Factors affecting sex ratio at birth in Croatia 1998-2008

This investigation aims to contribute to the existing literature on demographic and ecological factors affecting the sex ratio at birth, by analysing the births in Croatia from 1998 to 2008. Data from birth certificates for all Croatian births for the investigated period (n=420,256) were used to establish the link between parental ages, birth order, region of birth, parental occupation and parental education level, and sex of the child. The χ2 test and t-test were used to assess the significance of each of the factors, along with multiple logistic regression to control for possible confounding effects. The results suggest that a joint higher age of both parents significantly lowers the sex ratio at birth. There is also a regional variation in sex ratio at birth, the lowest value being in Central Croatia and the highest in the City of Zagreb. Changes in the reproductive physiology of older parents are most probably responsible for the lower sex ratio, although the limited sample size warns against widespread generalizations. The causes of the regional variation in sex ratio at birth are most likely the different regional levels of obesity and physical inactivity.     

A divalent FHA/BRCT‐binding mechanism couples the MRE11–RAD50–NBS1 complex to damaged chromatin

The MRE11–RAD50–NBS1 (MRN) complex accumulates at sites of DNA double‐strand breaks in large chromatin domains flanking the lesion site. The mechanism of MRN accumulation involves direct binding of the Nijmegen breakage syndrome 1 (NBS1) subunit to phosphorylated mediator of the DNA damage checkpoint 1 (MDC1), a large nuclear adaptor protein that interacts directly with phosphorylated H2AX. NBS1 contains an FHA domain and two BRCT domains at its amino terminus. Here, we show that both of these domains participate in the interaction with phosphorylated MDC1. Point mutations in key amino acid residues of either the FHA or the BRCT domains compromise the interaction with MDC1 and lead to defects in MRN accumulation at sites of DNA damage. Surprisingly, only mutation in the FHA domain, but not in the BRCT domains, yields a G2/M checkpoint defect, indicating that MDC1‐dependent chromatin accumulation of the MRN complex at sites of DNA breaks is not required for G2/M checkpoint activation.     

Advances in enteropathogen control in poultry production

Poultry meat has been associated frequently and consistently with the transmission of enteric pathogens, including Salmonella and Campylobacter. This association has resulted in the development of HACCP‐based intervention strategies. These strategies (hurdles) begin with elite breeder flocks and filter down the production pyramid. These hurdles include those already established, such as biosecurity, vaccination, competitive exclusion, pre‐ and probiotics, feed and water control, and those more experimental, such as bacteriophage or immunoglobulin therapy. The reduction in enteropathogens entering the processing plant, which employs critical control points, further reduce the exposure of consumers to these organisms. The synergistic application of hurdles will result in an environment that is restrictive and detrimental to enteropathogen colonization and contamination.     

Genetic diversity of three donkey populations in the Croatian coastal region

Genetic variation in three Croatian donkey populations, Istrian (IS), North Adriatic (NA) and Littoral-Dinaric (LD), was analysed using eight microsatellite loci and by sequence and SSCP analysis of the proximal portion of the mtDNA D-loop region. The analysis of microsatellite loci revealed observed heterozygosities in the range of 0.37 (MPZ002 in LD) to 0.85 (AHT21 in LD) and polymorphic information content values in the range of 0.36 (MPZ002 in NA) to 0.78 (AHT21 in LD). The overall probability of exclusion was 0.991. Two populations (IS and NA) were closely related (Fst=0.0034), whereas genetic distances between IS and LD (Fst=0.021) and NA and LD (Fst=0.027) were higher. Using AMOVA, 97.6% of the total genetic variance was portioned within populations, while 2.7% was portioned between the Littoral-Dinaric population and the Istrian/North Adriatic population group. Sequencing of the proximal part of the mtDNA D-loop region revealed 36 polymorphic sites representing 19 haplotypes which clustered into three haplotype groups (Y, W, Ws). Only the Y haplotype was found in the IS population which is characterized by a large body size. Haplotypes W and Ws were found in the NA and LD populations which include smaller animals. All three haplotypes were found in the LD population, indicating sporadic migration events from the IS into LD donkey population.     

