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J F De Jonckheere

Publications and source records attributed to J F De Jonckheere.

At least 19 recordsLinked to original sources
PubMed2003

Epidemiological typing of Acanthamoeba strains isolated from keratitis cases in Belgium.

From the corneas of nine keratitis patients and from their contact lenses, contact lens boxes and saline solutions, 15 strains of Acanthamoeba have been isolated. An Acanthamoeba strain was isolated from the swimming pool where one of the patients swam, while in the tapwater of the houses of three patients investigated, no Acanthamoeba could be detected. All the Acanthamoeba isolates from the cornea belong to genotype T4, but are different subtypes of T4. The Acanthamoeba detected on the contact lenses (and/or associated paraphernalia) of a patient are of the same subtype as that isolated from the cornea. The only Acanthamoeba strain isolated from a contact lens which was not related to an Acanthamoeba keratitis infection proved to be another genotype. A strain of Hartmannella from a cornea and two vahlkampfiids isolated from contact lenses had no connection with keratitis. This study confirms that, as found elsewhere, only Acanthamoeba genotype T4 of the 12 known Acanthamoeba genotypes is responsible for keratitis in Belgium. Most cases of Acanthamoeba keratitis cases are due to poor hygiene in the treatment (cleaning and storage) of contact lenses.

Acanthamoeba↗
PubMed2001

Phylogenetic relationships inferred from ribosomal its sequences and biogeographic patterns in representatives of the genus Calopteryx (Insecta: Odonata) of the West Mediterranean and adjacent West European zone.

Western Europe is a reinvasion zone for the riverine dragonfly genus Calopteryx (Insecta: Odonata). Reinvasion may have been from central West Asia or from the West Mediterranean refugium. Phylogenetic relationships of West Mediterranean and West European taxa of the genus Calopteryx from different localities were inferred from sequences of the internal transcribed spacers (ITS1 and ITS2) of the nuclear ribosomal RNA genes. Twenty-six taxa belonging to the species groups C. splendens, C. meridionalis, C. haemorrhoidalis, C. virgo, C. xanthostoma, and C. exul were analyzed, with two North American species, C. amata and C. aequabilis, as outgroup. Sequence data and phylogenetic analyses were used to infer biogeographical patterns. The ribosomal spacers (ITS1 and ITS2) and the intervening 5.8S rDNA gene were amplified by PCR and sequenced. The ITS2 sequences of the West Mediterranean and West European calopterygids show no length variation but the ITS1 region was slightly variable in length. The sequence variation for ITS1 and ITS2 regions between different West Mediterranean and West European calopterygids was 14.5 and 6.1%, respectively. Phylogenetic relationships inferred from ITS sequences only partly confirm morphological data. A monophyletic origin of all West Mediterranean and West European species emerged. They are separated into two main clades; the splendens-like forms and the virgo/meridionalis/haemorrhoidalis group. Intraspecific variability, indicating different stages of speciation, was detected only in West Mediterranean representatives (e.g., C. xanthostoma) but not in invasive representatives in West Europe. The North African endemic C. exul is more closely related to the Italian C. s. caprai than to C. splendens sensu strictu. Based on the present information, Cretan populations are the only splendens-like taxa in addition to C. s. caprai that deserve subspecies status.

Animals↗
PubMed2001

The amoeba-to-flagellate transformation test is not reliable for the diagnosis of the genus Naegleria. Description of three new Naegleria spp.

Trophozoites of several isolates from one location in Australia have failed consistently to transform into flagellates, although they display all other characteristics of the genus Naegleria. When changing the standard transformation test, flagellates were produced. In phylogenetic trees derived from partial small subunit ribosomal DNA (SSUrDNA) sequences, one of these strains branches close to a cluster comprising N. clarki, N. australiensis, N. italica and N. jadini. It is proposed that these Australian isolates represent a new species, named N. fultoni (strain NG885). Failing to form flagellates since their isolation, even when different transformation procedures are used, are two Naegleria strains from Chile and Indonesia. In SSUrDNA-based phylogenetic trees the Chilean strain clusters with N. pussardi and the Indonesian strain clusters with N. galeacystis, but the degree of sequence difference from these described species (3.5% and 2.2%, respectively) is sufficient to propose that both of the strains represent new species, named N. chilensis (strain NG946) and N. indonesiensis (strain NG945), respectively. The close relationships between each of the new species and the Naegleria species with which they cluster in SSUrDNA-based trees were confirmed by ribosomal internal transcribed spacer region (ITS) sequence comparisons. In France, several non-flagellating N. fowleri strains were isolated from one location. ITS rDNA sequence comparisons indicated that they correspond to a 'type' of N. fowleri found in both Europe and the USA. A redefinition of the genus Naegleria is proposed as a consequence of these and previous findings.

