Detailed description of four YAC contigs representing 17 Mb of chromosome 4 of Arabidopsis thaliana ecotype Columbia

The detailed arrangement of 563 YAC clones comprising four contigs covering ～17 Mbp of chromosome 4 is presented. YAC clones were positioned relative to each other and to markers by taking into account marker and end fragment hybridization data and the sizes of all YAC clones. This analysis made it possible to estimate physical distances between the majority of chromosome 4 markers. It also identified a relatively large number of YAC clones containing chimaeric inserts. The YAC contig map of the Columbia ecotype presents an important resource for map-based cloning experiments, rapid mapping of DNA sequences and large-scale genomic sequencing programs.     

Growth kinetics and fucoxanthin production of <Emphasis Type="Italic">Phaeodactylum tricornutum</Emphasis> and <Emphasis Type="Italic">Isochrysis galbana</Emphasis> cultures at different light and agitation conditions

Fucoxanthin is a carotenoid that exerts multiple beneficial effects on human health. However, reports comparing microalgae culture conditions and their effect on growth and fucoxanthin production are still limited. Isochrysis galbana and Phaeodactylum tricornutum cultures in different light (62.0, 25.9, 13.5, or 9.1 μmol photons m^-2 s^-1), mixing conditions (1 vvm aeration or 130 rpm agitation), and media compositions (F/2 and Conway medium) were studied for comparison of cellular growth and fucoxanthin production on F/2 medium. I. galbana showed a better adaptation to tested culture conditions in comparison with P. tricornutum, reaching 2.15?×?10⁷?±?4.07?×?10⁶ cells mL^-1 and a specific growth rate (μ) of 1.12?±?0.05 day^-1 under aerated conditions and 62.0 μmol photons m^-2 s^-1 light intensity. Fucoxanthin concentration was about 25 % higher in P. tricornutum cultures under 13.5 μmol photons m^-2 s^-1 light intensity and aerated conditions, but the highest fucoxanthin total production was higher in I. galbana, where 3.32 mg can be obtained from 1 L batch cultures at the 16th day under these conditions. Moreover, higher cell densities (~32.41 %), fucoxanthin concentration (~42.46 %), and total production (~50.68 %) were observed in I. galbana cultures grown in Conway medium, if compared with cultures grown in F/2 medium. The results show that the best growth conditions did not result in the best fucoxanthin production for either microalgae, implying that there is not a direct relationship between cellular growth and fucoxanthin production. Moreover, the results suggest that I. galbana cultures on Conway medium are strong candidates for fucoxanthin production, where 1.2 to 15 times higher fucoxanthin concentration are observed in comparison to macroalgal sources.     

Rapid on-site identification of the biocontrol agent of the Asian chestnut gall wasp

In classical biocontrol programmes, a rapid and correct identification of the introduced antagonist is a key issue during both the release and establishment monitoring phases. It is often difficult to distinguish morphologically cryptic species or immature stages. An accurate diagnosis can now be provided by molecular diagnostic methods. Among the conventional and real-time PCR-based methods, loop-mediated isothermal amplification (LAMP) is a particularly suitable technique as it allows a rapid amplification of target DNA directly in the field. During the programme implemented in Italy against the Asian chestnut gall wasp (ACGW) Dryocosmus kuriphilus, we developed a real-time LAMP assay, combined with a simple DNA extraction method, for rapid in-field identification of larvae, pupae, and adults of the biocontrol agent, the parasitoid Torymus sinensis. Validation of the assay comprised adults as well as preimaginal stages of parasitoids obtained from ACGW galls collected from different localities. Results confirmed the effectiveness of the LAMP assay to rapidly and specifically identify the target parasitoid in the field. This assay will be a valuable tool for quick on-site checking of the parasitism rate.     

Effects of hydropriming treatments on the invigoration of aged Dodonaea viscosa seeds and water‐holding polymer on the improvement of seedling growth in a lava field

Restoration requires techniques similar to those used in agriculture to improve germination and seedling vigor. We treated 6‐year‐old (collected in 2003, S‐2003) and 1‐month‐old (S‐2009) seeds of Dodonaea viscosa with hydropriming (HP). Seeds were made permeable with hot water prior to hydration for 24 or 48 hours (HP‐24 and HP‐48, respectively) followed by dehydration. The resulting seedlings exposed to both HP treatments were sown in a lava field in soil mixed with hydrogel (HG) under the shade projected by five vegetation patches. The effects of these treatments on germination, seedling field survival, and growth were assessed. HP‐24 in S‐2009 and HP‐48 in S‐2003 increased the germination percentage from 22.5 and 31.7% in control seeds (permeable seeds) to 63.3 and 98.3%, respectively. The seedlings‐2009 (from S‐2009) with HG maintained high survival in all vegetation patches. Seedlings‐2003, however, had low survival. The lack of HG was negatively related to the photon flux in each patch. Survival of seedlings‐2009 increased with HG of up to 398.41 µmol m^?2 s^?1; after which survival decreased. During the rainy season, HP enhanced seedling growth, except the basal diameters and number of leaves in the seedlings‐2003 with HP‐24. During the dry season, the effects of HG and HP were similar for all the seedlings. In the following rainy season, the priming effect was lost while HG continued to promote seedling growth. The combined use of HP and HG and the shade projected by the patches resulted in a successful vegetation recovery strategy.     

