Search results for "Systematics"
showing 10 items of 6702 documents
Comparative statistical studies on the physical anthropology of the late Medieval period (A.D. 1000–1500)
1984
Continuing previous studies on preceding temporal periods, a total of 162 skeletal series from the late Medieval period are analysed. The dendrogram reveals an east cluster as in the other periods but a west cluster is not evident possibly because western Europe is represented by very few series. Moreover, we find a Scandinavian and a Turk cluster. Regional or ethnic pooling of the original series gives an affinity structure which is more influenced by geographic proximity than by ethnic relation. This structure predominantly reflects differentiations of skull width and length and to a lesser degree of facial height. The diachronic trend appears again, but in this period there is only a sli…
Comparative statistical studies on the anthropology of the Iron Age (last millennium B.C.)
1975
Abstract Extending previous statistical studies on the anthropology of the Neolithic and Bronze Ages, anthropological material from the Iron Age (1000-0) was compiled and condensed into 71 series (population samples). Penrose distances were calculated on the basis of 10 skull measurements. The dendrogram consisting of 49 larger series shows a division into a west- and an east-cluster. The west-cluster can be broken down into a northern, entirely European section, and into a southern subcluster, stretching from Sardinia to Pakistan. The east-cluster differs from the west-cluster above all in the larger width measurements, as in the case with the north-east and south-west complexes in the Neo…
Correlation between serovars of Bacillus thuringiensis and type I beta-exotoxin production.
2003
beta-Exotoxin is a thermostable metabolite produced by some strains of Bacillus thuringiensis. Because of vertebrate toxicity, most commercial preparations of B. thuringiensis are prepared from isolates that do not produce beta-exotoxin. The aim of the present study was to find out the possible relationship between serovars of B. thuringiensis and beta-exotoxin production. A specific HPLC assay for type I beta-exotoxin has been used to detect this exotoxin in supernatants from final whole cultures of 100 strains belonging to four serovars of B. thuringiensis: thuringiensis, kurstaki, aizawai, and morrisoni. For each serovar, 25 strains randomly chosen from two Spanish collections were analy…
Distribution of cryl, cryll and cryV Genes within Bacillus thuringiensis Isolates from Spain
1999
Summary Using a PCR-based approach, a collection of 223 isolates of Bacillus thuringiensis from Spain was screened for the presence of cry genes belonging to three families. Genes from the cryI , cryII and cryV families were found in 54%, 42%, and 66% of the isolates, respectively. Only 23% of the isolates did not show the presence of any of the genes tested. Frequencies of these genes were compared in isolates from soil samples and from samples of cereal stores and mills, being this higher in the latter. Specific primers were used to detect cryIA(a), cryIA(b), cryIA(c), cryIA(d), cryIA(e), cryIB, cryIC, cryID, cryIE, cryIF and cryIG genes. Within the cryI family, the most frequent gene was…
Environmental distribution and diversity of Bacillus thuringiensis in Spain.
1998
Bacillus thuringiensis was isolated from 301 out of 1,005 samples collected in Spain from agricultural and non-cultivated soils, dust from stored products, and dead insects. Based on the production of parasporal crystals, 1,401 isolates were identified as B. thuringiensis after examining 11,982 B. thuringiensis-like colonies. We found a greater presence of B. thuringiensis in dust from grain storages than in other habitats. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the spore-crystal mixtures revealed diverse populations of B. thuringiensis which were differentiated in at least 92 distinct protein profiles. Serological identification also showed great diversity among the S…
A Polyphasic Approach to Study the Intraspecif ic Diversity Amongst Vibrio vulnificus Isolates
1997
Summary A polyphasic taxonomic approach using phenotypic and molecular genetic techniques, was carried out on the species Vibrio vulnificus in order to study its intraspecific diversity. Seven techniques, including phenotypic (API 20E, BIOLOG, total protein profiles, serotyping, ELISA), and genotypic methods (ribotyping and AFLP), were employed on 80 V. vulnificus strains of biotypes 1 and 2, including 9 reference cultures. The isolates came from different geographic origins (USA, Spain, Belgium, Sweden, Norway, Japan, Thailand) and types of samples (clinical, health/diseased fish, seafood, water). Diversity indexes calculated for strains of both biotypes revealed a higher phenotypic and ge…
Effectiveness of different vaccine formulations against vibriosis caused by Vibrio vulnificus serovar E (biotype 2) in European eels Anguilla anguilla
2001
Vibriosis due to Vibrio vulnificus serovar E (biotype 2) is one of the main causes of mortality in European eels cultured in Europe. The main objective of this study was to develop a vaccine and a vaccination procedure against this pathogen. With this aim, we tested several vaccine formulations (inactivated whole-cells with and without toxoids‹inactivated extracellular products‹from capsulated and uncapsulated strains, attenuated live vaccines and purified lipopolysaccharide [LPS]) on eels maintained under controlled laboratory conditions using different delivery routes (injection and immersion). To study the immune response we estimated antibody titers and bactericidal/bacteriostatic activ…
Field testing of a vaccine against eel diseases caused by Vibrio vulnificus
2001
The field results of a vaccination programme against Vibrio vulnificus serovar E (biotype 2) in a Spanish eel farm are reported. A total of 9.5 million glass eels were vaccinated from January 1998 to March 2000 by prolonged immersion followed by 2 subsequent reimmunisations after 12 to 14 and 24 to 28 d, respectively. The acquired protection and the immune response against serovar E were estimated over a period of 6 mo after vaccination. A similar vaccination schedule was conducted with elvers in a Danish eel farm. In this case, the acquired protection and the immune response against serovar E and the new eel-pathogenic serovars, recently described in Denmark, were evaluated over a short te…
Settling Down: The Genome of Serratia symbiotica from the Aphid Cinara tujafilina Zooms in on the Process of Accommodation to a Cooperative Intracell…
2014
Particularly interesting cases of mutualistic endosymbioses come from the establishment of co-obligate associations of more than one species of endosymbiotic bacteria. Throughout symbiotic accommodation from a free-living bacterium, passing through a facultative stage and ending as an obligate intracellular one, the symbiont experiences massive genomic losses and phenotypic adjustments. Here, we scrutinized the changes in the coevolution of Serratia symbiotica and Buchnera aphidicola endosymbionts in aphids, paying particular attention to the transformations undergone by S. symbiotica to become an obligate endosymbiont. Although it is already known that S. symbiotica is facultative in Acyrt…
Assessing the quality of service to customers provided by water utilities: A synthetic index approach
2017
Abstract Currently, water and sewer companies face the challenge of improving their quality of service to customers (QSC). Performance indicators are essential to monitor and benchmark the QSC of water companies; however, individual indicators do not provide a holistic evaluation of the quality of water and sewer services provided to customers. This study proposes an innovative QSC index based on distance-function techniques that makes it possible to compare changes in the QSC of water companies among locations and temporal periods. A case study assesses changes in QSC for a sample of Chilean water and sewer companies from 2007 to 2014. The results show that in spite of the efforts made by …