scholarly journals Mechanisms of Cholera Agent Persistence under Varying Osmolarity Conditions

2016 ◽  
Vol 21 (4) ◽  
pp. 225-233
Author(s):  
Svetlana P. Zadnova ◽  
N. A Plekhanov ◽  
N. I Smirnova
Keyword(s):  
Sodium Chloride ◽  
Chloride Concentration ◽  
Chloride Content ◽  
Transport Systems ◽  
Expression Of Genes ◽  
Nacl Concentration ◽  
Genes Encoding ◽  
Transcription Regulators ◽  
Mechanisms Of Adaptation ◽  
The Impact

During the lifecycle cholera agent, being human pathogen and natural reservoir inhabitant, is constantly exposed to varying osmolarity environments, induced by different sodium chloride content. However, Vibrio cholerae has created the mechanisms providingfor adaptation to changes of living surroundings. The review covers the data on the impact of NaCl on the survivability of toxigenic V. cholerae strains, and information on mechanisms of adaptation to varying osmolarity. It is demonstrated that at low NaCl contents expression of genes, necessary for cell wall formation and cell growth is elevated; under high NaCl concentration conditions for transcription of genes, encoding transport systems, removing sodium ions, and also responsible for biosynthesis of osmoprotectors, are increased. There is discussed the role of two transcription regulators, CosR and OscR, cooperatively altering gene expression in accordance with particular environmental osmolarity. Further studies into the mechanisms of V. cholerae adaptation to changes of sodium chloride concentration will extend the knowledge about biology and ecology of the pathogen.

TURBIDITY OF SUSPENSIONS AND MORPHOLOGY OF RED HALOPHILIC BACTERIA AS INFLUENCED BY SODIUM CHLORIDE CONCENTRATION

1960 ◽  
Vol 6 (5) ◽  
pp. 535-543 ◽  
Author(s):  
Dinah Abram ◽  
N. E. Gibbons
Keyword(s):  
Sodium Chloride ◽  
Salt Concentration ◽  
Morphological Changes ◽  
Halophilic Bacteria ◽  
Chloride Concentration ◽  
Chloride Content ◽  
Wall Structure ◽  
Abrupt Decrease ◽  
High Sodium ◽  
Rigid Cell Wall

The optical densities of suspensions of cells of Halobacterium cutirubrum, H. halobium, or H. salinarium, grown in media containing 4.5 M sodium chloride, increase as the salt concentration of the suspending medium decreases, until a maximum is reached at about 2 M; below this concentration there is an abrupt decrease in optical density. The cells are rod shaped in 4.5 M salt and change, as the salt concentration decreases, through irregular transition forms to spheres; equal numbers of transition forms and spheres are present at the point of maximum turbidity, while spheres predominate at lower salt concentrations. Cells suspended in 3.0 M salt, although slightly swollen, are viable, but viability decreases rapidly with the more drastic changes in morphology at lower salt concentrations. Cells grown in the presence of iron are more resistant to morphological changes but follow the same sequence. Cells "fixed" with formaldehyde, at any point in the sequence, act as osmometers and do not rupture in distilled water although their volume increases 10–14 times. The results indicate that the red halophilic rods require a high sodium chloride content in their growth or suspending medium to maintain a rigid cell wall structure.

scholarly journals Characterization of Virus Adsorption by Using DEAE-Sepharose and Octyl-Sepharose

2002 ◽  
Vol 68 (8) ◽  
pp. 3965-3968 ◽  
Author(s):  
Patricia A. Shields ◽  
Samuel R. Farrah
Keyword(s):  
Sodium Chloride ◽  
Electrostatic Interactions ◽  
Hydrophobic Interactions ◽  
Chloride Concentration ◽  
Sodium Chloride Concentration ◽  
Virus Adsorption ◽  
Nacl Concentration

ABSTRACT Viruses were characterized by their adsorption to DEAE-Sepharose or by their elution from octyl-Sepharose by using buffered solutions of sodium chloride with different ionic strengths. Viruses whose adsorption to DEAE-Sepharose was reduced most rapidly by an increase in the sodium chloride concentration were considered to have the weakest electrostatic interactions with the solids; these viruses included MS2, E1, and φX174. Viruses whose adsorption to DEAE-Sepharose was reduced least rapidly were considered to have the strongest electrostatic interactions with the column; these viruses included P1, T4, T2, and E5. All of the viruses studied adsorbed to octyl-Sepharose in the presence of 4 M NaCl. Viruses that were eluted most rapidly following a decrease in the concentration of NaCl were considered to have the weakest hydrophobic interactions with the column; these viruses included φX174, CB4, and E1. Viruses that were eluted least rapidly from the columns after the NaCl concentration was decreased were considered to have the strongest hydrophobic interactions with the column; these viruses included f2, MS2, and E5.

