Catalase and Superoxide Dismutase: Distribution, Properties, and Physiological Role in Cells of Strict Anaerobes

This review considers the distribution of the main enzymes of antioxidative defense, superoxide dismutase (SOD) and catalase, in various groups of strictly anaerobic microorganisms: bacteria of the genus Clostridium, Bacteroides, sulfate-reducing and acetogenic bacteria, methanogenic archaea, etc. Molecular and biochemical properties of purified Fe-containing SODs, cambialistic SODs, and heme catalases are presented. The physiological role and origin of the enzymes of antioxidative defense in strict anaerobes are discussed. Physiological responses (induction of SOD and catalase) to factors provoking oxidative stress in the cells of strict anaerobes able to maintain viability under aerobic conditions are also considered.     

Physiological Properties of Yeast Cells Grown in the Proteolipid-Supplemented Media

Koji mold proteolipid (PL), a high concentration alcohol-producing factor, promoted yeast growth, and also affected the physiological properties of yeast cells: in the conditions of statical cultures, the cells grown anaerobically in PL-supplemented media showed the highest fermentative activity and the highest alcohol-durability by the dipping method in 20% alcohol for 48 hr, at 20°C, that was similar to moromi (main mash) yeasts in Japanese sake brewing; the cells grown in the stationary culture (with cotton plug) supplemented with PL showed the lowest fermentative activity and relatively low alcohol-durability, similar to moto (seed mash) yeasts; the cells grown anaerobically in PL-unsupplemented media showed high fermentative activity but the lowest alcohol-durability.     

细胞分裂素氧化酶/脱氢酶的生理生化和分子特性

文章对细胞分裂素氧化酶/脱氢酶(CKX)的结构、生理生化特性、基因功能及表达调控等方面的研究进展作了介绍.     

Origins and Properties of Dental,Thymic, and Bone Marrow Mesenchymal Cells and Their Stem Cells

Mesenchymal cells arise from the neural crest (NC) or mesoderm. However, it is difficult to distinguish NC-derived cells from mesoderm-derived cells. Using double-transgenic mouse systems encoding P0-Cre, Wnt1-Cre, Mesp1-Cre, and Rosa26EYFP, which enabled us to trace NC-derived or mesoderm-derived cells as YFP-expressing cells, we demonstrated for the first time that both NC-derived (P0- or Wnt1-labeled) and mesoderm-derived (Mesp1-labeled) cells contribute to the development of dental, thymic, and bone marrow (BM) mesenchyme from the fetal stage to the adult stage. Irrespective of the tissues involved, NC-derived and mesoderm-derived cells contributed mainly to perivascular cells and endothelial cells, respectively. Dental and thymic mesenchyme were composed of either NC-derived or mesoderm-derived cells, whereas half of the BM mesenchyme was composed of cells that were not derived from the NC or mesoderm. However, a colony-forming unit-fibroblast (CFU-F) assay indicated that CFU-Fs in the dental pulp, thymus, and BM were composed of NC-derived and mesoderm-derived cells. Secondary CFU-F assays were used to estimate the self-renewal potential, which showed that CFU-Fs in the teeth, thymus, and BM were entirely NC-derived cells, entirely mesoderm-derived cells, and mostly NC-derived cells, respectively. Colony formation was inhibited drastically by the addition of anti-platelet–derived growth factor receptor-β antibody, regardless of the tissue and its origin. Furthermore, dental mesenchyme expressed genes encoding critical hematopoietic factors, such as interleukin-7, stem cell factor, and cysteine-X-cysteine (CXC) chemokine ligand 12, which supports the differentiation of B lymphocytes and osteoclasts. Therefore, the mesenchymal stem cells found in these tissues had different origins, but similar properties in each organ.     

Physical,Chemical and Physiological Properties of S-CM Subunits of Ricin D

Some physical, chemical and physiological properties of two S-CM subunits (S-CM Ile and S-CM Ala chain) of ricin D were studied. Physical properties of subunits are summerized in Table I. The S-CM subunits consisted of 244 (S-CM Ile chain) and 254 (S-CM Ala chain) amino acid residues. By the specific cleavage of the single intermolecular disulfide bond of ricin D, no remarkable change in conformation of polypeptide chains of ricin D was detected, but the toxicity was markedly decreased. The toxicity of ricin D is due to the quaternary structure of the ricin D molecule.     

