Mineralization of phenanthrene by a Mycobacterium sp

A Mycobacterium sp., designated strain BG1, able to utilize the polycyclic aromatic hydrocarbon phenanthrene as the sole carbon and energy source was isolated from estuarine sediment following enrichment with the hydrocarbon. Unlike other phenanthrene degraders, this bacterium degraded phenanthrene via 1-hydroxy-2-naphthoic acid without accumulating this or other aromatic intermediates, as shown by high-performance liquid chromatography. Degradation proceeded via meta cleavage of protocatechuic acid. Different nonionic surfactants (Tween compounds) solubilized the phenanthrene to different degrees and enhanced phenanthrene utilization. The order of enhancement, however, did not correlate perfectly with increased solubility, suggesting physiological as well as physicochemical effects of the surfactants. Plasmids of approximately 21, 58, and 77 megadaltons were detected in cells grown with phenanthrene but not in those which, after growth on nutrient media, lost the phenanthrene-degrading phenotype. Given that plasmid-mediated degradations of aromatic hydrocarbons generally occur via meta cleavages, it is of interest that the addition of pyruvate, a product of meta cleavage, supported rapid mineralization of phenanthrene in broth culture; succinate, a product of ortho cleavage, supported growth but completely repressed the utilization of phenanthrene. The involvement of plasmids may have given rise to the unusual degradation pattern that was observed.

Two-Stage Mineralization of Phenanthrene by Estuarine Enrichment Cultures

The polycyclic aromatic hydrocarbon phenanthrene was mineralized in two stages by soil, estuarine water, and sediment microbial populations. At high concentrations, phenanthrene was degraded, with the concomitant production of biomass and accumulation of Folin-Ciocalteau-reactive aromatic intermediates. Subsequent consumption of these intermediates resulted in a secondary increase in biomass. Analysis of intermediates by high-performance liquid chromatography, thin-layer chromatography, and UV absorption spectrometry showed 1-hydroxy-2-naphthoic acid (1H2NA) to be the predominant product. A less pronounced two-stage mineralization pattern was also observed by monitoring 14 CO 2 production from low concentrations (0.5 mg liter −1 ) of radiolabeled phenanthrene. Here, mineralization of 14 C-labeled 1H2NA could explain the incremental 14 CO 2 produced during the later part of the incubations. Accumulation of 1H2NA by isolates obtained from enrichments was dependent on the initial phenanthrene concentration. The production of metabolites during polycyclic aromatic hydrocarbon biodegradation is discussed with regard to its possible adaptive significance and its methodological implications.

Chlamydia psittaci: is tonsillar tissue the portal of entry in ovine enzootic abortion?

Ewes at 70 days of gestation were exposed by various routes to a culture of Chlamydia psittaci. Chlamydial infection of fetal tissues, generally accompanied by abortion, was observed only in four of six ewes inoculated via the tonsillar crypts and in five of seven ewes injected subcutaneously; most of these also developed antibodies to C psittaci. Seroconversion after normal lambing was also observed in most ewes inoculated orally or by stomach tube, despite failure to detect chlamydia in them.

Microbiological and serological studies on caprine pneumonias in Oman

Eight of 10 typical cases of contagious caprine pleuro-pneumonia in Oman yielded strain F38-like mycoplasmas from the lungs in high titre, but no other mycoplasmas: both negative animals had been treated with tylosin shortly before death. Among 21 other lungs examined three of six cases of acute pneumonia yielded Mycoplasma ovipneumoniae; one also yielded M capricolum. M ovipneumoniae was also isolated from all eight cases of chronic pneumonia sampled from an abattoir, and from the lungs of three animals which died without overt signs of pneumonia. A single isolate of M arginini and three of unidentified mycoplasmas were also obtained from goats with and without pneumonia. Various bacterial species were isolated, none of which predominated. Antibodies to M mycoides subspecies capri (M m capri) and strain F38 were detected in sera from eight different sources. Assuming titres of 1 in 40 or more as positive in the indirect haemagglutination test used, 29 per cent of 422 serum samples had antibodies to M m capri alone, 2.6 per cent to strain F38 alone and 3.6 per cent to both organisms. These results confirm the presence of F38-like mycoplasmas in Oman, and indicate also widespread infection with M m capri. The role of the latter in caprine pneumonias in Oman requires elucidation.

