Candida albicans GRX2, encoding a putative glutaredoxin, is required for virulence in a murine model

Resistance of Candida albicans to reactive oxygen species is thought to enhance its virulence in mammalian hosts. Genes such as SOD1, which encodes the anti-oxidant, superoxide dismutase, are known virulence factors. We disrupted the gene GRX2, which encodes a putative glutathione reductase (glutaredoxin) in C. albicans, and we compared the mutant with an sod1Deltamutant. In vitro, the grx2Deltastrain, but not the sod1Delta strain, was defective in hypha formation. The grx2Deltastrain, but not sod1Delta, was significantly more susceptible to killing by neutrophils. When exposed to two compounds that generate reactive oxygen species, both mutants were susceptible to 1 mM menadione, but grx2Deltanull alone was resistant to diamide. Both mutants were attenuated in a murine intravenous challenge model, and a GRX2 reintegrant regained partial virulence. Emphasis on the putative function of products of genes such as SOD1 and GRX2 in resistance to oxidative stress may oversimplify their functions in the virulence process, since the grx2Deltastrain also gave defective hypha formation. Both mutants were sensitive to menadione and were slow to form germ tubes, though growth rates matched controls once the lag phase was passed.     

A two-dimensional proteome reference map of Herbaspirillum seropedicae proteins

Herbaspirillum seropedicae is an endophytic diazotroph associated with economically important crops such as rice, sugarcane, and wheat. Here, we present a 2-D reference map for H. seropedicae. Using MALDI-TOF-MS we identified 205 spots representing 173 different proteins with a calculated average of 1.18 proteins/gene. Seventeen hypothetical or conserved hypothetical ORFs were shown to code for true gene products. These data will support the genome annotation process and provide a basis on which to undertake comparative proteomic studies.     

Gestational jet lag predisposes to later-life skeletal and cardiac disease

Circadian rhythm disturbance (CRD) increases the risk of disease, e.g. metabolic syndrome, cardiovascular disease, and cancer. In the present study, we investigated later life adverse health effects triggered by repeated jet lag during gestation. Pregnant mice were subjected to a regular light-dark cycle (CTRL) or to a repeated delay (DEL) or advance (ADV) jet lag protocol. Both DEL and ADV offspring showed reduced weight gain. ADV offspring had an increased circadian period, and an altered response to a jet lag was observed in both DEL and ADV offspring. Analysis of the bones of adult male ADV offspring revealed reduced cortical bone mass and strength. Strikingly, analysis of the heart identified structural abnormalities and impaired heart function. Finally, DNA methylation analysis revealed hypermethylation of miR17-92 cluster and differential methylation within circadian clock genes, which correlated with altered gene expression. We show that developmental CRD affects the circadian system and predisposes to non-communicable disease in adult life.     

The ovarian and uterine responses of Baixadeiro mares to prostaglandin synchronization during the dry and rainy seasons

This study aimed to evaluate the effect of synchronization with prostaglandin F2α in Baixadeiro mares during the rainy and dry seasons. Fourteen mares were synchronized by administering two doses of 1 mL prostaglandin PGF 2α and monitored by rectal palpation and ultrasound for the assessment of follicular development and uterine echotexture. Of this total, nine mares allowed the collection of blood, in which the blood was collected by venipuncture of the jugular vein to determine progesterone (P4) by ELISA. Mares showed no differences (P > 0.05) in weight, body score condition (BSC), tone, uterine edema, frequency of ovulation, synchronization interval, estrus, and the total number of follicles between periods. However, there was a difference in large increased follicle diameter (P < 0.05) during the dry season. The average concentrations of P4 in mares differed (P < 0.05) between the pre- and post-ovulatory phases for both seasons and after ovulation, with higher concentrations in the rainy season. Furthermore, statistical differences in daily light (P < 0.05) were observed between the dry and rainy periods. Thus, we conclude that mares from the genetic grouping Baixadeiro showed no reproductive seasonality, though there was a difference in luminosity between the rainy and dry seasons. The treatment with two doses of PGF 2α was effective in synchronizing the mares, promoting the return of estrus in the dry and rainy periods. The mares remaining cyclically active throughout the year provided there were appropriate forage availability and quality levels to allow for normal values of body weight and condition.     

