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pH homeostasis

Antonino Baez, Joseph Shiloach
The damaging effect of high oxygen concentration on growth of Escherichia coli is well established. Over-oxygenation increases the intracellular concentration of reactive oxygen species (ROS), causing the destruction of the [4Fe-4S] cluster of dehydratases and limiting the biosynthesis of both branched-chain amino acids and nicotinamide adenine dinucleotide. A key enzyme that reduces the damaging effect of superoxide is superoxide dismutase (SOD). Its transcriptional regulation is controlled by global transcription regulators that respond to changes in oxygen and iron concentrations and pH...
October 18, 2016: Antonie Van Leeuwenhoek
Yongkang Yue, Fangjun Huo, Songyi Lee, Caixia Yin, Juyoung Yoon
Intracellular pH values are some of the most important factors that govern biological processes and the acid-base homeostasis in cells, body fluids and organs sustains the normal operations of the body. Subcellular organelles including the acidic lysosomes and the alkalescent mitochondria undergo various processes such as intracellular digestion, ATP production and apoptosis. Due to their precise imaging capabilities, fluorescent probes have attracted great attention for the illustration of pH modulated processes...
October 19, 2016: Analyst
Catherine Duport, Michel Jobin, Philippe Schmitt
Bacillus cereus is a food-borne pathogen that causes diarrheal disease in humans. After ingestion, B. cereus experiences in the human gastro-intestinal tract abiotic physical variables encountered in food, such as acidic pH in the stomach and changing oxygen conditions in the human intestine. B. cereus responds to environmental changing conditions (stress) by reversibly adjusting its physiology to maximize resource utilization while maintaining structural and genetic integrity by repairing and minimizing damage to cellular infrastructure...
2016: Frontiers in Microbiology
Shuitu Feng, Zhigao Zheng, Lihua Feng, Lihong Yang, Zuhong Chen, Yubiao Lin, Yingqin Gao, Yide Chen
The cancer stem cell (CSC) model suggests that a small subset of cancer cells possess stem cell properties and plays a crucial role in tumor initiation, metastasis and resistance to anticancer therapy. Exploration of the specific therapies targeting at CSCs has been a crucial issue in antitumor research. Gastric cancer (GC) cells often exist in an ischemic microenvironment with acidic conditions in vivo, thus maintenance of cellular pH homeostasis is important for the survival and function of GC cells. Proton pump inhibitors (PPIs) may prevent intracellular proton extrusions which consequently reduce cancer cell survival under acidic conditions...
October 7, 2016: Oncology Reports
Kumar Abhishek, Abul Hasan Sardar, Sushmita Das, Ashish Kumar, Ayan Kumar Ghosh, Ruby Singh, Savita Saini, Abhishek Mandal, Sudha Verma, Ajay Kumar, Bidyut Purkait, Manas Ranjan Dikhit, Pradeep Das
Leishmania donovani transformation to amastigote from promastigote during mammalian host infection; displays the immense adaptability of the parasite to survive under stress. Induction of translation initiation factor 2-alpha (eIF2α) phosphorylation by stress specific eIF2α kinases is the basic stress perceiving signal in eukaryotes to counter stress. Here, we demonstrate that elevated temperature and acidic pH; induces phosphorylation of Leishmania donovani eIF2α (LdeIF2α). The in-vitro inhibition experiments suggest interference of LdeIF2α phosphorylation under elevated temperature and acidic pH debilitates parasite differentiation and reduces parasite viability (P< 0...
October 10, 2016: Molecular and Cellular Biology
Vinciane Saint-Criq, Michael A Gray
Salt and fluid absorption and secretion are two processes that are fundamental to epithelial function and whole body fluid homeostasis, and as such are tightly regulated in epithelial tissues. The CFTR anion channel plays a major role in regulating both secretion and absorption in a diverse range of epithelial tissues, including the airways, the GI and reproductive tracts, sweat and salivary glands. It is not surprising then that defects in CFTR function are linked to disease, including life-threatening secretory diarrhoeas, such as cholera, as well as the inherited disease, cystic fibrosis (CF), one of the most common life-limiting genetic diseases in Caucasian populations...
October 6, 2016: Cellular and Molecular Life Sciences: CMLS
Todd A Cameron, Nicholas R De Lay
: Gene regulation by base-pairing between small non-coding RNAs (sRNAs) and their mRNA targets is an important mechanism that allows bacteria to maintain homeostasis and respond to dynamic environments. In Gram negative bacteria, sRNA pairing and regulation is mediated by several RNA-binding proteins, including the sRNA chaperone Hfq and polynucleotide phosphorylase (PNPase). PNPase and its homolog RNase PH together represent the two 3' -5' phosphorolytic exoribonucleases found in Escherichia coli; however, a role for RNase PH in sRNA regulation has not yet been explored and reported...
