Gravity and light control of the developmental polarity of regenerating protoplasts isolated from prothallial cells of the fern Ceratopteris richardii.

A procedure has been developed for isolating protoplasts from prothalli of Ceratopteris richardii which can be cultured and are capable of regeneration. Protoplasts were isolated from 2-week-old gametophytes in a medium containing wall-digesting enzymes in 0.5 M sucrose, followed by purification of the released protoplasts by floating them up into a 0.

Model experiment to study sonic boom propagation through turbulence. Part II. Effect of turbulence intensity and propagation distance through turbulence.

A model experiment was reported to be successful in simulating the propagation of sonic booms through a turbulent atmosphere [B. Lipkens and D. T.

Influence of gravity and light on the developmental polarity of Ceratopteris richardii fern spores.

The polarity of germinating single-celled spores of the fern Ceratopteris richardii Brogn. is influenced by gravity during a time period prior to the first cellular division designated a "polarity-determination window". After this window closes, control of polarity is seen in the downward (with respect to gravity) migration of the nucleus along the proximal face of the spore and the subsequent downward growth of the primary rhizoid.

Comparison of Sindbis virus-induced pathology in mosquito and vertebrate cell cultures.

We have compared Sindbis virus-induced cytopathology in vertebrate and mosquito (Aedes albopictus) cell cultures. It has been shown that vertebrate cells undergo apoptosis when infected by Sindbis virus and this was confirmed here using hamster cells (BHK). The occurrence of cell death in Sindbis virus-infected A.

Identification of nonprotein amino acids from cycad seeds as N-ethoxycarbonyl ethyl ester derivatives by positive chemical-ionization gas chromatography-mass spectrometry.

Nonprotein amino acids from nine species of cycad seeds were analyzed as N-ethoxycarbonyl ethyl ester (ECEE) derivatives by positive chemical-ionization gas chromatography-mass spectrometry. Based on the retention times and mass spectrometry analyses, 12 nonprotein amino acids were identified in these seeds. In addition to the excitatory and putative neurotoxin beta-N-methylamino-L-alanine (BMAA), the known neurotoxin beta-N-oxalylamino-L-alanine (BOAA) was detected from the seeds of Macrozamia moorei and M.

Superinfection exclusion of alphaviruses in three mosquito cell lines persistently infected with Sindbis virus.

Three Aedes albopictus (mosquito) cell lines persistently infected with Sindbis virus excluded the replication of both homologous (various strains of Sindbis) and heterologous (Aura, Semliki Forest, and Ross River) alphaviruses. In contrast, an unrelated flavivirus, yellow fever virus, replicated equally well in uninfected and persistently infected cells of each line. Sindbis virus and Semliki Forest virus are among the most distantly related alphaviruses, and our results thus indicate that mosquito cells persistently infected with Sindbis virus are broadly able to exclude other alphaviruses but that exclusion is restricted to members of the alphavirus genus.

Clerodane diterpenoids, long chain esters of coumaric acid and other compounds from Baccharis myrsinites.

A new clerodane diterpenoid and two new long chain esters of trans- and cis-coumaric acid, in addition to known triterpenoids and one known clerodane diterpenoid, have been isolated and characterized from Baccharis myrsinites. The structures were determined by spectroscopic techniques.

Nonprotein amino acids from Cycas revoluta.

Two nonprotein amino acids, cycasindene and cycasthioamide, along with eight known nonprotein amino acids, were isolated from the seeds of Cycas revoluta Thunb. The structures of cycasindene and cycasthioamide were elucidated as 3-[3'-amino-indenyl-2]-alanine (1) and N-[glycinyl-alaninyl-11-thio]-5-one-pipecolic acid (2) by chemical and spectral methods.

Bioeffects of positive and negative acoustic pressures in vivo.

In water, the inertial collapse of a bubble is more violent after expansion by a negative acoustic pressure pulse than when directly compressed by a positive pulse of equal amplitude and duration. In tissues, gas bodies may be limited in their ability to expand and, therefore, the relatively strong effectiveness of negative pressure excursions may be tempered. To determine the relative effectiveness of positive and negative pressure pulses in vivo, the mortality rate of Drosophila larvae was determined as a function of exposure to microsecond length, nearly unipolar, positive and negative pressure pulses.