Arsenic species uptake and translocation in Elodea canadensis

Abstract

The capacity of Elodea canadensis to phytofiltrate arsenic species from water was evaluated. Plants were adapted to tap water and supplemented with 15 and 250?µg L^?1 of As. Inorganic arsenic species (As III, As V), and organic arsenic compounds: monomethylarsonate (MMA) and dimethylarsinate (DMA) were analyzed. Sampling was carried out at different times after exposure in culture water and plant organs. Plants exposed to 15?µg L^?1 of As concentration showed no significant difference on As concentration (95% confidence level) in their organs compared to controls. When plants were exposed to 250?µg L^?1 of As concentration, a significant increase of As concentration in plant organs was observed. After 1?h exposure, plants reduce 63.16% the As concentration in the culture water, with a bioaccumulation factor (BF) of 4.3. Under these conditions, E. canadensis accumulate As V in roots and do not translocate it to stems (transfer factor <1). MMA was determined in stems and leaves. E. canadensis effectively phytofiltrate As from tap water of a city located in an arsenic endemic area from concentrations of 36?µg L^?1 to undetectable levels (10?ng L^?1).     

Spread of Elodea canadensis in Lake Baikal

In Lake Baikal Elodea canadensis Michx. was first observed at the end of the 1970's.Suggestions have been made as to the bringing of E. canadensis to Baikal by aquarists or by transport vehicles and transport together with fishes taken from lakes of the Urals where mass development of the plant was observed at the beginning of the present century. The spread of E. canadensis along Lake Baikal must be due to navigation, but natural factors also affect its spread.The quantitative biomass development of E. canadensis in various areas of the lake is reviewed, and discussed in relation to historical aspects of spread and regulation by environmental factors.The fast spread of E. canadensis, its high competitive quality and metabolic capacities for purifying sewage waters deserve attention.Expansion of E. canadensis may be referred to as a catastrophic phenomenon. Its effect has now covered practically the whole perimeter of Lake Baikal.     

Pharmacological Properties and Physiological Function of a P2X-Like Current in Single Proximal Tubule Cells Isolated from Frog Kidney

Although previous studies have provided evidence for the expression of P2X receptors in renal proximal tubule, only one cell line study has provided functional evidence. The current study investigated the pharmacological properties and physiological role of native P2X-like currents in single frog proximal tubule cells using the whole-cell patch-clamp technique. Extracellular ATP activated a cation conductance (P2X(f)) that was also Ca2+-permeable. The agonist sequence for activation was ATP = αβ-MeATP > BzATP = 2-MeSATP, and P2X(f) was inhibited by suramin, PPADS and TNP-ATP. Activation of P2X(f) attenuated the rundown of a quinidine-sensitive K+ conductance, suggesting that P2X(f) plays a role in K+ channel regulation. In addition, ATP/ADP apyrase and inhibitors of P2X(f) inhibited regulatory volume decrease (RVD). These data are consistent with the presence of a P2X receptor that plays a role in the regulation of cell volume and K+ channels in frog renal proximal tubule cells.     

The uptake,translocation and release of phosphorus by Elodea densa

Short-term (16 h) laboratory studies of ³²P uptake by Elodea densa rooted in sediment demonstrated both foliar and root uptake, and that translocation occurred acropetally and basipetally. Root absorption is projected to provide 83–85% of total phosphorus uptake during 12–16 h photoperiod days. Measured foliar uptake and excretion rates suggest that there would be no net leakage of phosphorus into the water by undamaged actively-growing E. densa. Foliar uptake decreased and root uptake increased in the dark relative to rates under light.     

Physiological and Biochemical Changes in Bacterial Cells Exposed to Oxygen

Pure oxygen at 1 atm exerts two opposite effects on Pseudomonas saccharophila: it inhibits sucrose uptake and lipid synthesis, but it enhances the formation of polysaccharides.     

Spread of Elodea canadensis in Lake Baikal

Elodea canadensis Michx. was first observed in Lake Baikal at the end of the 70's. E. canadensis was probably introduced to Baikal by aquarists or by transport vehicles and transport together with fishes taken from lakes of the Urals, where mass development of the plant was observed at the beginning of the present century. The spread of E. canadensis along lake Baikal may be due to navigation, but natural factors also affect its spread.The fast spread of E. canadensis, its high competitive quality and metabolic properties for purifying sewage waters are of interest.The expansion of E. canadensis may be considered a catastrophic phenomenon; its effect now covers practically the whole perimeter of Lake Baikal.     

