Identification of the coding region for the putidaredoxin reductase gene from the plasmid of Pseudomonas putida

The first 12 NH₂-terminal amino acids of the Pseudomonas putida putidaredoxin reductase were shown to be Met-Asn-Ala-Asn-Asp-Asn-Val-Val-Ile-Val-Gly-Thr. Comparison of these data with the DNA sequence of the BamHI-HindIII 197-base fragment derived from the PstI 2.2-kb fragment obtained from the P. putida plasmid showed that the putidaredoxin reductase gene was downstream from the cytochrome P-450 gene and the intergenic region had the 24-nucleotide sequence TAAACACATGGGAGTGCGTGCTAA. The Shine-Dalgarno sequence GGAG was detected in this region. The initiating triplet for the reductase gene was GTG, which normally codes for valine, but in the initiating codon position codes for methionine. From the amino acid sequence and X-ray data comparisons with other flavoproteins, what appears to be the AMP binding region of the FAD can be recognized in the NH₂-terminal portion of the reductase involving residues 5–35.This article was presented during the proceedings of the International Conference on Macromolecular Structure and Function, held at the National Defence Medical College, Tokorozawa, Japan, December 1985.     

A new fixed cryosection technique for the simultaneous immunocytochemical demonstration of T6 and S100 antigens

Summary A formalin—calcium fixation method of preparing cryosections is described, which allows demonstration of Langerhans' cells by S100 antigen staining on frozen sections. The number of Langerhans' cells given by T6 antigen staining is also higher in formalin—calcium fixed frozen sections than acetone fixed frozen sections. The preparation is suitable for dual demonstration of the two antigens on the same section enabling a more accurate numerical evaluation of Langerhans' cell populations in the normal cervical epithelium.     

Single channel kinetics of a glutamate receptor.

The glutamate receptor-channel of locust muscle membrane was studied using the patch-clamp technique. Muscles were pretreated with concanavalin A to block receptor-channel desensitization, thus facilitating analysis of receptor-channel gating kinetics. Single channel kinetics were analyzed to aid in identification of the molecular basis of channel gating. Channel dwell-time distributions and dwell-time autocorrelation functions were calculated from single channel data recorded in the precence of 10-4M glutamate. Analysis of the dwell time distributions in terms of mixtures of exponential functions revealed there to be at least three open states of the receptor-channel and at least four closed states. Autocorrelation function analysis showed there to be at least three pathways linking the open states with the closed. This results in a minimal scheme for gating of the glutamate receptor-channel, which is suggestive of allosteric models of receptor-channel gating.     

New and noteworthy South American species of Agalinis (Scrophulariaceae)

Agalinis bandeirensis is a Brazilian species distinguished by linear bracts, short pedicels, and villous stamens.Agalinis ramulifera, from southern Brazil, is distinguished by many, short, leafy branches and small flowers.Agalinis linarioides subsp.rojasi, from Paraguay, is distinguished by paniculate inflorescences, short calyx lobes, and broad corollas.Gerardia bangii, G. digitalis, andG. meyeniana are recognized as species ofAgalinis and appropriate transfers are made.     

A new microbioassay for the measurement of lactogenic hormones in human serum

The standard Nb2 assay for biologically active prolactin has been modified to allow a rapid convenient microbioassay without loss of specificity or accuracy. Lactogenic hormones specifically stimulate the replication of Nb2 node rat lymphoma cells in suspension culture and form the basis of a currently available bioassay to measure prolactin and growth hormone in human serum. A new microbioassay was developed using microtest plates enabling a large number of samples to be assayed simultaneously whilst maintaining the overall sensitivity of the bioassay for lactogenic hormones. Growth of the Nb2 node lymphoma cells, measured by a light scattering technique using optical density on a spectrophotometer, was shown to be closely correlated with the cell number determined on a Coulter counter. Addition of excess anti-human prolactin and anti-human growth hormone completely inhibited the growth stimulatory effects of both human prolactin and human growth hormone. This new microbioassay (BA) and conventional radioimmunoassay (RIA) were used to measure lactogenic hormones in 48 normal subjects. There was a close correlation between the results of both assays for each hormone studied in the control sera. The mean basal BA/RIA ratio was 1.5 (range 0.8-2.0) for prolactin, 0.7 (range 0-4.5) for growth hormone and 1.3 (range 0.5-1.9) for total lactogenic activity.     

New species of Aristolochia (Aristolochiaceae) from Peru

Aristolochia fosteri is a new species with unusual branched trichomes collected in Pasco near Oxapampa.Aristolochia hutchisonii is a prostrate species found in Amazonas and Cajamarca that is related toA. weberbaueri.Aristolochia barbouri is a narrow-leaved, herbaceous liana from Madre de Dios.     

Three new species of Elleanthus (Orchidaceae) from Central America

Elleanthus stolonifer andE. tillandsioides are new species in theE. poiformis complex of sectionChloidelyna.Elleanthus lentii is a new species in sectionStachydelyna. Elleanthus stolonifer is widespread in the mountains of Costa Rica and Panama;E. tillandsioides is found only in the lowland forests of southeastern Costa Rica;E. lentii is limited to the Cordillera de Guanacaste of Costa Rica.     

Two new species of Esterhazya (Scrophulariaceae) from Brazil

Barringer, Kerry (Department of Botany, Field Museum of Natural History, Chicago, IL 60605). Two new species of Esterhazya (Scrophulariaceae) from Brazil. Brittonia 37: 195–198. 1985.—Esterhazya petiolata is a distinctive species with ovate, petiolate leaves, spreading brances, and broadly tubular-campanulate flowers. It is known from the Serra Dourada of Goiás. Esterhazya eitenorum has narrow, lanceolate leaves, acute calyx lobes, and purple-pink flowers and is known from the planalto of Mt. Itatiaia.