[Dissemination of Information from Basic Research on Aging: Species, Strain, Substrain and Sex Differences].

Various organisms with different lifespans such as yeast, nematodes, fruit fly, mice, and rats are used for basic research on mechanisms of aging and anti-aging. These organisms are often genetically engineered and used to elucidate the contribution of certain genes to aging. For example, genetic recombination techniques revealed that the lifespan of superoxide dismutase (SOD) transgenic flies extended up to approximately 30%. This result suggests that increasing antioxidant capacity extends lifespan possibly by reducing oxidative damage. However, a similar experiment conducted in mice did not shown any positive effect of prolonging lifespan. Likewise, differences between animal species have also been observed in administration experiments of antioxidants such as resveratrol and curcumin. Further complicating the understanding of aging processes are differences among substrain and sex differences. For instance, the activity of catalase (CAT) in rat liver decreases with age in males, but increases in females. In this review, we describe the diversity of age-related changes, focusing on species, strain/substrain, and sex differences and introduce some efforts to address these issues in aging research.

Genomic and phenotypic comparison of Prevotella intermedia strains possessing different virulence in vivo.

Prevotella intermedia readily colonizes healthy dental biofilm and is associated with periodontal diseases. The viscous exopolysaccharide (EPS)-producing capability is known as a major virulence factor of P. intermedia 17 (Pi17). However, the inter-strain difference in P. intermedia regarding virulence-associated phenotype is not well studied. We compared in vivo virulence and whole genome sequences using five wild-type strains: ATCC 49046 (Pi49046), ATCC 15032 (Pi15032), ATCC 15033 (Pi15033), ATCC 25611 (Pi25611), and Pi17. Non-EPS producing Pi25611 was the least virulent in insect and mammalian models. Unexpectedly, Pi49046 did not produce viscous EPS but was the most virulent, followed by Pi17. Genomes of the five strains were quite similar but revealed subtle differences such as copy number variations and single nucleotide polymorphisms. Variations between strains were found in genes encoding glycosyltransferases and genes involved in the acquisition of carbohydrates and iron/haem. Based on these genetic variations, further analyses were performed. Phylogenetic and structural analyses discovered phosphoglycosyltransferases of Pi49046 and Pi17 have evolved to contain additional loops that may confer substrate specificity. Pi17, Pi15032, and Pi15033 displayed increased growth by various carbohydrates. Meanwhile, Pi49046 exhibited the highest activities for haemolysis and haem accumulation, as well as co-aggregation with Porphyromonas gingivalis harbouring fimA type II, which is more tied to periodontitis than other fimA types. Collectively, subtle genetic differences related to glycosylation and acquisition of carbohydrates and iron/haem may contribute to the diversity of virulence and phenotypic traits among P. intermedia strains. These variations may also reflect versatile strategies for within-host adaptation of P. intermedia.

Copenhagen Rats Display Dominantly Inherited Yet Non-uniform Resistance to Spontaneous, Radiation-induced, and Chemically-induced Mammary Carcinogenesis.

BACKGROUND/AIM: Genetic and environmental factors interact to dictate the risk of cancer, and animal models are expected to provide avenues for identifying such interactions. The aim of the study was to clarify the genetic susceptibility of Copenhagen rats to spontaneous, radiation-induced, and chemically-induced mammary carcinogenesis. MATERIALS AND METHODS: Female Copenhagen and Sprague- Dawley rats and their F1 hybrids were subjected at age 7 weeks to γ-irradiation or intraperitoneal injection with 1-methyl-1-nitrosourea or were not treated, and palpable mammary tumours were diagnosed histologically. Data were pooled with previous data acquired for both nontreated and irradiated Sprague-Dawley rats. RESULTS: Radiation and 1-methyl-1-nitrosourea both significantly increased the incidence of mammary cancer in all strains. Copenhagen and F1 rats displayed a significantly lower incidence than Sprague-Dawley rats in all groups, with relatively higher incidence after irradiation. F1 rats exhibited significantly higher mammary cancer incidence than Copenhagen rats in the nontreated, but not the treated, groups. The interaction of the strain and exposure effects was suggested to be quasi-multiplicative. CONCLUSION: Copenhagen rats display non-uniform resistance to spontaneous, radiation-induced, and chemically-induced mammary carcinogenesis with dominant inheritance over Sprague-Dawley rats.

