ThehapC gene ofAspergillus nidulans is involved in the expression of CCAAT-containing promoters

The 5 regulatory region of theamdS gene ofAspergillus nidulans, which encodes an acetamidase required for growth on acetamide as a carbon and nitrogen source, contains a CCAAT sequence which is required for setting the basal level ofamdS expression. Mobility shift studies have identified a factor inA. nidulans nuclear extracts which binds to this CCAAT sequence. InSaccharomyces cerevisiae theHAP3 gene encodes one component of a multisubunit complex that binds CCAAT sequences. A search of the EMBL and SwissProt databases has revealed anA. nidulans sequence with significant homology to theHAP3 gene adjacent to the previously cloned regulatory geneamdR. Sequencing of the remainder of this region has confirmed the presence of a gene, designatedhapC, with extensive homology toHAP3. The predicted amino acid sequence of HapC shows extensive identity to HAP3 in the central conserved domain, but shows little conservation in the flanking sequences. A haploid carrying ahapC deletion has been created and is viable, but grows poorly on all media tested. This null mutant grows especially slowly on acetamide as a sole carbon and nitrogen source, indicating thathapC plays a role inamdS expression. In agreement with this notion, it has been shown that thehapC deletion results in reduced levels of expression of anamdS::lacZ reporter gene and this effect is particularly evident under conditions of carbon limitation. Nuclear extracts prepared from thehapC deletion mutant show no CCAAT binding activity to theamdS orgatA promoters, indicating thathapC may encode a component of the complex binding at this sequence.     

Development of acaricide resistance in Pacific spider mite (<Emphasis Type="Italic">Tetranychus pacificus</Emphasis>) from California vineyards

In recent years, grape growers in California reported failures of acaricides against Tetranychus pacificus McGregor. We collected T. pacificus populations from four vineyards and tested them for resistance to bifenazate, propargite and pyridaben. In addition, we sequenced part of the cytochrome b gene of bifenazate-resistant and -susceptible T. pacificus to test for the presence of mutations reported to confer resistance to the congeneric T. urticae. None of the mutations conferring resistance to bifenazate in T. urticae were present in resistant T. pacificus. Resistance levels ranged from full susceptibility to statistically significant 11-fold resistance to pyridaben, sevenfold resistance to bifenazate and fourfold resistance to propargite compared to a susceptible population. Despite the relatively low levels of resistance detected, we estimated that under the conditions of our study the highest field rates of bifenazate and pyridaben application would cause less than 58 and 66% mortality of adult females in the most resistant populations, respectively. In contrast, field rates of propargite application would cause close to 100% mortality in the least susceptible population. These results highlight a potential link between resistance development and reduced field effectiveness for bifenazate and pyridaben. Finally, T. pacificus may be more tolerant to bifenazate and propargite than T. urticae, since the LC₅₀ values for the susceptible population of T. pacificus were several times higher than LC₅₀’s reported for susceptible T. urticae.     

Thoracic empyema: a 12-year study from a UK tertiary cardiothoracic referral centre

Background

Empyema is an increasingly frequent clinical problem worldwide, and has substantial morbidity and mortality. Our objectives were to identify the clinical, surgical and microbiological features, and management outcomes, of empyema.

Methods

A retrospective observational study over 12 years (1999–2010) was carried out at The Heart Hospital, London, United Kingdom. Patients with empyema were identified by screening the hospital electronic ‘Clinical Data Repository’. Demographics, clinical and microbiological characteristics, underlying risk factors, peri-operative blood tests, treatment and outcomes were identified. Univariable and multivariable statistical analyses were performed.

Results

Patients (n = 406) were predominantly male (74.1%); median age = 53 years (IQR = 37–69). Most empyema were community-acquired (87.4%) and right-sided (57.4%). Microbiological diagnosis was obtained in 229 (56.4%) patients, and included streptococci (16.3%), staphylococci (15.5%), Gram-negative organisms (8.9%), anaerobes (5.7%), pseudomonads (4.4%) and mycobacteria (9.1%); 8.4% were polymicrobial. Most (68%) cases were managed by open thoracotomy and decortication. Video-assisted thoracoscopic surgery (VATS) reduced hospitalisation from 10 to seven days (P = 0.0005). All-cause complication rate was 25.1%, and 28 day mortality 5.7%. Predictors of early mortality included: older age (P = 0.006), major co-morbidity (P = 0.01), malnutrition (P = 0.001), elevated red cell distribution width (RDW, P<0.001) and serum alkaline phosphatase (P = 0.004), and reduced serum albumin (P = 0.01) and haemoglobin (P = 0.04).

Conclusions

Empyema remains an important cause of morbidity and hospital admissions. Microbiological diagnosis was only achieved in just over 50% of cases, and tuberculosis is a notable causative organism. Treatment of empyema with VATS may reduce duration of hospital stay. Raised RDW appears to associate with early mortality.     

Sexual selection under parental choice: a revision to the model

Across human cultures, parents exercise considerable influence over their children’s mate choices. The model of parental choice provides a good account of these patterns, but its prediction that male parents exercise more control than female ones is not well founded in evolutionary theory. To address this shortcoming, the present article proposes a revision to the model. In particular, parental uncertainty, residual reproductive value, reproductive variance, asymmetry in the control of resources, physical strength, and access to weaponry make control over mating more profitable for male parents than female ones; in turn, this produces an asymmetrical incentive for controlling mate choice. Several implications of this formulation are also explored.     

