Inhibition of methanogenesis from acetate by Cr+3 and ammonia

Summary 4000 mg/l of N–NH₄ ⁺ and 12 mg/l or Cr⁺³ caused a 50% reduction in aceticlastic methanogenic activity of an anaerobic sludge.Methanosarcina-like andMethanothrix-like cells were differently affected by the toxicants. The inhibition caused by Cr⁺³ was reverted by its removal, by addition of iron and by increasing the biomass.     

Factors controlling the metabolic response to glucose in isolated rat lung cells

Glucose decreases the oxygen utilization by isolated rat lung cells. Its effect displays saturation type kinetics with a “Ki” of 2.2. mM. The similarity of this value with the reported “Km” of 2.4 mM described for glucose uptake by these cells, suggests that both processes may be intimately related and both of them are under the control of the same rate limiting step. Several arguments point to glucose transport into these cells as the most important rate limiting step for its utilization: 1) Phloridzin prevented glucose inhibition of oxygen uptake while mannoheptulose did not; 2) The activity of hexokinase which is the least active glycolytic enzyme in these cells far exceeded the observed rates of glucose utilization and a decrease of 45 per cent in its activity in starved animals did not affect the rate of glucose uptake; 3) The “Km” of hexokinase for glucose is two orders of magnitude below the observed “Km” for glucose uptake and the “Ki” for glucose inhibition of respiration.     

Characterization of secreted proteases of Paenibacillus larvae, potential virulence factors involved in honeybee larval infection

Paenibacillus larvae is the causative agent of American Foulbrood (AFB), the most severe bacterial disease that affects honeybee larvae. AFB causes a significant decrease in the honeybee population affecting the beekeeping industry and agricultural production. After infection of larvae, P. larvae secretes proteases that could be involved in the pathogenicity. In the present article, we present the secretion of different proteases by P. larvae. Inhibition assays confirmed the presence of metalloproteases. Two different proteases patterns (PP1 and PP2) were identified in a collection of P. larvae isolates from different geographic origin. Forty nine percent of P. larvae isolates showed pattern PP1 while 51% exhibited pattern PP2. Most isolates belonging to genotype ERIC I - BOX A presented PP2, most isolates belonging to ERIC I - BOX C presented PP1 although relations were not significant. Isolates belonging to genotypes ERIC II and ERIC III presented PP2. No correlation was observed between the secreted proteases patterns and geographic distribution, since both patterns are widely distributed in Uruguay. According to exposure bioassays, isolates showing PP2 are more virulent than those showing PP1, suggesting that difference in pathogenicity could be related to the secretion of proteases.     

On the estimation of hip joint loads through musculoskeletal modeling

Biomechanics and Modeling in Mechanobiology - Noninvasive estimation of joint loads is still an open challenge in biomechanics. Although musculoskeletal modeling represents a solid resource,...     

Paleodietary analysis on the prehistoric population of El Hierro (Canary Islands)

In order to deepen our knowledge of the dietary habits of the prehispanic inhabitants of El Hierro, we have determined bone strontium (Sr), manganese (Mn), magnesium (Mg), copper (Cu), zinc (Zn), and calcium (Ca) in 52 human tibiae (23 belonging to males and 20 to females individuals) buried in a single burial cave; in 21 modern individuals who served as controls; and in 11 bones of herbivores found at archeological sites of the Canary Islands. Results suggest that females consumed a more vegetarian diet, although site-corrected Sr/Ca ratio of both males and females speaks for a mixed-diet consumption.     

Nuclear inositide signaling: An appraisal of phospholipase C β1 behavior in myelodysplastic and leukemia cells

Location impinges on function of some of the main players of nuclear inositol lipid cycle. Here we have discussed the behavior of PI-PLCβ1 in myelodysplastic and cultured leukemia cells.The presence of a cryptic deletion of PI-PLCβ1 gene in high-risk MDS patients is accompanied by altered expression of its mRNA in that the overall decrease of mRNA is characterized by a dramatic decrease of the splicing variant 1a, which is cytosolic and partially nuclear, whilst the splicing variant 1b is still highly represented. This suggests that altered expression of nuclear PI-PLCβ1 could be involved in a disregulation of the cell cycle and have also important effects on cell apoptotic pathways.Moreover, in cultured leukemia cells (Felc) it has been reported by means of a proteomic approach that the splicing factor SRp20 interacts with nuclear PI-PLCβ1 and its expression is modulated by this signaling molecule.All in all, it appears more and more evident that nuclear signaling elicited by PI-PLCβ1 is a key event in the control of cell cycle progression.