Mesoflavibacter zeaxanthinifaciens gen. nov., sp. nov., a novel zeaxanthin-producing marine bacterium of the family Flavobacteriaceae

A novel strictly aerobic, gliding, Gram-negative, rod-shaped, halo- and mesophilic bacterium (TD-ZX30(T)) was isolated from a seawater sample collected on the Pacific coastline of Japan near Kamakura City (Fujisawa, Kanagawa). The temperature range for growth of TD-ZX30(T) was between 16 and 44 degrees C. The DNA G+C content was 32.0mol%. The predominant fatty acids were iso-C(15:1) G, iso-C(15:0), iso-C(16:0) 3-OH, iso-C(15:0) 3-OH, Summed feature (iso-C(15:0) 2-OH and/or C(16:1)omega7c), iso-C(17:0) 3-OH, and C(15:0). MK-6 was the only respiratory quinone. Zeaxanthin was the major carotenoid pigment produced but flexirubin-type pigments were not produced. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that TD-ZX30(T) belonged to a distinct lineage in the family Flavobacteriaceae, sharing 93.9% sequence similarity with the nearest species Olleya marilimosa. TD-ZX30(T) could be distinguished from the other members of the family Flavobacteriaceae by a number of chemotaxonomic and phenotypic characteristics. The results of polyphasic taxonomic analyses suggested that TD-ZX30(T) represents a novel genus and a novel species, for which the name Mesoflavibacter zeaxanthinifaciens gen. nov., sp. nov. is proposed. The type strain is TD-ZX30(T) (=NBRC 102119=CCUG 53614=DSM 18436).     

Nickel and iron incorporation into soluble hydrogenase of Alcaligenes eutrophus

Archives of Microbiology - Qualitative and quantitative determination of proteins of the soluble hydrogenase (hydrogen: NAD+ oxidoreductase, EC 1.12.1.2) from Alcaligenes eutrophus H16 was done by...     

<Emphasis Type="Italic">Agrobacterium rhizogenes</Emphasis> is a useful transporter for introducing T-DNA of the binary plasmid into the chrysanthemum, <Emphasis Type="Italic">Dendranthema grandiflorum</Emphasis> Kitamura,genome

Agrobacterium rhizogenes was used for efficient transformation of chrysanthemum. Two types of Agrobacterium, A. rhizogenes (A-13) and A. tumefaciens (LBA4404), which harbor pIG121-Hm, were employed for infection. In the A. rhizogenes-infected explants, hairy roots were not observed on any tested medium or culture condition. When explants were cultured on shoot induction medium, calli were formed at the cutting edge within 4–6 weeks of culture, and shoot primordia were observed on the callus surface after 2 weeks of callus formation. Consequently, with gus introduction, a significantly higher transformation rate was observed for A. rhizogenes (6.0%) compared with A. tumefaciens (3.3%). However, only 0.6% of the frequency of rol insertion was exhibited in A. rhizogenes mediation. These results indicate that A. rhizogenes effectively introduces T-DNA of the binary plasmid into the chrysanthemum genome by introducing Ri T-DNA at a low frequency. It also indicates that the system is a useful alternative for the transformation of chrysanthemum.     

Multiple shifts between violet and ultraviolet vision in a family of passerine birds with associated changes in plumage coloration

Colour vision in diurnal birds falls into two discrete classes, signified by the spectral sensitivity of the violet- (VS) or ultraviolet-sensitive (UVS) short wavelength-sensitive type 1 (SWS1) single cone. Shifts between sensitivity classes are rare; three or four are believed to have happened in the course of avian evolution, one forming UVS higher passerines. Such shifts probably affect the expression of shortwave-dominated plumage signals. We have used genomic DNA sequencing to determine VS or UVS affinity in fairy-wrens and allies, Maluridae, a large passerine family basal to the known UVS taxa. We have also spectrophotometrically analysed male plumage coloration as perceived by the VS and UVS vision systems. Contrary to any other investigated avian genus, Malurus (fairy-wrens) contains species with amino acid residues typical of either VS or UVS cone opsins. Three bowerbird species (Ptilonorhynchidae) sequenced for outgroup comparison carry VS opsin genes. Phylogenetic reconstructions render one UVS gain followed by one or more losses as the most plausible evolutionary scenario. The evolution of avian ultraviolet sensitivity is hence more complex, as a single shift no longer explains its distribution in Passeriformes. Character correlation analysis proposes that UVS vision is associated with shortwave-reflecting plumage, which is widespread in Maluridae.     

