Unconventional Domain Research Articles

Beyond the Spectrum: Exploring Unconventional Applications of Fourier Transform Infrared (FTIR) Spectroscopy

Fourier Transform Infrared (FTIR) spectroscopy, once primarily associated with structural analysis, has transcended its conventional role to become a versatile analytical powerhouse with applications spanning diverse fields. This review paper navigates the uncharted territories of FTIR's evolution, highlighting its innovative utilization in unconventional domains. Traditional applications of FTIR in structural analysis have expanded into captivating realms such as art conservation, nanotechnology, life sciences, and environmental monitoring. We delve into the transformation of FTIR into a tool for pigment identification in historical artworks, its role in probing nanoscale materials for composition analysis, and its emergence as a vital diagnostic tool in disease detection. Moreover, we explore how FTIR enables real-time air quality assessment, influencing urban environmental management. The synergy of FTIR with other techniques, the advancements in FTIR imaging, and its integration with bioinformatics contribute to the evolving landscape of applications. As FTIR continues to reshape the boundaries of knowledge and innovation, this paper serves as a tribute to its versatility, inspiring researchers to unlock new insights, collaborate across disciplines, and drive the progression of science.

UnityGPT vs. ChatGPT: A Comparative Review for Frontier Scientists

Artificial intelligence tools based on Large Language Models (LLMs), such as OpenAI’s ChatGPT, are revolutionizing how we process and synthesize information. However, these tools can be anemic when applied to niche or unconventional domains, such as parapsychology. This is due to the fact that the input content used to train these LLMs draws predominately from mainstream internet sources (e.g., Wikipedia), and thus, the corresponding outputs inherit various biases surrounding heterodox subjects. This review introduces UnityGPT, a custom AI tool provided with a vast array of unconventional research from a plurality of disciplines, intended for use as a primary research tool in the frontier sciences. The article summarizes the technology approach of both ChatGPT and UnityGPT, and their relative strengths and weaknesses.

Unidirectional domain growth of hexagonal boron nitride thin films

Two-dimensional van der Waals (2D-vdW) layered hexagonal boron nitride (h-BN) has gained tremendous research interest over recent years due to its unconventional domain growth morphology, fascinating properties and application potentials as an excellent dielectric layer for 2D-based nano-electronics. However, the unidirectional domain growth of h-BN thin films directly on insulating substrates remains significantly challenging because of high-bonding anisotropicity and complex growth kinetics than the conventional thin films growth, thus resulting in the formation of randomly oriented domains morphology, and hindering its usefulness in integrated nano-devices. Here, ultra-wide bandgap h-BN thin films are grown directly on low-miscut atomically smooth highly insulating c-plane sapphire substrates (without using any metal catalytic layer) by pulsed laser deposition, showing remarkable unidirectional triangular-shape domains morphology. This unidirectional domain growth is attributed to the step-edge guided nucleation caused by reducing the film-substrate interfacial symmetry and energy, thereby breaking the degeneracy of nucleation sites of random domains, as revealed by the density functional theory (DFT) calculations. Through extensive characterizations, we further demonstrate the excellent single crystal-like functional properties of films. Our findings might pave the way for feasible large-area direct growth of electronic-quality h-BN thin films on insulating substrates for high-performance 2D-electronics, and in addition would be beneficial for hetero engineering of 2D-vdW materials with emergent phenomena.

A genetically linked pair of NLR immune receptors shows contrasting patterns of evolution

