The Human Mast Cell Chymase Gene (CMA1): Mapping to the Cathepsin G/Granzyme Gene Cluster and Lineage-Restricted Expression

Genes encoding T-cell-receptor α/δ chains, neutrophil cathepsin G, and lymphocyte CGL/granzymes are closely linked on chromosomal band 14q11.2. The current work identifies the human mast cell chymase gene (CMA1) as the fourth protease in this cluster and maps the gene to within 150 kb of the cathepsin G gene. The gene order is centromere-T cell receptor α/δ-CGL-1/granzyme B-CGL-2/granzyme H-cathepsin G-chymase. Chymase and cathepsin G genes are shown to be cotranscribed in the human mast cell line HMC-1 and in U-937 cells. Other cells transcribe cathepsin G or CGL/granzyme genes, but not chymase genes, suggesting a capacity for independent regulation. Comparison of the 5′ flank of the chymase gene with those of cathepsin G and CGL/granzymes reveals little overall homology. Only short regions of the 5′ flanks of the human and murine chymase genes sequenced to date are similar, suggesting that they are more distantly related than human and rodent CGL-1/granzyme B, the flanks of which are highly homologous. The expression patterns and clustering of genes provide possible clues to the presence of locus control regions that orchestrate lineage-restricted expression of leukocyte and mast cell proteases.     

Photo-induction of electrical current with the cyanobacteriumAgmenellum quadruplicatum PR-6

We investigated the possibility of eliciting a measurable photoinduced electrical current from the cyanobacteriumAgmenellum quadruplicatum PR-6 (Synechococcus PCC 7002). This proved virtually impossible for intact cells. However, treated PR-6 cells fixed in an alginate matrix on tin oxide as the active electrode in a three electrode electrochemical cell gave rise to a significant light response. Cell treatments involving toluene, chloroform or detergents were effective and gave current responses up to 250 nA. Drying the cyanobacterial matrix increased the current yield at least fifty-fold. These effects were observed for light wavelengths > 650 nm and were not influenced by inhibitors or enhancers of photosynthesis nor by sustained argon bubbling of the electrolyte.French pressure cell lysates facilitated distinction between two light induced current components. Lysates prepared without CaCl₂ gave current induction kinetics that were indistinguishable from those on chemically treated cells i.e. slowly rising to a stable maximum in 10–15 min. When CaCl₂ was present during lysis, a rapidly induced (<1 s) unstable component was observed. Toluenization of PR-6 either prior to or post lysing abolished the CaCl₂ related effect. CaCl₂ had no effect on current induction in strain PR-6008, which lacked the and subunits of phycocyanin and exhibited slow current induction kinetics.The observed effects are interpreted as responses of components of the photosystems of PR-6 rather than in terms of an integrated photosynthetic process.     

PHYLOGENY OF THE ULVOPHYCEAE (CHLOROPHYTA): CLADISTIC ANALYSIS OF NUCLEAR-ENCODED rRNA SEQUENCE DATA1

Cladistic analysis of nuclear-encoded rRNA sequence data provided us with the basis for some new hypotheses of relationships within the green algal class Ulvophyceae. The orders Ulotrichales and Ulvales are separated from the clade formed by the remaining orders of siphonous and siphonocladous Ulvophyceae (Caulerpales, Siphonocladales /Cladophorales [S/C] complex, and the Dasycladales), by the Chlorophyceae and Pleurastrophyceae. Our results suggest that the Ulvophyceae is not a monophyletic group. Examination of inter- and intra-ordinal relationships within the siphonous and siphonocladous ulvophycean algae revealed that Cladophora, Chaetomorpha, Anadyomene, Microdictyon, Cladophoropsis and Dictyosphaeria form a clade. Thus the hypothesis, based on ultrastructural features, that the Siphonocladales and Cladophorales are closely related is supported. Also, the Caulerpales is a monophyletic group with two lineages; Caulerpa, Halimeda, and Udotea comprise one, and Bryopsis and Codium comprise the other. The Dasycladales (Cymopolia and Batophora) also forms a clade, but this clade is not inferred to be the sister group to the S/C complex as has been proposed. Instead, it is either the sister taxon to the Caulerpales or basal to the Caulerpales and S/C clade The Trentepohliales is also included at the base of the siphonous and siphonocladous ulvophycean clade. The Pleurastrophyceae, which, like the Ulvophyceae, posses a counter-clockwise arrangement of flagellar basal bodies, are more closely related to the Chlorophyceae than to the Ulvophyceae based on rRNA sequences. Thus, the arrangement of basal bodies does not diagnose a monophyletic group. Previously reported hypotheses of phylogenetic relationships of ulvophycean algae were tested. In each case, additional evolutionary steps were required to obtain the proposed relationships. Relationships of ulvophycean algae to other classes of green algae are discussed.     

Structure,Ultrastructure and Function of the Neural Gland Complex of Ascidia interrupta (Chordata,Ascidiacea): Clarification of Hypotheses Regarding the Evolution of the Vertebrate Anterior Pituitary

Abstract The neural gland complex of Ascidia interrupta consists of three parts: dorsal tubercle, ciliated duct, and neural gland. The dorsal tubercle protrudes above the pharyngeal lining and bears a ciliated funnel. The funnel opens into a ciliated duct which opens into the neural gland, a blind sac in a blood sinus below the brain. Funnel and duct cells are joined by adhaerens junctions and, apically, by putative tight junctions. The neural gland wall is a loose, irregular, non-ciliated epithelium of phagocytes. Adhaerens, but not tight, junctions join the cells. Secretory cells were not observed. Tracers delivered onto the dorsal tubercle and dissolved in seawater around undissected animals are transported unidirectionally inward into the neural gland. The continuous ciliary incurrent moves the tracers across the wall of the neural gland and into the pharyngeal blood vessels. Small particulates and large macromolecules, however, are removed from the water stream by endocytosis on neural gland cells. Large particulates delivered onto the dorsal tubercle do not enter the system but rather are rejected by cilia on the surface of the tubercle. The neural gland complex is interpreted as an organ of blood volume regulation that consists of a pump (cilia) and coarse (tubercle) and fine (gland) filters. Analogous and homologous systems are discussed.     

