To establish a C57BL/6N mouse model infected with Giardia lamblia ( G lamblia ) isolates from human origin Method Two groups of C57BL/6N mouse were inoculated with purified cysts of two G lamblia isola...To establish a C57BL/6N mouse model infected with Giardia lamblia ( G lamblia ) isolates from human origin Method Two groups of C57BL/6N mouse were inoculated with purified cysts of two G lamblia isolates (CD and XZ) by gavage separately Patterns and curves of cyst excretion of the infected mice were observed and summarized Histopathological changes of the small intestines of the infected mice were observed Results Thirty six mice receiving 1×10 4 cysts each were all infected The C57BL/6N mouse showed high susceptibility to G lamblia infection There was no notable distinction between the two groups of the mice infected by the cysts of CD and XZ isolates Cyst excretion occurred with intermittence Of 36 infected mice, 32 (89%) passed cysts intermittently and 4 (11%) others persistently The latent period of cyst excretion was 0-3 days p i (post inoculation) The interruption of cyst excretion ranged from 12 to 20 days p i The fastigium of the cyst excretion was on day 6 p i The peak count of the cysts passed during a 2 h collection period was 2 3×10 7 /g fecal specimen Edema, inflammation, cell infiltration, small blood vessels congestion, mitotic figures and mucosa necrosis appeared in sections of intestines Conclusion C57Bl/6N mouse is a suitable animal model of G lamblia展开更多
The predatory behavior and functional response of all larval stages and adults of Nephaspis oculatus (Blatchley), a predacious coccinellid, on various egg densities of Bemisia argentifolii Bellows & Perrin...The predatory behavior and functional response of all larval stages and adults of Nephaspis oculatus (Blatchley), a predacious coccinellid, on various egg densities of Bemisia argentifolii Bellows & Perring, and prey preference of adult N. oculatus, were studied in the laboratory. Daily consumption of eggs of B. argentifolii by N. oculatus was evaluated at six different densities to obtain functional response curves for all active stages of the coccinellid. Bemisia argentifolii eggs were offered to N. oculatus on collard leaf disks in Petri dish arenas over a 24\|h period at 26 7 2℃ and a photoperiod of 14∶10 (L∶D) h. Linear relationships were observed between percentage prey consumed and prey density, with r 2 values between 0 82-0 99 for all stages except for the fourth instar that had a smaller r 2 value (0 64). Functional response curves of prey consumption by N. oculatus against density of B. argentifolii eggs fitted the type II model of Holling's disc equation for all larval stages and both the male and female adults. Adult females consumed more prey than adult males. The maximum theoretical number of prey consumed per day increased with larval development. The fourth instar was the most effective larval predator, followed by the third instar, the second instar, and finally, the first instar. Based on the functional response parameters, a maximum of 321, 312, 237, 229, 73, and 34 B. argentifolii eggs could be attacked by an adult female, a fourth instar, an adult male, a third instar, a second instar, and a first instar of N. oculatus, respectively. Nephaspis oculatus adults strongly preferred collard to tomato, soybean, eggplant or sweetpotato for oviposition and foraging. Nephaspis oculatus did not deposit any eggs on soybean and tomato.展开更多
Genomic distribution of the nucleosome, the basic unit of chromatin, contains important epigenetic information. To map nucleosome distribution in structurally and functionally differentiated micronucleus(MIC) and macr...Genomic distribution of the nucleosome, the basic unit of chromatin, contains important epigenetic information. To map nucleosome distribution in structurally and functionally differentiated micronucleus(MIC) and macronucleus(MAC) of the ciliate Tetrahymena thermophila, we have purified MIC and MAC and performed micrococcal nuclease(MNase) digestion as well as hydroxyl radical cleavage. Different factors that may affect MNase digestion were examined, to optimize mono-nucleosome production. Mono-nucleosome purity was further improved by ultracentrifugation in a sucrose gradient. As MNase concentration increased, nucleosomal DNA sizes in MIC and MAC converged on 147 bp, as expected for the nucleosome core particle. Both MNase digestion and hydroxyl radical cleavage consistently showed a nucleosome repeat length of^200 bp in MAC of Tetrahymena, supporting ~50 bp of linker DNA. Our work has systematically tested methods currently available for mapping nucleosome distribution in Tetrahymena, and provided a solid foundation for future epigenetic studies in this ciliated model organism.展开更多
