bluuebunny/crossref_metadata_2025 huggingface dataset:
Tamoxifen as an Emerging Endocrine Disruptor
Authors: Maradonna Francesca , Batti Stefania , Marino Maria , Mita Damiano Gustavo , Carnevali Oliana
Published: April 2009

The effect of tamoxifen (TAM) on the black goby Gobius niger exposed to different contaminants was analyzed by investigating the response of a set of biomarkers involved in reproduction and cell recovery. While the effects of TAM are well known in mammalian breast and endometrial cells (with severe consequences on physiology), few contrasting data are available for fish. In this work the expression of vitellogenin (vtg), estrogen receptor α (ERα), cytochrome P4501A1 (CYP1A1), and heat shock protein 70 (HSP70) genes was evaluated in fish treated with TAM alone or co‐injected with nonylphenol, estradiol, and β‐naphtoflavone. The induction of vtg observed in male fish treated with estrogens was significantly lowered by the co‐injection of TAM. ERα and HSP70 gene expressions were significantly upregulated in all experimental groups; however, TAM treatment did not change CYP1A1 gene expression. Together these data confirm the mixed estrogenic/anti‐estrogenic action of TAM, indicating its interference in fish reproduction and physiology.
Thyroid Status Can Influence Brain Mast Cell Population
Authors: Baccari Gabriella Chieffi , Monteforte Rossella , Pinelli Claudia , Santillo Alessandra , Polese Gianluca , Rastogi Rakesh K.
Published: April 2009

Neuroanatomical mapping as well as the influence of thyroid status on brain mast cell distribution and detectable mast cell number in adultRana esculentais studied. Treatment with tizoxin (T4) does not modify number or activational state of brain mast cells, whereas administration of the antithyroid agent 6‐n‐propyl‐2‐thiouracil induces a significant increase (up to 40%) in the mast cell number within the telencephalon and diencephalon. Hypophysectomy induces a significant decrease (up to 65%) of mast cells in all brain regions, whereas the pituitary homogenate augments their number. The results suggest that the pituitary–thyroid axis may be involved in the regulation of brain mast cell population.
Major Genomic Events and Their Consequences for Vertebrate Evolution and Endocrinology
Authors: Larhammar Dan , Sundström Görel , Dreborg Susanne , Daza Daniel Ocampo , Larsson Tomas A.
Published: April 2009

Comparative studies of proteins often face the problem of distinguishing a true orthologue (species homologue) from a paralogue (a gene duplicate). This identification task is particularly challenging for endocrine peptides and neuropeptides because they are short and usually have several invariant positions. For some peptide families, this has led to a terminology with peptide names relating to the first species where a specific peptide sequence was determined, such as chicken or salmon gonadotropin‐releasing hormone, or names that highlight amino acid differences, e.g., Lys‐vasopressin. With accumulating information from multiple species, such a terminology becomes almost impenetrable for nonexperts and difficult even for aficionados. The sequenced genomes offer a new way to distinguish orthologues and paralogues, namely by location of the genes relative to neighboring genes on the chromosomes. In addition, the genome databases can ideally provide a complete listing of the family members in each species. Many vertebrate gene families have expanded in the two basal tetraploidizations (2R) and the teleost fish third tetraploidization (3R), after which some vertebrate lineages have lost some of the duplicates. We review here some peptide families (neuropeptide Y, oxytocin–vasopressin, and somatostatin) where genomic information helps simplify nomenclature. This approach is useful also for other gene families, such as peptide receptors.
Molecular Cloning and mRNA Distribution of Pituitary Adenylate Cyclase‐activating Polypeptide (PACAP)/PACAP‐related Peptide in the Lungfish
Authors: Lee L. T. O. , Tam J. K. V. , Chan D. W. , Chow B. K. C.
Published: April 2009

In this article, we report the isolation of a full‐length cDNA clone encoding pituitary adenylate cyclase‐activating polypeptide (PACAP)/PACAP‐related peptide (PRP) from lungfish Protopterus dolloi. When comparing the deduced amino acid sequences, the lungfish PACAP was found to be highly conserved with other vertebrates; however, the PRP shares only lower levels of sequence identity with known PRP sequences. Consistently in phylogenetic analysis, the lungfish PRP, similar to sturgeon PRP, fails to cluster with other PRPs. In addition to the full‐length clone, another cDNA encoding a short precursor that lacks the first 32 amino acids of the PRP was also isolated. Interestingly, similar isoforms were also identified in several nonmammalian vertebrates, and it was suggested that exon skipping of PRP/PACAP transcripts was a mechanism that regulated the expression ratio of PACAP to PRP in nonmammalian vertebrates. By real‐time PCR, both long and short PRP/PACAP transcripts were found almost exclusively in the brain, and the short isoform is the more abundant transcript (3.7 times more), indicating that PACAP is the major product produced in lungfish brain. The expression patterns of lungfish and previously studied frog PRP/PACAP suggest that the PRP/PACAP gene in the tetrapod lineage may first express in the central nervous system; in the process of evolution, the functions of these peptides diversified and were later found in other tissues.
Morphological and Functional Alterations in Testes and Efferent Ducts of Homogametic Rainbow Trout Oncorhynchus mykiss Walbaum
Authors: Galas Jerzy F. , Hejmej Anna , Glogowski Jan , Bilińska Barbara
Published: April 2009