Spreading behaviour of cultured fibroblasts from carriers of Duchenne muscular dystrophy

Cultured skin fibroblasts from patients with Duchenne muscular dystrophy (DMD) are more sensitive than normal cells to prolonged exposure to the ionophore monensin. In a cell spreading assay in which cells were preincubated with monensin and subsequently allowed to adhere to and spread on a glass substratum in serum-free medium for 100 min, the mean transformed cell area of normal and DMD cells was 5.97 +/− 0.11 and 5.29 +/− 0.03, respectively. Cultured fibroblasts from carriers of DMD yielded a value of 5.59 +/− 0.03, which is intermediate between, and significantly different from, the values for both normal and DMD cultures. This result would be predicted on the basis of random X-chromosome inactivation in female carriers of this disorder. However, comparison of DMD carrier cell spreading data with data obtained from pooled and summated measurements taken from separate experiments using either normal or DMD fibroblasts suggest a more complex situation. Examination of the variance of the means of cell area for the true carrier population and the summated normal and DMD population provides evidence suggesting that some form of cellular interaction may occur between the two cell genotypes in culture.

Fibronectin glycosylation modulates fibroblast adhesion and spreading

The role of the carbohydrate residues of fibronectin concerning the specificities of that glycoprotein to interact with fibroblastic cell surfaces, gelatin, and heparin was examined. Tunicamycin was used to produce carbohydrate-depleted fibronectin; it was synthesized by cultured fibroblasts. Unglycosylated and glycosylated fibronectins were analyzed for their ability to bind gelatin and heparin, using affinity columns. Fibronectin-coated surfaces were used to quantitatively measure cell adhesion and spreading. The results showed that the lack of carbohydrates significantly increased the interaction of the protein with gelatin and markedly enhanced its ability to promote adhesion and spreading of fibroblasts. In contrast, the binding of fibronectin to heparin was not influenced by glycosylation. The composite data indicate that the Asn-linked oligosaccharides of fibronectin act as modulators of biological functions of the glycoprotein.

Behaviour of Duchenne dystrophy fibroblasts in collagen gels

In order to clarify the possible involvement of the cell surface in the pathogenesis of Duchenne muscular dystrophy, we have examined the behaviour of fibroblasts cultured from Duchenne patients in hydrated collagen lattices. No differences could be found between Duchenne and normal skin fibroblasts, either after initial seeding or following prolonged culture within the collagen gel.

Microbial flora of the eyes of cattle

The bacteria and mycoplasma occurring in the eyes of normal healthy calves were monitored in three groups of animals from purchase at about one week old to slaughter at about 15 months old. Non-haemolytic Moraxella bovis, Branhamella catarrhalis and Mycoplasma bovoculi were all isolated regularly, though their seasonal occurrence varied. The significance of these findings with respect to infectious bovine keratoconjunctivitis is discussed.

Comparison of single strains of four serotypes of Pasteurella haemolytica biotype A in experimental pneumonia of sheep

Single strains of serotypes A1, A2, A7 and A9 of Pasteurella haemolytica were separately used in combination with Mycoplasma ovipneumoniae to reproduce pneumonia. Macroscopically and microscopically the pneumonias associated with individual serotypes were similar and it is concluded that serotypes of P haemolytica isolated with low frequency in field disease may be equally virulent to common serotypes.

The relationship between endothelial dysfunction and collagen accumulation in irradiated rat lung

