Physiological Studies of Methane- and Methanol-Oxidizing Bacteria: Immunological Comparison of a Primary Alcohol Dehydrogenase from Methylococcus capsulatus and Pseudomonas sp. M27

A primary alcohol dehydrogenase was purified from cell extracts of two apparently unrelated microorganisms, namely, Pseudomonas sp. M27 and Methylococcus capsulatus. Rabbit antiserum prepared against the purified enzyme from M. capsulatus revealed distinctive antigenic determinants by quantitative and gel precipitin reactions. Rabbit antiserum to M27 enzyme detected both distinctive and shared antigenic determinants. Certain methane- and methanol-oxidizing bacteria were grouped on the basis of serological cross-reacting enzyme specificities.     

Chronobiological aspects of the host-parasite relationships between Biomphalaria glabrata and Schistosoma mansoni: cercarial production and infectivity, and growth kinetics of the host

In the Biomphalaria glabrata-Schistosoma mansoni association, variations in cercarial production, in cercarial infectivity, and in the growth of infected snails are rhythmic. These chronobiological aspects are correlated with the dynamics of the intramolluscan larval stages of the parasite during the course of the infection. Rhythmic variations in the growth kinetics of infected snails are interpreted in terms of host-parasite metabolic exchanges.     

Analysis of mutation in human cells by using an Epstein-Barr virus shuttle system.

We developed highly sensitive shuttle vector systems for detection of mutations formed in human cells using autonomously replicating derivatives of Epstein-Barr virus (EBV). EBV vectors carrying the bacterial lacI gene as the target for mutation were established in human cells and later returned to Escherichia coli for rapid detection and analysis of lacI mutations. The majority of the clonal cell lines created by establishment of the lacI-EBV vector show spontaneous LacI- frequencies of less than 10(-5) and are suitable for studies of induced mutation. The ability to isolate clonal lines represents a major advantage of the EBV vectors over transiently replicating shuttle vectors (such as those derived from simian virus 40) for the study of mutation. The DNA sequence changes were determined for 61 lacI mutations induced by exposure of one of the cell lines to N-nitroso-N-methylurea. A total of 33 of 34 lacI nonsense mutations and 26 of 27 missense mutations involve G X C to A X T transitions. These data provide support for the mutational theory of cancer.     

In vitro antimicrobial and anticancer potential of hinokitiol against oral pathogens and oral cancer cell lines

Hinokitiol is a natural component isolated from Chamacyparis taiwanensis. It has anti-microbial activity, and has been used in oral care products. The minimal inhibitory concentration (MIC) and minimal microbicidal concentration (MMC) of hinokitiol against MRSA, Aggregatibacter actinomycetemcomitans, Streptococcus mutans, and Candida albicans were determined by the agar and broth dilution method (MIC: 40–110 μM; MMC: 50–130 μM); the paradoxical inhibition phenomenon (PIP) was observed in A. actinomycetemcomitans and S. mutans. The PIP can be described as microbial growth occurring in the presence of both high and low concentrations of a compound, between which microbial growth is inhibited. The PIP was confirmed using a kinetic microplate and inhibition zone methods. The PIP was also observed in MRSA. The low autolysin activity somehow correlated to the PIP positive. The cell diameter was increased in all the pathogens, and the transition was inhibited in C. albicans following hinokitiol treatment. Hinokitiol is also a potential anticancer drug. The 200 μM of hinokitiol has significant antimicrobial and cytotoxic activities against oral pathogens and oral squamous cell carcinoma cell lines, respectively, and lower cytotoxic effects for normal human oral keratinocytes, indicating that hinokitiol displays a high potential for safe and effective applications in oral health care.     

