55 research outputs found
Role of Luteinising Hormone in ovarian follicle development and maturation in the mare
Luteinising hormone (LH) is a crucial regulator of ovarian follicle maturation,
ovulation and luteinisation. Development of healthy follicles and fertile ovulation
can only occur within a specific range of circulating LH concentrations, with
differing upper and lower limits depending on the stage of the oestrous cycle. The
objective of the three studies in this thesis was to investigate the effects of both
physiological and non-physiological circulating LH levels on equine follicular
maturity by examining ovulatory and steroidogenic capacity, gene expression
profiles and miRNA expression in ovulatory-size follicles at various stages of the
oestrous cycle and/or in response to supplementation with LH.
The aim of the first study was to investigate the hypothesis that deficient circulating
LH is a primary cause for the inability of equine follicles to ovulate during the
physiological anovulatory season. A LH-rich equine pituitary fraction (eLH) given
twice daily to early transitional mares did not restore steroidogenic capacity of the
ovulatory-size follicle or advance the onset of the natural breeding season; however,
it significantly stimulated follicular growth to a level similar to that occurring during
the normal oestrous cycle. The results demonstrated that a deficiency in LH is
critically involved in reduced follicle growth during the anovulatory season.
The second study examined the effects of elevated circulating LH levels early during
follicle development on follicle maturation and ovulatory ability in cycling mares,
with the hypothesis that excessive LH would disrupt ovulation and produce
haemorrhagic anovulatory follicles (HAFs). Treatment with eLH or a luteolytic dose
of prostaglandin F2α (to stimulate an increase in endogenous levels of LH) did not
have any effects on follicle growth or ovulation, but did impair follicular production
of androstenedione and insulin-like growth factor 1 (IGF1), suggesting a deleterious
effect of high LH on follicle and oocyte maturation.
The third study examined the expression of different follicular factors associated
with follicle maturation as well as microRNAs (miRNAs) in ovulatory-size follicles
naturally developing under different LH milieus (oestrus, dioestrus and spring
transitional period). Progesterone and IGF1 were significantly reduced in follicles
developing in a low LH environment (dioestrus and transition). All four miRNAs
measured, miR-378, miR-542, miR-202 and miR-21 were found at higher levels in
subordinate follicles than in preovulatory follicles during oestrus. In addition miR-
202 and miR-21 were significantly increased in transitional follicles relative to
oestrous follicles. The results of this study indicate that follicles developing during
both the spring transitional and dioestrous periods are developmentally immature and
suggested potential important roles of miRNAs in follicle maturation in the horse.
In summary, although LH is a key factor promoting follicular growth, it is by itself
not sufficient to restore steroidogenic activity in transitional follicles. Elevated LH
levels during follicle development do not disrupt ovulation, but induce changes in
follicular fluid factors related to follicle maturation and oocyte quality. Follicles
developing under different LH milieus show altered miRNA expression, suggesting
an important role of miRNAs in follicle maturation
Analysis of carbon substrates used by Listeria monocytogenes during growth in J774A.1 macrophages suggests a bipartite intracellular metabolism
Intracellular bacterial pathogens (IBPs) are dependent on various nutrients provided by the host cells. Different strategies may therefore be necessary to adapt the intracellular metabolism of IBPs to the host cells. The specific carbon sources, the catabolic pathways participating in their degradation, and the biosynthetic performances of IBPs are still poorly understood. In this report, we have exploited the technique of C-13-isotopologue profiling to further study the carbon metabolism of Listeria monocytogenes by using the EGDe wild-type strain and mutants (defective in the uptake and/or catabolism of various carbon compounds) replicating in J774A.1 macrophages. For this goal, the infected macrophages were cultivated in the presence of [1, 2-C-13(2)]glucose, [U-C-13(3)]glycerol, [U-C-13(3)]pyruvate, [U-C-13(3)]lactate, or a mix of [U-C-13]amino acids. GC/MS-based isotopologue