Analyses of muscular dystrophy and Con A deficiency traits in testcross progeny of chickens

Hereditary muscular dystrophic chickens of the Storrs strain possess two genetic disorders, muscular dystrophy (MD) and a deficient concanavalin A (Con A), a T-cell mitogen, mediated splenic lymphocyte blastogenic response. A possible amelioration of the MD phenotype in MD chickens expressing normal Con A was postulated on the basis of progeny segregating for these two traits in F2 genetic analyses. To test this possibility, testcross progeny were examined for segregation of MD and Con A deficiency traits, and for the degree of muscle destruction and Con A deficiency. The data show both traits to be inherited independently as autosomal recessive traits, and do not support any phenotypic modifications occurring in chickens expressing MD with normal Con A. In the testcross progeny, the Con A deficiency disorder is equally deficient in normal and MD progeny, and the degree of muscle destruction as measured by serum creatine phosphokinase levels is equally great in MD chickens with or without the Con A deficiency trait. The reduced numbers of MD chickens in the testcross progeny can be accounted for by chance and probably reflect losses during in ovo development.     

An amylase gene from Drosophila pseudoobscura is expressed in Escherichia coli. Functional selection and biochemical comparisons of the fly- and clone-produced amylases

An amylase gene from Drosophila pseudoobscura was isolated from a genomic library constructed in pBR322 and cloned in Escherichia coli by selecting for the ability of its product to hydrolyze starch, a carbon source not normally utilized by E. coli. Hybridization of pAMY17F to D. pseudoobscura polytene chromosomes shows a positive signal at the amylase pseudogene locus (bank 78, chromosome 3). The chimeric plasmid pAMY17F, has been altered in such a way as to increase amylase expression. Southern and Northern hybridizations to the cloned amylase DNA indicate that the source of the gene is from D. pseudoobscura. Biochemical properties such as pH optima, substrate specificities, electrophoretic analyses, inhibitor sensitivities, heat stabilities, temperature responsiveness and molecular weights indicate that the amylases produced by the fly and bacterial clone are similar and have similar properties. It appears that E. coli/pAMY17F is producing an amylase like that found in D. pseudoobscura.     

Molecular characterization of fetal antigens on red blood cells of chickens,Japanese quail,and quail-chicken hybrids

The molecular nature of chicken fetal antigen (CFA) and quail fetal antigen (QFA) was studied on embryonic red blood cells (RBCs) of the chicken, the Japanese quail, and the quail-chicken hybrid. Specific immunoprecipitation of radiolabeled membrane proteins followed by electrophoretic separation and autoradiography were used to identify the protein molecules carrying these fetal antigens. CFA was found on molecules of 24, 50, 88, 99, 130, 170, and 220 kd (kilodaltons) in the chicken and hybrid and on molecules of 24, 50, 99, and 170 kd in the Japanese quail. Similarly, quail fetal antigen was associated with 24-, 50-, 99-, and 170-kd molecules in the quail and hybrid and was not detected in the chicken. Partial proteolytic digestion of the 50- and 170-kd molecules isolated from RBCs of all sources showed remarkably similar peptide patterns. Likewise, two-dimensional separation of the CFA-positive and QFA-positive 50-kd molecules from quail RBCs revealed a similar pattern of at least nine isomorphic variants. Sequential depletions of quail embryonic RBC extracts with either anti-CFA or anti-QFA followed by immune precipitation with the reciprocal antiserum suggested that most of the cell surface proteins carrying QFA also have CFA on the same molecules. It is suggested that specific glycosylations of a variety of distinct molecular weight proteins determines the antigenic phenotype characterized as "fetal antigens."     

The relationship of maternal age and trisomy among trisomic spontaneous abortions

The relationship between maternal age and trisomy was examined by comparing mean ages of 954 trisomic spontaneous abortions with those of live births ascertained at the same study center. The overall mean for trisomy was highly significantly elevated over that of the newborns. The age effect was most pronounced for trisomies involving the small chromosomes, with trisomies 13, 14, 15, 16, 17, 18, 20, 21, and 22 all having significantly increased ages by comparison with the control population. However, the majority of trisomies involving large or medium-sized chromosomes also had elevated mean maternal ages, suggesting that most, if not all, human trisomies are associated with increasing age of the mother. Additional variation in the age effect was observed among trisomies involving similar-sized chromosomes, indicating that factors other than chromosome size also influence the relationship between increasing age and trisomy.     

