Taxonomic status of the species of the green algal genusNeochloris

Komárek has recently reviewed the various species assigned to the green algal genusNeochloris Starr (Chlorococcales, Chlorococcaceae) and removed those with uninucleate vegetative cells to a new genus,Ettlia. Watanabe & Floyd, unaware ofKomárek's work, also reviewed the species ofNeochloris and distributed them among three genera—Neochloris, Chlorococcopsis gen. nov., andParietochloris gen. nov.—on the basis of details of the covering of the zoospore and the arrangement of the basal bodies of the flagellar apparatus. This paper reconciles these two treatments and makes additional recommendations at the ranks of genus, family, order, and class.     

Characterization of SSEA-1 glycolipids from the brain of a patient with fucosidosis

Neutral glycolipids from the brain of a patient with Fucosidosis were analyzed and two complex glycolipids containing five and eight sugars were isolated from the cortical grey matter. These two glycolipids reacted with antibodies recognizing the SSEA-1 [Le^x(X)] carbohydrate determinant. SSEA-1 glycolipids are normally expressed in human embryonic brain but are found in only small amounts in postnatal human brain. The accumulation of the two SSEA-1 glycolipids in Fucosidosis brain thus represents a defect which affects the normal developmentally regulated decrease in postnatal, expression of these glycolipids, and may be a contributing factor in the abnormal brain development associated with the disease. Chemical characterization of the two isolated glycolipids by gas chromatographic and mass spectrometric analyses has identified the two glycolipids as lacto-N-fucopentaosylceramide (III) and difucosyl-neolactonorhexaosylceramide.Abbreviations DCl direct chemical ionization - FAB tastatiom bombardment - GC gas chromatography - GSLs glycosphingolipids - MS mass spectrometry - SSEA-1 stage specific embryonic antigen-1 - TLC thin layer chromatographys     

The evolution of the Hox cluster: insights from outgroups

Two burgeoning research trends are helping to reconstruct the evolution of the Hox cluster with greater detail and clarity. First, Hox genes are being studied in a broader phylogenetic sampling of taxa: the past year has witnessed important new data from teleost fishes, onychophorans, myriapods, polychaetes, glossiphoniid leeches, ribbon worms, and sea anemones. Second, commonly accepted notions of animal relationships are being challenged by alternative phylogenetic hypotheses that are causing us to rethink the evolutionary relationships of important metazoan lineages, especially arthropods, annelids, nematodes, and platyhelminthes.     

Phylogeny of cardinalfishes (Teleostei: Gobiiformes: Apogonidae) and the evolution of visceral bioluminescence

The cardinalfishes (Apogonidae) are a diverse clade of small, mostly reef-dwelling fishes, for which a variety of morphological data have not yielded a consistent phylogeny. We use DNA sequence to hypothesize phylogenetic relationships within Apogonidae and among apogonids and other acanthomorph families, to examine patterns of evolution including the distribution of a visceral bioluminescence system. In conformance with previous studies, Apogonidae is placed in a clade with Pempheridae, Kurtidae, Leiognathidae, and Gobioidei. The apogonid genus Pseudamia is recovered outside the remainder of the family, not as sister to the superficially similar genus Gymnapogon. Species sampled from the Caribbean and Western Atlantic (Phaeoptyx, Astrapogon, and some Apogon species) form a clade, as do the larger-bodied Glossamia and Cheilodipterus. Incidence of visceral bioluminescence is found scattered throughout the phylogeny, independently for each group in which it is present. Examination of the fine structure of the visceral bioluminescence system through histology shows that light organs exhibit a range of morphologies, with some composed of complex masses of tubules (Siphamia, Pempheris, Parapriacanthus) and others lacking tubules but containing chambers formed by folds of the visceral epithelium (Acropoma, Archamia, Jaydia, and Rhabdamia). Light organs in Siphamia, Acropoma, Pempheris and Parapriacanthus are distinct from but connected to the gut; those in Archamia, Jaydia, and Rhabdamia are simply portions of the intestinal tract, and are little differentiated from the surrounding tissues. The presence or absence of symbiotic luminescent bacteria does not correlate with light organ structure; the tubular light organs of Siphamia and chambered tubes of Acropoma house bacteria, those in Pempheridae and the other Apogonidae do not.     