profiling showed efficient utilization of amino acids, glucose 6-phosphate, glycerol, and (at a low extent) also of lactate but not of pyruvate by the IBPs. Most amino acids imported from the host cells were directly used for bacterial protein biosynthesis and hardly catabolized. However, Asp was de novo synthesized by the IBPs and not imported from the host cell. As expected, glycerol was catabolized via the ATP-generating lower part of the glycolytic pathway, but apparently not used for gluconeogenesis. The intermediates generated from glucose 6-phosphate in the upper part of the glycolytic pathway and the pentose phosphate shunt likely serve primarily for anabolic purposes (probably for the biosynthesis of cell wall components and nucleotides). This bipartite bacterial metabolism which involves at least two major carbon substrates-glycerol mainly for energy supply and glucose 6-phosphate mainly for indispensible anabolic performances-may put less nutritional stress on the infected host cells, thereby extending the lifespan of the host cells to the benefit of the IBPs
Plutonium release from Fukushima Daiichi fosters the need for more detailed investigations
The contamination of Japan after the Fukushima accident has been investigated mainly for volatile fission products, but only sparsely for actinides such as plutonium. Only small releases of actinides were estimated in Fukushima. Plutonium is still omnipresent in the environment from previous atmospheric nuclear weapons tests. We investigated soil and plants sampled at different hot spots in Japan, searching for reactor-borne plutonium using its isotopic ratio Pu-240/Pu-239. By using accelerator mass spectrometry, we clearly demonstrated the release of Pu from the Fukushima Daiichi power plant: While most samples contained only the radionuclide signature of fallout plutonium, there is at least one vegetation sample whose isotope ratio (0.381 +/- 0.046) evidences that the Pu originates from a nuclear reactor (Pu239+240 activity concentration 0.49 Bq/kg). Plutonium content and isotope ratios differ considerably even for very close sampling locations, e.g. the soil and the plants growing on it. This strong localization indicates a particulate Pu release, which is of high radiological risk if incorporated.CDC NIOSH Mountain and Plains Education and Research Center/T42OH009229-07NRC/NRC-HQ-12-G-38-0044CDC NIOSH Mountain and Plains Education and Research Center/T42OH009229-07NRC/NRC-HQ-12-G-38-004
Evidence for L1-associated DNA rearrangements and negligible L1 retrotransposition in glioblastoma multiforme
Background: LINE-1 (L1) retrotransposons are a notable endogenous source of mutagenesis in mammals. Notably, cancer cells can support unusual L1 retrotransposition and L1-associated sequence rearrangement mechanisms following DNA damage. Recent reports suggest that L1 is mobile in epithelial tumours and neural cells but, paradoxically, not in brain cancers. Results: Here, using retrotransposon capture sequencing (RC-seq), we surveyed L1 mutations in 14 tumours classified as glioblastoma multiforme (GBM) or as a lower grade glioma. In four GBM tumours, we characterised one probable endonuclease-independent L1 insertion, two L1-associated rearrangements and one likely Alu-Alu recombination event adjacent to an L1. These mutations included PCR validated intronic events in MeCP2 and EGFR. Despite sequencing L1 integration sites at up to 250Ă depth by RC-seq, we found no tumour-specific, endonuclease-dependent L1 insertions. Whole genome sequencing analysis of the tumours carrying the MeCP2 and EGFR L1 mutations also revealed no endonuclease-dependent L1 insertions. In a complementary in vitro assay, wild-type and endonuclease mutant L1 reporter constructs each mobilised very inefficiently in four cultured GBM cell lines. Conclusions: These experiments altogether highlight the consistent absence of canonical L1 retrotransposition in GBM tumours and cultured cell lines, as well as atypical L1-associated sequence rearrangements following DNA damage in vivo
Barriers and opportunities for implementation of a brief psychological intervention for post-ICU mental distress in the primary care setting â results from a qualitative sub-study of the PICTURE trial
The GEOTRACES Intermediate Data Product 2014
