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Low ph tolerance

Andrea Cecilia Origone, Silvana María Del Mónaco, José Ricardo Ávila, Melisa González Flores, María Eugenia Rodríguez, Christian Ariel Lopes
AIMS: Evaluating the winemaking stress tolerance of a set of both S. eubayanus and S. uvarum strains from diverse Patagonian habitats. METHODS AND RESULTS: Yeast strains growth was analysed under increasing ethanol concentrations; all of them were able to grow until 8% v/v ethanol. The effect of different temperature and pH conditions as well as at SO2 and hexose concentrations was evaluated by means of a Central Composite Experimental Design. Only two S. uvarum strains (NPCC 1289 and 1321) were able to grow in most stress conditions...
May 24, 2017: Journal of Applied Microbiology
Xue Qiang Zhao, Xue Min Bao, Chao Wang, Zuo Yi Xiao, Zhen Min Hu, Chun Li Zheng, Ren Fang Shen
Aluminum (Al) is ubiquitous and toxic to microbes. High Al(3+) concentration and low pH are two key factors responsible for Al toxicity, but our present results contradict this idea. Here, an Al-tolerant yeast strain Rhodotorula taiwanensis RS1 was incubated in glucose media containing Al with a continuous pH gradient from pH 3.1-4.2. The cells became more sensitive to Al and accumulated more Al when pH increased. Calculations using an electrostatic model Speciation Gouy Chapman Stern indicated that, the increased Al sensitivity of cells was associated with AlOH(2+) and Al(OH) 2(+) rather than Al(3+)...
May 24, 2017: Archives of Microbiology
Mireia Mallandrich, Francisco Fernández-Campos, Beatriz Clares, Lyda Halbaut, Cristina Alonso, Luisa Coderch, Maria L Garduño-Ramírez, Berenice Andrade, Alfonso Del Pozo, Majella E Lane, Ana C Calpena
PURPOSE: In order to obtain dermal vehicles of ketorolac tromethamine (KT) for the local treatment of inflammation and restrict undesirable side effects of systemic levels hydrogels (HGs) of poloxamer and carbomer were developed. METHODS: KT poloxamer based HG (KT-P407-HG) and KT carbomer based HG (KT-C940-HG) were elaborated and characterized in terms of swelling, degradation, porosity, rheology, stability, in vitro release, ex vivo permeation and distribution skin layers...
May 24, 2017: Pharmaceutical Research
Chia-Wei Wu, Thomas Spike, Dawn M Klingeman, Miguel Rodriguez, Virgil R Bremer, Steven D Brown
Microorganisms are key components for plant biomass breakdown within rumen environments. Fibrobacter succinogenes have been identified as being active and dominant cellulolytic members of the rumen. In this study, F. succinogenes type strain S85 was adapted for steady state growth in continuous culture at pH 5.75 and confirmed to grow in the range of pH 5.60-5.65, which is lower than has been reported previously. Wild type and acid tolerant strains digested corn stover with equal efficiency in batch culture at low pH...
May 23, 2017: Scientific Reports
Zhu Chen, Caixia Wan
This study aimed at developing low-cost, robust non-sterile fermentation processes for microbial lipid production from lignocellulose-derived sugars. Three representative oleaginous yeasts, Lipomyces tetrasporus (NRRL Y-11562), Rhodotorula toruloides (NRRL Y-1091), and Yarrowia lipolytica (NRRL YB-437), were tested for lipid production via non-sterile fermentation. Under optimal non-sterile conditions, all the tested strains had good performance on salt tolerance and lipid production. L. tetrasporus (NRRL Y-11562) gave the highest lipid titer of 12...
May 20, 2017: Applied Biochemistry and Biotechnology
Alexandra Fumasoli, Helmut Buergmann, David G Weissbrodt, George F Wells, Karin Beck, Joachim Mohn, Eberhard Morgenroth, Kai M Udert
Ammonia oxidation decreases the pH in wastewaters where the alkalinity is limited relative to the total ammonia. The activity of ammonia oxidizing bacteria (AOB), however, typically decreases with pH and often ceases completely in slightly acidic wastewaters. Nevertheless, low pH nitrification has been reported in reactors treating human urine, but it is not clear which organisms are involved. In this study, we followed the population dynamics of ammonia oxidizing organisms and reactor performance in synthetic, synthetic fully hydrolysed urine as the pH decreased over time in response to a decrease in the loading rate...
May 16, 2017: Environmental Science & Technology
Guo Mingxin, Zheng Ling, Zhao Xusheng
Iron is essential for growth and development of rice, which is able to take up Fe(3+)-phytosiderophore, Fe(2+)-nicotianamine and free Fe(2+). Researchers have uncovered key molecular components including transporters, enzymes, and chelators involved in iron uptake and translocation, as well as factors regulating the expression of these genes in rice. Manipulation of these molecular components has produced transgenic rice with enhanced tolerance to alkaline stress on calcareous soils with low-Fe availability due to high soil pH...
