792 research outputs found
The Microbiota and Health Promoting Characteristics of the Fermented Beverage Kefir
peer-reviewedKefir is a complex fermented dairy product created through the symbiotic fermentation of milk by lactic acid bacteria and yeasts contained within an exopolysaccharide and protein complex called a kefir grain. As with other fermented dairy products, kefir has been associated with a range of health benefits such as cholesterol metabolism and angiotensin-converting enzyme (ACE) inhibition, antimicrobial activity, tumor suppression, increased speed of wound healing, and modulation of the immune system including the alleviation of allergy and asthma. These reports have led to increased interest in kefir as a focus of research and as a potential probiotic-containing product. Here, we review those studies with a particular emphasis on the microbial composition and the health benefits of the product, as well as discussing the further development of kefir as an important probiotic product.The authors are funded through the Teagasc Walsh Fellowship Scheme(2014025)and internal Teagasc funding(RMIS6486). BW is supported by the Canada Research Chairs Program and research in the Cotter laboratory is funded by SFI through the PI award âObesibioticsâ(11/PI/1137)and in the form of a center grant (APC Microbiome Institute Grant Number SFI/12/RC/2273)
Mutations in sphingosine-1-phosphate lyase cause nephrosis with ichthyosis and adrenal insufficiency
Loss-of-function mutations in UDP-Glucose 6-Dehydrogenase cause recessive developmental epileptic encephalopathy
Cross-linking of Nitrogenase Components: Structure and Activity of the Covalent Complex
The nitrogenase complex from Azotobacter vinelandii is composed of the MoFe protein (Av1), an α_2ÎČ_2 tetramer, and the Fe protein (Av2), a Îł_2 dimer. During turnover of the enzyme, electrons are transferred from Av2 to Av1 in parallel with the hydrolysis of MgATP. Using the cross-linking reagent, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, we have identified some of the properties of the complex between the two components. The cross-linking reaction was highly specific yielding a single apparent M_r = 97,000 protein. The amount of cross-linked product was essentially independent of whether MgATP or MgADP were in the reaction. Also, the amount was maximum at high ratios of Av2 to Av1. The M_r = 97,000 protein was characterized by amino acid analysis and Edman degradation and was found to be consistent with a 1:1 complex of an Av2 Îł subunit and an Av1 ÎČ subunit (the amino terminal serine subunit). The complex was no longer active in the nitrogenase reaction which supports, but does not prove, the requirement for dissociation of the complex after each electron transferred. Nitrogenase activity and cross-linking were inhibited in an identical way by NaCl, which suggests that electrostatic forces are critical to the formation of the electron transfer complex
Genome-wide sequence information reveals recurrent hybridization among diploid wheat wild relatives
General Strategies for Isolating the Genes Encoding Type I Collagen and for Characterizing Mutations Which Produce Osteogenesis Imperfecta a
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73326/1/j.1749-6632.1988.tb55325.x.pd
Skateboarding in the Anthropocene: Grey spaces of polluted leisure
This is the final version. Available from Routledge via the DOI in this record.âŻThis paper explores a symbolic environmental schema of skateboarding
through the concept of âgrey spacesâ. We provide evidence of how skateboarding demonstrates a greyness â political and environmental ambiguities, contradictions, liminality, nuances and paradoxes â to outdoor
urban leisure in the Anthropocene. We build on a chromatic turn in leisure
studies which attends to blue and green spaces; however, we shift focus
from the therapeutic discussion of nature that tends to underscore that
turn to a contested realm of urban grey spaces. A concept of âgreynessâ is
adopted to connote not simply the urban but also the ambivalence of
polluted leisure and the ambiguous position of skateboarding working as
pollutant, and a form of alternative sustainability, while acting with complicity in neoliberal processes that contribute to escalating consumption
and the proliferation of concrete spaces of play. In framing skateboarding
in both the material and symbolic space of greyness, we seek to stimulate
discussion about the greyness of leisure in the Anthropocene beyond
skateboarding
Cryptic MHC Polymorphism Revealed but Not Explained by Selection on the Class IIB Peptide-Binding Region
The immune genes of the major histocompatibility complex (MHC) are characterized by extraordinarily high levels of nucleotide and haplotype diversity. This variation is maintained by pathogen-mediated balancing selection that is operating on the peptide-binding region (PBR). Several recent studies have found, however, that some populations possess large clusters of alleles that are translated into virtually identical proteins. Here, we address the question of how this nucleotide polymorphism is maintained with little or no functional variation for selection to operate on. We investigate circa 750â850 bp of MHC class II DAB genes in four wild populations of the guppy Poecilia reticulata. By sequencing an extended region, we uncovered 40.9% more sequences (alleles), which would have been missed if we had amplified the exon 2 alone. We found evidence of several gene conversion events that may have homogenized sequence variation. This reduces the visible copy number variation (CNV) and can result in a systematic underestimation of the CNV in studies of the MHC and perhaps other multigene families. We then focus on a single cluster, which comprises 27 (of a total of 66) sequences. These sequences are virtually identical and show no signal of selection. We use microsatellites to reconstruct the populations' demography and employ simulations to examine whether so many similar nucleotide sequences can be maintained in the populations. Simulations show that this variation does not behave neutrally. We propose that selection operates outside the PBR, for example, on linked immune genes or on the âsheltered loadâ that is thought to be associated to the MHC. Future studies on the MHC would benefit from extending the amplicon size to include polymorphisms outside the exon with the PBR. This may capture otherwise cryptic haplotype variation and CNV, and it may help detect other regions in the MHC that are under selection
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