MYC Promotes Bone Marrow Stem Cell Dysfunction in Fanconi Anemia

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New Composite Biocarriers Engineered To Contain Adsorptive and Ion-Exchange Properties Improve Immobilized-Cell Bioreactor Process Dependability

Novel biocarriers that combine the adsorptive properties of activated carbon with the ion-exchange properties of zeolite-based type Z inorganic oxide biocarriers (D. R. Durham, L. C. Marshall, J. G. Miller, and A. B. Chmurny, Appl. Environ, Microbiol. 60:3329-3335, 1994.) were developed. These biocarriers, designated Type CZ, possess fundamental properties that heretofore have not been described for available microbial immobilization matrices. Type CZ biocarriers provide an environment that promotes dense microbial colonization and maintains bioreactor productivity by buffering immobilized microorganisms from unfavorable operating conditions. Data demonstrating protection of immobilized bacteria from organic shock loads and extended pH shocks are presented. In addition, bioreactors containing the composite Type CZ biocarriers continue to remove waste stream contaminants during periods of oxygen deprivation and nutrient limitation.     

Particle image velocimetry (PIV) study of rotating cylindrical filters for animal cell perfusion processes

In the present work, the main fluid flow features inside a rotating cylindrical filtration (RCF) system used as external cell retention device for animal cell perfusion processes were investigated using particle image velocimetry (PIV). The motivation behind this work was to provide experimental fluid dynamic data for such turbulent flow using a high‐permeability filter, given the lack of information about this system in the literature. The results shown herein gave evidence that, at the boundary between the filter mesh and the fluid, a slip velocity condition in the tangential direction does exist, which had not been reported in the literature so far. In the RCF system tested, this accounted for a fluid velocity 10% lower than that of the filter tip, which could be important for the cake formation kinetics during filtration. Evidence confirming the existence of Taylor vortices under conditions of turbulent flow and high permeability, typical of animal cell perfusion RCF systems, was obtained. Second‐order turbulence statistics were successfully calculated. The radial behavior of the second‐order turbulent moments revealed that turbulence in this system is highly anisotropic, which is relevant for performing numerical simulations of this system. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2012     

The importance of mesofauna and decomposition environment on leaf decomposition in three forests in southeastern Brazil

We examined the effects of soil mesofauna and the litter decomposition environment (above and belowground) on leaf decomposition rates in three forest types in southeastern Brazil. To estimate decomposition experimentally, we used litterbags with a standard substrate in a full-factorial experimental design. We used model selection to compare three decomposition models and also to infer the importance of forest type, decomposition environment, mesofauna, and their interactions on the decomposition process. Rather than the frequently used simple and double-exponential models, the best model to describe our dataset was the exponential deceleration model, which assumed a single organic compartment with an exponential decrease of the decomposition rate. Decomposition was higher in the wet than in the seasonal forest, and the differences between forest types were stronger aboveground. Regarding litter decomposition environment, decomposition was predominantly higher below than aboveground, but the magnitude of this effect was higher in the seasonal than in wet forests. Mesofauna exclusion treatments had slower decomposition, except aboveground into the Semi-deciduous Forest, where the mesofauna presence did not affect decomposition. Furthermore, the effect of mesofauna was stronger in the wet forests and belowground. Overall, our results suggest that, in a regional scale, both decomposers activity and the positive effect of soil mesofauna in decomposition are constrained by abiotic factors, such as moisture conditions.     

Effect of somatostatin on bile-induced acute hemorrhagic pancreatitis in the dog.

In 21 female Beagle dogs an experimental pancreatitis was induced by injection of bile into the pancreatic duct system. Beside controls, dogs received 62.5 micrograms/h cyclic somatostatin (SRIF) a continuous i.v. infusion starting with a bolus of 250 micrograms 15 minutes before or 2 hours after bile injection. Following blood parameters were determined: lipase, amylase, blood count, minerals, glucose, insulin, gastrin, secretin and CCK. Two controls died within 24 hours, the others were sacrificed after 48 hours. All pancreata were examined morephologically. The controls developed all clinical signs of acute hemorrhagic pancreatitis, whereas all SRIF-treated dogs were in much better general condition. Lipase and amylase increased in all groups. In the controls insulin, gastrin and secretin remained unchanged and CCK rose slightly. SRIF-treatment diminished insulin, CCK and the test meal-induced increase of secretin. At autopsy the pancreata of the controls were nearly entirely apoplectic. The SRIF-treated dogs showed less damage of the pancreas and no severe hemorrhagic necrosis was noted. The beneficial effect of SRIF cannot only be due to an interaction with intestinal hormones. An additional direct protective effect on the exocrine parenchyma is proposed to exist.     

