Stem/progenitor cells and obstructive sleep apnea syndrome-new insights for clinical applications

Obstructive sleep apnea syndrome(OSAS) is a widespread disorder, characterized by recurrent upper airway obstruction during sleep, mostly as a result of complete or partial pharyngeal obstruction. Due to the occurrence of frequent and regular hypoxic events, patients with OSAS are at increased risk of cardiovascular disease, stroke, metabolic disorders, occupational errors, motor vehicle accidents and even death. Thus, OSAS has severe consequences and represents a significant economic burden. However, some of the consequences, as well as their costs can be reduced with appropriate detection and treatment. In this context, the recent advances that were made in stem cell biology knowledge and stem cell- based technologies hold a great promise for various medical conditions, including respiratory diseases. However, the investigation of the role of stem cells in OSAS is still recent and rather limited, requiring further studies, both in animal models and humans. The goal of this review is to summarize the current state of knowledge regarding both lung resident as well as circulating stem/progenitor cells and discuss existing controversies in the field in order to identify future research directions for clinical applications in OSAS. Also, the paper highlights the requisite for inter-institutional, multi-disciplinary research collaborations in order to achieve breakthrough results in the field.     

Microbial Transport, Survival, and Succession in a Sequence of Buried Sediments

Abstract Two chronosequences of unsaturated, buried loess sediments, ranging in age from <10,000 years to >1 million years, were investigated to reconstruct patterns of microbial ecological succession that have occurred since sediment burial. The relative importance of microbial transport and survival to succession was inferred from sediment ages, porewater ages, patterns of abundance (measured by direct counts, counts of culturable cells, and total phospholipid fatty acids), activities (measured by radiotracer and enzyme assays), and community composition (measured by phospholipid fatty acid patterns and Biolog substrate usage). Core samples were collected at two sites 40 km apart in the Palouse region of eastern Washington State, near the towns of Washtucna and Winona. The Washtucna site was flooded multiple times during the Pleistocene by glacial outburst floods; the Winona site elevation is above flood stage. Sediments at the Washtucna site were collected from near surface to 14.9 m depth, where the sediment age was approximately 250 ka and the porewater age was 3700 years; sample intervals at the Winona site ranged from near surface to 38 m (sediment age: approximately 1 Ma; porewater age: 1200 years). Microbial abundance and activities declined with depth at both sites; however, even the deepest, oldest sediments showed evidence of viable microorganisms. Same-age sediments had equal quantities of microorganisms, but different community types. Differences in community makeup between the two sites can be attributed to differences in groundwater recharge and paleoflooding. Estimates of the microbial community age can be constrained by porewater and sediment ages. In the shallower sediments (<9 m at Washtucna, <12 m at Winona), the microbial communities are likely similar in age to the groundwater; thus, microbial succession has been influenced by recent transport of microorganisms from the surface. In the deeper sediments, the populations may be considerably older than the porewater ages, since microbial transport is severely restricted in unsaturated sediments. This is particularly true at the Winona site, which was never flooded.     

The composition of the gut microbiota shapes the colon mucus barrier

Two C57BL/6 mice colonies maintained in two rooms of the same specific pathogen-free (SPF) facility were found to have different gut microbiota and a mucus phenotype that was specific for each colony. The thickness and growth of the colon mucus were similar in the two colonies. However, one colony had mucus that was impenetrable to bacteria or beads the size of bacteria—which is comparable to what we observed in free-living wild mice—whereas the other colony had an inner mucus layer penetrable to bacteria and beads. The different properties of the mucus depended on the microbiota, as they were transmissible by transfer of caecal microbiota to germ-free mice. Mice with an impenetrable mucus layer had increased amounts of Erysipelotrichi, whereas mice with a penetrable mucus layer had higher levels of Proteobacteria and TM7 bacteria in the distal colon mucus. Thus, our study shows that bacteria and their community structure affect mucus barrier properties in ways that can have implications for health and disease. It also highlights that genetically identical animals housed in the same facility can have rather distinct microbiotas and barrier structures.     

