Purification of a new cytochrome P-450 from human liver microsomes

Using a classical methodlogy of purification consisting of three chromatographic steps (Octyl-Sepharose, DEAE-cellulose, CM-cellulos) we have purified a new cytochrome P-450 from human liver microsomes. It was called cytochrome P-450₉. It has been proven to be different from all preceedingly purified human liver microsomal cytochrome P-450 isozymes by its immunological and electrophoretical properties. It does not cross-react with any rat liver cytochrome P-450 and anti-cytochrome P-450₉, does not recognize rat liver microsomes; thus this cytochrome P-450₉ is specific to humans. This cytochrome P-450 isozyme exists in low amounts in human liver microsomes and exhibits an important quatitative polymorphism. In reconstituted system, cytochrome P-450₉ is able to hydroxylate all substrates tested but is not specific on any; its exatc role in xenobiotic metabolism in man remains to be elucidated.     

Population biology of an endangered species: the common guitarfish Rhinobatos rhinobatos in Lebanese marine waters of the eastern Mediterranean Sea

This study focuses on the population biology of the common guitarfish Rhinobatos rhinobatos, a cartilaginous fish listed as Endangered in the International Union for the Conservation of Nature (IUCN) Red List. Between December 2012 and January 2014, 67 individuals were collected by bottom longlining in coastal Lebanese marine waters at different ports at depths ranging from 10 to 110 m. The total length (L_T) of the specimens ranged from 50 to 143 cm, and the mean ± s.d . was 76·2 ± 19·7 cm. The most common L_T classes were between 60 and 70 cm. The total mass of the specimens ranged from 410 to 10 000 g, and the mean ± s.d . was 1841 ± 1987 g. A total of 34 males and 33 females were collected, and the sex ratio was not significantly different from 1:1. The mass and L_T relationship showed positive allometric growth (b = 3·096 and r² = 0·99), and the mean ± s.d . L_T at which 50% of the individuals were sexually mature was 84·73 ± 5·81 cm for females and 78·57 ± 4·88 cm for males. The gonado‐somatic and hepato‐somatic indices were determined along with a condition factor, and parturition appeared to occur in winter. The primary prey items found in the fish stomachs during the autumn and winter seasons were Penaeidae. The results of this study will help to parameterize models of the population dynamics for this exploited fish stock to ensure the long‐term sustainability of its fishery.     

Morphological changes in the middle intestine of the rainbow trout,Salmo gairdneri,induced by a hyperosmotic environment

Summary The structural modifications in the middle intestine of the trout, Salmo gairdneri, induced by transfer to seawater have been studied. During the first two days in seawater, significant distensions of the intercellular spaces are observed between the apical tight junctions and the basement membrane. These dilations are more frequent in the apical part of the intestinal folds. At the basal part of the cell, numerous lamellar processes open in the intercellular spaces. They are closely associated with elongated mitochondria, and are often mixed with small clear vesicles. After seven days in seawater, intercellular spaces are less expanded. Numerous mitochondria are observed in the apical part of the cell, and numerous myelinic bodies with dense granules lie near the nucleus. After one month in seawater, the epithelium resembles that of the freshwater controls; mitochondria are more numerous and other organelles are well developed. The most important modifications of the ultrastructure of the intestine mucosa occur during the first two days in seawater, in correlation with important physiological changes following the abrupt increase of environmental salinity.     

Localization of melanotropin-like peptides in the central nervous system of two insect species,the migratory locust,Locusta migratoria,and the fleshfly,Sarcophaga bullata

Summary By use of well characterized antisera in the peroxidase-antiperoxidase method, we were able to demonstrateMSH andMSH immunoreactive cells and nerve fibres within the nervous system of adults and larvae ofLocusta migratoria and 3-, 5- and 8-day-old adultSarcophaga bullata. In neither of these insect species, any immunoreaction was obtained with a ₃MSH-antiserum. Double immuno-histochemical stainings revealed thatMSH-like andMSH-like substances are located in different cells. These cells show no immunoreactivity to a number of antisera against other POMC-derivatives (anti-lipotropin, anti-endorphin, anti-ACTH_1–24); thus they appear to containMSH- orMSH-like material in a specific way. The function of the immunologically detected peptides remains to be demonstrated. The distribution of the immunoreactive material suggests that, like in amphibians and other lower vertebrates, the synthesis or release of melanotropins might be under the influence of external stimuli. The present observations support the recently developed concept that even some of the smallest neuropeptides, the melanotropins, have been highly conserved during a long period of evolution.     

