Investigation of toxic Alternaria metabolites potentially present in UK-produced foods

Literature on the occurrence and toxicology of Alternaria mycotoxins shows that a wide range of Alternaria metabolites have been described although relatively few have been fully characterised. It has been reported that about half of the wild-type Alternaria cultures tested are highly toxic to mammals or birds but the compounds responsible have rarely been identified. Very little information is available on the nature or incidence of Alternaria mycotoxins in commodities grown in the UK. Preliminary results of an investigation of UK foods demonstrate the presence of several cytotoxic compounds in an ethyl acetate extract from an A. alternata culture. A toxic fraction has been isolated which appears to contain a compound not previously identified as an Alternaria mycotoxin.     

Phenolic compounds of the subfamily pomoideae: A chemotaxonomic survey

The subfamily Pomoideae has been surveyed for leaf phenolics and it has been shown that flavone glycosides are present in the genera Sorbus, Aronia, Chaenomeles and Hesperomeles in addition to the previously reported occurrences in Crataegus, Malus and Pyrus. The dihydrochalcone phloridzin, a typical constituent of Malus, has also been found in Docynia. Arbutin and phenolic acid-calleryanin esters are apparently restricted to Pyrus. Naringenin and eriodictyol glucosides have been detected in Pyracantha, Sorbus, Photinia, Chaenomeles and Hesperomeles. A number of Pomoideae phenolics have been found in two Spiraeoideae genera; luteolin 7-glucoside,] luteolin 7-diglucoside, luteolin 7-rhamnosylglucoside and apigenin 7-glucoside in Exochorda and the dihydrochalcone trilobatin in Sorbaria. The chemotaxonomic evidence is consistent with the hypothesis that the Pomoideae evolved through a process of allopolyploidy from primitive members of the Spiracoideae and Prunoideae.     

Mycosporine glutamine and related mycosporines in the fungus Pyronema omphalodes

The structure of mycosporine glutamine, a new compound, has been established and its presence demonstrated in two fungi Pyronema omphalodes and Glomerella cingulata. Mycosporine glutamic acid has been isolated from Helvella leucomelaneae. Co-occurrence of normycosporine glutamine, mycosporine glutamine and glucosylmycosporine glutaminol has been demonstrated in the fungus P. omphalodes. A biosynthetic pathway is proposed. Mycosporines have been compared by HPLC.     

Increased Drought Tolerance through the Suppression of ESKMO1 Gene and Overexpression of CBF-Related Genes in Arabidopsis

Improved drought tolerance is always a highly desired trait for agricultural plants. Significantly increased drought tolerance in Arabidopsis thaliana (Columbia-0) has been achieved in our work through the suppression of ESKMO1 (ESK1) gene expression with small-interfering RNA (siRNA) and overexpression of CBF genes with constitutive gene expression. ESK1 has been identified as a gene linked to normal development of the plant vascular system, which is assumed directly related to plant drought response. By using siRNA that specifically targets ESK1, the gene expression has been reduced and drought tolerance of the plant has been enhanced dramatically in the work. However, the plant response to external abscisic acid application has not been changed. ICE1, CBF1, and CBF3 are genes involved in a well-characterized plant stress response pathway, overexpression of them in the plant has demonstrated capable to increase drought tolerance. By overexpression of these genes combining together with suppression of ESK1 gene, the significant increase of plant drought tolerance has been achieved in comparison to single gene manipulation, although the effect is not in an additive way. Accompanying the increase of drought tolerance via suppression of ESK1 gene expression, the negative effect has been observed in seeds yield of transgenic plants in normal watering conditions comparing with wide type plant.     

Centric diatom algae of volcanic Verkhneavachinsk lakes (Kamchatka)

Eleven representatives of diatom algae of the class Centrophyceae from the genera Aulacoseira (1), Conticribra (1), Cyclotella (5), Discostella (1), Stephanodiscus (2), and Thallasiosira (1) have been found in the phytoplankton of 5 volcanic lakes (Bakening volcano, Kamchatka). Stephanodiscus popovskayae, a species new for science, has been discovered in all the lakes, and a species new for the flora of Russia, Cyclotella gordonensis, has been found only in three lakes. The closest similarity in the composition of centric diatoms has been revealed between the lakes of a single water system: Lake Medvezh’e and Lake Verkhneavachinskoe.     