In the present study we analyzed the morphology of testes and efferent ducts as well as the localization of androgen receptors (AR) in the tissues of XY, YY, and XX male rainbow trout Oncorhynchus mykiss Walbaum. Testes of the XX trout differed distinctly from those of XY and YY males; the interstitial space was very narrow and lumina of the tubules were densely filled with spermatozoa. There was no efferent duct. The nuclei of Leydig cells and endothelial cells of blood vessels were positively stained for AR, and this was confirmed by quantitative image analysis. Differences in the AR immunoexpression levels indicate the differences in the levels of androgens produced by the Leydig cells, possibly based on the chromosomal constitution of the testes concerned.
Steroid Biosynthesis within the Frog Brain
Authors: Rego Jean‐Luc Do , Seong Jae Young , Burel Delphine , Luu‐The Van , Larhammar Dan , Tsutsui Kazuyoshi , Pelletier Georges , Tonon Marie‐Christine , Vaudry Hubert
Published: April 2009

There is now clear evidence that the brain, similar to the adrenal gland, gonads, and placenta, is a steroidogenic organ. Notably in the frog brain, the presence of various steroidogenic enzymes has been detected by immunohistochemistry in specific populations of neurons and/or glial cells. These steroidogenic enzymes are biologically active, as shown by the ability of brain tissue explants to convert [3H]pregnenolone into various radiolabeled steroids. The frog brain has also been extensively used as a model to study the mechanism of regulation of neurosteroidogenesis by neurotransmitters and neuropeptides. It has been demonstrated that the biosynthesis of neurosteroids is inhibited by γ‐aminobutyric acid (GABA), acting through GABAAreceptors, and neuropeptide Y, acting through Y1 receptors, and is stimulated by the octadecaneuropeptide (ODN), acting through central‐type benzodiazepine receptors, triakontatetraneuropeptide (TTN), acting through peripheral‐type benzodiazepine receptors, and vasotocin, acting through V1a‐like receptors. These data indicate that some of the neurophysiological effects of neurotransmitters and neuropeptides may be mediated through modulation of neurosteroid biosynthesis.
Developmental and Thyroid Hormone‐induced Expression of Preprotemporin Genes in the Skin of Japanese Mountain Brown Frog Rana ornativentris
Authors: Ohnuma Aya , Conlon J. Michael , Iwamuro Shawichi
Published: April 2009

Temporins are a group of small, highly hydrophobic, antimicrobial peptides widely distributed in the skin of frogs from the Ranidae family. In order to examine the mechanisms of regulation of temporin gene expression, we measured expression levels of preprotemporin mRNA in the skin of the Japanese mountain brown frog Rana ornativentris, using a semiquantitative RT‐PCR system. Preprotemporin mRNAs were not detected in skin prior to the onset of metamorphosis but their levels increased markedly during metamorphosis, reaching a maximum at the stages of metamorphic climax, suggesting a correlation with thyroid hormone concentrations. Consequently, we examined direct effects of triiodothyronine (T3) on in vivo preprotemporin gene expression. Treatment of adult animals with 2 × 10−9 mol/L T3 for 48 h raised the preprotemporin mRNA levels in skin by 1.5‐fold compared with untreated controls.
Elevation of the Plasma Level of Insulin‐like Growth Factor‐I with Reproductive Maturation prior to Initiation of Spawning Migration of Chum Salmon
Authors: Onuma Takeshi A. , Makino Keita , Ban Masatoshi , Ando Hironori , Fukuwaka Masa‐aki , Azumaya Tomonori , Swanson Penny , Urano Akihisa
Published: April 2009

When, where, and how oceanic chum salmon initiate spawning migration is unknown although gonadal development and elevation of the activity of the pituitary–gonadal axis (PG‐axis) are essential. Insulin‐like growth factor‐I (IGF‐I) is a somatotropic signal that interacts with the PG‐axis for gametogenesis. We thus examined the plasma level of IGF‐I in immature and maturing chum salmon in the Bering Sea and the Gulf of Alaska. The maturing adults which had maturing gonads left the Bering Sea for the natal river by the end of summer, because almost all fish were immature in September. The plasma level of IGF‐I and corresponding body size in the maturing adults were two‐ to threefold that of immature fish. The plasma IGF‐I level correlated positively with the pituitary contents of follicle‐stimulating hormone and the plasma levels of 11‐ketotestosterone and estradiol‐17β. Therefore, the plasma level of IGF‐I increased with elevation of the PG‐axis activity prior to the initiation of spawning migration from the Bering Sea. Circulatory IGF‐I from visceral organs may inform the status of body growth to the PG‐axis for gonadal development that is inseparable from decision of chum salmon whether to initiate homing behavior from the Bering Sea or not to initiate spawning migration by the coming spawning season.
Plasma Corticosterone Levels of Semipalmated Sandpiper Calidris pusilla Overwintering in a Tropical Coastal Lagoon of Northeastern Venezuela
Authors: Mata Astolfo , Marín Gedio , Rodríguez Jon Paul , Yuraí Guerrero Hilda , Cardillo Elizabeth
Published: April 2009

Semipalmated sandpiper Calidris pusilla arrives on the coasts of Venezuela between the middle of August and early September, staying there until May when birds prepare for vernal migration. To investigate possible relationships between corticosterone levels and body mass changes during preparation for migration, we sampled birds during wintering (January) and vernal premigration (May) over 2 years. Body mass and fat increased significantly from wintering to vernal premigration in both years. Capture stress levels of corticosterone varied between 30 and 150 ng mL−1, the highest being during wintering. These results strongly suggest that increase in body mass of C. pusilla during preparation for vernal migration in a tropical environment was promoted by a decreased corticosterone secretion response to stress.
Stimulation of Gut Immune System by Early Administration of Probiotic Strains in Dicentrarchus labrax and Sparus aurata
Authors: Abelli Luigi , Randelli Elisa , Carnevali Oliana , Picchietti Simona
Published: April 2009