Glucocorticoids Distinctively Modulate the CFTR Channel with Possible Implications in Lung Development and Transition into Extrauterine Life

During fetal development, the lung is filled with fluid that is secreted by an active Cl- transport promoting lung growth. The basolateral Na⁺,K⁺,2Cl^- cotransporter (NKCC1) participates in Cl^- secretion. The apical Cl^- channels responsible for secretion are unknown but studies suggest an involvement of the cystic fibrosis transmembrane conductance regulator (CFTR). CFTR is developmentally regulated with a high expression in early fetal development and a decline in late gestation. Perinatal lung transition is triggered by hormones that stimulate alveolar Na⁺ channels resulting in fluid absorption. Little is known on how hormones affect pulmonary Cl^- channels. Since the rise of fetal cortisol levels correlates with the decrease in fetal CFTR expression, a causal relation may be assumed. The aim of this study was to analyze the influence of glucocorticoids on pulmonary Cl^- channels. Alveolar cells from fetal and adult rats, A549 cells, bronchial Calu-3 and 16HBE14o- cells, and primary rat airway cells were studied with real-time quantitative PCR and Ussing chambers. In fetal and adult alveolar cells, glucocorticoids strongly reduced Cftr expression and channel activity, which was prevented by mifepristone. In bronchial and primary airway cells CFTR mRNA expression was also reduced, whereas channel activity was increased which was prevented by LY-294002 in Calu-3 cells. Therefore, glucocorticoids strongly reduce CFTR expression while their effect on CFTR activity depends on the physiological function of the cells. Another apical Cl^- channel, anoctamin 1 showed a glucocorticoid-induced reduction of mRNA expression in alveolar cells and an increase in bronchial cells. Furthermore, voltage-gated chloride channel 5 and anoctamine 6 mRNA expression were increased in alveolar cells. NKCC1 expression was reduced by glucocorticoids in alveolar and bronchial cells alike. The results demonstrate that glucocorticoids differentially modulate pulmonary Cl^- channels and are likely causing the decline of CFTR during late gestation in preparation for perinatal lung transition.     

Developmental signals do not further accentuate nonuniform postpneumonectomy compensatory lung growth.

Mechanical forces imposed on lung tissue constitute major stimuli for normal lung development and postpneumonectomy (PNX) compensatory growth and remodeling. Superimposing developmental signals on PNX signals augments compensatory alveolar growth but exaggerates airway-parenchymal dissociation (i.e., dysanaptic lung growth); the latter tends to offset benefits derived from the former. In adult dogs after PNX, lobar expansion and growth of the remaining lobes were markedly non-uniform (Ravikumar et al. J Appl Physiol 97:1567-1574, 2004). We hypothesized that superimposing developmental and post-PNX signals further accentuates nonuniformity of lobar growth. We used high-resolution computed tomography (HRCT) to follow regional lung expansion and growth in foxhounds undergoing right PNX at 2.5 mo of age compared with litter-matched control (Sham) animals; scans were performed 4 and 10 mo following surgery, i.e., before and after somatic maturity. Air and tissue volumes were measured in each lobe; tissue volume estimated by HRCT includes air-free tissue and blood in small vessels <1 mm. Interlobar nonuniformity of tissue volume was absent at 4 mo but evident 10 mo after PNX; growth of the remaining left lower lobe gradually lagged behind other lobes. At maturity, nonuniformity of lobar growth in pneumonectomized puppies was similar to that previously reported in pneumonectomized adults. We conclude that superimposing developmental and post-PNX signals enhances some aspects of compensatory lung growth and remodeling without altering its nonuniform spatial distribution.     

Ankyrin repeat domain-encoding genes in the wPip strain of Wolbachia from the Culex pipiens group

Background  

Wolbachia are obligate endosymbiotic bacteria maternally transmitted through the egg cytoplasm that are responsible for several reproductive disorders in their insect hosts, such as cytoplasmic incompatibility (CI) in infected mosquitoes. Species in the Culex pipiens complex display an unusually high number of Wolbachia-induced crossing types, and based on present data, only the wPip strain is present.     

Cercarial shedding patterns of Schistosoma bovis and S. haematobium from single and mixed infections of Bulinus truncatus

The cercarial shedding of Schistosoma bovis and S. haematobium were studied in single and mixed infections in the snail host Bulinus truncatus. The two species displayed a distinctive diurnal cercarial emergence with an earlier shedding pattern for S. bovis than S. haematobium (the average emergence peaks were respectively at 0800 h and 1200 h). In mixed infections, each species kept its own cercarial shedding rhythm with no marked alterations. The cercarial emergence pattern is proposed as a new method to identify natural mixed infections in the snail intermediate hosts. The interactions between the two parasites are discussed.