Collagenase Production by Nematode-Trapping Fungi

A number of species of nematode-trapping fungi, which capture and digest nematodes having keratin and collagen in their cuticles, were tested for the ability to produce extracellular collagenase and keratinase. Collagenase, which is active on ichthyocol, earthworm collagen, and procollagen from chicken embryo fibroblasts, was found in the growth medium of all tested species; keratinase was not found. The enzyme from Arthrobotrys amerospora was concentrated by precipitation with (NH₄)₂SO₄ and further purified by adsorption on collagen at 0°C. The collagenase was active over a pH range of 2.5 to 10.0. It was not inactivated by dialysis against ethylenediaminetetraacetic acid for 48 h or by the sulfhydryl group inhibitors N-ethylmaleimide and p-chloromercuribenzoate. The production of collagenase may aid the fungus to penetrate the cuticle of its prey.     

A convenient,rapid method for the resolution of enantiomeric amino acids using chiral phases on stainless-steel capillary gas chromatographic columns

An improved method is described for the resolution of enantiomeric isopropyl esters of N-trifluoroacetyl-α-amino acids of nonbasic amino acids using N-docosanoyl-l-valyl-t-butylamide and N-octadecanoyl-l-valyl-l-valine cyclohexyl ester as mixed chiral phases on 150-ft stainless-steel capillary columns. Enantiomers of Ala, Val, Ile, Leu, Ser, Thr, Asp, Met, Glu, and Phe are resolved in 105 min. This method avoids the fractionation problems and high costs encountered with the diastereometric method and difficulties and costs encountered in loading and maintaining glass capillary columns. It is particularly useful for studies involving a large number of resolutions as in a study of the kinetics of racemization of amino acids.     

Biological effects of anti-idiotypic antibodies on lymphocyte function: I. Analysis of the effects on B lymphocytes of combining site and framework-directed anti-T-15 idiotypic antibodies

Anti-idiotypic antibodies against TEPC-15 myeloma protein (BALB/c origin) were raised in allogeneic animals by immunization of A/J mice with the myeloma protein. The antibody activities were fractionated into two specificities by TEPC-15 immunoadsorbent affinity columns by elution with free hapten (phosphorylcholine, PC), followed by elution with acidic buffer (glycine- HCl, pH 2.3). Idiotype binding analysis indicated that the fraction eluted with hapten could be inhibited in its binding to TEPC-15 by free hapten (i.e., binding site-directed anti-idiotypic antibody), whereas the acid-eluted fraction could not (i.e., framework-directed anti-idiotypic antibody). When analyzed for their biological activities on PC-specific B lymphocytes producing T-15 idiotype-bearing antibodies, both anti-idiotypic antibody fractions had similar suppressive effects on the in vitro production of antiphosphorylcholine antibody in culture.     

The detection of Fc-IgA receptors on T and non-T,non-B acute leukemic lymphoblasts

Fc-IgA receptors have been described on purified human T-lymphocyte populations from normal individuals. More recently, non-T-cell subpopulations bearing Fc-IgA receptors have also been described. In this study, receptors for the Fc portion of IgA were detected on both T and non-T, non-B leukemic lymphoblasts from 15 patients with acute lymphoblastic leukemia (ALL). From 1.6 to 6.8% of the T lymphoblasts of 7 patients expressed Fc-IgA receptors and 0.5 to 3.9% of the non-T, non-B lymphoblasts of the remaining 8 patients expressed Fc-IgA receptors. The expression of IgA receptors on these cells may reflect the maturational state of these leukemic lymphoblasts. The detection of Fc-IgA receptors on leukemic lymphoblasts suggests that expression of these receptors on lymphoid cells represents an early maturational event.     