Early feeding (started during gut metamorphosis and establishment of the hypothalamic–pituitary–interrenal axis) with probiotic‐supplemented diets, besides modifying the intestinal microflora, evoked profound effects on the physiology of fish larvae. Using rotifers and Artemia as living vectors, the autochthonous bacterium Lactobacillus delbrueckii delbrueckii or a multispecies probiotic formulation (autochthonous Lactobacillus fructivorans+Lactobacillus plantarum from human feces) were orally administered to sea bass and gilthead sea bream larvae, respectively. The treatments enhanced larval rearing (significantly increased body weight, decreased cortisol levels, and improved stress response compared with controls) and the immune system. In sea bass, the probiotic raised intestinal T cells, in keeping with increased total body TcR‐β transcripts, and increased acidophilic granulocytes concomitant to lower transcription of pro‐inflammatory genes (IL‐1‐β, TGF‐β, IL‐10, Cox‐2). In sea bream, the multispecies probiotic formulation raised intestinal immunoglobulin (Ig+) cells and acidophilic granulocytes mainly belonging to the MAb G7+ phagocytic population. These results point to stimulatory actions of probiotics on the gut immune system that are devoid of harmful effects and that correlate with improvement of fry survival.
Evolution of the Growth Hormone–Prolactin–Somatolactin System in Relation to Vertebrate Tetraploidizations
Authors: Ocampo Daza Daniel , Sundström Görel , Larsson Tomas A. , Larhammar Dan
Published: April 2009

Gene sequences from several species representing major vertebrate groups were used to create phylogenetic trees for the growth hormone family of peptide hormones as well as the growth hormone receptor family. These analyses show that both the peptide and receptor families were formed through local duplications in early vertebrate evolution and chromosome duplications.
Early Duplications of Opioid Receptor and Peptide Genes in Vertebrate Evolution
Authors: Larhammar Dan , Dreborg Susanne , Larsson Tomas A. , Sundström Görel
Published: April 2009

The opioid receptor family in mammals has four members called delta, kappa, mu, and NOP (the nociceptin/orphanin receptor). We show here that they arose from a common ancestral gene through quadruplication of a large chromosomal region, presumably in the two basal vertebrate tetraploidizations. The four opioid peptide precursor genes have a more complicated evolutionary history involving chromosomal rearrangements but nevertheless seem to have arisen in the same time period as the receptors. Thus the system of opioid peptides and receptors was already established approximately 450 Ma at the dawn of gnathostome evolution.
Identification, Biosynthesis, and Function of 7α‐Hydroxypregnenolone, a New Key Neurosteroid Controlling Locomotor Activity, in Nonmammalian Vertebrates
Authors: Tsutsui Kazuyoshi , Haraguchi Shogo , Inoue Kazuhiko , Miyabara Hitomi , Suzuki Saori , Ogura Yuki , Koyama Teppei , Matsunaga Masahiro , Vaudry Hubert
Published: April 2009

It is now clearly established that steroids can be synthesized de novo by the brain and the peripheral nervous systems. Such steroids are called neurosteroids, and de novo neurosteroidogenesis from cholesterol is a conserved property of vertebrate brains. Our studies over the past decade have demonstrated that the brain expresses several kinds of steroidogenic enzymes and produces a variety of neurosteroids in submammalian species. However, the biosynthetic pathway of neurosteroids in nonmammalian vertebrates as well as in mammals may be still incompletely mapped out. We recently found that the brain of newts and quail actively produces 7α‐hydroxypregnenolone, a novel bioactive neurosteroid, from pregnenolone. Interestingly, 7α‐hydroxypregnenolone stimulates locomotor activity by means of the dopaminergic system. Subsequently, we demonstrated that melatonin regulates synthesis of 7α‐hydroxypregnenolone, a key factor for induction of locomotor activity, thus inducing diurnal locomotor changes.
The in Vitro and in Ovo Effects of Environmental Illumination and Temperature on the Melatonin Secretion from the Embryonic Chicken Pineal Gland
Authors: Faluhelyi Nándor , Matkovits Attila , Párniczky Andrea , Csernus Valér
Published: April 2009

Pineal glands of chicken embryos were placed into a perifusion system for 4 days. The pineal glands were illuminated or exposed to elevated temperature for 8 or 12 h during the in vitro experiment and/or in ovo. Both daily illumination and repeated elevations of environmental temperature transitionally inhibited melatonin release before, and controlled the phase of melatonin rhythm after, the 17th day of embryonic life (E17). In addition, the in ovo rhythmic illumination applied before E13 advances the development of the circadian hormone synthesis.
Central Effects of Trout Tachykinins on Heart Rate Variability in Trout
Authors: Lancien Frédéric , Mimassi Nagi , Conlon John Michael , Le Mével Jean‐Claude
Published: April 2009

