A putative pheromone receptor gene is expressed in two distinct olfactory organs in goats

Mammals possess two anatomically and functionally distinct olfactory systems. The olfactory epithelium (OE) detects volatile odorants, while the vomeronasal organ (VNO) detects pheromones that elicit innate reproductive and social behavior within a species. In rodent VNO, three multigene families that encode the putative pheromone receptors, V1Rs, V2Rs and V3Rs, have been expressed. We have identified the V1R homologue genes from goat genomic DNA (gV1R genes). Deduced amino acid sequences of gV1R genes show 40-50% and 20-25% identity to those of rat and mouse V1R and V3R genes, respectively, suggesting that the newly isolated goat receptor genes are members of the V1R gene family. One gene (gV1R1 gene) has an open reading frame that encodes a polypeptide of 309 amino acids. It is expressed not only in VNO but also in OE. In situ hybridization analysis revealed that gV1R1 -expressing cells were localized in neuropithelial layers of VNO and OE. These results suggest that the goat may detect pheromone molecules through two distinct olfactory organs.     

Impact of Exercise and Moderate Hypoxia on Glycemic Regulation and Substrate Oxidation Pattern

Objective

We examined metabolic and endocrine responses during rest and exercise in moderate hypoxia over a 7.5 h time courses during daytime.

Methods

Eight sedentary, overweight men (28.6±0.8 kg/m²) completed four experimental trials: a rest trial in normoxia (FiO₂ = 20.9%, NOR-Rest), an exercise trial in normoxia (NOR-Ex), a rest trial in hypoxia (FiO₂ = 15.0%, HYP-Rest), and an exercise trial in hypoxia (HYP-Ex). Experimental trials were performed from 8:00 to 15:30 in an environmental chamber. Blood and respiratory gas samples were collected over 7.5 h. In the exercise trials, subjects performed 30 min of pedaling exercise at 60% of VO₂max at 8:00, 10:30, and 13:00, and rested during the remaining period in each environment. Standard meals were provided at 8:30, 11:00, and 13:30.

Results

The areas under the curves for blood glucose and serum insulin concentrations over 7.5 h did not differ among the four trials. At baseline, %carbohydrate contribution was significantly higher in the hypoxic trials than in the normoxic trials (P<0.05). Although exercise promoted carbohydrate oxidation in the NOR-Ex and HYP-Ex trials, %carbohydrate contribution during each exercise and post-exercise period were significantly higher in the HYP-Ex trial than in the NOR-Ex trial (P<0.05).

Conclusion

Three sessions of 30 min exercise (60% of VO₂max) in moderate hypoxia over 7.5 h did not attenuate postprandial glucose and insulin responses in young, overweight men. However, carbohydrate oxidation was significantly enhanced when the exercise was conducted in moderate hypoxia.     

Induced activity of adenine phosphoribosyltransferase (APRT) in iron-deficiency barley roots: a possible role for phytosiderophore production

To isolate the genes involved in the response of graminaceous plants to Fe-deficient stress, a protein induced by Fe-deficiency treatment was isolated from barley (Hordeum vulgare L.) roots. Based on the partial amino acid sequence of this protein, a cDNA (HvAPT1) encoding adenine phosphoribosyltransferase (APRT: EC 2.4.2.7) was cloned from a cDNA library prepared from Fe-deficient barley roots. Southern analysis suggested that there were at least two genes encoding APRT in barley. Fe deficiency increased HvAPT1 expression in barley roots and resupplying Fe to the Fe-deficient plants rapidly negated the increase in HvAPT1 mRNA. Analysis of localization of HvAPT1-sGFP fusion proteins in tobacco BY-2 cells indicated that the protein from HvAPT1 was localized in the cytoplasm of cells. Consistent with the results of Northern analysis, the enzymatic activity of APRT in barley roots was remarkably increased by Fe deficiency. This induction of APRT activity by Fe deficiency was also observed in roots of other graminaceous plants such as rye, maize, and rice. In contrast, the induction was not observed to occur in the roots of a non-graminaceous plant, tobacco. Graminaceous plants generally synthesize the mugineic acid family phytosiderophores (MAs) in roots under Fe-deficient conditions. In this paper, a possible role of HvAPT1 in the biosynthesis of MAs related to adenine salvage in the methionine cycle is discussed.     

A new species of Trichogramma (Hymenoptera: Trichogrammatidae) parasitic on eggs of the alderfly Sialis melania (Neuroptera: Sialidae) from Japan,with comments on its phylogeny and male wing polymorphism

A new species of Trichogramma that parasitizes Sialis melania eggs is described as Trichogramma tajimaense Yashiro, Hirose and Honda, sp. nov. from Japan. Its phylogenetic position is based on a DNA‐based analysis, and data regarding its male wing polymorphism are also presented. The view that T. tajimaense is closely related to T. semblidis, another parasitoid of Sialis eggs, is supported by the results of a phylogenetic analysis, as well as by the biological and morphological similarities between both species. Trichogramma tajimaense is also similar in male wing polymorphism to T. kurosuae, a gregarious egg parasitoid of the lepidopteran Ivela auripes, as both Trichogramma species exhibit male wing trimorphism (fully alate, brachypterous and apterous forms) in contrast to the male wing dimorphism (fully alate and apterous forms) of T. semblidis. However, no phylogenetic analysis reveals a close relationship between T. tajimaense and T. kurosuae, and a difference exists between these two species in the mean percentage of flightless (brachypterous and apterous) males that emerge from a host egg mass; 96% of T. tajimaense males are incapable of flight, whereas about 50% of T. kurosuae males are flightless. Because all or almost all males of T. semblidis parasitizing Sialis eggs are apterous, T. tajimaense is more similar to T. semblidis than to T. kurosuae in the proportion of flightless males. In addition, male wing polymorphisms of Trichogramma in relation to mating systems could also show a similarity between T. tajimaense and T. semblidis when considering both species as quasi‐gregarious parasitoids of Sialis eggs.     

