...produce substances toxic to themselves? What are toxin-antitoxin systems? These toxic substances are part...applications. The discovery of toxin-antitoxin systems Toxin-antitoxin systems were first discovered in...division”). The encoded toxin-antitoxin system consists of CcdB (toxin) and CcdA (antitoxin) where CcdB inferes...protein-based toxin-antitoxin systems. One of the most well known protein-based toxin-antitoxin system is ...part of toxin-antitoxin systems that are widely present in bacteria. They consist of a toxin which can...and an antitoxin that suppresses the toxin’s activity. The key to these systems is that the toxin is stable..., it will still inherit some toxin and antitoxin. However, the antitoxin will be degraded leaving the ...

...of Type VI secreted effector toxins, toxin-antitoxin type toxins, and phage holins. They hypothesized that...Bacterial toxins for counter-selection In 2015, the Chen lab harnessed a group of bacterial toxins to facilitate...eight bacterial toxin genes isolated from E. coli or Psuedomonas aeruginosa. These toxins were a mix of ...Tight control of toxin expression is absolutely necessary, because leaky expression of toxin could select ...cassette with one of three toxins from the Khetrapal paper. We selected the three toxins so that at least one...product is a sucrase that converts sucrose into a toxic metabolite. Cells that have undergone a double crossover... that genes that had evolved specifically for toxicity would allow stronger counter-selection than one...

...potent toxin... The ccdB gene, located on the F sex factor plasmid of E. coli, is part of a toxin-antitoxin...operon, codes for the antitoxin protein (CcdA) that protects the cell against the toxic CcdB. Cells that lose...maintenance during cell division. ccdB codes for the toxic protein (CcdB) that acts as a DNA gyrase poison,...through the loss of the F plasmid, succumb to the toxicity of CcdB.   Figure 1: Image from Bernard...because CcdA wasn’t available to counteract the toxin. If, however, an investigator were to successfully... of E. coli that tolerate the expression of the toxin gene. One such strain is DB3.1, which contains a...of DNA gyrase (gyrA462) that is resistant to the toxic effects of CcdB. Another commercially available,...

...guides were considered toxic if they were depleted from the screen. This toxicity was used a proxy for ...safe-targeting guides are more toxic than non-targeting guides. Toxicity is likely due to DNA damage and...the toxicity of guides that have 1-bp mismatch off-target sites, short guides had reduced toxicity compared...affected by low on-target efficacy, non-specific toxicity, and off-target effects. The flaws of RNAi screens... was validated via a growth screen and a ricin toxicity screen since essential and non-essential genes...identified  60% of the essential genes. The ricin toxicity screen had a 10% false discovery rate and identified...identified 67% of previously identified ricin toxicity genes. The screen also discovered several genes previously...

...backbone. Vectors pTOX4, pTOX5, and pTOX6 express the YhaV, MqsR, and Tse2 toxins, respectively, and ...chromoprotein. Vectors pTOX7, pTOX8, and pTOX9 express the YhaV, MqsR, and Tse2 toxins, respectively, and ...Chromoproteins for allelic exchange Figure 3: pTOX plasmids expressing amilCP and tsPurple genes. Image...markers for allelic exchange. These vectors contain a toxin gene (regulated by a rhamnose-inducible promoter...(amilCP) or purple (tsPurple) color. Though the toxin is integrated in the genome, it is not expressed...rhamnose is added which induces expression of the toxin. Any cells that grow after this point will be those...

... bacterial endotoxin is ensured to be less than five endotoxin units per mL. The endotoxin levels are ...recombination rates in FLEX/DIO/fDIO constructs. Endotoxin Endotoxin contamination in vector preparations can ...large animal studies. Endotoxin contamination is minimized by using an endotoxin-free plasmid purification...are determined using a chromogenic endotoxin detection assay based on the amebocyte lysate method. Purity...addition, plasmids are typically prepared using endotoxin-free plasmid purification kits.     Figure...

...alleviates its toxic effect. Negative selection is sometimes called counterselection.  Toxin-antitoxin systems... the loss of a gene product - usually something toxic. This gene is found on the original plasmid and ...systems One negative selection strategy uses the toxin CcdB. Gateway cloning takes advantage of this property...-selection SacB counter-selection relies on the toxic product produced by the SacB gene. sacB comes from...enzyme levansucrase that converts sucrose into a toxic metabolite in gram-negative bacteria. Plating on... cloning purposes (antibiotic resistance genes, toxin genes, and the sacB gene). By tapping into nature...

...growth. Additionally, some protein products may be toxic to the host when expressed, particularly those that... mB-) gal dcm (DE3) pLysS (CamR) Expression of toxic proteins BL21 (DE3) pLysE* Chloramphenicol (pLysE... mB-) gal dcm (DE3) pLysE (CamR) Expression of toxic proteins BL21 star (DE3)   Lacks functional RNaseE... (DE3) General expression; not recommended for toxic proteins BL21-A1 Tetracycline Arabinose-inducible...hsdSB (rB- mB-) gal dcm lacY1 (DE3) Expression of toxic or insoluble proteins Origami2 (DE3)** Streptomycin...λ DE3) [dcm] ∆hsdS/ pLemo (CamR) Expression of toxic, insoluble, or membrane proteins  T7 Express   ...Φ80ΔlacM15, thi, lac-, mtl-, recA+, KmR Expression of toxic proteins  * Denotes the presence of an additional...