Three-dimensional Alginate-bead Culture of Human Pituitary Adenoma Cells

A three-dimensional culture method is described in which primary pituitary adenoma cells are grown in alginate beads. Alginate is a polymer derived from brown sea algae. Briefly, the tumor tissue is cut into small pieces and submitted to an enzymatic digestion with collagenase and trypsin. Next, a cell suspension is obtained. The tumor cell suspension is mixed with 1.2% sodium alginate and dropped into a CaCl₂ solution, and the alginate/cell suspension is gelled on contact with the CaCl₂ to form spherical beads. The cells embedded in the alginate beads are supplied with nutrients provided by the culture media enriched with 20% FBS. Three-dimensional culture in alginate beads maintains the viability of adenoma cells for long periods of time, up to four months. Moreover, the cells can be liberated from the alginate by washing the beads with sodium citrate and seeded on glass coverslips for further immunocytochemical analyses. The use of a cell culture model allows for the fixation and visualization of the actin cytoskeleton with minimal disorganization. In summary, alginate beads provide a reliable culture system for the maintenance of pituitary adenoma cells.     

Manganese accumulation in yeast cells

Summary Manganese accumulation was studied by room-temperature electron spin resonance (ESR) spectroscopy inSaccharomyces cerevisiae grown in the presence of increasing amounts of MnSO₄. Mn²⁺ retention was nearly linear in intact cells for fractions related to both low-molecular-mass and macromolecular complexes (free and bound Mn²⁺, respectively). A deviation from linearity was observed in cell extracts between the control value and 0.1 mM Mn²⁺, indicating more efficient accumulation at low Mn²⁺ concentrations. The difference in slopes between the two straight lines describing Mn²⁺ retention at concentrations lower and higher than 0.1 mM, respectively, was quite large for the free Mn²⁺ fraction. Furthermore it was unaffected by subsequent dialyses of the extracts, showing stable retention in the form of low-molecular-mass complexes. In contrast, the slope of the line describing retention of bound Mn²⁺ at concentrations higher than 0.1 mM became less steep after subsequent dialyses of the cell extracts. This result indicates that the macromolecule-bound Mn²⁺ was essentially associated with particulate structures. In contrast to Cu²⁺, Mn²⁺ had no effect on the major enzyme activities involved in oxygen metabolism except for a slight increase of cyanide-resistant Mn-superoxide dismutase activity, due to dialyzable Mn²⁺ complexes.     

Salmonellae as an Index of Pollution of Surface Waters

Screening enrichments of surface water specimens by means of a polyvalent fluorescent antibody reagent for the salmonellae yielded approximately 60% more positive specimens than was obtained by cultural procedures. It is not known what fraction of the excess of fluorescent antibody-positive over culturally positive specimens represents staining of non-salmonellae or non-arizonae as opposed to the staining of non-cultivatable organisms of these two genera. Cotton gauze and rayon-polypropylene fiber swabs were equally sensitive for collecting salmonellae from the streams examined. Tetrathionate enrichment incubated at 41.5 C appeared to be superior to selenite-cystine for isolation of salmonellae from surface waters. Twenty-eight serotypes of Salmonella and two serotypes of Arizona were identified in the 121 positive specimens. In water rated moderately polluted, 65% of all specimens tested were positive; in minimally polluted waters, 38% were positive; and in unpolluted streams, 44% were positive.     

Cohesive properties of axenically grown cells of the slime mould Dictyostelium discoideum

It has been found that Dictyostelium discoideum cells from the exponential growth phase of axenically grown cultures are cohesive, whereas those from stationary phase are not. These differences in cohesiveness are seen in phosphate buffer and in axenic medium. Stationary phase medium inhibits the aggregation of log phase cells; stationary phase cells inoculated into freshly prepared medium regain their cohesiveness. Stationary phase medium may contain an inhibitor of cell cohesion. pH differences between the two types of medium are not entirely responsible for loss of cohesiveness.     

Kalafungin, a New Antibiotic Produced by Streptomyces tanashiensis Strain Kala

Kalafungin is a new antimicrobial agent obtained from the culture broth of a soil isolate of Streptomyces tanashiensis, designated Streptomyces tanashiensis strain Kala UC-5063. Kalafungin is a chemically stable, nonpolyene agent which is ex-extremely inhibitory in vitro against a variety of pathogenic fungi, yeasts, protozoa, gram-positive bacteria, and, to a lesser extent, gram-negative bacteria.     

Application of Paper Chromatograms to the Study of Inducers of λ Bacteriophage in Escherichia coli

A procedure has been developed whereby paper chromatograms of agents which induce lambda bacteriophage in Escherichia coli can be developed using bioautographs with a lysogenic test system. Well-defined plaque-forming zones are produced indicating the area on the paper chromatogram where the active inducing material can be located. A mixture of the bacteriophage-inducing antibiotic, mitomycin C, and the noninducing antibiotic, paromomycin, was resolved into its components on paper strips with an ethyl acetate-methanol solvent system. The location of both antibiotics could thus be readily observed. Antibacterial and inducing activities were found to be identical with a crude fermentation solid, NSC-B-158,791. The use of this procedure for resolution of multicomponent inducing activities in antibiotic beers and for characterization of active components which may be potential antitumor antibiotics is indicated.