Amebiasis↗
PubMed2000

Ribosomal DNA sequences of Glugea anomala, G. stephani, G. americanus and Spraguea lophii (Microsporidia): phylogenetic reconstruction.

The microsporidian species Glugea anomala, G. stephani, G. americanus and Spraguea lophii were compared by using sequence data derived from their small subunit rDNA genes which were amplified by polymerase chain reaction and directly sequenced. These sequence data and published data of G. atherinae were analyzed and were used to infer a phylogenetic tree. The 5 microsporidian fish parasites appeared to be closely related. The higher sequence similarities demonstrated among G. anomala, G. stephani and G. atherinae suggest that these 3 parasites are in fact only 1 species of Glugea. Moreover, the higher sequence similarities between S. lophii and G. americanus support the transfer of the latter Glugea species into the genus Spraguea.

Animals↗
PubMed1999

Clustering of Acanthamoeba isolates from human eye infections by means of mitochondrial DNA digestion patterns.

A total of 90 Acanthamoeba isolates from human eye infections from 15 countries were clustered into distinct genotypes according to their mtDNA restriction fragment patterns. Closely related digestion phenotypes (sequence difference 0.1-1.5%) were integrated into a single genotype, whereas phenotypes with greater than 4.76% difference were considered distinct. Approximately 80% of the human isolates studied fell into 7 of 22 genotypes, indicating that virulence may be associated with specific clusters of cladistic groups of Acanthamoeba. This technique is useful for large-scale surveying of this particular pathogen.

Acanthamoeba↗
PubMed1998

Three different group I introns in the nuclear large subunit ribosomal DNA of the amoeboflagellate Naegleria.

We have amplified the large subunit ribosomal DNA (LSUrDNA) of the 12 described Naegleria spp. and of 34 other Naegleria lineages that might be distinct species. Two strains yielded a product that is longer than 3 kb, which is the length of the LSUrDNA of all described Naegleria spp. Sequencing data revealed that the insert in one of these strains is a group I intron without an open reading frame (ORF), while the other strain contains two different group I introns, of which the second intron has an ORF of 175 amino acids. In the latter ORF there is a conserved His-Cys box, as in the homing endonucleases present in group I introns in the small subunit ribosomal DNA (SSUrDNA) of Naegleria spp. Although the group I introns in the LSUrDNA differ in sequence, they are more related to each other than they are to the group I introns in the SSUrDNA of Naegleria spp. The three group I introns in the LSUrDNA in Naegleria are at different locations and are probably acquired by horizontal transfer, contrary to the SSUrDNA group I introns in this genus which are of ancestral origin and are transmitted vertically.

Animals↗
PubMed1998

Genetic variation in the free-living amoeba Naegleria fowleri.

In this study, 30 strains of the pathogenic free-living amoeba Naegleria fowleri were investigated by using the randomly amplified polymorphic DNA (RAPD) method. The present study confirmed our previous finding that RAPD variation is not correlated with geographical origin. In particular, Mexican strains belong to the variant previously detected in Asia, Europe, and the United States. In France, surprisingly, strains from Cattenom gave RAPD patterns identical to those of the Japanese strains. In addition, all of these strains, together with an additional French strain from Chooz, exhibited similarities to South Pacific strains. The results also confirmed the presence of numerous variants in Europe, whereas only two variants were detected in the United States. The two variants found in the United States were different from the South Pacific variants. These findings do not support the previous hypothesis concerning the origin and modes of dispersal of N. fowleri.

Animals↗
PubMed1997

Differences in isoenzyme patterns of axenically and monoxenically grown Acanthamoeba and Hartmannella.