Cardiac mitochondria in heart failure: normal cardiolipin profile and increased threonine phosphorylation of complex IV

Mitochondrial dysfunction is a major contributor in heart failure (HF). We investigated whether the decrease in respirasome organization reported by us previously in cardiac mitochondria in HF is due to changes in the phospholipids of the mitochondrial inner membrane or modifications of the subunits of the electron transport chain (ETC) complexes. The contents of the main phospholipid species, including cardiolipin, as well as the molecular species of cardiolipin were unchanged in cardiac mitochondria in HF. Oxidized cardiolipin molecular species were not observed. In heart mitochondria isolated from HF, complex IV not incorporated into respirasomes exhibits increased threonine phosphorylation. Since HF is associated with increased adrenergic drive to cardiomyocytes, this increased protein phosphorylation might be explained by the involvement of cAMP-activated protein kinase. Does the preservation of cAMP-induced phosphorylation changes of mitochondrial proteins or the addition of exogenous cAMP have similar effects on oxidative phosphorylation? The usage of phosphatase inhibitors revealed a specific decrease in complex I-supported respiration with glutamate. In saponin-permeabilized cardiac fibers, pre-incubation with cAMP decreases oxidative phosphorylation due to a defect localized at complex IV of the ETC inter alia. We propose that phosphorylation of specific complex IV subunits decreases oxidative phosphorylation either by limiting the incorporation of complex IV in supercomplexes or by decreasing supercomplex stability.     

Identification and expression analysis of microRNAs and targets in the biofuel crop sugarcane

Background  

MicroRNAs (miRNAs) are small regulatory RNAs, some of which are conserved in diverse plant genomes. Therefore, computational identification and further experimental validation of miRNAs from non-model organisms is both feasible and instrumental for addressing miRNA-based gene regulation and evolution. Sugarcane (Saccharum spp.) is an important biofuel crop with publicly available expressed sequence tag and genomic survey sequence databases, but little is known about miRNAs and their targets in this highly polyploid species.     

Quantitative estimation of gibberellic acid by paper chromatography

Метод для количественного определения от gibberellic кислоты в процессе брожения средства массовой информации, с использованием бумаги по убыванию хроматографии в butylacetate воды описана. Образца корректируется, чтобы рН 2.5-3.0, добыто с н-бутанола, и 0,05 мл. органического слоя пятнами на Хроматографический бумагу. После equilibration от Атмосфера в банке, chromatogram Разработана в butylacetate насыщенных с водой, за 7 часов, и растворитель разрешено покинуть капельного нижней части листа. Обнаружение осуществляется путем опрыскивания с 3% раствор серной кислоты в метаноле и после сушки бумаги, пятна с синий u.v. флуоресценции наблюдается. Определенный артикль площадь пятна оценивается с помощью калибровочной кривой, заговор с ценностей, стандартов, соответствующих 20, 60 и 120 μ g. gibberellic кислоты. Погрешность оценки составляет ± 10-15% когда оценки выполняются тщательно. Низкий предел чувствительности 5 μg.     

Glioblastoma targeting via integrins is concentration dependent

A novel approach to treat cancer more selectively is achieved by targeting drugs to cells via conjugating the drug or imaging agent to an antibody or ligand for a cell surface receptor that is over‐expressed by the target cell population. Previous work by us has suggested that enhanced specificity can be obtained by multivalency of binding moieties. In this study we investigated the binding specificity of a multivalent construct including three peptides segments (TWYKIAFQRNRK), which bind the α₆β₁‐integrin, linked by poly(ethylene glycol) spacers. The binding specificity of the constructs was calculated by quantifying their binding to target cells (glioma cells, SF 767) relative to non‐targeted cells (normal human astrocytes, NHA). Dodecapeptide constructs (monovalent) exhibit specificity equal to the ratio of receptor expression at all concentrations. However, trivalent constructs demonstrated a sharp increase in specificity at concentrations less than the affinity of the receptor–ligand bond (4.28 µM). These experiments (conducted at 4°C) were consistent with the theoretical prediction and indicate that the biophysical model captures the basic trend of the data in the absence of receptor internalization, although the concentration at which increased specificity is observed is greater than predicted. The biophysical model does not predict the results of 37°C experiments, and this is shown to be due to internalization which occurs at 37°C but not at 4°C. Biotechnol. Bioeng. 2009; 104: 408–417 © 2009 Wiley Periodicals, Inc.     

Proteolytic cleavage of pertussis toxin S1 subunit is not essential for its activity in mammalian cells

Background  

Pertussis toxin (PT) is an exotoxin virulence factor produced by Bordetella pertussis, the causative agent of whooping cough. PT consists of an active subunit (S1) that ADP-ribosylates the alpha subunit of several mammalian G proteins, and a B oligomer (S2–S5) that binds glycoconjugate receptors on cells. PT appears to enter cells by endocytosis, and retrograde transport through the Golgi apparatus may be important for its cytotoxicity. A previous study demonstrated that proteolytic processing of S1 occurs after PT enters mammalian cells. We sought to determine whether this proteolytic processing of S1 is necessary for PT cytotoxicity.