Atorvastatin effects on SREBF1a and SCAP gene expression in mononuclear cells and its relation with lowering-lipids response

Background: The transcription factors SREBP1 and SCAP are involved in intracellular cholesterol homeostasis. Polymorphisms of these genes have been associated with variations on serum lipid levels and response to statins that are potent cholesterol-lowering drugs. We evaluated the effects of atorvastatin on SREBF1a and SCAP mRNA expression in peripheral blood mononuclear cells (PBMC) and a possible association with gene polymorphisms and lowering-cholesterol response. Methods: Fifty-nine hypercholesterolemic patients were treated with atorvastatin (10 mg/day for 4 weeks). Serum lipid profile and mRNA expression in PBMC were assessed before and after the treatment. Gene expression was quantified by real-time PCR using GAPD as endogenous reference and mRNA expression in HepG2 cells as calibrator. SREBF1 -36delG and SCAP A2386G polymorphisms were detected by PCR-RFLP. Results: Our results showed that transcription of SREBF1a and SCAP was coordinately regulated by atorvastatin (r=0.595, p<0.001), and that reduction in SCAP transcription was associated with the 2386AA genotype (p=0.019). Individuals who responded to atorvastatin with a downregulation of SCAP had also a lower triglyceride compared to those who responded to atorvastatin with an upregulation of SCAP. Conclusion: Atorvastatin has differential effects on SREBF1a and SCAP mRNA expression in PBMC that are associated with baseline transcription levels, triglycerides response to atorvastatin and SCAP A2386G polymorphism. (c) 2008 Elsevier B.V. All rights reserved.

Biophysical characterization of the recombinant merozoite surface protein-3 of Plasmodium vivax

Plasmodium vivax Merozoite Surface Protein-3 alpha and 3 beta are members of a family of related merozoite surface proteins that contain a central alanine-rich domain with heptad repeats that is predicted to form alpha-helical secondary and coiled-coil tertiary structures. Seven recombinant proteins representing different regions of MSP-3 alpha and MSP-3 beta of P. vivax were generated to investigate their structure. Circular dichroism spectra analysis revealed that some proteins are folded with a high degree of alpha-helices as secondary structure, whereas other products contain a high content of random coil. Using size exclusion chromatography, we found that the two smaller fragments of the MSP-3 alpha, named CC4 and CC5, predicted to form coiled-coil (CC) structures, eluted at volumes corresponding to molecular weights larger than their monomeric masses. This result suggests that both proteins are oligomeric molecules. Analytical ultracentrifugation experiments showed that the CC5 oligomers are elongated molecules. Together, these data may help to understand important aspects of P. vivax biology. (C) 2008 Elsevier B.V. All rights reserved.

Tripalmitin and monoacylglycerols as modifiers in the crystallisation of palm oil

An exhaustive analysis of the crystallisation behaviour of palm oil was performed using low-resolution magnetic pulsed nuclear resonance, differential scanning calorimetry, polarised light microscopy and X-ray diffraction. The aim of this study was to characterise the changes induced in the crystallisation of palm oil by the addition of two different levels of tripalmitin and two different types of monoacylglycerols. The addition of monoacylglycerols led to the formation of a large number of crystallisation nuclei without changing the final solids content, accelerating the process of crystal formation, leading to the formation of smaller crystals than those found in the refined palm oil. Higher levels of tripalmitin produced crystals with larger dimensions, reducing the induction period and resulted in a higher level of solids at the end of the crystallisation period. The addition of monoacylglycerols and tripalmitin induced the formation of a polymorphic beta-form. (C) 2010 Elsevier Ltd. All rights reserved.

Transcript profiling of papaya fruit reveals differentially expressed genes associated with fruit ripening

Papaya (Carica papaya L) fruit has a short shelf life due to fast ripening induced by ethylene, but little is known about the genetic control of ripening and attributes of fruit quality. Therefore, we identified ripening-related genes affected by ethylene using cDNA-AFLP (Amplified Fragment Length Polymorphism of cDNA). Transcript profiling of non-induced and ethylene-induced fruit samples was performed, and 71 differentially expressed genes were identified. Among those genes some involved in ethylene biosynthesis, regulation of transcription, and stress responses or plant defence were found (heat shock proteins, polygalacturonase-inhibiting protein, and acyl-CoA oxidases). Several transcription factors were isolated, and except for a 14-3-3 protein, an AP2 domain-containing factor, a salt-tolerant zinc finger protein, and a suppressor of PhyA-105 1, most of them were negatively affected by ethylene, including fragments of transcripts similar to VRN1, and ethylene responsive factors (ERF). With respect to fruit quality, genes related to cell wall structure or metabolism, volatiles or pigment precursors, and vitamin biosynthesis were also found. (C) 2010 Elsevier Ireland Ltd. All rights reserved.