The place of Callimico goeldii in the Callitrichine phylogenetic tree: evidence from von Willebrand factor gene intron II sequences

Sequences of a 0.9-kb DNA segment spanning intron 11 of the von Willebrand Factor gene (vWF) were determined for 21 individuals of 19 primate species. The results of maximum parsimony and maximum likelihood analyses of these vWF sequences are congruent with previous molecular findings from other nonlinked nuclear genomic loci which divide the platyrrhine superfamily Ceboidea into three monophyletic families: Cebidae, Atelidae, and Pitheciidae. The vWF results strongly support the taxon Callitrichinae as a monophyletic subfamily within Cebidae. The four extant callitrichine genera constitute tribe Callitrichini, and the basal branchings within this tribe first separate out Saguinus (tamarins), next Leontopithecus (lion tamarins), and last the sister genera Callimico (Goeldi's monkeys) and Callithrix (marmosets). Callithrix divides into three subclades, with pygmy marmosets (C. pygmaea) as sister of the C. argentata species group and with the C. jacchus species group as their sister. Fossil and DNA evidence place the emergence of the callitrichine clade in the basal cebid radiation at about 20 Ma (million years ago) and the three basal branchings in the callitrichin radiation at about 13 to 11 Ma. In turn, the branchings separating the three subclades of Callithrix are placed at about 5 to 4 Ma.     

The use of ferromagnetic Dacron as solid-phase in chemiluminescent assays

Ferromagnetic Dacron hydrazide particles (63–74 m) were activated either by converting hydrazide groups to azide or binding glutaraldehyde to the hydrazide groups. Human serum albumin (HSA) was immobilised to the activated matrices and antibodies against HSA were detected by using the chemiluminescent assay. The use of these particles (either Dacron-azide or Dacron-glutaraldehyde) gave similar results compared with the paramagnetic particles commercially available from Ciba Corning.     

Hypoosmotic test in equine spermatozoa

The aim of the study was to evaluate equine sperm membrane integrity using the hypoosmotic swelling (HOS) test and to correlate this test with different sperm parameters in raw and frozen thawed semen. The HOS solutions were made with fructose, sucrose, lactose and sodium citrate each at 300, 150, 100, 50 and 25 mosm. Maximum numbers of swollen spermatozoa were observed in solutions of fructose, sucrose and lactose each at 100, 50 and 25 mosm. Correlations between progressive motility, morphologically normal spermatozoa and the HOS test were r = 0.75 and r = 0.51 in raw semen and r = 0.26 and r = -0.22 in frozen-thawed semen. The correlation between HOS and percentage of intact membranes with the fluorescent stain was r = 0.32 in frozen-thawed semen. The HOS test is a simple and accessible method which could be used as a complement to routine equine semen analysis. It has the added advantages of being less susceptible to the immediate effects of cold shock and of evaluating individual spermatozoa rather than the population as a whole, as does progressive motility.     

Distribution of Chitinases in the Entomopathogen <Emphasis Type="Italic">Metarhizium anisopliae</Emphasis> and Effect of <Emphasis Type="Italic">N</Emphasis>-Acetylglucosamine in Protein Secretion

For a long time, fungi have been characterized by their ability to secrete enzymes, mostly hydrolytic in function, and thus are defined as extracellular degraders. Chitin and chitinolytic enzymes are gaining importance for their biotechnological applications. Particularly, chitinases are used in agriculture to control plant pathogens. Metarhizium anisopliae produces an extracellular chitinase when grown on a medium containing chitin, indicating that synthesis is subject to induction by the substrate. Various sugar combinations were investigated for induction and repression of chitinase. N-acetylglucosamine (GlcNAc) shows a special dual regulation on chitinase production. M. anisopliae has at least two distinct, cell-bound, chitinolytic enzymes when cultured with GlcNAc as one of the carbon sources, and we suggest that this carbohydrate has an important role in protein secretion.