scholarly journals Role of hyaluronan in regulating self-renewal and osteogenic differentiation of mesenchymal stromal cells and pre-osteoblasts

2020 ◽  
Vol 24 (11) ◽  
pp. 3923-3937
Author(s):  
Maria B. Asparuhova ◽  
Vivianne Chappuis ◽  
Alexandra Stähli ◽  
Daniel Buser ◽  
Anton Sculean
Keyword(s):  
Growth Factor ◽  
Osteogenic Differentiation ◽  
Bone Matrix ◽  
Osteogenic Potential ◽  
Differentiation Markers ◽  
Self Renewal ◽  
Downstream Signaling ◽  
Expression Of Genes ◽  
Genes Encoding ◽  
The Impact

Abstract Objectives The aim of the study was to investigate the impact of two hyaluronan (HA) formulations on the osteogenic potential of osteoblast precursors. Materials and methods Proliferation rates of HA-treated mesenchymal stromal ST2 and pre-osteoblastic MC3T3-E1 cells were determined by 5-bromo-20-deoxyuridine (BrdU) assay. Expression of genes encoding osteogenic differentiation markers, critical growth, and stemness factors as well as activation of downstream signaling pathways in the HA-treated cells were analyzed by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and immunoblot techniques. Results The investigated HAs strongly stimulated the growth of the osteoprogenitor lines and enhanced the expression of genes encoding bone matrix proteins. However, expression of late osteogenic differentiation markers was significantly inhibited, accompanied by decreased bone morphogenetic protein (BMP) signaling. The expression of genes encoding transforming growth factor-β1 (TGF-β1) and fibroblast growth factor-1 (FGF-1) as well as the phosphorylation of the downstream signaling molecules Smad2 and Erk1/2 were enhanced upon HA treatment. We observed significant upregulation of the transcription factor Sox2 and its direct transcription targets and critical stemness genes, Yap1 and Bmi1, in HA-treated cells. Moreover, prominent targets of the canonical Wnt signaling pathway showed reduced expression, whereas inhibitors of the pathway were considerably upregulated. We detected decrease of active β-catenin levels in HA-treated cells due to β-catenin being phosphorylated and, thus, targeted for degradation. Conclusions HA strongly induces the growth of osteoprogenitors and maintains their stemness, thus potentially regulating the balance between self-renewal and differentiation during bone regeneration following reconstructive oral surgeries. Clinical relevance Addition of HA to deficient bone or bony defects during implant or reconstructive periodontal surgeries may be a viable approach for expanding adult stem cells without losing their replicative and differentiation capabilities.

Using muscle gene expression to estimate triacylglyceride deposition, and relative contributions of fatty acid synthesis and fatty acid import in intramuscular fat in cattle

2014 ◽  
Vol 54 (9) ◽  
pp. 1436 ◽  
Author(s):  
B. P. Dalrymple ◽  
B. Guo ◽  
G. H. Zhou ◽  
W. Zhang
Keyword(s):  
Gene Expression ◽  
Fatty Acid ◽  
De Novo ◽  
Acid Synthesis ◽  
Intramuscular Fat ◽  
Muscle Gene Expression ◽  
Expression Of Genes ◽  
Genes Encoding ◽  
Muscle Gene ◽  
The Impact

Intramuscular fat content (IMF%) in cattle influences the value of individual animals, especially for higher marbling markets. IMF is triacylglyceride (TAG) in lipid droplets in the intramuscular adipocytes. However, there are many different pathways from feed intake to the final common process of TAG synthesis and storage as IMF. To evaluate the relative importance of different pathways we compared changes in the expression of genes encoding proteins involved in the TAG and fatty acid (FA) synthesis pathways in the longissimus muscle of Piedmontese × Hereford (P×H) and Wagyu × Hereford (W×H) crosses. Based on these changes we have estimated the relative contributions of FA synthesised de novo in the intramuscular adipocyte and the uptake of circulating FA (both free and from TAG), from the diet or synthesised de novo in other tissues, to TAG deposition as IMF. We have analysed the impact of different developmental times and different diets on these processes. Increased de novo FA synthesis in intramuscular adipocytes appeared to contribute more than increased FA uptake from circulation to the additional TAG deposition in W×H compared with P×H cattle between 12 and 25 months (forage diet). Changing diet from forage to concentrate appeared to increase the importance of FA uptake from circulation relative to de novo FA synthesis for TAG synthesis in intramuscular adipocytes. These results are consistent with the literature based on analysis of lipid composition. Gene expression appears to provide a simple assay for identification of the source of FA for the deposition of IMF.