Dimerization of DOCK2 Is Essential for DOCK2-Mediated Rac Activation and Lymphocyte Migration

The migratory properties of lymphocytes depend on DOCK2, an atypical Rac activator predominantly expressed in hematopoietic cells. Although DOCK2 does not contain the Dbl homology domain typically found in guanine nucleotide exchange factors (GEFs), DOCK2 mediates the GTP-GDP exchange reaction for Rac via its DOCK homology region (DHR)-2 (also known as CZH2 or Docker) domain. DOCK2 DHR-2 domain is composed of three lobes, and Rac binding site and catalytic center are generated entirely from lobes B and C. On the other hand, lobe A has been implicated in dimer formation, yet its physiological significance remains unknown. Here, we report that lobe A-mediated DOCK2 dimerization is crucial for Rac activation and lymphocyte migration. We found that unlike wild-type DOCK2, DOCK2 mutant lacking lobe A failed to restore motility and polarity when expressed in thymoma cells and primary T cells lacking endogenous expression of DOCK2. Similar results were obtained with the DOCK2 point mutant having a defect in dimerization. Deletion of lobe A from the DHR-2 domain did not affect Rac GEF activity in vitro. However, fluorescence resonance energy transfer analyses revealed that lobe A is required for DOCK2 to activate Rac effectively during cell migration. Our results thus indicate that DOCK2 dimerization is functionally important under the physiological condition where only limited amounts of DOCK2 and Rac are localized to the plasma membrane.     

Lipocalin 2 diminishes invasiveness and metastasis of Ras-transformed cells

Lipocalin 2, an iron-siderophore-binding protein, converts embryonic kidney mesenchyme to epithelia. We found that lipocalin 2 could also convert 4T1-Ras-transformed mesenchymal tumor cells to an epithelial phenotype, increase E-cadherin expression, and suppress cell invasiveness in vitro and tumor growth and lung metastases in vivo. The Ras-MAPK pathway mediated the epithelial to mesenchymal transition in part by increasing E-cadherin phosphorylation and degradation. Lipocalin 2 antagonized these effects at a point upstream of Raf activation. Lipocalin 2 action was enhanced by iron-siderophore. These data characterize lipocalin 2 as an epithelial inducer in Ras malignancy and a suppressor of metastasis.     

Correction to: Comparative analysis of sperm motility in liquid and seminal coagulum portions between Bornean orangutan (Pongo pygmaeus) and chimpanzee (Pan troglodytes)

Primates - In the original publication of the article, the coauthor “Takashi Hayakawa” was wrongly assigned as co-corresponding author.     

Role of cumulus cells during maturation of porcine oocytes in the rise in intracellular Ca2+ induced by inositol 1,4,5-trisphosphate

At the time of fertilization, release of inositol 1,4,5-trisphosphate (IP3) into the cytoplasm of oocytes is said to be induced by hydrolysis of phosphatidylinositol bis phosphate (PI2) via activation of phospholipase C and is responsible for the Ca2+ oscillation in oocytes immediately after sperm penetration. On the other hand, cumulus cells have been reported to play an important role in cytoplasmic maturation of mammalian oocytes and to affect embryonic development after fertilization. To obtain more information on the role of cumulus cells in cytoplasmic maturation of oocytes, the effects of cumulus cells on the rise in [Ca2+]i and the rates of activation and development of porcine mature oocytes induced by IP3 injection were investigated. Mature porcine oocytes that had been denuded of their cumulus cells in the early stage of the maturation period had a depressed rise in [Ca2+]i (4.0-6.0) and reduced rates of activation (31.4-36.8%) and development (10.0-24.4%) induced by IP3 injection compared with those of their cumulus-enclosed counterparts (7.3, 69.1% and 43.8%; P < 0.05). The [Ca2+]i rise and the rates of activation and development depressed by the removal of cumulus cells were restored by adding pyruvate to the maturation medium. Furthermore, the IP3 injection-induced depression of [Ca2+]i rise in mature oocytes derived from cumulus-denuded oocytes (DOs) was restored when they were cultured in a medium with pyruvate (3.9-6.3, P < 0.05). Also, mature oocytes from cumulus-oocyte complexes (COCs) cultured in a medium without glucose had a lower rise in [Ca2+]i than that in mature oocytes from COCs cultured with glucose (7.4-6.0, P < 0.05). Cumulus cells supported porcine oocytes during maturation in the rise in [Ca2+]i induced by IP3 and the following activation and development of porcine oocytes after injection of IP3. Moreover, we inferred that a function of cumulus cells is to produce pyruvate by metabolizing glucose and to provide oocytes with pyruvate during maturation, thereby promoting oocyte sensitivity to IP3.