Ghrelin-like peptide with fatty acid modification and O-glycosylation in the red stingray, Dasyatis akajei

<p>Abstract</p> <p>Background</p> <p>Ghrelin (GRLN) is now known to be an appetite-stimulating and growth hormone (GH)-releasing peptide that is predominantly synthesized and secreted from the stomachs of various vertebrate species from fish to mammals. Here, we report a GRLN-like peptide (GRLN-LP) in a cartilaginous fish, the red stingray, <it>Dasyatis akajei</it>.</p> <p>Results</p> <p>The purified peptide contains 16 amino acids (GVSFHPQPRS¹⁰TSKPSA), and the serine residue at position 3 is modified by <it>n</it>-octanoic acid. The modification is the characteristic of GRLN. The six N-terminal amino acid residues (GVSFHP) were identical to another elasmobranch shark GRLN-LP that was recently identified although it had low identity with other GRLN peptides. Therefore, we designated this peptide stingray GRLN-LP. Uniquely, stingray GRLN-LP was <it>O</it>-glycosylated with mucin-type glycan chains [<it>N</it>-acetyl hexosamine (HexNAc)₃hexose(Hex)₂] at threonine at position 11 (Thr-11) or both serine at position 10 (Ser-10) and Thr-11. Removal of the glycan structure by <it>O</it>-glycanase made the <it>in vitro </it>activity of stingray GRLN-LP decreased when it was evaluated by the increase in intracellular Ca²⁺concentrations using a rat GHS-R1a-expressing cell line, suggesting that the glycan structure plays an important role for maintaining the activity of stingray GRLN-LP.</p> <p>Conclusions</p> <p>This study reveals the structural diversity of GRLN and GRLN-LP in vertebrates.</p

Expression Patterns of PACAP and PAC1R Genes and Anorexigenic Action of PACAP1 and PACAP2 in Zebrafish

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide with potent suppressive effects on feeding behavior in rodents, chicken, and goldfish. Teleost fish express two PACAPs (PACAP1, encoded by the adcyap1a gene, and PACAP2, encoded by the adcyap1b gene) and two PACAP receptors (PAC1Rs; PAC1Ra, encoded by the adcyap1r1a gene, and PAC1Rb, encoded by the adcyap1r1b gene). However, the mRNA expression patterns of the two PACAPs and PAC1Rs, and the influence and relationship of the two PACAPs on feeding behavior in teleost fish remains unclear. Therefore, we first examined mRNA expression patterns of PACAP and PAC1R in tissue and brain. All PACAP and PAC1Rs mRNAs were dominantly expressed in the zebrafish brain. However, adcyap1a mRNA was also detected in the gut and testis. In the brain, adcyap1b and adcyap1r1a mRNA levels were greater than that of adcyap1a and adcyap1r1b, respectively. Moreover, adcyap1b and adcyap1r1a mRNA were dominantly expressed in telencephalon and diencephalon. The highest adcyap1a mRNA levels were detected in the brain stem and diencephalon, while the highest levels of adcyap1r1b were detected in the cerebellum. To clarify the relationship between PACAP and feeding behavior in the zebrafish, the effects of zebrafish (zf) PACAP1 or zfPACAP2 intracerebroventricular (ICV) injection were examined on food intake, and changes in PACAP mRNA levels were assessed against feeding status. Food intake was significantly decreased by ICV injection of zfPACAP1 (2 pmol/g body weight), zfPACAP2 (2 or 20 pmol/g body weight), or mammalian PACAP (2 or 20 pmol/g). Meanwhile, the PACAP injection group did not change locomotor activity. Real-time PCR showed adcyap1 mRNA levels were significantly increased at 2 and 3 h after feeding compared with the pre-feeding level, but adcyap1b, adcyap1r1a, and adcyap1r1b mRNA levels did not change after feeding. These results suggest that the expression levels and distribution of duplicated PACAP and PAC1R genes are different in zebrafish, but the anorexigenic effects of PACAP are similar to those seen in other vertebrates

Prognostic Significance of Tumor Volume and Microvessel Density in Squamous Cell Carcinoma of Uterine Cervix

The purpose of the present study was to evaluate the prognostic significance and relationship between tumor volume and microvessel density in squamous cell carcinoma of the uterine cervix. The estimated tumor volume (TV) in 57 patients (22 stage Ib, 18 stage IIa, and 17 stage IIb) had radical hysterectomy was calculated on the assumption that the tumor mass was spheroid. The micro-vessel density (MVD) was evaluated as the ratio of endothelial area immunoreactive to factor-VIII related antigen (von Willebrand factor) to whole image area measured by computer-aided image analysis system. Tumor volume ranged from 0.1 to 41.0 cm3 (median 3.6 cm3) and MVD from 0.33 to 2.95 % (median 0.85 %). A significantly larger median TV was noted in women with positive pelvic node metastasis (6.3 vs 2.6 cm3, P=0.0228), parametrial invasion (8.9 vs 0.8 cm3, P4 cm3, respectively; and 96.2% and 61.3% (P=0.0022) between tissue specimens with a MVD of ?0.8% and >0.8%, respectively. A combined TV of >4 cm3 and MVD >0.8% further deteriorated 5 year survival rate (42.1% vs 94.7%, P<0.0001). Multivariate analysis indicated TV and MVD as independent risk factor in this series (P=0.041, P=0.03, respectively). Our current findings suggested that TV and MVD are independent prognostic factors in women with cervical carcinoma who underwent radical hysterectomy. These prognostic factors may be clinically useful for the selection of high-risk patients who need extensive adjuvant therapy

Classification of Participants Based on Increase–Decrease Rate Model of Reaction Time to Personality Trait Words

In this experiment, we tried to measure personality by reaction time (RT) to stimuli of personality trait words. There were interindividual and intraindividual differences in the factors that caused the reaction time to fluctuate. The intraindividual differences for personality trait words were caused by changes due to circumstances for the same participant. The increased stimulus reaction time (sRT) model for simple reaction time was used as an index to indicate personality traits. As a result, participants could be classified into two major hierarchical clusters. The participants in Cluster 1 showed innovative dominance. The participants in Cluster 2 were obedient and conservative. The independent variable was measured by the physiological index using sRT for classify the participants. Participants in Cluster 2 had a reduced stress response to the experiment and showed a tendency to be compliant. Moreover, immediately after the RT measurement session with a laptop computer started, participants in Cluster 1 showed decreased HEG and increased amylase values and had a somewhat negative attitude. The physiological dependent variable were measured by using salivary amylase and hemoencephalography (HEG). And, the psychological dependent variable was the Big Five personality inventory. All of them ware using to verify the participant&rsquo;s classification. Participants in Cluster 2 had significantly higher conscientiousness than those in Cluster 1. Therefore, we suggest that it is possible to classify personality traits from RT by using sRT based on intraindividual differences

Differences and similarities between mammalian and fish endozepinergic system

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