Effect of 13-cis-Retinoic Acid on the Hamster Flank Organ

Administration of 13-cis-retinoic acid subcutaneously to mature male hamsters produced a marked decrease in the size of the sebaceous glands of the flank organ, without diminution of other hormonally dependent structures of the flank organs. Subcutaneous administration of 13-cis-retinoic acid to female hamsters treated simultaneously with injections of testosterone enanthate prevented the androgen-induced growth of the flank organ sebaceous glands but did not prevent the growth of other hormonally dependent structures such as the dermal pigment cells and large pigmented hair follicles. The sebaceous gland progressively decreased during 3weeks of treatment and the effect persisted at least 3weeks after cessation of treatment but was completely reversed by 6 mos after treatment. In vitro studies of testosterone metabolism by hamster flank organ indicated the lack of inhibition of 5a-reduction by 13-cis-retinoic acid. It seems likely that systemically administered 13-cis-retinoic acid, unlike antiandrogens, exerts a specific extrahormonal effect on the sebaceous glands of the hamster flank organ without affecting other androgen dependent cells

Metabolism of Testosterone-4- 14C by Hamster Skin and Flank Organ**From the Department of Dermatology, Skin and Cancer unit, Mount Sinai Medical Center, Miami Beach, Florida, 33140

The metabolism of testosterone-4-14C by hamster skin and flank organ was studied; flank organ metabolized more testostrone than an equal weight of adjacent skin. Androstenedione,† androsterone, androstanedione, dihydrotestosterone (DHT), and 3α-androstanediol were identified by chromatography and reverse isotopic dilution as metabolites formed by flank organ. The metabolites of flank organ and general body skin showed identical chromatographic mobilities. Flank organ produced 4 times as much DHT as an equal weight of adjacent skin. The ratio of total 5α-metabolites formed by both tissues was the same as the DHT ratio, indicating that the greater amount of DHT formed is due to greater formation of 5α-metabolites, in general. In contrast, both tissues produced the same amount of 17-ketosteroids from testosterone and had similar DNA contents, suggesting that the observed difference in 5α-reduction was not due to differences in cellularity but to a greater capacity of the flank organ to reduce testosterone. No 3β-hydroxysteroids, the formation of which has been reported in human skin were found

Biodynamic Studies of Hamster Flank Organ Growth: Hormonal Influences

The biodynamic response of flank organs of male and female hamsters to androgenic stimulation has been studied by autoradiographic and electron microscopic techniques, as well as by routine histology and gross observation. Intraperitoneal administration of 2.5mg of testosterone on alternate days resulted in bilateral increase in palpable bulk, and pigmentation of flank organs of females, males, and castrated males. Topical application of testosterone, dihydrotestosterone (DHT), methyltestosterone, or androstenedione to one flank organ of females resulted in unilateral stimulation of sebaceous gland growth and pigmentation. Androsterone, epiandrosterone, and progesterone did not cause flank organ growth or increased pigmentation when applied topically. Histologic changes in flank organs of castrated males following testosterone administration are described. Auto0radiographic studies indicate a decrease in the labeling index of flank organ sebaceous gland cells within 20 hours after castration and a subsequent significant increase in the labeling index within 10 hours after a single intraperitoneal administration of 2.5mg of testosterone. Pigmentation of flank organs is due to the presence of dendritic cells in the dermis which contain dense structures resembling stage IV melanosomes

Draft Genome Sequence of the Marine Pathogen \u3cem\u3eVibrio coralliilyticus\u3c/em\u3e RE22

Vibrio coralliilyticus RE22 is a causative agent of vibriosis in larval bivalves. We report here the draft genome sequence of V. coralliilyticus RE22 and describe additional virulence factors that may provide insight into its mechanism of pathogenicity

Draft Genome Sequence of the Shellfish Larval Probiotic Bacillus pumilus RI06-95

Bacillus pumilus RI06-95 is a marine bacterium isolated in Narragansett, Rhode Island, which has shown probiotic activity against marine pathogens in larval shellfish. We report the genome of B. pumilus RI06-95, which provides insight into the microbe’s probiotic ability and may be used in future studies of the probiotic mechanism

Draft Genome Sequence of Aliiroseovarius crassostreae CV919-312, the Causative Agent of Roseovarius Oyster Disease (Formerly Juvenile Oyster Disease)

Aliiroseovarius crassostreae CV919-312 is a marine alphaproteobacterium and the causative agent of Roseovarius oyster disease. We announce here the draft genome sequence of A. crassostreae CV919-312 and identify potential virulence genes involved in pathogenicity

Draft Genome Sequence of Loktanella Maritima Strain YPC211, a Commensal Bacterium of the American Lobster (\u3cem\u3eHomarus Americanus\u3c/em\u3e)

Loktanella maritima strain YPC211 was isolated from the American lobster (Homarus americanus). We report here the draft genome sequence for L. maritima YPC211 and identify genes of potential importance to its role within the microbial community

Draft Genome Sequence of Bowmanella denitrificans JL63, a Bacterium Isolated from Whiteleg Shrimp (\u3cem\u3eLitopenaeus vannamei\u3c/em\u3e) That Can Inhibit the Growth of Vibrio Parahaemolyticus

Bowmanella denitrificans strain JL63 was isolated from a whiteleg shrimp (Litopenaeus vannamei) and was determined to have antibacterial activity against an acute hepatopancreatic necrosis disease (AHPND) strain of Vibrio parahaemolyticus. Here, we report the draft genome sequence of this strain and identify genes that are potentially involved in its antibacterial activity

Draft Genome Sequence of the Putative Marine Pathogen Thalassobius sp. I31.1

Thalassobius sp. I31.1 is a putative pathogen involved in epizootic shell disease in the American lobster (Homarus americanus). We report here the draft genome sequence for Thalassobius sp. I31.1 and provide insight into its metabolism and links to environmental pollutant degradation

Membrane Localization of the Repeats-in-Toxin (RTX) Leukotoxin (LtxA) Produced by Aggregatibacter Actinomycetemcomitans

The oral bacterium, Aggregatibacter actinomycetemcomitans, which is associated with localized aggressive periodontitis, as well as systemic infections including endocarditis, produces numerous virulence factors, including a repeats-in-toxin (RTX) protein called leukotoxin (LtxA), which kills human immune cells. The strains of A. actinomycetemcomitans most closely associated with disease have been shown to produce the most LtxA, suggesting that LtxA plays a significant role in the virulence of this organism. LtxA, like many of the RTX toxins, can be divided into four functional domains: an N-terminal hydrophobic domain, which contains a significant fraction of hydrophobic residues and has been proposed to play a role in the membrane interaction of the toxin; the central domain, which contains two lysine residues that are the sites of post-translational acylation; the repeat domain that is characteristic of the RTX toxins, and a C-terminal domain thought to be involved in secretion. In its initial interaction with the host cell, LtxA must bind to both cholesterol and an integrin receptor, lymphocyte function-associated antigen-1 (LFA-1). While both interactions are essential for toxicity, the domains of LtxA involved remain unknown. We therefore undertook a series of experiments, including tryptophan quenching and trypsin digestion, to characterize the structure of LtxA upon interaction with membranes of various lipid compositions. Our results demonstrate that LtxA adopts a U-shaped conformation in the membrane, with the N- and C-terminal domains residing outside of the membrane. © 2018 Brown et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited