Schistosoma mansoni polypeptides immunogenic in mice vaccinated with radiation-attenuated cercariae

We compared the humoral immune response of mice protected against Schistosoma mansoni by vaccination with radiation-attenuated cercariae to that of patently infected mice, and we identified antigens that elicit a greater, or unique, immune response in the vaccinated mice. These comparisons were based upon radioimmunoprecipitations and immunodepletion of [35S]methionine-labeled schistosomular and adult worm polypeptides, followed by one- and two-dimensional polyacrylamide gel analyses. The humoral responses of patently infected mice and of mice vaccinated once were remarkably similar and were directed against schistosome glycoproteins ranging in molecular size from greater than 300 to less than 10 kDa. Exposing mice to a second vaccination resulted in a marked change in the immune response, to one predominantly directed toward high molecular size glycoproteins. Sequential immunodepletion techniques identified five schistosomular and seven adult worm antigens that showed a greater or unique immunogenicity in vaccinated mice as compared with patently infected mice. These adult worm antigens were purified by preparative sequential immunoaffinity chromatography and used to prepare a polyclonal antiserum, anti-irradiated vaccine. This antiserum bound to the surface of live newly transformed and lung-stage schistosomula, as assessed by immunofluorescence assays, and was reactive with a number of 125I-labeled schistosomular surface polypeptides, including a doublet of 150 kDa that was also recognized by sera of vaccinated mice but not by sera of patently infected mice.     

A general pre-steady-state solution to complex kinetic mechanisms

We have developed a general method for solving transient kinetic equations using Laplace transforms. Laplace transforms can be used to transform systems of differential equations that describe pre-steady-state kinetics to systems of linear algebraic equations. The general form of the pre-steady-state solution is (formula; see text) where I(t) is the time dependence of the physically observed property of the system, n is the number of intermediates, lambda i are the observed rate constants (reciprocals of the relaxation times), t is time, and Ii are the amplitude coefficients associated with each observed rate constant. We have written a program in compiled BASIC to run on a personal computer to evaluate Ii and lambda i. The program will evaluate the rate constants and coefficients of a mechanism with eight intermediates and seven relaxation times in 4 s on an 8-MHz PC-XT equipped with a math coprocessor. The most complex mechanism that we have solved, a mechanism containing 20 intermediates and 19 relaxation times, required approximately 5 min. We believe that this method will be useful to evaluate the differences in transient properties of complex biochemical mechanisms.     

Structural organization of the beta-globin locus of B-haplotype sheep

Goats and some sheep synthesize a juvenile hemoglobin, Hb C (alpha 2 beta C2), at birth and produce this hemoglobin exclusively during severe anemia. Sheep that synthesize this juvenile hemoglobin are of the A haplotype. Other sheep, belonging to a separate group, the B haplotype, do not synthesize hemoglobin C and during anemia continue to produce their adult hemoglobin. To understand the basis for this difference we have determined the structural organization of the beta- globin locus of B-type sheep by constructing and isolating overlapping genomic clones. These clones have allowed us to establish the linkage map 5' epsilon I-epsilon II-psi beta I-beta B-epsilon III-epsilon IV- psi beta II-beta F3' in this haplotype. Thus, B sheep lack four genes, including the BC gene, and have only eight genes, compared with the 12 found in the goat globin locus. The goat beta-globin locus is as follows: 5' epsilon I-epsilon II-psi beta X-beta C-epsilon III-epsilon IV-psi beta Z-beta A-epsilon V-epsilon VI-psi beta Y-beta F3'. Southern blot analysis of A-type sheep reveals that these animals have a beta- globin locus similar to that of goat, i.e., 12 globin genes. Thus, the beta-globin locus of B-haplotype sheep resembles that of cows and may have retained the duplicated locus of the ancestor of cows and sheep. Alternatively, the B-sheep locus arrangement may be the result of a deletion of a four-gene set from the triplicated locus.      

In vitro culture of Trichogramma pretiosum on an artificial medium

The composition of an artificial medium and environmental conditions are described for the in vitro rearing of the egg parasite Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae). The medium was composed of defined amounts of protein, carbohydrates, lipid, salts, and vitamins, but also contained up to 40% insect hemolymph. The hemolymph was necessary to induce pupation. T. pretiosum eggs were obtained by dissection of Heliothis virescens (F.) (Lepidoptera: Noctuidae) eggs. In vitro reared T. pretiosum were similar in size to H. virescens reared T. pretiosum, and females were fecund.

