Isolation and characterization of superdormant spores of Bacillus species.
Superdormant spores of Bacillus subtilis and Bacillus megaterium were isolated in 4 to 12% yields following germination with high nutrient levels that activated one or two germinant receptors. These superdormant spores did not germinate with the initial nutrients or those that stimulated other germinant receptors, and the superdormant spores' defect was not genetic. The superdormant spores did, however, germinate with Ca(2+)-dipicolinic acid or dodecylamine. Although these superdormant spores did not germinate with high levels of nutrients that activated one or two nutrient germinant receptors, they germinated with nutrient mixtures that activated more receptors, and using high levels of nutrient mixtures activating more germinant receptors decreased superdormant spore yields. The use of moderate nutrient levels to isolate superdormant spores increased their yields; the resultant spores germinated poorly with the initial moderate nutrient concentrations, but they germinated well with high nutrient concentrations. These findings suggest that the levels of superdormant spores in populations depend on the germination conditions used, with fewer superdormant spores isolated when better germination conditions are used. These findings further suggest that superdormant spores require an increased signal for triggering spore germination compared to most spores in populations. One factor determining whether a spore is superdormant is its level of germinant receptors, since spore populations with higher levels of germinant receptors yielded lower levels of superdormant spores. A second important factor may be heat activation of spore populations, since yields of superdormant spores from non-heat-activated spore populations were higher than those from optimally activated spores.

title: Effects of Mn levels on resistance of Bacillus megaterium spores to heat, radiation and hydrogen peroxide.
abstract: To determine the effects of Mn levels in Bacillus megaterium sporulation and spores on spore resistance.



Bacillus megaterium was sporulated with no added MnCl(2) and up to 1 mmol l(-1) MnCl(2). The resultant spores were purified and loosely bound Mn removed, and spore Mn levels were found to vary c. 100-fold. The Mn level had no effect on spore γ-radiation resistance, but B. megaterium spores with elevated Mn levels had higher resistance to UVC radiation (as did Bacillus subtilis spores), wet and dry heat and H(2)O(2). However, levels of dipicolinic acid and the DNA-protective α/β-type small, acid-soluble spore proteins were the same in spores with high and low Mn levels.



Mn levels either in sporulation or in spores are important factors in determining levels of B. megaterium spore resistance to many agents, with the exception of γ-radiation.



The Mn level in sporulation is an important factor to consider when resistance properties of B. megaterium spores are examined, and will influence the UV resistance of B. subtilis spores, some of which are used as biological dosimeters.

title: Superdormant spores of Bacillus species have elevated wet-heat resistance and temperature requirements for heat activation.
abstract: Purified superdormant spores of Bacillus cereus, B. megaterium, and B. subtilis isolated after optimal heat activation of dormant spores and subsequent germination with inosine, d-glucose, or l-valine, respectively, germinate very poorly with the original germinants used to remove dormant spores from spore populations, thus allowing isolation of the superdormant spores, and even with alternate germinants. However, these superdormant spores exhibited significant germination with the original or alternate germinants if the spores were heat activated at temperatures 8 to 15 degrees C higher than the optimal temperatures for the original dormant spores, although the levels of superdormant spore germination were not as great as those of dormant spores. Use of mixtures of original and alternate germinants lowered the heat activation temperature optima for both dormant and superdormant spores. The superdormant spores had higher wet-heat resistance and lower core water content than the original dormant spore populations, and the environment of dipicolinic acid in the core of superdormant spores as determined by Raman spectroscopy of individual spores differed from that in dormant spores. These results provide new information about the germination, heat activation optima, and wet-heat resistance of superdormant spores and the heterogeneity in these properties between individual members of dormant spore populations.

title: The preparation, germination properties and stability of superdormant spores of Bacillus cereus.
abstract: To determine yields, germination and stability of superdormant Bacillus cereus spores.



Superdormant B. cereus spores were isolated by germination with high concentrations of inosine or L-alanine in 2-5% yield and did not germinate with high concentrations of either of these germinants, but germinated like starting spores with Ca-DPA, dodecylamine, L-alanine plus inosine or concentrated complete medium. Yields of superdormant spores from germinations with low inosine concentrations were higher, and these spores germinated poorly with low inosine, but relatively normally with high inosine. Yields of superdormant spores were also higher when nonheat-activated spores were germinated. Superdormant spores stored at 4 degrees C slowly recovered some germination capacity, but recovery was slowed significantly at -20 degrees C and -80 degrees C.



Factors that influence levels of superdormant B. cereus spores and the properties of such spores are similar to those in B. megaterium and B. subtilis, suggesting there are common mechanisms involved in superdormancy of Bacillus spores.