Potential differences in chitin synthesis ability cause different sensitivities to diflubenzuron among three strains of Daphnia magna.

Ecotoxicity testing of crustaceans using Daphnia magna has been implemented in the chemical management systems of various countries. While the chemical sensitivity of D. magna varies depending on genetically different clonal lineages, the strain used in ecotoxicity tests, including the acute immobilization test (OECD TG202), has not been specified. We hypothesized that comprehensive gene expression profiles could provide useful information on phenotypic differences among strains, including chemical sensitivity. To test this hypothesis, we performed mRNA sequencing on three different strains (NIES, England, and Clone 5) of D. magna under culture conditions. The resulting expression profile of the NIES strain was clearly different compared to the profiles of the other two strains. Gene ontology (GO) enrichment analysis suggested that chitin metabolism was significantly enriched in the NIES strain compared to that in the England strain. Consistent with the GO analysis, evidence of high levels of chitin metabolism in the NIES strain were observed across multiple levels of biological organization, such as expression of chitin synthase genes, chitin content, and chitinase activity, which suggested that the different strains would exhibit different sensitivities to chemicals used to inhibit chitin synthesis. We found that among all strains, the NIES strain was more tolerant to diflubenzuron, a chitin synthesis inhibitor, with a 14-fold difference in the 48 h-EC50 value for the acute immobilization test compared to the England strain. The present study demonstrates that the differences among strains in chitin metabolism may lead to sensitivity difference to diflubenzuron, and serves as a case study of the usefulness of comprehensive gene expression profiles in finding sensitivity differences.

Oxytocin variation and brain region-specific gene expression in a domesticated avian species.

The Bengalese finch was domesticated more than 250 years ago from the wild white-rumped munia (WRM). Similar to other domesticated species, Bengalese finches show a reduced fear response and have lower corticosterone levels, compared to WRMs. Bengalese finches and munias also have different song types. Since oxytocin (OT) has been found to be involved in stress coping and auditory processing, we tested whether the OT sequence and brain expression pattern and content differ in wild munias and domesticated Bengalese finches. We sequenced the OT from 10 wild munias and 11 Bengalese finches and identified intra-strain variability in both the untranslated and protein-coding regions of the sequence, with all the latter giving rise to synonymous mutations. Several of these changes fall in specific transcription factor-binding sites, and show either a conserved or a relaxed evolutionary trend in the avian lineage, and in vertebrates in general. Although in situ hybridization in several hypothalamic nuclei did not reveal significant differences in the number of cells expressing OT between the two strains, real-time quantitative PCR showed a significantly higher OT mRNA expression in the cerebrum of the Bengalese finches relative to munias, but a significantly lower expression in their diencephalon. Our study thus points to a brain region-specific pattern of neurochemical expression in domesticated and wild avian strains, which could be linked to domestication and the behavioral changes associated with it.

Identification of susceptibility loci for light-induced visual impairment in rats.

Bright light exposure in animals results in the selective degeneration of the outer retina, known as "retinal photic injury" (RPI). The susceptibility to RPI differs among rat strains. WKY rats display susceptibility to RPI with extensive retinal degeneration observed in the sagittal eye specimen, whereas LEW strain rats are resistant to it, showing only slight or no degeneration. In the present study, we first established an ethological screening method using the Morris water maze to discern differential susceptibility among the living rats. WKY and LEW were crossed to produce the first filial generation (F1) offspring. Maze-trained individuals were exposed to bright, white light. The screening test results demonstrated that the susceptibility to light-induced visual impairment in rats is a dominant Mendelian susceptibility trait, as F1 rats were susceptible to visual impairment like WKY rats. Therefore, F1 rats were backcrossed with recessive LEW to produce the first backcross offspring (BC1). Subsequent recurrent backcrossing while selecting for the susceptibility, indicated a segregation ratio of ca. 24% in BC1 and BC2 generations, indicating the involvement of two or more genes in the susceptibility. Further, microsatellite analysis of BC1-to-BC4 individuals using microsatellite markers mapped two susceptibility loci on chromosome segments 5q36 and 19q11-q12, named RPI susceptibility (Rpi)1 and Rpi2, respectively. This study provides an insight into mechanisms underlying differential susceptibility, which could help decipher the mechanism underlying the onset/progression of human age-related macular degeneration.