<Emphasis Type="Italic">Candida dubliniensis</Emphasis>: Epidemiology and Phenotypic Methods for Identification

Candida dubliniensis is an emerging pathogen first described in 1995, which shares many phenotypic features with Candida albicans and therefore may be misidentified in microbial laboratories. Despite various phenotypic techniques described in the literature to differentiate the two species, the correct identification of C. dubliniensis remains problematic due to phenotypic similarities between these species. Thus, as the differences between both are best characterized at genetic levels, several molecular methods have been proposed to provide a specific and rapid identification of this species. Epidemiological studies have shown that C. dubliniensis is prevalent throughout the world and it is primarily associated with oral carriage and oropharyngeal infections in patients infected with human immunodeficiency virus (HIV). However, data acquired from its isolation from other healthy and immunocompromised patients are variable, and there is still no real consensus on the epidemiological relevance of this species. In this article, we review the various phenotypic methods used in the identification of C. dubliniensis and the epidemiological impact of this new species.     

PRP4K is a HER2-regulated modifier of taxane sensitivity

The taxanes are used alone or in combination with anthracyclines or platinum drugs to treat breast and ovarian cancer, respectively. Taxanes target microtubules in cancer cells and modifiers of taxane sensitivity have been identified in vitro, including drug efflux and mitotic checkpoint proteins. Human epidermal growth factor receptor 2 (HER2/ERBB2) gene amplification is associated with benefit from taxane therapy in breast cancer yet high HER2 expression also correlates with poor survival in both breast and ovarian cancer. The pre-mRNA splicing factor 4 kinase PRP4K (PRPF4B), which we identified as a component of the U5 snRNP also plays a role in regulating the spindle assembly checkpoint (SAC) in response to microtubule-targeting drugs. In this study, we found a positive correlation between PRP4K expression and HER2 status in breast and ovarian cancer patient tumors, which we determined was a direct result of PRP4K regulation by HER2 signaling. Knock-down of PRP4K expression reduced the sensitivity of breast and ovarian cancer cell lines to taxanes, and low PRP4K levels correlated with in vitro-derived and patient acquired taxane resistance in breast and ovarian cancer. Patients with high-grade serous ovarian cancer and high HER2 levels had poor overall survival; however, better survival in the low HER2 patient subgroup treated with platinum/taxane-based therapy correlated positively with PRP4K expression (HR = 0.37 [95% CI 0.15-0.88]; p = 0.03). Thus, PRP4K functions as a HER2-regulated modifier of taxane sensitivity that may have prognostic value as a marker of better overall survival in taxane-treated ovarian cancer patients.     

In search for non-steroidogenic functions of the prothoracic glands of the desert locust, Schistocerca gregaria: a peptidomic and proteomic approach

The only well established function of the prothoracic glands (PGs) of insects is the production of ecdysteroids. In gregarious locusts, like in most insect species, the PGs degenerate soon after the adult molt. In this way they resemble the thymus of mammals, a gland with an important role in the build up of the immune system in young animals. In adult solitarious locusts the PGs persist much longer, however without producing substantial amounts of ecdysteroids. In the literature the existence of a well developed rough endoplasmic reticulum and Golgi complex system has been repeatedly reported, suggesting an active role in peptide or/and protein synthesis and release. The nature of the secreted products remained unknown. Our pepdidomic analysis of an acidified methanolic extract of PGs of last instar gregarious nymphs did not yield any indication for the presence of known locust or other peptides. The peptide release assay was also negative. For our proteomic analysis, we developed an EST-based identification strategy. We successfully identified 50 protein spots on a two dimensional map. In addition to typical protein synthesis-related proteins, a number of proteins with a role in detoxification processes were found, suggesting some role of the PGs in the defense system.