Molecular biotechnology of marine algae in China

Molecular biotechnology of marine algae is referred to as the biotechnology on the identification, modification, production and utilization of marine algal molecules. It involves not only the manipulation of macromolecules such as DNA, RNA and proteins, but also deals with low molecular weight compounds such as secondary metabolites. In the last decade, molecular systematic researches to investigate the relationship and to examine the evolutionary divergence among Chinese marine algae have been carried out by Chinese scientists. For example, RAPD has been widely used in several laboratories to elucidate genetic variations of the reds, such as Porphyra, Gracilaria, Grateloupia and the greens such as Ulva and Enteromorpha. Some important data have been obtained. The study on molecular genetic markers for strain improvement is now in progress. In 1990s, genetic engineering of economic seaweeds such as Laminaria, Undaria, Porphyra, Gracilaria and Grateloupia has been studied in China. For Laminaria japonica, the successfully cultivated kelp in China, a model transformation system has been set up based on the application of plant genetic techniques and knowledge of the algal life history. Progress has been made recently in incorporating a vaccine gene into kelp genome. Evidence has been provided showing the expression of gene products as detectable vaccines. In the present paper, the progress of molecular biotechnological studies of marine algae in China, especially researches on elucidating and manipulating nucleic acids of marine algae, are reviewed.     

GC/MS Examination of four Lycopodium species for alkaloid content

A GC/MS examination of extracts of Lycopodium clavatum var. borbonicum and L. deuterodensum revealed alkaloids which had not been previously observed in these species. New alkaloids have been found in L. australianum and in L. fastigiatum, two species which had not been investigated before.     

A developmental analysis of the histone patterns of two species of Xenopus and their hybrids

The histone patterns in Xenopus laevis and X. borealis have been examined at various developmental stages using acid-urea polyacrylamide electrophoresis. Qualitative differences between the two species have been demonstrated in the H1 fraction. These differences are not affected by alkaline phosphatase digestion. Quantitative changes during development in both H1 and H4 fractions have also been observed. In addition, histones from hybrids of the two species have been examined. H1 histones characteristic of both species are present by the neurula stage in laevis ♀ × borealis ♂ hybrids. Quantitative changes observed in borealis development are mimicked in laevis ♀ × borealis ♂ hybrid development.     

Comparative scanning electron microscope (SEM) study of miracidia of four human schistosome species

The miracidia of four human blood flukes, Schistosoma haematobium, S. intercalatum, S. mansoni and S. japonicum, have been studied by means of the scanning electron microscope (SEM). Differences have been observed in their respective dimensions, in the configuration of their terebratoria (apical papillae), in the shape of the epidermal plates, and in the distribution of the sensory receptors. The most evident differences have been noticed on the terebratoria where two main patterns of organization of the anastomosing membrane foldings have been described: (1) a ‘rosette’ pattern observed in S. haematobium and S. intercalatum and (2) a ‘honeycomb’ pattern in S. mansoni and S. japonicum. The structure and the taxonomic importance of these morphological features are analysed.     

A CIS-Dominant Mutation in ASPERGILLUS NIDULANS Affecting the Expression of the amdS Gene in the Presence of Mutations in the Unlinked Gene, amdA

A mutant producing very high levels of the acetamidase enzyme encoded by the amdS gene has been isolated in a strain containing the amdA7 mutation, which itself causes high levels of this enzyme. Genetic analysis has shown that this mutation, designated amdI66, is adjacent to the amdS gene and is cis-dominant in its effect. The amdI66 mutation has little effect on amdS expression when present in strains not containing the amdA7 mutation. Two other amdA mutations investigated also interact with the amdI66 mutation to result in high acetamidase levels. No interaction between amdI66 and any of the other putative regulatory genes affecting amdS expression has been observed. The amdI66 mutation has been located by fine structure mapping at the extreme end of the controlling region, which has previously been defined by genetic mapping (Hynes 1979). Analysis of this region has been extended by mapping new mutations resulting in loss of amdS expression. One of these defines the most extreme site capable of mutation to loss of gene function found so far.     

Pseudomonas aeruginosa and Achromobacter sp.: nitrifying aerobic denitrifiers have a plasmid encoding for denitrifying functional genes

In the present work, novel heterotrophic nitrifying and aerobic denitrifying bacteria have been isolated from greenwater system of coastal aquaculture. Based on the 16S rRNA gene, FAME analysis and biochemical test, the isolates have been identified as Pseudomonas aeruginosa and Achromobacter sp. These have been named as P. aeruginosa strain DBT1BNH3 and Achromobacter sp. strain DBTN3. Denitrifying functional genes such as nitrite reductase (nirS), nitric oxide reductase (qnorB) and nitrous oxide reductase (nosZ) genes have been identified. These strains found to have a 27 kb plasmid coding for nirS and nosZ. The possibility of horizontal transfer of plasmid among Pseudomonadaceae and Alcaligenaceae families in coastal aquaculture has been explored. Further, we have studied combined nitrification and oxygen tolerant denitrification potential in the same isolates.     

Tissue culture cultivation ofLaunaea nudicaulis Hook f. infected with a mosaic virus disease

Healthy and mosaic infected leaves ofL. nudicaulis have been cultivated onMS and modifiedMS media (MC). Profuse growth and differentiation of tissue have been obtained onMS medium in diseased tissues as compared to the modified medium. It has been found on bioassay that although there is no difference between the concentration of the virus in tissue culture and glasshouse material yet the incubation period of the virus is decreased in tissue cultures.     

