The Experts below are selected from a list of 873 Experts worldwide ranked by ideXlab platform
Esther Mahabir - One of the best experts on this subject based on the ideXlab platform.
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emergency prevention of extinction of a transgenic allele in a less fertile transgenic Mouse line by crossing with an inbred or Outbred Mouse Strain coupled with assisted reproductive technologies
Reproduction Fertility and Development, 2007Co-Authors: Anna Mayer, D Bulian, Hagen Scherb, Martin Hrabe De Angelis, Jorg Schmidt, Esther MahabirAbstract:Certain transgenic Mouse lines are difficult to breed or archive and, consequently, their transgenes become lost. We examined a C57BL/6 Mouse line (B6-tg), transgenic for green fluorescent protein (GFP) with low fertility, and its crosses with the more prolific inbred C3HeB/FeJ (C3) and Outbred Swiss (SW) Strains in order to assess the possibility of emergency prevention of extinction of a transgenic allele by using assisted reproductive technologies (ART). Out-crossing was performed by natural mating or in vitro fertilisation (IVF) with heterozygous mice. Most of the crossing combinations resulted in improved archiving and rederivation efficiencies of the transgenic allele. Natural crossing increased both mean litter size by two to three pups and the superovulatory rate from 69% for B6-tg to 70-90% for females from the out-crosses. Each plug-positive B6-tg female yielded an average of 4.6 two-cell embryos, whereas females from the out-crosses produced three- to fivefold that amount. After thawing, 13% of B6-tg embryos and 6-12% of out-crossed embryos developed into transgenic pups after transfer into recipients. After IVF with cryopreserved spermatozoa, cleavage rates were 4% for B6-tg, 22-37% for B6-tg oocytes out-crossed with C3 and SW spermatozoa, 9-49% for gametes from out-crossed mice and 28-44% for back-crosses with B6 oocytes. Transgenic pups were not derived from IVF with B6-tg gametes when either fresh or cryopreserved spermatozoa were used. Rederivation efficiencies were 7% and 4% from out-crosses of B6-tg oocytes with C3 and SW spermatozoa, respectively, 6-22% for gametes from out-crossed mice and 4-10% for the back-crosses. Although out-crossing changes the original genetic background, the strategy of crossing coupled with ART prevents the extinction of an allele of interest, especially where archiving and rederivation of the transgenic line fail.
Wendell W Weber - One of the best experts on this subject based on the ideXlab platform.
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tissue and gender specific expression of n acetyltransferase 2 nat2 during development of the Outbred Mouse Strain cd 1
Drug Metabolism and Disposition, 2000Co-Authors: Lourdes Estrada, Kimon C Kanelakis, Gerald N Levy, Wendell W WeberAbstract:The human N-acetyltransferase (Nat2) genetic polymorphisms have been modeled in Mouse Strains. We determined the phenotype and genotype of the N-acetyltransferase 2 (Nat2*) gene among Outbred CD-1 mice and found a mixed population of heterozygous and rapid and slow homozygous genotypes. Phenotypes determined with p-aminobenzoic acid demonstrated complete concordance of slow and rapid genotype and phenotype. The kidney p-aminobenzoic acid/Nat2-acetylating activity of CD-1 female mice showed a 2.5-fold increase at 80 days of age compared with day 1, whereas males showed a 4.3-fold increase at 25 days and a 5.8-fold increase at 80 days. Immunoblot analysis revealed a 2-fold increase in male kidney Nat immunoreactive protein at 80 days of age, whereas no significant differences were detected in female mice. Likewise, the Nat2 mRNA levels determined by ribonuclease protection assay showed an increase in transcript levels in kidney of male mice during postnatal development, whereas they remained unchanged in females. Gender-associated differences of Nat2 activity, protein, and transcript levels were absent in liver. These observations suggest that the increase in Nat2 enzymatic activity in kidney is accomplished by an increase in transcript. We propose that the observed increase in Nat2 transcript expression in male mice may be a result of androgen regulation during development.
Anna Mayer - One of the best experts on this subject based on the ideXlab platform.
