Small chromosomes among Danish Candida glabrata isolates originated through different mechanisms

We analyzed 192 strains of the pathogenic yeast Candida glabrata from patients, mainly suffering from systemic infection, at Danish hospitals during 1985–1999. Our analysis showed that these strains were closely related but exhibited large karyotype polymorphism. Nine strains contained small chromosomes, which were smaller than 0.5 Mb. Regarding the year, patient and hospital, these C. glabrata strains had independent origin and the analyzed small chromosomes were structurally not related to each other (i.e. they contained different sets of genes). We suggest that at least two mechanisms could participate in their origin: (i) through a segmental duplication which covered the centromeric region, or (ii) by a translocation event moving a larger chromosome arm to another chromosome that leaves the centromere part with the shorter arm. The first type of small chromosomes carrying duplicated genes exhibited mitotic instability, while the second type, which contained the corresponding genes in only one copy in the genome, was mitotically stable. Apparently, in patients C. glabrata chromosomes are frequently reshuffled resulting in new genetic configurations, including appearance of small chromosomes, and some of these resulting “mutant” strains can have increased fitness in a certain patient “environment”.     

Congenital toxoplasmosis: An overview of the neurological and ocular manifestations

Toxoplasma gondii is an obligate intracellular parasite which is known to infect one-third of the total world population chronically though it is asymptomatic in immunocompetent patients. However, in an immunocompromised patient or an infected fetus, it may cause devastating effects. The parasite may cross the placenta of an infected pregnant woman and probably infect the fetus congenitally. The severity of the infection depends on the gestational age at which the infection has occurred i.e., if it has occurred in the early phase, the rate of transmission is low but the severity is high if the fetus is infected and if it has occurred in the later phase then transmission rate is higher while the severity would be low. Congenital toxoplasmosis may result in non-specific consequences like abortion, intra-uterine growth restriction, jaundice, hepatosplenomegaly or even intra-uterine death. It may also result in neurological or ocular manifestations like intracranial calcifications, hydrocephalus or retinochoroiditis. The diagnosis may be done by serological screening of anti-Toxoplasma antibodies (IgM and IgG) while PCR of the amniotic fluid or the placenta is the confirmatory test. Acute or chronic infections may be differentiated by IgG avidity tests. The treatment regimens include spiramycin to prevent congenital transmission from an infected mother, pyrimethamine, sulfadoxine and folinic acid to treat the infected fetus, CSF shunting for the treatment of hydrocephalus and a combination of pyrimethamine, azithromycin, and corticosteroids for treating ocular toxoplasmosis.     

Positional cell surface antigens in an insect appendage

Summary Mice were immunized with membrane preparations of epidermal cells taken from different parts (internal and external face of femur and apex and base of tibia) of the metathoracic legs of cockroach larvae. Using indirect immunofluorescence, anti-internal face of femur antibodies were observed to bind preferentially to membranes from the internal face of the femur; similarly, anti-external face of femur antibodies bound preferentially to membranes from the external face of the femur. We also found a preferential binding of anti-apex of tibia antibodies to membranes from the apex of the tibia and anti-base of the tibia antibodies to membranes from the base of the tibia. When anti-tibia sera were tested on membranes from the femur, anti-apex of tibia antibodies bound preferentially to membranes from the apex of the femur, and anti-base of tibia antibodies bound preferentially to membranes from the base of the femur.This demonstrates that epidermal cell membranes from the different parts of the leg differ in their antigenic properties, and that these differences are related to their position around the appendage and along the proximodistal axis of segments.These results are in agreement with those of previous graft experiments and with the concept of ordered sequences in insect appendages.     

Responses of Proteolytic Enzymes in Embryonic Axes of Germinating Bean Seeds under Copper Stress

The changes in protease activities in embryonic axes during the first days of bean (Phaseolus vulgaris L.) seed germination were investigated in response to copper stress. Synthetic substrates and specific protease inhibitors have been used to define qualitatively and quantitatively different catalytic classes, particularly endoproteases (EP), carboxypeptidases (CP) and aminopeptidases (AP), then identify which ones were affected in the presence of copper. In fact, a failure in storage proteins mobilization and a disorder of nitrogen supply at enzymatic level occurred in Cu. In fact, Cu inhibited azocaseinolytic activity (ACA) and cysteine-, aspartic-, serine-, and metallo-endopeptidases activities (Cys-EP, Asp-EP, Ser-Ep, and Met-EP, respectively). Besides, Cu affected leucine- and proline-aminopeptidases (LAP and PAP, respectively) and glycine-carboxypeptidases (Gly-CP). The proteolytic responses might also be associated with the decrease in defense capacity in the Cu-treated embryos.     

Modeling of polyphenols extraction from pomegranate by-product using rotatable central composite design of experiments

There is a growing request to find an effective method of polyphenols extraction from agro-industry by-product as pomegranate. In this study, response surface methodology (RSM) was used to explore the effect of three factors on ultrasonic assisted extraction (UAE) of total polyphenols (TP), total flavonoids (TF) and condensed tannins (CT) from pomegranate peels. The optimal conditions were determined for each phenolic compound using regression model equations and 3-D plots. The high TP, TF and CT content were obtained with, respectively, liquid/solid ratio of 20.00, 9.77, 9.77, extraction time of 36.38, 41.82, 30.39 min and 36.00, 83.64, 59.26% of ethanol percentage. In fact, liquid/solid ratio of 20, extraction time of 30.94 min and 59.26% of ethanol gives the highest contents of TP, TF and CT simultaneously. The experimental values using optimal conditions agreed with the predicted values. The pomegranate peels extract obtained under optimum conditions have an effective antioxidant activity as determined by ABTS and DPPH assays.     

A gradient of interstitial Niphargus rhenorhodanensis populations in two karst/floodplain transition zones of the French Jura

The Bou-Rouch technique was used to sample two small alluvial plains in two different karst areas. One was mainly supplied by karst water (Verna), the other by both karst and surface water (Pissoir).Physical and chemical characteristics varied with time (seasons) and location of sampling sites at both stations.The distribution of Niphargus rhenorhodanensis populations was influenced by the geographical characteristics of the outlets. Only a small number of individuals was found near the outlet and none in the floodplain when the outlet was located at a base-level (Verna). Individuals were more numerous and their presence constant at all sites and dates when the outlet was located at the overflow level of the massif (Pissoir).     

Contribution à la connaissance des Encyrtidae (Hymenoptera : Chalcidoidea) du Maroc,nouvelles données et comparaison avec la faune d’Afrique du Nord

Au Maroc, la famille des Encyrtidae (Hymenoptera : Chalcidoidea) compte actuellement 46 espèces. Six genres (Acerophagus Smith, 1880, Cerchysiella Girault, 1914, Cheiloneurus Westwood, 1833, Copidosoma Ratzeburg, 1844, Epitetracnemus Girault, 1915, Tineophoctonus Ashmead, 1900) et sept espèces [Cheiloneurus elegans (Dalman, 1820), Copidosoma floridanum (Ashmead, 1900), Epitetracnemus intersectus (Fonscolombe, 1832), Habrolepis pascuorum Mercet, 1921, Metaphycus melanostomatus (Timberlake, 1916), Metaphycus castaneus (Mercet, 1921) et Tineophoctonus armatus (Ashmead, 1888)] sont signalés pour la première fois de ce pays. Les échantillonnages ont été réalisés dans trois stations d’étude au sein de la subéraie de la Maâmora au cours de deux années successives (juin 2012 à avril 2014).