Mucin gene (MUC 2 and MUC 5AC) upregulation by Gram-positive and Gram-negative bacteria

Bacterial infection of the lung is associated with mucin overproduction. In partial explanation of this phenomenon, we recently reported that supernatant from the Gram-negative organism Pseudomonas (P.) aeruginosa contained an activity that upregulated transcription of the MUC 2 mucin gene [J.-D. Li, A. Dohrman, M. Gallup, S. Miyata, J. Gum, Y. Kim, J. Nadel, A. Prince, C. Basbaum, Transcriptional activation of mucin by P. aeruginosa lipopolysaccharide in the pathogenesis of cystic fibrosis lung disease, Proc. Natl. Acad. Sci. U.S.A., 94 (1997) 967-972]. The purpose of the present study was to determine whether mucin genes other than MUC 2 are so regulated and whether Gram-positive organisms also contain mucin stimulatory activity. Results from in situ hybridization and RNase protection assays showed that P. aeruginosa upregulates MUC 5AC as well as MUC 2 in both bronchial explants and cultured airway epithelial cells. The upregulation of both genes by P. aeruginosa can be mimicked by lipopolysaccharide (LPS) and can be blocked by the tyrosine kinase inhibitor genistein. In addition, both genes are upregulated by a variety of Gram-positive as well as Gram-negative organisms showing the same rank order of potency. These data indicate the existence of a general mechanism by which epithelial cells respond to the presence of bacteria by increasing mucin synthesis.

Genetic recombination is targeted towards gene promoter regions in dogs

The identification of the H3K4 trimethylase, PRDM9, as the gene responsible for recombination hotspot localization has provided considerable insight into the mechanisms by which recombination is initiated in mammals. However, uniquely amongst mammals, canids appear to lack a functional version of PRDM9 and may therefore provide a model for understanding recombination that occurs in the absence of PRDM9, and thus how PRDM9 functions to shape the recombination landscape. We have constructed a fine-scale genetic map from patterns of linkage disequilibrium assessed using high-throughput sequence data from 51 free-ranging dogs, Canis lupus familiaris. While broad-scale properties of recombination appear similar to other mammalian species, our fine-scale estimates indicate that canine highly elevated recombination rates are observed in the vicinity of CpG rich regions including gene promoter regions, but show little association with H3K4 trimethylation marks identified in spermatocytes. By comparison to genomic data from the Andean fox, Lycalopex culpaeus, we show that biased gene conversion is a plausible mechanism by which the high CpG content of the dog genome could have occurred.

Recombination in mammalian genomes tends to occur within highly localized regions known as recombination hotspots. These hotspots appear to be a ubiquitous feature of mammalian genomes, but tend to not be shared between closely related species despite high levels of DNA sequence similarity. This disparity has been largely explained by the discovery of PRDM9 as the gene responsible for localizing recombination hotspots via recognition and binding to specific DNA motifs. Variation within PRDM9 can lead to changes to the recognized motif, and hence changes to the location of recombination hotspots thought the genome. Multiple studies have shown that PRDM9 is under strong selective pressure, apparently leading to a rapid turnover of hotspot locations between species. However, uniquely amongst mammals, PRDM9 appears to be dysfunctional in dogs and other canids. In this paper, we investigate how the loss of PRDM9 has affected the fine-scale recombination landscape in dogs and contrast this with patterns seen in other species.

RNA:DNA hybrids in the human genome have distinctive nucleotide characteristics, chromatin composition, and transcriptional relationships

Background

RNA:DNA hybrids represent a non-canonical nucleic acid structure that has been associated with a range of human diseases and potential transcriptional regulatory functions. Mapping of RNA:DNA hybrids in human cells reveals them to have a number of characteristics that give insights into their functions.

Results

We find RNA:DNA hybrids to occupy millions of base pairs in the human genome. A directional sequencing approach shows the RNA component of the RNA:DNA hybrid to be purine-rich, indicating a thermodynamic contribution to their in vivo stability. The RNA:DNA hybrids are enriched at loci with decreased DNA methylation and increased DNase hypersensitivity, and within larger domains with characteristics of heterochromatin formation, indicating potential transcriptional regulatory properties. Mass spectrometry studies of chromatin at RNA:DNA hybrids shows the presence of the ILF2 and ILF3 transcription factors, supporting a model of certain transcription factors binding preferentially to the RNA:DNA conformation.

Conclusions

Overall, there is little to indicate a dependence for RNA:DNA hybrids forming co-transcriptionally, with results from the ribosomal DNA repeat unit instead supporting the intriguing model of RNA generating these structures intrans. The results of the study indicate heterogeneous functions of these genomic elements and new insights into their formation and stability in vivo.

