Severely damaged kidneys possess multipotent renoprotective stem cells

Background aimsTissue-specific stem cells are a promising target for kidney regeneration, because it has been shown that they play a primary role in kidney repair. Several methods have been developed for the isolation of stem/progenitor cells from healthy kidneys but the existence of these cells in chronically damaged kidneys has not been noticed so far.MethodsA mouse model of chronic kidney failure was developed by ligation of the left ureter for 5 months, and then isolation of stem cells from this tissue as well as normal kidneys was attempted.ResultsWe found that multipotent stem cells could be isolated from both types of tissue. In addition, the cells isolated from damaged kidneys showed potential for homing to the site of injury and a renoprotective effect in an animal model of cisplatin-induced nephropathy.ConclusionsThese results show that multipotent renoprotective stem cells exist in severely damaged kidneys, which could be a target for designing new therapies.     

Effects of Polyhydric and Monohydric Compounds on the Stability of Type I Receptors for Adrenal Steroids in Brain Cytosol

We have shown previously that unoccupied type I receptors for adrenal steroids in brain cytosol lose their capacity to bind [3H]aldosterone ([3H]ALDO) in a time- and temperature-dependent manner. Based on reports that sugars and polyvalent alcohols are capable of stabilizing a variety of globular proteins, we attempted in the present study to stabilize type I receptors by including polyhydric compounds in our brain cytosol preparations. However, contrary to expectations, adjusting cytosol to a 10% (g/dl) concentration of ethylene glycol, glycerol, erythritol, xylitol, ribitol, or sorbitol failed to stabilize these receptors at 0 degree C and in fact produced a slight reduction in [3H]ALDO binding capacity. The magnitude of this reduction was greater when cytosol was incubated for 2 h at 22 degrees C prior to incubation with [3H]ALDO. In contrast to these results, when brain cytosol was adjusted to a 10% (g/dl) concentration of the monohydric compound, ethanol, a significant increase in [3H]ALDO binding to type I receptors was found. Under identical conditions, methanol and propanol failed to have a significant effect on the binding capacity of these receptors. When cytosol was aged for 2 h at 22 degrees C, all three of these monohydric compounds produced a marked loss in the [3H]ALDO binding capacity of type I receptors. An investigation of various doses of ethanol at 0 degree C on the subsequent binding of [3H]ALDO yielded an inverse U-shaped curve with 10% ethanol producing the highest level of specific binding, as reflected by an increase in maximal binding in Scatchard plots, and 40% ethanol producing a complete loss in type I receptor binding capacity.(ABSTRACT TRUNCATED AT 250 WORDS)     

Partial purification and characterization of a novel Mg2+-dependent ATPase present in the cytosol from human erythrocytes

Mg2+-ATPase activity was identified in the cytosol of human erythrocytes. A partial purification of this activity was achieved by an initial DEAE-Sephadex column chromatography, followed by gel filtration on Sephadex G-100 and then a second DEAE-Sephadex chromatography procedure. The enzyme appeared in the void volume of the Sephadex G-100 column and was retained on an Amicon XM100A ultrafiltration membrane. The molecular weight of the enzyme was estimated to be 113 000 from SD gels. The above purification protocol yielded an enzyme with an optimal pH between 7.6 and 8.2. The enzyme activity increased linearly between 30 and 44 degrees C. It was stable for several months at -20 degrees C. Magnesium was essential for activity, but the rate attainable with Mn2+ was at least as great as that due to Mg2+. No other divalent cation was able to substitute for Mg2+ or Mn2+. Neither low nor high Ca2+ concentrations significantly affected the enzymatic activity. Substrate specificity studies showed that ATP was the preferred substrate followed by CTP (46% of the rate produced by ATP). Hydrolysis of GTP, UTP, ITP and ADP was less than 10% of the rate seen with ATP. No phosphatase, pyrophosphatase, phosphodiesterase, hexokinase, phosphofructokinase or adenylate cyclase activity could be detected in this enzyme preparation. Calmodulin, which stimulates the (Ca2+ + Mg2+)-ATPase of the human erythrocyte membrane, failed to enhance the Mg2+-ATPase activity. Of considerable interest, the activity of this Mg2+-ATPase was enhanced approximately 5-fold by low concentrations of mercuric ion, p-hydroxymercuribenzoate and DTNB, but was much less sensitive to iodoacetamide.     