Superdormant spores are a major concern in the food industry, because the presence of such spores precludes decontamination strategies based on triggering spore germination followed by mild killing treatments. Studies of the properties of superdormant spores may suggest ways to eliminate them.

title: Full genomic analysis of a simian SA11-like G3P[2] rotavirus strain isolated from an asymptomatic infant: identification of novel VP1, VP6 and NSP4 genotypes.
abstract: We report here the full genomic analysis of a simian SA11-like G3P[2] group A rotavirus (GAR) strain, B10, isolated from an asymptomatic infant in Kenya in 1987. By nucleotide sequence identities and phylogenetic analyses, the VP7-VP4-VP2-VP3-NSP1-NSP2-NSP3-NSP5 genes of strain B10 exhibited maximum genetic relatedness to those of the different isolates of simian strain SA11, and were assigned to the G3-P[2]-C5-M5-A5-N5-T5-H5 genotypes, respectively. On the other hand, the VP1, VP6 and NSP4 genes of strain B10 did not belong to any of the established GAR genotypes, and therefore, were assigned to new genotype numbers R8, I16 and E13, respectively, by the Rotavirus Classification Working Group. These observations suggested that strain B10 might have originated from reassortment event/s involving simian SA11-like strains and GAR strains from unknown animal host species (possibly other wild animals) preceding transmission to humans. Alternatively, considering the lack of data on simian GARs, it might be also possible that the VP1, VP6 and NSP4 genes of strain B10 are those of unknown simian strains, and that strain B10 might be a typical simian strain that was directly transmitted to humans. Therefore, either hypothesis pointed towards a rare instance of possible direct transmission of GARs from an animal host (possibly a monkey or some other wild animal) to humans. This was corroborated by the presence of different species of wild animals including non-human primates, and unhygienic conditions at the sampling site. To our knowledge, the present study is the first report on the detection of a simian SA11-like G3P[2] GAR strain in humans.

title: Removal of carbonaceous and nitrogenous pollutants from a synthetic wastewater using a membrane-coupled bioreactor
abstract: Two modified Ludzack-Ettinger (MLE)-type membrane-coupled bioreactors (MBRs) were investigated in this study for the purpose of removing both nitrogenous and carbonaceous pollutants from a synthetic wastewater. During the first MBR experiment, removal efficiencies were high (>90%) for chemical oxygen demand (COD) and ammonia, but total nitrogenous pollutant removal efficiency was poor (~25%). Bacterial community analysis of ammonia oxidizing bacteria (AOB) by a nested PCR-DGGE approach detected two Nitrosomonas-like populations and one Nitrosospira-like population. During the initial portion of the second MBR experiment, COD and ammonia removal efficiencies were similar to the first MBR experiment until the COD of the influent wastewater was increased to provide additional electron donors to support denitrification. Total nitrogen removal efficiencies eventually exceeded 90%, with a hydraulic residence time (HRT) of 24 h and a recirculation ratio of 8. When the HRT of the MBR experiment was decreased to 12 h, however, ammonia removal efficiency was adversely affected. A subsequent increase in the HRT to 18 h helped improve removal efficiencies for both ammonia (>85%) and total nitrogenous compounds (~70%). Our research demonstrates that MBRs can be effectively designed to remove both carbonaceous and nitrogenous pollutants. The ability of the microbial community to switch between anoxic (denitrifying) and oxic (nitrifying) conditions, however, represents a critical process constraint for the application of MLE-type MBR systems, such that little benefit is gained compared to conventional designs.

title: Cell density-dependent transcriptional activation of endocrine-related genes in human adipose tissue-derived stem cells.
abstract: Adipose tissue is recognized as an endocrine organ that plays an important role in human diseases such as type II diabetes and cancer. Human adipose tissue-derived stem cells (ASCs), a distinct cell population in adipose tissue, are capable of differentiating into multiple lineages including adipogenesis. When cultured in vitro under a confluent condition, ASCs reach a commitment stage for adipogenesis, which can be further induced into terminally differentiated adipocytes by a cocktail of adipogenic factors. Here we report that the confluent state of ASCs triggers transcriptional activation cascades for genes that are responsible for the endocrine function of adipose tissue. These include insulin-like growth factor 1 (IGF-1) and aromatase (Cyp19), a key enzyme in estrogen biosynthesis. Despite similar adipogenic potentials, ASCs from different individuals display huge variations in activation of these endocrine-related genes. Bioinformatics and experimental data suggest that transcription factor Foxo1 controls a large number of "early" confluency-response genes, which subsequently induce "late" response genes. Furthermore, siRNA-mediated knockdown of Foxo1 substantially compromises the ability of committed ASCs to stimulate tumor cell migration in vitro. Thus, our work suggests that cell density is an important determinant of the endocrine potential of ASCs.

title: Management of donors for heart and heart-lung transplantation.
abstract: The quality of donor organs will determine the quality of life for the recipient and the importance of optimal management of the multi-organ donor is that the organs may benefit up to five, critically ill, patients. The basic principle is to maintain sufficient preload to minimise the need for inotropic support and it is recommended that all multiple organ donors should have central venous and arterial pressure monitoring in addition to adequate venous access. The importance of the choice of fluid for volume expansion and the management of the hormonal disturbances which follow brain death are considered.

title: Mechanical phenotype is important for stromal aromatase expression
abstract: Evidence that aromatase expression in tumor-associated breast stroma is elevated, provides a rationale for use of aromatase inhibitors (AIs) in breast cancer treatment. However, regulation of local aromatase expression in cancer-free breast stroma is poorly understood. Recent clinical work indicates that stromal cells in dense breast tissue tend to express higher levels of aromatase than their counterpart from non-dense tissue. Consistent with the clinical observation, our cell culture-based study indicated that cell density, cell shape, and extracellular matrix (ECM) significantly induced stromal aromatase expression via a distinct signal transduction pathway. In addition, we identified a number of cell surface markers that are commonly associated with aromatase-expressing stromal cells. As mammographic density is one of the strongest and most prevalent risk factors for breast cancer, these findings provide a potential mechanistic link between alterations in tissue composition of dense breast tissue and increased stromal aromatase expression. Further exploration of the in vitro model system may advance understanding of an important problem in breast cancer biology.