A Ca2+/CaM-dependent kinase from pea is stress regulated and in vitro phosphorylates a protein that binds to AtCaM5 promoter.

An immuno-homologue of maize Ca2+/calmodulin (CaM)-dependent protein kinase with a molecular mass of 72 kDa was identified in pea. The pea kinase (PsCCaMK) was upregulated in roots in response to low temperature and increased salinity. Exogenous Ca2+ application increased the kinase level and the response was faster than that obtained following stress application. Low temperature-mediated, but not salinity-mediated stress kinase increase was inhibited by the application of EGTA and W7, a CaM inhibitor. The purification of PsCCaMK using immuno-affinity chromatography resulted in coelution of the kinase with another polypeptide of molecular mass 40 kDa (p40). Western blot revealed the presence of PsCCaMK in nuclear protein extracts and was found to phosphorylate p40 in vitro. Gel mobility shift and South-Western analysis showed that p40 is a DNA-binding protein and it interacted specifically with one of the cis acting elements of the Arabidopsis CaM5 gene (AtCaM5) promoter. The binding of p40 to the specific elements in the AtCaM5 promoter was dependent of its dephosphorylated state. Our results suggest that p40 could be an upstream signal component of the stress responses.     

6-Dimethyl amino purine and 2-amino purine inhibit the induction of expresion of milk protein genes by prolactin

Two protein kinase-inhibitors, 6-dimethyl amino purine and 2-amino purine inhibited induction of -casein synthesis by prolactin when added to the culture medium of rabbit mammary explant and cells. The accumulation of the mRNA for _s1- and -caseins and for whey acidic protein did not take place in the presence of the inhibitors whereas -actin mRNA concentration was not altered. In the same experimental conditions, H7, an inhibitor of protein kinase C and, to a lower extent, of protein kinase A did not prevent prolactin from acting. These data suggest for the first time that specific protein kinases are involved in the transduction of the prolactin signal to milk protein genes.Abbreviations 6-DMAP 6-dimethyl amino purine - 2-AP 2-amino purine - H7 1-(5 isoquinoline sulfonyl)-2-methyl-piperazine dihydrochloride - WAP whey acidic protein - PRL prolactin     

Histochemical demonstration of enterokinase

Summary A new simple method for the histochemical demonstration of enterokinase (enteropeptidase, EC 3.4.4.8) was elaborated. Unfixed cold microtome sections adherent to the slides are covered with agar-gel medium containing trypsinogen (0.5–1 mg per 1 ml), N-benzoyl-DL-arginine--naphthylamide hydrochloride (2–4 mM), and Fast Blue B Salt (0.5 mg per 1 ml) in 0.05 M Tris maleate buffer pH 6.5 with 0.05% CaCl₂. After the incubation in a wet chamber at 37° C the slides are chelated in 2% copper sulphate. The method enables a localization on the histological level. The evaluation of the overall staining obtained with this method in sections of the duodenum, jejunum and ileum of guinea pigs, rats, monkeys, dogs and humans reflects well the biochemical quantitative data on enterokinase activity obtained in homogenates of mucosal scrapings of the corresponding gut segments of the same animals.In all animals a proximodistal gradient was found. The highest activities were found in enterocytes covering apical parts of villi in the duodenum. According to the activities in the duodenum the investigated animals can be arranged in the following series: guinea pig (highest activity), monkey, man, rat and dog.     

Effect of supplemental magnesium on the kidney levels of cadmium, zinc, and copper of mice exposed to toxic levels of cadmium

In this report, we present the results of our investigations on the effect of Mg pretreatment on Cd and bioelements (Cu and Zn) contents in kidney of mice exposed to acute and subacute Cd intoxication. Acute intoxication was performed on male Swiss mice given a single oral dose of 20 mg Cd/kg body weight and mice given the same dose of Cd but pretreated with 40 mg Mg/kg body weight. For subacute intoxication one group of mice was given 10 mg Cd/kg body weight every day, for 2 wk, and the other one received the same dose of Cd after oral Mg intake of 20 mg/kg body weight. Cd, Cu, and Zn content was determined in kidney by atomic absorption spectrophotometry. In acute Cd intoxication, Mg pretreatment resulted in significant decrease of Cd in kidney after 4 and 6 h, compared with animals given only Cd. Under the condition of subacute Cd intoxication, Mg supplementation reduced Cd kidney content after 2 wk for about 30%, compared with animals treated with Cd only. The effect of Mg on Cu and Zn kidney content was also beneficial.     

Development of tetracycline-serratiopeptidase-containing periodontal gel: Formulation and preliminary clinical study

The purpose of this research was to reduce the polymer concentration and to obtain reasonable viscosity at a lower concentration of pluronic by the addition of a viscosity modifier. A 20% wt/wt pluronic gel was prepared on a weight basis using the cold method. The effect of the amount of tetracycline and Aerosil on gel properties was studied. The gel was evaluated using different parameters: polarizing microscopy, gelation, gel melting, bioadhesivity, viscosity, drug release, and stability of enzyme. An in vivo study was performed to evaluate the clinical efficiency of the liquid crystalline gel. Addition of Aerosil to the gel favored hexagonal phase formation. Viscosity and bioadhesivity increased with an increase in the concentration of Aerosil. Release of tetracycline was sustained as the concentration of Aerosil increased. Various clinical parameters confirmed the acceptability and efficiency of this gel system. Published: September 15, 2006     

Mitochondrial ion channels

Ion channels are proteins, which facilitate the ions flow throught biological membranes. In recent years the structure as well as the function of the plasma membrane ion channels have been well investigated. The knowledge of intracellular ion channels however is still poor. Up till now, the calcium channel described in endoplasmatic reticulum and mitochondrial porine are the examples of intracellular ion channels, which have been well characterized. The mitochondrial potassium channels: regulated by ATP (mitoK(ATP)) and of big conductance activated by Ca2+ (mitoBK(Ca)), which were described in inner mitochondrial membrane, play a key role in the protection of heart muscle against ischemia. In this review the last date concerning the mitochondrial ion channels as well as they function in cell metabolism have been presented.