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Koichi Koyama - One of the best experts on this subject based on the ideXlab platform.
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bacteria induced hatching of trichuris muris eggs occurs without direct contact between eggs and bacteria
Parasitology Research, 2016Co-Authors: Koichi KoyamaAbstract:Using three isolates of the murine parasitic nematode Trichuris muris, E, E/J (the E isolate maintained in Japan), and S, I have previously demonstrated that when the Embryonated eggs of the E/J and E isolates are incubated with the intestinal bacteria Escherichia coli and Staphylococcus aureus, they are induced to hatch in vitro. However, the eggs of the S isolate are unresponsive to these bacteria. In the present study, I investigated whether direct contact between the Embryonated eggs of the E/J and E isolates and bacteria is required to induce their hatching. To do so, a new co-culture system for eggs and bacteria (E. coli or S. aureus) was developed to block any direct contact between the eggs and the bacteria. In the hatching experiment using the new system, when direct contact between the eggs and bacteria was completely prevented, the eggs still hatched. However, the peak levels of hatching without direct contact were about 20 % lower than those with direct contact, and peak hatching occurred later without direct contact. This evidence suggests that hatching occurs without direct contact between the eggs and bacteria, and that unidentified material derived from active bacteria induces the hatching of Embryonated eggs of the E/J and E isolates of T. muris in vitro.
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erratum to bacteria induced hatching of trichuris muris eggs occurs without direct contact between eggs and bacteria
Parasitology Research, 2016Co-Authors: Koichi KoyamaAbstract:Using three isolates of the murine parasitic nematode Trichuris muris, E, E/J (the E isolate maintained in Japan), and S, I have previously demonstrated that when the Embryonated eggs of the E/J and E isolates are incubated with the intestinal bacteria Escherichia coli and Staphylococcus aureus, they are induced to hatch in vitro. However, the eggs of the S isolate are unresponsive to these bacteria. In the present study, I investigated whether direct contact between the Embryonated eggs of the E/J and E isolates and bacteria is required to induce their hatching. To do so, a new co-culture system for eggs and bacteria (E. coli or S. aureus) was developed to block any direct contact between the eggs and the bacteria. In the hatching experiment using the new system, when direct contact between the eggs and bacteria was completely prevented, the eggs still hatched. However, the peak levels of hatching without direct contact were about 20 % lower than those with direct contact, and peak hatching occurred later without direct contact. This evidence suggests that hatching occurs without direct contact between the eggs and bacteria, and that unidentified material derived from active bacteria induces the hatching of Embryonated eggs of the E/J and E isolates of T. muris in vitro.
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Evidence for bacteria-independent hatching of Trichuris muris eggs
Parasitology Research, 2013Co-Authors: Koichi KoyamaAbstract:Hatching of infective larvae from Embryonated eggs in the intestine is an essential first step in Trichuris infections. There are three isolates of the murine parasitic nematode Trichuris muris : E, E-J (the E isolate maintained in Japan), and S. Incubation of T . muris Embryonated eggs with the intestinal bacteria Escherichia coli and Staphylococcus aureus induced in vitro hatching of the eggs, but Enterococcus faecalis failed to induce hatching. Bacteria-induced in vitro hatching of Embryonated eggs occurred in the E and E-J isolates, whereas the S isolate was unresponsive to bacteria. T . muris worms recovered from infected mice showed no significant difference between the E-J and S isolates in their infectivity to susceptible B10.BR mice ( P > 0.05). In vivo hatching of Embryonated eggs occurred at 30 min post-infection in the upper and lower halves of the small intestine of ddY mice infected with the E-J or S isolates, and on average, 65 % of Embryonated eggs recovered from the upper half of the small intestine were hatched in both the E-J and S isolates. In comparison with Enterococcus , the bacteria E . coli and S . aureus represent relatively minor components of the flora of the upper half of the small intestine of mice. These observations point to the possibility that bacteria-independent hatching might also occur in vivo, at least for the S isolate, and imply the existence of a very different system of induction of hatching in vivo.
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characteristics and incidence of large eggs in trichuris muris
Parasitology Research, 2013Co-Authors: Koichi KoyamaAbstract:The production of small numbers of large eggs among the standard-sized eggs of Trichuris trichiura is well known. Large eggs have also been observed in Trichuris muris, but they have not been studied previously. This paper compares the characteristics of the large eggs (LEs, ≥74.5 μm long) and standard-sized eggs (SEs, <74.5 μm long) in cultures of T. muris. Among 112,554 cultured eggs, LEs occurred at very low frequency (0.03 %, i.e., about three large eggs per 104 cultured eggs). Embryonated eggs represented 93.72 % of SEs, but only 25.00 % of LEs were Embryonated. Embryonated LEs and SEs contained fully matured larvae. An atypical category of unEmbryonated egg, which contained an incompletely developed larva, an abnormal larva, or granular components, was common among the LEs. However, similar atypical unEmbryonated SEs were rarely observed. These observations suggest that the LEs that occur very infrequently in T. muris result from an abnormality of embryonation (larval development).