ABCB1 and ABCC1 expression in peripheral mononuclear cells is influenced by gene polymorphisms and atorvastatin treatment

This study investigated the effects of atorvastatin on ABCB1 and ABCC1 mRNA expression on peripheral blood mononuclear cells (PBMC) and their relationship with gene polymorphisms and lowering-cholesterol response. one hundred and thirty-six individuals with hypercholesterolemia were selected and treated with atorvastatin (10 mg/day/4 weeks). Blood samples were collected for serum lipids and apolipoproteins measurements and DNA and RNA extraction. ABCB1 (C3435T and G2677T/A) and ABCC1 (G2012T) gene polymorphisms were identified by polymerase chain reaction-restriction (PCR)-RFLP and mRNA expression was measured in peripheral blood mononuclear cells by singleplex real-time PCR. ABCB1 polymorphisms were associated with risk for coronary artery disease (CAD) (p < 0.05). After atorvastatin treatment, both ABCB1 and ABCC1 genes showed 50% reduction of the mRNA expression (p < 0.05). Reduction of ABCB1 expression was associated with ABCB1 G2677T/A polymorphism (p = 0.039). Basal ABCB1 mRNA in the lower quartile (<0.024) was associated with lower reduction rate of serum low-density lipoprotein (LDL) cholesterol (33.4 +/- 12.4%) and apolipoprotein B (apoB) (17.0 +/- 31.3%) when compared with the higher quartile (>0.085: LDL-c = 40.3 +/- 14.3%; apoB = 32.5 +/- 10.7%; p < 0.05). ABCB1 substrates or inhibitors did not affect the baseline expression, while ABCB1 inhibitors reversed the effects of atorvastatin on both ABCB1 and ABCC1 transporters. In conclusion, ABCB1 and ABCC1 mRNA levels in PBMC are modulated by atorvastatin and ABCB1 G2677T/A polymorphism. and ABCB1 baseline expression is related to differences in serum LDL cholesterol and apoB in response to atorvastatin. (C) 2008 Elsevier Inc. All rights reserved.

Cdc42p controls yeast-cell shape and virulence of Paracoccidioides brasiliensis

Paracoccidioides brasiliensis is characterized by a multiple budding phenotype and a polymorphic cell growth, leading to the formation of cells with extreme variations in shape and size. Since Cdc42 is a pivotal molecule in establishing and maintaining polarized growth for diverse cell types, as well as during pathogenesis of certain fungi, we evaluated its role during cell growth and virulence of the yeast-form of P. brasiliensis. We used antisense technology to knock-down PbCDC42`s expression in P. brasiliensis yeast cells, promoting a decrease in cell size and more homogenous cell growth, altering the typical polymorphism of wild-type cells. Reduced expression levels also lead to increased phagocytosis and decreased virulence in a mouse model of infection. We provide genetic evidences underlying Pbcdc42p as an important protein during host-pathogen interaction and the relevance of the polymorphic nature and cell size in the pathogenesis of P. brasiliensis. (C) 2009 Elsevier Inc. All rights reserved.

Assessment of how pregnancy modifies plasma lead and plasma/whole blood lead ratio in ALAD 1-1 genotype women

Pregnant women are one of the most sensitive populations to the toxic effects associated with lead (Pb) exposure. These effects are primarily associated with plasma Pb (Pb-P), which reflects the most rapidly exchangeable fraction of Pb in the bloodstream, and elevated maternal Pb-P may be more relevant to foetal Pb exposure than whole blood Pb (Pb-B). We investigated how pregnancy affects Pb-B, Pb-P and %Pb-P/Pb-B ratios without the influence of the 6-aminolevulinic acid dehydratase (ALAD) G177C polymorphism, which is a major genetic factor influencing Pb-B, Pb-P and %Pb-P/Pb-B ratios. Genotypes for the ALAD G177C polymorphism were determined by PCR and restriction fragment length digestion in nine pregnant and 20 non-pregnant women, aged 18-33, environmentally exposed to Pb. Here, we included only women with ALAD 1-1 genotype. Pb-P and Pb-B were determined by inductively coupled plasma mass spectrometry and by graphite furnace atomic absorption spectrometry, respectively. We found no differences in Pb-B (P > 0.05). However, pregnant women had a 2-fold increase in Pb-P and a 3-fold increase in %Pb-P/Pb-B (both P < 0.01) compared to nonpregnant women. These alterations in Pb concentrations associated with pregnancy are similar to those associated with different ALAD gene variants. We can now better appreciate how pregnancy affects foetal exposure to Pb without the influence of this important genetic factor.