scholarly journals ANALYSIS OF THE EXPRESSION OF BIRCH STRESS TOLERANCE GENES UNDER THE INFLUENCE OF DROUGHT IN THE CENTRAL BLACK EARTH REGION

2020 ◽  
Vol 10 (2) ◽  
pp. 23-34
Author(s):  
Tat'yana Grodeckaya ◽  
Petr Evlakov ◽  
Igor Isakov
Keyword(s):  
Abiotic Stress ◽  
Deciduous Forest ◽  
Rna Isolation ◽  
Phenylpropanoid Pathway ◽  
Resistance Mechanisms ◽  
Drought Period ◽  
Cell Defense ◽  
Expression Of Genes ◽  
Genes Encoding ◽  
The Impact

Birch is one of the main deciduous forest-forming species in the European part of Russia, but the impact of stress (in particular, drought) greatly limits its distribution. In this regard, it seems relevant to identify resistance mechanisms in order to select promising genotypes for their further reproduction. The aim of this work is to identify drought-tolerant genotypes of European birch (B. pendula Roth.), pubescent birch (B. pubescens Ehrh.) аnd their hybrids. For the study, we have taken samples of birch at the age of 26 years, which remained viable after the droughts of 2010 and 2013. Birch leaves have been selected in the third decade of June 2019 to analyze drought resistance. Leaves of birch, selected during the period with optimal conditions of air temperature and precipitation, have been used as control ones. A modified CTAB method has been proposed for RNA isolation. We studied the expression of genes encoding proteins involved in the activation of cell defense pathways under the influence of abiotic stress (pal, PR-1, PR-10, lea8, DREB2) during the drought period (June 2019). A study of the expression of genes encoding proteins of metabolic pathways that are activated in response to abiotic stress (phenylpropanoid pathway) associated with the pathogenesis of proteins (PR1 and PR10), transcription factors (DREB2), and late embryogenesis proteins (LEA) has been made. As a result of the effects of drought, a significant increase in the expression of pal, PR-1, PR-10 and DREB2 genes has been detected in the analyzed samples. At the same time, changes in lea8 gene expression were detected for two out of ten genotypes. The largest increase in expression for all five genes is shown for birch samples 29-58 and 233. It indicates the development of adaptive mechanisms in these genotypes and can characterize them as the most stable. The studied genes can be recommended as markers for the analysis of stress resistance in various species of woody plants

scholarly journals Differential Regulation of High-Affinity Phosphate Transport Systems of Mycobacterium smegmatis: Identification of PhnF, a Repressor of the phnDCE Operon

2007 ◽  
Vol 190 (4) ◽  
pp. 1335-1343 ◽  
Author(s):  
Susanne Gebhard ◽  
Gregory M. Cook
Keyword(s):  
Mycobacterium Smegmatis ◽  
Constitutive Expression ◽  
Phosphate Transport ◽  
Phosphate Limitation ◽  
Transport Systems ◽  
New Members ◽  
High Affinity ◽  
Expression Of Genes ◽  
Two Component ◽  
Genes Encoding

ABSTRACT The uptake of phosphate into the cell via high-affinity, phosphate-specific transport systems has been studied with several species of mycobacteria. All of these species have been shown to contain several copies of such transport systems, which are synthesized in response to phosphate limitation. However, the mechanisms leading to the expression of the genes encoding these transporters have not been studied. This study reports on the investigation of the regulation of the pstSCAB and the phnDCE operons of Mycobacterium smegmatis. The phn locus contains an additional gene, phnF, encoding a GntR-like transcriptional regulator. Expression analyses of a phnF deletion mutant demonstrated that PhnF acts as a repressor of the phnDCE operon but does not affect the expression of pstSCAB. The deletion of pstS, which is thought to cause the constitutive expression of genes regulated by the two-component system SenX3-RegX3, led to the constitutive expression of the transcriptional fusions pstS-lacZ, phnD-lacZ, and phnF-lacZ, suggesting that phnDCE and phnF are conceivably new members of the SenX3-RegX3 regulon of M. smegmatis. Two presumptive binding sites for PhnF in the intergenic region between phnD and phnF were identified and shown to be required for the repression of phnD and phnF, respectively. We propose a model in which the transcription of pstSCAB is controlled by the two-component SenX3-RegX3 system, while phnDCE and phnF are subject to dual control by SenX3-RegX3 and PhnF.

