Endometrial Exosomes/Microvesicles in the Uterine Microenvironment: A New Paradigm for Embryo-Endometrial Cross Talk at Implantation

Exosomes are nanoparticles (∼100 nm diameter) released from cells, which can transfer small RNAs and mRNA via the extracellular environment to cells at distant sites. We hypothesised that exosomes or the slightly larger microvesicles (100–300 nm) are released from the endometrial epithelium into the uterine cavity, and that these contain specific micro (mi)RNA that could be transferred to either the trophectodermal cells of the blastocyst or to endometrial epithelial cells, to promote implantation. The aim of this study was to specifically identify and characterise exosomes/microvesicles (mv) released from endometrial epithelial cells and to determine whether exosomes/mv are present in uterine fluid. Immunostaining demonstrated that the tetraspanins, CD9 and CD63 used as cell surface markers of exosomes are present on the apical surfaces of endometrial epithelial cells in tissue sections taken across the menstrual cycle: CD63 showed cyclical regulation. Exosome/mv pellets were prepared from culture medium of endometrial epithelial cell (ECC1 cells) and from uterine fluid and its associated mucus by sequential ultracentifugation. Exosomes/mv were positively identified in all preparations by FACS and immunofluorescence staining following exosome binding to beads. Size particle analysis confirmed the predominance of particles of 50–150 nm in each of these fluids. MiRNA analysis of the ECC1 cells and their exosomes/mv demonstrated sorting of miRNA into exosomes/mv: 13 of the 227 miRNA were specific to exosomes/mv, while a further 5 were not present in these. The most abundant miRNA in exosomes/mv were hsa-miR-200c, hsa-miR-17 and hsa-miR-106a. Bioinformatic analysis showed that the exosome/mv-specific miRNAs have potential targets in biological pathways highly relevant for embryo implantation. Thus exosomes/mv containing specific miRNA are present in the microenvironment in which embryo implantation occurs and may contribute to the endometrial-embryo cross talk essential for this process.     

The Genus Gluconobacter Oxydans: Comprehensive Overview of Biochemistry and Biotechnological Applications

ABSTRACT

The genus Gluconobacter comprises some of the most frequently used microorganisms when it comes to biotechnological applications. Not only has it been involved in “historical” production processes, such as vinegar production, but in the last decades many bioconversion routes for special and rare sugars involving Gluconobacter have been developed. Among the most recent are the biotransformations involved in the production of L-ribose and miglitol, both very promising pharmaceutical lead molecules. Most of these processes make use of Gluconobacter's membrane-bound polyol dehydrogenases. However, recently other enzymes have also caught the eye of industrial biotechnology. Among them are dextran dextrinase, capable of transglucosylating substrate molecules, and intracellular NAD-dependent polyol dehydrogenases, of interest for co-enzyme regeneration. As such, Gluconobacter is an important industrial microbial strain, but it also finds use in other fields of biotechnology, such as biosensor-technology. This review aims to give an overview of the myriad of applications for Gluconobacter, with a special focus on some recent developments.     

Essential Role for Vacuolar Acidification in Candida albicans Virulence

Fungal infections are on the rise, with mortality above 30% in patients with septic Candida infections. Mutants lacking V-ATPase activity are avirulent and fail to acidify endomembrane compartments, exhibiting pleiotropic defects in secretory, endosomal, and vacuolar pathways. However, the individual contribution of organellar acidification to virulence and its associated traits is not known. To dissect their separate roles in Candida albicans pathogenicity we generated knock-out strains for the V₀ subunit a genes VPH1 and STV1, which target the vacuole and secretory pathway, respectively. While the two subunits were redundant in many vma phenotypes, such as alkaline pH sensitivity, calcium homeostasis, respiratory defects, and cell wall integrity, we observed a unique contribution of VPH1. Specifically, vph1Δ was defective in acidification of the vacuole and its dependent functions, such as metal ion sequestration as evidenced by hypersensitivity to Zn²⁺ toxicity, whereas stv1Δ resembled wild type. In growth conditions that elicit morphogenic switching, vph1Δ was defective in forming hyphae whereas stv1Δ was normal or only modestly impaired. Host cell interactions were evaluated in vitro using the Caco-2 model of intestinal epithelial cells, and murine macrophages. Like wild type, stv1Δ was able to inflict cellular damage in Caco-2 and macrophage cells, as assayed by LDH release, and escape by filamentation. In contrast, vph1Δ resembled a vma7Δ mutant, with significant attenuation in host cell damage. Finally, we show that VPH1 is required for fungal virulence in a murine model of systemic infection. Our results suggest that vacuolar acidification has an essential function in the ability of C. albicans to form hyphae and establish infection.     