Costs of diabetes in Texas, 1992.

Objective: To estimate direct and indirect costs of diabetes in Texas in 1992.

Research Design And Methods: For most direct medical costs, we relied on third party and provider billing databases, including Medicare, Medicaid, VA facilities, public hospitals, and others. The researchers identified people with diabetes in the respective databases, located all records of their care, and sorted records as clearly, probably, or probably not attributable to diabetes on the basis of principal diagnoses.

Partial purification and characterization of a type 1 protein phosphatase in purified nuclei of pea plumules.

We report the isolation and characterization of a protein Ser/Thr phosphatase from highly purified pea nuclei. In subnuclear fractions, more than 75% of Ser/Thr protein phosphatase activity was associated with the chromatin fraction, whereas the other 25% was in the nuclear membrane/nucleoplasmic fraction when phosphorylase a was used as a substrate. The enzyme was purified approx.

Mutations in the endo domain of Sindbis virus glycoprotein E2 block phosphorylation, reorientation of the endo domain, and nucleocapsid binding.

Exposure of the carboxyl terminus (endo domain) of Sindbis virus membrane glycoprotein E2 to the cell cytoplasm is critical for the interaction of the nucleocapsid with viral envelope proteins in modified cell membranes. We have shown that the endo domain of PE2/E2 is initially translocated into membranes of the endoplasmic reticulum and subsequently drawn back into the cell cytoplasm during virus assembly. We suggested that phosphorylation of PE2/E2 might be responsible for the reorganization of the PE2/E2 carboxyl terminus.

An unusual cycloartane triterpenoid from Cimicifuga foetida.

A new cycloartane triterpenoid glycoside has been isolated from the rhizomes of Cimicifuge foetida L. The spectroscopic characteristics of the new compound are different from previously described cycloartane triterpenoids because of the loss of the 24-isopropyl group as well as the presence of a 11 beta-OH group. Based on spectroscopic evidence, including a series of 2D-NMR analyses, the structure of the new triterpene is assigned as 24-des-isopropyl-7-ene-23-one-9,19; 16,24-dicycloart-3 beta,11 beta,16 alpha,24 alpha-tetraol 3-O-beta-D-xylopryanoside, named here as neocimiside.

Nonprotein amino acids from seeds of Cycas circinalis and Phaseolus vulgaris.

Our chemical studies on Cycas circinalis seeds from Guam has provided two new nonprotein amino acids, N-(3'-one-5'-methyl)-hexylalanine and leucine betaine. N-methylisoleucine, previously reported as a component of naturally occurring peptides, has been isolated as a free amino acid from the seeds of Phaseolus vulgaris (pinto bean), together with S-methylcysteine, pipecolic acid and a dipeptide, gamma-glutamyl-leucine.

Assembly of the Sindbis virus spike protein complex.

The Sindbis virus glycoproteins E1 and E2 are organized into 80 trimers of heterodimers within the virus envelope. Using pulse-chase protocols and chemical crosslinkers, we have found that E1 and E2 precursor, PE2, rapidly assemble into heterodimers and then into trimers of heterodimers after translocation into the endoplasmic reticulum. E1 folds into its mature conformation within the endoplasmic reticulum via at least three intermediates differing in the configurations of their disulfide bonds.

Transcription of tufA and other chloroplast-encoded genes is controlled by a circadian clock in Chlamydomonas.

Levels of mRNA for the chloroplast-encoded elongation factor Tu (tufA) showed a dramatic daily oscillation in the green alga Chlamydomonas reinhardtii, peaking once each day in the early light period. The oscillation of tufA mRNA levels continued in cells shifted to continuous light or continuous dark for at least 2-3 days. Run-off transcription analyses showed that the rate of tufA transcription also peaked early in the light period and, moreover, that this transcriptional oscillation continued in cells shifted to continuous conditions.

Events in the endoplasmic reticulum abrogate the temperature sensitivity of Sindbis virus mutant ts23.

