Anti-stress activity of Propionibacterium freudenreichii: identification of a reactivative protein

Propionibacterium freudenreichii subsp. shermanii is known to prevent mutations caused by various agents such as N-methyl-N'-nitro-N-nitrosoguanidine, 9-aminoacridine, 4-nitro-quinoline-1-oxide and by UV radiation in both prokaryotic and eukaryotic cells. It was also shown to prevent or repair damage caused by H(2)O(2) or UV radiation in Salmonella typhimurium and Escherichia coli, a characteristic previously designated as reactivative effect. In order to characterise this effect at the molecular level, we have purified the active component from a P. freudenreichii cell-free extract using a combination of ammonium sulfate precipitation, anion-exchange and size-exclusion chromatography. The isolated 35 kDa protein was then identified using both N-terminal and internal peptide sequencing as a cysteine synthase. The latter was localised in the P. freudenreichii proteomic map. It is constitutively expressed but also clearly induced during adaptation to detergent and heat, but not acid, stresses. The biological meaning of cysteine synthase in the context of adaptation to oxidative and non-oxidative stresses is discussed.     

Acidophilic microbial communities catalyzing sludge bioleaching monitored by fluorescent in situ hybridization

Biological autotrophic sulfur oxidation processes have been proposed to remove heavy metals from wastewater treatment sludge by bioleaching. We made a characterization of the microbial population in batch and continuous sludge bioleaching reactors using fluorescent in situ hybridization of fluorescently-labeled oligonucleotidic probes targeting rRNA in a ‚top to bottom approach’. Batch incubations of sludge with 0.2% (w/v) elemental sulfur resulted in a pH value of 5. Alpha-Proteobacteria hybridizing with probe ALF1b were dominant in this incubation. Members of the Acidophilium-group (hybridizing with probe Acdp821) of Nitrospira/Leptospirillum phylum (Ntspa712 probe) and from the archaeal domain (ARCH915) were also detected. When sludge was incubated with 1% elemental sulfur in batch or continuous reactor experiments, final pH values were always below 2. Active microbial communities consisted almost exclusively of gamma-Proteobacteria (hybridizing with probe GAM42a). However, further hybridization experiments with probe Thio820 targeting Acidithiobacillus ferroxidans and Acidithiobacillus thioxidans gave negative results. A new probe, named THIO181, encompassing all known members of the genus was designed. Hybridization perfomed with THIO181 and GAM42a showed a perfect co-localization of the hybridization signals. Further hybridization experiments with probe THIO181 and THC642, specific for the species Acidithiobacillus caldus, confirmed that this bacteria was largely responsible for the sulfur oxidation reaction in our acidophilic sludge bioleaching reactors.     

Regulation of dopamine system responsivity and its adaptive and pathological response to stress

Although, historically, the norepinephrine system has attracted the majority of attention in the study of the stress response, the dopamine system has also been consistently implicated. It has long been established that stress plays a crucial role in the pathogenesis of psychiatric disorders. However, the neurobiological mechanisms that mediate the stress response and its effect in psychiatric diseases are not well understood. The dopamine system can play distinct roles in stress and psychiatric disorders. It is hypothesized that, even though the dopamine (DA) system forms the basis for a number of psychiatric disorders, the pathology is likely to originate in the afferent structures that are inducing dysregulation of the DA system. This review explores the current knowledge of afferent modulation of the stress/DA circuitry, and presents recent data focusing on the effect of stress on the DA system and its relevance to psychiatric disorders.     

Action Spectra for Light-induced Elongation in Fern Protonemata

The action spectrum for promotion of elongation of protonemata of Onoclea sensibilis has peaks at 400–420, 580–600 and 640–660 nm. The largest growth increments at saturating light doses are produced by yellow and far-red light. Elongation induced by yellow and far-red irradiation persists in old as well as young filaments, while red-light promotion is found only in young filaments. The growth promotion caused by yellow light is partially reversed by red light down to the level of growth produced by red irradiation alone. Elongation of rhizoids is under reversible red, far-red control, while yellow light is inactive. A model is proposed and discussed in which the light-sensitive elongation of filaments is accounted for by the presence of three distinct photoreceptors: phytochrome; a pigment absorbing yellow light. P₅₈₀; and a pigment absorbing blue light, P₄₂₀.     

The Impact of ABCG2 on Bovine Mammary Epithelial Cell Proliferation

The ATP-binding cassette transporter, ABCG2, has been identified as a gene of significance in the regulation of bovine lactation by a number of gene mapping studies yet its role in lactational physiology remains unclear. We have used the potent ABCG2 specific inhibitor, Ko143, to investigate role of ABCG2 in primary bovine mammary epithelial cell (BMEC) proliferation and differentiation. After incubation with Ko143, the proliferation rate of BMECs was reduced at 48 and 72 hours by up to 80% (P?相似文献   

A general-purpose system for characterizing medically important bacteria to genus level

A computer program and accompanying data matrix have been prepared for bacteria of medical interest, to assist the assignment of an unidentified bacterium to the most likely genus. The results on a set of relatively simple tests are entered. The program prints the more likely genera, followed by a list of diagnostic tables in Cowan & Steel (1974) and Buchanan & Gibbons (1974). Where available, identification matrices for further computer-assisted study, are presented. This program may be of particular help in laboratories where a wide range of bacteria have to be identified.     

p62, Ref(2)P and ubiquitinated proteins are conserved markers of neuronal aging, aggregate formation and progressive autophagic defects

Suppression of macroautophagy, due to mutations or through processes linked to aging, results in the accumulation of cytoplasmic substrates that are normally eliminated by the pathway. This is a significant problem in long-lived cells like neurons, where pathway defects can result in the accumulation of aggregates containing ubiquitinated proteins. The p62/Ref(2)P family of proteins is involved in the autophagic clearance of cytoplasmic protein bodies or sequestosomes. These unique structures are closely associated with protein inclusions containing ubiquitin as well as key components of the autophagy pathway. In this study we show that detergent fractionation followed by western blot analysis of insoluble ubiquitinated proteins (IUP), mammalian p62 and its Drosophila homologue, Ref(2)P can be used to quantitatively assess the activity level of aggregate clearance (aggrephagy) in complex tissues. Using this technique we show that genetic or age-dependent changes that modify the long-term enhancement or suppression of aggrephagy can be identified. Moreover, using the Drosophila model system this method can be used to establish autophagy-dependent protein clearance profiles that are occurring under a wide range of physiological conditions including developmental, fasting and altered metabolic pathways. This technique can also be used to examine proteopathies that are associated with human disorders such as frontotemporal dementia, Huntington and Alzheimer disease. Our findings indicate that measuring IUP profiles together with an assessment of p62/Ref(2)P proteins can be used as a screening or diagnostic tool to characterize genetic and age-dependent factors that alter the long-term function of autophagy and the clearance of protein aggregates occurring within complex tissues and cells.