Systematic implications of flavonoid pigments in the fern genus hemionitis (adiantiaceae)

The closely related fern generaHemionitis L. andGymnopteris Bernhardi are separated primarily on differences in leaf architecture and venation. Studies indicate that these characters are highly variable and unreliably diagnostic. Further, the type species of the two genera readily hybridize with each other. Spore morphology, as exhibited by SEM, does not support the traditional alignment of the species in these two genera: some species ofHemionitis andGymnopteris have the same rugose to papillate spores, while other species from both genera possess crested spores. The flavonoid chemistry of these taxa coincides with spore type, i.e., taxa from both genera which possess crested spores produce kaempferol and quercetin 3-0-glycosides, while species with tuberculate spores produce only quercetin 3,4′-0-glycosides. The spore and chemical data suggest a realignment of these taxa within a single genus, which would avoid the rather tenuous dependence on a single vegetative character for generic distinctions.     

Structural data for the carbohydrate of ispaghula husk ex Plantago ovata forsk

The husk from the seeds of Plantago ovata Forsk yielded two fractions when exposed to mild aikali, namely, the mucilage polysaccharide (85%, apparently a single species) and the non-polysaccharide component (15%). Methylation analysis and partial hydrolysis with acid showed the mucilage polysaccharide to be a highly branched, acidic arabinoxylan, the xylan backbone having both (1→4) and (1→3) linkages. The majority of the residues in the xylan backbone are variously substituted at O-2 and O-3 with arabinose, xylose, and an aldobiouronic acid identified as 2-O-(galactopyranosyluronic acid)-rhamnose. A structure incorporating these features for the husk polysaccharide is proposed.     

Expression of I-region gene products on mouse tail epidermis cells.

Mouse epidermal cells express Ia antigens. Epidermal cells from C3H and B10. A mice express I-A and I-E region gene products. Products associated with I-B and I-J were not detectable. A weak reaction was seen with anti-I-C sera. Products of the I-A region appear to be preferentially expressed when compared to I-E-region gene products. Ten percent of epidermal cells possess IgG-specific Fc receptors and 15% of epidermal cells can phagocytize latex particles. Our studies suggest that Ia-positive epidermal cells in mice are not necessarily limited to Langerhans cells.     

The postembryonic cell lineages of the hermaphrodite and male gonads in Caenorhabditis elegans

The ancestry of the cells in the hermaphrodite and male gonadal somatic structures of C. elegans has been traced from the two gonadal somatic progenitor cells (Z1 and Z4) that are present in the newly hatched larvae of both sexes. The lineages of Z1 and Z4 are essentially invariant. In hermaphrodites, they give rise to a symmetrical group of structures consisting of 143 cells, and in males, they give rise to an asymmetrical group of structures consisting of 56 cells. The male gonad can be distinguished from the hermaphrodite gonad soon after the first division of Z1 and Z4. However, the development of Z1 and Z4 in hermaphrodites shares several features in common with their development in males suggesting that the two programs are controlled by similar mechanisms. In the hermaphrodite lineage, a variability in the positions of two cells is correlated with a variability in the lineages of four cells. This variability suggests that cell-cell interaction may play a more significant role in organisms that develop by invariant lineages than has hitherto been considered. None of the somatic structures (e.g., uterus, spermatheca, vas deferens) develops as a clone of a single cell. Instead, cells that arise early in the Z1–Z4 lineage generally contribute descendants to more than one structure, and individual structures consist of descendants of more than one lineage.     

Specificity of Insertion by the Translocatable Tetracycline-Resistance Element Tn10

Genetic analysis of 131 independent transpositions of the tetracycline-resistance element Tn10 from a single site in phage P22 into the histidine operon of Salmonella typhimurium reveals that Tn10 insertions are not randomly distributed along this chromosomal target. The insertions occur in 22 different "clusters"; insertions within each cluster are very tightly linked in recombination tests. Tn10 insertions are not evenly distributed among the identified clusters. The existence of these clusters suggests that this chromosomal target contains particular genetic signals that guide Tn10 to particular preferred positions for insertion. Insertions within each cluster occur in both orientations with roughly equal frequency.--The relationship among different insertions within each cluster has been examined. The resolution of genetic mapping places an upper limit of about 50 basepairs on the distance between different insertions within a cluster. Different insertions within a cluster usually have the same reversion frequency; however, heterogeneity in reversion frequency has been detected in at least two clusters. For most clusters, the available data are consistent with the simple possibility that all insertions within a cluster are at identical positions; however, the data do not exclude other possibilities.