Publications by authors named "Brett J Pellock"

Manganese (Mn) and Fe indicator of reduction in soils (IRIS) devices are low-cost, convenient tools for identifying reducing conditions in soils. Because Mn is reduced at similar redox potentials as nitrate, there is considerable interest in using Mn IRIS tools for understanding microbial reduction of Mn as a surrogate for processes such as denitrification. However, the sensitivity of these devices to differences in Mn-reducing capacity has not been empirically investigated.

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The RNA chaperone Hfq fulfills important roles in small regulatory RNA (sRNA) function in many bacteria. Loss of Hfq in the dissimilatory metal reducing bacterium Shewanella oneidensis strain MR-1 results in slow exponential phase growth and a reduced terminal cell density at stationary phase. We have found that the exponential phase growth defect of the hfq mutant in LB is the result of reduced heme levels.

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The Drosophila protocadherin Fat (Ft) regulates growth, planar cell polarity (PCP) and proximodistal patterning. A key downstream component of Ft signaling is the atypical myosin Dachs (D). Multiple regions of the intracellular domain of Ft have been implicated in regulating growth and PCP but how Ft regulates D is not known.

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Background: Hfq is an RNA chaperone protein that has been broadly implicated in sRNA function in bacteria. Here we describe the construction and characterization of a null allele of the gene that encodes the RNA chaperone Hfq in Shewanella oneidensis strain MR-1, a dissimilatory metal reducing bacterium.

Results: Loss of hfq in S.

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Although essential in mammals, in flies the importance of mitochondrial outer membrane permeabilization for apoptosis remains highly controversial. Herein, we demonstrate that Drosophila Omi (dOmi), a fly homologue of the serine protease Omi/HtrA2, is a developmentally regulated mitochondrial intermembrane space protein that undergoes processive cleavage, in situ, to generate two distinct inhibitor of apoptosis (IAP) binding motifs. Depending upon the proapoptotic stimulus, mature dOmi is then differentially released into the cytosol, where it binds selectively to the baculovirus IAP repeat 2 (BIR2) domain in Drosophila IAP1 (DIAP1) and displaces the initiator caspase DRONC.

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Exposure of phosphatidylserine is a conserved feature of apoptotic cells and is thought to act as a signal for engulfment of the cell corpse. A putative receptor for phosphatidylserine (PSR) was previously identified in mammalian systems. This receptor is proposed to function in engulfment of apoptotic cells, although gene ablation of PSR has resulted in a variety of phenotypes.

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Article Synopsis
  • Mutations that disable either merlin or expanded lead to increased cell growth and division in Drosophila, indicating that both proteins play a critical role in controlling cell proliferation.
  • Mer and Ex are part of the Band 4.1 protein superfamily and seem to function together, but they also have distinct effects on cell behavior, such as how they manage the cell cycle and apoptosis during development.
  • The study highlights that while both proteins help limit tissue growth, they influence different downstream pathways, with Ex playing a unique role in regulating Wingless protein levels, unlike Mer or the Hippo pathway.
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Rhizobia are nitrogen-fixing bacteria that establish endosymbiotic associations with legumes. Nodule formation depends on various bacterial carbohydrates, including lipopolysaccharides, K-antigens, and exopolysaccharides (EPS). An acidic EPS from Rhizobium sp.

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Production of complex extracellular polysaccharides (EPSs) by the nitrogen-fixing soil bacterium Sinorhizobium meliloti is required for efficient invasion of root nodules on the host plant alfalfa. Any one of three S. meliloti polysaccharides, succinoglycan, EPS II, or K antigen, can mediate infection thread initiation and extension (root nodule invasion) on alfalfa.

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