scholarly journals How Sodium Chloride Concentration in the Nutrient Solution Influences the Mineral Composition of Tomato Leaves and Fruits

HortScience ◽  
2009 ◽  
Vol 44 (3) ◽  
pp. 707-711 ◽  
Author(s):  
Francesco Giuffrida ◽  
Marianna Martorana ◽  
Cherubino Leonardi
Keyword(s):  
Sodium Chloride ◽  
Nutrient Solution ◽  
Chloride Concentration ◽  
Linear Increase ◽  
Ion Concentration ◽  
High Concentration ◽  
Tomato Plants ◽  
Nacl Concentration ◽  
Electrical Conductivities ◽  
Linear Decline

Tomato plants (Solanum lycopersicum L. cv. Durinta) were grown in an open soilless system to evaluate the effects of sodium chloride (NaCl) concentration in the nutrient solution on the ion compositions in plant tissues. The treatments were defined by a factorial combination of five NaCl concentrations and three leaves position/age and two fruits' position. Seedlings were transplanted in perlite and, 7 days after transplanting, five salinity treatments were imposed by adding 7, 21, 37, 49, or 64 mm of NaCl to the nutrient solutions; the final electrical conductivities were: 2.7, 4.5, 6.0, 7.5, and 8.6 dS·m−1, respectively. Increased salinity in the nutrient solution resulted in a reduction in tomato dry matter (from 534 to 375 g per plant) and in a linear increase in sodium (from 0.37% to 1.39%) and chloride (from 1.75% to 5.73%) in the leaves as well as in the fruit tissues (from 0.08% to 0.26% for sodium and from 0.63% to 1.34% for chloride). Leaf under the first cluster showed higher levels of sodium (+54%) and chloride (+32%) than leaf under the fifth cluster and old leaf accumulated more sodium (+15%) and chloride (+25%) than younger ones. The exposure of the tomato plants to increasing salinity resulted in a linear decline in nitrate (from 1.21% to 0.50%), total nitrogen (from 3.31% to 3.03%), sulphate (from 3.71% to 3.12%), and potassium leaves (from 2.76% to 1.51%); the potassium reduction was more evident in younger leaves than in older ones. All macronutrients, except calcium, decreased in the fruit tissues with increasing NaCl concentration in the nutrient solution. However, for phosphate, the reduction of the ion concentration was evident only in the fruit from the fifth cluster (–35%). The position of the fruit on the plant significantly affected the concentration of ion, which was higher for all determined ions in the fruit of the first truss. The levels of Na+ and Cl– found in the plant tissue seem to confirm the hypothesis that the plant dry biomass reduction may also be traced to the toxicity of these ions as a consequence of this high concentration. On the other hand, although generally influenced by antagonism with sodium and chloride, the amount of main macronutrients did not reach deficiency levels that influenced the growth processes, except in the case of potassium.

scholarly journals Effects of Subinhibitory Concentrations of Antibiotics on Colonization Factor Expression by Moxifloxacin-Susceptible and Moxifloxacin-Resistant Clostridium difficile Strains

2009 ◽  
Vol 53 (12) ◽  
pp. 5155-5162 ◽  
Author(s):  
Cécile Denève ◽  
Sylvie Bouttier ◽  
Bruno Dupuy ◽  
Frédéric Barbut ◽  
Anne Collignon ◽  
...  
Keyword(s):  
Clostridium Difficile ◽  
Fluoroquinolone Resistance ◽  
Reverse Transcription Pcr ◽  
Colonization Factor ◽  
Expression Of Genes ◽  
Genes Encoding ◽  
Resistant Strains ◽  
Subinhibitory Concentrations ◽  
The Impact

