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  • 1
    In: Blood, American Society of Hematology, Vol. 104, No. 11 ( 2004-11-16), p. 5192-5192
    Abstract: Human cytomegalovirus (HCMV) remains a cause of serious infectious complications after allogeneic transplantation of hematopoietic stem cells, especially in recipients of T cell depleted grafts. Here, we investigated the incidence of CMV-DNAemia in a cohort of 100 pediatric patients with leukemias and nonmalignant diseases, who received megadoses of CD34+ or CD133+ selected (and therefore highly T-cell depleted) grafts from matched unrelated or mismatched related (haploidentical) donors. Graft versus host disease was minimized with this approach (acute GvHD grade III-IV 5%) but T-cell recovery was delayed in most patients. All patients received prophylactic acyclovir. PCR screening for CMV was performed weekly from leukocytes and plasma and additional antiviral treatment was started in the case of positive findings. Cumulative incidence of CM-DNAemia at day 100 was 29%. Seropositive recipients (n=44) had a significantly higher incidence of CMV-DNAemia than seronegative recipients (n=56) (64% vs. 0.05%; p=0.0001). In contrast, the incidence was not influenced by the serostatus of the donors (patients with seropositve donors (n=41): 33%; patients with seronegative donors (n=59): 28%; p=0.6). D+R+ pairs were not superior to D-R+ pairs. CMV related over-all mortality was & lt;10%. Conclusions: the incidence of CMVDNAemia was remarkably low in our transplanted patients, despite profound T-cell depletion. Donor seropositivity had no influence. An explanation for these observations may be, that only purified stem cells were transplanted (representing less than 1% of the total cell number of an unmanipulated graft) and therefore, patients received a minimal number of potentially CMV infected leukocytes.We suppose, that this effect may counterbalance the transiently impaired T-cell function in our patients and supports the use of CD34+ or CD133 selection in order to prevent GvHD.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2004
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 2
    In: Microbial Cell Factories, Springer Science and Business Media LLC, Vol. 22, No. 1 ( 2023-04-15)
    Abstract: Amino acid production features of Corynebacterium glutamicum were extensively studied in the last two decades. Many metabolic pathways, regulatory and transport principles are known, but purely rational approaches often provide only limited progress in production optimization. We recently generated stable synthetic co-cultures, termed Communities of Niche-optimized Strains (CoNoS), that rely on cross-feeding of amino acids for growth. This setup has the potential to evolve strains with improved production by selection of faster growing communities. Results Here we performed adaptive laboratory evolution (ALE) with a CoNoS to identify mutations that are relevant for amino acid production both in mono- and co-cultures. During ALE with the CoNoS composed of strains auxotrophic for either l -leucine or l -arginine, we obtained a 23% growth rate increase. Via whole-genome sequencing and reverse engineering, we identified several mutations involved in amino acid transport that are beneficial for CoNoS growth. The l -leucine auxotrophic strain carried an expression-promoting mutation in the promoter region of brnQ (cg2537), encoding a branched-chain amino acid transporter in combination with mutations in the genes for the Na + /H + -antiporter Mrp1 (cg0326-cg0321). This suggested an unexpected link of Mrp1 to l -leucine transport. The l -arginine auxotrophic partner evolved expression-promoting mutations near the transcriptional start site of the yet uncharacterized operon argTUV (cg1504-02). By mutation studies and ITC, we characterized ArgTUV as the only l -arginine uptake system of C. glutamicum with an affinity of K D  = 30 nM. Finally, deletion of argTUV in an l -arginine producer strain resulted in a faster and 24% higher l -arginine production in comparison to the parental strain. Conclusion Our work demonstrates the power of the CoNoS-approach for evolution-guided identification of non-obvious production traits, which can also advance amino acid production in monocultures. Further rounds of evolution with import-optimized strains can potentially reveal beneficial mutations also in metabolic pathway enzymes. The approach can easily be extended to all kinds of metabolite cross-feeding pairings of different organisms or different strains of the same organism, thereby enabling the identification of relevant transport systems and other favorable mutations.
    Type of Medium: Online Resource
    ISSN: 1475-2859
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2023
    detail.hit.zdb_id: 2091377-1
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