Nitrite and nitrate are formed by endogenous synthesis in the human intestine

Studies of nitrate balance in humans and analyses of fecal and ileostomy samples indicate that nitrite and nitrate are formed de novo in the intestine, possibly by heterotrophic nitrification. These findings significantly alter our previous conceptions of human exposure to nitrite and suggest an even wider role for nitrite in the etiology of human cancer.     

Homology of retractile filaments of vampire squid

The axial filament nerves of Vampyroteuthis infernalis are joined to two separate parts of the brain. One branch of the nerve, apparently efferent, arises from the anterior portion of the middle subesophageal mass, and the other, apparently afferent. enters the ventral magnocellular lobe. Since this innervation is entirely different from that of the arms, the filaments can no longer be considered homologous with the arms. The validity and primitive nature of the order Vampyromorpha, therefore, needs to be reexamined.     

Gonad histology and plasma steroid profiles in wild New Zealand freshwater eels (Anguilla dieffenbachii and A. australis) before and at the onset of the natural spawning migration. I. Females*

To determine steroid profiles in immature and maturing female eels from the wild, non-migratory and migratory New Zealand longfinned (Anguilla dieffenbachii) and shortfinned (A. australis) eels were caught and blood and ovarian samples collected. Plasma steroid levels were determined and related to the developmental stage of the ovary. Ovaries of non-migrants contained oogonia and previtellogenic oocytes. Vitellogenic oocytes were never observed in these groups, but instead were very common among migrants (up to 88% of oocytes). Concentrations of both androgens (androstenedione (AD), testosterone (T)) and estradiol-17 (E2) were higher in migrants than in non-migrants. Among migrants, T levels were higher in shortfins (2.27 ± 0.14 ng ml–1) than in longfins (0.82 ± 0.10 ng ml–1), whereas E2 levels were higher in longfins (mean 2.46 ng ml–1) than in shortfins. Levels of sex steroids were generally low in non-migrants. In contrast, plasma levels of 17-hydroxyprogesterone were significantly higher in non-migrants than in migrants. Similarly, cortisol levels were higher in non-migrating than in migrating shortfinned, but not longfinned, females. 17,20-Dihydroxy-4-pregnen-3-one, the putative maturation-inducing steroid in anguillids, was near minimum-detectable levels for all animals examined. Surprisingly, very high levels of 11-ketotestosterone (KT) were found in migrants, averaging nearly 3 ng ml–1 in longfins and over 20 ng ml–1 in shortfins. The identity of KT and several 5-reduced androgens was confirmed using gas chromatography - mass spectrometry. The function of KT in females is not known, but we suggest that this steroid hormone may play a role in preparing maturing animals for their spawning migration.     

Effects of Dietary Recombinant Bovine Somatotropin Levels on Growth, Plasma Recombinant Bovine Somatotropin Concentrations, and Body Composition of Juvenile Korean Rockfish, Sebastes schlegeli

This experiment was conducted to study the effects of the graded recombinant bovine somatotropin (rBST) levels on growth, plasma rBST concentrations, and body composition of Korean rockfish, Sebastes schlegeli, and to estimate the optimum oral dosage of rBST. Seven experimental diets were formulated to be isonitrogenous and isocaloric and to contain 49.0% crude protein and 16.7 kJ available energy/g, with 0, 5, 10, 15, 20, 25, or 50 mg rBST/kg body weight (BW)/wk (rBST₀, rBST₅, rBST₁₀, rBST₁₅, rBST₂₀, rBST₂₅, and rBST₅₀, respectively). After the feeding trial, fish fed all the diets supplemented with rBST showed higher weight gain (WG), feed efficiency (FE), specific growth rate (SGR), and protein efficiency ratio (PER) than those fed the rBST₀ diet (P < 0.05). WG of fish fed rBST₁₅, rBST₂₀, rBST₂₅, and rBST₅₀ diets was significantly higher than that of fish fed rBST₀ and rBST₅ diets (P < 0.05); however, there were no significant differences among fish fed rBST₁₀, rBST₁₅, rBST₂₀, rBST₂₅, and rBST₅₀ diets. FE of fish fed rBST₁₅ and rBST₂₀ diets was significantly higher than that of fish fed rBST₀, rBST₅, rBST₁₀, and rBST₅₀ diets, and fish fed rBST₁₀, rBST₂₅, and rBST₅₀ diets had significantly higher FE than those fed rBST₀ and rBST₅ diets (P < 0.05). SGR of fish fed all the diets supplemented with rBST was significantly higher than that of fish fed rBST₀ diet (P < 0.05); however, there were no significant differences among fish fed all the diets supplemented with rBST. PER of fish fed rBST₁₅ and rBST₂₀ diets was significantly higher than that of fish fed rBST₀, rBST₅, and rBST₅₀ diets, and fish fed rBST₁₀, rBST₂₅, and rBST₅₀ diets had significantly higher PER than those fed rBST₀ and rBST₅ diets (P < 0.05). Whole‐body protein of fish fed rBST₁₅ diet was significantly higher than that of fish fed rBST₀, rBST₅, and rBST₁₀ diets (P < 0.05); however, there were no significant differences among fish fed rBST₁₅, rBST₂₀, rBST₂₅, and rBST₅₀ diets. Plasma rBST concentrations of fish fed all the diets began to rise at 3 h after oral administration of rBST; the maximum plasma rBST concentration peaked at 12 h and returned to the basal level at 24 h. Broken‐line model analyses of WG and FE were 12.8 and 13.2 mg rBST/kg BW/wk, respectively. These results indicated that the optimum oral dosage could be greater than 12.8 mg rBST/kg BW/wk but less than 13.2 mg rBST/kg BW/wk in juvenile Korean rockfish.     

The ninth component of complement and the pore-forming protein (perforin 1) from cytotoxic T cells: structural, immunological, and functional similarities

The ninth component of complement (C9) and the pore-forming protein (PFP or perforin) from cytotoxic T lymphocytes polymerize to tubular lesions having an internal diameter of 100 A and 160 A, respectively, when bound to lipid bilayers. Polymerized C9, assembled by slow spontaneous or rapid Zn2+-induced polymerization, and polyperforin, which is assembled only in the presence of Ca2+, constitute large aqueous pores that are stable, nonselective for solutes, and insensitive to changes of membrane potential. Monospecific polyclonal antibodies to purified C9 and PFP show cross-reactivity, suggesting structural homology between the two molecules. The structural and functional homologies between these two killer molecules imply an active role for pore formation during cell lysis.     

Deoxyribonucleic acid antibody: a method to detect its primary interaction with deoxyribonucleic acid

Antibody to DNA in human serums can be detected by the ammonium sulfate method. This sensitive and specific technique, which measures the primary interaction between DNA and antibody to DNA, is based on the observation that free DNA is soluble in 50-percent saturated ammonium sulfate whereas antibody-bound DNA is insoluble.