A radioimmunoassay for the initial metabolites of the F prostaglandins

Antibodies to the F metabolite 9α, 11α-dihydro-15-keto-prostanoic acid (I), produced in the rabbit, do not cross react with any of the primary PGs. There is a 50% cross reaction with the metabolite 9α, 11α-dihydroxy-15-keto-prost-5-enoic acid (III), and a 23% cross reaction with 9α,11α,15-trihydroxy prostanoic acid (F₀α). No cross reactivity resulted with this antiserum when tested against 9α,11α,15-trihydroxy-5-enoic acid (VII) or with 9α,11α-dihydroxy-15-ketoprost-5,13-dienoic acid (VIII). Utilizing this antibody in a radioimmunoassay, some preliminary data are presented on levels of these F metabolites (I and III) for human adult male samples of plasma, urine and seminal plasma.     

Characterization of surface glycoproteins on Schistosoma mansoni adult worms by lectin affinity chromatography

Adult Schistosoma mansoni were radiolabeled by direct radioiodination using the Bolton-Hunter reagent or by metabolic labeling using radioactive hexose precursors. Tegumental material was extracted by freeze-thaw or by incubation in the non-ionic detergent Nonidet P-40, then applied to chromatography columns containing the following immobilized lectins: Con A, lentil lectin, wheat germ agglutinin, soybean agglutinin and the agglutinins from Ricinus communis and Helix pomatia. SDS-PAGE analysis of the sugar eluates from these columns revealed the presence of 15 glycoproteins with apparent molecular weights greater than or equal to 300,000, 215,000, 168,000, 152,000, 134,000, 122,000, 108,000, 83,000, 58,000, 53,000, 46,000, 41,000, 34,000, 30,000 and 23,500. Many of the glycoproteins reacted with more than one lectin. Information about carbohydrate content and lectin binding provides a preliminary characterization of the tegumental glycoprotein antigens of adult worms.     

The distribution of quinacrine on chromosomes as determined by X-ray microanalysis

The distribution of quinacrine in relation to Q-banding on CHO chromosomes has been investigated using X-ray microanalysis. Technical problems involved in this type of experiment were studied in detail. It was necessary to use a solution of quinacrine acetate in acetic acid to ensure that the only chlorine detectable in quinacrine-stained chromosomes was in the quinacrine molecule. Electron irradiation during analysis rapidly destroys quinacrine fluorescence, but the chlorine is not lost from the chromosomes, and there are several reasons for supposing that a reliable distribution of quinacrine on the chromosome can be obtained by the method. — Small variations along the chromosome in the amounts of chlorine (representing quinacrine) and of phosphorus (mainly DNA) occur. The distribution patterns for chlorine and phosphorus show a good resemblance to each other for each homologous chromosome; quinacrine fluorescence patterns (Q-bands) do not resemble chlorine distribution patterns, however. The results of this study therefore support the view that Q-bands result from the differential quenching of fluorescence along chromosomes to which the quinacrine is essentially uniformly bound, and do not reflect differential binding of quinacrine along the chromosome.With an Appendix by A. D. Carothers and D. Rutovitz     

The formation of bilirubin and p-nitrophenyl glucuronides by rabbit liver

1. Glucuronide formation of bilirubin and p-nitrophenol in vitro with excess of UDP-glucuronic acid by UDP-glucuronyltransferase from livers of young and adult rabbits was studied. 2. The development of UDP-glucuronyltransferase for the two substrates followed a markedly different pattern during maturation of young rabbits, p-nitrophenol-conjugation ability being much higher at birth than that for bilirubin. 3. Mg(2+) increased bilirubin conjugation, but inhibited p-nitrophenyl glucuronide formation. 4. p-Nitrophenol acted as a potent non-competitive inhibitor for bilirubin conjugation but bilirubin did not affect p-nitrophenyl glucuronidation. 5. The enzyme for bilirubin conjugation was inactivated at pH9 during treatment with snake venom, whereas in the same preparation the activity of the corresponding enzyme for p-nitrophenol was enhanced. In addition, some solubilization of the latter enzyme could be achieved by this method. 6. The possibility of the existence of more than one enzyme system for the formation of O-glucuronides is discussed.     

Correlation of pachytene chromomeres and metaphase bands of human chromosomes, and distinctive properties of telomeric regions

By means of double staining with DAPI and chromomycin A3, we show that the chromomeres of human pachytene chromosomes are generally DAPI positive and chromomycin negative, like the G- or Q-bands of mitotic chromosomes. Thus we have demonstrated, using an objective technique not based on morphological comparisons, that chromomeres and G-bands are equivalent. However, terminal chromomeres and the ends of mitotic chromosomes, as well as a few other sites, are chromomycin positive and DAPI negative. The ends of human chromosomes appear, therefore, to contain a distinctive class of GC-rich DNA.     

The electrostatic fields in the active-site clefts of actinidin and papain.

The active sites of actinidin (EC 3.4.22.14) and papain (EC 3.4.22.2) display different reactivity characteristics to probes targeted at the active-site cysteine residue despite the close structural similarity of their active sites. The calculated electrostatic fields in the active-site clefts of actinidin and papain differ significantly and may explain the reactivity characteristics of these enzymes. Calculation of electrostatic potential also focuses attention on the electrostatic properties that govern formation of the active-site thiolate-imidazolium ion-pair. These calculations will guide the modification of the pH-activity profile of the cysteine proteinases by site-directed mutagenesis.     

Distribution, seasonal use, and predation of incubation mounds of Orange-footed Scrubfowl on Komodo Island, Indonesia

ABSTRACT.   Megapodes are unique in using only heat from the environment, rather than body heat, to incubate their eggs as well as the precocious independence of their chicks on hatching. Of 22 recognized species of megapodes, 9 are listed as threatened due to factors including habitat loss and fragmentation, and predation on eggs and chicks. Orange-footed Scrubfowl ( Megapodius reinwardt ) are conspicuous components of the Oriental/Austral avifauna that inhabit the monsoon forests of the Lesser Sunda chain of islands in Indonesia. We examined the abundance, patterns of distribution, physical characteristics, seasonal activity, and predation risk of incubation mounds of Orange-footed Scrubfowl on Komodo Island in eastern Indonesia. We surveyed 13 valleys on Komodo Island from April 2002 to January 2005 and located 113 tended and 107 untended incubation mounds. Densities of scrubfowl mounds in our study were similar to that reported by investigators during the 1970s, suggesting little change in the scrubfowl population since then. Most scrubfowl mounds were on sandy or loamy soils in open monsoon forest with little overhead shade, and placement of mounds in such areas may ensure adequate temperatures for egg incubation. Although some mounds were tended during all months, mound use peaked during the late wet season in March. During the dry season (April–November), only a few mounds were tended. Komodo dragons ( Varanus komodoensis ) and wild pigs ( Sus scrofa ) were the primary predators of scrubfowl eggs, with no indication of egg predation by humans. The valley with the largest number of untended mounds in our study also had the largest number of active Komodo dragon nests. This suggests an effect of Komodo dragons on scrubfowl numbers, but additional study is needed.