J.l. Guillén - One of the best experts on this subject based on the ideXlab platform.
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Cross-reactions of sera from Toxascaris leonina and Ascaris suum infected mice with Toxocara canis, Toxascaris leonina and Ascaris suum antigens
International journal for parasitology, 1995Co-Authors: Carmen Cuéllar, S. Fenoy, J.l. GuillénAbstract:Abstract The ELISA method using larval ES products and homogenized Toxocara canis, Toxascaris leonina and Ascaris suum adult worms extract, was used to determine the possible cross-reactions in BALB c and C57BL 10 mice inoculated with Embryonated eggs or adult worms extract of T. leonina or A. suum in single and multiple doses. When we used sera of mice infected with Embryonated eggs of T. leonina against different heterologous Ag, no cross-reactions against T. canis ES and A. suum ES Ag were observed using a single dose. Similarly, in multiple doses no response against T. canis ES Ag was observed. In mice inoculated with adult worms extract of T. leonina cross-reactions with T. canis ES and A. suum ES Ag did not occur. Sera from BALB c mice infected with Embryonated eggs of A. suum, was tested using ES Ag from both A. suum and T. canis and no reactions were observed. This fact confirmed the resistance of this murine strain to A. suum Embryonated eggs. When we used sera of susceptible C57BL 10 mice infected against different heterologous Ag, we observed no cross-reactions against T. canis ES Ag. In the case of both BALB c and C57BL 10 mice immunized with a single dose of A. suum adult crude extract no cross-reactions were seen against ES T. canis Ag and with sera from C57BL 10 mice against ES T. leonina. These facts confirmed the specificity of the ES T. canis Ag.
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Cross-reactions of sera from Toxocara canis-infected mice with Toxascaris leonina and Ascaris suum antigens.
International journal for parasitology, 1992Co-Authors: Carmen Cuéllar, S. Fenoy, J.l. GuillénAbstract:Abstract The ELISA method using larval excretory-secretory (E/S) products and homogenized Toxocara canis, Toxascaris leonina and Ascaris suum adult worm extract were used to determine possible crossreactions in BALB/c and C57BL/10 mice, inoculated with Embryonated eggs or adult worm extract of T. canis in single and multiple doses. When we used sera of mice infected with Embryonated eggs of T. canis against different heterologous antigens, we observed no cross-reactions in BALB/c mice against A. suum E/S and adult worm extract antigens with a single dose. In multiple doses this was absent too against T. leonina adult worm extract in BALB/c mice, and in both strains against A. suum E/S and adult worm extract. In BALB/c mice inoculated with adult worm extract of T. canis we did not observe cross-reactions with A. suum E/S antigen with both inoculation doses. In the remainder of the experiments, we observed cross-reactions of different intensities.
Ernest Winocour - One of the best experts on this subject based on the ideXlab platform.
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adeno associated virus type 2 enhances goose parvovirus replication in Embryonated goose eggs
Virology, 2005Co-Authors: Mertyn Malkinson, Ernest WinocourAbstract:The autonomous goose parvovirus (GPV) and the human helper-dependent adeno-associated virus type 2 (AAV2) share a high degree of homology. To determine if this evolutionary relationship has a biological impact, we studied viral replication in human 293 cells and in Embryonated goose eggs coinfected with both viruses. Similar experiments were performed with the minute virus of mice (MVM), an autonomous murine parvovirus with less homology to AAV2. In human 293 cells, both GPV and MVM augmented AAV2 replication. In contrast, AAV2 markedly enhanced GPV replication in Embryonated goose eggs under conditions where a similar effect was not observed with MVM. AAV2 did not replicate in Embryonated goose eggs and AAV2 inactivated by UV-irradiation also enhanced GPV replication. To our knowledge, this is the first report that a human helper-dependent member of the Parvoviridae can provide helper activity for an autonomous parvovirus in a natural host.
Carmen Cuéllar - One of the best experts on this subject based on the ideXlab platform.
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Cross-reactions of sera from Toxascaris leonina and Ascaris suum infected mice with Toxocara canis, Toxascaris leonina and Ascaris suum antigens
International journal for parasitology, 1995Co-Authors: Carmen Cuéllar, S. Fenoy, J.l. GuillénAbstract:Abstract The ELISA method using larval ES products and homogenized Toxocara canis, Toxascaris leonina and Ascaris suum adult worms extract, was used to determine the possible cross-reactions in BALB c and C57BL 10 mice inoculated with Embryonated eggs or adult worms extract of T. leonina or A. suum in single and multiple doses. When we used sera of mice infected with Embryonated eggs of T. leonina against different heterologous Ag, no cross-reactions against T. canis ES and A. suum ES Ag were observed using a single dose. Similarly, in multiple doses no response against T. canis ES Ag was observed. In mice inoculated with adult worms extract of T. leonina cross-reactions with T. canis ES and A. suum ES Ag did not occur. Sera from BALB c mice infected with Embryonated eggs of A. suum, was tested using ES Ag from both A. suum and T. canis and no reactions were observed. This fact confirmed the resistance of this murine strain to A. suum Embryonated eggs. When we used sera of susceptible C57BL 10 mice infected against different heterologous Ag, we observed no cross-reactions against T. canis ES Ag. In the case of both BALB c and C57BL 10 mice immunized with a single dose of A. suum adult crude extract no cross-reactions were seen against ES T. canis Ag and with sera from C57BL 10 mice against ES T. leonina. These facts confirmed the specificity of the ES T. canis Ag.
