Mitochondrial ABC transporter Atm1p is required for protection against oxidative stress and vacuolar functions in Schizosaccharomyces pombe

A potential correlation between mitochondrial and vacuolar functions is known to exit in yeast. Fission yeast atm1(+), SPAC15A10.01, encodes a putative half-type ABC transporter with an N-terminal mitochondrial-targeting signal. In an attempt to evaluate the possible involvement of mitochondrion in vacuole function, a functional analysis of atm1(+) was performed by gene disruption. Growth of the atm1 mutant was inhibited in the presence of oxidizing agents, and S. cerevisiae Atm1p was found to complement this growth defect. atm1Delta cells exhibited defects in fluid-phase endocytosis and vacuolar fusion under hypotonic stress. GFP-tagged Atm1p was observed to be localized in the mitochondria. These data strongly suggest that fission yeast Atm1p was not only involved in protection against oxidative stress, but also played a role in vacuolar functions.     

Adiponectin inhibits the binding of low-density lipoprotein to biglycan, a vascular proteoglycan

The aim of this study was to test the possibility that adiponectin has an antiatherogenic effect through the inhibition of LDL binding to proteoglycans, an initial event in atherogenesis. Both full-length and globular adiponectin inhibited LDL binding in a dose-dependent manner. Both types of adiponectin bound to biglycan in a dose-dependent manner. Immunoprecipitation and immunoblotting analysis showed interaction of full-length adiponectin with LDL. Pretreatment of biglycan with globular adiponectin prior to LDL addition diminished the inhibitory effect, while pretreatment with full-length adiponectin retained the effect. This is a new antiatherogenic property that appears independent of the receptor-mediated hormonal action of adiponectin.     

The effects of lysosomal and proteasomal inhibitors on abnormal forms of prion protein degradation in murine macrophages

It has been reported that macrophages degrade infectious forms of prion protein (PrP(Sc) ). In order to investigate the mechanisms underlying PrP(Sc) degradation in macrophages, the effects of lysosomal and proteasomal inhibitors on macrophage cell lines which were incubated with scrapie-affected brain homogenate were studied. PrP(Sc) degradation was inhibited in the presence of both proteasomal and lysosomal inhibitors. Indirect fluorescence assays to determine the cellular localization of PrP(Sc) were undertaken. PrP(Sc) colocalized with the lysosomal membrane protein Lamp-1 and ubiquitin, a protein that is related to the proteasome. The present data indicate that macrophages might degrade PrP(Sc) via the lysosomal and proteasomal pathways.     

Prevalence of periodontopathic bacteria on the tongue dorsum of elderly people

Objectives: The aim of this study was to analyse the prevalence of oral bacteria on the dorsum of the tongue. In addition, the relationship between the number of teeth and the microflora present on the coating of the tongue in a population of 85‐year‐old people was assessed. Subjects and methods: Two hundred and five individuals (89 males, 116 females) from the same geographical area who were 85 years of age were examined. Five periodontopathic bacteria (Porphyromonas gingivalis, Tannerella forsythia, Actinobacillus actinomycetemcomitans, Fusobacterium nucleatum, and Treponema denticola) and one cariogenic bacterium (Streptococcus mutans) were analysed using a polymerase chain reaction assay of tongue samples from the population. Results: Periodontal bacteria‐positive individuals have more teeth than that of periodontal bacteria‐negative people. Between the periodontal bacteria‐positive and ‐negative individuals, there were significant differences in the mean number of teeth for P. gingivalis (p < 0.0001), T. denticola (p < 0.001), F. nucleatum (p = 0.002), and T. forsythia (p = 0.005), while there were no significant differences for A. actinomycetemcomitans (p = 0.998) or S. mutans (p = 0.147). Conclusions: A wide range of species, including anaerobes, was detected in 85‐year‐old subjects. It was found that the detection of periodontal bacteria on the tongue coating increased with the number of teeth. There was a positive relationship between the tooth number and periodontopathic bacteria, except for A. actinomycetemcomitans.These results suggest that tongue care is essential for preventing oral disease and needs to be part of any oral care programme in elderly people.     

