SPO71 mediates prospore membrane size and maturation in Saccharomyces cerevisiae.

The mechanisms that control the size and shape of membranes are not well understood, despite the importance of these structures in determining organelle and cell morphology. The prospore membrane, a double lipid bilayer that is synthesized de novo during sporulation in S. cerevisiae, grows to surround the four meiotic products. This membrane determines the shape of the newly formed spores and serves as the template for spore wall deposition. Ultimately, the inner leaflet of the prospore membrane will become the new plasma membrane of the cell upon germination. Here we show that Spo71, a pleckstrin homology domain protein whose expression is induced during sporulation, is critical for the appropriate growth of the prospore membrane. Without SPO71, prospore membranes surround the nuclei but are abnormally small, and spore wall deposition is disrupted. Sporulating spo71Δ cells have prospore membranes that properly localize components to their growing leading edges yet cannot properly localize septin structures. We also found that SPO71 genetically interacts with SPO1, a gene with homology to the phospholipase B gene that has been previously implicated in determining the shape of the prospore membrane. Together, these results show that SPO71 plays a critical role in prospore membrane development.

Differentiating Tower of Hanoi performance: interactive effects of psychopathic tendencies, impulsive response styles, and modality.

Previous research has demonstrated that performance on the computerized Tower of Hanoi is lower than performance on the manual Tower of Hanoi. The present study was conducted to elucidate potential factors that contribute to performance differences across modalities. Personality characteristics related to psychopathy and impulsive response styles were hypothesized to be correlates of poor performance on the computerized version of the Tower of Hanoi, which is a problem-solving task that requires working memory, planning, and inhibition. Eighty-four college students from a mid-sized university participated. Participants were grouped as low, middle, or high psychopathy based on their total scores on the Psychopathic Personality Inventory. A 2 (Modality) × 3 (Psychopathy) analysis of covariance, controlling for visuospatial working memory, yielded a significant interaction, in which the high psychopathy group did not differ in performance across modality, whereas the low and middle psychopathy groups performed more poorly on the computerized version. Subsequent analyses on reaction time and accuracy for the computerized modality indicated that a reflective, methodical approach to the computerized task was more productively utilized in the low psychopathy group, whereas the fast and accurate approach was more productively utilized in the high psychopathy group. These results suggest that individuals with elevated psychopathic tendencies within a normal population are not necessarily deficient in problem-solving performance on the Tower of Hanoi. Impulsive responding is associated with poor performance in the computerized version of the Tower of Hanoi, irrespective of psychopathic tendencies. Caution should be exercised in interpreting scores on the computerized Tower of Hanoi because the psychometric properties required for comparability with the manual version have not been sufficiently demonstrated.

SERPINA3 (aka alpha-1-antichymotrypsin).

Recent advances in proteomic, transcriptomic and genomic technologies have revealed much about the ACT protein and gene. In this review, we summarize our current understanding of the structure and potential physiological roles of the ACT protein, catalogue the regulatory elements that have been implicated in expression of the ACT gene, describe its tissue-specific expression and list the single nucleotide polymorphisms (SNPs) within the gene that track ACT variability. The ACT gene has been implicated in a number of complex human disorders and its potential involvement as a risk factor for Alzheimer's disease has been the subject of intensive research. However, due to previous limitations in methodologies and inadequate sample numbers the data has been conflicting with many studies failing to be replicated. In this regard, we highlight some potential approaches, which may prove to be beneficial in future studies.

Effects of Alzheimer's peptide and alpha1-antichymotrypsin on astrocyte gene expression.

We employed gene array technology to investigate the effects of alpha1-antichymotrypsin (ACT), soluble or fibrillar Alzheimer's peptide (Abeta(1-42)) alone and the combination of ACT/Abeta(1-42) on human astrocytes. Using a 1.2-fold change as significance threshold, 398 astrocyte genes showed altered expression in response to these treatments compared to controls. Of the 276 genes affected by the ACT/soluble Abeta(1-42) combination, 195 (70.6%) were suppressed. The ACT/fibrillar Abeta(1-42) combination affected expression of 64 genes of which 58 (90.5%) were up-regulated. The most prominent gene expression changes in response to the ACT/soluble Abeta(1-42), were the down-regulation of at least 60 genes involved in transcription, signal transduction, apoptosis and neurogenesis. The ACT/fibril Abeta(1-42) increased the expression of genes involved in transcription regulation and signal transduction. Surprisingly, gene expression of astrocytes exposed to soluble or fibrillar Abeta(1-42) alone was largely unaffected. Thus, the molecular forms generated by the combination of ACT/Abeta(1-42) alter expression of astrocyte genes more profoundly in breadth and magnitude than soluble or fibrillar Abeta(1-42) alone, suggesting that pathogenic effects of Abeta(1-42) may occur as a consequence of its association with other proteins.

Positional cloning of a novel gene influencing asthma from chromosome 2q14.

Asthma is a common disease in children and young adults. Four separate reports have linked asthma and related phenotypes to an ill-defined interval between 2q14 and 2q32 (refs. 1-4), and two mouse genome screens have linked bronchial hyper-responsiveness to the region homologous to 2q14 (refs. 5,6). We found and replicated association between asthma and the D2S308 microsatellite, 800 kb distal to the IL1 cluster on 2q14. We sequenced the surrounding region and constructed a comprehensive, high-density, single-nucleotide polymorphism (SNP) linkage disequilibrium (LD) map. SNP association was limited to the initial exons of a solitary gene of 3.6 kb (DPP10), which extends over 1 Mb of genomic DNA. DPP10 encodes a homolog of dipeptidyl peptidases (DPPs) that cleave terminal dipeptides from cytokines and chemokines, and it presents a potential new target for asthma therapy.

Demographic attributes of dispersing southern bog lemmings (Synaptomys cooperi) in eastern Kansas.

Demographic attributes of southern bog lemmings colonizing two removal grids were compared with those of residents on neighboring control grids over a two year period in eastern Kansas. There was a positive association between the number of lemmings colonizing the removal grids and density of the control grids. Overall, 41% of the losses from the two control grids was accounted for by dispersal. The following differences were observed comparing residents with dispersers: 1) a greater proportion of males colonized the removal grids, 2) a lower percentage of adult females colonizing the removal grids were in breeding condition, whereas the reverse was true for subadult females, and 3) a greater proportion of subadults colonized the removal grids. These results are consistent with those obtained for other microtine species."I don't understand", said the scientist, "why you lemmings all rush down to the sea and drown yourselves". "How curious", said the lemming. "The one thing I don't understand is why you human beings don't" - from Intervie with a Lemming by James Thurber.