Structural Peculiarities of Na+,K+-ATPase Isozymes from the Calf Brain

Functionally active preparations of Na⁺,K⁺-ATPase isozymes from calf brain that contain catalytic subunits of three types (1, 2, and 3) were obtained using two approaches: a selective removal of contaminating proteins by the Jorgensen method and a selective solubilization of the enzyme with subsequent reconstitution of their membrane structure by the Esmann method. The ouabain inhibition constants were determined for the isozymes. The real isozyme composition of the Na⁺ pump from the grey matter containing glial cells and the brain stem containing neurons was determined. The plasma membranes of glial cells were shown to contain mainly Na⁺,K⁺-ATPase of the 11 type and minor amounts of isozymes of the 22(1) and the 31(2) type. The axolemma contains 21 and 31 isozymes. A carbohydrate analysis indicated that 11 enzyme preparations from the brain grey matter substantially differ from the renal enzymes of the same composition in the glycosylation of the 1 isoform. An enhanced sensitivity of the 3 catalytic subunit of Na⁺,K⁺-ATPase from neurons to endogenous proteolysis was found. A point of specific proteolysis in the amino acid sequence PNDNR⁴⁹² Y⁴⁹³ was localized (residue numbering is that of the human 3 subunit). This sequence corresponds to one of the regions of the greatest variability in 1-, 2-, 3-, and 4-subunits, but at the same time, it is characteristic of the 3 isoforms of various species. The presence of the 3 isoform of tubulin (cytoskeletal protein) was found for the first time in the high-molecular-mass Na⁺,K⁺-ATPase 31 isozyme complex isolated from the axolemma of brain stem neurons, and its binding to the 3 catalytic subunit was shown.     

Hectorella: A member of the betalain-suborderChenopodiineae of the orderCentrospermae

Roots ofHectorella caespitosa Hook. f. were induced to produce a red pigment which was shown to be a betalain and not an anthocyanin. These data indicate thatHectorella belongs to theChenopodiineae, the betalain suborder of theCentrospermae, and excludes alignment with the anthocyanin family theCaryophyllaceae.     

Elucidation of Structure of Lipid A from the Marine Gram-Negative Bacterium Pseudoalteromonas haloplanktis ATCC 14393T

The chemical structure of lipid A, from the marine -proteobacterium Pseudoalteromonas haloplanktis 14393, a main product of lipopolysaccharide hydrolysis (1% AcOH), was determined using chemical methods and NMR spectroscopy. The lipid A was shown to be -1,6-glucosaminobiose 1,4-diphosphate acylated with two (R)-3-hydroxyalkanoic acid residues at C3 and C3 and amidated with one (R)-3-hydroxydodecanoyl and one (R)-3-dodecanoyloxydodecanoyl residue at N2 and N2, respectively.     

Evaluation of the Pro-Lab ID ring system for the identification of medically important yeasts

We evaluated 151 coded isolates of medically important yeast species belonging to the genera Candida, Cryptococcus, Geotrichum, Rhodoturula, Saccharomyces and Torulopsis using the newly developed rapid Pro-Lab Identification Ring, PL 960 system (PLID-Ring). All isolates were concurrently identified by the API 20C and conventional procedures comprising macro- and micromorphology, assimilation and fermentation of various carbon and nitrogen compounds. The PLID-Ring system identified isolates of Candida albicans, C. kefyr, C. krusei, C. lusitaniae, C. parapsilosis, Rhodotorula rubra, and Torulopsis glabrata with 100% accuracy in 24 h. This system identified C guilliermondii and S. cerevisiae isolates with an accuracy of 90% and 86%, respectively, while those belonging to Cr. neoformans, T. candida (= C. famata), C. rugosa and C. tropicalis were identified with 38.4%, 50%, 12.5% and 50% accuracy, respectively. Three isolates of Cr. laurentii were not identified by the PLID-Ring system. The overall accuracy of the PLID-Ring system was 81.45% (123 of 151 isolates). However, the system does not include species such as Cr. laurentii in its data base. When these three Cr. laurentii isolates were excluded from the evaluation, the accuracy of the PLID-Ring system increased from 81.45% to 83.1%.     

The purification of the three trimannosyl-N-acetylchitobiose pentasaccharides from the urine of swainsonine-intoxicated sheep

A simple method for the preparative resolution of three Man₃GlcNAc₂ isomers called Ia, Ib and II has been designed. It consists mainly of the use of concanavalin A-Sepharose which allowed the total purification of Man₃GlcNAc₂-Ia, and then of anion-exchange resin in borate buffer-gradient to separate the Ib and II isomers. The purity of each oligosaccharide was checked by two HPLC methods. The use of these oligosaccharides for different analytical and biosynthetic purposes is discussed, and the unexpected resistance of one of the Man₃GlcNAc₂ alditols to the action of endo--N-acetylglucosaminidase H is noted.     

