Cone monochromacy and a reversed Purkinje shift in the gerbil

Retinal spectral sensitivity of the gerbil (Meriones unguiculatus) shows that this animal has a unique photoreceptor complement: there is only a single class of cone and the spectrum for these receptors is peak shifted toward the short wavelengths relative to the spectra obtained from rods.     

The opsins of the vertebrate retina: insights from structural,biochemical, and evolutionary studies

The vertebrate retina contains several classes of visual pigments responsible for such diverse functions as image- and nonimage-forming vision, the entrainment of circadian cycles, and the pupilary light response. With vision being vital to the survival of many species, the elucidation of the structural and biochemical properties of visual pigments has been the focus of a large body of research that has led to rapid advances in the field of photoreception. In this review, the current understanding of the structure, function, biochemistry, and evolution of the opsins that make up the photopigments in the vertebrate retina will be reviewed. These include the rod and cone opsins, melanopsin, RGR, peropsin, and VA-opsin. The goal is to highlight important questions that have been answered and to define some of the remaining questions in the field that will provide future directions for research.     

Is ATP synthesized by a vacuolar-ATPase in the extremely halophilic bacteria?

The proton-dependent synthesis of ATP was demonstrated in representative members of the generaHalobacterium, Haloarcula, andHaloferax. In all cases, synthesis was not inhibited by nitrate or N-ethylmaleimide, inhibitors of the vacuolar-like ATPase found in Archaea, but was affected by azide, an inhibitor of F₀F₁-ATP syntheses. These observations extend the earlier observations withHalobacterium saccharovorum and suggest that ATP synthesis in these organisms is brought about by an F₀F₁-APT synthase.     

Pigment distribution in cyanobacteria: An in vivo microspectroscopic investigation

Summary In vivo microspectroscopy represents an effective and reliable technique to study pigment composition and distribution. In contrast to traditional extractive techniques, it preserves the integrity of biological specimens, without modifying the nature of the pigments. The spectroscopic apparatus we used is very simple and consists of a common microscope equipped with a monochromator, a photomultiplier, and two pinhole diaphragms. Absorption spectra obtained by means of this apparatus on different species of cyanobacteria are presented.     

Biotransformation of a dietary sesterterpenoid in the Mediterranean nudibranchHypselodoris orsini

The metabolic relationship between the marine molluscHypselodoris orsini and the spongeCacospongia mollior has been reinvestigated. The predator-prey association has been confirmed even though the metabolic patterns of the two invertebrates are substantially different. Most probably the nudibranch converts the main sponge metabolite, the sesterterpenoid scalaradial (1), into a less oxygenated related metabolite, deoxoscalarin (4), followed by a second chemical transformation leading to a new sesterterpenoid, 6-keto-deoxoscalarin (5) which is selectively compartmentalized into some dorsal glands, mantle dermal formations (MDFs), strategically distributed near the gills. 6-keto-deoxoscalarin (5) has been characterized by 1D and 2D NMR methods. Finally, the unusual association of some Chromodorididae molluscs with sponges containing sesterterpenoids suggests a further analysis of their taxonomical collocation is required.     

Partial sequence of the gene for a serine protease from a halophilic archaeumhaloferax mediterranei R4, and nucleotide sequences of 16S rRNA encoding genes from several halophilic archaea

A part of the gene coding for a halophilic serine protease from a halophilic archaeumHaloferax mediterranei R4 was amplified by PCR and its 672 nucleotide sequence was determined. Tentative translation to the amino acid sequence suggested that the enzyme was quite similar to halolysin produced by another halophilic archaeum strain 172P1. Nucleotide sequences of 16S rRNA encoding genes from 9 halophilic archaea were determined. Alignment of 19 sequences known so far showed that there are more than 20 positions carrying bases or deletions specific for each halobacterial genus:Halobacterium, Haloarcula, Haloferax, andHalococcus.     

Anthelmintic activity of a benzimidazoline compound in sheep by abomasal infusion

Summary In vitro and in vivo data on the benzimidazoline compound indicate anthelmintic potential when introduced directly into the abomasum.     

