ABSTRACT
Bacterial symbionts that resembled mollicutes were discovered in the marine bryozoan
Watersipora arcuata
in the 1980s. In this study, we used PCR and sequencing of 16S rRNA genes, specific fluorescence in situ hybridization, and phylogenetic analysis to determine that the bacterial symbionts of “
W. subtorquata
” and “
W. arcuata
” from several locations along the California coast are actually closely related α-
Proteobacteria
, not mollicutes. We propose the names
“Candidatus
Endowatersipora palomitas” and “
Candidatus
Endowatersipora rubus” for the symbionts of “
W. subtorquata
” and “
W. arcuata
,” respectively.
ABSTRACT
Members of the genus
Arsenophonus
comprise a large group of bacterial endosymbionts that are widely distributed in arthropods of medical, veterinary, and agricultural importance. At present, little is known about the role of these bacteria in arthropods, because few representatives have been isolated and cultured in the laboratory. In the current study, we describe the isolation and pure culture of an
Arsenophonus
endosymbiont from the hippoboscid louse fly
Pseudolynchia canariensis
. We propose provisional nomenclature for this bacterium in the genus
Arsenophonus
as “
Candidatus
Arsenophonus arthropodicus.” Phylogenetic analyses indicate that “
Candidatus
Arsenophonus arthropodicus” is closely related to the
Arsenophonus
endosymbionts found in psyllids, whiteflies, aphids, and mealybugs. The pure culture of this endosymbiont offers new opportunities to examine the role of
Arsenophonus
in insects. To this end, we describe methods for the culture of “
Candidatus
Arsenophonus arthropodicus” in an insect cell line and the transformation of this bacterium with a broad-host-range plasmid.
ABSTRACT
Zoothamnium niveum
is a giant, colonial marine ciliate from sulfide-rich habitats obligatorily covered with chemoautotrophic, sulfide-oxidizing bacteria which appear as coccoid rods and rods with a series of intermediate shapes. Comparative 16S rRNA gene sequence analysis and fluorescence in situ hybridization showed that the ectosymbiont of
Z. niveum
belongs to only one pleomorphic phylotype. The
Z. niveum
ectosymbiont is only moderately related to previously identified groups of thiotrophic symbionts within the
Gammaproteobacteria
, and shows highest 16S rRNA sequence similarity with the free-living sulfur-oxidizing bacterial strain ODIII6 from shallow-water hydrothermal vents of the Mediterranean Sea (94.5%) and an endosymbiont from a deep-sea hydrothermal vent gastropod of the Indian Ocean Ridge (93.1%). A replacement of this specific ectosymbiont by a variety of other bacteria was observed only for senescent basal parts of the host colonies. The taxonomic status “
Candidatus
Thiobios zoothamnicoli” is proposed for the ectosymbiont of
Z. niveum
based on its ultrastructure, its 16S rRNA gene, the intergenic spacer region, and its partial 23S rRNA gene sequence.
ABSTRACT
Wild deer are one of the important natural reservoir hosts of several species of
Ehrlichia
and
Anaplasma
that cause human ehrlichiosis or anaplasmosis in the United States and Europe. The primary aim of the present study was to determine whether and what species of
Ehrlichia
and
Anaplasma
naturally infect deer in Japan. Blood samples obtained from wild deer on two major Japanese islands, Hokkaido and Honshu, were tested for the presence of
Ehrlichia
and
Anaplasma
by PCR assays and sequencing of the 16S rRNA genes, major outer membrane protein
p44
genes, and
groESL
. DNA representing four species and two genera of
Ehrlichia
and
Anaplasma
was identified in 33 of 126 wild deer (26%). DNA sequence analysis revealed novel strains of
Anaplasma phagocytophilum
, a novel
Ehrlichia
sp.,
Anaplasma centrale
, and
Anaplasma bovis
in the blood samples from deer. None of these have been found previously in deer. The new
Ehrlichia
sp.,
A. bovis
, and
A. centrale
were also detected in
Hemaphysalis longicornis
ticks from Honshu Island. These results suggest that enzootic cycles of
Ehrlichia
and
Anaplasma
species distinct from those found in the United States or Europe have been established in wild deer and ticks in Japan.
ABSTRACT
Molecular analysis of bacteria enriched under in situ-like conditions and mechanically isolated by micromanipulation showed that a hitherto-uncultivated microaerophilic bacterium thriving in oxygen-sulfide counter-gradients (R. Thar and M. Kühl, Appl. Environ. Microbiol. 68:6310-6320, 2000) is affiliated with the ε-subdivision of the
Proteobacteria
. The affiliation was confirmed by the use of whole-cell hybridization with newly designed specific oligonucleotide probes. The bacterium belongs to a new genus and received the provisional name “
Candidatus
Thioturbo danicus.”
ABSTRACT
Huanglongbing (yellow dragon disease) is a destructive disease of citrus. The etiological agent is a noncultured, phloem-restricted alpha-proteobacterium, “
Candidatus
Liberibacter africanus” in Africa and “
Candidatus
Liberibacter asiaticus” in Asia. In this study, we used an
omp
-based PCR-restriction fragment length polymorphism (RFLP) approach to analyze the genetic variability of “
Ca
. Liberibacter asiaticus” isolates. By using five different enzymes, each the 10 isolates tested could be associated with a specific combination of restriction profiles. The results indicate that the species “
Ca
. Liberibacter asiaticus,” even within a given region, may comprise several different variants. Thus,
omp
-based PCR-RFLP analysis is a simple method for detecting and differentiating “
Ca
. Liberibacter asiaticus” isolates.
ABSTRACT
The cells and tissues of many aphids contain bacteria known as “secondary symbionts,” which under specific environmental circumstances may be beneficial to the host insect. Such symbiotic bacteria are traditionally described as intractable to cultivation in vitro. Here we show that two types of aphid secondary symbionts, known informally as T type and U type, can be cultured and maintained in three insect cell lines. The identities of the cultured bacteria were confirmed by PCR with sequencing of 16S rRNA gene fragments and fluorescence in situ hybridization. In cell lines infected with bacteria derived from aphids harboring both T type and U type, the U type persisted, while the T type was lost. We suggest that the two bacteria persist in aphids because competition between them is limited by differences in tropism for insect tissues or cell types. The culture of these bacteria in insect cell lines provides a new and unique research opportunity, offering a source of unibacterial material for genomic studies and a model system to investigate the interactions between animal cells and bacteria. We propose the provisional taxon names “
Candidatus
Consessoris aphidicola” for T type and “
Candidatus
Adiaceo aphidicola” for U type.