Sexual variations in food quality and gastrointestinal features of sika deer (Cervus nippon) in Japan during winter: implications for feeding strategy

We assessed sexual variation in food quality and gut macrostructure in adult male and pregnant female sika deer, Cervus nippon (Temminck, 1838), in Japan during winter. These variations might have important implications relative to sexual differences in habitat use, forage acquisition, and digestive strategy. According to the sexual dimorphism-body size hypothesis the larger males would feed on poorer forage and have heavier stomach contents and heavier intestine contents and longer intestines than smaller females. However, the food quality in rumen contents of males was higher than, or at least similar with, that of pregnant females. In correspondence to food quality, the relative weights of stomach contents and intestines with contents, the relative lengths of intestines to the lengths of body and total intestines in pregnant females were similar to adult males. The relative weights of omasum and abomasum tissues in pregnant females were greater than in males. Our findings suggest sexual differences in feeding strategy in sika deer in Japan during winter. To meet greater nutritional demands of high metabolic rate and gestation, pregnant females seemed to maintain a greater volume of digesta in guts and had more stomach tissues than expected by the sexual dimorphism-body size hypothesis to compensate for poorer forage quality.     

The functional role of arginine 901 at the C-terminus of the human anion transporter band 3 protein

To determine which arginine residues are responsible for band 3-mediated anion transport, we analyzed hydroxyphenylglyoxal (HPG)-modified band 3 protein in native erythrocyte membranes. HPG-modification leads to inhibition of the transport of phosphoenolpyruvate, a substrate for band 3-mediated transport. We analyzed the HPG-modified membranes by reverse phase-HPLC, and determined that arginine 901 was modified by HPG. To determine the role of Arg 901 in the conformational change induced by anion exchange, we analyzed HPG-modification of the membranes when 4,4'-dinitrostilbene-2,2'-disulfonic acid (DNDS) or diethypyrocarbonate (DEPC) was present. DNDS and DEPC fix band 3 in the outward and inward conformations, respectively. HPG-modification was unaffected in the presence of DEPC but decreased in the presence of DNDS. In addition to that, 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS), which specifically reacts with the outward conformation of band 3, did not react with HPG-modified membranes. Furthermore, we expressed a band 3 mutant in which Arg 901 was replaced by alanine (R901A) on yeast membranes. The kinetic parameters indicated that the R901A mutation affected the rate of conformational change of the band 3 protein. From these results, we conclude that the most C-terminal arginine, Arg 901, has a functional role in the conformational change that is necessary for anion transport.     

Toxicoproteomic analysis of a mouse model of nonsteroidal anti-inflammatory drug-induced gastric ulcers

Nonsteroidal anti-inflammatory drugs (NSAIDs) are valuable agents; however, their use has been limited by their association with mucosal damage in the upper gastrointestinal tract. NSAIDs inhibit cyclooxygenase and consequently block the synthesis of prostaglandins, which have cytoprotective effects in gastric mucosa; these effects on prostaglandins have been thought to be major cause of NSAID-induced ulceration. However, studies indicate that additional NSAID-related mechanisms are involved in formation of gastric lesions. Here, we used a toxicoproteomic approach to understand cellular processes that are affected by NSAIDs in mouse stomach tissue during ulcer formation. We used fluorogenic derivatization-liquid chromatography-tandem mass spectrometry (FD-LC-MS/MS)-which consists of fluorogenic derivatization, separation and fluorescence detection by LC, and identification by LC-tandem mass spectrometry-in this proteomic analysis of pyrolic stomach from control and diclofenac (Dic)-treated mice. FD-LC-MS/MS results were highly sensitive; 10 differentially expressed proteins were identified, and all 10 were more highly expressed in Dic-treated mice than in control mice. Specifically, expression levels of 78 kDa glucose-regulated protein (GRP78), heat shock protein beta-1 (HSP27), and gastrin were more than 3-fold higher in Dic-treated mice than in control mice. This study represents a first step to ascertain the precise actors of early NSAID-induced ulceration.     

N-glycans are not required for the efficient degradation of the mutant Saccharomyces cerevisiae CPY* in Schizosaccharomyces pombe

In eukaryotic cells, aberrant proteins generated in the endoplasmic reticulum (ER) are degraded by the ER-associated degradation (ERAD) pathway. Here, we report on the ERAD pathway of the fission yeast Schizosaccharomyces pombe. We constructed and expressed Saccharomyces cerevisiae wild-type CPY (ScCPY) and CPY-G255R mutant (ScCPY*) in S. pombe. While ScCPY was glycosylated and efficiently transported to the vacuoles in S. pombe, ScCPY* was retained in the ER and was not processed to the matured form in these cells. Cycloheximide chase experiments revealed that ScCPY* was rapidly degraded in S. pombe, and its degradation depended on Hrd1p and Ubc7p homologs. We also found that Mnl1p and Yos9p, proteins that are essential for ERAD in S. cerevisiae, were not required for ScCPY* degradation in S. pombe. Moreover, the null-glycosylation mutant of ScCPY, CPY*0000, was rapidly degraded by the ERAD pathway. These results suggested that N-linked oligosaccharides are not important for the recognition of luminal proteins for ERAD in S. pombe cells.