The effect of cooling rate, freeze-drying suspending fluid and culture age on the preservation of Campylobacter pylori

The effects of freezing rate, suspending fluid and age of culture on the ability of four strains of Campylobacter pylori to survive and recover from freeze-drying were examined. Freeze-drying by standard procedures generally resulted in an overall loss in viability of between 3 and 7 log units. The exact cause of poor recovery by C. pylori was not established but strain differences were detected, with NCTC 11637 (type strain) surviving better than NCTC 11638 and NCTC 11639. Recovery of the poorest growing strain (NE 26695) was notably more erratic. The largest loss in viability occurred at the primary drying stage. Losses resulting from freezing and secondary drying were less marked and the rate of freezing had only a marginal effect on recovery. Nineteen different freeze-drying suspending fluids were investigated. Overall the best recovery results were obtained with 5% inositol-broth (or horse serum) plus 25% glucose, at pH 7.0, in which loss of viability was typically about 4 log units. Other factors, such as age of culture and number of viable bacteria in the before-dry suspension, did not have a significant effect on survival. We conclude from these results that C. pylori can survive freeze-drying, albeit in small numbers, but the degree of recovery is apparently largely strain dependent.     

Physiological Characterizations of Acanthamoeba Strains

ABSTRACT. Thirty-seven strains of Acanthamoeba are described using 69 physiological characters. The characterizations of the strains are based on quantitative estimates of growth responses which were standardized to eliminate any effects of differences in growth rates of the strains. Thirty-six distinct patterns are generated using numerical profiles, but it is possible to distinguish within this total diversity 20 sub-generic groups which, although not completely congruent with the morphological species, are consistent with other non-morphological characters. Evidence is presented that Acanthamoeba is a coherent, well-founded genus, but it is not desirable to recognize formal taxa at the sub-generic level.     

Seed dispersal and germination behavior of three threatened endemic labiates of Cyprus

The present study examined seed dispersal and germination in three of the most threatened endemic labiates of Cyprus: Origanum cordifolium , Phlomis brevibracteata and Phlomis cypria ssp. occidentalis . Some common traits in these taxa can be correlated with their overall survival strategy. Seeds mature in mid to late summer, but most seeds remain on the mother plants until the beginning of the rainy season. The opening of the calyces containing the seeds seems to be caused by absorption of moisture. Water is also the most important dispersal factor because the seeds are dispersed by rain. Seed germination occurs at relatively low temperatures that prevail in the field at the beginning of the rainy season. This behavior provides the plants with ecological advantages because their seeds are exposed on the soil at the most appropriate period (mid to late autumn) for germination and seedling survival. The present study contributes substantially to in situ and ex situ conservation of these threatened plants.     

Biogeography and pattern of gene flow among Barbus species (Teleostei: Cyprinidae) inhabiting the Italian Peninsula and neighbouring Adriatic drainages as revealed by allozyme and mitochondrial sequence data

Genetic relationships among 24 Italian and Adriatic populations of barbs (genus Barbus ) were assessed using electrophoretic analysis of allozymes and mitochondrial DNA sequences of the cytochrome b gene. Results obtained with both markers were concordant, but they were not congruent with the current morphology-based systematics and taxonomy. Populations assigned to the same nominal taxa ( B. caninus , B. petenyi and B. rebeli ), were very divergent in both allozymes and mtDNA, indicating that these populations deserve recognition as different units for conservation and management. On the other hand, the two fluvio-lacustrine taxa considered as distinct species (i.e. B. plebejus and B. tyberinus ) are genetically very close to each other, showing no clear differences at either allozymes or mtDNA. The population of B. caninus from Pellice River carried allozyme alleles and mtDNA specific for B. plebejus , indicating a genetic introgression towards the former species. © 2002 The Linnean Society of London, Biological Journal of the Linnean Society , 2002, 75 , 83–99.     