October 3, 2016: Journal of Bacteriology
D P Froman
Four premises for rooster sperm preservation were outlined previously. Understanding mitochondrial Ca cycling in terms of whole-cell Ca flux was one premise. The present work tested the hypothesis that sperm mitochondria can be damaged by intracellular as well as extracellular Ca. Sperm were washed by centrifugation through 12% (wt/vol) Sperm were washed by centrifugation through 12%(at/vol) Accudenz to procure sperm at a physiological concentration within a chemically-defined suspension. Five solutions were tested...
August 2016: Journal of Animal Science
Ilkka Kronholm, Hanna Johannesson, Tarmo Ketola
Phenotypic plasticity is the ability of a genotype to produce different phenotypes under different environmental or developmental conditions. Phenotypic plasticity is an ubiquitous feature of living organisms and is typically based on variable patterns of gene expression. However, the mechanisms by which gene expression is influenced and regulated during plastic responses are poorly understood in most organisms. While modifications to DNA and histone proteins have been implicated as likely candidates for generating and regulating phenotypic plasticity, specific details of each modification and its mode of operation have remained largely unknown...
September 30, 2016: G3: Genes—Genomes—Genetics
J Zimmer, T Takahashi, A D Hofmann, Prem Puri
PURPOSE: High mortality and morbidity in infants born with congenital diaphragmatic hernia (CDH) are attributed to pulmonary hypoplasia and pulmonary hypertension (PH). Forkhead box (Fox) transcription factors are known to be crucial for cell proliferation and homeostasis. FoxF1 is essential for lung morphogenesis, vascular development, and endothelial proliferation. Mutations in FoxF1 and also the Fox family member FoxC2 have been identified in neonates with PH. In human and experimental models of arterial PH, the Fox protein FoxO1 was found to be downregulated...
September 23, 2016: Pediatric Surgery International
Dongni Yan, Xiaobao Lin, Yanli Qi, Hui Liu, Xiulai Chen, Liming Liu, Jian Chen
The asexual facultative aerobic haploid yeast Candida glabrata is widely used in the industrial production of various organic acids. To elucidate the physiological function of the transcription factor CgCrz1p and its role in tolerance to acid stress we deleted or overexpressed the corresponding gene CgCRZ1 Deletion of CgCRZ1 resulted in a 60% decrease in dry cell weight (DCW) and a 50% drop in cell viability compared to the wild type at pH 2.0. Expression of lipid metabolism-associated genes was also significantly down-regulated...
September 23, 2016: Applied and Environmental Microbiology
Hao Zhu, Jiangli Fan, Jianjun Du, Xiaojun Peng
Fluorescent probes have become powerful tools in biosensing and bioimaging because of their high sensitivity, specificity, fast response, and technical simplicity. In the last decades, researchers have made remarkable progress in developing fluorescent probes that respond to changes in microenvironments (e.g., pH, viscosity, and polarity) or quantities of biomolecules of interest (e.g., ions, reactive oxygen species, and enzymes). All of these analytes are specialized to carry out vital functions and are linked to serious disorders in distinct subcellular organelles...
October 18, 2016: Accounts of Chemical Research
George E Barreto
In the brain, the astrocentric view has increasingly changed in the past few years. The classical and old view of astrocytes as "just supporting cells" has assigned these cells some functions to help neurons maintain their homeostasis. This neuronal supportive function of astrocytes includes maintenance of ion and extracellular pH equilibrium, neuroendocrine signaling, metabolic support, clearance of glutamate and other neurotransmitters, and antioxidant protection. However, recent findings have shed some light on the new roles, some controversial though, performed by astrocytes that might change our view about the central nervous system functioning...
September 2016: Progress in Neurobiology
Angela Scala, Silvana Ficarra, Annamaria Russo, Davide Barreca, Elena Giunta, Antonio Galtieri, Giovanni Grassi, Ester Tellone
We have recently proposed a new erythrocyte-based model of study to predict the antiproliferative effects of selected heterocyclic scaffolds. Starting from the metabolic similarity between erythrocytes and cancer cells, we have demonstrated how the metabolic derangement induced by an indolone-based compound (DPIT) could be related to its antiproliferative effects. In order to prove the validity of our biochemical approach, in the present study the effects on erythrocyte functionality of its chemical precursor (PID), whose synthesis we reported, were investigated...