Axenically and monoxenically grown Acanthamoeba castellanii, Acanthamoeba polyphaga and different isolates of Hartmannella vermiformis strains were examined by polyacrylamide isoelectric focusing in the pH range 3-10. Isoenzyme patterns of acid phosphatase (AP), propionyl esterase (PE), malate dehydrogenase (MDH), alcohol dehydrogenase (ADH), glucose phosphate isomerase (GPI) and phosphoglucomutase (PGM) were compared. Zymograms were used to reveal differences in typical isoenzyme patterns between axenically and monoxenically grown amoebae and to compare axenically grown A. castellanii, A. polyphaga and H. vermiformis. Comparison of zymograms for AP, PE and MDH between axenically grown Acanthamoeba and Hartmannella strains revealed different isoenzyme patterns. Acanthamoeba showed strong bands for ADH and extremely weak bands for GPI and PGM, while Hartmannella lacked ADH but possessed bands for GPI and PGM. Comparison of zymograms from axenically and monoxenically grown amoebae revealed a lower intensity and even lack of typical isoenzyme bands in lysates from monoxenic cultures. The observed changes in typical isoenzyme patterns induced by the bacterial substrate can influence the correct isoenzymatic typing of different strains in clinical and phylogenetic studies.

Acanthamoeba↗
PubMed1994

Loss of the ORF in the SSUrDNA group I intron of one Naegleria lineage.

We have found a Naegleria lineage in which the SSUrDNA contains a group I intron with a length of 375 nucleotides. This is a unique finding because all group I introns detected until now in Naegleria are 1.3 kilobases long and contain an open reading frame coding for 245 amino acids. Sequence data show that the 375 nucleotide-long intron is at the same place in the SSUrDNA as, and is descendant from, the 1.3 kilobase group I intron present in other species of Naegleria. Our data indicate that in one lineage of Naegleria the group I intron lost part of its DNA that is not contributing to the secondary structure but that carries the open reading frame. The amoeboflagellate genus Naegleria contains strains without the intron and strains with the intron, with or without an open reading frame. Therefore, this genus provides a unique opportunity to study the function and evolution of both the group I intron and the open reading frame.

Animals↗
PubMed1994

Riboprinting of Naegleria spp.: small-subunit versus large-subunit rDNA.

The nonpathogenic amoeba Naegleria lovaniensis is closely related to the human pathogen N. fowleri. Both grow at a maximal temperature of 45 degrees C and, therefore, are often found together in the environment. As they are morphologically inseparable at the light-microscope level, refined techniques are necessary to separate the two species. I have used restriction-fragment-length polymorphism analysis of the polymerase chain reaction (PCR)-amplified ribosomal RNA gene, or riboprinting, to distinguish between the different Naegleria spp. Riboprints generated from the small subunit and the large subunit separate N. fowleri from N. lovaniensis. To examine the taxonomic relationships among all Naegleria spp., analysis of the large subunit has to be performed; the small subunit contains a 1.3-kb group I intron, which interferes with tree building based upon restriction sites.

Animals↗
PubMed1993

Five cases of primary amebic meningoencephalitis in Mexicali, Mexico: study of the isolates.

Five Naegleria strains isolated from patients with primary amebic meningoencephalitis and one strain isolated from the water of an artificial canal were investigated. All strains were pathogenic for mice when instilled intranasally and showed cytopathic effects in Vero cell cultures. Their growth characteristics (isolation and subculture at 45 degrees C), serological results, and isoenzyme patterns permitted us to identify the six strains as Naegleria fowleri. This is the first time that Naegleria fowleri has been isolated from patients with primary amebic meningoencephalitis in Mexico.

Acid Phosphatase↗
PubMed1992

Restriction-fragment-length polymorphism and variation in electrophoretic karyotype in Naegleria fowleri from Japan.

Strains of Naegleria fowleri isolated in Japan from two different places were found to differ in electrophoretic karyotype and restriction-fragment-length polymorphism (RFLP) both from each other and from strains isolated on other continents. Using the Wagner parsimony method on the RFLP, we found that the Japanese isolates are most closely related to the Australian isolates and most distinct from the European isolates.

Animals↗
PubMed1992

Appearance in Europe of Naegleria fowleri displaying the Australian type of restriction-fragment-length polymorphism.

We report for the first time the isolation in Europe of Naegleria fowleri showing a type of restriction-fragment-length polymorphism (RFLP) usually found in Australia. The presence of this type as well as the European type fluctuated with time in the cooling waters of the nuclear power station investigated. Two possible explanations for the appearance of the Australian N. fowleri type in Europe are presented.

Animals↗