Effect of tingenone,a quinonoid triterpene,on growth and macromolecule biosynthesis inTrypanosoma cruzi

Summary Tingenone and horminone, two natural quinonoid substances, inhibited the in vitro growth ofTrypanosoma cruzi, 30 M drug concentration producing total inhibition of growth. Tingenone inhibited total uptake and incorporation of [³H]thymidine, [³H]uridine, L-[³H]leucine into parasite macromolecules. Other quinonoids assayed were either less effective (abruquinone A) or even quite inactive (visminone B and ferruginin B). Investigation of several mechanisms for the cytotoxic action of tingenone pointed to the interaction with DNA as the most likely factor involved. Tingenone also inhibited the growth ofCrithidia fasciculata, but the drug was significantly less active on this organism than onT. cruzi.This work was supported by grants of UNDP/World Bank/World Health Organization Special Programme for Research and Training in Tropical Diseases, Organization of American States (Multinational Programme of Biochemistry) and Programa Nacional de Enfermedades Endémicas (SECYT), República Argentina. A preliminary account was given at the Workshop on Oxidative Damage and Related Enzymes, Frascatti (Italy), 1983.     

Total synthesis of orellinine,a minor toxic component of the fungusCortinarius orellanus fries

Summary The 3,3,4,4-tetrahydroxy-2,2-bipyridyl-N-oxide has been synthesized by dealkylation of the corresponding tetramethyl derivative. The chemical properties of this compound are identical to those reported for the minor fungal toxin ofCortinarius orellanus, orellinine.This work is part of the Tesi di Laurea of Miss Cinzia Pierucci.     

Protein-O-mannosyltransferases in virulence and development

Protein-O-mannosyltransferases (Pmt proteins) catalyse the addition of mannose to serine or threonine residues of secretory proteins. This modification was described first for yeast and later for other fungi, mammals, insects and recently also for bacteria. O-mannosylation depends on specific isoforms of the three Pmt1, 2 and 4 subfamilies. In fungi, O-mannosylation determines the structure and integrity of cell walls, as well as cellular differentiation and virulence. O-mannosylation of specific secretory proteins of the human fungal pathogen Candida albicans and of the bacterial pathogen Mycobacterium tuberculosis contributes significantly to virulence. In mammals and insects, Pmt proteins are essential for cellular differentiation and development, while lack of Pmt activity causes Walker-Warburg syndrome (muscular dystrophy) in humans. The susceptibility of human cells to certain viruses may also depend on O-mannosyl chains. This review focuses on the various roles of Pmt proteins in cellular differentiation, development and virulence. Received 6 September 2007; received after revision 3 October 2007; accepted 5 October 2007     

Aberrant,canavanyl protein formation and the ability to tolerate or utilize L-canavanine

Summary L-Canavanine, 2-amino-4-(guanidinooxy)butyric acid, and L-arginine incorporation into de novo synthesized proteins was compared in six organisms. Utilizing L-[guanidinooxy¹⁴C]canavanine and L-[guanidino¹⁴C]arginine at substrate saturation, the canavanine to arginine incorporation ratio was determined in de, novo synthesized proteins.Caryedes brasiliensis andSternechus tuberculatus, canavanine utilizing insects;Canavalia ensiformis, a canavanine storing plant; and to a lesser extentHeliothis virescens, a canavanine resistant insect, failed to accumulate significant canavanyl proteins. By contrast,Manduca sexta, a canavanine-sensitive insect, andGlycine max, a canavanine free plant, readily incorporated canavanine into newly synthesized proteins. This study supports the contention that the incorporation of canavanine into proteins in place of arginine contributes significantly to canavanine's antimetabolic properties.     

Genetics of toxin production and resistance in phytopathogenic bacteria

Genes for phytotoxin production have been identified and cloned from several phytopathogenic pseudomonads. These genes comprise physically linked clusters that have been located both on the chromosome and on endogenous plasmids. Contained within these genetic regions are resistance genes specific to those toxins that have a bactericidal component to their activity. DNA sequences required for toxin production are often conserved among bacteria with divergent host specificities, suggesting the ability of toxin genes to be transferred between bacteria. Toxins are usually modulators of plant pathogenicity, their production causing a significant increase in disease severity. In one case, however, toxin production appears to be a major contributor to the basic pathogenicity of a plant pathogenic bacterium.     

