Publications by authors named "Jeffrey Sommer"

Undernutrition limits reproduction through inhibition of gonadotropin-releasing hormone (GnRH)/luteinizing hormone (LH) secretion. Because KNDy neurons coexpress neuropeptides that play stimulatory (kisspeptin and neurokinin B [NKB]) and inhibitory (dynorphin) roles in pulsatile GnRH/LH release, we hypothesized that undernutrition would inhibit kisspeptin and NKB expression at the same time as increasing dynorphin expression. Fifteen ovariectomized lambs were either fed to maintain pre-study body weight (controls) or feed-restricted to lose 20% of pre-study body weight (FR) over 13 weeks.

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Puberty onset is a complex physiological process, which enables the capacity for reproduction through increased gonadotropin-releasing hormone and subsequently luteinizing hormone secretion. While cells that coexpress kisspeptin, neurokinin B (NKB), and dynorphin in the hypothalamic arcuate nucleus are believed to govern the timing of puberty, the degree to which kisspeptin/NKB/dynorphin (KNDy) neurons exist and are regulated by pubertal status remains to be determined in the gilt. Hypothalamic tissue from prepubertal and postpubertal, early follicular phase gilts was used to determine the expression of kisspeptin, NKB, and dynorphin within the arcuate nucleus.

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Agouti-related peptide (AgRP) neurons, which relay information from peripheral metabolic signals, may constitute a key central regulator of reproduction. Given that AgRP inhibits luteinizing hormone (LH) secretion and that nutritional suppression of LH elicits an increase in AgRP while suppressing kisspeptin expression in the arcuate nucleus (ARC) of the hypothalamus, we sought to examine the degree to which AgRP could directly regulate ARC kisspeptin neurons. Hypothalamic tissue was collected from four castrated male sheep (10 months of age) and processed for the detection of protein (AgRP input to kisspeptin neurons) using immunohistochemistry and mRNA for melanocortin 3 and 4 receptors (MC3R; MC4R) in kisspeptin neurons using RNAscope.

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Unlabelled: Undernutrition impairs reproductive success through suppression of gonadotropin-releasing hormone (GnRH), and subsequently luteinizing hormone (LH), secretion. Given that kisspeptin and neurokinin B (NKB) neurons in the arcuate nucleus (ARC) of the hypothalamus are thought to play key stimulatory roles in the generation of GnRH/LH pulses, we hypothesized that feed restriction would reduce the ARC mRNA abundance and protein expression of kisspeptin and NKB in young, male sheep. Fourteen wethers (castrated male sheep five months of age) were either fed to maintain (FM;  = 6) pre-study body weight or feed-restricted (FR;  = 8) to lose 20% of pre-study body weight over 13 weeks.

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Background: Like many species, pregnant swine mobilize and repartition body nutrient stores during extreme malnutrition to support fetal development.

Objective: The objective of this study was to model chronic human maternal malnutrition and measure effects of methylating-vitamins (MVs, containing choline, folate, B-6, B-12, and riboflavin) and docosahexaenoic acid (DHA) supplementation on fetal growth and development.

Methods: Pregnant gilts ( = 24) were either fully nourished (2.

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Background: Maternal nutrition has been highlighted as one of the main factors affecting intra-uterine environment. The increase in nutritional requirements by beef cows during late gestation can cause nutritional deficiency in the fetus and impact the fetal regulation of genes associated with myogenesis and immune response.

Methods: Forty days before the expected calving date, cows were assigned to one of two diets: 100% (control) or 70% (restricted group) of the daily energy requirement.

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Article Synopsis
  • - Expression of the
  • HMGA2
  • gene is linked to body size in both mice and humans, with gene alterations leading to significant reductions in size across species.
  • - Gene-edited HMGA2-deficient pigs demonstrated an average body weight decrease of 20%, with male pigs showing reductions of up to 85%, along with affected organ weights.
  • - The study confirms that HMGA2's role in growth regulation is conserved in mammals and suggests potential applications in managing body and organ size in various species, including those relevant to agriculture and pet care.
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Objective: 1) further define the time course required for transcription initiation in bovine cumulus-oocyte-complexes (COC); 2) determine the pattern of expression for Nr4A1 and Egr1 mRNAs in bovine COC; and, 3) reduce Nr4A1 mRNA expression using small interfering RNAs (siRNA) to determine the effect on breakdown of the germinal vesicle (GVBD).