STUDIES ON SEEDS : III. Isolation and Structure of Lipid-Containing Vesicles

Two structurally distinct lipid vesicles are present in pea and bean cotyledons during the first few days of germination. Both were isolated by sucrose density gradient centrifugation without significant morphological changes. Lipid vesicles of one type were elongated into a sausage-like or flattened-saccular shape, and were interassociated into sheets which were usually one vesicle thick. These sheets remained intact during homogenization and centrifugation, because some of the lipid vesicles in the sheet were interconnected through their bounding membranes, and because there seemed to be a bonding substance between adjacent vesicles. These vesicles were called "composite" lipid vesicles to distinguish them from the more usual, or "simple," lipid vesicles of other plant and animal tissues. Lipid vesicles of the other type were usually larger than the composite lipid vesicles and were always spherical in form. These vesicles remained single and did not interassociate into sheets. They were probably equivalent to the simple lipid vesicles of other tissues.     

Investigation of the Physiological,Biochemical and Antifungal Susceptibility Properties of Candida auris

Background

Candida auris is an emerging pathogen associated with outbreaks in clinical settings. Isolates of the pathogen have been geographically clustered into four clades with high intra-clade clonality. Pathogenicity varies among the clades, highlighting the importance of understanding these differences.

Objectives

To examine the physiological and biochemical properties of each clade of C. auris to improve our understanding of the fungus.

Methods

Optimal growth temperatures of four strains from three clades, East Asia, South Asia and South Africa, were explored. Moreover, assimilation and antifungal susceptibility properties of 22 C. auris strains from the three clades were studied.

Results

The optimal growth temperatures of all strains were 35–37 °C. Assimilation testing demonstrated that the commercial API ID 32 C system can be used to reliably identify C. auris based on the biochemical properties of the yeast. Notably, C. auris can be uniquely differentiated from commonly clinical fungi by its ability to assimilate raffinose and inability to utilize D-xylose, suggesting a useful simple screening tool. The antifungal susceptibility results revealed that all strains are resistant against fluconazole (minimal inhibitory concentration (MIC) 4 to?>?64 µg/mL) and miconazole (MIC 8 to?>?16 µg/mL), with strains from the Japanese lineage showing relatively lower MIC values (1–4 µg/mL). Conversely, itraconazole, voriconazole, amphotericin B, micafungin and caspofungin were active against most of the tested strains. On the clade level, East Asian strains generally showed lower MICs against azoles comparing to the other clades, while they displayed MICs against flucytosine higher than those of strains from South Africa and South Asia clades.

Conclusion

Our data suggest a simple identification approach of C. auris based on its physiological and biochemical properties and highlight aspects of C. auris population from various clades.

     

Chemical Properties and Physiological Actions of Crustacean Chromatophorotropins

The crustacean pigment-translocating hormones, the red pigment-concentratinghormone (RPCH), an octapeptide, and the light-adapting distalretinal pigment hormone (DRPH), an octadecapeptide, are thefirst invertebrate neurohormones to be fully characterized.Studies with both purified and synthetic hormones show that,in certain decapods, RPCH is a general pigment-concentratinghormone (PCH), affecting the pigments of all kinds of chromatophores(erythrophores, xanthophores, leucophores and melanophores);the DRPH seems to serve not only light-adapting function, butalso act as a general chromatophore pigment-dispersing hormone(PDH). The two hormones thus function as antagonists when regulatingthe color-adaptation of the decapod crustaceans. PCH activityis widely distributed within the arthropod endocrine systems.The first characterized insect neurohormones, the locust adipokinetichormones (AKH I and AKH II), show close structural similaritiesto the crustacean hormone, indicating a common evolution ofsome of the arthropod neurohormones. Physiological studies ofthe three hormones (RPCH, AKH I, and AKH II) and their syntheticanalogs show that they crossreact, i.e., they all exhibit pigment-concentratingactivity when tested on decapod crustaceans, adipokinetic activitywhen tested on locusts, and hyperglycemic activity when testedon cockroaches, although each of the hormones is more potentin its own system. Structure-function studies show, however,that quite different binding-site requirements exist for thehormones in activating their receptors on the various targettissues. The physiological specificity in their action thereforeseems to depend on a differential evolution of the hormone receptors.