Precision Microbial Nanobiosynthesis: Knowledge …
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Boucher et al. (2017) have described the functionalization of M. magneticum
AMB-1 magnetosome membranes decorated with RGD peptide-MamC fusion
proteins. The RGD-labeled magnetosomes have been used as magnetic resonance
imaging contrast agent for in vivo molecular imaging of glioblastoma in a mouse
model. Recently, Mickoleit et al. (2020) have confirmed in M. gryphiswaldense how
the use of MamA, MamG, and MamF protein as anchor proteins can be useful
for the making of genetically multifunctionalized magnetosomes. This research has
produced a reusable magnetic biocomposite nanomaterial that simultaneously has
displayed the enzymes beta-glucuronidase and glucose oxidase (GOx), a fluorophore
(mEGFP) and a nanobody (red fluorescent binding protein) on the magnetosome
membrane. This study could lay the groundwork for future generation of biohybrid
nanomaterials with a great potential application in biotechnological and biomedical
fields (Mickoleit et al. 2020).
4.2.2 Frustules
In recent years, the genetic and molecular details of diatoms frustule morphogenesis
have been partially elucidated. To date, whole-genome sequencing has been generated for two marine diatom species Thalassiosira pseudonana and Phaeodactylum
tricornutum, enabling their use as model for biotechnological studies in diatoms.
In particular P. tricornutum is probably the best-characterized of all diatoms so
far, with a small-size genome and easy to grow in laboratory (Butler et al. 2020).
However, further studies on diatom genetics will be required for a complete knowledge of frustules biogenesis process (De Tommasi et al. 2017). Recently, genome
editing approaches like Transcription Activator-Like Effector Nucleases (TALEN)
endonucleases and the clustered regulatory interspaced short palindromic repeats
(CRISPR)/Cas9 system are increasingly being used for the production of transgenic
lines in some diatom species, useful in diatom functional genomic studies on frustule morphogenesis as well as for the development of future genome engineering
approaches in diatoms. Both methods use engineered nucleases that catalyze a target
gene-specific double-stranded DNA break, allowing a complete loss of a specific gene
function and the generation of knockout strains. These approaches for gene down
regulation are very promising in diatom research, especially for diploid species like T.
pseudonana and P. tricornutum for which forward genetic methods based on random
insertion and chemical mutagenesis cannot be not used (Kroth et al. 2018).
Antibody-functionalized frustules of T. pseudonana using genetic approaches
have been described in literature. Delalat et al. (2015) have reported a genetically
engineered diatom T. pseudonana with the incorporation of immunoglobulin Gbinding domain of protein G onto the frustules surface. Such antibody-labeled genetically modified diatoms have enabled an in vitro selective cell targeting and selective
killing of neuroblastoma and B-lymphoma cells (Delalat et al. 2015). Ford et al.
(2016) have described a genetically modified T. pseudonana for the expression of
biosilica-targeted fusion proteins comprising (i) a single domain antibody against
the EA1 S-layer protein of Bacillus anthracis Sterne strain and (ii) a single chain
101
Boucher et al. (2017) have described the functionalization of M. magneticum
AMB-1 magnetosome membranes decorated with RGD peptide-MamC fusion
proteins. The RGD-labeled magnetosomes have been used as magnetic resonance
imaging contrast agent for in vivo molecular imaging of glioblastoma in a mouse
model. Recently, Mickoleit et al. (2020) have confirmed in M. gryphiswaldense how
the use of MamA, MamG, and MamF protein as anchor proteins can be useful
for the making of genetically multifunctionalized magnetosomes. This research has
produced a reusable magnetic biocomposite nanomaterial that simultaneously has
displayed the enzymes beta-glucuronidase and glucose oxidase (GOx), a fluorophore
(mEGFP) and a nanobody (red fluorescent binding protein) on the magnetosome
membrane. This study could lay the groundwork for future generation of biohybrid
nanomaterials with a great potential application in biotechnological and biomedical
fields (Mickoleit et al. 2020).
4.2.2 Frustules
In recent years, the genetic and molecular details of diatoms frustule morphogenesis
have been partially elucidated. To date, whole-genome sequencing has been generated for two marine diatom species Thalassiosira pseudonana and Phaeodactylum
tricornutum, enabling their use as model for biotechnological studies in diatoms.
In particular P. tricornutum is probably the best-characterized of all diatoms so
far, with a small-size genome and easy to grow in laboratory (Butler et al. 2020).
However, further studies on diatom genetics will be required for a complete knowledge of frustules biogenesis process (De Tommasi et al. 2017). Recently, genome
editing approaches like Transcription Activator-Like Effector Nucleases (TALEN)
endonucleases and the clustered regulatory interspaced short palindromic repeats
(CRISPR)/Cas9 system are increasingly being used for the production of transgenic
lines in some diatom species, useful in diatom functional genomic studies on frustule morphogenesis as well as for the development of future genome engineering
approaches in diatoms. Both methods use engineered nucleases that catalyze a target
gene-specific double-stranded DNA break, allowing a complete loss of a specific gene
function and the generation of knockout strains. These approaches for gene down
regulation are very promising in diatom research, especially for diploid species like T.
pseudonana and P. tricornutum for which forward genetic methods based on random
insertion and chemical mutagenesis cannot be not used (Kroth et al. 2018).
Antibody-functionalized frustules of T. pseudonana using genetic approaches
have been described in literature. Delalat et al. (2015) have reported a genetically
engineered diatom T. pseudonana with the incorporation of immunoglobulin Gbinding domain of protein G onto the frustules surface. Such antibody-labeled genetically modified diatoms have enabled an in vitro selective cell targeting and selective
killing of neuroblastoma and B-lymphoma cells (Delalat et al. 2015). Ford et al.
(2016) have described a genetically modified T. pseudonana for the expression of
biosilica-targeted fusion proteins comprising (i) a single domain antibody against
the EA1 S-layer protein of Bacillus anthracis Sterne strain and (ii) a single chain