167 research outputs found
The genetics of the Lp Antigen
Several genetic models were considered to explain the distribution of qualitatively positive and negative children in 204 Caucasian families. A model which best describes the inheritance of the Lp antigenic expression involves a major genetic locus which distinguishes two overlapping continuously distributed modes of quantitative activity.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66139/1/j.1469-1809.1974.tb01992.x.pd
Transverse spin effects in hadron-pair production from semi-inclusive deep inelastic scattering
First measurements of azimuthal asymmetries in hadron-pair production in
deep-inelastic scattering of muons on transversely polarised ^6LiD (deuteron)
and NH_3 (proton) targets are presented. The data were taken in the years
2002-2004 and 2007 with the COMPASS spectrometer using a muon beam of 160 GeV/c
at the CERN SPS. The asymmetries provide access to the transversity
distribution functions, without involving the Collins effect as in single
hadron production. The sizeable asymmetries measured on the NH_ target indicate
non-vanishing u-quark transversity and two-hadron interference fragmentation
functions. The small asymmetries measured on the ^6LiD target can be
interpreted as indication for a cancellation of u- and d-quark transversities.Comment: 13 pages, 4 figures, updated to the published versio
Impacts of climate change on plant diseases – opinions and trends
There has been a remarkable scientific output on the topic of how climate change is likely to affect plant diseases in the coming decades. This review addresses the need for review of this burgeoning literature by summarizing opinions of previous reviews and trends in recent studies on the impacts of climate change on plant health. Sudden Oak Death is used as an introductory case study: Californian forests could become even more susceptible to this emerging plant disease, if spring precipitations will be accompanied by warmer temperatures, although climate shifts may also affect the current synchronicity between host cambium activity and pathogen colonization rate. A summary of observed and predicted climate changes, as well as of direct effects of climate change on pathosystems, is provided. Prediction and management of climate change effects on plant health are complicated by indirect effects and the interactions with global change drivers. Uncertainty in models of plant disease development under climate change calls for a diversity of management strategies, from more participatory approaches to interdisciplinary science. Involvement of stakeholders and scientists from outside plant pathology shows the importance of trade-offs, for example in the land-sharing vs. sparing debate. Further research is needed on climate change and plant health in mountain, boreal, Mediterranean and tropical regions, with multiple climate change factors and scenarios (including our responses to it, e.g. the assisted migration of plants), in relation to endophytes, viruses and mycorrhiza, using long-term and large-scale datasets and considering various plant disease control methods
Measurement of the Collins and Sivers asymmetries on transversely polarised protons
The Collins and Sivers asymmetries for charged hadrons produced in deeply
inelastic scattering on transversely polarised protons have been extracted from
the data collected in 2007 with the CERN SPS muon beam tuned at 160 GeV/c. At
large values of the Bjorken x variable non-zero Collins asymmetries are
observed both for positive and negative hadrons while the Sivers asymmetry for
positive hadrons is slightly positive over almost all the measured x range.
These results nicely support the present theoretical interpretation of these
asymmetries, in terms of leading-twist quark distribution and fragmentation
functions.Comment: 9 Pages, 5 figure
CXCR6, a Newly Defined Biomarker of Tissue-Specific Stem Cell Asymmetric Self-Renewal, Identifies More Aggressive Human Melanoma Cancer Stem Cells
Background: A fundamental problem in cancer research is identifying the cell
type that is capable of sustaining neoplastic growth and its origin from normal
tissue cells. Recent investigations of a variety of tumor types have shown that
phenotypically identifiable and isolable subfractions of cells possess the
tumor-forming ability. In the present paper, using two lineage-related human
melanoma cell lines, primary melanoma line IGR39 and its metastatic derivative
line IGR37, two main observations are reported. The first one is the first
phenotypic evidence to support the origin of melanoma cancer stem cells (CSCs)
from mutated tissue-specific stem cells; and the second one is the
identification of a more aggressive subpopulation of CSCs in melanoma that are
CXCR6+. Conclusions/Significance: The association of a more aggressive tumor
phenotype with asymmetric self-renewal phenotype reveals a previously
unrecognized aspect of tumor cell physiology. Namely, the retention of some
tissue-specific stem cell attributes, like the ability to asymmetrically
self-renew, impacts the natural history of human tumor development. Knowledge
of this new aspect of tumor development and progression may provide new targets
for cancer prevention and treatment
Biology and biotechnology of Trichoderma
