A physical domain of herpes simplex virus ICP8 is expressed and active in Escherichia coli.

In this report, we describe a series of procedures to assay the function of fusion genes in Escherichia coli and the specific application to the carboxy-terminal third of the herpes simplex virus type 1 (HSV-1) DNA-binding protein ICP8. E. coli cells containing the cloned HSV-1 BamHI G fragment with the HSV-1 BamHI-G-V site, map unit 0.388, nearest the tet promoter in pBR322 synthesized an active product containing a portion of ICP8. The new product induced phenotypic alterations in recipient hosts that were measurable and stable yet limited to the stability of the plasmid. The corresponding cloned DNA from the characterized HSV-1 DNA-binding protein mutant tsHA1 exhibited a predictable temperature-sensitive phenotype. Screening procedures based on the loss of induction of the parental plasmid-induced phenotype in E. coli cells allowed us to select additional mutations. One of these, which conferred a phenotype different from that of tsHA1, was transferred to the viral genome by marker transfer techniques. We suggest that any mutant could be isolated in any sequence, provided that the wild-type coding sequences induce alterations in E. coli cells. The observed alterations should have relevance in determining the mode of action of the protein in its normal environment.     

Antagonism by theophylline of respiratory inhibition induced by adenosine

The effects on respiration of an analogue of adenosine, L-2-N6-(phenylisopropyl)adenosine (PIA), and of the methylxanthine, theophylline, were determined in 19 vagotomized glomectomized cats whose end-tidal PCO2 was kept constant by means of a servo-controlled ventilator. Integrated phrenic nerve activity was used to represent respiratory output. Our results show that PIA, whether given systemically or into the third cerebral ventricle, depressed respiration. Systemically administered theophylline stimulated respiration. Theophylline given intravenously, or into the third ventricle not only reversed the depressive effects of previously administered PIA but caused further increases of respiration above the control level. Prior systemic administration of theophylline blocked both respiratory and hypotensive effects of subsequently administered PIA. Effects of either agent on medullary extracellular fluid pH did not explain the results. We conclude that the adenosine analogue PIA, acts to inhibit neurons in the brain that are involved in the control of respiration and that its effects are blocked by theophylline. We suggest that adenosine acts as a tonic modulator of respiration and that theophylline stimulates breathing by competitive antagonism of adenosine at neuronal receptor sites.     

Circumsporozoite protein of Plasmodium berghei: gene cloning and identification of the immunodominant epitopes.

The gene encoding the circumsporozoite (CS) protein of the rodent malaria parasite Plasmodium berghei was cloned and characterized. A cDNA library made from P. berghei sporozoite RNA was screened with a monoclonal antibody for expression of CS protein epitopes. The resulting cDNA clone was used to isolate the CS protein gene from a lambda library containing parasite blood-stage DNA. The CS protein gene contains a central region encoding two types of tandemly repeated amino acid units, flanked by nonrepeated regions encoding amino- and carboxy-terminal signal and anchorlike sequences, respectively. One of the central repeated amino acid unit types contains the immunodominant epitopes.     

PATTERNS OF REPRODUCTION IN THREE SANDY BEACH WHELKS OF THE GENUS BULLIA GRIFFITH

The breeding cycles of two species of sandy beach whelk (Bulliadigitalis and B. pura) are presented and compared with a thirdspecies (B. rhodostoma). In all three species, egg maturationand copulation occur in spring while summer marks the depositionand spawning of egg capsules. B. digitalis and B. pura migrateoffshore to lay their eggs, the juveniles of both species restrictingthemselves to beyond the breaker zone. Newly hatched snailsof B. rhodostoma appear in the intertidal towards late summer.The discovery of a penis-like structure on females of B. rhodostomais investigated. The pseudopenis was also found on B. pura butnever on B. digitalis. The possibility of a sex-change was eliminatedon the histological investigation of the gonads of a range ofsnails and the examination of sex-ratios over a period of fivemonths. General trends in reproductive behaviour are also discussed. (Received 18 March 1984;     

Nucleic acid relationships among Acholeplasma species.

3H-labeled Acholeplasma DNA probes were generated in vitro by the nick-translation method and used to determine the nucleotide sequence homology among the type strains of the eight currently recognized species of Acholeplasma. Very little nucleotide sequence homology (less than or equal to 18%) was found among the eight species, with heteroduplexes showing at least 12% or more mismatching as determined by thermal elution midpoints. The small amount of nucleotide sequence homology among the eight species indicates that these species are quite distinct and are not closely related to each other genomically.     

Four new species of Cayaponia (Cucurbitaceae) from Brazil and Bolivia

Four new species ofCayaponia are described and illustrated: three from Brazil (C. cogniauxiana, C. nitida andC. rugosa) and one from Brazil and Bolivia (C. ferruginea).     

Polyphyly of Asian Tree Toads,Genus Pedostibes Günther, 1876 (Anura: Bufonidae), and the Description of a New Genus from Southeast Asia

The Asian Tree Toad genus Pedostibes, as currently understood, exhibits a conspicuously disjunct distribution, posing several immediate questions relating to the biogeography and taxonomy of this poorly known group. The type species, P. tuberculosus and P. kempi, are known only from India, whereas P. hosii, P. rugosus, and P. everetti are restricted to Southeast Asia. Several studies have shown that these allopatric groups are polyphyletic, with the Indian Pedostibes embedded within a primarily South Asian clade of toads, containing the genera Adenomus, Xanthophryne, and Duttaphrynus. Southeast Asian Pedostibes on the other hand, are nested within a Southeast Asian clade, which is the sister lineage to the Southeast Asian river toad genus Phrynoidis. We demonstrate that Indian and Southeast Asian Pedostibes are not only allopatric and polyphyletic, but also exhibit significant differences in morphology and reproductive mode, indicating that the Southeast Asian species’ are not congeneric with the true Pedostibes of India. As a taxonomic solution, we describe a new genus, Rentapia gen. nov. to accommodate the Southeast Asian species.     

Ligands of second generation platinum analogs decrease both platinum-induced DNA cross-linking and its ability to interact with 1-beta-D-arabinofuranosyl cytosine to potentiate cytotoxic efficacy

We evaluated the cytotoxic and DNA cross-linking (CL) ability of four second generation platinum coordination complexes (TNO-6, JM-89, JM-8 and JM-9) delivered alone or in combination with 1-beta-D-arabinofuranosyl cytosine (ara-C) to human colon cancer cells (LoVo). Cell survival varied markedly as a function of the particular substitution moiety. JM-8 and JM-9 were virtually ineffective, even at concentrations as high as 50 micrograms/ml. At that concentration cis-diamminedichloroplatinum(II) (cis-DDP) killed greater than 99.99% of the cells. JM-82 was slightly more active while TNO-6 was the only derivative with appreciably higher cytotoxic activity due to an abrogation of the shoulder region of the type C survival curve. The highest CL effect was observed for cis-DDP followed closely by TNO-6. Very little CL effects were demonstrated for the other three analogs JM-82, JM-8 and JM-9 when measured 6 h after treatment. The combination of cis-DDP and ara-C augmented 10-fold the cytotoxic activity of cis-DDP alone, an effect accompanied by an almost 2-fold increase in CL; every other analog failed to interact in a potentiating manner (either cytotoxicity, or CL at 6 h) with the antimetabolite. Thus, it appears clear that the associated moieties of the Pt coordination complex play a fundamental role in reducing the interaction of the analogs with DNA (as reflected by the decreased CL and cytotoxic effects produced by each agent alone) and in totally preventing their interaction with ara-C to yield a potentiating lethal effect.