The induction of Guerin’s carcinoma cytochrome P450 hydroxylase activity by retinoids

Using Guerin’s carcinoma as a model the interrelationship between the tumor growth process and supplementation of the body with vitamin A has been studied. The replenishment of vitamin A resources of vitamin-deficient tumor bearing animals modulated the Guerin’s carcinoma growth rate in a dose dependent manner (r = 0.83). The morphological parameters of tumor growth under conditions of supplementation with vitamin A (0–3000 IU) positively correlated with hydroxylase (r = 0.81) and demethylase (r = 0.49) activities of the Guerin’s carcinoma cytochrome P450 system. The increase in the tumor growth rate together with the induction of hydroxylase and demethylase activities of cytochrome P450 in the Guerin’s carcinoma microsomal fraction, observed either under conditions of retinyl acetate overdose supplementation, or selective liposomal form of all-trans-retinoic acid, suggests the stimulatory effect of retinoids on tumor growth.     

Copeptin is associated with mortality and outcome in patients with acute intracerebral hemorrhage

Background  

Spontaneous intracerebral hemorrhage (ICH) accounts for a high mortality and morbidity. Early prediction of outcome is crucial for optimized care and treatment decision. Copeptin, the C-terminal part of provasopressin, has emerged as a new prognostic marker in a variety of diseases, but its prognostic value in ICH is unknown.     

Low pH Modulates the Macroorganization and Thermal Stability of PSII Supercomplexes in Grana Membranes

Protonation of the lumen-exposed residues of some photosynthetic complexes in the grana membranes occurs under conditions of high light intensity and triggers a major photoprotection mechanism known as energy dependent nonphotochemical quenching. We have studied the role of protonation in the structural reorganization and thermal stability of isolated grana membranes. The macroorganization of granal membrane fragments in protonated and partly deprotonated state has been mapped by means of atomic force microscopy. The protonation of the photosynthetic complexes has been found to induce large-scale structural remodeling of grana membranes—formation of extensive domains of the major light-harvesting complex of photosystem II and clustering of trimmed photosystem II supercomplexes, thinning of the membrane, and reduction of its size. These events are accompanied by pronounced thermal destabilization of the photosynthetic complexes, as evidenced by circular dichroism spectroscopy and differential scanning calorimetry. Our data reveal a detailed nanoscopic picture of the initial steps of nonphotochemical quenching.     

A new efficient expression system for Bacillus and its application to production of recombinant phytase

A new expression system was developed for Bacillus subtilis.This system uses a shuttle vector (B. subtilis– Eschericia coli) carrying a phosphate starvation-inducible promoter (pst) and on a fed-batch cultivation strategy. The pst-promoter proved to be very strong and retain its tight regulation also when present on a multi-copy plasmid. The expression system developed showed promising results when applied to the production of recombinant Bacillusphytase – phytase activity at the end of cultivation reached 28.7 U ml^–1.     

The induction of bacterial bioluminescence system on solid medium

Induction of the luminescence system of the marine luminous bacteriumVibrio harveyi growing on a solid medium was studied. The induction occurred when the total number of cells per square centimeter of solid medium approached 10⁴ cells (i.e., either 100 colonies consisting of 100 cells per each colony or 1 colony with about 10⁴ cells). The preinduction period and number of cells per colony at the time of induction decreased as the number of colonies per cm² increased. The ecological significance of the induction of the luminescence system on solid medium is discussed.     

Removal of Humic Substances from Aqueous Solution by Fungal Pellets

The removal of humic substances from aqueous solution at pH=4.8 and 6.0 and 25 °C by pure culture of Aspergillus niger has been examined. The removal of humic substances from aqueous phase was monitored by following the decrease in absorbance at 370 nm. COD and fungal growth were also measured. The initial concentration of humic and fulvic acids, pH and diameter of fungal pellets were found to be the most important parameters. The results suggested that decolorization of batch culture was a consequence of several processes. In the first 5 hours for pellets with diameter 1-3 mm and 10 hours for pellets with diameter 2-5 mm adsorption of humic substances was dominant. Afterwards, desorption of slightly bound humic substances and their degradation, as well as degradation of remaining humic substances in the solution, continued simultaneously through the period of 10 days.     

Distribution and flower visitation records of bumblebees in Lebanon (Hymenoptera: Apidae)

Summary

West Palearctic bumblebees are common wildflowers and crop pollinators that are well studied in their central and northern distribution ranges, but fewer information is available on their southern distribution areas. Lebanon falls on the southern limit of their distribution and no published information is available on the local bumblebees. Our study aims to produce a data baseline of the local bumblebee species. In order to do so we grouped available old records of bumblebees in Lebanon with recent author collections and produced preliminary distribution maps. We listed four species: Bombus terrestris, B. argillaceus, B. niveatus vorticosus and B. melanurus. Preliminary distribution shows that Bombus terrestris and B. argillaceus are widespread and have a large foraging range, whereas B. niveatus vorticosus and B. melanurus have a restricted distribution to altitudes above 1800 m with a smaller foraging range. The male cephalic labial gland secretions analysis of local Bombus terrestris specimens provides preliminary evidence that the local subspecies could be Bombus terrestris calabricus. Therefore, we highlight the importance of regulating foreign Bombus terrestris subspecies importation for agriculture purposes, as well as monitoring B. niveatus vorticosus and B. melanurus that are rendered vulnerable by their isolated populations.