Synthesis of alpha and gamma interferons by a human cutaneous lymphoma with helper T-cell phenotype

A cloned human cutaneous lymphoma Hut102-B2 with helper T-cell phenotype (Leu1⁺, Leu2a^?, Leu3a⁺) was found to produce substantial quantities of interferon (IFN) on induction with the phorbol ester, 12-O-tetradecanoylphorbol-13-acetate (TPA). Whereas only trace amounts of IFN were secreted by Hut102-B2 cells spontaneously, up to 8000 laboratory units/ ml of IFN were synthesized under the optimal conditions of TPA induction. Characterization studies including neutralization by specific antisera to IFNs and determination of the activities in human and bovine cells disclosed that the IFN produced by Hut102-B2 cells exposed to TPA was a mixture of immune IFN (IFN-γ) and leukocyte IFN (IFN-α) made in approximately equal amounts in terms of antiviral activity.     

Genetic and developmental evidence for a repressed genital primordium in Drosophila melanogaster

Agametic, a maternal-effect mutation, causes the absence of germ cells in approximately 40% of the gonads of flies derived from homozygous females. The nature of the deficiency in the eggs produced by these flies was examined. Ultrastructural abnormalities were seen in the polar granules of some eggs shortly after fertilization. Although a normal number of pole cells form, some are abnormal with degenerating polar granules and nuclear bodies and they contain myeloid bodies. The pole cells reach the gonads and at 14 hr of development all the gonads contain germ cells. However, in 40% of the gonads the germ cells become necrotic and disappear. Thus, the source of agametic gonads in the adult is embryonic death of pole cells in some gonads. To test whether this gonadal death is an autonomous deficiency of the mutant pole cells, mosaic pole cell populations were produced by reciprocal pole cell transplantation. In both types of transplants, the mutant pole cells died autonomously. In eight instances gonads containing only donor pole cells were obtained. Since mutant pole cells die when wild-type pole cells normally begin dividing, we suggest that the lesion affects the ability of these mutant pole cells to reenter the cell cycle.     

Developmental appearance of myosin heavy and light chain isoforms in vivo and in vitro in chicken skeletal muscle

Three myosin heavy chain isoforms with unique peptide maps appear sequentially in the development of the chicken pectoralis major muscle. An embryonic isoform is expressed early and throughout development in the embryo. A second isoform appears just after hatching and predominates by 10 days ex ovo. A third isoform, indistinguishable from adult myosin heavy chain, predominates by 8 weeks after hatching. This sequence of myosin isoform change does not, however, appear during myogenesis in vitro. In cultures prepared from embryonic myoblasts only embryonic myosin heavy chain is expressed. This is true even in cultures maintained for 30 days. Myosin light chain expression also changes in vivo with a progressive increase in fast light chain 3 accumulation. In vitro, however, this shift to increasing fast light chain 3 accumulation does not occur. The results indicate that the myosin heavy chain and light chain pattern observed in vitro is identical to that of the embryonic muscle and that the conditions necessary for the shift in expression to a more mature myosin phenotype are not present in myogenic cultures. These cultures are therefore potentially of great value in probing further the neural and humoral determinants of muscle fiber maturation and growth.     

The apical lamina of the sea urchin embryo: Major glycoproteins associated with the hyaline layer

The hyaline layer (HL) surrounding the sea urchin blastula appears to dissolve in 1 M glycine. However, after this treatment, there persists over the surfaces of the blastomeres a layer of material, referred to here as the apical lamina (AL), that sloughs off as an adhesive convoluted bag upon gradual dissociation of the embryo. Isolated hyaline layers, referred to as HL-AL complexes, were analyzed by urea-SDS-polyacrylamide gel electrophoresis. A major protein of the HL-AL complex, hyalin, bands or precipitates in the stacking gel. Two other major proteins, both strongly PAS positive, migrate with apparent molecular weights of 175K and 145K daltons. As with intact embryos, the glycine wash removes the hyalin protein from the isolated HL-AL complex, leaving the undissolved AL which consists primarily of the 175K- and 145K-dalton proteins. The embryo's own perivitelline-localized cortical granule peroxidase heavily radioiodinates the proteins of the HL-AL complex, further verifying their apical, extracellular location. Unlike hyalin, the AL proteins do not precipitate with calcium ions. Compared to the entire HL-AL complex, the AL contains a greater percentage of carbohydrate. No sialic acid is associated with the HL-AL complex, but the AL contains some sulfate. In contrast to a published report based on ultrastructural staining, no biochemical evidence was found in this study for the presence of collagen or significant glycosaminoglycan within the HL-AL complex. No developmental differences were observed in AL proteins from 1-hr-old embryos compared to those from blastulae. However, there is evidence suggesting heterogeneity and developmental differences in hyalin. The possible organization of hyalin and the AL proteins into separate layers surrounding the embryo is discussed. The influence of the AL proteins in morphogenesis and cell adhesion is considered, and hypothetical roles attributed to the HL and hyalin are critically questioned.     