Haplotypes of vitamin D receptor modulate the circulating levels of lead in exposed subjects

Genetic factors influence whole blood lead (Pb-B) concentrations in lead exposed subjects. This study aimed at examining the combined effects (haplotype analysis) of three polymorphisms (BsmI, ApaI and FokI) in vitamin D receptor (VDR) gene on Pb-B and on the concentrations of lead in plasma (Pb-P), which is more relevant to lead toxicity, in 150 environmentally exposed subjects. Genotypes were determined by RFLP, and Pb-P and Pb-B were determined by inductively coupled plasma mass spectrometry and by graphite furnace atomic absorption spectrometry, respectively. Subjects with the bb (BsmI polymorphism) or ff (FokI polymorphism) genotypes have lower B-Pb than subjects in the other genotype groups. Subjects with the aa (ApaI polymorphism) or ff genotypes have lower P-Pb than subjects in the other genotype groups. Lower Pb-P, Pb-B, and %Pb-P/Pb-B levels were found in subjects with the haplotype combining the a, b, and f alleles for the ApaI, BsmI, and FokI polymorphisms, respectively, compared with the other haplotype groups, thus suggesting that VDR haplotypes modulate the circulating levels of lead in exposed subjects.

Allelic Variation Investigation of the Estrogen Receptor Within an Australian Multiple Sclerosis Population

Multiple Sclerosis (MS) is a central nervous system (CNS) chronic inflammatory demyelinating disease leading to various neurological disabilities. The disorder is more prevalent for women with a ratio of 3:2 female to male. Objectives: To investigate variation within the estrogen receptor 1 (ESR1) polymorphism gene in an Australian MS case-control population using two intragenic restriction fragment length polymorphisms; the G594A located in exon 8 detected with the BtgI restriction enzyme and T938C located in intron 1, detected with PvuII. One hundred and ten Australian MS patients were studied, with patients classified clinically as Relapsing Remitting MS (RR-MS), Secondary Progressive MS (SP-MS) or Primary Progressive MS (PP-MS). Also, 110 age, sex and ethnicity matched controls were investigated as a comparative group. No significant difference in the allelic distribution frequency was found between the case and control groups for the ESR1 PvuII (P = 0.50) and Btg1 (P = 0.45) marker. Our results do not support a role for these two ESR1 markers in multiple sclerosis susceptibility, however other markers within ESR1 should not be excluded for potential involvement in the disorder.

No Association Between MTHFR A1298C and MTRR A66G Polymorphisms, and MS in an Australian Cohort

Multiple sclerosis (MS) is a complex neurological disease that affects the central nervous system (CNS) resulting in debilitating neuropathology. Pathogenesis is primarily defined by CNS inflammation and demyelination of nerve axons. Methionine synthase reductase (MTRR) is an enzyme that catalyzes the remethylation of homocysteine (Hcy) to methionine via cobalamin and folate dependant reactions. Cobalamin acts as an intermediate methyl carrier between methylenetetrahydrofolate reductase (MTHFR) and Hcy. MTRR plays a critical role in maintaining cobalamin in an active form and is consequently an important determinant of total plasma Hcy (pHcy) concentrations. Elevated intracellular pHcy levels have been suggested to play a role in CNS dysfunction, neurodegenerative, and cerebrovascular diseases. Our investigation entailed the genotyping of a cohort of 140 cases and matched controls for MTRR and MTHFR, by restriction length polymorphism (RFLP) techniques. Two polymorphisms: MTRR A66G and MTHFR A1298C were investigated in an Australian age and gender matched case-control study. No significant allelic frequency difference was observed between cases and controls at the α = 0.05 level (MTRR χ^2 = 0.005, P = 0.95, MTHFR χ^2 = 1.15, P = 0.28). Our preliminary findings suggest no association between the MTRR A66G and MTHFR A1298C polymorphisms and MS.

Cytoplasmic incompatibility in Drosophila populations: influence of assortative mating on symbiont distribution

Cytoplasmic incompatibility is known to occur between strains of both Drosophila simulans and D. melanogaster. Incompatibility is associated with the infection of Drosophila with microorganismal endosymbionts. This paper reports survey work conducted on strains of D. simulans and D. melanogaster from diverse geographical locations finding that infected populations are relatively rare and scattered in their distribution. The distribution of infected populations of D. simulans appears to be at odds with deterministic models predicting the rapid spread of the infection through uninfected populations. Examination of isofemale lines from four localities in California where populations appear to be polymorphic for the infection failed to find evidence for consistent assortative mating preferences between infected and uninfected populations that may explain the basis for the observed polymorphism.