...expression of Cre from the standard UAS/GAL4 system is toxic to proliferating cells. A Cre-estrogen receptor ... ligand binding domain-fusion can prevent this toxicity, but with the caveat of partial rather than complete...specificity with low cross-reactivity, as well as low toxicity. FLP/FRT recombinases (from Saccharomyces cerevisiae.... Finally, Rubin’s group assayed the potential toxicity of these recombinases by crossing flies homozygous... recombinases were inherited normally and thus nontoxic. In contrast, 0/79 offspring carried both Cre ...Cre and GAL4, further emphasizing the toxicity of this enzyme in Drosophila. If you're still reading this....161269798. PubMed. Reduction of Cre recombinase toxicity in proliferating Drosophila cells by estrogen-...

...Antibody dependent cellular cytotoxicity (ADCC) Antibody dependent cellular cytotoxicity (ADCC) is a slightly...deposition (ADCD) b) antibody-dependent cellular cytotoxicity (ADCC) c) antibody-dependent cellular phagocytosis...expressing Fcγ receptors binds to IgG and release cytotoxins that kill the target cell. If the pathogen is...and eosinophils, where the eosinophils release cytotoxins via degranulation.  Antibody-dependent cellular...JV. Inhibitory Fc receptors modulate in vivo cytotoxicity against tumor targets. Nat Med. 2000 Apr;6(4...

...channels, optogenetic G-protein coupled receptors (OptoXRs), and photoswitches. Light-gated ion channels directly...exposed to light and change the membrane potential. OptoXRs are modified GPCRs. When exposed to light, they...2020), including light-sensitive chimeric GPCRS (OptoXRs) (Tichy et al., 2019), photoswitchable tethered...orthogonal, remotely-tethered ligands (PORTLs). OptoXRs are chimeras of the extracellular domain of endogenous...heterologous expression of engineered receptors. OptoXRs are great for studying the broad effects of activating...pathway is unknown.      Figure 3: Chimeric OptoXR incorporating rhodopsin undergoes a conformational...Controlling secondary pathways with photoswitches OptoXRs are great for activating entire signaling pathways...

... targeting experiments. If Cas7-11 lacked this toxicity, it would represent a major step forward for CRISPR-based...up the potential of further development of low-toxicity RNA editing tools.   Fig. 1 Schematic of...the significantly reduced amount of off-target toxicity compared to other RNA editing methods — streamlining...viability – meaning there was no measurable cell toxicity – using Cas7-11. This included tests done in cell... cell lines known to be more sensitive to toxicity from RNA editing, such as mouse embryonic stem cells...off-target breaks, almost always resolved without any toxic effects to the cell. This means almost no indels...

...  Lowering cytotoxicity. Different envelope proteins have different levels of cytotoxicity and the mechanisms...mechanisms behind the cytotoxicity can vary. For example, the popular VSV-G envelope protein causes cells... form syncytias that cause the cells to die. Cytotoxicity can also be cell type dependent: if a cell has...before reaching the target cells. VSV-G is also toxic at high concentrations as described above and is...connectivity. However, because of rabies virus’s toxicity, it made more sense to pseudotype another virus...

...neuronal connectivity. These methods are less neurotoxic and better compatible with other neuroscience...system where it replicates, spreads, causes neurotoxicity, and is lethal if left untreated (for review...they also have low immunogenicity and cellular toxicity. AAV vectors can be equipped with strong promoters...while also having the added advantage of lower toxicity, higher specificity and reduced technical variability...Wang, Y., and Harvey, B.K. (2008). Tropism and toxicity of adeno-associated viral vector serotypes 1,2,5,6,7,8,9...retrograde transsynaptic transfer of a protein, tetanus toxin, subsequent to its retrograde axonal transport. ...

...enough signal. This workaround risks cellular phototoxicity and eliminates the possibility of long-term ...have the potential to form aggregates and may be toxic to the cell. Here comes the SunTag How does SunTag...bright images of mitochondria without organelle toxicity. First generation (v1) SunTag is expressed at...brightness and signal-to-noise ratio Less chance of phototoxicity Reduced photobleaching Simplified, long-term...

... If a drug is equally toxic to both lines, it probably has either high toxicity or high off target effects... to no toxicity in the knockout line, it is likely a specific drug with low off-target toxicity. This ...

...eliminate the competition via the production of toxins and antibiotics. Fungi such as Penicillium produce...penicillin, and bacteria in turn possess plasmid-borne toxins like colicins and subtilisins to kill other bacteria... carrying genes for the production of bacterial toxins like colicin also often carry the necessary resistance...organisms can’t use. Others develop resistance to toxic substances such as heavy metals or pesticides, enabling...

...which can be toxic in living cells. BioID was derived from biotin ligase and uses far less toxic biotin for...pair of enzymes that overcome both the speed and toxicity limitations of APEX2 and BioID. In the Ting Lab...describe TurboID and miniTurbo, which utilize non-toxic biotin, but label nearly as quickly as APEX2. What...

...important to note that the biotin-phenol reagent can be toxic to living cells thus APEX is not suitable for organoid...APEX2 plasmids! TurboID and minturbo: Rapid and non-toxic proximity labeling  TurboID and miniTurbo were developed...rapidly label proteins, requires H2O2 which can be toxic to living cells. To circumvent these issues, the...biotin labeling in 10 minutes without any issues in toxicity. TurboID’s signal is significantly greater than...

...recognized by effector cells of the immune system - cytotoxic T lymphocytes (CTLs), natural killer (NK) cells...programmed cell death ligand (PD-L1) that inhibits the cytotoxic activity of CTLs and NK cells. These cells would...immunotherapy. Using activated DCs ex vivo to generate cytotoxic effector T cells, and targeting specific DC subsets... targets like CD19 on tumor cells and exhibit cytotoxic activity. CAR-T cells have consistently shown ...