Excision of the piggyBac transposable element in vitro is a precise event that is enhanced by the expression of its encoded transposase

The piggyBac Lepidopteran transposable element moves from the cellular genome into infecting baculovirus genomes during passage of the virus in cultured TN-368 cells. We have constructed genetically tagged piggyBac elements that permit analysis of excision when transiently introduced on plasmids into the piggyBac-deficient Spodoptera frugiperda IPLB-SF21AE cell line. Precise excision of the element from these plasmids occurs at a higher frequency in the presence of a helper plasmid that presumably supplies the piggyBac transposase. The results suggest that the piggyBac transposon encodes a protein that functions to facilitate not only insertion, but precise excision as well. This is the first demonstration of piggyBac mobility from plasmid sources in uninfected Lepidopteran cells.     

Accumulation of genes for susceptibility to rust fungi for which barley is nearly a nonhost results in two barley lines with extreme multiple susceptibility

Nonhost resistance is the most common type of resistance in plants. Understanding the factors that make plants susceptible or resistant may help to achieve durably effective resistance in crop plants. Screening of 109 barley (Hordeum vulgare L.) accessions in the seedling stage indicated that barley is a complete nonhost to most of the heterologous rust fungi studied, while it showed an intermediate status with respect to Puccinia triticina, P. hordei-murini, P. hordei-secalini, P. graminis f. sp. lolii and P. coronata ff. spp. avenae and holci. Accessions that were susceptible to a heterologous rust in the seedling stage were much more or completely resistant at adult plant stage. Differential interaction between barley accessions and heterologous rust fungi was found, suggesting the existence of rust-species-specific resistance. In particular, many landrace accessions from Ethiopia and Asia, and naked-seeded accessions, tended to be susceptible to several heterologous rusts, suggesting that some resistance genes in barley are effective against more than one heterologous rust fungal species. Some barley accessions had race-specific resistance against P. hordei-murini. We accumulated genes for susceptibility to P. triticina and P. hordei-murini in two genotypes called SusPtrit and SusPmur, respectively. In the seedling stage, these accessions were as susceptible as the host species to the target rusts. They also showed unusual susceptibility to other heterologous rusts. These two lines are a valuable asset to further experimental work on the genetics of resistance to heterologous rust fungi.Electronic Supplementary Material Supplementary material is available in the online version of this article at http://dx.doi.org/10.1007/s00425-004-1319-1Abbreviations ff. spp Formae speciales - RIL Recombinant inbred line - DC Double cross - DC-S Progeny produced by selfing of double-cross plants     

Virulence is context-dependent in a vertically transmitted aquatic host–microparasite system

Recent work has suggested that the outcomes of host–symbiont interactions can shift between positive, neutral and negative depending on both biotic and abiotic conditions. Even organisms traditionally defined as parasites can have positive effects on hosts under some conditions. For a given host–parasite system, the effects of infection on host fitness can depend on host vigour, route of transmission and environmental conditions. We monitored sublethal microsporidian infections in populations of Gammarus pseudolimnaeus (Amphipoda: Gammaridae) from four cool water streams in southwestern Michigan, USA. Our objectives were to: (i) infer the mechanism of transmission (horizontal, vertical or mixed) from observed effects of infection on host fitness, (ii) determine if the magnitude of the effects on host fitness is a function of parasite load (infection intensity) compared with simple presence or absence of infection, and (iii) determine if there is variation in parasite effects on host fitness in isolated populations. PCR and DNA sequence analyses revealed that there were two microsporidia present among the four host populations: Dictyocoela sp. and Microsporidium sp. PCR screening of a subset of infected hosts showed that Dictyocoela sp. accounted for 90% of infections and was present in all four G. pseudolimnaeus populations, while Microsporidium sp. was found in two populations but was only relatively common in one. We found very low prevalence in males (∼5%), but high prevalence in females (range: 37–85%). Female fitness was positively associated with infection in two streams, resulting from either higher fecundity or more reproductive bouts. Infection had a negative effect on the number of reproductive bouts in a third population, and no effect on fecundity in a fourth population. Infection intensity explained additional variation in fecundity in one population; females with intermediate infection intensity had higher fecundity than females with either light or heavy infection intensity. Given the high prevalence of infection in females compared with males and the generally weak negative fitness effects coupled with some positive fitness effects, it is likely that both Dictyocoela sp. and Microsporidium sp. are primarily vertically transmitted, feminizing microsporidia. Our results suggest that microsporidian effects on G. pseudolimnaeus fitness were context-dependent and varied with host sex and local environment.     

