo allows a fed-batch-like growth in batch cultures. It has been previously shown that this technology can be applied in small cultivation vessels such as micro- and deep well plates and also shake flasks. In these scales high cell densities and improved protein production for Escherichia coli cultures were demonstrated. This current study aims to evaluate the scalability of the controlled glucose release technique to pilot scale bioreactors. Throughout all scales, that is, deep well plates, 3 L bioreactor and 150 L bioreactor cultivations, the growth was very similar and the model protein, a recombinant alcohol dehydrogenase (ADH) was produced with a high yield in soluble form. Moreover, EnBase Flo also was successfully used as a controlled starter culture in high cell density fed-batch cultivations with external glucose feeding. Here the external feeding pump was started after overnight cultivation with EnBase Flo. Final optical densities in these cultivations reached 120 (corresponding to about 40 g L(-1) dry cell weight) and a high expression level of ADH was obtained. The EnBase cultivation technology ensures a controlled initial cultivation under fed-batch mode without the need for a feeding pump. Because of the linear cell growth under glucose limitation it provides optimal and robust starting conditions for traditional external feed-based processes.     

Physiology of resistant Deinococcus geothermalis bacterium aerobically cultivated in low-manganese medium

This dynamic proteome study describes the physiology of growth and survival of Deinococcus geothermalis, in conditions simulating paper machine waters being aerobic, warm, and low in carbon and manganese. The industrial environment of this species differs from its natural habitats, geothermal springs and deep ocean subsurfaces, by being highly exposed to oxygen. Quantitative proteome analysis using two-dimensional gel electrophoresis and bioinformatic tools showed expression change for 165 proteins, from which 47 were assigned to a function. We propose that D. geothermalis grew and survived in aerobic conditions by channeling central carbon metabolism to pathways where mainly NADPH rather than NADH was retrieved from the carbon source. A major part of the carbon substrate was converted into succinate, which was not a fermentation product but likely served combating reactive oxygen species (ROS). Transition from growth to nongrowth resulted in downregulation of the oxidative phosphorylation observed as reduced expression of V-type ATPase responsible for ATP synthesis in D. geothermalis. The battle against oxidative stress was seen as upregulation of superoxide dismutase (Mn dependent) and catalase, as well as several protein repair enzymes, including FeS cluster assembly proteins of the iron-sulfur cluster assembly protein system, peptidylprolyl isomerase, and chaperones. Addition of soluble Mn reinitiated respiration and proliferation with concomitant acidification, indicating that aerobic metabolism was restricted by access to manganese. We conclude that D. geothermalis prefers to combat ROS using manganese-dependent enzymes, but when manganese is not available central carbon metabolism is used to produce ROS neutralizing metabolites at the expense of high utilization of carbon substrate.     

The successful double cryopreservation of rabbit (Oryctolagus cuniculus) semen in large volume using the directional freezing technique with reduced concentration of cryoprotectant

Using directional freezing, our objective was to cryopreserve rabbit semen and achieve fertility that was equal or higher than that achieved with conventional freezing. The working hypothesis was that controlling the ice-front propagation would allow reduction of DMSO concentration to <1M, in addition to the capability to freeze large volumes (2-10 mL). Moreover, single and double freezing of semen were used to demonstrate the abbreviated mechanical stress imparted by directional freezing. Single-cryopreserved semen from 15 males extended with 0% egg yolk/1.75 M DMSO, 15.3% egg yolk/0.88 M DMSO and 20% egg yolk/0M DMSO resulted in lower (P<0.05) mean+/-S.E.M. post-thaw motility (3.6+/-1.1, 28.5+/-2.8 and 36.3+/-1.8%, respectively) compared to fresh semen (73.3+/-1.2%). Semen from seven of these males, subject to double freezing using only egg yolk based extenders, resulted in post-thaw motilities of 18.1+/-2.2 and 16.4+/-3.3%. Despite the reduced functional parameters of cryopreserved semen, fertility and kindling rates of 73.9 and 56.5% for single frozen-thawed, and 28.6 and 35.7% for double frozen-thawed semen were achieved (with insemination of 98 females). There was no significant difference in fertility rate between fresh semen (87.5%) and semen that was single frozen-thawed with the 15.3% egg yolk/0.88 M DMSO extender (73.9%). In conclusion, cryopreservation of rabbit semen in large volumes using directional freezing achieved fertility rates similar to those achieved with fresh semen. Furthermore, acceptable fertility rates with double frozen-thawed semen could facilitate the future use of sex-sorted semen in rabbits.     

Absorption of pentachlorophenol (PCP) by bark chips and its role in microbial PCP degradation

A pentachlorophenol (PCP)-degrading mixed bacterial population was enriched in a biofilter filled with soft wood bark chips. We found that bark chips were essential for the degradation to proceed at PCP concentrations higher than 10M. PCP-degrading bacteria were found to be extremely sensitive to PCP. Bark chips absorbed PCP reversibly, thus detoxifying the medium and allowing degradation to proceed at higher concentrations of PCP (beyond 200M).     

Anti-oxidant supplementation decreases TBA reactants in serum of elderly

An “anti-oxidant cocktail” consisting of betacarotene, vitamins B₆, C, E, zinc, and selenium or corresponding placebos were given for one y as daily dietary supplements to 45 elderly residents of a nursing home. Initially, the serum TBA reactant levels were higher (2.7±0.7 μmol/L) than those of an ad hoc control group of healthy younger adults (2.3±0.6 μmol/L),p<0.01. After three mo supplementation, the levels among the verum elderly had decreased to 2.2±0.6 μmol/L, and they remained at this lower level until the end of the study period, whereas the placebo group showed no change. A significant inverse correlation (r=−0.428,p<0.01) existed between the concentrations of serum TBA reactants and whole blood selenium (B-Se), but only B-Se levels above 200 μg/L were associated with a decrease in serum lipid peroxides. Serum alpha-tocopherol concentration also correlated inversely with serum TBA reactants but this correlation (r=−0.273,p<0.76) was not as strong as that of B-Se. Deficient vitamin B₆ status, in biochemical terms, was observed in 25% of the elderly; a daily supplement of 2 mg B₆ fully cured all cases of deficiency. The verum group improved slightly in several psychological tests, whereas subjects on placebo remained unchanged or deteriorated during the follow-up period. Clinical amelioration among the verum subjects was reported by the nurses; no toxic side effects were reported. In conclusion, the elderly benefited biochemically and clinically of dietary antioxidant supplements.     

Hydroxylation and Dechlorination of Tetrachlorohydroquinone by Rhodococcus sp. Strain CP-2 Cell Extracts

A cell extract of a polychlorophenol-degrading bacterium, Rhodococcus sp. strain CP-2, isolated from chlorophenol-contaminated soil, was shown to dechlorinate tetrachlorohydroquinone, the first intermediate in pentachlorophenol and 2,3,5,6-tetrachlorophenol degradation. Degradation of tetrachlorohydroquinone was catalyzed by a soluble enzyme(s). The reaction sequence for complete dechlorination involved hydroxylation and three reductive dechlorinations, producing 1,2,4-trihydroxybenzene. All chlorines were thus removed from the polychlorinated compound before ring cleavage.