AnCF, the CCAAT Binding Complex of Aspergillus nidulans, Contains Products of the hapB, hapC, and hapE Genes and Is Required for Activation by the Pathway-Specific Regulatory Gene amdR

CCAAT binding factors (CBFs) positively regulating the expression of the amdS gene (encoding acetamidase) and two penicillin biosynthesis genes (ipnA and aatA) have been previously found in Aspergillus nidulans. The factors were called AnCF and PENR1, respectively. Deletion of the hapC gene, encoding a protein with significant similarity to Hap3p of Saccharomyces cerevisiae, eliminated both AnCF and PENR1 binding activities. We now report the isolation of the genes hapB and hapE, which encode proteins with central regions of high similarity to Hap2p and Hap5p of S. cerevisiae and to the CBF-B and CBF-C proteins of mammals. An additional fungus-specific domain present in HapE was revealed by comparisons with the homologs from S. cerevisiae, Neurospora crassa, and Schizosaccharomyces pombe. The HapB, HapC, and HapE proteins have been shown to be necessary and sufficient for the formation of a CCAAT binding complex in vitro. Strains with deletions of each of the hapB, hapC, and hapE genes have identical phenotypes of slow growth, poor conidiation, and reduced expression of amdS. Furthermore, induction of amdS by omega amino acids, which is mediated by the AmdR pathway-specific activator, is abolished in the hap deletion mutants, as is growth on γ-aminobutyric acid as a sole nitrogen or carbon source. AmdR and AnCF bind to overlapping sites in the promoters of the amdS and gatA genes. It is known that AnCF can bind independently of AmdR. We suggest that AnCF binding is required for AmdR binding in vivo.     

Impaired Clearance of Early Apoptotic Cells Mediated by Inhibitory IgG Antibodies in Patients with Primary Sj?gren's Syndrome

Objectives

Deficient efferocytosis (i.e. phagocytic clearance of apoptotic cells) has been frequently reported in systemic lupus erythematosus (SLE). Todate, patients with primary Sjögren''s syndrome (SS) have not been assessed for phagocytosis of apoptotic cells (ApoCell-phagocytosis) and of particulate targets (microbeads, MB-phagocytosis).

Design

ApoCell-phagocytosis and MB-phagocytosis were comparatively assessed by flow cytometry in peripheral blood specimens and monocyte-derived macrophage (MDM) preparations from healthy blood donors (HBD) and consecutive SS, SLE and rheumatoid arthritis (RA) patients. Cross-admixture ApoCell-phagocytosis experiments were also performed using phagocytes from HBD or patients, and apoptotic cells pretreated with whole sera or purified serum IgG derived from patients or HBD.

Results

Compared to HBD, approximately half of SS and SLE patients studied (but not RA) manifested significantly reduced ApoCell-phagocytosis (p<0.001) and MB-phagocytosis (p<0.003) by blood-borne phagocytes that correlated inversely with disease activity (p≤0.004). In cross-admixture assays, healthy monocytes showed significantly reduced ApoCell-phagocytosis when fed with apoptotic cells that were pretreated with sera or purified serum IgG preparations from SS and SLE patients (p<0.0001, compared to those from HBD or RA). Such aberrant effect of the SS and SLE sera and IgG preparations correlated linearly with their content of IgG antibodies against apoptotic cells (p≤0.0001). Phagocytic dysfunction maybe also present in certain SS and SLE patients, as supported by deficient capacity of MDM for ApoCell-phagocytosis and MB-phagocytosis under patients'' serum-free conditions.

Conclusion

Similarly to SLE, efferocytosis is frequently impaired in SS and is primarily due to the presence of inhibitory IgG anti-ApoCell antibodies and secondarily to phagocytes'' dysfunction.     

ThehapC gene ofAspergillus nidulans is involved in the expression of CCAAT-containing promoters

The 5′ regulatory region of theamdS gene ofAspergillus nidulans, which encodes an acetamidase required for growth on acetamide as a carbon and nitrogen source, contains a CCAAT sequence which is required for setting the basal level ofamdS expression. Mobility shift studies have identified a factor inA. nidulans nuclear extracts which binds to this CCAAT sequence. InSaccharomyces cerevisiae theHAP3 gene encodes one component of a multisubunit complex that binds CCAAT sequences. A search of the EMBL and SwissProt databases has revealed anA. nidulans sequence with significant homology to theHAP3 gene adjacent to the previously cloned regulatory geneamdR. Sequencing of the remainder of this region has confirmed the presence of a gene, designatedhapC, with extensive homology toHAP3. The predicted amino acid sequence of HapC shows extensive identity to HAP3 in the central conserved domain, but shows little conservation in the flanking sequences. A haploid carrying ahapC deletion has been created and is viable, but grows poorly on all media tested. This null mutant grows especially slowly on acetamide as a sole carbon and nitrogen source, indicating thathapC plays a role inamdS expression. In agreement with this notion, it has been shown that thehapC deletion results in reduced levels of expression of anamdS::lacZ reporter gene and this effect is particularly evident under conditions of carbon limitation. Nuclear extracts prepared from thehapC deletion mutant show no CCAAT binding activity to theamdS orgatA promoters, indicating thathapC may encode a component of the complex binding at this sequence.