In vitro metabolism of the trichothecene 4-monoacetoxyscirpenol by fungus- and non-fungus-feeding insects

Summary The metabolism of the trichothecene 4-monoacetoxyscirpenol by intact gut tissue was determined in the fungus-feeding Nitidulid,Carpophilus hemipterus (L.) and the non-fungus-feeding caterpillars, the fall armyworm,Spodoptera frugiperda (J. E. Smith) and the corn earworm,Heliothis zea (Boddie). The primary metabolite was the hydrolysis product scirpentriol. The amount of metabolism by theC. hemipterus larvae was ca 10 times that of the caterpillars on a per mg protein basis, suggesting metabolic adaptation for feeding on fungi that may contain mycotoxins.Acknowledgment. The authors wish to thank S. Taylor for technical assistance.The mention of firm names or trade products does not imply that they are endorsed or recommended by the U.S. Department of Agriculture over other firms or similar products not mentioned.     

Pheromone components of the female elephant hawk-moth,Deilephila elpenor,and the silver-striped hawk-moth,Hippotion celerio

By means of gas chromatographic and mass spectroscopic methods, and combined GC-electroantennogram and electrosensillogram techniques, (E)-11-hexadecenal and (10E, 12E)-10,12-hexadecadienal [(E,E)-bombykal is also the main constituent of the pheromone of the silver-striped hawk-mothHippotion celerio. The biological activity of the substances was demonstrated with electroantennogram and single cell recording, and the physiological efficacy of the different hexadecadienal isomers compared.Pheromones, 79; as Pheromones, 78 is taken: Wu, Cai-Hong, and Bestmann, H. J., Chinese Science Bulletin34 (1989) 1475; pheromones, 77: Attygalle, A. B., Steghaus0Kovac, S., Ahmed, V. U., Maschwitz, U., Vostrowsky, Ol, and Bestmann, H. J., Naturwissen-schaften78 (1991) 90.     

Identification of a new predaceous stink bug pheromone and its attractiveness to the eastern yellowjacket

Summary Males ofPodisus fretus (Hemiptera: Pentatomidae) release a long-range attractant pheromone containing linalool (49.0%), (E)-2-hexenal (34.5%), benzyl alcohol (12.0%), nerolidol (2.0%),-terpineol (1.1%), and traces of several other compounds. The eastern yellowjacket,Vespula maculifrons (Hymenoptera: Vespidae), is attracted to artificial pheromones forP. fretus and for the sympatric species,Podisus maculiventris.The authors thank Mr T.J. Henry of the USDA Systematic Entomology Laboratory and Dr J.E. McPherson, Southern Illinois University, for examining the pentatomid species and Dr A.S. Menke, USDA-SEL, for determining the yellowjacket species. We also thank S. Wilzer for technical assistance. Mention of a company name does not imply endorsement by the US Department of Agriculture.     

Antimalarial drugs: recent advances in molecular determinants of resistance and their clinical significance

Molecular determinants of antimalarial drug resistance are useful and informative tools that complement phenotypic assays for drug resistance. They also guide the design of strategies to circumvent such resistance once it has reached levels of clinical significance. Established resistance to arylaminoalcohols such as mefloquine and lumefantrine in SE Asia is mediated primarily by gene amplification of the P. falciparum drug transporter, pfmdr1. Single nucleotide polymorphisms in pfmdr1, whether assessed in field isolates or transfection experiments, are associated with changes in IC₅₀ values (to arylaminoalcohols and chloroquine), but not of such magnitude as to influence clinical treatment outcomes. Recently described emerging in vitro resistance to artemisinins in certain areas correlates with mutations in the SERCA-like sequence PfATP6 and supports PfATP6 as a key target for artemisinins. Received 13 February 2006; revised after revision 7 March 2006; accepted 29 March 2006     

Peroxidase and gamma-glutamyl transpeptidase activities duringEimeria nieschulzi (Apicomplexa) and/orNippostrongylus brasiliensis (Nematoda) infections in the rat

Summary Results suggest that malabsorption of amino acids which occurs duringEimeria nieschulzi andNippostrongylus brasiliensis infections in rats is not due to impairment by intestinal inflammation of gamma-glutamyl transpeptidase activity.Supported by NIH MBRS grant RR08012-13.