1,720,959 research outputs found
Vaccination approaches against opportunistic fungal infections caused by Aspergillus fumigatus.
No full textAlthough innate immunity primarily combats systemic infections of opportunistic fungi such as Aspergillus and Candida spp., acquired and protective immunoreactions were observed long ago in animal trials following sublethal systemic infections caused by viable fungi or after challenging animals with inactivated fungal cells. Based on these observations, fungal antigens should exist which mediate such protective immunoreactions and have in part already been identified. In this context, this review focuses primarily on the various approaches that have been used to identify protection-mediating Aspergillus-antigens and their rationale. Emphasis is placed on screening methods that have exploited genetic or proteomic approaches on the basis of the corresponding fungal genome projects. Thereby, a survey and description is given of the antigens so far known to be capable of inducing immune responses that protect animals against acquiring lethal systemic aspergillosis
Campylobacter jejuni - The Search for virulence-associated factors
No full textIn recent years Campylobacter jejuni replaced Salmonella spp. as the most common bacterial cause of food-borne gastroenteritis worldwide. Noticeable is the fact that no classical enterotoxins are known for C. jejuni. The sequencing of the complete genome revealed that C. jejuni possesses one single trimeric cytotoxin, called cytolethal distending toxin (CdtABC). Other previously suspected toxins could not be confirmed by sequence analysis. However, a number of alternative virulence-associated factors have been identified so far. The multidrug efflux pump CmeABC faciliates, by "neutralization" of bile salts, the survival of C. jejuni in the avian as well as in the human intestine. Furthermore it is responsible for resistance to heavy metal ions and to certain antibiotics. The flagellum of C. jejuni mediates not only the targeted motility directed by three families of chemo- and aerotaxis receptors. A homologue of a type-III-secretion-system integrated in the flagellar apparatus is functionally involved in the cell-invasion process. Thus, a whole group of proteins termed Campylobacter invasion antigens (Cia) is injected into the host cell via the flagellar transport mechanism during the process of host cell invasion. Further pathogenicity-associated determinants are the polysaccharide capsule and specific glycosylation of the lipooligosaccharide (LOS). It has been shown that C. jejuni strains with sialylation of the lipooligosaccharide display increased invasiveness. These strains are also responsible for the development of the Guillain-Barre-syndrome, through molecular mimicry with gangliosides of the central nervous system. In the past, many colonization-related factors have been identified with the help of transposon-induced mutagenesis and chicken colonization models. Using this and other modern molecular biology methods, combined with appropriate animal models such as gnotobiotic mice in which symptomatic campylobacteriosis can be established, it is hoped to identify additional virulence-associated factors
Epidemiological Association of Different <i>Campylobacter jejuni</i> Groups with Metabolism-Associated Genetic Markers
No full textABSTRACT
In this study, multilocus sequence typing (MLST) was combined with the genetic detection of six genetic markers,
ansB
,
dmsA
,
ggt
,
cj1585c
,
cjj81176
-
1367/71
(
cj1365c
), and the two-gene marker
tlp7
(
cj0951c
plus
cj0952c
), to assess if their presence correlated with different
C. jejuni
clonal groups. Using a collection of 266
C. jejuni
isolates from (in decreasing order of sample size) humans, chickens, cattle, and turkeys, it was further investigated whether the resulting genotypes correlated with the isolation source. We found combinations of the six marker genes to be mutually exclusive, and their patterns of presence or absence correlated to some degree with animal source. Together with MLST results, the obtained genotypes could be segregated into six groups. An association was identified for
ansB
,
dmsA
, and
ggt
with the MLST-clonal complexes (MLST-CC) 22, 42, 45, and 283, which formed the most prominent group, in which chickens were the most prevalent animal source. Two other groups, characterized by the presence of
cj1585c
,
cjj81176
-
1367/71
, and the two-gene marker
tlp7
, associated with either MLST-CC 21 or 61, were overrepresented in isolates of bovine origin. Mutually exclusive marker gene combinations were observed for
ansB
,
dmsA
, and
ggt
, typically found in CC 45 and the related CC 22, 42, and 283, whereas the other three marker genes were found mostly in CC 21, 48, and 206. The presence of the two-gene marker
tlp7
, which is typical for MLST 21 and 53 as well as for MLST-CC 61, strongly correlates with a bovine host; this is interpreted as an example of host adaptation. In cases of
C. jejuni
outbreaks, these genetic markers could be helpful for more effective source tracking.
</jats:p
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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