Growth responses of rice in ammonium-based nutrient solution with variable calcium supply

It is commonly known that calcium promotes NO₃ ^- uptake in many crop species. However, calcium enhancement of NH₄ ⁺ uptake by plants has received little attention. This study aimed to evaluate the effect of Ca supplements on NH₄ ⁺ uptake and plant growth in solution cultured rice. Supplemental Ca applied at vegetative and reproductive phases of plant ontogeny tended to stimulate NH₄ ⁺ absorption, and accordingly resulted in a better straw and grain yield. However, excessively supplied Ca (400 ppm) was detrimental to plant growth. Increases in straw and grain yield observed at Ca levels up to 300 ppm were linked to the Ca-enhanced activities of glutamine synthetase (GS), glutamate synthase (GOGAT), and ribulose 1, 5-bisphosphate carboxylase/oxygenase (Rubisco).     

Atmospheric input of inorganic nitrogen to the Western Mediterranean

Bulk inorganic nitrogen deposition was monitored over a period of 3 years at the Bavella Pass (Corsica, France). Annual fluxes range between 126 and 150mol.m^–2.d-^–1, increasing slightly with annual rainfall. Natural background average concentrations of rain water and associated fluxes were estimated from a classification of rain events into natural (Oceanic and Saharan), polluted and composite. Long range transport of incoming polluted air masses increases the atmospheric wet nitrogen input by at least a factor of 1.6 in this Mediterranean area. Extrapolation of atmospheric dissolved inorganic nitrogen input to the Western Mediterranean leads to fluxes of 80 to l00mol.m^–2.d-^–1. This atmospheric input is in the same order of magnitude as the inorganic nitrogen riverine input. As a consequence, the nitrogen budget for the Mediterranean has had to be reassessed. Atmospheric wet inorganic nitrogen input is of noticeable importance to marine Mediterranean ecosystems, representing on average 10 to 25% of new production in the Western Basin, with values of up to 60% in oligotrophic zones.     

Presence of primary and secondary males in a population of the protogynous Synbranchus marmoratus

Synbranchus marmoratus , the 'swamp eel', is a protogynous diandric fish. The primary and secondary males can be distinguished from each other easily by differences in gonadal morphology. Primary males have lobular, unrestricted testes with central efferent ducts. The secondary male has a 'lamellar' testis, efferent ducts are present in the ventral region (new formation), lateral supports and it is covered by the former ovarian capsule. The length of primary male varies from 13 to 88 cm while secondary males range from 56 to 91 cm. Transitional individuals vary between 45 and 60 cm in length. The swamp eel population studied is composed of 80% primary males and 20% secondary males. Although gonadosomatic indices are always higher in primary males, they increase in secondary ones as the newly acquired stage progresses. The lamellar organization of the gonad of secondary males, the absence of this kind of testis in individuals smaller than 56 cm, and the presence of hermaphroditic fish, is evidence for protogyny in this species.     

Adherence Patterns and DNA Probe Types of Escherichia coli Isolated from Diarrheal Patients in China

One hundred and seventy-two strains of Escherichia coli isolated from diarrheal patients in Beijing, P. R. China, were analyzed for plasmid DNA profile, HEp-2 cell adherence ability and reactivity to 10 previously described DNA probes. They had not been recognized as pathogenic E. coli in China. Of the 110 strains tested, 76 (69%) contained one or multiple large plasmids. Of the 71 strains with the large plasmids 64 could adhere to HEp-2 cells. Of the 172 strains, 102 (59.3%) were hybridized with at least one of the 10 probes. Of those, seven strains hybridized with enteroaggregative E. coli (EAggEC) probe. Their serotypes were O128 (two strains), O6 (one strain), and O111 (one strain). Three strains were untypable. Six and three strains were hybridized with enteropathogenic E. coli (EPEC) attaching and effacing genes (eae) or EPEC adherence factor (EAF) probe, respectively. Two non-O157: H7 strains hybridized with enterohemorrhagic E. coli (EHEC) probe. Seventy-two strains (41.9%) hybridized with shiga-like toxin 2 or 1 (SLT2 or SLT1) probes. Among the SLT1 or SLT2 probe-positive strains, 54 hybridized with invasive (INV) plasmid probe developed for identification of enteroinvasive E. coli (EIEC) and Shigella species. The INV and SLT probe-positive strains might represent a new variety of verotoxin-producing E. coli (VTEC).     