A comparison of antemortem tooth loss in human hunter‐gatherers and non‐human catarrhines: Implications for the identification of behavioral evolution in the human fossil record

Middle and Late Pleistocene fossil hominin specimens with severe antemortem tooth loss are often regarded as evidence for the precocious evolution of human‐like behaviors, such as conspecific care or cooking, in ancient hominin species. The goal of this project was to ask whether the theoretical association between antemortem tooth loss and uniquely human behaviors is supported empirically in a large skeletal sample of human hunter‐gatherers, chimpanzees, orangutans, and baboons. Binomial regression modeling in a Bayesian framework allows for the investigation of the effects of tooth class, genus, age, and sex on the likelihood of tooth loss. The results strongly suggest that modern humans experience more antemortem tooth loss than non‐human primates and identify age in years as an important predictor. Once age is accounted for, the difference between the humans and the closest non‐human genus (chimpanzees) is less pronounced; humans are still more likely on average to experience antemortem tooth loss though 95% uncertainty envelopes around the average prediction for each genus show some overlap. These analyses support theoretical links between antemortem tooth loss and modern human characteristics; humans' significantly longer life history and a positive correlation between age and antemortem tooth loss explain, in part, the reason why humans are more likely to experience tooth loss than non‐human primates, but the results do not exclude behavioral differences as a contributing factor. Am J Phys Anthropol 151:252–264, 2013. © 2013 Wiley Periodicals, Inc.     

Synthesis and biological evaluation of prodigiosene conjugates of porphyrin,estrone and 4-hydroxytamoxifen

To generate the first series of prodigiosene conjugates, the tripyrrolic skeleton was appended to estrone, tamoxifen and porphyrin frameworks by way of ester linkers and various hydrocarbon chain lengths. The ability of the conjugates to inhibit various types of cancer cells was evaluated in vitro. The porphyrin conjugates did not exhibit significant activity. The estrone conjugates exhibited modest activity, for the most part. However, significantly greater growth inhibition activity against certain breast, colon, lung, leukemia, melanoma and prostate cell lines was noted. This unusual effect for this first generation model class of compound warrants further investigation and comparison to cases where estrogens are linked to prodigiosenes via connection points that do not feature in estrogen receptor binding. The 4-hydroxytamoxifen conjugates exhibit nanomolar range activity against the MCF-7 breast cancer cell line, paving the way to expand the scope and connectivity of prodigiosene–tamoxifen conjugates.     

Environmental Light Exposure Is Associated with Increased Body Mass in Children

The timing, intensity, and duration of exposure to both artificial and natural light have acute metabolic and physiological effects in mammals. Recent research in human adults suggests exposure to moderate intensity light later in the day is concurrently associated with increased body mass; however, no studies have investigated the effect of light exposure on body mass in young children. We examined objectively measured light exposure and body mass of 48 preschool-aged children at baseline, and measured their body mass again 12 months later. At baseline, moderate intensity light exposure earlier in the day was associated with increased body mass index (BMI). Increased duration of light exposure at baseline predicted increased BMI 12-months later, even after controlling for baseline sleep duration, sleep timing, BMI, and activity. The findings identify that light exposure may be a contributor to the obesogenic environment during early childhood.     

Does stream flow structure woody riparian vegetation in subtropical catchments?

