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Microbiological Considerations in the Selection and Validation of Filter Sterilization
Published in Maik W. Jornitz, Filtration and Purification in the Biopharmaceutical Industry, 2019
For example, organisms of the family Rickettsiaceae number among them numerous important human pathogens (a pathogen being defined as an organism known to produce disease). Among the diseases produced by members of this family are typhus, Rocky Mountain spotted fever, trench fever, and psittacosis (Coxiella burnetti). Fortunately, the majority of organisms in this family would not be expected to survive in dry powder active ingredients or excipients, nor in the typical compounding environment. However, some Coxiella spp. can survive heat and drying and all of these organisms can survive at −70°C for extended periods of time and in lyophilized materials. These organisms lack rigid cell walls and as a result are pleomorphic, which means they are variable in size and shape. These organisms can be found in nature in the 0.3- to 0.6-mm size range which is to say that they could be at least as difficult to filter as B. diminuta.
Recent advances of algae-bacteria consortia in aquatic remediation
Published in Critical Reviews in Environmental Science and Technology, 2023
Sheng-Nan Li, Chaofan Zhang, Fanghua Li, Nan-Qi Ren, Shih-Hsin Ho
Endosymbiosis in the form of endocytobiosis, is an intimate form of symbiosis, in which the endosymbiont exists intracellularly within the host symbiotic partner (Woyke & Schulz, 2019). To date, several intracellular bacteria have been identified within cells from a number of algal classes, including Euglenophyceae, Chlorophyceae, Chrysophyceae, and Dinophyceae (Wujek, 1979). One of the most prominently endosymbiotic bacteria is the order Rickettsiales, which is currently divided into three families: Rickettsiaceae, Anaplasmataceae, and Candidatus Midichloriaceae (Szokoli et al., 2016). Rickettsiales are obligate intracellular bacteria originally found in metazoans, which have recently been shown to be extensive endosymbionts of various protists. For example, Yurchenko et al. (2018) illustrated that several distantly associated eustigmatophytes (coccoid algae belonging to a class of stramenopile algae (ochrophytes)) could be infected by Candidatus Phycorickettsia gen. nov., a new member of the family Rickettsiaceae (Figure 3e). The recent discovery of eustigmatophytes by Ševčíková et al. (2019), has provided exciting and novel information on endosymbiosis, with eustigmatophytes hosting Candidatus Phycorickettsia as endosymbionts, with an operon of unclear function (ebo) obtained by horizontal genes transfer from the endosymbiont lineage, being found in the plastid genomes of eustigmatophytes.