Male rats were killed 2 months (early fibrosis) or 6 months (peak fibrosis) after a range of single doses of 60Co gamma rays to the right hemithorax. Pulmonary arterial perfusion scans were performed at 2 months on animals scheduled for autopsy at 6 months. Lung angiotensin converting enzyme (ACE) activity was used to monitor endothelial function, and hydroxyproline (HP) concentration served as an index of interstitial collagen accumulation (fibrosis). ACE activity also was measured in right lung bronchoalveolar lavage (BAL) fluid and blood serum, to determine whether information obtained from a minimally invasive procedure might serve as an index or predictor of the severity of lung damage. Linear dose-response curves (r = 0.92-0.99) were obtained for right lung arterial perfusion, ACE activity and HP concentration. At 2 months, perfusion decreased 2.7% per Gy, ACE activity (per lung, per mg wet weight, or per mg protein) decreased 3.0-4.2% per Gy, and HP concentration (per g dry weight) increased 1.7% per Gy. At 6 months, the slopes of the response curves were virtually identical to those at 2 months; the Y intercept of the response curve for ACE activity was unchanged, whereas that for HP concentration was 50% higher at 6 than at 2 months. ACE activity and protein concentration in the BAL increased with increasing dose, but the variation within groups was too large, and the sensitivity was too low to serve as a reliable index of lung status. Serum ACE activity was independent of radiation dose at both autopsy times. Thus in rat lung, arterial perfusion, endothelial dysfunction and interstitial fibrosis exhibit similar but not identical radiosensitivities. The dose-effect curves for these three responses of the lung in situ change less than 5% per Gy over the dose range of 10-30 Gy, a smaller variation than would be predicted from endothelial cell survival data based on clonogenic assays in vitro or in vivo.

The pathogenicity of Mycoplasma ovipneumoniae and Mycoplasma arginini in ovine and caprine tracheal organ cultures

The effects of M. ovipneumoniae and M. arginini on tracheal organ cultures prepared from a neonatal kid and a foetal lamb were studied. Both organisms were isolated from the cultures throughout the 14 days of observation. M. ovipneumoniae produced ciliostasis and loss of cilia, confirmed by scanning electron microscope (SEM), after 4 days. These effects were sudden and profound in lamb explants, and gradual and less pronounced in kid explants. Clusters of organisms attached to epithelial surfaces and in association with cilia were visible by SEM. M. arginini also induced ciliostasis and cilia loss in both kid and lamb explants, but onset was more rapid, at 2 days, and there was evident recovery after day 6, with apparent regeneration of cilia. No clearly recognizable mycoplasmas were observed by SEM in M. arginini-infected explants.

The effect of monensin on cell aggregation of normal and dystrophic human skin fibroblasts

Measurements of aggregation kinetics using couette viscometry show that freshly trypsinized skin fibroblasts from patients with Duchenne muscular dystrophy have values of intercellular adhesiveness approx. 40% those of normal cells. If cells are allowed to recover from the effects of trypsinization (by incubation for 2 h at 37 degrees C in serum-containing medium) the intercellular adhesiveness of both cell types increases, and normal and Duchenne cells aggregate to the same extent. Exposure to the ionophore monensin during the recovery phase leads to suppression of recovery in both cell types, and this effect of the drug is greater in Duchenne fibroblasts. These results are discussed in relation to other data on the reported differential effects of trypsin and monensin on normal and Duchenne fibroblasts.

Biofeedback and gifted children: an initial investigation

37 intellectually gifted students were given a 15-min. training session in EMG frontalis biofeedback to determine its effectiveness for reduction of stress. While differences across sex in biofeedback training were not found, these highly able students significantly reduced their levels of tension.

The pathogenicity of some ovine or caprine mycoplasmas in the lactating mammary gland of sheep and goats

Mycoplasma ovipneumoniae, M. arginini and M. conjunctivae were each inoculated into the lactating mammary gland of goats and sheep. M. ovipneumoniae was mastitogenic in both species, causing persistent colonization, raised lacteal cell numbers, decreased milk output and separation of milk into 3 layers throughout the periods of observation in virtually all animals. Its effects in sheep were variable, however, and appeared to depend less on the strain and titre of inoculum than on individual variation in response. M. arginini and M. conjunctivae were not mastitogenic for goats, but one of each pair of sheep injected with these agents showed organism persistence at high titres and lacteal neutrophilia over 9 days of observation. Effects on milk production were obscured by the apparent poor ability of the ovine udder to regain previous yield after a fall in output, but milk consistency and appearance were only temporarily or mildly affected in these animals. A. laidlawii, injected into sheep only, produced transient effects but with poor recovery of milk production after elimination of the organism. Goats were superior to sheep in consistency of reaction and milk output, and equally if not more susceptible to intra-mammary challenge with M. ovipneumoniae. The goat was therefore concluded to be the better experimental animal in a potentially useful method for screening strains of M. ovipneumoniae for virulence.