Methods: A series of experiments were performed to define the time required for transcription initiation during FSH-induced maturation in bovine COCs, determine the pattern of expression for candidate mRNAs during GVBD, and use RNAi to determine their potential role in GVBD by examining whether candidate-specific siRNA can reduce mRNA expression in bovine COCs and affect the occurrence of GVBD.

Results: Transcription required for GVBD in bovine COC occurred as early as 30 min after culture initiation.

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Purpose: Autosomal dominant early-onset long anterior zonules (LAZs) and late-onset retinal degeneration (L-ORD) in humans are associated with the S163R mutation of the complement 1q-tumor necrosis factor related protein-5 (CTRP5) gene. For using the pig as an L-ORD model for the study of pathology, we cloned, characterized, and studied the expression profile of pig CTRP5 (pCTRP5).

Methods: The pCTRP5 was cloned and sequenced from porcine genomic DNA.

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Background: Truncation mutations in the elongation of very long chain fatty acids-4 (AF277094, MIM #605512) (ELOVL4) gene cause Stargardt-like macular dystrophy type 3 (STGD3). Mice expressing truncated ELOVL4 develop rapid retinal degeneration, but are poor STGD3 models since mice lack a macula. Photoreceptor topography in the pig retina is more similar to that in humans as it includes the cone rich, macula-like area centralis.

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The male germ line in mammals is composed of self-renewing cells, spermatogonia, the meiotic spermatocytes and spermiogenic spermatids. Identification of these cell stages in vitro has been problematic. Transgenic animals expressing a marker gene with a promoter specific to certain cell stages in the testis would be a useful approach to identifying these cells in a viable state.

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Rhodopsin (Pro347Leu) transgenic pigs are recognized to be an excellent model for the human disease, retinitis pigmentosa. First published in 1997, the rhodopsin transgenic pigs have been maintained since that time at North Carolina State University by outcrossing hemizygous boars to unrelated sows. Nine generations of outcrossing have been completed.

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Purpose: The Complement-1q tumor necrosis factor-related protein 5 (C1QTNF5/CTRP5) gene is located in the 3' untranslated region of the Membrane Frizzled Related Protein (MFRP) gene, and these two genes are reported to be dicistronic. The authors examined the 5' upstream sequence of CTRP5 for the presence of a promoter regulating the expression of this gene.

Methods: The sequence upstream of the translational start site of human CTRP5 (hCTRP5) was analyzed by Promoter Inspector software.

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While somatic cell nuclear transfer (SCNT) has been successful in several species, many pregnancies are lost and anomalies are found in fetal and perinatal stages. In this study SCNT and artificial inseminations (AI) populations were compared for litter size, average birth weight, piglets alive at birth, stillborn, mummies, dead at the first week, intrauterine growth restriction (IUGR) and large for gestational age (LGA). Twenty-three SCNT litters (143 individuals) were compared to 112 AI litters (1300 individuals).

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This study measured aerosol emission rates produced during the spreading of dewatered class B biosolids onto agricultural land. Rates were determined in multiple independent experimental runs by characterizing both the source aerosol plume geometry and aerosol concentrations of PM10, total bacteria, heterotrophic plate count bacteria (HPC), two types of biosolids indicator bacteria, endotoxin, and airborne biosolids regulated metals. These components were also measured in the bulk biosolids to allow for correlating bulk biosolids concentrations with aerosol emission rates and to produce reconstructed aerosol concentrations.

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An efficient protocol was developed to synchronize and superovulate mature pigs for the collection of pronuclear stage embryos suitable for DNA microinjection. A timed and coordinated regimen of Lutalyse, PG600 and Chorulon along with daily checking for estrus allowed synchronization of groups of gilts having estrous cycles at regular intervals. Pigs 10-16 days after the beginning of standing estrus have been successfully synchronized into estrus using this protocol.

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We have devised a system for the study of in vivo gene correction based on the detection of color variants of the green fluorescent protein (GFP) from the jellyfish Aequorea victoria. The intensity and spectra of the fluorescence emitted by the blue (BFP) and red-shifted (EGFP) variants of GFP differ from each other. We modified one nucleotide from an EGFP expression vector that we predicted would yield a blue variant (TAC-CAC, Tyr(66)-His(66)).

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Follicle-stimulating hormone controls the maturation of mammalian ovarian follicles. In excess, it can increase ovulation (egg production). Reported here is a transgenic doxycycline-activated switch, tested in mice, that produced more FSHB subunit (therefore more FSH) and increased ovulation by the simple feeding of doxycycline (Dox).

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