Antiviral potential of Bulgarian medicinal plants

Medicinal plants have been widely used to treat a variety of infectious and non-infectious diseases. Bulgarian flora includes 4,300 plant species, over 500 of which are rare or endemic to the country or the Balkan region. The aim of the present work is to summarize comprehensively the investigations on the antiviral activity of Bulgarian medicinal plants from the past three decades. The effect of different extracts derived from in vitro propagated plants has been examined as well. The phytochemical composition and its influence on specific steps of the viral life cycle have been discussed in this paper. The review includes the following families: Amaryllidaceae, Fabaceae, Geraniaceae, Lamiaceae, Onagraceae, Ranunculaceae, Rosaceae, Scrophulariaceae and Rhodophyta. Special attention has been paid to viruses as important human pathogens.     

Molecular epidemiology of cryptosporidiosis: An update

Molecular tools have been developed to detect and differentiate Cryptosporidium at the species/genotype and subtype levels. These tools have been increasingly used in characterizing the transmission of Cryptosporidium spp. in humans and animals. Results of these molecular epidemiologic studies have led to better appreciation of the public health importance of Cryptosporidium species/genotypes in various animals and improved understanding of infection sources in humans. Geographic, seasonal and socioeconomic differences in the distribution of Cryptosporidium spp. in humans have been identified, and have been attributed to differences in infection sources and transmission routes. The transmission of C. parvum in humans is mostly anthroponotic in developing countries, with zoonotic infections play an important role in developed countries. Species of Cryptosporidium and subtype families of C. hominis have been shown to induce different clinical manifestations and have different potential to cause outbreaks. The wide use of a new generation of genotyping and subtyping tools in well designed epidemiologic studies should lead to a more in-depth understanding of the epidemiology of cryptosporidiosis in humans and animals.     

Exotic flagellates of coastal North Sea waters

Flagellate species have been shown to survive transocean passage by ballast water and the large dinoflagellateGymnodinium catenatum was introduced from Japanese to Tasmanian waters in this way.Gymnodinium mikimotoi—better known asGyrodinium aureolum—andFibrocapsa japonica as well asAlexandrium leeii are good candidates to have been introduced recently. Species which seem to have been introduced recently into the North Sea but apparently are transported from adjacent seas by currents into the region areGymnodinium chlorophorum andAlexandrium minutum. Species reported as introduced due to misidentifications areGymnodinium catenatum andLepidodinium viride. Under other names the speciesProrocentrum minimum, Prorocentrum redfieldii, andHeterosigma akashiwo have been known for a long time in the North Sea. The recent reports of threeChattonella species may be either due to introduction or they have been overlooked. The reasons why the introduction of flagellates into coastal North Sea waters is difficult to prove will be discussed.     

Phenazine ethosulfate as a preferred electron acceptor to phenazine methosulfate in dye-linked enzyme assays.

Rapid nonenzymatic reduction of 2,6-dichlorophenolindophenol by N-methyl phenazonium methosulfate has been observed in aqueous solution and has been found to increase with increasing pH and ionic strength. The instability of N-methyl phenazonium methosulfate in aqueous solution has been explored in terms of change of absorption spectrum and formation of free radicals as evidenced by EPR spectroscopy. N-Ethyl phenazonium ethosulfate has been found to be much more stable than the methyl analog and did not reduce dichlorophenolindophenol nonenzymatically. The implications of these findings with respect to use of these dyes as artificial electron acceptors are discussed and the recommendation made that, wherever possible, use of N-methyl phenazonium methosulfate be discontinued in favor of use of the N-ethyl analog.     

Human nucleotide sequences related to the transforming gene of a murine sarcoma virus: studies with cloned viral and cellular DNAs

A recombinant plasmid, pI26, has been constructed by cloning into pBR322 a transforming gene of murine sarcoma virus (a Moloney strain, clone 124, MSV) synthesized by detergent-treated virions. From this plasmid a XbaI-HindIII fragment has been isolated which contains only mos-specific sequences. This mos-specific probe has been used for screening a human gene library cloned in bacteriophage λ Charon 4A. Of these, 19 clones have been isolated containing mos-related sequences. By physical mapping and molecular hybridization it has been shown that these sequences are neighboured by DNA regions related to Moloney murine leukemia virus. Recombinant phages have also been found containing human inserts related to MLV, not to the mos gene. The possible existence of murine-like endogenous retroviruses in the normal human genome, including that of a sarcoma type, is discussed. By Northern blotting, expression of the cellular c-mos gene has been detected in mouse liver treated with a hepatocarcinogen. The general significance of the suggested model for evaluating the relationship between chemical carcinogenesis and oncogene expression is discussed.