Animal cell cytokinesis results from patterned activation of the small GTPase Rho, which directs assembly of actomyosin in the equatorial cortex. Cytokinesis is restricted to a portion of the cell ...cycle following anaphase onset in which the cortex is responsive to signals from the spindle. We show that shortly after anaphase onset oocytes and embryonic cells of frogs and echinoderms exhibit cortical waves of Rho activity and F-actin polymerization. The waves are modulated by cyclin-dependent kinase 1 (Cdk1) activity and require the Rho GEF (guanine nucleotide exchange factor), Ect2. Surprisingly, during wave propagation, although Rho activity elicits F-actin assembly, F-actin subsequently inactivates Rho. Experimental and modelling results show that waves represent excitable dynamics of a reaction-diffusion system with Rho as the activator and F-actin the inhibitor. We propose that cortical excitability explains fundamental features of cytokinesis including its cell cycle regulation.
Cell healing: Calcium, repair and regeneration Moe, Alison M.; Golding, Adriana E.; Bement, William M.
Seminars in cell & developmental biology,
September 2015, 2015-Sep, 2015-09-00, 20150901, Letnik:
45
Journal Article
Recenzirano
Odprti dostop
Cell repair is attracting increasing attention due to its conservation, its importance to health, and its utility as a model for cell signaling and cell polarization. However, some of the most ...fundamental questions concerning cell repair have yet to be answered. Here we consider three such questions: (1) How are wound holes stopped? (2) How is cell regeneration achieved after wounding? (3) How is calcium inrush linked to wound stoppage and cell regeneration?
Technological pedagogical content knowledge (TPACK) defines the knowledge domains required for successful technology integration. Context is identified as an important component of TPACK. The aim of ...this systematic literature review was to examine context levels and the application of TPACK in the area of English language teaching and learning. The empirical studies reviewed were published between 2009 and 2019. Initial database searches yielded 365 results from which 24 articles were included in the final content analysis. Analysis of the included studies revealed that classroom factors at the micro contextual level were addressed more frequently than those at the meso and macro contextual levels, which were frequently not taken into consideration in the definition and explanation of TPACK. The majority of studies used qualitative methods for data collection which were also commonly determined through self-reporting. When self-reporting is used, TPACK is exclusively viewed as knowledge that teachers possess regardless of their context. The data indicate that teacher's contextual factors such as dispositions are not always included in the operationalization of TPACK. Teachers' contextual factors highlight their perspectives and belief systems. A critical perspective of teacher's TPACK knowledge development across contexts and the roles teachers are assigned in the classroom are vital to understanding the paradigm shifts that inform teachers' practices and training.
Two novel Gram-stain-negative bacterial strains, Azo-3
and Azo-2, were isolated from a toluene-producing enrichment culture that originated from contaminated groundwater at a site in southeast ...Louisiana (USA). Cells are non-spore forming straight to curved rods with single polar flagella. Strains Azo-3
and Azo-2 are oxidase-positive, catalase-negative, use nitrate and nitrite as electron acceptors, and are able to fix nitrogen. Poly-β-hydroxybutyrate storage granules are produced. Dominant fatty acids when grown in R2A medium at 37 °C are C
, summed feature 3 (C
ω7
and/or C
iso 2OH), C
cyclo and C
ω7
. 16S rRNA gene sequence based phylogenetic analysis indicated that the strains cluster within the family
, class
, most closely related to but distinct from type strains of the species
(96.94% similarity) and
(95.10% similarity). Complete genome sequences determined for strains Azo-3
and Azo-2 revealed DNA G+C content of 62.70 mol%. Genome-wide comparisons based on average nucleotide identity by orthology and estimated DNA-DNA hybridization values combined with phenotypic and chemotaxonomic traits and phylogenetic analysis indicate that strains Azo-3
and Azo-2 represent a novel species within the genus
for which the name
sp. nov. is proposed. The type strain of
is Azo-3
(=NRRL B-65590
=DSM 112046
).