Electronic supplementary material

The online version of this article (doi:10.1186/s13072-015-0040-6) contains supplementary material, which is available to authorized users.

Attribution of mental States to others by schizophrenic patients

The purpose of this paper is to validate experimentally the hypothesis that postulates a distorted attribution of mental states to others in schizophrenics. Twelve subjects with a diagnosis of schizophrenia were compared with a normal and a clinical control group. Subjects were asked to read a comic strip (with no verbal material) and to choose one of the two answer cards which seemed the most logical to complete the sequence based on the supposed mental state of the character. The results of this study confirm the principal hypothesis that schizophrenics with thought and language disorders have an impaired ability to attribute intentions and false beliefs as they figure in this experiment. Although the theory of mind deficit was specific to schizophrenia for the attribution of false beliefs, no difference was found between the schizophrenic group and the depressed group for the attribution of intentions. Schizophrenics' choice is based specifically on a socially familiar experience rather than the context of the story.

Children with autism display more social behaviors after repeated imitation sessions

Based on earlier studies, an adult's imitations of the behaviors of children with autism lead to increased social behavior in the children. The present study explored the effects of repeated sessions of imitation. Twenty children were recruited from a school for children with autism to attend three sessions during which an adult either imitated all of the children's behaviors or simply played with the child. During the second session the children in the imitation group spent a greater proportion of time showing distal social behaviors toward the adult including: (1) looking; (2) vocalizing; (3) smiling; and (4) engaging in reciprocal play. During the third session, the children in the imitation group spent a greater proportion of time showing proximal social behaviors toward the adult including: (1) being close to the adult; (2) sitting next to the adult; and (3) touching the adult. These data suggest the potential usefulness of adult imitative behavior as an early intervention.

Facial responsiveness to odours in normal and pervasively developmentally disordered children

The facial responsiveness of 10 mutic children with pervasive developmental disorder (PDD) and 10 normal (N) children matched for sex and chronological age were covertly videotaped while presented with a set of odours contrasted in hedonic valence. Hedonic ratings of the stimuli were obtained both from the group of N subjects and a panel of adults. Two methods were used to measure facial responses in the same subjects. The first method consisted in an analysis of facial movements with the Facial Action Coding System. Results show that PDD and N subjects displayed distinct action units in response to unpleasant odours. PDD subjects typically displayed muscular actions indexing negative experience, while N subjects showed more smiles. With the second method, odour-elicited facial behaviour was rated by a panel of observers, who were asked to judge whether the subjects were exposed a pleasant, neutral or unpleasant smell. The facial responses to unpleasant odours were classified more accurately in PDD than in N subjects. These findings suggest a functional ability to sense the hedonics attached to odours, but a deficit of socialization of hedonic facial displays in developmentally disordered subjects.

Human respiratory mucus

Respiratory mucous glycoproteins may serve a number of protective functions for the airways; however, excessive secretions contribute to the morbidity of a variety of diseases including asthma, chronic bronchitis, and cystic fibrosis. Respiratory secretions are a mixture of cells, fluid, transudated and locally produced proteins, and mucous glycoproteins. The mucous glycoproteins give these secretions their characteristic viscosity and elasticity. While the physiologic control of mucous glycoprotein secretion is not completely understood, cholinergic, alpha-adrenergic, and beta-adrenergic stimuli may all contribute. Respiratory mucus hypersecretion seen in immediate hypersensitivity or inflammatory states may be due to reflex hypersecretion, to a variety of mediators (including histamine and cyclooxygenase or lipoxygenase pathway metabolites of arachidonic acid), or to substances released from phagocytic cells (such as macrophages, monocytes, or neutrophils). The limited number of specific approaches currently available for treating respiratory mucus hypersecretion include therapy of any underlying or intercurrent disease, improving clearance of secretions, and reducing mucus secretion with the use of glucocorticosteroids or anticholinergic drugs.

Screening and risk assessment for coronary artery disease in HIV infection: an unmet need

HIV infection is now considered a chronic, treatable disease, although treatment is associated with increased rates of coronary artery disease (CAD). Increased risk of CAD in HIV-infected patients has been associated with the inflammatory sequelae of the infection as well as the greater prevalence of cardiac risk factors in HIV-positive populations and the side effects of life-prolonging antiretroviral therapies. Patients with HIV infection now have a 1.5 to 2-fold greater risk of developing CAD compared with noninfected individuals, raising the independent risk of CAD in HIV infection to levels similar to those in diabetes. Despite this increased risk, screening and other adjuvant assessment tools are lacking. In this paper we explore the current climate of CAD in the contemporary HIV-infected population and look at the tools used in the assessment and management of patients as well as the limitations of these approaches for this at-risk population group.