ABSTRACT Recent outbreaks of Clostridium difficile infection have been related to the emergence of the NAP1/027 epidemic strain. This strain demonstrates increased virulence and resistance to the C-8-methoxyfluoroquinolones gatifloxacin and moxifloxacin. These antibiotics have been implicated as major C. difficile infection-inducing agents. We investigated by real-time reverse transcription-PCR the impact of subinhibitory concentrations of ampicillin, clindamycin, ofloxacin, and moxifloxacin on the expression of genes encoding three colonization factors, the protease Cwp84, the high-molecular-weight S-layer protein, and the fibronectin-binding protein Fbp68. We have previously shown in six non-NAP1/027 moxifloxacin-susceptible strains that the presence of ampicillin or clindamycin induced an upregulation of these genes, whereas the presence of fluoroquinolones did not. The objective of this study was to analyze the expression of these genes under the same conditions in four NAP1/027 strains, one moxifloxacin susceptible and three moxifloxacin resistant. Two in vitro-selected moxifloxacin-resistant mutants were also analyzed. Moxifloxacin resistance was associated with the Thr82→Ile substitution in GyrA in all but one of the moxifloxacin-resistant strains. The expression of cwp84 and slpA was strongly increased after culture with ampicillin or clindamycin in NAP1/027 strains. Interestingly, after culture with fluoroquinolones, the expression of cwp84 and slpA was only increased in four moxifloxacin-resistant strains, including the NAP1/027 strains and one of the in vitro-selected mutants. The overexpression of cwp84 was correlated with increased production of the protease Cwp84. The historical NAP1/027 moxifloxacin-susceptible strain and its mutant appear to be differently regulated by fluoroquinolones. Overall, fluoroquinolones appear to favor the expression of some colonization factor-encoding genes in resistant C. difficile strains. The fluoroquinolone resistance of the NAP1/027 epidemic strains could be considered an ecological advantage. This could also increase their colonization fitness and promote the infection.

Sodium Chloride and Pathogenic Bacteria in a Vacuum-Packed Minced-Meat Product

1985 ◽  
Vol 48 (2) ◽  
pp. 150-155 ◽  
Author(s):  
H.-J. S. NIELSEN ◽  
P. ZEUTHEN
Keyword(s):  
Sodium Chloride ◽  
Salmonella Enteritidis ◽  
Pathogenic Bacteria ◽  
Storage Temperature ◽  
Meat Product ◽  
Chloride Concentration ◽  
Chloride Content ◽  
Inhibitory Effect ◽  
High Sodium ◽  
Salt Level

Development of Bacillus cereus, Salmonella enteritidis, Salmonella typhimurium and Yersinia enterocolitica in vacuum-packed Bologna-type sausage was highly influenced by sodium chloride level (brine concentrations 3.4, 4.5 and 6.0; 2.8 for salmonellae) with none of the bacteria growing at 6.0%. Growth of Staphylococcus aureus was unaffected even by the highest sodium chloride concentration used. Decreasing the storage temperature accentuated the inhibitory effect of sodium chloride on Y. enterocolitica and B. cereus. Initial numbers decreased slowly or remained static in sausage with a high sodium chloride content, when growth did not occur. At the low salt level, at 2–5°C, only Y. enterocolitica was not inhibited until the sodium chloride content was 4.5% and the storage temperature 2°C. At increased, but not unusual temperature, B. cereus could develop at 4.5% (12°C) and S. aureus at all salt levels (8–15°C).

scholarly journals A genome-wide analysis of Escherichia coli responses to fosfomycin using TraDIS-Xpress reveals novel roles for phosphonate degradation and phosphate transport systems

2020 ◽  
Vol 75 (11) ◽  
pp. 3144-3151 ◽  
Author(s):  
A Keith Turner ◽  
Muhammad Yasir ◽  
Sarah Bastkowski ◽  
Andrea Telatin ◽  
Andrew J Page ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Sugar Metabolism ◽  
Phosphate Transport ◽  
Transport Systems ◽  
Loss Of Function ◽  
Genome Wide Analysis ◽  
Genome Wide ◽  
A Genome ◽  
Genes Encoding ◽  
The Impact

Abstract Background Fosfomycin is an antibiotic that has seen a revival in use due to its unique mechanism of action and efficacy against isolates resistant to many other antibiotics. In Escherichia coli, fosfomycin often selects for loss-of-function mutations within the genes encoding the sugar importers, GlpT and UhpT. There has, however, not been a genome-wide analysis of the basis for fosfomycin susceptibility reported to date. Methods Here we used TraDIS-Xpress, a high-density transposon mutagenesis approach, to assay the role of all genes in E. coli involved in fosfomycin susceptibility. Results The data confirmed known fosfomycin susceptibility mechanisms and identified new ones. The assay was able to identify domains within proteins of importance and revealed essential genes with roles in fosfomycin susceptibility based on expression changes. Novel mechanisms of fosfomycin susceptibility that were identified included those involved in glucose metabolism and phosphonate catabolism (phnC-M), and the phosphate importer, PstSACB. The impact of these genes on fosfomycin susceptibility was validated by measuring the susceptibility of defined inactivation mutants. Conclusions This work reveals a wider set of genes that contribute to fosfomycin susceptibility, including core sugar metabolism genes and two systems involved in phosphate uptake and metabolism previously unrecognized as having a role in fosfomycin susceptibility.

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