Insight into the basis of root growth in Arabidopsis thaliana provided by a simple mathematical model

Plant organ growth changes under genetic and environmental influences can be observed as altered cell proliferation and volume growth. The two aspects are mutually dependent and intricately related. For comprehensive growth analysis, it is necessary to specify the relationship quantitatively. Here, we develop a simple mathematical model for this purpose. Our model assumes that the biological activity of a given organ is proportional to the cell number of the organ and is allocated into three aspects: cell proliferation, volume growth, and organ maintenance. We analyzed the growth of primary roots of Arabidopsis thaliana (L.) Heynh. in one tetraploid and four diploid strains using this model. The analysis determined various growth parameters, such as specific cost coefficients of cell proliferation and volume growth for each strain. The results provide insight into the basis of interstrain variations and ploidy effects in root growth.     

Entry into the stationary phase is associated with a rapid loss of viability and an apoptotic-like phenotype in the opportunistic pathogen Aspergillus fumigatus

When the opportunistic pathogen Aspergillus fumigatus entered the stationary phase, there was a rapid loss in cell viability which was associated with the appearance of markers characteristic of apoptosis, namely annexin V-FITC binding to the cytoplasmic membrane, demonstrating exposure of phosphatidylserine to the outer leaflet of the membrane; and TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling) staining of the nuclei, indicating DNA fragmentation. This was followed later by a loss of membrane integrity as revealed by propidium iodide staining. The development of the apoptotic phenotype was blocked when the protein synthesis inhibitor cycloheximide was added to the culture 1h prior to the onset of the stationary phase, demonstrating active participation of the cell. In addition, intracellular activity against substrates specific for caspase-1 and -8 also increased on stationary phase entry and the development of the apoptotic phenotype was blocked when the cell permeant caspase inhibitor Z-FAD-fmk was present in the medium. Cell death in A. fumigatus during the stationary phase therefore appears to share similarities to apoptotic cell death in higher eukaryotes and to be dependent on a caspase-like activity.     

Actin is present in a green alga that lacks cytoplasmic streaming

Summary Negative-staining of crude cytoplasmic extracts from cells of the green algaErnodesmis verticillata reveals the presence of numerous microfilaments. Rabbit skeletal muscle heavy-meromyosin binds to the microfilaments (in the absence of ATP) in typical arrowhead arrays. These results demonstrate that actin is present in this alga and it is suggested that actin may be involved in cytoplasmic contractions effecting wound healing, since cytoplasmic streaming does not occur in this organism.     

Isolation of a Highly Purified Capsular Polysaccharide from Salmonella enterica Serovar Typhi (Salmonella typhi) and Its Use in Serological Diagnostics of Typhoid Fever

For use in differential diagnostics of typhoid fever, samples of the capsular polysaccharide from Salmonella enterica serovar Typhi (usually named Vi-antigen) were isolated and characterized by physicochemical and serological methods. It was shown that only the sample of Vi-antigen with the minimal (0.57%) admixture of the corresponding lipopolysaccharide (LPS) from S. typhi retained a high serological activity in the tests with monoreceptor anti-Vi sera. However, it exhibited a substantially weaker reaction with sera from normal donors and patients with acute nontyphoid salmonelloses, than Vi-antigen preparations with a higher (0.8–1.2%) LPS content. The chromatographically pure Vi-antigen was further purified by triple reprecipitation with hexadecyltrimethylammonium bromide. The content of the LPS admixture in the resulting Vi-antigen samples was determined quantitatively by GC. A high purification level of the Vi-antigen from the LPS admixture allows us to hope that this preparation could serve as a basic component of the test system for the diagnostics of typhoid fever.     

Malleable skin coloration in cephalopods: selective reflectance, transmission and absorbance of light by chromatophores and iridophores

Nature's best-known example of colorful, changeable, and diverse skin patterning is found in cephalopods. Color and pattern changes in squid skin are mediated by the action of thousands of pigmented chromatophore organs in combination with subjacent light-reflecting iridophore cells. Chromatophores (brown, red, yellow pigment) are innervated directly by the brain and can quickly expand and retract over underlying iridophore cells (red, orange, yellow, green, blue iridescence). Here, we present the first spectral account of the colors that are produced by the interaction between chromatophores and iridophores in squid (Loligo pealeii). Using a spectrometer, we have acquired highly focused reflectance measurements of chromatophores, iridophores, and the quality and quantity of light reflected when both interact. Results indicate that the light reflected from iridophores can be filtered by the chromatophores, enhancing their appearance. We have also measured polarization aspects of iridophores and chromatophores and show that, whereas structurally reflecting iridophores polarize light at certain angles, pigmentary chromatophores do not. We have further measured the reflectance change that iridophores undergo during physiological activity, from "off" to various degrees of "on", revealing specifically the way that colors shift from the longer end (infra-red and red) to the shorter (blue) end of the spectrum. By demonstrating that three color classes of pigments, combined with a single type of reflective cell, produce colors that envelop the whole of the visible spectrum, this study provides an insight into the optical mechanisms employed by the elaborate skin of cephalopods to give the extreme diversity that enables their dynamic camouflage and signaling.     