Recent studies in trout have shown that tachykinins might be selectively implicated in important neuroregulatory functions related to the central control of ventilation. In teleost fish, cardiorespiratory coupling probably contributes to heart rate variability (HRV), and the hypoventilatory effects observed after central injection of tachykinins suggest that these peptides also may produce changes in HRV. Consequently, the present study was undertaken to compare the central actions of picomolar doses (25–250 pmol) of trout neuropeptide gamma (NPγ), substance P (SP), and neurokinin A (NKA) on HRV in unanesthetized rainbow trout. Compared to vehicle‐injected trout, Poincaré plot analysis of HRV demonstrated that intracerebroventricular injection of NPγ dose dependently increased HRV. SP evoked a significant elevation of HRV but only at the highest dose (250 pmol). In contrast, NKA was without any effect on HRV. In conclusion, these results suggest that NPγ may be selectively implicated in the central control of HRV in trout.
Adrenocorticotropic Hormone, Melanocyte‐stimulating Hormone, and the Melanocortin Receptors: Revisiting the Work of Robert Schwyzer
Authors: Dores Robert M.
Published: April 2009

In 1977 Dr. Robert Schwyzer wrote the review ACTH: A Short Introductory Review, which provided a reference point for current structure/function studies on the interactions between adrenocorticotropic hormone and α‐melanocyte‐stimulating hormone and the melanocortin receptors. This mini review will evaluate how the predictions made in the 1977 review have held up and also propose a mechanism to explain the ligand selectivity properties of the melanocortin receptors.
Structural and Functional Evolution of the Pineal Melatonin System in Vertebrates
Authors: Falcón Jack , Besseau Laurence , Fuentès Michael , Sauzet Sandrine , Magnanou Elodie , Boeuf Gilles
Published: April 2009

In most species daily rhythms are synchronized by the photoperiodic cycle. They are generated by the circadian system, which is made of a pacemaker, an entrainment pathway to this clock, and one or more output signals. In vertebrates, melatonin produced by the pineal organ is one of these outputs. The production of this time‐keeping hormone is high at night and low during the day. Despite the fact that this is a well‐preserved pattern, the pathways through which the photoperiodic information controls the rhythm have been profoundly modified from early vertebrates to mammals. The photoperiodic control is direct in fish and frogs and indirect in mammals. In the former, full circadian systems are found in photoreceptor cells of the pineal organ, retina, and possibly brain, thus forming a network where melatonin could be a hormonal synchronizer. In the latter, the three elements of a circadian system are scattered: the photoreceptive units are in the eyes, the clocks are in the suprachiasmatic nuclei of the hypothalamus, and the melatonin‐producing units are in the pineal cells. Intermediate situations are observed in sauropsids. Differences are also seen at the level of the arylalkylamine N‐acetyltransferase (AANAT), the enzyme responsible for the daily variations in melatonin production. In contrast to tetrapods, teleost fish AANATs are duplicated and display tissue‐specific expression; also, pineal AANAT is special—it responds to temperature in a species‐specific manner, which reflects the fish ecophysiological preferences. This review summarizes anatomical, structural, and molecular aspects of the evolution of the melatonin‐producing system in vertebrates.
Immunohistochemical Localization of Hydroxysteroid Sulfotransferase and Sulfatase in the Brain ofRana esculentaTadpoles
Authors: Cevasco Alessandra , Pittaluga Aurora , Rego Jean‐Luc Do , Luu‐The Van , Pelletier Georges , Vaudry Hubert , Mandich Alberta
Published: April 2009

Sulfation plays a major role in regulating the activity of various neurosteroids, including pregnenolone and dehydroepiandrosterone. The present report describes the immunohistochemical distribution of two enzymes involved in the control of neurosteroid sulfation, hydroxysteroid sulfotransferase (HST) and unconjugated steroid enzyme sulfatase (STS), in the brain of the European green frogRana esculentaduring development. HST and STS immunoreactivity were detected from stage VIII‐XII. At this early stage, HST‐positive fibers were seen in the glomerular layer and the basal rhombencephalon. Subsequently, at stage XIII‐XV, HST‐ and STS‐immunoreactive fibers were vizualized in the accessory olfactory bulb. At stage XVI‐XVIII, STS‐positive cell bodies were observed in the periventricular region of the diencephalon. These observations indicate that the enzymes controlling sulfation of hydroxysteroids are expressed in the frog brain during development.
Hormone‐mediated Reproductive Behavior in the Red‐bellied Newt
Authors: Kikuyama Sakae , Hasunuma Itaru , Toyoda Fumiyo , Haraguchi Shogo , Tsutsui Kazuyoshi
Published: April 2009

Hormonal involvement in the performance of reproductive behavior of the red‐bellied newt Cynops pyrrhogaster is described. The sexually developed male newt is likely to recognize the sexually responsive female newt by a yet unidentified substance released from the oviduct, secretion of this substance being stimulated by prolactin (PRL) and estrogen. At the initial stage of courtship behavior, the male newt vibrates his tail vigorously in front of the female partner. This action is elicited by PRL and androgen and is enhanced by another hormonal factor, arginine vasotocin (AVT). Both PRL and AVT were shown to act centrally to elicit this behavior. A recently discovered neurosteroid, 7α‐hydroxypregnenolone, was also revealed to be an important factor for eliciting tail vibrating behavior. During courtship, the male newt emits a decapeptide pheromone that attracts the female partner. The synthesis of this attractant by the abdominal gland is promoted by PRL and androgen and its release from the cloaca is elicited by AVT. The responsiveness to the pheromone of the vomeronasal epithelial cells of the female newt is enhanced by PRL and estrogen. Toward the final stage of courtship, the male newts deposits spermatophores, which are picked up through the cloacal orifice of the female newt. AVT induces the discharge of spermatophores from the cloaca. Thus, PRL, AVT, androgen, estrogen, and the neurosteroid, 7α‐hydroxypregnenolone, are considered to be important factors for the performance of reproductive behavior in the red‐bellied newt.
Identification of a Second Messenger of Crustacean Hyperglycemic Hormone Signaling Pathway in the Kuruma Prawn Marsupenaeus japonicus
Authors: Nagai Chiaki , Asazuma Hideaki , Nagata Shinji , Nagasawa Hiromichi
Published: April 2009

