SMITHSONIELLA GEN. NOV., A POSSIBLE EVOLUTIONARY LINK BETWEEN THE MULTICELLULAR AND SIPHONOUS HABITS IN THE ULVOPHYCEAE,CHLOROPHYTA

A low relief, green turf-forming alga of a heterotrichous habit was discovered in the coral reef microcosm, Museum of Natural History, Smithsonian Institution. Erect filaments bore lateral, specialized sporangia and together with basal filaments possessed septal plugs between adjacent cells, grossly similar to the “pit connections” of red algae. Data are presented which: 1) establish the identity of our plant with a plant recently described as Pilinia earleae Gallagher et Humm from the Florida Gulf coast; 2) support our establishment of the new genus Smithsoniella and our transfer of P. earleae to this new taxon. Additional data on pigmentation and cytology are related to the fine structure of other selected green algae to develop and test three hypotheses, viz. Smithsoniella earleae represents either: 1) a symbiotic association between a green and a red alga; 2) an alga which belongs to either the Ulotrichales, Chaetophorales or the Chroolepidales; or 3) an alga representing an evolutionary link between filamentous forms of the Ulvophyceae and members of the coenocytic siphonalean complex (e.g., Codiales or Caulerpales) of the Chlorophyta. Data refute hypotheses 1 and 2 but do lend support to the third hypothesis.     

Parallel usage of medicinal plants by africans and their caribbean descendants

Cultivated plants are cited by anthropologists as important indicators of man’s past. Medicinal species, to a large extent, have been overlooked even though in some cases these plants represent some of the social and cultural traditions of the people who use them. A number of cultivated plants have been traced from the Old World to the New World and are generally believed to have been carried there by European explorers and early settlers. However, some evidence has been accumulating to indicate that there may have been contacts other than by European colonists. One trade route that has been neglected is that of the slave trade from west Africa to the Caribbean. Three plant species,Citrus aurantifolia, Ricinus communis andAbrus precatorius, may exemplify the role and use of this route. They also indicate the migration and assimilation of west African Fulani, Hausa, and Mandingo cultures and Obeah religion into Caribbean society.     

Purification and characterization of a brain-specific protein kinase C substrate, neurogranin (p17). Identification of a consensus amino acid sequence between neurogranin and neuromodulin (GAP43) that corresponds to the protein kinase C phosphorylation site and the calmodulin-binding domain.

Neurogranin, formerly designated p17 (Baudier, J., Bronner, C., Kligman, D., and Cole, R. D.) (1989) J. Biol. Chem. 264, 1824-1828), a brain-specific in vitro substrate for protein kinase C (PKC), has been purified to homogeneity from bovine forebrain. The purified protein has a molecular mass of 7837.1 +/- 0.5 Da, determined by electrospray mass spectrometry. In the absence of reducing agent, dimers and higher oligomers accumulated. On sodium dodecyl sulfate-polyacrylamide gels the protein monomer migrated abnormally with an apparent molecular mass of 15,000-19,000 Da, depending on the percentage of polyacrylamide. The native protein is blocked at its amino terminus. The majority of the primary amino acid sequence was determined following proteolytic and chemical fragmentation. A comparison of the amino acid sequence of neurogranin with that of the brain-specific PKC substrate neuromodulin, revealed a strikingly conserved amino acid sequence AA(X)KIQA-SFRGH(X)(X)RKK(X)K. The two proteins are not related over the rest of their sequences. Neurogranin was shown to be phosphorylated in hippocampal slices incubated with 32Pi and phorbol esters stimulated neurogranin phosphorylation, suggesting that neurogranin is likely to be an in vivo substrate for PKC. In vitro phosphorylation of neurogranin by PKC produced a shift of the isoelectric point of the protein (pI 5.6) to a more acidic value (pI 5.4). Tryptic digestion of the phosphorylated protein yielded a single phosphopeptide having the sequence IQASFR, where the serine residue is the phosphorylated amino acid. This phosphopeptide is part of the conserved sequence shared with neuromodulin and also corresponds to the PKC phosphorylation site on neuromodulin (Apel, E. D., Byford, M. F., Au, D., Walsh, K. A., and Storm, D. R. (1990) Biochemistry 29, 2330-2335). Evidence was obtained suggesting that neurogranin binds to calmodulin in the absence of Ca2+, a feature that also characterizes neuromodulin. We propose that the amino acid sequence shared by neurogranin and neuromodulin reflects a functional relationship between these two proteins and that the consensus sequence represents a conserved PKC phosphorylation site and a calmodulin binding domain that characterizes a class of brain-specific PKC substrates.     

The lysis of Gram-negative Alcaligenes eutrophus by enzymes from Cytophaga

Summary The use of Cytophaga lysing enzymes was investigated for the liberation of poly--hydroxybutyrate (PHB) granules from the Gram-negative bacterium Alcaligenes eutrophus. Complete cell lysis was approached within a 60 minute period. Contrary to previous findings for the lysis of Gram-negative bacteria, prior removal of the outer membrane was not essential for enzymic lysis. The destabilisation of the outer membrane by the removal of divalent cations resulted in no significant improvement in the disruption process.     

How do floater male eastern bluebirds benefit by filling vacancies on territories where females already have young?

When male eastern bluebirds (Sialia sialis) are killed or deserttheir mates, replacement males usually take over the territory.We captured 25 eastern bluebird males and held them in captivityto study the behavior of replacement males and their responseto young already present in the nest. Of 17 replacement males,most courted the females, and 23% of experimental females renested,a proportion not different from that of control females. Noreplacement males were infanticidal, and none fully adoptedthe young. Replacement males spent significantly less time onthe territory and defended it significantly less than controlmales. We discuss breeding options available to a floater maleeastern bluebird and conclude that (1) floater male bluebirdsthat fill territory vacancies benefit by gaining breeding opportunitiesin the current breeding season, and (2) indifference to theyoung is the least costly option for replacement male easternbluebirds.     