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Cross-reactions of sera from Toxocara canis-infected mice with Toxascaris leonina and Ascaris suum antigens.
International journal for parasitology, 1992Co-Authors: Carmen Cuéllar, S. Fenoy, J.l. GuillénAbstract:Abstract The ELISA method using larval excretory-secretory (E/S) products and homogenized Toxocara canis, Toxascaris leonina and Ascaris suum adult worm extract were used to determine possible crossreactions in BALB/c and C57BL/10 mice, inoculated with Embryonated eggs or adult worm extract of T. canis in single and multiple doses. When we used sera of mice infected with Embryonated eggs of T. canis against different heterologous antigens, we observed no cross-reactions in BALB/c mice against A. suum E/S and adult worm extract antigens with a single dose. In multiple doses this was absent too against T. leonina adult worm extract in BALB/c mice, and in both strains against A. suum E/S and adult worm extract. In BALB/c mice inoculated with adult worm extract of T. canis we did not observe cross-reactions with A. suum E/S antigen with both inoculation doses. In the remainder of the experiments, we observed cross-reactions of different intensities.
Hong Jin - One of the best experts on this subject based on the ideXlab platform.
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single amino acid substitutions in the hemagglutinin of influenza a singapore 21 04 h3n2 increase virus growth in Embryonated chicken eggs
Vaccine, 2006Co-Authors: Helen Zhou, George Kemble, Winnie Chan, Hong JinAbstract:Most of the recently circulating H3N2 influenza A strains do not replicate well in Embryonated chicken eggs and had to be isolated by cell culture, which presents a great challenge for influenza vaccine production using Embryonated chicken eggs. We previously reported that a human H3N2 virus, A/Fujian/411/02, which replicates poorly in eggs, could be improved by changing a minimum of two HA residues (G186V/V226I or H183L/V226A). Here, we extended our work to the A/Singapore/21/04 strain that was also unable to grow in eggs. We showed that a single amino acid substitution of either G186V or A196T in the HA resulted in significantly increased virus replication in eggs without affecting virus antigenicity.
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improvement of influenza a fujian 411 02 h3n2 virus growth in Embryonated chicken eggs by balancing the hemagglutinin and neuraminidase activities using reverse genetics
Journal of Virology, 2005Co-Authors: Helen Zhou, George Kemble, Hong JinAbstract:The H3N2 influenza A/Fujian/411/02-like virus strains that circulated during the 2003-2004 influenza season caused influenza epidemics. Most of the A/Fujian/411/02 virus lineages did not replicate well in Embryonated chicken eggs and had to be isolated originally by cell culture. The molecular basis for the poor replication of A/Fujian/411/02 virus was examined in this study by the reverse genetics technology. Two antigenically related strains that replicated well in Embryonated chicken eggs, A/Sendai-H/F4962/02 and A/Wyoming/03/03, were compared with the prototype A/Fujian/411/02 virus. A/Sendai differed from A/Fujian by three amino acids in the neuraminidase (NA), whereas A/Wyoming differed from A/Fujian by five amino acids in the hemagglutinin (HA). The HA and NA segments of these three viruses were reassorted with cold-adapted A/Ann Arbor/6/60, the master donor virus for the live attenuated type A influenza vaccines (FluMist). The HA and NA residues differed between these three H3N2 viruses evaluated for their impact on virus replication in MDCK cells and in Embryonated chicken eggs. It was determined that replication of A/Fujian/411/02 in eggs could be improved by either changing minimum of two HA residues (G186V and V226I) to increase the HA receptor-binding ability or by changing a minimum of two NA residues (E119Q and Q136K) to lower the NA enzymatic activity. Alternatively, recombinant A/Fujian/411/02 virus could be adapted to grow in eggs by two amino acid substitutions in the HA molecule (H183L and V226A), which also resulted in the increased HA receptor-binding activity. Thus, the balance between the HA and NA activities is critical for influenza virus replication in a different host system. The HA or NA changes that increased A/Fujian/411/02 virus replication in Embryonated chicken eggs were found to have no significant impact on antigenicity of these recombinant viruses. This study demonstrated that the reverse genetics technology could be used to improve the manufacture of the influenza vaccines.