To address the signaling pathway of crustacean hyperglycemic hormone (CHH) in the kuruma prawn Marsupenaeus japonicus, we measured the intracellular cAMP and cGMP levels in the hepatopancreas, one of the major target tissues of CHH. Removal of CHH‐producing cells by bilateral eyestalk ablation decreased intracellular cGMP levels, while little effect on cAMP was observed in the tissue. Similarly, exposure to recombinant CHH significantly increased the cGMP level of the hepatopancreas in vitro, while little change was observed in cAMP. These results suggest that cGMP, rather than cAMP, mediates the CHH signal in hepatopancreas of M. japonicus.
Endocrine Disruption in Aquatic Vertebrates
Authors: Kloas Werner , Urbatzka Ralph , Opitz Robert , Würtz Sven , Behrends Thomas , Hermelink Björn , Hofmann Frauke , Jagnytsch Oana , Kroupova Hana , Lorenz Claudia , Neumann Nadja , Pietsch Constanze , Trubiroha Achim , Van Ballegooy Christoph , Wiedemann Caterina , Lutz Ilka
Published: April 2009

Environmental compounds can interfere with endocrine systems of wildlife and humans. The main sink of such substances, called endocrine disrupters (ED), are surface waters. Thus, aquatic vertebrates, such as fish and amphibians, are most endangered. ED can adversely affect reproductive biology and the thyroid system. ED act by (anti)estrogenic and (anti)androgenic modes of action, resulting in abnormal sexual differentiation and impaired reproduction. These effects are mainly driven by direct interferences of ED with sex steroid receptors rather than indirectly by impacting synthesis and bioavailability of sex steroids, which in turn might affect the hypothalamic–pituitary–gonadal axis. Recent findings reveal that, in addition to the human‐produced waste of ED, natural sources, such as parasites and decomposition of leaves, also might act as ED, markedly affecting sexual differentiation and reproduction in fish and amphibians. Although the thyroid system has essential functions in both fish and amphibians, amphibian metamorphosis has been introduced as the most sensitive model to detect thyroidal ED; no suitable fish model exists. Whereas ED may act primarily on only one specific endocrine target, all endocrine systems will eventually be deregulated as they are intimately connected to each other. The recent ecotoxicological issue of pharmaceutically active compounds (PhACs) present in the aquatic environment indicates a high potential for further endocrine modes of action on aquatic vertebrates by ED derived from PhACs, such as glucocorticoids, progestins, and ß‐agonists.
Characterization of Feeding‐delaying Factors from the Silkworm Bombyx mori
Authors: Nagata Shinji , Morooka Nobukatsu , Matsumoto Sumihiro , Nagasawa Hiromichi
Published: April 2009

In several phytophagous insects, feeding behavior occurs regularly. Recently, we demonstrated that feeding behavior in larvae of the silkworm Bombyx mori had a regular frequency. To address the control of the feeding cycle in B. mori, we aimed to characterize factors influencing feeding initiation and termination. Injection of extracts of the midgut, foregut, and fat body into starved Bombyx larvae delayed the initiation of feeding. This result indicates the presence in these tissues of factors capable of decreasing the likelihood of feeding initiation.
Involvement of Endocannabinoid CB1 Receptor in the Modulation of Stress Responses Related to Xenoestrogen Exposure
Authors: Palermo Francesco A. , Angelini Mario , Cottone Erika , Virgili Matteo , Franzoni Maria Fosca , Mosconi Gilberto , Polzonetti‐Magni Alberta Maria
Published: April 2009

The endocannabinoid system, through the cannabinoid receptor CB1, is involved in the modulation of adaptive responses to environmental conditions. However, little is known about the role of the cannabinergic system, particularly CB1 receptor expression, in relation to the effects induced by xenoestrogens concerning the reproductive axis. Our results demonstrate that only 10−8 mol/L of 17β‐estradiol was able to induce significantly higher levels of CB1A mRNA, while no effects were found after treatment with 4‐nonylphenol (10−8 or 10−6 mol/L); moreover, mRNA expression titers of CB1B did not show any significant change. The estrogenic effects of treatments were evidenced by a dose‐dependent induction of plasma hepatic vitellogenin titers. It can be concluded that low doses of estrogens, and possibly of xenoestrogens, may increase endocannabinoid signaling pathways.
Does Atrazine Affect Larval Development and Sexual Differentiation of South African Clawed Frogs?
Authors: Kloas Werner , Lutz Ilka , Urbatzka Ralph , Springer Tim , Krueger Hank , Wolf Jeffrey , Holden Larry , Hosmer Alan
Published: April 2009