Positive selection on an acrosomal sperm protein, M7 lysin, in three species of the mussel genus Mytilus

Marine invertebrate sperm proteins are particularly interesting because they are characterized by positive selection and are likely to be involved in prezyogotic isolation and, thus, speciation. Here, we present the first survey of inter and intraspecific variation of a bivalve sperm protein among a group of species that regularly hybridize in nature. M7 lysin is found in sperm acrosomes of mussels and dissolves the egg vitelline coat, permitting fertilization. We sequenced multiple alleles of the mature protein-coding region of M7 lysin from allopatric populations of mussels in the Mytilus edulis species group (M. edulis, M. galloprovincialis, and M. trossulus). A significant McDonald-Kreitman test showed an excess of fixed amino acid replacing substitutions between species, consistent with positive selection. In addition, Kolmogorov-Smirnov tests showed significant heterogeneity in polymorphism to divergence ratios for both synonymous variation and combined synonymous and non-synonymous variation within M. galloprovincialis. These results indicate that there has been adaptive evolution at M7 lysin and, furthermore, shows that positive selection on sperm proteins can occur even when post-zygotic reproductive isolation is incomplete.

When oceans meet: a teleost shows secondary intergradation at an Indian-Pacific interface

The Indo-West Pacific is characterized by extraordinary marine species diversity. The evolutionary mechanisms responsible for generating this diversity remain puzzling, but are often linked to Pleistocene sea level fluctuations. The impact of these sea level changes on the population genetic architecture of the estuarine fish Lates calcarifer are investigated via a natural experiment in a region of the Indo-West Pacific known to have undergone considerable change during the Pleistocene. L. calcarifer, a coastline-restricted catadromous teleost, provides an excellent model for studying the effects of sea level change as its habitat requirements potentially make it sensitive to the region's physical history. Evidence was found for a large phylogenetic break (4% mtDNA control region; 0.47% ATPase 6 and 8) either side of the Torres Strait, which separates the Western Pacific and Indian Oceans, although some mixing of the clades was evident. This suggests clinal secondary introgression of the clades via contemporary gene flow. Further, populations on Australia's east coast appear to have passed through a bottleneck. This was linked to the historical drying of the Great Barrier Reef coastal lagoon, which resulted in a significant loss of habitat and forced retreat into isolated refugia. These results suggest that historical eustatic changes have left a significant imprint on the molecular diversity within marine species as well as among them in the Indo-West Pacific.

FRA10B structure reveals common elements in repeat expansion and chromosomal fragile site genesis

A common mechanism for chromosomal fragile site genesis is not yet apparent. Folate-sensitive fragile sites are expanded p(CCG)n repeats that arise from longer normal alleles. Distamycin A or bromodeoxyuridine-inducible fragile site FRA16B is an expanded AT-rich similar to 33 bp repeat; however, the relationship between normal and fragile site alleles is not known. Here, we report that bromodeoxyuridine-inducible, distamycin A-insensitive fragile site FRA10B is composed of expanded similar to 42 bp repeats. Differences in repeat motif length or composition between different FRA10B families indicate multiple independent expansion events. Some FRA10B alleles comprise a mixture of different expanded repeat motifs. FRA10B fragile site and long normal alleles share flanking polymorphisms. Somatic and intergenerational FRA10B repeat instability analogous to that found in expanded trinucleotide repeats supports dynamic mutation as a common mechanism for repeat expansion.

A global marker database for Phytophthora infestans

A marker database was compiled for isolates of the potato and tomato late blight pathogen, Phytophthora infestans, originating from 41 locations which include 31 countries plus 10 regions within Mexico. Presently, the database contains information on 1,776 isolates for one or more of the following markers: restriction fragment length polymorphism (RFLP) fingerprint consisting of 23 bands; mating type; dilocus allozyme genotype; mitochondrial DNA haplotype; sensitivity to the fungicide metalaxyl; and virulence. In the database, 305 entries have unique RFLP fingerprints and 258 entries have unique multilocus genotypes based on RFLP fingerprint, dilocus allozyme genotype, and mating type. A nomenclature is described for naming multilocus genotypes based on the International Organization for Standardization (ISO) two-letter country code and a unique number, Forty-two previously published multilocus genotypes are represented in the database with references to publications. As a result of compilation of the database, seven new genotypes were identified and named. Cluster analysis of genotypes from clonally propagated populations worldwide generally confirmed a previously published classification of old and new genotypes. Genotypes from geographically distant countries were frequently clustered, and several old and new genotypes were found in two or more distant countries. The cluster analysis also demonstrated that A2 genotypes from Argentina differed from all others. The database is available via the Internet, and thus can serve as a resource for Phytophthora workers worldwide.