Succession in the southern part of the Canadian boreal forest

Forest succession following fire in a forest mosaic of northwestern Quebec has been studied in order to: (1) describe the successional pathways using communities of different ages and (2) evaluate convergence of successional pathways and possible effect of fire suppression on the establishment of steady-state communities. As a first step, ordination and classification techniques were used in order to remove changes in forest composition which are related to abiotic conditions. Then, ordinations based on tree diameter distributions were used to study shifts in species composition in relation to time since the last fire.Even under similar abiotic conditions, successional pathways are numerous. However, regardless of forest composition after fire, most stands show convergence toward dominance of Thuja occidentalis and Picea mariana on xeric sites and dominance of Abies balsamea and Thuja occidentalis on more mesic sites. Stable communities of >300 yr occur on xeric sites while on mesic sites directional succession still occurs after 224 yr. Nearly all species involved in succession are present in the first 50 yr following fire. Only Abies balsamea and Thuja occidentalis increase significantly in frequency during succession. Following initial establishment, successional processes can generally be explained by species longevity and shade tolerance. Early successional species may be abundant in the canopy for more than 200 yr while the rapid decrease of Picea glauca, a late successional species could be related to spruce budworm outbreaks. Considering the short fire rotation observed (about 150 yr), a steady-state forest is unlikely to occur under natural conditions, though it may be possible if fire is controlled.     

Evaluation of antiprotozoal and antimycobacterial activities of the resin glycosides and the other metabolites of Scrophularia cryptophila

Resin glycosides are secondary metabolites exclusive to the convolvulaceous plants. In this study, crypthophilic acids A–C (1–3), the first resin glycosides occurring in another family (Scrophulariaceae), and the other constituents of Scrophularia cryptophila were examined for in vitro antiprotozoal and antimycobacterial potentials. Except for crypthophilic acid B (2), all tested compounds exhibited growth-inhibitory effect against Trypanosoma brucei rhodesiense, with l-tryptophan (6) and buddlejasaponin III (7) being the most potent ones (IC₅₀'s 4.1 and 9.7 μg/ml). In contrast, the activity towards Trypanosoma cruzi was poor, and only crypthophilic acid C (3), 6 and 7 were trypanocidal at concentrations above 40 μg/ml. With the exception of 2 and 6, all compounds were active against Leishmania donovani. Harpagide (4) and 3 emerged as the best leishmanicidal agents (IC₅₀'s 2.0 and 5.8 μg/ml). Only compounds 3, 6 and 7 showed antimalarial activity against Plasmodium falciparum with IC₅₀ values of 4.2, 16.6 and 22.4 μg/ml. Overall the best and broadest spectrum activity was presented by compounds 3 and 7, as they inhibited all four parasitic protozoa. None of the isolates had significant activity against Mycobacterium tuberculosis (MICs >100 μg/ml) or were toxic towards mammalian (L6) cells. This is the first report of antiprotozoal activity for natural resin glycosides, as well as for harpagide (4), acetylharpagide (5), tryptophan (6) and buddlejasaponin III (7).     

Progress on the genetics of the N2-fixing actinorhizal symbiont Frankia

The actinomycete Frankia is of fundamental and ecological interests for several reasons including its wide distribution, its ability to fix nitrogen, differentiate into sporangium and vesicle (specialized cell for nitrogen-fixation), and to nodulate plants from about 24 genera. Here, we present a review on the genetics performed so far on Frankia. At the end of July 2001, 293 kbp of Frankia DNA sequences were found in the databases. Thirty five percent of these sequences corresponded to full gene or gene cluster sequences. These genes could be divided according to their role into 6 key activities: gene translation (rrnA and tRNA ^pro gene), proteolysis (pcr genes), assimilation of ammonium (glnA and glnII), protection against superoxide ions (sodF), nitrogen fixation (nif cluster), and plasmid replication. We present a review of these genetic islands; their function, expression, localization and particular properties are discussed. A comparative analysis of Frankia nif genes from various strains and species is presented. An improved nomenclature for some of these genes is suggested to avoid conflicts. Frankia plasmids DNA sequences are also presented. The novel trends in Frankia genetics are described.     

An ACTH-Like Peptide Immunocortin: Effect on the Activity of Cells from the Rat Adrenal Cortex

The effect of immunocortin, an ACTH-like decapeptide VKKPGSSVKV corresponding to the 11–20 sequence of the variable part of the human IgG1 heavy chain on the content of 11-hydroxycorticosteroids (CS) in rat adrenal glands and blood serum in vivo was studied. An intramuscular injection of immunocortin at a dose of 10 g/kg was found in an hour to induce a twofold decrease in CS content in the adrenal glands and a 1.8-fold increase in the blood serum CS content. At the same time, an immunocortin dose of 100 g/kg exerted practically no effect on the CS content and its dose of 1000 g/kg increased the CS content both in adrenal glands and in blood serum by 1.6 and 2.2 times, respectively. Four hours after the injection of any of the three doses of immunocortin, the CS content in adrenal glands did not differ from the control value, and after 24 h the content decreased threefold. Immunocortin was shown to be bound by the ACTH receptors in the membranes of the rat adrenal cortex with a high affinity and specificity (inhibiting the specific binding of ¹²⁵I-labeled ACTH-(11–24) peptide with K _i of 1.2 nM).     