基金ThisstudywassupportedpartlybytheNaturalScienceFoundationofBeijing (No 7992 0 0 2 )theNaturalScienceFoundationofHebeiProvince (No 30 0 369)
文摘To establish a C57BL/6N mouse model infected with Giardia lamblia ( G lamblia ) isolates from human origin Method Two groups of C57BL/6N mouse were inoculated with purified cysts of two G lamblia isolates (CD and XZ) by gavage separately Patterns and curves of cyst excretion of the infected mice were observed and summarized Histopathological changes of the small intestines of the infected mice were observed Results Thirty six mice receiving 1×10 4 cysts each were all infected The C57BL/6N mouse showed high susceptibility to G lamblia infection There was no notable distinction between the two groups of the mice infected by the cysts of CD and XZ isolates Cyst excretion occurred with intermittence Of 36 infected mice, 32 (89%) passed cysts intermittently and 4 (11%) others persistently The latent period of cyst excretion was 0-3 days p i (post inoculation) The interruption of cyst excretion ranged from 12 to 20 days p i The fastigium of the cyst excretion was on day 6 p i The peak count of the cysts passed during a 2 h collection period was 2 3×10 7 /g fecal specimen Edema, inflammation, cell infiltration, small blood vessels congestion, mitotic figures and mucosa necrosis appeared in sections of intestines Conclusion C57Bl/6N mouse is a suitable animal model of G lamblia
文摘The predatory behavior and functional response of all larval stages and adults of Nephaspis oculatus (Blatchley), a predacious coccinellid, on various egg densities of Bemisia argentifolii Bellows & Perring, and prey preference of adult N. oculatus, were studied in the laboratory. Daily consumption of eggs of B. argentifolii by N. oculatus was evaluated at six different densities to obtain functional response curves for all active stages of the coccinellid. Bemisia argentifolii eggs were offered to N. oculatus on collard leaf disks in Petri dish arenas over a 24\|h period at 26 7 2℃ and a photoperiod of 14∶10 (L∶D) h. Linear relationships were observed between percentage prey consumed and prey density, with r 2 values between 0 82-0 99 for all stages except for the fourth instar that had a smaller r 2 value (0 64). Functional response curves of prey consumption by N. oculatus against density of B. argentifolii eggs fitted the type II model of Holling's disc equation for all larval stages and both the male and female adults. Adult females consumed more prey than adult males. The maximum theoretical number of prey consumed per day increased with larval development. The fourth instar was the most effective larval predator, followed by the third instar, the second instar, and finally, the first instar. Based on the functional response parameters, a maximum of 321, 312, 237, 229, 73, and 34 B. argentifolii eggs could be attacked by an adult female, a fourth instar, an adult male, a third instar, a second instar, and a first instar of N. oculatus, respectively. Nephaspis oculatus adults strongly preferred collard to tomato, soybean, eggplant or sweetpotato for oviposition and foraging. Nephaspis oculatus did not deposit any eggs on soybean and tomato.
基金supported by the Natural Science Foundation of China(31522051,31470064)the funding awarded to Weibo Song(15-12-1-1-jch)+3 种基金the Qingdao National Laboratory for Marine Science and Technology,ChinaYifan Liu was supported by National Sanitation Foundation(MCB 1411565)National Institute of Health(R01 GM087343)the Department of Pathology at the University of Michigan
文摘Genomic distribution of the nucleosome, the basic unit of chromatin, contains important epigenetic information. To map nucleosome distribution in structurally and functionally differentiated micronucleus(MIC) and macronucleus(MAC) of the ciliate Tetrahymena thermophila, we have purified MIC and MAC and performed micrococcal nuclease(MNase) digestion as well as hydroxyl radical cleavage. Different factors that may affect MNase digestion were examined, to optimize mono-nucleosome production. Mono-nucleosome purity was further improved by ultracentrifugation in a sucrose gradient. As MNase concentration increased, nucleosomal DNA sizes in MIC and MAC converged on 147 bp, as expected for the nucleosome core particle. Both MNase digestion and hydroxyl radical cleavage consistently showed a nucleosome repeat length of^200 bp in MAC of Tetrahymena, supporting ~50 bp of linker DNA. Our work has systematically tested methods currently available for mapping nucleosome distribution in Tetrahymena, and provided a solid foundation for future epigenetic studies in this ciliated model organism.
