In vitro culture selection increases glyphosate tolerance in barley

In vitro culture of barley calluses has been used to produce plants with increased glyphosate tolerance. Calluses from immature embryos of barleyHordeum vulgare L. (Jeff) were cultured on Murashige and Skoog medium with 10^-6, 10^-5, 10^-4, 5×10^-4, 10^-3, or 10^-2M glyphosate for one, four or thirty months. Plants were regenerated from calluses maintained in glyphosate medium at 10^-6, 10^-5 or 10^-4M for four months, at 10^-5 or 5×10^-4M for one month and at 10^-5M for thirty months. The progeny of each regenerated plant was analyzed for response to glyphosate. Some progenies showed increased tolerance to glyphosate.     

Some events of mitosis and cytokinesis in the generative cell of Ornithogalum virens L.

The organization of the microtubule (Mt) cytoskeleton during mitosis and cytokinesis of the generative cell (GC) in Ornithogalum virens L. (bicellular pollen type, chromosome number, n = 3) from prophase to telophase/sperm formation was investigated by localization of -tubulin immunofluorescence using a conventional fluorescence microscope and a confocal laser scanning microscope. Chromosomes were visualized with DNA-binding fluorochrome dyes (ethidium bromide and 46-diamino-2-phenyl-indole). The GC of O. virens is characterized by G2/M transition within the pollen grain and not in the pollen tube as occurs in the majority of species with bicellular pollen. It was found that prophase in the GC starts before anthesis and prometaphase takes place after 10 min of pollen germination. The prophase Mts are organized into three prominent bundles, located near the generative nucleus. The number of these Mt bundles is the same as the number of GC chromosomes, a relation which has not previously been considered in other species. The most evident feature in the prophase/ prometaphase transition of O. virens GC is a direct rapid rearrangement of Mt bundles into a network which appears to interact with kinetochores and form a typical prometaphase Mt organization. The metaphase chromosomes are arranged into a conventional equatorial plate, and not in tandem as is thought to be characteristic of GC metaphase. The metaphase spindle consists of kinetochore fibres and a few interzonal fibres which form dispersed poles. Anaphase is characterized by a significant elongation of the mitotic spindle concomitant with the extension of the distance between the opposite poles. At anaphase the diffuse poles converge. Cytokinesis is realized by cell plate formation in the equatorial plane of the GC. The phragmoplast Mts between two future sperm nuclei appear after Mts of the mitotic spindle have disappeared.Abbreviations DAPI 46-diamino-2-phenyl-indole - GC generative cell - GN generative nucleus - Mt microtubule This research was made possible in part due to TEMPUS Programme and Global Network for Cell and Molecular Biology UNESCO grants to Magorzata Bana. The experimental part of the work was done in Siena University. M. Banas is very grateful to Prof. Mauro Cresti and his group for scientific interest, offering the excellent laboratory facilities, and kind reception.     

A rapid urease test for presumptive identification of Cryptococcus neoformans

A rapid method to evidence urease activity is described. Urea hydrolysis and consequent production ammonia are detected by a chemical reaction producing a blue phenol compound (indophenol blue). Three hundred and three yeast were tested. Out of 107 urease-positive organisms detected by Christensen's Urea Agar Test (CUAT) 102 were positive by our method. No false negatives were observed by this method when testing 87 Cryptococcus strains. Ths practical screening test for presumptive identification of Cryptococcus neoformans is simple, unaffected by pH changes and requires 15 minutes to be performed.     

Candida albicans stress mannoproteins expression in superficial and systemic candidiasis

The presence of heat shock mannoproteins (HSMPs) reactive with sIgA was demonstrated in several C. albicans strains. The subculture of the C. albicans isolated from mucosal surfaces on Sabouraud's dextrose agar at 25 °C switched off the HSMP expression. A re-expression of the HSMPs was obtained in the same medium by shifting the temperature of incubation to 37 °C. However, expression of HSMPs in two strains isolated from deep infections was maintained during several subcultures on Sabouraud's dextrose agar at 25 °C. A glycoprotein of 200 kDa seemed to be the main HSMP reacting with vaginal sIgA. The data presented in this study suggest that factors other than temperature can influence the expression of C. albicans HSMPs and therefore these antigens should be referred as stress mannoproteins.Abbreviations HSMPs heat shock mannoproteins - MAb monoclonal antibody - sIgA secretory IgA     

Overall Informativity,OI, in DNA Polymorphisms Revealed by inter-AluPCR: Detection of Genomic Rearrangements

We studied two systems of multilocus markers revealed by PCR using primers directing amplification betweenAlurepeats in a tail-to-tail orientation. Genomic polymorphisms were detected as the presence or absence of the electrophoretic bands representing DNA fragments of a given length. A total of 104 such fragments segregating as Mendelian markers in a panel of eight CEPH families were analyzed by two-point linkage analysis. Fifty-one of these fragments were localized with respect to CEPH markers; they represented 33 loci, 7 of which were multiallelic. Locus-specific oligonucleotides were developed and used as hybridization probes to identify the mapped loci within a complex pattern of inter-AluPCR products. A great proportion of inter-AluPCR polymorphisms represented length variants within amplified DNA segments, while others were presumably due to mutations within the priming sites. To describe the expected number of informative loci per typing experiment we introduced a parameter called overall informativity (OI), which provides a single measure of the multiplex ratio and the informativity of markers contributing to a multilocus system (OIof a single locus is equivalent to its heterozygosity and cannot exceed 0.5 for a biallelic codominant marker). HighOIvalues (5.8 and 11.5) of the two presented systems of inter-AluPCR markers of random chromosomal distribution render them suitable for mapping genomic rearrangements such as genomic deletions in tumoral tissues. This was illustrated by the detection of loss of heterozygosity in the 9q22–qter region in sporadic colon cancer.     