Tracking down the "head blob": comparative analysis of wingless expression in the developing insect procephalon reveals progressive reduction of embryonic visual system patterning in higher insects

The evolution of larval head morphology in holometabolous insects is characterized by reduction of antennal appendages and the visual system components. Little insight has been gained into molecular developmental changes underlying this morphological diversification. Here we compare the expression of the segment polarity gene wingless (wg) in the pregnathal head of fruit fly, flour beetle and grasshopper embryos. We provide evidence that wg activity contributes to segment border formation, and, subsequently, the separation of the visual system and protocerebrum anlagen in the anterior procephalon. In directly developing insects like grasshopper, seven expression domains are formed during this process. The activation of four of these, which correspond to polar expression pairs in the optic lobe anlagen and the protocerebral ectoderm, has shifted to postembryonic stages in flour beetle and Drosophila. The remaining three domains map to the protocerebral neuroectoderm, and form by disintegration of a large precursor domain in flour beetle and grasshopper. In Drosophila, the precursor domain remains intact, constituting the previously described “head blob”. These data document major changes in the expression of an early patterning gene correlated with the dramatic evolution of embryonic visual system development in the Holometabola.     

Effects of varying sex pheromone component ratios on the zigzagging flight movements of the oriental fruit moth,Grapholita molesta

As the ratio of (E)-8-dodecenyl acetate (E8–12Ac) to (Z)-8-dodecenyl acetate (Z8–12Ac) increased past optimal low levels in the pheromone blend, fewer males were able to fly 2.5 m upwind to the source. The tracks of males that flew in plumes of such high-(E)off-blends were slower and narrower than those of males flying to lower-(E)blends. The tracks were narrower, first of all, because as the proportion of E8–12Ac increased, the males steered more into the wind. More of their thrust was directed upwind and therefore their groundspeed to either side of the windline was reduced. In addition, males also reduced their airspeeds to high-(E)blends, which contributed to the decreased groundspeeds and narrower tracks. No significant changes in the frequency of counterturning were found in response to increasing proportions of E8–12Ac. The inability to continue upwind flight in a plume of an off ratio was indicated by in-flight arrestment in the plume. Arrestment resulted from changes in the course angles steered by the males and the airspeeds flown.     

Conformational Properties of the CalliFMRF-Amide Series Neuropeptides

Conformational properties of five neuropeptides belonging to the calliFMRF-amide series with the Xaa-Pro-Yaa-Gln-Asp-Phe-Met-Arg-Phe-NH₂ homologous sequences were studied by the method of theoretical conformational analysis. Three members of these group [(1) (Xaa = Thr, Yaa = Gln), (2) (Xaa = Thr, Yaa = Ser), and (3) (Xaa = Yaa = Ser)] can stimulate the saliva secretion from the separated salivary gland of the Calliphora vomitoria fly, whereas two other calliFMRF-amides [(4) (Xaa = Lys, Yaa = Asn) and (5) (Xaa = Ala, Yaa = Gly)] are inactive in this biological test. Low-energy spatial structures of the studied compounds were determined by a conformational analysis. A comparison of the stable structures of the biologically active and inactive neuropeptides revealed a similarity in their conformational properties and allowed determination of the role of separate residues in the peptide folding. The calculations demonstrated that the C-terminal hexapeptide fragment identical in all the five peptides tends to form -helical structure, whereas the variable N-terminal tripeptide regions of calliFMRF-amides (1)–(5) form more conformationally flexible structures.     

Semax and Selank Inhibit the Enkephalin-Degrading Enzymes of Human Serum

Dose-dependent effect of synthetic heptapeptides Semax (Met-Glu-His-Phe-Pro-Gly-Pro) and Selank (Thr-Lys-Pro-Arg-Pro-Gly-Pro) on the enkephalin-degrading enzymes of human serum was demonstrated. The inhibitory effects of Semax (IC₅₀10 M) and Selank (IC₅₀20 M) are more pronounced than that of puromycin (IC₅₀10 mM), bacitracin, and some other inhibitors of peptidases. Beside the heptapeptides, their pentapeptide fragments also possessed an inhibitory effect; tri-, tetra- and hexapeptide fragments did not display such an effect. As the above enzymes take part in degradation of not only enkephalins but also other regulatory peptides, it can be assumed that one of the mechanisms of biological activity of Semax and Selank is related to this inhibitory activity of theirs.