The potential impact of atrazine (ATZ) on gonadal malformations in larval Xenopus laevis has been controversially discussed, and a hypothesis has been generated that ATZ might induce the estrogen‐synthesizing enzyme aromatase, leading to feminization or demasculinization. Recently, extensive long‐term studies clearly indicate that no adverse effect of ATZ on larval development and sexual differentiation could be found. Therefore, to determine potential transient impacts of ATZ on sexual differentiation processes, short‐term exposures were conducted using tadpoles treated for 4 days with ATZ at 25 μg/L. The expression levels of the key players for sexual differentiation in amphibians were determined in the brain, assessing aromatase, 5α‐reductase type 1 (S1) and type 2 (S2), and the gonadotropins luteinizing hormone and follicle‐stimulating hormone, and in the gonads, measuring aromatase, S1, and S2, by means of quantitative RT‐PCR. No significant changes in any of these parameters have been found, implicating, in accordance with recent long‐term exposures, that no aromatase induction by ATZ could be observed, and it seems likely that no further endocrine mechanism of ATZ affecting sexual differentiation in X. laevis exists.
Regulation of Expression of the Myo‐inositol Monophosphatase 1 Gene in Osmoregulatory Tissues of the European Eel Anguilla anguilla after Seawater Acclimation
Authors: Kalujnaia Svetlana , Cramb Gordon
Published: April 2009

Previous microarray studies in our laboratory identified a number of genes that were differentially expressed in “silver” eels after transfer from freshwater (FW) to seawater (SW). A group of genes, which are related to the synthesis, processing, and transport of certain known osmolytes in mammalian cells, have been identified. One gene implicated with osmolyte production is myo‐inositol monophosphatase (IMPA1). The aim of this study was to compare the expression of IMPA1 in the major osmoregulatory tissues (intestine, gill, and kidney) as fish move between FW and SW environments. No difference in IMPA1 gene expression was observed in any tissues 6 h after eel transfer to SW; however, after 2 days acclimation, a 1.9‐ and a 2.5‐fold increase in mRNA expression was found in kidney and gill, respectively. These elevated levels were maintained for up to 5 months (4.9‐ and 3.4‐fold, respectively) after SW transfer. No IMPA1 mRNA expression was detected in the intestine. Western blot analysis confirmed the IMPA1 protein was upregulated in the gill, but no changes in protein abundance were detected in the kidney 5 months after SW transfer. Our studies have revealed a potential role for IMPA1 in salinity adaptation in the European eel.
The Compensatory Growth in Juveniles of Sea Bass
Authors: Ferrando Sara , Gambardella Chiara , Bottaro Massimiliano , Saroglia Marco , Terova Genciana , Tagliafierro Grazia
Published: April 2009

The aim of this work was to investigate the distribution of regulative molecules in the stomach of juvenile Dicentrarchus labrax during compensatory growth, using immunohistochemical methods. Antisera against galanin, neuropeptide Y, ghrelin, leptin, and serotonin were used on fasted and refed D. labrax. The results show a characteristic distributive pattern for the sought molecules in fish refed after 35 days of fasting, with a high increased presence of both ghrelin and leptin.
Vertebrate Sex Steroid Receptors: Evolution, Ligands, and Neurodistribution
Authors: Guerriero Giulia
Published: April 2009

This review focuses on our current understanding of vertebrate sex steroid receptors, with an emphasis on their evolutionary relationships. These relationships are discussed based on nucleotide and amino acid sequence data, which provide clues to the process by which structure–function relations have originated, evolved, and been maintained over time. The importance of the distribution of sex steroid receptors in the vertebrate brain is discussed using the example of androgen receptor sites and their relatively conserved localizations in the vertebrate brain.
The Sociolinguistics of Ethnicity in New York City
Authors: Becker Kara , Coggshall Elizabeth L.
Published: April 2009

This paper reviews the vast literature from sociolinguistics on ethnicity in New York City. Prior work falls into two camps: first, early work in dialectology on New York City English that often erased ethnic distinctions and presented a homogenous, white city; and second, later work investigating minority ethnic groups, often speakers of Languages Other than English. Here we summarize both threads of work, and suggest that the 1965 Immigration and Nationality Act, which significantly changed the composition of immigrants in New York City, marks a turning point from work concerned with whites to that concerned with other ethnic groups. We also promote newer conceptions of ethnicity that view it as a fluid category concerned with the construction and/or destruction of boundaries. New York City's tremendous ethnolinguistic diversity makes it a unique site for explorations into ethnic identity practices.
Characterization and ACE‐Inhibitory Activity of Amaranth Proteins
Authors: Tiengo A. , Faria M. , Netto F.M.
Published: April 2009

ABSTRACT:  Amaranth seeds have been considered as an excellent alternative or complementary source of food protein due to their balanced amino acid composition. However, their potential as a source of bioactive peptides has not been explored. The present study is aimed at characterizing and evaluating the activity of the angiotensin converting enzyme inhibitor of the amaranth protein concentrate and of hydrolysates produced with Alcalase. The protein concentrate, after simulated gastrointestinal digestion, showed lower angiotensin converting enzyme‐inhibitory activity (IC50 of 0.439 ± 0.018 mg protein/mL and 0.475 ± 0.021 mg protein/mL, for untreated and heat treated protein concentrate, respectively) than the hydrolysates produced with Alcalase, before and after simulated gastrointestinal digestion (IC50 0.118 ± 0.009, 0.123 ± 0.007, 0.137 ± 0.002, and 0.176 ± 0.014 mg protein/mL, respectively). The simulated gastrointestinal digestion (pepsin–pancreatin) did not significantly alter the angiotensin‐converting enzyme inhibiting activity of the Alcalase hydrolysates, suggesting that the peptides of the hydrolysates were resistant to gastrointestinal hydrolysis. These results highlight the angiotensin converting enzyme‐inhibitory potential of amaranth proteins, which is an indication of their health‐promoting potential.
Consumer Liking of Fruit Juices with Different Açaí (Euterpe oleracea Mart.) Concentrations
Authors: Sabbe Sara , Verbeke Wim , Deliza Rosires , Matta Virginia M. , Van Damme Patrick
Published: April 2009