Further Studies on the Role of Polyploidy in the Evolution of Meloidogyne

Two tetraploid isolates of Meloidogyne hapla, 86P and E289P, with haploid chromosome numbers of 34 and 28, respectively, were studied cytogenetically and biologically in relation to the diploid populations, 86-Va (n = 17) and E289-Taiwan (n = 14), from which they had been originally isolated. Both isolates were quite stable, converting to diploidy at the low rate of about 2.5%. The tetraploid isolate 86P maintained itself in competition with its diploid counterpart in mixed cultures, although an initial frequency of 50% polyploidy was reduced to about 9% at the end of the sixth generation. Both tetraploid isolates could maintain themselves in greenhouse cultures without artificial selection for at least 2 years. Crosses between diploid females and tetraploid males resulted in a few triploid females that produced mostly nonviable eggs, suggesting partial reproductive isolation between the two ploidy forms. Ten generations of propagation of only polyploid females of isolate 86P that were associated with males failed to yield an obligatorily amphimictic isolate that would not convert at all to diploidy. If one accepts a previous assumption that the present day amphimictic root-knot nematodes are tetraploids derived from diploid ancestors, results of the present study are not inconsistent with an evolutionary trend toward an even higher level of ploidy in Meloidogyne, presumably octaploidy.     

Seasonal and spatial patterns of S,Ca, and N dynamics of a Northern Hardwood forest ecosystem

Seasonal dynamics of S, Ca and N were examined at the Huntington Forest, a northern hardwood ecosystem in the central Adirondacks of New York for a period of 34 months (1985–1988). Solute concentrations and fluxes in bulk precipitation, throughfall (TF) and leachates from the forest floor, E horizon and B horizon were quantified. Both above and below-ground elemental fluxes mediated by vegetation (e.g. uptake, litter inputs, and fine roots production) were also determined. The roles of abiotic and biotic processes were ascertained based on both changes in solute concentrations through the strata of the ecosystem as well as differences between dormant and growing seasons. Concentrations of SO₄ ²⁻, NO₃ ⁻, NH₄ ⁺ and Ca²⁺ were greater in TF than precipitation. Forest floor leachates had greater concentrations of SO₄ ²⁻, NO₃ ⁻ + NH₄ ⁺ and Ca²⁺ (9, 6 and 77 μeq L⁻¹, respectively) than TF. There were differences in concentrations of ions in leachates from the forest floor between the dormant and growing seasons presumably due to vegetation uptake and microbial immobilization. Concentrations and fluxes of NO₃ ⁻ and NH; were greatest in early spring followed by a rapid decline which coincided with a demand for N by vegetation in late spring. Vegetation uptake (44.7 kg N ha⁻¹ yr⁻¹ ) could account for the low leaching rates of N0₃ ⁻. Within the mineral soil, changes with soil depth and the absence of seasonal patterns suggest that cation exchange (Ca⁺) or anion sorption (SO₄ ²⁻) are primarily responsible for regulating solute concentrations. The increase in SO₄ ²⁻ concentration after leachates passed through the mineral soil may be attributed to desorption of sulfate that was adsorbed during an earlier period when SO₄ ²⁻ concentrations would have been greater due to elevated S inputs.     

A METHOD FOR ESTIMATING MASS OF LARGE PINNIPEDS

Fifty-two male elephant seals were weighed and photographed at Año Nuevo State Reserve, California, to establish a predictive relationship between photographically measured morphological variables (length, side area, and girth area) and body mass. Regression of mass on these variables revealed that side area, roughly equivalent to a longitudinal cross-section, was the most useful single variable for predicting mass, and that adding the other two variables to side area slightly improved the accuracy of the photogrammetric technique. Curvilinear regressions based on a power model provided the best predictive relationships. This technique may prove useful for estimating body mass of other pinnipeds.     

Isozyme Diversity is Low in Paeonia californica (Paeoniaceae)

Abstract The California Peony ( Paeonia californica ), a regional endemic and outcrossing species, is almost completely monomorphic for 23 isozyme loci. The level of genetic diversity in the California Peony is similar to that of narrow endemics and/or self-fertilizing species. This paradoxical result may be explained by either of two hypotheses: 1) low initial polymorphism of the ancestral genome, or 2) population bottle neck.