Human blood lymphocytes were fractionated on glass bead columns charged with sheep erythrocyte (Es) membranes-bearing human C3b (7,000-10,000 molecules/Es). In the passaged cells the proportion of C receptor lymphocytes was strongly reduced, in parallel with the capacity to lyse chicken erythrocytes (Ec) in the presence of IgG-rabbit anti-Ec antibody. In other experiments, lymphocytes forming r...

EcoRII restriction endonuclease is specific for the 5'-CCWGG sequence (W stands for A or T); however, it shows no activity on a single recognition site. To activate cleavage it requires binding of an additional target site as an allosteric effector. EcoRII dimer consists of three structural units: a central catalytic core, made from two copies of the C-terminal domain (EcoRII-C), and two N-term...

In tool use, the intended external goals have to be transformed into bodily movements by taking into account the target-to-movement mapping implemented by the tool. In bimanual tool use, this mapping may depend on the part of the tool that is operated and the effector used (e.g. the left and right hand at the handle bar moving in opposite directions in order to generate the same bicycle movemen...

Incorporation of disulfide bonds into proteins can be critical for function or stability. In bacterial cells, the periplasmic enzyme DsbA is responsible for disulfide incorporation into many extra-cytoplasmic proteins. The type VI secretion system (T6SS) is a widely occurring nanomachine that delivers toxic effector proteins directly into rival bacterial cells, playing a key role in inter-bacte...

Microbial pathogens infect host cells by delivering virulence factors (effectors) that interfere with defenses. In plants, intracellular nucleotide-binding/leucine-rich repeat receptors (NLRs) detect specific effector interference and trigger immunity by an unknown mechanism. The Arabidopsis-interacting NLR pair, RRS1-R with RPS4, confers resistance to different pathogens, including Ralstonia s...

Most type VI secretion systems (T6SSs) described to date are protein delivery apparatuses that mediate bactericidal activities. Several T6SSs were also reported to mediate virulence activities, although only few anti-eukaryotic effectors have been described. Here, we identify three T6SSs in the marine bacterium Vibrio proteolyticus and show that T6SS1 mediates bactericidal activities under warm...

Type III pili deliver effector proteins (virulence factors) from bacterial pathogens to host cells. Plants express disease resistance (R) proteins that respond specifically to a particular type III effector by activating immune responses. We demonstrated previously that two unrelated type III effectors from Pseudomonas syringae target and modify the Arabidopsis RIN4 protein. Here, we show that ...

The oomycetes form a phylogenetically distinct group of eukaryotic microorganisms that includes some of the most notorious pathogens of plants. Oomycetes accomplish parasitic colonization of plants by modulating host cell defenses through an array of disease effector proteins. The biology of effectors is poorly understood but tremendous progress has been made in recent years. This review classi...

Spleen cells sensitized against trinitrophenyl (TNP)-modified stimulator cells displayed a cytotoxic effect against syngeneic TNP-modified but not dinitrophenyl (DNP)-modified target cells. The same finding was observed in the opposite direction; that is, effector cells sensitized against DNP-modified stimulator cells did not cross kill TNP-modified targets. The specificity of the anti-TNP effe...

TAL effectors are re-targetable transcription factors used for tailored gene regulation and, as TAL effector-nuclease fusions (TALENs), for genome engineering. Their hallmark feature is a customizable central string of polymorphic amino acid repeats that interact one-to-one with individual DNA bases to specify the target. Sequences targeted by TAL effector repeats in nature are nearly all direc...