May 20, 2017: Yi Chuan, Hereditas
Venkatachalam Narayanan, Jenny Schelin, Marie Gorwa-Grauslund, Ed Wj van Niel, Magnus Carlquist
BACKGROUND: Production of second-generation bioethanol and other bulk chemicals by yeast fermentation requires cells that tolerate inhibitory lignocellulosic compounds at low pH. Saccharomyces cerevisiae displays high plasticity with regard to inhibitor tolerance, and adaptation of cell populations to process conditions is essential for reaching efficient and robust fermentations. RESULTS: In this study, we assessed responses of isogenic yeast cell populations in different physiological states to combinations of acetic acid, vanillin and furfural at low pH...
2017: Biotechnology for Biofuels
Jose Manuel Carbajo, Francisco Maraver
Sulphurous mineral waters have been traditionally used in medical hydrology as treatment for skin, respiratory, and musculoskeletal disorders. However, driven by recent intense research efforts, topical treatments are starting to show benefits for pulmonary hypertension, arterial hypertension, atherosclerosis, ischemia-reperfusion injury, heart failure, peptic ulcer, and acute and chronic inflammatory diseases. The beneficial effects of sulphurous mineral waters, sulphurous mud, or peloids made from sulphurous mineral water have been attributed to the presence of sulphur mainly in the form of hydrogen sulphide...
2017: Evidence-based Complementary and Alternative Medicine: ECAM
Akinori Matsushika, Toshihiro Suzuki, Tetsuya Goshima, Tamotsu Hoshino
We previously showed that overexpression of IoGAS1, which was isolated from the multiple stress-tolerant yeast Issatchenkia orientalis, endows Saccharomyces cerevisiae cells with the ability to grow and ferment under acidic and high-salt conditions. The deduced amino acid sequence of the IoGAS1 gene product exhibits 60% identity with the S. cerevisiae Gas1 protein, a glycosylphosphatidylinositol-anchored protein essential for maintaining cell wall integrity. However, the functional roles of ScGAS1 in stress tolerance and pH regulation remain unclear...
May 2, 2017: Journal of Bioscience and Bioengineering
Hao Ji, Xinyao Lu, Hong Zong, Bin Zhuge
The tolerant yeast Candida glycerinogenes, with high D-xylonate and low-pH tolerances, was used as the host for D-xylonate production at low pH in this study. A low-pH inducible promoter, pGUKd, was engineered using the core promoter of the glyceraldehyde-3-phosphate dehydrogenase gene (pGAP) combined with the upstream activating sequence of the promoter of the guanylate kinase gene (pGUK1) that had substituted pH-responsive TF binding sites. The recombinant cells that expressed GFP from the hybrid promoter pGUKd displayed dramatically increased fluorescence intensity at pH 2...
May 4, 2017: Bioengineered
Amin Tahoun, Hisayoshi Masutani, Hanem El-Sharkawy, Trudi Gillespie, Ryo P Honda, Kazuo Kuwata, Mizuho Inagaki, Tomio Yabe, Izumi Nomura, Tohru Suzuki
BACKGROUND: Bifidobacterium longum 105-A produces markedly high amounts of capsular polysaccharides (CPS) and exopolysaccharides (EPS) that should play distinct roles in bacterial-host interactions. To identify the biological function of B. longum 105-A CPS/EPS, we carried out an informatics survey of the genome and identified the EPS-encoding genetic locus of B. longum 105-A that is responsible for the production of CPS/EPS. The role of CPS/EPS in the adaptation to gut tract environment and bacteria-gut cell interactions was investigated using the ΔcpsD mutant...
2017: Gut Pathogens
Matthew Hum, Marlene Dytoc
BACKGROUND: Genitourinary syndrome of menopause (GSM) is a debilitating condition caused by hypoestrogenism that presents with vaginal dryness and dyspareunia as well as other genital, sexual, and urinary symptoms. Previously known as atrophic vaginitis, the term GSM is now used. OBJECTIVE: To help familiarise dermatologists with diagnosing and managing GSM. METHODS: In total, 218 articles were identified and reviewed by 2 independent authors using PubMed...