Temperature-sensitive mutations in proteins produced at or heated to a nonpermissive temperature render the proteins defective in some aspect of their maturation into functional entities. The characterization of temperature-sensitive mutations in model proteins, such as virus membrane proteins, has allowed the elucidation of critical events in the maturation of virus membranes as well as in the intracellular folding, processing, and transport of membrane proteins in general. We have used a transport-defective, temperature-sensitive mutant of Sindbis virus, ts23, which has two amino acid changes in the envelope protein E1, to further examine requirements placed upon the glycoproteins for their export to the plasma membrane.

End-to-end annealing of plant microtubules by the p86 subunit of eukaryotic initiation factor-(iso)4F.

The p86 subunit of eukaryotic initiation factor-(iso)4F from wheat germ exhibits saturable and substoichiometric binding to maize microtubules, induces microtubule bundling in vitro, and is colocalized or closely associated with cortical microtubule bundles in maize root cells, indicating its function as a microtubule-associated protein (MAP). The effects of p86 on the growth of short, taxol-stabilized maize microtubules were investigated. Pure microtubules underwent a gradual length redistribution, an increase in mean length, and a decrease in number concentration consistent with an end-to-end annealing mechanism of microtubule growth.

Assessing potential targets of calcium action in light-modulated gravitropism.

Light, through the mediation of the pigment phytochrome, modulates the gravitropic response of the shoots and roots of many plants. The transduction of both light and gravity stimuli appears to involve Ca(2+)-regulated steps, one or more of which may represent points of intersection between the two transduction chains. To be confident that Ca2+ plays a critical role in stimulus-response coupling for gravitropism, it will be important to identify specific targets of Ca2+ action whose function can be clearly linked to the regulation of growth.

Replication and tissue tropism of the alphavirus Sindbis in the mosquito Aedes albopictus.

We have examined the replication and tissue distribution of the alphavirus Sindbis in the mosquito Aedes albopictus. Parenteral inoculation of virus resulted in an acute infection accompanied by rapid virus replication and a persistent infection, during which total virus production was reduced. Acute and persistent phase virus RNA synthesis, virus production, and organ-specific distribution of infection were determined over an 18-day incubation period.

Identification of a second cellulose synthase gene (acsAII) in Acetobacter xylinum.

A second cellulose synthase gene (acsAII) coding for a 175-kDa polypeptide that is similar in size and sequence to the acsAB gene product has been identified in Acetobacter xylinum AY201. Evidence for the presence of this gene was obtained during analysis of A. xylinum mutants in which the acsAB gene was disrupted (I.

Enzymes of B-ring-deoxy flavonoid biosynthesis in elicited cell cultures of "old man" cactus (Cephalocereus senilis).

Elicited cell cultures of the cactus Cephalocereus senilis produce a group of flavonoids with unsubstituted B-rings, including an aurone which represents a new class of phytoalexin. Preliminary enzymological studies indicated that the chalcone synthase (CHS) and chalcone isomerase (CHI) from cultures of C. senilis were active with cinnamoyl-CoA and 2',4',6'-trihydroxychalcone, respectively, probable intermediates for synthesis of flavonoids with unsubstituted B-rings.

The atpF group-II intron-containing gene from spinach chloroplasts is not spliced in transgenic Chlamydomonas chloroplasts.

In order to determine whether the group-II trans-splicing machinery of the chloroplast of Chlamydomonas reinhardtii can splice a heterologous group-II cis intron, the atpF gene of spinach was transferred into the chloroplast genome of C. reinhardtii using the atpX expression vector. The atpF gene contains a group-II intron which, like other higher plant chloroplast introns, does not self-splice in vitro.

GC-MS analysis of nonprotein amino acids in Gymnocladus dioicus as N(O,S)-isobutyloxycarbonyl silyl derivatives.

Two different derivatives of novel nonprotein amino acids in Gymnocladus dioicus seeds are prepared for gas chromatographic (GC) and mass spectrometric (MS) analysis. The interfering components in a water extract of the seeds are removed by picric acid treatment and multistep washing with organic solvents followed by N(O,S)-isobutyloxycarbonylation combined with solid-phase extraction. The resulting N(O,S)-isobutyloxycarbonyl (isoBOC) amino acids are then converted to either tert-butyldimethylsilyl (TBDMS) or trimethylsilyl (TMS) derivatives, which are analyzed by dual capillary column GC and GC-MS.