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emergency prevention of extinction of a transgenic allele in a less fertile transgenic Mouse line by crossing with an inbred or Outbred Mouse Strain coupled with assisted reproductive technologies
Reproduction Fertility and Development, 2007Co-Authors: Anna Mayer, D Bulian, Hagen Scherb, Martin Hrabe De Angelis, Jorg Schmidt, Esther MahabirAbstract:Certain transgenic Mouse lines are difficult to breed or archive and, consequently, their transgenes become lost. We examined a C57BL/6 Mouse line (B6-tg), transgenic for green fluorescent protein (GFP) with low fertility, and its crosses with the more prolific inbred C3HeB/FeJ (C3) and Outbred Swiss (SW) Strains in order to assess the possibility of emergency prevention of extinction of a transgenic allele by using assisted reproductive technologies (ART). Out-crossing was performed by natural mating or in vitro fertilisation (IVF) with heterozygous mice. Most of the crossing combinations resulted in improved archiving and rederivation efficiencies of the transgenic allele. Natural crossing increased both mean litter size by two to three pups and the superovulatory rate from 69% for B6-tg to 70-90% for females from the out-crosses. Each plug-positive B6-tg female yielded an average of 4.6 two-cell embryos, whereas females from the out-crosses produced three- to fivefold that amount. After thawing, 13% of B6-tg embryos and 6-12% of out-crossed embryos developed into transgenic pups after transfer into recipients. After IVF with cryopreserved spermatozoa, cleavage rates were 4% for B6-tg, 22-37% for B6-tg oocytes out-crossed with C3 and SW spermatozoa, 9-49% for gametes from out-crossed mice and 28-44% for back-crosses with B6 oocytes. Transgenic pups were not derived from IVF with B6-tg gametes when either fresh or cryopreserved spermatozoa were used. Rederivation efficiencies were 7% and 4% from out-crosses of B6-tg oocytes with C3 and SW spermatozoa, respectively, 6-22% for gametes from out-crossed mice and 4-10% for the back-crosses. Although out-crossing changes the original genetic background, the strategy of crossing coupled with ART prevents the extinction of an allele of interest, especially where archiving and rederivation of the transgenic line fail.
Ann E Jerse - One of the best experts on this subject based on the ideXlab platform.
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experimental gonococcal genital tract infection and opacity protein expression in estradiol treated mice
Infection and Immunity, 1999Co-Authors: Ann E JerseAbstract:The development of effective prophylactic agents against gonorrhea and the study of adaptation by Neisseria gonorrhoeae to the urogenital mucosa are hindered by the lack of a well-established animal model of gonococcal genital tract infection. Here, a murine model of long-term gonococcal genital tract infection is described. Female BALB/c mice were treated with 17-beta-estradiol and inoculated intravaginally with wild-type gonococcal Strain FA1090 or MS11. N. gonorrhoeae was recovered from vaginal swabs for an average of 12 to 13 days following inoculation with 10(6) CFU of either Strain. Inflammation occurred in over 80% of infected mice, and diplococci were associated with epithelial cells and neutrophils in stained vaginal smears. Ascended infection occurred in 17 to 20% of mice inoculated with Strain FA1090. An Outbred Mouse Strain (SLC:ddY) previously reported to be naturally susceptible to N. gonorrhoeae was also tested; however, as with BALB/c mice, estradiol was required for prolonged infection. Although piliation was not maintained during experimental murine infection, 46 to 100% of vaginal isolates from four of eight BALB/c mice and three of four SLC:ddY mice expressed one or more opacity (Opa) proteins within 4 days after inoculation with an Opa-negative variant of Strain FA1090. The observed selection for and/or induction of gonococcal Opa protein expression during murine infection appears to parallel events that occur during experimental urethritis in volunteers.
Mihaela Gadjeva - One of the best experts on this subject based on the ideXlab platform.
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frontline science employing enzymatic treatment options for management of ocular biofilm based infections
Journal of Leukocyte Biology, 2019Co-Authors: Abirami Kugadas, Jennifer Geddesmcalister, Antonio Digiandomenico, David B Sykes, Michael K Mansour, Rossen Mirchev, Mihaela GadjevaAbstract:: Pseudomonas aeruginosa-induced corneal keratitis is a sight-threatening disease. The rise of antibiotic resistance among P. aeruginosa keratitis isolates makes treatment of this disease challenging, emphasizing the need for alternative therapeutic modalities. By comparing the responses to P. aeruginosa infection between an Outbred Mouse Strain (Swiss Webster, SW) and a susceptible Mouse Strain (C57BL6/N), we found that the inherent neutrophil-killing abilities of these Strains correlated with their susceptibility to infection. Namely, SW-derived neutrophils were significantly more efficient at killing P. aeruginosa in vitro than C57BL6/N-derived neutrophils. To interrogate whether the distinct neutrophil killing capacities were dependent on endogenous or exogenous factors, neutrophil progenitor cell lines were generated. The in vitro differentiated neutrophils from either SW or C57BL6/N progenitors retained the differential killing abilities, illustrating that endogenous factors conferred resistance. Consistently, quantitative LC-MS/MS analysis revealed Strain-specific and infection-induced alterations of neutrophil proteomes. Among the distinctly elevated proteins in the SW-derived proteomes were α-mannosidases, potentially associated with protection. Inhibition of α-mannosidases reduced neutrophil bactericidal functions in vitro. Conversely, topical application of α-mannosidases reduced bacterial biofilms and burden of infected corneas. Cumulatively, these data suggest novel therapeutic approaches to control bacterial biofilm assembly and improve bacterial clearance via enzymatic treatments.