The PP2A-Integrator-CDK9 axis fine-tunes transcription and can be targeted therapeutically in cancer

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Classification of Salmonella enterica serotypes from Australian poultry using repetitive sequence-based PCR

Aims: To evaluate a semi‐automated repetitive extragenic palindromic sequence‐based PCR (rep‐PCR) system for the classification of Salmonella serotypes from Australian poultry. Methods and Results: Using a DNA fingerprint library within the DiversiLab^® System, four separate databases were constructed (serogroup B, C, E and Other). These databases contained 483 serologically confirmed (reference laboratory) Salmonella isolates. A blinded set of Salmonella cultures (n = 155) were typed by rep‐PCR, matched against the internal library and compared with traditional serotyping. The predicted (Kullback–Leibler) serotype of 143 (92·3%) isolates matched traditional typing (P < 0·05). Of the 12 (7·7%) remaining isolates, ten (6·5%) resulted in ‘No Match’, one (0·65%) was incorrectly matched to the library (Salm. subsp 1 ser 4,12:‐:‐), and the other (0·65%) was referenced as Salm. ser. Sofia, whereas rep‐PCR and in‐house serotyping concurred as Salmonella serovar Typhimurium. Financial analysis showed higher material cost (215%) and a lower labour component (47·5%) for rep‐PCR compared with serotyping. Conclusion: The DiversiLab^® System, with serogroup databases, was successfully implemented as an adjunct for reference serotyping of Salmonella enterica. Significance and Impact of the Study: The DiversiLab^® System platform is a cost‐effective and easy‐to‐use system, which can putatively determine Salmonella enterica serotypes within a few hours.     

Genetics of resistance to phosphine in Rhyzopertha dominica (Coleoptera: Bostrichidae)

The inheritance of resistance to phosphine was studied in two strains of the lesser grain borer, Rhyzopertha dominica (F.), labeled 'Weak-R' and 'Strong-R'. These strains were purified versions of field-selected populations collected in Queensland, Australia. Weak-R and Strong-R were, respectively, 23.4 times (20-h exposure) and 600 times (48-h exposure) resistant to phosphine compared with a reference susceptible strain (S-strain). Each -R strain was crossed with the S-strain and the response to phosphine was measured in their respective F1, F2, and F1-backcross (F1-BC) progenies. Data from testing of reciprocal F1 progeny indicated that resistance in Weak-R was autosomal and incompletely recessive with a degree of dominance -0.96. Modified chi-square analysis and contingency analysis of the observed response to phosphine of F1-BC and F2 progenies rejected the hypothesis of single gene inheritance of resistance. Analysis of the response of the F1, F2, and F1-BC progeny from the Strong-R x S-strain cross also rejected the null hypothesis for single gene resistance. Resistance in the Strong-R strain was autosomal and incompletely recessive with a degree of dominance of -0.64. The Weak-R and Strong-R strains were then crossed. Analysis ofthe F1 and F2 progenies of this reciprocal cross revealed that the strong resistance phenotype was coded by a combination of the genes already present in the Weak-R genotype plus an extra major, incompletely recessive gene. There was also evidence of a minor dominant gene present in approximately 5% of Strong-R individuals.     

The metastasis-promoting phosphatase PRL-3 shows activity toward phosphoinositides

Phosphatase of regenerating liver 3 (PRL-3) is suggested as a biomarker and therapeutic target in several cancers. It has a well-established causative role in cancer metastasis. However, little is known about its natural substrates, pathways, and biological functions, and only a few protein substrates have been suggested so far. To improve our understanding of the substrate specificity and molecular determinants of PRL-3 activity, the wild-type (WT) protein, two supposedly catalytically inactive mutants D72A and C104S, and the reported hyperactive mutant A111S were tested in vitro for substrate specificity and activity toward phosphopeptides and phosphoinositides (PIPs), their structural stability, and their ability to promote cell migration using stable HEK293 cell lines. We discovered that WT PRL-3 does not dephosphorylate the tested phosphopeptides in vitro. However, as shown by two complementary biochemical assays, PRL-3 is active toward the phosphoinositide PI(4,5)P(2). Our experimental results substantiated by molecular docking studies suggest that PRL-3 is a phosphatidylinositol 5-phosphatase. The C104S variant was shown to be not only catalytically inactive but also structurally destabilized and unable to promote cell migration, whereas WT PRL-3 promotes cell migration. The D72A mutant is structurally stable and does not dephosphorylate the unnatural substrate 3-O-methylfluorescein phosphate (OMFP). However, we observed residual in vitro activity of D72A against PI(4,5)P(2), and in accordance with this, it exhibits the same cellular phenotype as WT PRL-3. Our analysis of the A111S variant shows that the hyperactivity toward the unnatural OMFP substrate is not apparent in dephosphorylation assays with phosphoinositides: the mutant is completely inactive against PIPs. We observed significant structural destabilization of this variant. The cellular phenotype of this mutant equals that of the catalytically inactive C104S mutant. These results provide a possible explanation for the absence of the conserved Ser of the PTP catalytic motif in the PRL family. The correlation of the phosphatase activity toward PI(4,5)P(2) with the observed phenotypes for WT PRL-3 and the mutants suggests a link between the PI(4,5)P(2) dephosphorylation by PRL-3 and its role in cell migration.