Bone marrow neutrophil aging in sickle cell disease mice is associated with impaired osteoblast functions

Bone loss is a common complication in individuals with sickle cell disease (SCD). The mechanism(s) of bone loss in SCD subjects has not been fully investigated, and there are no targeted therapies to prevent or treat compromised bone health in this population. Recent studies showed that depletion of gut microbiota with antibiotics significantly reduced the number of aged neutrophils, thereby dramatically improved the inflammation-related organ damages in SCD mice. Since neutrophils, abundantly present in bone marrow (BM), regulate bone cells, and BM neutrophils, induced by inflammatory cytokines, are associated with a low number of osteoblasts (OBs), we hypothesize that neutrophil aging in the BM of SCD mice impairs OB function. Flow cytometry analysis showed BM neutrophil aging was significantly increased in SCD mice that was reduced with antibiotic treatment. In vitro co-culture of calvarial OBs from control (Ctrl) mice with BM neutrophils from Ctrl or SCD mice showed that BM neutrophils from SCD mice inhibit OB function but was rescued when neutrophils were from antibiotic-treated SCD mice. In summary, there is an accumulation of aged neutrophils in BM from SCD mice that may contribute to impaired OB function, and antibiotic treatment is able to partially rescue impaired OB function by decreasing neutrophil aging in the BM of SCD mice.     

Acquisition of Salmonella flora by turtle hatchlings on commercial turtle farms

A commercial turtle pond in South Louisiana was studied to identify the mechanism by which turtle hatchlings acquire Salmonella flora. The visceral organs and mature eggs removed from 31 adult gravid female turtles over the course of two egg-laying seasons and from 37 adult females during one winter dormant period were examined bacteriologically for Salmonella. Pond water, egg nest soil, and hatchlings produced by eggs removed from the oviducts and nest soil were also tested. Eighty-eight turtles hatched from eggs removed from the oviducts of 15 turtles at necropsy did not excrete or harbor systemically Salmonella, nor were these pathogens isolated from ovarian tissue or immature eggs. The findings suggest transovarian transmission of these pathogens does not occur frequently. Turtles hatched from eggs retrieved from soil nests 1 to 2 h after deposition harbor and excrete these organisms. This result coupled with the isolation of these pathogens from the cloaca, colon contents, and bursal fluid from 18 females captured in the act of egg laying supports the cloaca to egg and nest soil to egg mode for salmonellae infection in the resultant hatchling. Salmonella arizonae and Salmonella serogroups B, C2, and E1 were isolated from the cloaca, colon contents, pond water, and nest soil, and were excreted by hatchlings produced from eggs removed from the soil nests. These same serogroups were isolated from the colon contents of 19 of 37 females tested during the dormant period, suggesting the salmonellae persist in the pond environment in the adult throughout the year.     

Correction to: From degrader to producer: reversing the gallic acid metabolism of Pseudomonas putida KT2440

International Microbiology - Gallic acid is a powerful antioxidant with multiple therapeutic applications, usually obtained from the acidic hydrolysis of tannins produced by many plants. As this...     

Cytoplasmic chloride regulates cation channels in the vacuolar membrane of plant cells

Summary This study is concerned with the characterization of the ionic currents in the vacuolar membrane (tonoplast) of plant cells. Voltage patch-clamp experiments at the whole vacuole and single channel levels were employed to study the effects of cytoplasmic chloride on the tonoplast inward rectifying currents of sugar beet cultured cells. Whole vacuole experiments showed that removal of cytoplasmic chloride induced a decrease in the level of the inward currents, an effect that was reversed upon returning to control levels of cytoplasmic chloride. Substitution of cytoplasmic chloride by any other anion (organic or inorganic) resulted in a reduction in the level of the inward currents. At a given negative tonoplast potential, the inward currents showed a linear relationship with the concentration of cytoplasmic chloride between 10 and 100 mM, with the slope of these relationships increasing as the potential was made more negative. Single channel experiments showed that reduction of cytoplasmic chloride changed the gating mechanism of the channels without affecting the single channel conductance. Reduction of cytoplasmic chloride caused a decrease in the open probability of the tonoplast cation channels by reducing their mean open time and by inducing the appearance of an additional closed state.This work was supported by the National Science and Engineering Research Council of Canada.