Repeated social defeat stress induces neutrophil mobilization in mice: maintenance after cessation of stress and strain-dependent difference in response.

BACKGROUND AND PURPOSE: Inflammation has been associated with stress-related mental disturbances. Rodent studies have reported that blood-borne cytokines are crucial for stress-induced changes in emotional behaviours. However, the roles and regulation of leukocytes in chronic stress remain unclear. EXPERIMENTAL APPROACH: Adult male C57BL/6N mice were subjected to repeated social defeat stress (R-SDS) with two protocols which differed in stress durations, stress cycles, and housing conditions, followed by the social interaction test. The numbers of leukocyte subsets in the bone marrow, spleen, and blood were determined by flow cytometry shortly after or several days after R-SDS. These leukocyte changes were studied in two strains of mice with different stress susceptibility, C57BL/6N and BALB/c mice. KEY RESULTS: R-SDS with both protocols similarly induced social avoidance in C57BL/6N mice. In the bone marrow, neutrophils and monocytes were increased, and T cells, B cells, NK cells, and dendritic cells were decreased with both protocols. In the blood, neutrophils and monocytes were increased with both protocols, whereas T cells, B cells, NK cells, and dendritic cells were decreased with one of these. Neutrophils and monocytes were also increased in the spleen. Changes in the bone marrow and increased levels of circulating neutrophils were maintained for 6 days after R-SDS. BALB/c mice showed greater social avoidance and increase in circulating neutrophils than C57BL/6N mice. CONCLUSION AND IMPLICATIONS: In two strains of mice, chronic stress induced neutrophil mobilization and its maintenance. These effects were strain-related and may contribute to the pathology of mental illness. LINKED ARTICLES: This article is part of a themed issue on Neurochemistry in Japan. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.4/issuetoc.

Effects of the cucumber mosaic virus 2a protein on aphid-plant interactions in Arabidopsis thaliana.

The cucumber mosaic virus (CMV) 2a RNA-dependent RNA polymerase protein has an additional function in Arabidopsis thaliana, which is to stimulate feeding deterrence (antixenosis) against aphids. Antixenosis is thought to increase the probability that aphids, after acquiring CMV particles from brief probes of an infected plant's epidermal cells, will be discouraged from settling and instead will spread inoculum to neighbouring plants. The amino acid sequences of 2a proteins encoded by a CMV strain that induces antixenosis in A. thaliana (Fny-CMV) and one that does not (LS-CMV) were compared to identify residues that might determine the triggering of antixenosis. These data were used to design reassortant viruses comprising Fny-CMV RNAs 1 and 3, and recombinant CMV RNA 2 molecules encoding chimeric 2a proteins containing sequences derived from LS-CMV and Fny-CMV. Antixenosis induction was detected by measuring the mean relative growth rate and fecundity of aphids (Myzus persicae) confined on infected and on mock-inoculated plants. An amino acid sequence determining antixenosis induction by CMV was found to reside between 2a protein residues 200 and 300. Subsequent mutant analysis delineated this to residue 237. We conjecture that the Fny-CMV 2a protein valine-237 plays some role in 2a protein-induced antixenosis.

[Multidisciplinary Approach to Aging].

Age-related decreases of various physiological functions have significant influence on activities of daily living (ADL) and QOL in elderly populations. Mechanisms of aging are currently the focus of many researchers in a wide range of studies. Researchers are trying to find novel ways to attenuate or delay aging in humans as well as to develop interventions for age-associated diseases. In this review, we briefly discuss the need for a multidisciplinary approach in aging research.

A histopathological analysis of spontaneous neoplastic and non-neoplastic lesions in aged male RccHan:WIST rats.