ABSTRACT:  Overall liking, flavor, and perceived healthiness of one newly developed fruit juice with high açaí content (40% açaí) and 5 commercially available fruit juices with lower (4% to 20%) açaí concentrations were evaluated by consumers in Belgium. General trends for the overall sample were examined by means of analysis of variance, whereas individual consumer preferences were evaluated using internal preference mapping and hierarchical cluster analysis. The relative contribution of flavor and perceived health benefits as predictors of consumers' overall liking of the 6 açaí‐based fruit juices was estimated through linear regression analysis. The results showed a negative relationship between the juices' overall liking and their açaí concentrations. Although the vast majority of consumers preferred the juices having a low açaí content (4% to 5% açaí), a small consumer segment liked the juice with 40% açaí. Flavor or taste experience superseded consumers' perceived health benefits as the primary determinant of the fruit juices' overall liking. The impact of perceived health benefits on the overall liking of the açaí juices decreased with higher taste dissatisfaction.
The Beneficial Effect of Propolis on Fat Accumulation and Lipid Metabolism in Rats Fed a High‐Fat Diet
Authors: Ichi I. , Hori H. , Takashima Y. , Adachi N. , Kataoka R. , Okihara K. , Hashimoto K. , Kojo S.
Published: April 2009

ABSTRACT:  This study examined whether propolis, which had many biological activities, affected body fat and lipid metabolism. Four‐week‐old Wistar rats were fed a control or propolis diet for 8 wk. The control group was fed a high‐fat diet, the low and the high group were fed a high‐fat diet supplemented with 0.5% (w/w) and 0.05% (w/w) propolis, respectively. The weight of total white adipose tissue of the high group was lower than that of the control group. The level of PPARγ protein in the adipose tissues of the high group was significantly lower than that of the control group. In plasma and the liver, the high group showed a significantly reduced level of cholesterol and triglyceride compared to the control group. The liver PPARα protein level of the high group was significantly higher than that of the control group. The liver HMG‐CoA reductase protein in the high group was also significantly lower than that in the control group. Results from rats on an olive oil loading test were used to investigate whether propolis inhibited triglyceride absorption. The serum triglyceride level of the group, which received propolis corresponding to the daily dose of the high group, was significantly lower than that of the control group. It is possible that the administration of propolis improves the accumulation of body fat and dyslipidemia via the change of the expression of proteins involved in adipose depot and lipid metabolism.
Effect of Guava (Psidium guajava L.) Leaf Extract on Glucose Uptake in Rat Hepatocytes
Authors: Cheng Fang‐Chi , Shen Szu‐Chuan , Wu James Swi‐Bea
Published: April 2009

ABSTRACT:  People in oriental countries, including Japan and Taiwan, boil guava leaves (Psidium guajava L.) in water and drink the extract as a folk medicine for diabetes. The present study investigated the enhancement of aqueous guava leaf extract on glucose uptake in rat clone 9 hepatocytes and searched for the active compound. The extract was eluted with MeOH‐H2O solutions through Diaion, Sephadex, and MCI‐gel columns to separate into fractions with different polarities. The uptake test of 2‐[1‐14C] deoxy‐D‐glucose in rat clone 9 hepatocytes was performed to evaluate the hypoglycemic effect of these fractions. The active compound was identified by nuclear magnetic resonance analysis and high‐performance liquid chromatography (HPLC). The results revealed that phenolics are the principal component of the extract, that high polarity fractions of the guava leaf extract are enhancers to glucose uptake in rat clone 9 hepatocytes, and that quercetin is the major active compound. We suggest that quercetin in the aqueous extract of guava leaves promotes glucose uptake in liver cells, and contributes to the alleviation of hypoglycemia in diabetes as a consequence.
Validation of an Improved Method for Detection of Campylobacter jejuni in Foods
Authors: Odongo R. , Reilly S.S. , Gilliland S.E.
Published: April 2009

ABSTRACT:  Campylobacter jejuni ATCC 29428 and 33560 were inoculated separately into beef muscle, ground beef, and chicken skin to yield approximately 10 to 100 CFU/g of food sample. The samples were stored at 4 °C for 10 d. On days 0, 3, 7, and 10, enrichment cultures in Bolton broth supplemented with antibiotics, with and without blood supplementation were made for each sample, for 24 and 48 h following the Food and Agricultural Products Center (FAPC) and the Food and Drug Administration (FDA) protocols. Enumeration of the organisms in the enrichment cultures was done on Campylobacter Karmali selective agar after 24 and 48 h of enrichment to compare the extent of growth in both protocols. There were no significant differences between counts recovered using the FDA and the FAPC methods for detection of Campylobacter jejuni for either strain in any of the food products tested (P > 0.05). No significant differences were observed in performance of enrichment broth supplemented with and without blood (P > 0.05). After 48 h of enrichment, the counts recovered were similar for all products. The organisms were detectable on all days of storage in raw chicken skin, beef, and ground beef samples after both 24 and 48 h of enrichment. The results from the FAPC method for detection of C. jejuni from food were not different from the FDA method. While in the proposed method incubation at 37 °C was adequate for the strains tested it is recommended that both enrichment temperatures be used for naturally contaminated samples to ensure detection of all strains that might be present.
Effective Correction of Mass Bias for Rhenium Measurements by MC‐ICP‐MS
Authors: Poirier André , Doucelance Régis
Published: April 2009