Tissue-specific schedule of selective replication in Drosophila nasutoides

Summary Dramatic changes in the DNA composition of post-mitotic versus mitotic and germ line nuclei occur during development in different organisms. Drosophila nasutoides possesses n=4 chromosomes which were quantified with a microphotometer in females. The diploid (2 C) DNA content was 0.79 pg or 7.7×10⁸ nucleotide pairs, calculated from brain metaphases and calibrated with hen erythrocyte nuclei. The individual elements comprised X=9%, 2=16%, 3=13%, and 4=62% of the total complement. In polytene nuclei of larval salivary glands which had undergone 11 endoreplication cycles, chromosome 4 contained only 1.55% of total Feulgen DNA. Thus, in contrast with other Drosophila genomes, where under-replicating material is dispersed to all elements, a huge quantity of non-endoreplicating DNA is restricted to a single chromosome. This permits accurate determination of the timing of under-replication in the single cell. The data presented here suggest that the schedule is tissue-specific. Larval hind gut and salivary duct nuclei begin under-replication during the first endocycle, whereas adult and larval salivary glands mainly begin during the second cycle. In Malpighian tubules the onset of selective DNA syntheses occurs during either the first or the second endocycle.     

Efficient synthesis of a novel m-phenylene derivative as a selective EP4 agonist inducing follicular growth and maturation in the ovary

An efficient and straightforward synthesis of a novel m-phenylene derivative has been developed. The optically pure dibromo compound was selected as a starting material. Through a protocol involving the Prins reaction and two steps of the Horner–Wadsworth–Emmons reaction, the basic skeleton was constructed with appropriate alpha and omega side chains. The compound proved to be a highly selective EP₄ agonist and a possible drug candidate for maturation of the uterine cervix.     

Retinoic acid-metabolizing enzyme Cyp26a1 is essential for determining territories of hindbrain and spinal cord in zebrafish

Retinoic acid (RA) plays a critical role in neural patterning and organogenesis in the vertebrate embryo. Here we characterize a mutant of the zebrafish named giraffe (gir) in which the gene for the RA-degrading enzyme Cyp26a1 is mutated. The gir mutant displayed patterning defects in multiple organs including the common cardinal vein, pectoral fin, tail, hindbrain, and spinal cord. Analyses of molecular markers suggested that the lateral plate mesoderm is posteriorized in the gir mutant, which is likely to cause the defects of the common cardinal vein and pectoral fin. The cyp26a1 expression in the rostral spinal cord was strongly upregulated in the gir mutant, suggesting a strong feedback control of its expression by RA signaling. We also found that the rostral spinal cord territory was expanded at the expense of the hindbrain territory in the gir mutant. Such a phenotype is the opposite of that of the mutant for Raldh2, an enzyme that synthesizes RA. We propose a model in which Cyp26a1 attenuates RA signaling in the prospective rostral spinal cord to limit the expression of hox genes and to determine the hindbrain-spinal cord boundary.     

Alleviation of salt-induced stress on seed emergence using soil additives in a greenhouse

Use of sodium chloride (NaCl) as a deicing salt results in high concentrations of ions in roadside soils, which decreases seedling emergence in these areas. Greenhouse experiments performed in soil culture tested the efficacy of three soil fertilizers, gypsum (CaSO₄), potash (potassium chloride, KCl) and potassium nitrate (KNO₃), in alleviating NaCl stress on seedling emergence of three grass species exhibiting a range of salt tolerance, Poa pratensis (Kentucky bluegrass), Bouteloua gracilis (blue grama), and Puccinellia distans (alkali grass). Two-factor factorial designs were utilized for each species-fertilizer combination. Treatments of 5000 mg/L (0.086 M) NaCl with or without fertilizer, in concentrations that were equal to 0.5, 1, and 2 times the molar equivalent of 5000 mg/L NaCl were applied biweekly. Salt stress on Poa pratensis emergence was alleviated by all fertilizers with CaSO₄ having the greatest effect in alleviating NaCl stress and potash and potassium nitrate alleviating stress at lower treatment levels. Emergence of Bouteloua gracilis and Puccinellia distans was in most cases negatively effected by soil amendments.