Histopathological information about spontaneous lesions in aged Hannover Wistar rats is limited. In this study, we describe spontaneous lesions found in 39 male RccHan:WIST rats used as a control in a carcinogenicity study. Neoplastic lesions were frequently seen in the endocrine system, such as pituitary adenomas in the pars distalis. This strain exhibited a high incidence of thymoma (10.3%), compared to other strains. We encountered an oligodendroglioma, a pituitary adenoma of the pars intermedia, and a prostate adenocarcinoma, which are comparatively rare in rats. While the variety and incidence of non-neoplastic lesions were similar to those in other strains, several interesting lesions occurred with relatively high incidence, including "harderianization" of the extraorbital lacrimal gland, common bile duct ectasia, and hyperplasia of pulmonary endocrine cells in the lung. Furthermore, comparative analyses demonstrated that the severity of chronic progressive nephropathy and murine progressive cardiomyopathy in RccHan:WIST rats was less than that in F344 rats.

Metabotropic glutamate receptor subtype 7 controls maternal care, maternal motivation and maternal aggression in mice.

The group III metabotropic glutamate receptor subtype 7 (mGlu7) is an important regulator of glutamatergic and GABAergic neurotransmission and known to mediate emotionality and male social behavior. However, a possible regulatory role in maternal behavior remains unknown to date. Adequate expression of maternal behavior is essential for successful rearing and healthy development of the young. By understanding genetic and neural mechanisms underlying this important prosocial behavior, we gain valuable insights into possible dysregulations. Using genetic ablation as well as pharmacological modulation, we studied various parameters of maternal behavior in two different mouse strains under the influence of mGlu7. We can clearly show a regulatory role of mGlu7 in maternal behavior. Naïve virgin female C57BL/6 mGlu7 knockout mice showed more often nursing postures and less spontaneous maternal aggression compared to their heterozygous and wildtype littermates. In lactating C57BL/6 wildtype mice, acute central activation of mGlu7 by the selective agonist AMN082 reduced arched back nursing and accelerated pup retrieval without affecting maternal aggression. In addition, in lactating CD1 wildtype mice the selective mGlu7 antagonist XAP044 increased both pup retrieval and maternal aggression. With respect to receptor expression levels, mGlu7 mRNA expression was higher in lactating vs virgin C57BL/6 mice in the prefrontal cortex, but not hypothalamus or hippocampus. In conclusion, these findings highlight a significant role of the mGlu7 receptor subtype in mediating maternal behavior in mice. Region-dependent studies are warranted to further extend our knowledge on the specific function of the brain glutamate system in maternal behavior.

Strain differences in histopathological features of lymphoid tissues of SD and F344 rats in a T cell-dependent antibody response assay of cyclophosphamide.

When conducting histopathological evaluation of lymphoid tissues, it is necessary to know the variability and strain differences in histological features of different sites of lymphoid tissues. To investigate in detail the variability of lymphoid tissues and strain differences of control rats as well as those of immune reactivity and sensitivity to immunosuppression, we performed a histopathological analysis of various lymphoid tissues in conjunction with the evaluation of immune function in a T cell-dependent antibody response (TDAR) assay with cyclophosphamide (CP) in Sprague Dawley (SD) and F344 rats. Six-week-old male SD and F344 rats were orally treated with CP at 0 (control) or 4 mg/kg/day for 28 days; keyhole limpet hemocyanin (KLH) was introduced intravenously on Days 14 and 23, and the serum concentrations of anti-KLH antibodies were measured. HE staining and immunohistochemistry for T-cell (CD3) and B-cell (CD45RA) markers were performed using tissues from the spleen, thymus, and various lymph nodes. In CP-treated rats of both strains, decreased concentrations of anti-KLH antibodies were observed. Histopathological analysis revealed decreased lymphocytes mainly in the B-cell area, and these changes induced by CP treatment were more prominent in the F344 rats than in the SD rats. The present study also demonstrated that some of the lymphoid tissues of the control F344 rats were less developed than those of the control SD rats, suggesting that F344 rats might be easily affected by CP-induced immunosuppression. This information concerning rat strain differences in lymphoid tissues will be useful in histopathological evaluation for drug-induced immunotoxicity.

Influence of principal stress effect on deformation and permeability of coal containing beddings under true triaxial stress conditions.