Fungi of the genus Trichoderma are soilborne, green-spored ascomycetes that can be found all over the world. They have been studied with respect to various characteristics and applications and are known as successful colonizers of their habitats, efficiently fighting their competitors. Once established, they launch their potent degradative machinery for decomposition of the often heterogeneous substrate at hand. Therefore, distribution and phylogeny, defense mechanisms, beneficial as well as deleterious interaction with hosts, enzyme production and secretion, sexual development, and response to environmental conditions such as nutrients and light have been studied in great detail with many species of this genus, thus rendering Trichoderma one of the best studied fungi with the genome of three species currently available. Efficient biocontrol strains of the genus are being developed as promising biological fungicides, and their weaponry for this function also includes secondary metabolites with potential applications as novel antibiotics. The cellulases produced by Trichoderma reesei, the biotechnological workhorse of the genus, are important industrial products, especially with respect to production of second generation biofuels from cellulosic waste. Genetic engineering not only led to significant improvements in industrial processes but also to intriguing insights into the biology of these fungi and is now complemented by the availability of a sexual cycle in T. reesei/Hypocrea jecorina, which significantly facilitates both industrial and basic research. This review aims to give a broad overview on the qualities and versatility of the best studied Trichoderma species and to highlight intriguing findings as well as promising applications
Ectopic T Cell Receptor-α Locus Control Region Activity in B Cells Is Suppressed by Direct Linkage to Two Flanking Genes at Once
The molecular mechanisms regulating the activity of the TCRα gene are required for the production of the circulating T cell repertoire. Elements of the mouse TCRα locus control region (LCR) play a role in these processes. We previously reported that TCRα LCR DNA supports a gene expression pattern that mimics proper thymus-stage, TCRα gene-like developmental regulation. It also produces transcription of linked reporter genes in peripheral T cells. However, TCRα LCR-driven transgenes display ectopic transcription in B cells in multiple reporter gene systems. The reasons for this important deviation from the normal TCRα gene regulation pattern are unclear. In its natural locus, two genes flank the TCRα LCR, TCRα (upstream) and Dad1 (downstream). We investigated the significance of this gene arrangement to TCRα LCR activity by examining transgenic mice bearing a construct where the LCR was flanked by two separate reporter genes. Surprisingly, the presence of a second, distinct, reporter gene downstream of the LCR virtually eliminated the ectopic B cell expression of the upstream reporter observed in earlier studies. Downstream reporter gene activity was unaffected by the presence of a second gene upstream of the LCR. Our findings indicate that a gene arrangement in which the TCRα LCR is flanked by two distinct transcription units helps to restrict its activity, selectively, on its 5′-flanking gene, the natural TCRα gene position with respect to the LCR. Consistent with these findings, a TCRα/Dad1 locus bacterial artificial chromosome dual-reporter construct did not display the ectopic upstream (TCRα) reporter expression in B cells previously reported for single TCRα transgenes
The Chemokine CXCL16 and Its Receptor, CXCR6, as Markers and Promoters of Inflammation-Associated Cancers
Clinical observations and mouse models have suggested that inflammation can be pro-tumorigenic. Since chemokines are critical in leukocyte trafficking, we hypothesized that chemokines play essential roles in inflammation-associated cancers. Screening for 37 chemokines in prostate cancer cell lines and xenografts revealed CXCL16, the ligand for the receptor CXCR6, as the most consistently expressed chemokine. Immunohistochemistry and/or immunofluorescence and confocal imaging of 121 human prostate specimens showed that CXCL16 and CXCR6 were co-expressed, both on prostate cancer cells and adjacent T cells. Expression levels of CXCL16 and CXCR6 on cancer cells correlated with poor prognostic features including high-stage and high-grade, and expression also correlated with post-inflammatory changes in the cancer stroma as revealed by loss of alpha-smooth muscle actin. Moreover, CXCL16 enhanced the growth of CXCR6-expressing cancer and primary CD4 T cells. We studied expression of CXCL16 in an additional 461 specimens covering 12 tumor types, and found that CXCL16 was expressed in multiple human cancers associated with inflammation. Our study is the first to describe the expression of CXCL16/CXCR6 on both cancer cells and adjacent T cells in humans, and to demonstrate correlations between CXCL16 and CXCR6 vs. poor both prognostic features and reactive changes in cancer stoma. Taken together, our data suggest that CXCL16 and CXCR6 may mark cancers arising in an inflammatory milieu and mediate pro-tumorigenic effects of inflammation through direct effects on cancer cell growth and by inducing the migration and proliferation of tumor-associated leukocytes
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