PATTERNS OF PLANT ONTOGENY THAT MAY INFLUENCE GENOMIC STASIS

It is an axiom in biology that genes control the ontogeny and ultimately the final form of an organism. In plants a given morphological form can often arise through more than one ontogenetic pattern of cell divisions. Different ontogenetic patterns have different properties with regard to the final age in cell divisions of the initials in the meristems for a given morphological form. If mutation per genome per cell division is an important biological metric, then since the age of a cell in cell divisions is a function of ontogeny, the cellular ontogeny will influence the degree of mutation-loading in meristematic initials. Thus, ontogeny and form may affect the genes (by promoting or lessening genomic stasis) as well as, of course, being determined by the genes. This paper explores mathematically the relationship between different patterns of cell division and mutation-loading.     

EMBRYOLOGY OF CALYPSO BULBOSA. I. OVULE DEVELOPMENT

Calypso bulbosa is a terrestrial orchid that grows in north temperate regions. Like many orchids, the Calypso has ovules that are not fully developed at anthesis. After pollination, the ovule primordia divide several times to produce a nucellar filament which consists of five to six cells. The subterminal cell of the nucellar filament enlarges to become the archesporial cell. Through further enlargement and elongation, the archesporial cell becomes the megasporocyte. An unequal dyad results from the first meiotic division. A triad of one active chalazal megaspore and two inactive micropylar megaspores are the end products of meiotic division. Callose is present in the cell wall of the megaspore destined to degenerate. In the mature embryo sac the number of nuclei is reduced to six when the chalazal nuclei fail to divide after the first mitotic division. The chalazal nuclei join the polar nucleus and the male nucleus near the center of the embryo sac subsequent to fertilization.     

RESTRICTION FRAGMENT ANALYSIS OF CHLOROPLAST DNA AND THE SYSTEMATICS OF VIGUIERA AND RELATED GENERA (ASTERACEAE: HELIANTHEAE)

Phylogenetic relationships among 31 species representing variously Helianthus, Helianthopsis, Heliomeris, Simsia, Viguiera, and Tithonia were assessed by chloroplast DNA restriction site mapping. A total of 147 mutations including 92 informative ones was detected using 16 restriction enzymes, with an estimated sequence divergence within the group of 1.4%. Parsimony analysis produced a single most parsimonious tree with a length of 161 steps and a consistency index of 0.91. Statistically significant clades, as assessed by the bootstrap method, correspond to a number of taxa recognized previously, including Helianthus (3 species), Helianthopsis (5 species), and several groups within Viguiera, including sect. Maculatae (4 species), the Baja California group (6 species), sect. Paradosa (2 species) and V. dentata (3 samples). However, species of Viguiera collectively form a highly paraphyletic group relative to species of other genera. Helianthus and Helianthopsis were separated into different clades, supporting their recent segregation. Placement of H. porteri in Helianthus rather than Heliomeris was confirmed; the single sample of the latter genus was most similar to the Baja California group of Viguiera. An expected relationship between Simsia (2 species) and one member of Viguiera ser. Grammatoglossae was confirmed (although not with two other putatively related members of Viguiera) and an unexpected relationship between Simsia and Tithonia was suggested. The presence of Mexican taxa as the more basal groups in the tree points toward a possible Mexican origin for Viguiera and related genera. A molecular clock hypothesis is rejected in many pairwise comparisons involving woody taxa with herbaceous ones, although it could not be rejected in most pairwise comparisons involving taxa of similar habit.     

Contribution of pilA to Competitive Colonization of the Squid Euprymna scolopes by Vibrio fischeri

Vibrio fischeri colonizes the squid Euprymna scolopes in a mutualistic symbiosis. Hatchling squid lack these bacterial symbionts, and V. fischeri strains must compete to occupy this privileged niche. We cloned a V. fischeri gene, designated pilA, that contributes to colonization competitiveness and encodes a protein similar to type IV-A pilins. Unlike its closest known relatives, Vibrio cholerae mshA and vcfA, pilA is monocistronic and not clustered with genes associated with pilin export or assembly. Using wild-type strain ES114 as the parent, we generated an in-frame pilA deletion mutant, as well as pilA mutants marked with a kanamycin resistance gene. In mixed inocula, marked mutants were repeatedly outcompeted by ES114 (P < 0.05) but not by an unmarked pilA mutant, for squid colonization. In contrast, the ratio of mutant to ES114 CFUs did not change during 70 generations of coculturing. The competitive defect of pilA mutants ranged from 1.7- to 10-fold and was more pronounced when inocula were within the range estimated for V. fischeri populations in Hawaiian seawater (200 to 2,000 cells/ml) than when higher densities were used. ES114 also outcompeted a pilA mutant by an average of twofold at lower inoculum densities, when only a fraction of the squid became infected, most by only one strain. V. fischeri strain ET101, which was isolated from Euprymna tasmanica and is outcompeted by ES114, lacks pilA; however, 11 other diverse V. fischeri isolates apparently possess pilA. The competitive defect of pilA mutants suggests that cell surface molecules may play important roles in the initiation of beneficial symbioses in which animals must acquire symbionts from a mixed community of environmental bacteria.