In situ stress is generally an anisotropic/true triaxial stress (σ 1 > σ 2 > σ 3). Bedding weakens the continuity and integrity of coal. It is critical to understand the mechanical behaviour and gas migration of coal under true triaxial stress conditions. We performed experiments of cubic coal samples to investigate the permeability evolution and mechanical behaviour of coal under true triaxial stress conditions by using newly developed true triaxial geophysical apparatus. We analysed the effect of principal stresses on deformation and permeability characteristics of coal containing bedding planes. The results show that volumetric strain, stress states and bedding directions determine the permeability comprehensively. The variable quantity of strain was the largest in the direction normal to the bedding plane. The expansion or compression degree was characterized by the difference between the major and minor principal strain (ɛ 1 - ɛ 3). Essentially, this represents the difficulty degree with regard to coal being compressed at the initial stress state and the deformation degree in ɛ 1 and ɛ 3 direction. The variation of (ɛ 1 - ɛ 3) was consistent with that of permeability. Under an identical true triaxial stress condition, permeability was smaller when larger stress was applied in the direction normal to the bedding plane. Additionally, stress level in the direction parallel to the bedding planes and the directions between stresses in the direction parallel to the bedding planes and the flow direction also affect the permeability and strain. By solving lateral expansion coefficient, coal also exhibited anisotropic properties.

Male C57BL6/N and C57BL6/J Mice Respond Differently to Constant Light and Running-Wheel Access.

Previous studies have shown that exposure to circadian disruption produces negative effects on overall health and behavior. More recent studies illustrate that strain differences in the behavioral and physiological responses to circadian disruption exist, even if the strains have similar genetic backgrounds. As such, we investigated the effects of constant room-level light (LL) with running-wheel access on the behavior and physiology of male C57BL6/J from Jackson Laboratories and C57BL6/N from Charles River Laboratories mice. Mice were exposed to either a 12:12 light-dark (LD) cycle or LL and given either a standard home cage or a cage with a running-wheel. Following 6 weeks of LD or LL, their response to behavioral assays (open-field, light-dark box, novel object) and measures of metabolism were observed. Under standard LD, C57BL6/J mice exhibited increased locomotor activity and reduced exploratory behavior compared to C57BL6/N mice. In LL, C57BL6/J mice had greater period lengthening and increased anxiety, while C57BL6/N mice exhibited increased weight gain and no change in exploratory behavior. C57BL6/J mice also decreased exploration with running-wheel access while C57BL6/N mice did not. These results further demonstrate that C57BL/6 substrains exhibit different behavioral and physiological responses to circadian disruption and wheel-running access.

Thickening of T1 Precipitates during Aging of a High Purity Al⁻4Cu⁻1Li⁻0.25Mn Alloy.

The age hardening response of a high-purity Al⁻4Cu⁻1Li⁻0.25Mn alloy (wt. %) during isothermal aging without and with an applied external load was investigated. Plate shaped nanometer size T1 (Al2CuLi) and θ' (Al2Cu) hardening phases were formed. The precipitates were analyzed with respect to the development of their structure, size, number density, volume fraction and associated transformation strains by conducting transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) studies in combination with geometrical phase analysis (GPA). Special attention was paid to the thickening of T1 phase. Two elementary types of single-layer T1 precipitate, one with a Li-rich (Type 1) and another with an Al-rich (Defect Type 1) central layer, were identified. The results show that the Defect Type 1 structure can act as a precursor for the Type 1 structure. The thickening of T1 precipitates occurs by alternative stacking of these two elementary structures. The thickening mechanism was analyzed based on the magnitude of strain associated with the precipitation transformation normal to its habit plane. Long-term aging and aging under load resulted in thicker and structurally defected T1 precipitates. Several types of defected precipitates were characterized and discussed. For θ' precipitates, a ledge mechanism of thickening was observed. Compared to the normal aging, an external load applied to the peak aged state leads to small variations in the average sizes and volume fractions of the precipitates.

Susceptibility of mice strains to oxidative stress and neurotransmitter activity induced by Plasmodium berghei.