Effect of abnormal atmospheric pressure conditions upon mouse liver delta-aminolevulinic acid synthetase activity

Liver delta-aminolevulinic acid synthetase activity was measured in mice living under abnormal atmospheric pressure conditions for 15 h. In the group living under low atmospheric pressure (51 kPa) the enzymic activity, either basal or induced by starvation and/or allylisopropylacetamide, was significantly (p less than 0.001) lower than that of the control group. In the group living under high atmospheric pressure (153 kPa) the enzymic activity was significantly (p less than 0.001) higher than the one of the controls. Our results might possibly be explained by changes in the cellular redox state, the heme oxygenase activity or the serum erythropoietin levels.     

Role of the JP45-Calsequestrin Complex on Calcium Entry in Slow Twitch Skeletal Muscles

We exploited a variety of mouse models to assess the roles of JP45-CASQ1 (CASQ, calsequestrin) and JP45-CASQ2 on calcium entry in slow twitch muscles. In flexor digitorum brevis (FDB) fibers isolated from JP45-CASQ1-CASQ2 triple KO mice, calcium transients induced by tetanic stimulation rely on calcium entry via La³⁺- and nifedipine-sensitive calcium channels. The comparison of excitation-coupled calcium entry (ECCE) between FDB fibers from WT, JP45KO, CASQ1KO, CASQ2KO, JP45-CASQ1 double KO, JP45-CASQ2 double KO, and JP45-CASQ1-CASQ2 triple KO shows that ECCE enhancement requires ablation of both CASQs and JP45. Calcium entry activated by ablation of both JP45-CASQ1 and JP45-CASQ2 complexes supports tetanic force development in slow twitch soleus muscles. In addition, we show that CASQs interact with JP45 at Ca²⁺ concentrations similar to those present in the lumen of the sarcoplasmic reticulum at rest, whereas Ca²⁺ concentrations similar to those present in the SR lumen after depolarization-induced calcium release cause the dissociation of JP45 from CASQs. Our results show that the complex JP45-CASQs is a negative regulator of ECCE and that tetanic force development in slow twitch muscles is supported by the dynamic interaction between JP45 and CASQs.     

Wildland fire as an atmospheric source of viable microbial aerosols and biological ice nucleating particles

The environmental sources of microbial aerosols and processes by which they are emitted into the atmosphere are not well characterized. In this study we analyzed microbial cells and biological ice nucleating particles (INPs) in smoke emitted from eight prescribed wildland fires in North Florida. When compared to air sampled prior to ignition, samples of the air–smoke mixtures contained fivefold higher concentrations of microbial cells (6.7 ± 1.3 × 10⁴ cells m⁻³) and biological INPs (2.4 ± 0.91 × 10³ INPs m⁻³ active at temperatures ≥ −15 °C), and these data significantly positively correlated with PM₁₀. Various bacteria could be cultured from the smoke samples, and the nearest neighbors of many of the isolates are plant epi- and endophytes, suggesting vegetation was a source. Controlled laboratory combustion experiments indicated that smoke emitted from dead vegetation contained significantly higher numbers of cells, INPs, and culturable bacteria relative to the green shrubs tested. Microbial viability of smoke aerosols based on formazan production and epifluorescent microscopy revealed no significant difference in the viable fraction (~80%) when compared to samples of ambient air. From these data, we estimate each fire aerosolized an average of 7 ± 4 × 10⁹ cells and 2 ± 1 × 10⁸ biological INPs per m² burned and conclude that emissions from wildland fire are sources of viable microbial aerosols to the atmosphere.Subject terms: Air microbiology, Microbial ecology, Microbial ecology, Forest ecology