Antineoplastic and antiherpetic activity of spermidine catecholamide iron chelators

A series of iron chelating agents including the bacterial siderophores, parabactin and bis-N1,N8(2,3 dihydroxybenzoyl )spermidine, and four related compounds were synthesized and tested biologically. They were found: (a) to inhibit growth of cultured L1210 leukemia cells at IC50 values of 2-14 microM, (b) to inhibit replication of the DNA virus, herpes simplex type I, in monkey kidney cells at IC50 values of 0.4 microM ( parabactin ) to 55 microM, and (c) to be inactive against the RNA virus, vesicular stomatitis, at concentrations up to 1 mM. All effects were fully preventable by exogenous Fe (III). The activities correlated generally with the iron formation constants (10(36) to 10(48) moles/1) and more specifically with the lipophilicity of the compounds. The data suggest inhibition of DNA (but not RNA) synthesis by interference with the iron-containing enzyme, ribonucleotide reductase.     

Startle-evoked changes in diaphragmatic activity during wakefulness and sleep

Tonic inhibition of some respiratory muscles occurs as part of the generalized muscle atonia of rapid-eye-movement sleep (REMS). A second type of inhibition of the diaphragm during REMS, fractionations, consists of brief pauses in the diaphragmatic electromyogram (DIA EMG) in association with phasic events. Because motor inhibition can occur as part of the startle response, and the brain is highly activated during REMS, we hypothesized that the neural basis of the fractionations might be activation of a startle network. To test this hypothesis, tone bursts (100 dB, 20-ms duration at 15-s intervals) were applied to cats at a fixed inspiratory level in the DIA moving average during REMS, non-rapid-eye-movement sleep (NREMS), and wakefulness. Parallel sham studies (no tone applied) were obtained for each state. The response of the DIA EMG was averaged over 100 ms by using the tone pulse as a trigger, and the following parameters of the DIA EMG were measured: latency to peak and/or nadir, increment or decrement in activity, and duration of peak and/or nadir. After a tone, all five animals studied displayed a profound suppression of DIA activity during REMS (latency to nadir 42.4 +/- 10.0 ms, duration of suppression 35.9 +/- 17.6 ms). Similarly, DIA activity was suppressed in all cats during NREMS (latency to nadir 40.9 +/- 13.3 ms, duration 23.9 +/- 13.4 ms). An excitatory response was observed in only two cats during NREMS and wakefulness. The similarity of startle-induced DIA EMG pauses to spontaneous fractionations of DIA activity during REMS suggests that the latter result from activation of a central startle system.     

The effect of long-distance running on plasma immunoreactive glucagon levels

Twelve highly conditioned long-distance runners were studied to determine the effects of marathon (42 km) and 10,000 m running on plasma immunoreactive glucagon (IRG), serum immunoreactive insulin (IRI), and serum glucose (G) levels. Blood samples were drawn just prior to and immediately upon completion of the run. Marathon running resulted in no significant change in G, IRI, or IRG levels. After running 10,000 m, plasma IRG levels did not change significantly, while IRI and G increased significantly. In evaluating the pooled data from both runs, a significant inverse correlation was observed between delta G and delta IRG. This relationship between delta G and delta IRG suggests that glucagon plays a role in maintaining normal blood glucose levels during strenuous exercise.     

The other ocean acidification problem: CO2 as a resource among competitors for ecosystem dominance

Predictions concerning the consequences of the oceanic uptake of increasing atmospheric carbon dioxide (CO₂) have been primarily occupied with the effects of ocean acidification on calcifying organisms, particularly those critical to the formation of habitats (e.g. coral reefs) or their maintenance (e.g. grazing echinoderms). This focus overlooks direct and indirect effects of CO₂ on non-calcareous taxa that play critical roles in ecosystem shifts (e.g. competitors). We present the model that future atmospheric [CO₂] may act as a resource for mat-forming algae, a diverse and widespread group known to reduce the resilience of kelp forests and coral reefs. We test this hypothesis by combining laboratory and field CO₂ experiments and data from ‘natural’ volcanic CO₂ vents. We show that mats have enhanced productivity in experiments and more expansive covers in situ under projected near-future CO₂ conditions both in temperate and tropical conditions. The benefits of CO₂ are likely to vary among species of producers, potentially leading to shifts in species dominance in a high CO₂ world. We explore how ocean acidification combines with other environmental changes across a number of scales, and raise awareness of CO₂ as a resource whose change in availability could have wide-ranging community consequences beyond its direct effects.