Rapid radiation of the Mediterranean Luciobarbus species (Cyprinidae) after the Messinian salinity crisis of the Mediterranean Sea, inferred from mitochondrial phylogenetic analysis

Phylogenetic relationships of 64 freshwater Barbus s.s. species distributed in basins around the Mediterranean Sea were assessed using cytochrome b sequences. Our results are in concordance with previous morphological and genetic studies, which proposed that these species belong to two major lineages (or subgenera): Barbus and Luciobarbus . We were particularly interested in phylogenetic relationships among species of the Luciobarbus lineage that are primarily found in the southern Mediterranean region from the Iberian Peninsula to the Middle East. In the Luciobarbus lineage, species that were previously attributed to the Capoeta genus were clustered. In this study, we observed short internodes between monophyletic groups having a geographical agreement around the Mediterranean. However, groups from the opposite sides of the Mediterranean Sea (Iberian Peninsula– Capoeta , north-western Africa–Middle East) seem to be phylogenetically close. We therefore infer that rapid radiation of Luciobarbus species in the Late Miocene better fits our data rather than gradual founder events in the southern Mediterranean. We propose that the biogeographical event along an east–west route, responsible for the present distribution of Luciobarbus species, was the 'Lago Mare' phase of the Mediterranean Sea that provided a rapid dispersal route over extensive distances. This provides new insights into the speciation pattern of this group, and may be of general use in the study of freshwater species in these regions.  © 2003 The Linnean Society of London, Biological Journal of the Linnean Society , 2003, 80 , 207–222.     

HOME PLACEMENT TESTING OF LAMB CONDUCTED IN SIX COUNTRIES

Consumer placement tests, which are used to assess products in an appropriate context, were performed in 36 households comprising 2 to 8 persons in England, France, Greece, Iceland, Italy and Spain using leg joints from 2 types of lamb raised in each of those countries. Ratings of odor, tenderness, juiciness, flavor and overall liking were different among lamb types and overall, the least tender was the least liked. Variations in ratings of cooking odor given by the cook only, which were most marked by the Greek and Spanish panels, were correlated with assessments of the other qualities given by the whole household. Variations in liking were less among individuals within a household than between households and reduced as the number of individuals in a household increased. The structure of a panel is important and should be taken into account when analyzing and concluding from consumer placement tests.     

Enzyme Composition and the Taxonomy of Acanthamoeba

The enzyme activities of 37 representative strains of Acanthamoeba against 19 substrates have been examined. A total of 13 enzyme complements were identified, which could be arranged in six larger groups. There was good agreement between these groupings and the arrangement of the strains that was suggested by the electrophoresis patterns of their esterases and acid phosphatases. A nomericlature is described which provides an unequivocal numerical label for each enzyme complement.     

Genetic variation in populations of the endangered fish Ladigesocypris ghigii and its implications for conservation

1. The genetic variation of the endangered freshwater fish Ladigesocypris ghigii, endemic to the island of Rhodes (Greece), was investigated for nine populations, originating from seven different stream systems and a reservoir, both at the mtDNA and nuclear level, in order to suggest conservation actions. 2. Both restriction fragment length polymorphism analysis of five segments of mitochondrial DNA (ND‐5/6, COI and 12S‐16S rRNA) amplified by polymerase chain reaction, and random amplified polymorphic DNA analysis, revealed extremely low levels of intra‐population polymorphism. It is highly likely that the low intra‐population variability is the result of successive bottleneck events evident in shrinkage and expansion of the populations year after year, which may have led to a complete loss of several genotypes and haplotypes, and an increased degree of inbreeding. 3. Inter‐population genetic structuring was high, with fixation of haplotypes within six of the nine populations and fixation of alleles within populations originating from different waterbodies. It is probable that all haplotypes and/or alleles found were initially represented in all populations. However, because of the long time of isolation coupled with successive bottleneck and subsequent genetic drift, common mtDNA haplotypes and alleles among the populations may have become rare or extinct through stochastic lineage loss. 4. Although nucleotide divergence among haplotypes was very shallow, half of the haplotypes recorded (three of six), resulted from nucleotide changes on the 12S–16S rRNA segments, which are the most conserved part of the mitochondrial genome. This fact may indicate that the observed genetic variation did not necessarily result only from the retention of ancestral polymorphism, but may have arisen through mutation and complete lineage sorting over a relatively small number of generations, once the populations had become isolated from one another. 5. Our data suggest that two of the L. ghigii populations may be on independent evolutionary trajectories. Considering that each population appears so far well adapted within each site, all populations should be managed and conserved separately.