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Résumé Les oeufs de Trichogramma pretiosum ont été obtenus par dissection d'oeufs d'Heliothis virescens. T. pretiosum Riley (Hymenoptère, Trichogrammatidae) a été élevé avec succès sur un substrat synthétique. Outre des quantités définies de protéines, glucides, lipides, éléments minéraux et vitamines, la ration contenait aussi jusqu'à 40% d'hémolymphe de Manduca sexta. L'hémolymphe était nécessaire pour induire la nymphose. En plus de la nourriture, les conditions d'environnement sont apparues extrêmement importantes pour élever T. pretiosum dans des conditions satisfaisantes. Le contrôle de l'humidité relative, en particulier, était le facteur le plus important. Les adultes produits au cours de cette étude étaient d'apparence normale; ils se sont accouplés sans problèmes, les femelles étaient fécondes et leur taille ne différait pas de celle d'individus élevés sur H. virescens.

     

ACTH 1-24-induced potentiation of norepinephrine contractile responses in aortic strips from spontaneously hypertensive (SH) and normotensive (WKY) rats

Norepinephrine (NE)-induced contractile responses were less in aortic strips from SH compared to WKY rats. ACTH 1-24 potentiated NE responses in both SH and WKY aortic strips. This effect was more potent in SH aortic strips. NE-induced contractions in SH aortic strips were less sensitive to changes in external Ca2+ levels than were those of WKY aortic strips. ACTH 1-24 did not potentiate NE responses under low external Ca2+ conditions in SH aortic strips or under high external Ca2+ conditions in WKY aortic strips. The greater sensitivity of NE responses following ACTH 1-24 in SH aortic strips may imply that this peptide is modulating a mechanism related to an impaired contractility and that Ca2+ plays a key role in the observed effects.     

ACTH/MSH(4-10) peptide increases postnatal metabolic activity of EDL muscle following early prenatal administration

ACTH/MSH(4-10) (10 micrograms/kg/b.i.d.; IP), administered to pregnant Sprague-Dawley rats during gestational days (GD) 3 to 12, significantly increased the metabolic activity of extensor digitorum longus (EDL) muscle at postnatal day 14. ACTH/MSH peptide, administered from day of birth to postnatal day 13, had no effect on EDL muscle metabolic activity using the 2,3,5-triphenyltetrazolium chloride indicator. By postnatal day 30, no differences were seen between the early prenatally treated group and saline controls. These results confirm our previous electrophysiological studies that showed that early prenatal ACTH/MSH(4-10) administration accelerates EDL muscle maturation.     

Intensive Linkage Mapping in a Wasp (Bracon Hebetor) and a Mosquito (Aedes Aegypti) with Single-Strand Conformation Polymorphism Analysis of Random Amplified Polymorphic DNA Markers

The use of random amplified polymorphic DNA from the polymerase chain reaction (RAPD-PCR) allows efficient construction of saturated linkage maps. However, when analyzed by agarose gel electrophoresis, most RAPD-PCR markers segregate as dominant alleles, reducing the amount of linkage information obtained. We describe the use of single strand conformation polymorphism (SSCP) analysis of RAPD markers to generate linkage maps in a haplodiploid parasitic wasp Bracon (Habrobracon) hebetor and a diploid mosquito, Aedes aegypti. RAPD-SSCP analysis revealed segregation of codominant alleles at markers that appeared to segregate as dominant (band presence/band absence) markers or appeared invariant on agarose gels. Our SSCP protocol uses silver staining to detect DNA fractionated on large thin polyacrylamide gels and reveals more polymorphic markers than agarose gel electrophoresis. In B. hebetor, 79 markers were mapped with 12 RAPD primers in six weeks; in A. aegypti, 94 markers were mapped with 10 RAPD primers in five weeks. Forty-five percent of markers segregated as codominant loci in B. hebetor, while 11% segregated as codominant loci in A. aegypti. SSCP analysis of RAPD-PCR markers offers a rapid and inexpensive means of constructing intensive linkage maps of many species.