Species Specificity of the Insect Prothoracicotropic Hormone (PITH): the Presence of Bombyx-and Samia-Specific PTTHs in the Brain of Bombyx mori

Crude extracts of Bombyx mori brains can provoke adult development when injected into brain-removed dormant pupae of Bombyx mori and Samia Cynthia ricini. From this fact the prothoracicotropic hormone (PTTH) of Bombyx has long been thought to be species-nonspecifically active on Samia. Chemical fractionation of Bombyx brain or head extracts by fractional precipitation with acetone, Sephadex G-50 gel-filtration, and DEAE-Sepharose CL-6B chromatography, however, separated the fractions which activated Bombyx brainless pupae from those which activated Samia. Those results reveal the existence of two species-specific PTTHs.     

Developmental morphology of the ovules of Amborella trichopoda (Amborellaceae) and Chloranthus serratus (Chloranthaceae)

The developmental morphology of the outer integument in the pendent orthotropous ovules of Amborella trichopoda (Amborellaceae) and Chloranthus serratus (Chloranthaceae) was studied. In both species the outer integument is semiannular at an early stage and becomes cup-shaped but dorsiventrally somewhat asymmetric at later stages. The outer integument, which is initiated first on the concave and lateral sides of the ovule, differs from that of the anatropous ovules of other basal families with the outer integument semiannular at an early stage or throughout development. The bilateral symmetry of the outer integument is shared by these orthotropous and anatropous ovules. The developmental pattern of the outer integument and ovule incurving characterize the ovule of the Amborellaceae and Chloranthaceae, which is not equivalent to typical orthotropous ovules of eudicots. A phylogenetic analysis of ovule characters in basal angiosperms suggests that anatropous ovules with cup-shaped outer integuments and orthotropous ovules were derived independently in several clades and that the ovules of Amborella and Chloranthus might also be derivative.     

CHANGES OF CHROMOSOMES DURING THE EARLY NEURAL DEVELOPMENT OF A JAPANESE NEWT, CYNOPS PYRRHOGASTER

The karyotype of Cynops pyrrhogaster was determined on the mitotic chromosomes in the presumptive neural area of an early gastrula. 24 chromosomes of a diploid set consisted of 8 metacentric and 4 submetacentric pairs. Individual chromosomes were identified on the basis of their morphology and characteristic C-binding patterns. Sex chromosomes were not identified. Total length of the haploid chromosome set in the presumptive neural area decreased remarkably from morulae to gastrulae, further continued to decrease up to neurulae and thereafter remained unchanged till tail-buds. Chromosome shortening occurring from morulae to gastrulae was accompanied with a prominent decrease in chromosome volume, keeping chromosome width constant. Shortening took place evenly along the longitudinal axis of a chromosome. When gastrulae and neurulae were compared concerning their positions of the appearance of the C-bands, the basic pattern remained unchanged. In certain chromosomes, the number of C-bands decreased as the result of their fusion, as gastrulae proceeded to neurulae.     

A Monoclonal Antibody that Binds Preferentially to Human Suppressor T Cells

A monoclonal antibody termed JM3-3-3A was produced by somatic cell hybridization. The reactivity was assessed by indirect immunofluorescence. JM3-3-3A was reactive with 41% human peripheral blood T cells and 48% non-T cells. Among various human lymphoblastoid cell lines (MOLT 4F, JM, and TALL-I), TALL-I was found not to be reactive with JM-13-3-3A. Human peripheral blood Tcells fractionated by JM3-3-3A-coated dish panning were submitted to functional studies. JM3-3-3A positive T cells responded to mitogens, concanavalin A and phytohemagglutinin-P much better than JM3-3-3A negative T cells in the presence or absence of adherent cells. JM3-3-3A positive T cells showed suppressor activity and JM3-3-3A negative T cells showed helper activity in pokeweed mitogen-induced Ig production. More than fifty percent of the JM3-3-3A positive T cells were reactive with OKT8 which binds to suppressor/ cytotoxic T cells, whereas 18% of JM3-3-3A negative T cells were reactive with OKTIl. In addition, immunoprecipitation experiments identified a protein with an approximate molecular weight of 43,000 as a cell surface antigen for JM3-3-3A. Thus, the reactivity of JM3-3-3A showed a wide distribution but human peripheral blood T cells could be dissected functionally by this antibody.     

Arsenic alters uptake and distribution of sulphur in Pteris vittata

Low‐molecular‐weight thiol (LMWT) synthesis has been reported to be directly induced by arsenic (As) in Pteris vittata, an As hyperaccumulator. Sulphur (S) is a critical component of LMWTs. Here, the effect of As treatment on the uptake and distribution of S in P. vittata was investigated. In P. vittata grown under low S conditions, the presence of As in the growth medium enhanced the uptake of SO₄^2?, which was used for LMWT synthesis in fronds. In contrast, As application did not affect SO₄^2? uptake in Nephrolepis exaltata, an As non‐hyperaccumulator. Moreover, the isotope microscope system revealed that S absorbed with As accumulated locally in a vacuole‐like organelle in epidermal cells, whereas S absorbed alone was distributed uniformly. These results suggest that S is involved in As transport and/or accumulation in P. vittata. X‐ray absorption near‐edge structure analysis revealed that the major As species in the fronds and roots of P. vittata were inorganic As(III) and As(V), respectively, and that As–LMWT complexes occurred as a minor species. Consequently, in case of As accumulation in P. vittata, S possibly acts as a temporary ligand for As in the form of LMWTs in intercellular and/or intracellular transport (e.g. vacuolar sequestration).