Actions of sex steroids on kisspeptin expression and other reproduction-related genes in the brain of the teleost fish European sea bass.

Kisspeptins are well known as mediators of the coordinated communication between the brain-pituitary axis and the gonads in many vertebrates. To test the hypothesis that gonadal steroids regulate kiss1 and kiss2 mRNA expression in European sea bass (a teleost fish), we examined the brains of gonad-intact (control) and castrated animals, as well as castrated males (GDX) and ovariectomized females (OVX) that received testosterone (T) and estradiol (E2) replacement, respectively, during recrudescence. In GDX males, low expression of kiss1 mRNA is observed by in situ hybridization in the caudal hypothalamus (CH) and the mediobasal hypothalamus (MBH), although hypothalamic changes in kiss1 mRNA levels were not statistically different among the groups, as revealed by real-time PCR. However, T strongly decreased kiss2 expression levels in the hypothalamus, which was documented in the MBH and the nucleus of the lateral recess (NRLd) in GDX T-treated sea bass males. Conversely, it appears that E2 evokes low kiss1 mRNA in the CH, while there were cells expressing kiss2 in the MBH and NRLd in these OVX females. These results demonstrate that kisspeptin neurons are presumably sensitive to the feedback actions of sex steroids in the sea bass, suggesting that the MBH represents a major site for sex steroid actions on kisspeptins in this species. Also, recent data provide evidence that both positive and negative actions occur in key factors involved in sea bass reproductive function, including changes in the expression of gnrh-1/gonadotropin, cyp19b, er and ar genes and sex steroid and gonadotropin plasma levels in this teleost fish.

Selective acylation of plasma membrane proteins of Mycoplasma agalactiae: the causal agent of agalactia.

Revealed by in vivo labeling with (14)C-palmitic acid, about 15 acylated proteins were identified in the plasma membrane of Mycoplasma agalactiae (type strain PG2), including the major component p40. Triton X-114 phase partitioning and Western blotting demonstrated the amphiphilic properties of the acyl proteins and showed that they were also antigenic components. Chemical analyses of fatty acids bound to proteins revealed the following selectivity order within acylation: stearic acid (18:0) > linoleic acid (18:2c) approximately palmitic acid (16:0) > oleic acid (18:1c) > myristic acid (14:0), with 16:0 and 18:1c preferred for the O-acylation and 18:0 for the N-acylation. The ratio [O-ester- + amide-bound acyl chains]/O-ester-linked chains being close to 1.4 as well as the presence of S-glycerylcysteine suggest that acyl proteins in M. agalactiae are true lipoproteins containing N-acyl diacyl glycerylcysteine, probably processed by a mechanism analogous to that described for Gram-negative eubacteria.

Evaluation of a new toothbrush concept with regard to bacterial elimination. Imprint study using scanning electron microscopy.

The efficacy of a new toothbrush filament layout concept (Topix, Peridental, France) was compared to that of a standard vertical-tuft toothbrush. Bacterial and exogenous deposit elimination were used as parameters of efficacy. 30 dental surgery students took part in the study. Plaque index scores were calculated according to a pre-defined protocol. Imprints of the 6 anterior teeth were taken before and after brushing with the 2 types of brushes, without toothpaste or rinsing. Imprints were examined by scanning electron microscopy (SEM). 12 h after brushing, imprint examination revealed bacterial flora polymorphism and the amount of dental plaque accumulated at the cervical third zone of teeth. Automated quantification in this zone of exogenous bodies showed that after brushing with vertical-tuft and cross-tuft brushes, there remained 1.26 mm2 and 0.83 mm2 of dental plaque, squamae, and blood residues, respectively. The plaque index values correlated to scanning electron microscopic observations. There was no significant difference in terms of efficacy between the cross-tuft and vertical-tuft toothbrushes.