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Reassignment of the land tortoise haemogregarine Haemogregarina fitzsimonsi Dias 1953 (Adeleorina: Haemogregarinidae) to the genus Hepatozoon Miller 1908 (Adeleorina: Hepatozoidae) based on parasite morphology, life cycle and phylogenetic analysis of 18S rDNA sequence fragments.
No full textSUMMARY Research was undertaken to clarify the true taxonomic position of the terrestrial tortoise apicomplexan, Haemogregarina fitzsimonsi (Dias, 1953). Thin blood films were screened from 275 wild and captive South African tortoises of 6 genera and 10 species between 2009-2011. Apicomplexan parasites within films were identified, with a focus on H. fitzsimonsi. Ticks from wild tortoises, especially Amblyomma sylvaticum and Amblyomma marmoreum were also screened, and sporogonic stages were identified on dissection of adult ticks of both species taken from H. fitzsimonsi infected and apparently non-infected tortoises. Parasite DNA was extracted from fixed, Giemsa-stained tortoise blood films and from both fresh and fixed ticks, and PCR was undertaken with two primer sets, HEMO1/HEMO2, and HepF300/HepR900, to amplify parasite 18S rDNA. Results indicated that apicomplexan DNA extracted from tortoise blood films and both species of tick had been amplified by one or both primer sets. Haemogregarina fitzsimonsi 18S rDNA sequences from tortoise blood aligned with those of species of Hepatozoon, rather than those of species of Haemogregarina or Hemolivia. It is recommended therefore that this haemogregarine be re-assigned to the genus Hepatozoon, making Hepatozoon fitzsimonsi (Dias, 1953) the only Hepatozoon known currently from any terrestrial chelonian. Ticks are its likely vectors
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Occurrence of Hepatozoon canis (Adeleorina: Hepatozoidae) and Anaplasma spp. (Rickettsiales: Anaplasmataceae) in black-backed jackals (Canis mesomelas) in South Africa
Get PDFBackground:
Domestic dogs are not native to sub-Saharan Africa, which may account for their susceptibility to
Babesia rossi
, of which endemic black-backed jackals (
Canis mesomelas
) are natural reservoirs. There is virtually no
information on the occurrence of potentially pathogenic haemogregarines (e.g.
Hepatozoon canis
) or even rickettsial
bacteria (e.g.
Ehrlichia
spp. and
Anaplasma
spp.) in indigenous canids in sub-Saharan Africa. Such organisms could
pose a risk to domestic dogs, as well as to populations of endangered indigenous canid species.
Results:
Genomic DNA extracted from blood samples taken from 126 free-ranging and 16 captive black-backed
jackals was subjected to reverse line blot (RLB) hybridization assay; 82 (57.8%) specimens reacted only with the
Ehrlichia
/
Anaplasma
genera-specific probe. Full-length bacterial
16S
rRNA gene of five of these specimens was
cloned and the recombinants sequenced. The ten
16S
rDNA sequences obtained were most closely related, with
approximately 99% identity, to
Anaplasma
sp. South African Dog, various uncultured
Anaplasma
spp., as well as
various
Anaplasma phagocytophilum
genotypes. Ninety-one specimens were screened for haemogregarines
through PCR amplification using the
18S
rRNA gene; 20 (21.9%) specimens reacted positively, of which 14 (15.4%)
were confirmed positive for
Hepatozoon
genotypes from within
H. canis
. Two (2.2%) specimens were found positive
for two different
Hepatozoon
genotypes.
Conclusions:
Sequence analyses confirmed the presence of
16S
rDNA sequences closely related to
A. phagocytophilum
and
Anaplasma
sp. South African Dog as well as two
H. canis
genotypes in both free-ranging and captive black-backed
jackals. Distinguishing between closely related lineages may provide insight into differences in pathogenicity and
virulence of various
Anaplasma
and
H. canis
genotypes. By building up a more comprehensive understanding of the
range and diversity of the bacteria and eukaryotic organisms (piroplasms and haemogregarines) in the blood of
indigenous canids, we may gain insight to such infections in these often-endangered species and the potential for
horizontal transmission to and from domestic dogs via ticks where favourable conditions exis
Blood parasite biodiversity of reef-associated fishes of the eastern Caribbean
Get PDFParasitic micro-organisms can influence
multiple ecological processes, from growth, mortality,
and behavior, to community structure and trophic
interactions, yet are typically ignored components of
marine biodiversity. We collected 1298 blood samples
from reef fishes off 6 eastern Caribbean islands, representing
27 families, 57 genera and 103 species, in -
cluding invasive Indo-Pacific lionfish. Members of
14 species from 8 families were infected, comprising
damselfishes (Pomacentridae), parrotfishes (Scaridae),
mullet (Mugilidae), jacks (Caranjidae), Blennies (Blen -
neidae and Labrisomidae), snappers (Lutjanidae), and
angelfishes (Pomacanthidae). None of the 8 distinct
blood parasites found fit descriptions of other Ca -
ribbean parasites, but resembled typical Haemo gre -
garina-like intraerythrocytic parasites and Haemohormidium-
like parasites collected from fishes on the
Great Barrier Reef (GBR), Australia. No blood parasites
were found in lionfish and there was surprisingly little
overlap in the families of Caribbean and GBR fishes.
Most infected species were strongly diurnal. The high
incidence of infection in Stegastes damselfishes was
particularly surprising and has potentially important
ecological consequences, given that damselfishes influence
benthic community structure and are prey for
reef piscivores. Gnathiid isopods, an apparent vector
of apicomplexan blood parasites in other systems,
were common at sampling sites and collected for
use in transmission experiments. Haemogregarinalike
parasites were taken up by gnathiids that fed
on infected blennies. By comparison, when gnathiids
fed on Stegastes damselfish infected with a Hae mo -
hormidium-like parasite, no parasites were found.
This study reveals the high biodiversity of haemoparasites
infecting eastern Caribbean reef fishes, and
highlights the need for additional research throughout
the Caribbean and in other tropical reef systems
Ultrastructural comparison of Hepatozoon ixoxo and Hepatozoon theileri (Adeleorina: Hepatozoidae), parasitising South African Anurans
No full textTo date, only two haemogregarine parasite species have been described from
South African anurans: Hepatozoon ixoxo, infecting toads of the genus Scler-
ophrys (syn. Amietophrynus); and Hepatozoon theileri, parasitising the com-
mon river frog, Amietia quecketti. Both species have been characterised using
limited morphology, and molecular data from PCR amplified fragments of the
18S rRNA gene. However, no ultrastructural work has been performed thus
far. The aim of this study was to add descriptive information on the two spe-
cies by studying their ultrastructural morphology. Mature gamont stages, com-
mon in the peripheral blood of infected frogs, were examined by transmission
electron microscopy. Results indicate that H. ixoxo and H. theileri share typical
apicomplexan characteristics, but differ markedly in their external cellular struc-
ture. Hepatozoon ixoxo is an encapsulated parasite presenting a prominent cap
at the truncate pole, and shows no visible modifications to the host cell mem-
brane. In comparison, H. theileri does not present a capsule or cap, and pro-
duces marked morphological changes to its host cell. Scanning electron
microscopy was performed to further examine the cytopathological effects of
H. theileri, and results revealed small, knob-like protrusions on the erythrocyte
surface, as well as notable distortion of the overall shape of the host cel
Variations on the Author
Get PDF“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
Get PDFWe 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
Get PDFWe 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
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