The geochemistry of Re‐Os and the recent use of Re as a non‐traditional stable isotope both need accurate and precise quantification of 187Re/185Re ratios. This paper reports rhenium isotopic data obtained from the analysis of a standard solution and geological samples by MC‐ICP‐MS. We show that measured isotopic ratios are modified by matrix effects that cannot be accounted for by the standard solution bracketing technique. The bias resulting from measurements on a spiked (185Re‐enriched) sample is shown to alter the apparent Re concentration by several percent. When spiking samples and calibrators with tungsten, simultaneous measurement of tungsten and rhenium isotopes compensates for the matrix‐induced modification of mass bias. Rhenium and tungsten are shown to have different fractionation factors. This may be due to the fact that the two elements fractionate in a different but systematic way, or that the reference isotopic ratios used for elemental Re and W are incoherent with one another. The consistency of fractionation through time can be used to obtain an empirical relationship between W and Re measured ratios from a standard solution to obtain a sample's fractionation‐corrected 187Re/185Re spiked ratio on samples containing pg g−1 levels of Re, even if some matrix capable of affecting mass bias remains in the final solution.
Capital Structure Decisions: Which Factors Are Reliably Important?
Authors: Frank Murray Z. , Goyal Vidhan K.
Published: April 2009

This paper examines the relative importance of many factors in the capital structure decisions of publicly traded American firms from 1950 to 2003. The most reliable factors for explaining market leverage are: median industry leverage (+ effect on leverage), market‐to‐book assets ratio (−), tangibility (+), profits (−), log of assets (+), and expected inflation (+). In addition, we find that dividend‐paying firms tend to have lower leverage. When considering book leverage, somewhat similar effects are found. However, for book leverage, the impact of firm size, the market‐to‐book ratio, and the effect of inflation are not reliable. The empirical evidence seems reasonably consistent with some versions of the trade‐off theory of capital structure.
On the Use of Multifactor Models to Evaluate Mutual Fund Performance
Authors: Huij Joop , Verbeek Marno
Published: April 2009

We show that multifactor performance estimates for mutual funds suffer from systematic biases and argue that these biases are a result of miscalculating the factor premiums. Because the factor proxies are based on hypothetical stock portfolios and do not incorporate transaction costs, trade impact, and trading restrictions, the factor premiums are either over‐ or underestimated. We argue that factor proxies based on mutual fund returns rather than on stock returns provide better benchmarks to evaluate professional money managers.
The Conditional Beta and the Cross‐Section of Expected Returns
Authors: Bali Turan G. , Cakici Nusret , Tang Yi
Published: April 2009

We examine the cross‐sectional relation between conditional betas and expected stock returns for a sample period of July 1963 to December 2004. Our portfolio‐level analyses and the firm‐level cross‐sectional regressions indicate a positive, significant relation between conditional betas and the cross‐section of expected returns. The average return difference between high‐ and low‐beta portfolios ranges between 0.89% and 1.01% per month, depending on the time‐varying specification of conditional beta. After controlling for size, book‐to‐market, liquidity, and momentum, the positive relation between market beta and expected returns remains economically and statistically significant.
International Evidence on Financial Derivatives Usage
Authors: Bartram Söhnke M. , Brown Gregory W. , Fehle Frank R.
Published: April 2009

Theory predicts that nonfinancial corporations might use derivatives to lower financial distress costs, coordinate cash flows with investment, or resolve agency conflicts between managers and owners. Using a new database, we find that traditional tests of these theories have little power to explain the determinants of corporate derivatives usage. Instead, we show that derivative usage is determined endogenously with other financial and operating decisions in ways that are intuitive but not related to specific theories for why firms hedge. For example, derivative usage helps determine the level and maturity of debt, dividend policy, holdings of liquid assets, and international operating hedging.
Rich Sensitivities: An Analysis of Conflict Among Women in Feminist Memoir*
Authors: TAYLOR JUDITH
Published: April 2009

Alors que le mouvement nord‐américain des femmes est surtout connu pour ses efforts en vue de transformer les relations sociales entre les femmes et les hommes, ses partisanes ont également mis l'accent sur la reformulation des relations entre les femmes. Utilisant une source de données novatrice, les mémoires du mouvement social, l'auteure souligne la profondeur de la déception que les féministes s'infligent les unes aux autres. Les mémorialistes débattent des notions provenant du mouvement et du courant principal voulant que les femmes soient compétentes socialement. Cet article présente le concept d'«idéation relationnelle» pour décrire la façon dont les mémorialistes féministes analysent d'une manière critique la compréhension de la socialité des femmes tenue pour acquise et aiguisent leurs désirs d'une nouvelle éthique sociale entre elles.

While the North American women's movement is most known for its efforts to transform social relations between women and men, its adherents have also focused on remaking relations among women. Using an innovative data source, social movement memoir, this paper indicates the depth of disappointment feminists cause one another. Memoirists dispute notions found in the movement and mainstream that women are socially capable. The paper offers the concept “relational ideation” to describe the way feminist memoirists critically examine taken for granted understandings of women's sociality and amplify their desires for a new social ethic among them.