The GEOTRACES Intermediate Data Product 2014 (IDP2014) is the first publicly available data product of the international GEOTRACES programme, and contains data measured and quality controlled before the end of 2013. It consists of two parts: (1) a compilation of digital data for more than 200 trace elements and isotopes (TEIs) as well as classical hydrographic parameters, and (2) the eGEOTRACES Electronic Atlas providing a strongly inter-linked on-line atlas including more than 300 section plots and 90 animated 3D scenes. The IDP2014 covers the Atlantic, Arctic, and Indian oceans, exhibiting highest data density in the Atlantic. The TEI data in the IDP2014 are quality controlled by careful assessment of intercalibration results and multi-laboratory data comparisons at cross-over stations. The digital data are provided in several formats, including ASCII spreadsheet, Excel spreadsheet, netCDF, and Ocean Data View collection. In addition to the actual data values the IDP2014 also contains data quality flags and 1-? data error values where available. Quality flags and error values are useful for data filtering. Metadata about data originators, analytical methods and original publications related to the data are linked to the data in an easily accessible way. The eGEOTRACES Electronic Atlas is the visual representation of the IDP2014 data providing section plots and a new kind of animated 3D scenes. The basin-wide 3D scenes allow for viewing of data from many cruises at the same time, thereby providing quick overviews of large-scale tracer distributions. In addition, the 3D scenes provide geographical and bathymetric context that is crucial for the interpretation and assessment of observed tracer plumes, as well as for making inferences about controlling processes
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Precise interpolar phasing of abrupt climate change during the last ice age
The last glacial period exhibited abrupt DansgaardâOeschger climatic oscillations, evidence of which is preserved in a variety of Northern Hemisphere palaeoclimate archivesÂč. Ice cores show that Antarctica cooled during the warm phases of the Greenland DansgaardâOeschger cycle and vice versa[superscript 2,3], suggesting an interhemispheric redistribution of heat through a mechanism called the bipolar seesaw[superscript 4â6]. Variations in the Atlantic meridional overturning circulation (AMOC) strength are thought to have been important, but much uncertainty remains regarding the dynamics and trigger of these abrupt events[superscript 7â9]. Key information is contained in the relative phasing of hemispheric climate variations, yet the large, poorly constrained difference between gas age and ice age and the relatively low resolution of methane records from Antarctic ice cores have so far precluded methane-based synchronization at the required sub-centennial precision[superscript 2,3,10]. Here we use a recently drilled high-accumulation Antarctic ice core to show that, on average, abrupt Greenland warming leads the corresponding Antarctic cooling onset by 218 ± 92 years (2Ï) for DansgaardâOeschger events, including the BĂžlling event; Greenland cooling leads the corresponding onset of Antarctic warming by 208 ± 96 years. Our results demonstrate a north-to-south directionality of the abrupt climatic signal, which is propagated to the Southern Hemisphere high latitudes by oceanic rather than atmospheric processes. The similar interpolar phasing of warming and cooling transitions suggests that the transfer time of the climatic signal is independent of the AMOC background state. Our findings confirm a central role for ocean circulation in the bipolar seesaw and provide clear criteria for assessing hypotheses and model simulations of DansgaardâOeschger dynamics
Screening the University of Wisconsin--Eau Claire Campus for Methicillin-Resistant Staphylococcus spp. Isolates Capable of Transferring Methicillin-Resistance
Color poster with text, images, photographs, and tables.The purpose of this study was to determine the presence of Methicillin-Resistant Staphylococcus on the University of Wisconsin-Eau Claire campus.University of Wisconsin--Eau Claire Office of Research and Sponsored Program
Jenaer Splitter III: Mittwoch - Bericht von der Abschlusskonferenz der DFG-Kollegforscher*innengruppe "Postwachstumsgesellschaften" und der 2. Regionalkonferenz der Deutschen Gesellschaft fĂŒr Soziologie in Jena
Nutritional and Seed Responses of Forage Kochia to Ruminal Incubation
Forage kochia may be a complimentary forage to most dormant cool-season grasses in the Intermountain West.The Rangelands archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform March 202
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