This study investigated the susceptibility of female C57Bl/6 and Swiss Albino mice to oxidative stress and neurotransmitters activity induced by Plasmodium berghei. On day 9 p.i. with P. berghei infected erythrocytes, the mice reduced in weight. This weight loss was markedly higher in SW mice and reached about -14%. Also, the infection was able to cause oxidative damage to the brain tissue. Catalase activity as well as glutathione, malondialdehyde and nitric oxide levels were different in the two mice strains. Moreover, the brain content of neurotransmitters, epinephrine, norepinephrine, dopamine and serotonin in mice brain was higher in SW mice than B6 mice. We concluded that, the strain of mice is one factor that could alter the response of mice to P. berghei infection.

PI3K and Inhibitor of Apoptosis Proteins Modulate Gentamicin- Induced Hair Cell Death in the Zebrafish Lateral Line.

Inner ear hair cell death leads to sensorineural hearing loss and can be a direct consequence of aminoglycoside antibiotic treatment. Aminoglycosides such as gentamicin are effective therapy for serious Gram-negative bacterial infections such as some forms of meningitis, pneumonia, and sepsis. Aminoglycosides enter hair cells through mechanotransduction channels at the apical end of hair bundles and initiate intrinsic cell death cascades, but the precise cell signaling that leads to hair cell death is incompletely understood. Here, we examine the cell death pathways involved in aminoglycoside damage using the zebrafish (Danio rerio). The zebrafish lateral line contains hair cell-bearing organs called neuromasts that are homologous to hair cells of the mammalian inner ear and represents an excellent model to study ototoxicity. Based on previous research demonstrating a role for p53, Bcl2 signaling, autophagy, and proteasomal degradation in aminoglycoside-damaged hair cells, we used the Cytoscape GeneMANIA Database to identify additional proteins that might play a role in neomycin or gentamicin ototoxicity. Our bioinformatics analysis identified the pro-survival proteins phosphoinositide-dependent kinase-1 (PDK1) and X-linked inhibitor of apoptosis protein (Xiap) as potential mediators of gentamicin-induced hair cell damage. Pharmacological inhibition of PDK1 or its downstream mediator protein kinase C facilitated gentamicin toxicity, as did Xiap mutation, suggesting that both PI3K and endogenous Xiap confer protection. Surprisingly, aminoglycoside-induced hair cell death was highly attenuated in wild type Tupfel long-fin (TL fish; the background strain for the Xiap mutant line) compared to wild type ∗AB zebrafish. Pharmacologic manipulation of p53 suggested that the strain difference might result from decreased p53 in TL hair cells, allowing for increased hair cell survival. Overall, our studies identified additional steps in the cell death cascade triggered by aminoglycoside damage, suggesting possible drug targets to combat hearing loss resulting from aminoglycoside exposure.

Cold Temperature Encoding by Cutaneous TRPA1 and TRPM8-Carrying Fibers in the Mouse.

Previous research identified TRPM8 and TRPA1 cold transducers with separate functions, one being functional in the non-noxious range and the second one being a nociceptive transducer. TRPM8-deficient mice present overt deficits in the detection of environmental cool, but not a lack of cold avoidance and TRPA1-deficient mice show clear deficits in some cold nocifensive assays. The extent of TRPA1's contribution to cold sensing in vivo is still unclear, because mice lacking both TRPM8 and TRPA1 (DKO) were described with unchanged cold avoidance from TRPM8-/- based on a two-temperature-choice assay and by c-fos measurement. The present study was designed to differentiate how much TRPM8 alone and combined TRPA1 and TRPM8 contribute to cold sensing. We analyzed behavior in the thermal ring track assay adjusted between 30 and 5°C and found a large reduction in cold avoidance of the double knockout mice as compared to the TRPM8-deficient mice. We also revisited skin-nerve recordings from saphenous-nerve skin preparations with regard to nociceptors and thermoreceptors. We compared the frequency and characteristics of the cold responses of TRPM8-expressing and TRPM8-negative C-fiber nociceptors in C57BL/6J mice with nociceptors of TRPM8-deficient and DKO mice and found that TRPM8 enables nociceptors to encode cold temperatures with higher firing rates and larger responses with sustained, static component. In TRPM8-/-, C-fiber cold nociceptors were markedly reduced and appeared further reduced in DKO. Nevertheless, the remaining cold responses in both knockout strains were similar in their characteristics and they were indifferent from the TRPM8-negative cold responses found in C57BL/6J mice. TRPM8 had a comparably essential role for encoding cold in thermoreceptors and lack of TRPM8 reduced response magnitude, peak and mean firing rates and the incidence of thermoreceptors. The encoding deficits were similar in the DKO strain. Our data illustrate that lack of TRPA1 in TRPM8-deficient mice results in a disproportionately large reduction in cold avoidance behavior and also affects the incidence of cold encoding fiber types. Presumably TRPA1 compensates for lack of TRPM8 to a certain extent and both channels cooperate to cover the entire cold temperature range, making cold-temperature encoding by TRPA1-although less powerful-synergistic to TRPM8.