Transformation of haploid, microspore-derived cell suspension protoplasts of rice (Oryza sativa L.)

We compared the transient activity of three cereal gene-derived promoter-gus fusions and the efficiency of selection mediated by three different selectable genes in a polyethylene glycol transformation system with haploid cell suspension protoplasts of rice. The maize ubiquitin promoter was found to be the most active in transformed protoplasts, and selection on ammonium glufosinate mediated by the bar gene was the most efficient for producing resistant calluses. Cotransformation of protoplasts with two separate plasmids carrying the gus and the bar genes, at either a 21 or 11 ratio, led to 0.8 × 10^–5 and 1.6 × 10^–5 resistant callus recovery frequencies and 59.7 and 37.9 cotransformation efficiencies respectively. No escapes were detected in dot blot analyses of 100 resistant calluses with a probe consisting of the bar coding region. Cotransformation efficiency, based on resistance to basta and -glucuronidase staining of the leaf tissue of 115 regenerated plants, was 47%. Resistance tests and Southern analysis of seed progenies of three diploid transgenic plants demonstrated homozygous integration of multiple copies of the transgene at one locus at least in the first plant, heterozygous integration at one locus in the second plant and heterozygous integration at two loci in the third plant.Abbreviations PEG polyethylene glycol - T₀ regenerated transgenic plant - GUS -glucuronidase - CaMV cauliflower mosaic virus - ARE anaerobic responsive element - OCS octopine synthase - T₁ first generation progeny of transgenic plants     

Combination of lamin immunocytochemistry and in situ hybridization for the analysis of chromosome copy numbers in tumor cell areas with high nuclear density

We describe the application of lamin immunocytochemistry (ICC) and single- or double-target fluorescence in situ hybridization (FISH) on 4 microm thick frozen tissue sections as a method to facilitate scoring of aberrant chromosome copy numbers in colonic tumors. Analysis of FISH signals in colon tissue sections is often hampered by overlap and truncation of epithelial nuclei, due to the density of the epithelial cells. Furthermore, on the basis of nuclear staining it is often difficult to determine whether or not nuclei are overlapping, or adjoining. Therefore, reliable evaluation of (F)ISH signals to screen for genomic changes was until now mainly restricted to isolated nuclei obtained from relatively thick tissue sections. In this study the applicability of lamin ICC, to stain the nuclear periphery and to distinguish individual nuclei, combined with the FISH procedure is explored to solve this problem for colon epithelium. For ICC we applied the alkaline phosphatase (APase)-Fast Red detection method, since the fluorescent precipitate of this reaction resists extensive proteolytic digestion as needed for efficient FISH on tissue sections. Chromosome copy numbers could easily be determined in 4 microm thick frozen tissue sections by combining lamin ICC and FISH. The ratio of the copy numbers of the chromosomes 7 and 17 could be determined in frozen tissue sections after combined lamin ICC and double-target FISH. It is concluded that the combination of lamin ICC and FISH improves chromosome copy number analysis and can be used to investigate genomic changes in different tumor compartments in thin frozen tissue sections.     

Purification and characterization of Kurloff cell sialoglycoproteins with acid phosphatase activity

The majora2–6 sialoglycoproteins in detergent-extracts of Kurloff cells were purified by anion-exchange andSambucus nigra agglutinin-affinity chromatographies. The similar ultrastructural localisations of (1)S. nigra agglutinin-gold conjugates and (2) acid phosphatase activities on the Kurloff body and particularly on its myelin figures indicated that the majora2-6 sialoglycoproteins of the Kurloff cell had acid phosphatase activity. Two-dimensional electrophoresis showed that these tartrate-sensitive phosphatases corresponded to 2 acidic (pI 3.4–3.7) polypeptides of 36 and 34 kDa. Hydrolysis with peptide-N-glycosidases F gave a 33 kDa apoprotein rich in alanine, glutamic acid, tyrosine and lysin. A lectin-affinity study demonstrated that they contained hybrid type bisected and fucosylatedN-linked oligosaccharides. Cytotoxic properties were previously attributed to Kurloff cells and other studies suggested that not only acid phosphatases but alsoa2-6-linked sialic acid residues themselves may participate in natural killer activity.