2016: Oxidative Medicine and Cellular Longevity
Bradley A Webb, Katharine A White, Bree K Grillo-Hill, André Schönichen, Changhoon Choi, Diane L Barber
The Na-H exchanger NHE1 contributes to intracellular pH (pHi) homeostasis in normal cells and the constitutively increased pHi in cancer. NHE1 activity is allosterically regulated by intracellular protons, with greater activity at lower pHi. However, the molecular mechanism for pH-dependent NHE1 activity remains incompletely resolved. We report that an evolutionarily conserved cluster of histidine residues located in the C-terminal cytoplasmic domain between two phosphatidylinositol 4,5-bisphosphate-binding sites (PI(4,5)P2) of NHE1 confers pH-dependent PI(4,5)P2-binding and regulates NHE1 activity...
September 20, 2016: Journal of Biological Chemistry
Feng Qiu, Adam Chamberlin, Briana M Watkins, Alina Ionescu, Marta Elena Perez, Rene Barro-Soria, Carlos González, Sergei Y Noskov, H Peter Larsson
Voltage-gated proton (Hv1) channels are involved in many physiological processes, such as pH homeostasis and the innate immune response. Zn(2+) is an important physiological inhibitor of Hv1. Sperm cells are quiescent in the male reproductive system due to Zn(2+) inhibition of Hv1 channels, but become active once introduced into the low-Zn(2+)-concentration environment of the female reproductive tract. How Zn(2+) inhibits Hv1 is not completely understood. In this study, we use the voltage clamp fluorometry technique to identify the molecular mechanism of Zn(2+) inhibition of Hv1...
October 4, 2016: Proceedings of the National Academy of Sciences of the United States of America
Adam J Rossano, Akira Kato, Karyl I Minard, Michael F Romero, Gregory T Macleod
Neuronal activity can result in transient acidification of presynaptic terminals and such shifts in cytosolic pH (pHcyto ) likely influence mechanisms underlying forms of synaptic plasticity with a presynaptic locus. As neuronal activity drives acid loading in presynaptic terminals we hypothesized that the same activity might drive acid efflux mechanisms to maintain pHcyto homeostasis. To better understand the integration of neuronal activity and pHcyto regulation we investigated the acid extrusion mechanisms at Drosophila glutamatergic motorneuron terminals...
September 19, 2016: Journal of Physiology
Kuljit Singh, Krishn Pratap Singh, Asif Equbal, Shashi S Suman, Amir Zaidi, Gaurav Garg, Krishna Pandey, Pradeep Das, Vahab Ali
Leishmania possess a unique trypanothione redox metabolism with undebated roles in protection from oxidative damage and drug resistance. The biosynthesis of trypanothione depends on l-cysteine bioavailability which is regulated by cysteine biosynthesis pathway. The de novo cysteine biosynthesis pathway is comprised of serine O-acetyltransferase (SAT) and cysteine synthase (CS) enzymes which sequentially mediate two consecutive steps of cysteine biosynthesis, and is absent in mammalian host. However, despite the apparent dependency of redox metabolism on cysteine biosynthesis pathway, the role of SAT and CS in redox homeostasis has been unexplored in Leishmania parasites...
September 13, 2016: Biochimie
Robin A Felder, Pedro A Jose, Peng Xu, John J Gildea
The sodium bicarbonate cotransporter (NBCe2, aka NBC4) was originally isolated from the human testis and heart (Pushkin et al. IUBMB Life 50:13-19, 2000). Subsequently, NBCe2 was found in diverse locations where it plays a role in regulating sodium and bicarbonate transport, influencing intracellular, extracellular, interstitial, and ultimately plasma pH (Boron et al. J Exp Biol. 212:1697-1706, 2009; Parker and Boron, Physiol Rev. 93:803-959, 2013; Romero et al. Mol Asp Med. 34:159-182, 2013). NBCe2 is located in human and rodent renal-collecting duct and proximal tubule...
September 2016: Current Hypertension Reports
Moiz A Ansari, Zeeshan Fatima, Saif Hameed
This study explored the antifungal potential of perillyl alcohol (PA), a natural monoterpene alcohol, against most prevalent human fungal pathogen C. albicans, its clinical isolates and four non-albicans species of Candida. To resolve the potential mechanisms, we used whole genome transcriptome analyses of PA treated Candida cells to examine the affected cellular circuitry of this pathogen. The transcriptome data revealed a link between calcineurin signaling and PA as among the several categories of PA responsive genes the down regulation of calcineurin signaling gene CNB1 was noteworthy which was also confirmed by both molecular docking and susceptibility assays...
2016: PloS One
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