Global health researchers often discount mutual learning and benefit to address shared health challenges across high and low- and middle-income settings. Drawing from a 30-year partnership called ...AMPATH that started between Indiana University in the US and Moi University in Kenya, we describe an innovative approach and program for mutual learning and benefit coined 'reciprocal innovation.' Reciprocal innovation harnesses a bidirectional, co-constituted, and iterative exchange of ideas, resources, and innovations to address shared health challenges across diverse global settings. The success of AMPATH in Kenya, particularly in HIV/AIDS and community health, resulted in several innovations being 'brought back' to the US. To promote the bidirectional flow of learning and innovations, the Indiana CTSI reciprocal innovation program hosts annual meetings of multinational researchers and practitioners to identify shared health challenges, supports pilot grants for projects with reciprocal exchange and benefit, and produces educational and training materials for investigators. The transformative power of global health to address systemic health inequities embraces equitable and reciprocal partnerships with mutual benefit across countries and communities of academics, practitioners, and policymakers. Leveraging a long-standing partnership, the Indiana CTSI has built a reciprocal innovation program with promise to redefine global health for shared wellbeing at a global scale.
Two recently reported bacterial strains that are able to reductively dehalogenate polychlorinated aliphatic alkanes, including 1,2,3-trichloropropane, 1,2-dichloropropane, 1,1,2,2-tetrachloroethane, ...1,1,2-trichloroethane and 1,2-dichloroethane, were further characterized to clarify their taxonomic position. The two strains, designated BL-DC-8 and BL-DC-9(T), were mesophilic, non-spore-forming, non-motile, Gram-negative staining and strictly anaerobic. Cells were irregular cocci, 0.3-0.6 mum in diameter. The two strains were resistant to ampicillin and vancomycin. Hydrogen was utilized as an electron donor. The genomic DNA G+C content of strains BL-DC-8 and BL-DC-9(T) was 54.0 and 53.8 mol%, respectively. The major cellular fatty acids were C(18 : 1)omega9c, C(16 : 1)omega9c, C(16 : 0) and C(14 : 0). Phylogenetic analyses based on 16S rRNA gene sequences indicated that the strains cluster within the phylum Chloroflexi, but are related only distantly to all recognized taxa in the phylum. Morphological, physiological and chemotaxonomic traits as well as phylogenetic analysis support the conclusion that these two strains represent a novel species of a new genus in the phylum Chloroflexi, for which the name Dehalogenimonas lykanthroporepellens gen. nov., sp. nov. is proposed. The type strain of Dehalogenimonas lykanthroporepellens is BL-DC-9(T) (=ATCC BAA-1523(T) =JCM 15061(T)).
A strictly anaerobic, Gram-stain-negative, non-spore-forming bacterium designated NSZ-14T, isolated from contaminated groundwater in Louisiana (USA), was characterized using a polyphasic approach. ...Strain NSZ-14T reductively dehalogenated a variety of polychlorinated aliphatic alkanes, producing ethene from 1,2-dichloroethane, propene from 1,2-dichloropropane, a mixture of cis- and trans-1,2-dichloroethene from 1,1,2,2-tetrachloroethane, vinyl chloride from 1,1,2-trichloroethane and allyl chloride (3-chloro-1-propene) from 1,2,3-trichloropropane. Formate or hydrogen could both serve as electron donors. Dechlorination occurred between pH 5.5 and 7.5 and over a temperature range of 20-37 °C. Major cellular fatty acids included C18 : 1ω9c, C14 : 0 and C16 : 0. 16S rRNA gene sequence-based phylogenetic analysis indicated that the strain clusters within the class Dehalococcoidia of the phylum Chloroflexi, most closely related to but distinct from type strains of the species Dehalogenimonas alkenigignens (97.63 % similarity) and Dehalogenimonas lykanthroporepellens (95.05 %). A complete genome sequence determined for strain NSZ-14T revealed a DNA G+C content of 53.96 mol%, which was corroborated by HPLC (54.1±0.2 mol% G+C). Genome-wide comparisons based on average nucleotide identity by orthology and estimated DNA-DNA hybridization values combined with phenotypic and chemotaxonomic traits and phylogenetic analysis indicate that strain NSZ-14T represents a novel species within the genus Dehalogenimonas, for which the name Dehalogenimonas formicexedens sp. nov. is proposed. The type strain is NSZ-14T (=HAMBI 3672T=JCM 19277T=VKM B-3058T). An emended description of Dehalogenimonas alkenigignens is also provided.