Polypores new to Japan 1. Species ofPolyporus,with a note onP. hartmanni

Polyporus admirabilis, P. dictyopus, P. guianensis, P. pseudobetulinus, P. tubaeformis andP. udus are reported for Japan for the first time.Polyporus tubaeformis had been confused withP. melanopus, but the Japanese collections were conspecific with Norwegian isolates ofP. tubaeformis. A key to allPolyporus species in Japan is provided.Polyporus hartmanni is reported for the first time outside the Australian continent. As the species has a bipolar heterothallism and produces brown rot, its taxonomic relationship withPolyporus s. str. is discussed.The Japanese Science and Technology Agency (STA) is thanked by the authors for financial support.     

Transfer of heavy metals from sediment to fish,and their biliary excretion

Uptake and biliary excretion of metals were studied in rainbow trout, Oncorhynchus mykiss, exposed through spiked sediment to a mixture of seven heavy metals. Metal concentrations and toxicity of bile and blood plasma were used as indicators of exposure. Among the seven metals (Cd, Cr, Cu, Hg, Ni, Pb, and Zn) only three (Cu, Hg, and Pb) were concentrated in the bile (bile-plasma ratio >1). Bile-plasma ratios in the rainbow trout were similar to those found in rats for Cu and Hg. Daphnia magna bioassays were used to determine toxicity of bile and blood plasma in the same trout. Toxicity of bile and blood plasma increased after treatment with acid. An analysis of variance (ANOVA) showed that toxicity of bile and blood plasma to D. magna in metal-exposed trout was significantly correlated with (1) bile and blood plasma test concentration, (2) acid treatment of bile and blood plasma (hydrolysis of metal-plasma and metal-bile complexes) and (3) sediment concentration of metals during exposure of trout. In order to significantly detect the magnitude of the exposure to a xenobiotic the biomarker must respond in a dose- or time-dependent manner. Therefore, the potential use of bile toxicity as a biomarker of heavy metal exposure in fish is probably limited by the low bioconcentration of many of these toxicants in bile.     

The role of glutamate in swim initiation in the medicinal leech

Antagonists were used to investigate the role of the excitatory amino acid,l-glutamate, in the swim motor program ofHirudo medicinalis. In previous experiments, focal application ofl-glutamate or its non-NMDA agonists onto either the segmental swim-gating interneuron (cell 204) or the serotonergic Retzius cell resulted in prolonged excitation of the two cells and often in fictive swimming. Since brief stimulation of the subesophageal trigger interneuron (cell Tr1) evoked a similar response, we investigated the role of glutamate at these synapses. Kynurenic acid and two non-NMDA antagonists, 6,7-dinitroquinoxaline-2,3-dione (DNQX) and Joro spider toxin, effectively suppressed (1) the sustained activation of cell 204 and the Retzius cell following cell Tr1 stimulation and (2) the monosynaptic connection from cell Tr1 to cell 204 and the Retzius cell, but did not block spontaneous or DP nerve-activated swimming. Other glutamate blockers, including -d-glutamylaminomethyl sulfonic acid,l(+)-2-amino-3-phosphonoproprionic acid and 2-amino-5-phosphonopentanoic acid, were ineffective. DNQX also blocked both indirect excitation of cell 204 and direct depolarization of cell Tr1 in response to mechanosensory P cell stimulation. Our findings show the involvement of non-NMDA receptors in activating the swim motor program at two levels: (1) P cell input to cell Tr1 and (2) cell Tr1 input to cell 204, and reveal an essential role for glutamate in swim initiation via the cell Tr1 pathway.     

The nervous system of Tricladida. I. Neuroanatomy ofProcerodes littoralis (Maricola,Procerodidae): An immunocytochemical study

The organization of the nervous system ofProcerodes littoralis (Tricladida, Maricola, Procerodidae) was studied by immunocytochemistry, using antibodies to authentic flatworm neuropeptide F (NPF) (Moniezia expansa). Compared to earlier investigations of the neuroanatomy of tricladid flatworms, the pattern of NPF immunoreactivity inProcerodes littoralis reveals differences in the following respects: 1. Shape and structure of the brain. 2. Number and composition of longitudinal nerve cords. 3. Shape of branches of, and transverse connections between, main ventral nerve cords. 4. Composition of the pharyngeal nervous system. The rich innervation by NPF immunoreactive (IR) fibres and cells of the subepithelial muscle layer, the pharynx musculature and the musculature of the male copulatory apparatus indicates a neurotransmitter or neuromodulatory influence on muscular activity.