Factors affecting recurrent shoot multiplication in in vitro cultures of 17- to 20-year-old douglas fir trees

Summary The effects of sucrose concentration, addition of ammonium nitrate, and exposure to N⁶-benzyl-adenine (BA) on multiplication potential with shoots derived from shoot cultures of 17- to 20-yr-old Douglas fir trees [Pseudotsuga menziesii (Mirb.) Franco] were compared. Each of these conditions, when compared independently, affected recurrent shoot multiplication and influenced shoot development, as measured by the abundance of shoot apices. Sucrose concentration was influential, the use of 25 g · liter⁻¹ providing twice the multiplication obtained with 20 g · liter⁻¹, and 14 × that obtained with the 30 g · liter⁻¹ concentration routinely used (tree 11). Ammonium nitrate usage also improved multiplication, a 2.5 times improvement being obtained after incorporation of 100 mg · liter⁻¹ NH₄NO₃ into the medium (tree 33). Shoot cultures were responsive but relatively sensitive to addition of BA, the best improvement in multiplication (5 times) being obtained with brief exposures to 3 mg · liter⁻¹ BA (tree 11). Although shoot cultures were responsive to the conditions investigated, differences in shoot multiplication and development were not displayed for several weeks. It was not possible therefore to repeat all the treatments with more than one genotype; however, when this was possible a genotype-dependent variation in response was evident.     

Substrate specificity of the protease that processes human interleukin-1 beta

The substrate specificity of the protease which generates mature human interleukin-1 beta (IL-1 beta) from pro-interleukin-1 beta was investigated using synthetic peptide substrates and recombinant pro-IL-1 beta. The requirement of an L-aspartate in the P-1 position was confirmed together with the need for a small hydrophobic residue in the P-1' position (Gly or Ala). It was shown that the enzyme can tolerate conservative substitutions in the P-2 and P-2' positions. We found little difference in the enzyme's ability to cleave denatured and native pro-IL-1 beta, indicating that tertiary structure recognition is not involved in binding. The enzyme did, however, require a peptide of more than six amino acids for cleavage to occur. These results conclusively demonstrate the unusual specificity of this protease.     

Identification of a novel amino acid alpha-tyrosine 93 within the cholinergic ligands-binding sites of the acetylcholine receptor by photoaffinity labeling. Additional evidence for a three-loop model of the cholinergic ligands-binding sites

The native, membrane-bound, acetylcholine receptor from Torpedo marmorata was photolabeled by the competitive antagonist p-[3H]dimethylaminobenzene-diazonium fluoroborate (DDF) in the presence of the noncompetitive blocker phencyclidine and under energy transfer conditions. The isolated alpha-subunits were treated with cyanogen bromide and fractionation of the resulting fragments yielded three radiolabeled peptides, at the level of which, incorporation of [3H]DDF (i) was equally inhibited by the agonist carbamoylcholine and the competitive antagonist alpha-bungarotoxin and (ii) was insensitive to "scavenging" reagents. Subfragmentation of cyanogen bromide peptide III with omicron-iodosobenzoic acid or trypsin and sequence analysis of the fragments led to the identification of a novel amino acid alpha-Tyr-93 (and possibly Trp-86) as labeled by [3H]DDF in a carbamoylcholine-sensitive manner. alpha-Tyr-93 is conserved in the muscle and neuronal alpha-subunits but not in the other subunits of muscle receptor. This result provides evidence for a site involving at least a third loop of the alpha-subunit amino-terminal hydrophilic domain, in addition to the ones previously identified (Dennis, M., Giraudat, J., Kotzyba-Hibert, F., Goeldner, M., Hirth, C., Chang, J. Y., Lazure, C., Chretien, M., and Changeux, J. P. (1988) Biochemistry 27, 2346-2357). Possible contribution of tyrosine side-chains to the complexation of the quaternary ammonium group of cholinergic ligands is discussed.     

The treatment of cluster headache with relaxation and thermal biofeedback

Eleven patients with episodic cluster headache were assessed and offered a treatment program consisting of 8 weeks of training in abbreviated progressive relaxation followed by 12 sessions of thermal biofeedback. Four dropped out before treatment began. Of the seven who completed the full treatment regimen, three (27% of initial sample) reported some degree of improvement when their next cluster bout occurred. In no one was the disorder eliminated.This research was supported by a grant from the National Institute of Neurological and Communicative Disorders and Stroke, NS-15235.     

The induction of sensitivity to gibberellin in aleurone tissue of developing wheat grains

Aleurone tissue from undried immature developing wheat grains (Triticum aestivum L. cv. Sappo), normally insensitive to gibberellic acid, can be made to respond to the hormone by a series of temperature treatments. Incubation of the de-embryoed grains at temperatures above 27° C for at least 8 h causes the tissue to become sensitive. Prolonged incubation at temperatures below 27° C does not effect a change in sensitivity. In addition to the requirement for exposure to an elevated temperature for a period of several hours the tissue must also subsequently be subjected to a period at a lower temperature for just a few seconds for the response to be observed. Once sensitized, the tissue remains responsive to gibberellic acid for substantial periods of time. Exposure of the tissue to temperatures which induce sensitivity to gibberellic acid also results in an increased leakage of amino acids. It is suggested that the increase in sensitivity to gibberellin requires two separate processes to take place. One could be a homeoviscous adaptation of the cell membranes in response to elevated temperature, the other a subsequent, permanent change in conformation of membrane components.