Biological treatment processes used to remove and degrade volatile organic compounds (VOCs) from contaminated gases emitted by industrial operations or waste treatment processes are almost always ...subjected to transient loading conditions because of the inherently unsteady-state nature of contaminant generating processes. In the study presented here, a laboratory-scale biofilter populated by a mixed culture of fungi was used to study the transient response to various periods of no contaminant loading in a system treating a model waste gas stream containing a mixture of commonly used solvents. The biofilter, packed with cubed polyurethane foam media and operated with an empty bed residence time of 15
s, was supplied with a four-component mixture of
n-butyl acetate, methyl ethyl ketone, methyl propyl ketone, and toluene at target influent concentrations of 124, 50.5, 174, and 44.6
mg/m
3, respectively. This corresponds to a total VOC loading rate of 94.3
g/(m
3
h). Biofilter performance was evaluated over a 94-day period for three loading conditions intended to simulate processes generating contaminated gases only during daytime operation, daytime operation with weekend shutdown periods, and with long term (9-day) shutdown. Results indicate that fungal biofilters can be an effective alternative to conventional abatement technologies for treating solvent contaminated off-gases even under discontinuous loading conditions.
Two strictly anaerobic bacterial strains, designated IP3-3T and SBP-1, were isolated from groundwater contaminated by chlorinated alkanes and alkenes at a Superfund Site located near Baton Rouge, ...Louisiana (USA). Both strains reductively dehalogenate a variety of polychlorinated aliphatic alkanes, including 1,2-dichloroethane, 1,2-dichloropropane, 1,1,2,2-tetrachloroethane, 1,1,2-trichloroethane and 1,2,3-trichloropropane, when provided with hydrogen as the electron donor. To clarify their taxonomic position, strains IP3-3T and SBP-1 were characterized using a polyphasic approach. Both IP3-3T and SBP-1 are mesophilic, non-spore-forming, non-motile and Gram-stain-negative. Cells of both strains are irregular cocci with diameters of 0.4–1.1 µm. Both are resistant to ampicillin and vancomycin. The genomic DNA G+C contents of strains IP3-3T and SBP-1 are 55.5±0.4 and 56.2±0.2 mol% (HPLC), respectively. Major cellular fatty acids include C18 : 1ω9c, C16 : 0, C14 : 0 and C16 : 1ω9c. 16S rRNA gene sequence based phylogenetic analyses indicated that the strains cluster within the phylum Chloroflexi most closely related to but distinct from the species Dehalogenimonas lykanthroporepellens (96.2 % pairwise similarity) and Dehalococcoides mccartyi (90.6 % pairwise similarity). Physiological and chemotaxonomic traits as well as phylogenetic analysis support the conclusion that these strains represent a novel species within the genus Dehalogenimonas for which the name Dehalogenimonas alkenigignens sp. nov. is proposed. The type strain is IP3-3T ( = JCM 17062T = NRRL B-59545T).
Hypophosphatemia is a common and dangerous complication of acute liver failure (ALF) of various etiologies. While various mechanisms for ALF-associated hypophosphatemia have been proposed including ...high phosphate uptake into regenerating hepatocytes, acetaminophen (APAP)-associated hypophosphatemia was linked to renal phosphate wasting, and APAP-induced renal tubular injury was proposed as underlying mechanism. We studied 30 normophosphatemic and 46 hypophosphatemic (serum phosphate < 2.5 mg/dL) patients from the Acute Liver Failure Study Group registry with APAP- or non-APAP-induced ALF. Since kidney injury affects phosphate excretion, patients with elevated serum creatinine (>1.2 mg/dL) were excluded. Maximal amount of renal tubular phosphate reabsorption per filtered volume (TmP/GFR) was calculated from simultaneous serum and urine phosphate and creatinine levels to assess renal phosphate handling. Instead of enhanced renal phosphate reabsorption as would be expected during hypophosphatemia of non-renal causes, serum phosphate was positively correlated with TmP/GFR in both APAP- and non-APAP-induced ALF patients (R2 = 0.66 and 0.46, respectively; both P < 0.0001), indicating renal phosphate wasting. Surprisingly, there was no evidence of kidney damage based on urinary markers including neutrophil gelatinase-associated lipocalin and cystatin C even in the APAP group. Additionally, there was no evidence that the known serum phosphatonins parathyroid hormone, fibroblast growth factor 23, and α-Klotho contribute to the observed hypophosphatemia. We conclude that the observed hypophosphatemia with renal phosphate wasting in both APAP- and non-APAP-mediated ALF is likely the result of renal tubular phosphate leak from yet-to-be identified factor(s) with no evidence for proximal tubular damage or contribution of known phosphatonins.
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