The primary objective of this study was to test the relevance of hydrological classification and class differences to the characteristics of woody riparian vegetation in a subtropical landscape in Queensland, Australia. We followed classification procedures of the environmental flow framework ELOHA – Ecological Limits of Hydrologic Alteration. Riparian surveys at 44 sites distributed across five flow classes recorded 191 woody riparian species and 15, 500 individuals. There were differences among flow classes for riparian species richness, total abundance, and abundance of regenerating native trees and shrubs. There were also significant class differences in the occurrence of three common tree species, and 21 indicator species (mostly native taxa) further distinguished the vegetation characteristics of each flow class. We investigated the influence of key drivers of riparian vegetation structure (climate, depth to water table, stream‐specific power, substrate type, degree of hydrologic alteration, and land use) on riparian vegetation. Patterns were explained largely by climate, particularly annual rainfall and temperature. Strong covarying drivers (hydrology and climate) prevented us from isolating the independent influences of these drivers on riparian assemblage structure. The prevalence of species considered typically rheophytic in some flow classes implies a more substantial role for flow in these classes but needs further testing. No relationships were found between land use and riparian vegetation composition and structure. This study demonstrates the relevance of flow classification to the structure of riparian vegetation in a subtropical landscape, and the influence of covarying drivers on riparian patterns. Management of environmental flows to influence riparian vegetation assemblages would likely have most potential in sites dominated by rheophytic species where hydrological influences override other controls. In contrast, where vegetation assemblages are dominated by a diverse array of typical rainforest species, and other factors including broad‐scale climatic gradients and topographic variables have greater influence than hydrology, riparian vegetation is likely to be less responsive to environmental flow management.     

The distribution of the orange‐striped green anemone,Diadumene lineata,in relation to environmental factors along coastal British Columbia,Canada

The cosmopolitan nonindigenous sea anemone, Diadumene lineata, has been recorded from the Pacific coast of Canada since 1859. Despite its long historical presence in the region, the factors influencing the distribution of this species in British Columbia, Canada, are poorly understood, as are the factors that may restrict its local abundance. We conducted large‐scale surveys of D. lineata during the winter and summer of 2016, coupled with higher frequency surveys at one focal site. Furthermore, we used laboratory and field experiments to determine the potential importance of a large‐scale driver, salinity, and a small‐scale driver, microhabitat within boulders, in setting distributional limits at various spatial scales. Our results confirm that D. lineata is widely distributed within the Salish Sea. This broad distribution may be facilitated by post‐introduction dispersal; we observed anemones attached to floating substrata, and a few mature specimens contained eggs, suggesting that reproduction is perhaps not limited to asexual fission. We found that D. lineata was abundant throughout the year, although absent from the lowest salinity sites. This corresponded with our laboratory experiments, in which survival of individuals of D. lineata declined at salinities below 10 psu, and no survivors were observed at or below 2 psu. Manipulative experiments in the field demonstrated that survival was high under rocks where D. lineata is commonly found, but was reduced on the tops of rocks, highlighting the importance of microhabitat refugia in buffering temperature and reducing desiccation. A better understanding of the factors that limit the broad‐scale and local distribution of this anemone are an important step in determining potential ecological impacts of this organism and how distributions may shift into the future.     

Neuronal postdevelopmentally acting SAX-7S/L1CAM can function as cleaved fragments to maintain neuronal architecture in Caenorhabditis elegans

Whereas remarkable advances have uncovered mechanisms that drive nervous system assembly, the processes responsible for the lifelong maintenance of nervous system architecture remain poorly understood. Subsequent to its establishment during embryogenesis, neuronal architecture is maintained throughout life in the face of the animal’s growth, maturation processes, the addition of new neurons, body movements, and aging. The Caenorhabditis elegans protein SAX-7, homologous to the vertebrate L1 protein family of neural adhesion molecules, is required for maintaining the organization of neuronal ganglia and fascicles after their successful initial embryonic development. To dissect the function of sax-7 in neuronal maintenance, we generated a null allele and sax-7S-isoform-specific alleles. We find that the null sax-7(qv30) is, in some contexts, more severe than previously described mutant alleles and that the loss of sax-7S largely phenocopies the null, consistent with sax-7S being the key isoform in neuronal maintenance. Using a sfGFP::SAX-7S knock-in, we observe sax-7S to be predominantly expressed across the nervous system, from embryogenesis to adulthood. Yet, its role in maintaining neuronal organization is ensured by postdevelopmentally acting SAX-7S, as larval transgenic sax-7S(+) expression alone is sufficient to profoundly rescue the null mutants’ neuronal maintenance defects. Moreover, the majority of the protein SAX-7 appears to be cleaved, and we show that these cleaved SAX-7S fragments together, not individually, can fully support neuronal maintenance. These findings contribute to our understanding of the role of the conserved protein SAX-7/L1CAM in long-term neuronal maintenance and may help decipher processes that go awry in some neurodegenerative conditions.