Journal of Microbiology

Journal Article

Cultivation of Diverse Novel Marine Bacteria from Deep Ocean Sediment Using Spent Culture Supernatant of Ca. Bathyarchaeia Enrichment.: Sidra Erum Ishaq, Tariq Ahmad, Lewen Liang, Ruize Xie, Tiantian Yu, Yinzhao Wang, Fengping Wang; J. Microbiol. 2024;62(8):611-625. Published online July 10, 2024; DOI: https://doi.org/10.1007/s12275-024-00145-w

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Abstract: Most microorganisms resist pure cultivation under conventional laboratory conditions. One of the primary issues for this un-culturability is the absence of biologically produced growth-promoting factors in traditionally defined growth media. However, whether cultivating microbes by providing spent culture supernatant of pivotal microbes in the growth medium can be an effective approach to overcome this limitation is still an under-explored area of research. Here, we used the spent culture medium (SCM) method to isolate previously uncultivated marine bacteria and compared the efficiency of this method with the traditional cultivation (TC) method. In the SCM method, Ca. Bathyarchaeia-enriched supernatant (10%) was used along with recalcitrant organic substrates such as lignin, humic acid, and organic carbon mixture. Ca. Bathyarchaeia, a ubiquitous class of archaea, have the capacity to produce metabolites, making their spent culture supernatant a key source to recover new bacterial stains. Both cultivation methods resulted in the recovery of bacterial species from the phyla Pseudomonadota, Bacteroidota, Actinomycetota, and Bacillota. However, our SCM approach also led to the recovery of species from rarely cultivated groups, such as Planctomycetota, Deinococcota, and Balneolota. In terms of the isolation of new taxa, the SCM method resulted in the cultivation of 80 potential new strains, including one at the family, 16 at the genus, and 63 at the species level, with a novelty ratio of ~ 35% (80/219). In contrast, the TC method allowed the isolation of ~ 10% (19/171) novel strains at species level only. These findings suggest that the SCM approach improved the cultivation of novel and diverse bacteria.

In situ Delivery of Therapeutic Proteins by Recombinant Lactococcus lactis: Lothar Steidler , Sabine Neirynck; J. Microbiol. 2003;41(2):63-72.

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Abstract: Chronic inflammatory bowel disease (IBD) such as Crohn’s disease or ulcerative colitis, affects around 2 in every 1000 individuals in western countries and its incidence, particularly amongst children, is increasing. IBD shows extreme morbidity with impact on all aspects of quality of life. If left untreated, IBD can lead to death. Conventional treatment of IBD involves powerful immunosuppressive chemotherapies and surgical intervention. Long-term anti-inflammatory medication is required and so patients are often subject to a spectrum of unpleasant side effects. Interleukin-10 (IL-10) is a cytokine that acts to suppress inflammation. When however administered by injection, the high levels of IL-10 that are distributed throughout the body also lead to side effects. Lactococcus lactis can be genetically engineered to secrete biologically active cytokines. When applied to the mucosa, these L. lactis can actively deliver such cytokines. By use of this principle we developed a new therapeutic approach for IBD. Administration of L. lactis that secretes murine IL-10 cures and prevents IBD in mice. The use of the engineered L. lactis gets around the problem of delivering IL-10, allowing dramatic reduction of the effective dose. A sincere concern exists about the possible dangers of uncontrolled, deliberate release of genetically modified microorganisms, such as could occur following application in healthcare. We engaged in the establishment of adequate means for biological growth control of engineered L. lactis by targeted

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