An ELISA for quantifying quail IgY and characterizing maternal IgY transfer to egg yolk in several quail strains.

In avian species, maternal blood immunoglobulin Y (IgY) is transferred to the egg yolks of maturing oocytes, but the mechanism underlying this transfer is unknown. To gain insight into the mechanism of maternal IgY transfer in quail, we established an enzyme-linked immunosorbent assay (ELISA) for the quantitation of quail IgY. We characterized strain differences in blood and egg yolk IgY concentrations and exogenously injected IgY-Fc uptakes into egg yolks. A specific rabbit polyclonal antibody to quail IgY was raised for the ELISA. Blood and egg yolk IgY concentrations were determined in six quail strains (one inbred strain, L; four closed population strains, AWE, DB, PS, WE; one commercial strain, Commercial). The birds were also injected with digoxigenin-labeled quail IgY-Fc, and its uptakes into laid eggs were compared. The strain difference in blood and egg yolk IgY concentrations was at most 2.5-fold, between PS and AWE. The rank order of IgY concentrations was AWE, Commercial, DB, L≥WE≥PS. A significant positive correlation (|R|=0.786) between individual blood IgY and egg yolk IgY and the concentrated egg yolk IgY (1.5-2-fold) against blood IgY was observed. Interestingly, there was a significant inverse correlation (|R|=0.452) between injected IgY-Fc uptakes and the blood IgY concentration, implying competition of the injected IgY-Fc and blood IgY in the process of IgY uptake into egg yolks. In conclusion, we successfully determined blood and egg yolk IgY concentrations in various quail strains by a quail IgY-specific ELISA. The concentrated egg yolk IgY against the blood IgY and the inverse relationship of exogenous IgY-Fc uptake against the blood IgY supports the existence of a selective IgY transport mechanism in avian maturing oocytes.

Sex differences in constitutive mRNA levels of CYP2B22, CYP2C33, CYP2C49, CYP3A22, CYP3A29 and CYP3A46 in the pig liver: Comparison between Meishan and Landrace pigs.

Breed and sex differences in hepatic mRNA levels of cytochrome P450 (CYP) isoforms (CYP2B22, CYP2C33, CYP2C49, CYP3A22, CYP3A29 and CYP3A46) were examined in 5-month-old Meishan, Landrace, and their crossbred F1 (LM and ML) pigs. Serum testosterone levels in male Meishan, LM, and ML pigs were 2.5-3.5-fold higher than in Landrace pigs. CYP3A46 mRNA was breed-specifically detected only in Landrace, LM, and ML pigs. In Meishan, LM, and ML pigs only, male-predominant expressions of CYP2B22, CYP2C33, CYP2C49 and CYP3A29 mRNAs were observed; CYP3A22 mRNA expression showed the opposite pattern. Male-dominant mRNA expression was also observed in LM and ML pigs for CYP3A46. The sex differences in CYP mRNA levels in Meishan pigs disappeared when males were castrated and were restored by testosterone propionate (TP) administration to the castrated males. In Landrace pigs, TP administration to castrated males and intact females significantly increased the levels of CYP2B22, CYP2C33, and CYP3A46 mRNAs. Immature (1-month-old) pigs showed no breed or sex differences in CYP mRNA expressions. The results demonstrated that androgen is an important determinant of sex-associated expression of several CYPs and suggested that breed differences in sex-associated expression could be caused by differences in serum androgen level and by other genetic traits.