The relationship between sociodemographic variables and pregnancy loss in a rural area of Bangladesh

This study examines the relationship between eight sociodemographic variables and the risk of pregnancy loss in a rural area of Bangladesh. The risks of spontaneous miscarriage and stillbirth were significantly associated with maternal age, pregnancy order and previous pregnancy wastage.     

Two-spotted spider mite reared on resistant eggplant affects consumption rate and life table parameters of its predator,Typhlodromus bagdasarjani (Acari: Phytoseiidae)

The blue tick, Rhipicephalus microplus, threatens cattle production in most tropical and subtropical areas of the world. Delayed skin hypersensitivity reactions are thought to cause Nguni cattle to be more resistant to R. microplus than Bonsmara cattle yet the cellular mechanisms responsible for these differences have not been classified. Tick counts and inflammatory cell infiltrates in skin biopsies from feeding sites of adult R. microplus ticks were determined in 9-month-old Nguni and Bonsmara heifers to determine the cellular mechanisms responsible for tick immunity. Nguni heifers (1.7 ± 0.03) had lower (P < 0.05) tick counts than the Bonsmaras (2.0 ± 0.03). Parasitized sites in Nguni heifers had higher counts of basophils, mast and mononuclear cells than those in the Bonsmara heifers. Conversely, parasitized sites in Nguni heifers had lower neutrophil and eosinophil counts than those in the Bonsmara heifers. Tick count was negatively correlated with basophil and mast cell counts and positively correlated with eosinophil counts in both breeds. In the Bonsmara breed, tick count was positively correlated with mononuclear cell counts. Cellular responses to adult R. microplus infestations were different and correlated with differences in tick resistance in Nguni and Bonsmara cattle breeds. It is essential to further characterise the molecular composition of the inflammatory infiltrate elicited by adult R. microplus infestation to fully comprehend immunity to ticks in cattle.     

Characterization of the iron-containing superoxide dismutase and its response to stress in cyanobacterium Spirulina (Arthrospira) platensis

Superoxide dismutase (SOD) is considered a primary antioxidant which defends against reactive oxygen species that are induced by environmental stress. In this study, we examined changes in SOD activity and expression in the cyanobacterium Spirulina (Arthrospira) platensis under iron and salinity stress; we characterized its induction under these stress conditions and we overexpressed the enzyme in a bacterial host for preliminary characterization. Analysis of SOD isoforms concludes that S. platensis was found to regulate only the iron-containing SOD isoform (FeSOD) in response to two types of stress that were tested. The FeSOD expression (on the level of both mRNA and enzyme activity) was induced by the stress conditions of salinity and iron levels. The FeSOD from S. platensis was overexpressed in Escherichia coli BL21. The recombinant FeSOD protein (about 23 kDa) was purified for characterization. It showed high specific activity and pH stability at 6.0–9.0, and it is relatively thermostable, retaining 45 % of its activity after 30 min at 90 °C. Phylogenetic analysis reveals that S. platensis FeSOD is grouped with the FeSODs from other cyanobacterial species and separated from those of the eukaryotic Chlorophyta, suggesting that the FeSOD gene may be used as a molecular marker in physiological, phylogenetic, and taxonomic studies. This study also suggests that the increased activity and expression of SOD may play a role in algal survival under stress conditions.     

Evidence of Alternaria alternata Causing Leaf Spot of Aloe vera in Iran

A leaf spot and leaf blight disease was observed on Aloe vera plants as small, circular to oval dark brown necrotic sunken spots on leaves. Infected tissues collected from different sites in diseased fields were cultured on potato carrot agar medium, and the pathogen was identified as Alternaria alternata on the basis of morphological and cultural characteristics. The conidiophores were branched, straight, golden brown, smooth‐walled, measuring up to μm long by 3 μm wide with one conidial scar. The conidia were golden brown in colour and produced in long branched chains, obclavate in shape and in short conical flask. Pathogenicity tests conducted on healthy potted aloe plants in a glasshouse showed typical leaf spot symptoms after 4–7 days. The optimal temperature for the growth of A. alternata was 25°C.