April 1, 2017: Journal of Cutaneous Medicine and Surgery
Lu-Nan Zhang, Si-Heng Li, Hua-Qiao Tan, Shifa Ullah Khan, Yuan-Yuan Ma, Hong-Ying Zang, Yong-Hui Wang, Yang-Guang Li
During the exploration of highly efficient noble-metal-free electrocatalysts for the hydrogen evolution reaction (HER), a promising and challenging strategy is to fabricate composite nanocatalysts by finely tuning metal and/or nonmetal element components. Herein, we report a new HER electrocatalyst, which is composed of molybdenum phosphide and molybdenum carbide composite nanoparticles (NPs) coated by few-layer N-doped graphitic carbon shells (denoted as MoP/Mo2C@C). Such a new combination mode of electrocatalysts is realized by a one-step annealing route with the mixture of a Mo/P-based polyoxometalate (POM) and dicyandiamide...
May 3, 2017: ACS Applied Materials & Interfaces
Nohra Park, Saemee Song, Garam Choi, Kyung Ku Jang, Inseong Jo, Sang Ho Choi, Nam-Chul Ha
The transcriptional activator AphB has been implicated in acid resistance and pathogenesis in the food borne pathogens Vibrio vulnificus and Vibrio cholerae. To date, the full-length AphB crystal structure of V. cholerae has been determined and characterized by a tetrameric assembly of AphB consisting of a DNA binding domain and a regulatory domain (RD). Although acidic pH and low oxygen tension might be involved in the activation of AphB, it remains unknown which ligand or stimulus activates AphB at the molecular level...
April 2017: Molecules and Cells
Elleke F Bosma, Jochen Forster, Alex Toftgaard Nielsen
This review discusses opportunities and bottlenecks for cell factory development of Lactic Acid Bacteria (LAB), with an emphasis on lactobacilli and pediococci, their metabolism and genetic tools. In order to enable economically feasible bio-based production of chemicals and fuels in a biorefinery, the choice of product, substrate and production organism is important. Currently, the most frequently used production hosts include Escherichia coli and Saccharomyces cerevisiae, but promising examples are available of alternative hosts such as LAB...
April 7, 2017: Biotechnology Advances
Baocang Liu, Lili Huo, Zhiqing Gao, Guolei Zhi, Geng Zhang, Jun Zhang
Developing high-performance but low-cost hydrogen evolution reaction (HER) electrocatalysts with superior activity and stability for future sustainable energy conversion technologies is highly desired. Tuning of microstructure, configuration, and chemical composition are paramount to developing effective non-noble electrocatalysts for HER. Herein, a universal "nanocasting" method is reported to construct graphene decorated with uniform ternary (CoP)x -(FeP)1-x (0 ≤ x ≤ 1) nanorods hybrids with different chemical compositions [(CoP)x -(FeP)1-x -NRs/G] as a highly active and durable nonprecious-metal electrocatalyst for the HER...
April 10, 2017: Small
Yi Zhang, Jie Hao, Yan-Qi Zhang, Xiu-Lan Chen, Bin-Bin Xie, Mei Shi, Bai-Cheng Zhou, Yu-Zhong Zhang, Ping-Yi Li
Marine esterases play an important role in marine organic carbon degradation and cycling. Halotolerant esterases from the sea may have good potentials in industrial processes requiring high salts. Although a large number of marine esterases have been characterized, reports on halotolerant esterases are only a few. Here, a fosmid library containing 7,200 clones was constructed from a deep-sea sediment sample from the South China Sea. A gene H8 encoding an esterase was identified from this library by functional screening and expressed in Escherichia coli...
2017: Frontiers in Microbiology
Xinhao Yan, Jin Ju Kim, Hye Sun Jeong, Yu Kyung Moon, Yoon Kyung Cho, Soyeon Ahn, Sang Beom Jun, Hakwon Kim, Youngmin You
The study of the zinc biology requires molecular probes with proper zinc affinity. We developed a low-affinity zinc probe (HBO-ACR) based on an azacrown ether (ACR) and an 2-(2-hydroxyphenyl)benzoxazole (HBO) fluorophore. This probe design imposed positive charge in the vicinity of a zinc coordination center, which enabled fluorescence turn-on responses to high levels of zinc without being affected by the pH and the presence of other transition-metal ions. Steady-state and transient photophysical investigations suggested that such a high tolerance benefits from orchestrated actions of proton-induced nonradiative and zinc-induced radiative control...
April 5, 2017: Inorganic Chemistry
Zhaoming Zheng, Jun Li, Jing Ma, Jia Du, Fan Wang, Wei Bian, Yanzhuo Zhang, Baihang Zhao
The aim of the present work was to evaluate the anaerobic ammonium oxidation (anammox) activity of simultaneous partial nitrification, anammox and denitrification (SNAD) biofilm with different substrate concentrations and pH values. Kaldnes rings taken from the SNAD biofilm reactor were incubated in batch tests to determine the anammox activity. Haldane model was applied to investigate the ammonium inhibition on anammox process. As for nitrite inhibition, the NH4(+)-N removal rate of anammox process remained 87...
March 2017: Journal of Environmental Sciences (China)
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