Throughout their evolution, plant nucleotide-binding leucine-rich-repeat receptors (NLRs) have acquired widely divergent unconventional integrated domains that enhance their ability to detect pathogen effectors. However, the functional dynamics that drive the evolution of NLRs with integrated domains (NLR-IDs) remain poorly understood. Here, we reconstructed the evolutionary history of an NLR locus prone to unconventional domain integration and experimentally tested hypotheses about the evolution of NLR-IDs. We show that the rice (Oryza sativa) NLR Pias recognizes the effector AVR-Pias of the blast fungal pathogen Magnaporthe oryzae. Pias consists of a functionally specialized NLR pair, the helper Pias-1 and the sensor Pias-2, that is allelic to the previously characterized Pia pair of NLRs: the helper RGA4 and the sensor RGA5. Remarkably, Pias-2 carries a C-terminal DUF761 domain at a similar position to the heavy metal-associated (HMA) domain of RGA5. Phylogenomic analysis showed that Pias-2/RGA5 sensor NLRs have undergone recurrent genomic recombination within the genus Oryza, resulting in up to six sequence-divergent domain integrations. Allelic NLRs with divergent functions have been maintained transspecies in different Oryza lineages to detect sequence-divergent pathogen effectors. By contrast, Pias-1 has retained its NLR helper activity throughout evolution and is capable of functioning together with the divergent sensor-NLR RGA5 to respond to AVR-Pia. These results suggest that opposite selective forces have driven the evolution of paired NLRs: highly dynamic domain integration events maintained by balancing selection for sensor NLRs, in sharp contrast to purifying selection and functional conservation of immune signaling for helper NLRs.

Edge dislocations in multicomponent solid solution alloys: Beyond traditional elastic depinning

High-entropy alloys (HEA) form solid solutions with large chemical disorder and excellent mechanical properties. We investigate the origin of HEA strengthening in face-centered cubic (FCC) single-phase HEAs through molecular dynamics simulations of dislocations, in particular, the equiatomic $\rm CrCoNi$, $\rm CrMnCoNi$, $\rm CrFeCoNi$, $\rm CrMnFeCoNi$, $\rm FeNi$, and also, $\rm Fe_{0.4}Mn_{0.27}Ni_{0.26}Co_{0.05}Cr_{0.02}$, $\rm Fe_{0.7}Ni_{0.11}Cr_{0.19}$. The dislocation correlation length $\xi$, roughness amplitude $R_{a}$, and stacking fault widths $W_{SF}$ are tracked as a function of stress. All alloys are characterized by a well defined depinning stress ($\sigma_c$) and we find a novel regime where exceptional strength is observed, and a fortuitous combination takes place, of small stacking fault widths and large dislocation roughness $R_{a}$. Thus the depinning of two partials seems analogous to unconventional domain wall depinning in disordered magnetic thin films. This novel regime is identified in specific compositions commonly associated with exceptional mechanical properties ($\rm CrCoNi$, $\rm CrMnCoNi$, $\rm CrFeCoNi$, and $\rm CrMnFeCoNi$). Yield stress from analytical solute-strengthening models underestimates largely the results in these cases. A possible strategy for increasing strength in multi-component single-phase alloys is the combined design of stacking fault width and element-based chemical disorder.

From early to present and future achievements of EELS in the TEM

This paper reviews the implementation of Electron Energy Loss Spectroscopy (EELS) in a Transmission Electron Microscope (TEM), as an essential tool for advanced analytical studies, exhibiting a unique level of performance in terms of spatial resolution down to the interatomic distances for imaging and sensitivity down to the single atom for elemental identification. In terms of spectral resolution, it offers access with a resolution as good as a few meV, to a very broad spectral domain extending from tens of meV (in the IR) up to a few keV (in the X-ray). This new generation of instrument (EELS+(S)TEM) is now routinely used to investigate the structural, spectral, electronic and chemical properties of a wide range of materials and to broaden spectacularly the field of novel information which it provides. A first part of the paper describes the major progress in advanced instrumentation brought by the novel pieces of equipment (spectrometers, monochromators, aberration correctors and detectors) together with the newly elaborated tools for the acquisition and processing of huge data collections. The second part is devoted to the description of the information contained in a global EELS spectrum: (i) from the core-loss domain implying excitations from inner-shell atomic electrons and its application in elemental, chemical and electronic mapping; (ii) from the low-energy domain exhibiting individual or collective excitations of the valence and conduction electron gas, with its most recent developments in band gap mapping and nanoplasmonics; (iii) in the ultra-low energy domain, which is now in its infancy, the surface collective electron excitations, molecular bonds and the vibrations of phonons at surfaces and in the bulk of nanostructures. The third part is devoted to the exploration of unconventional domains of applications, which in many cases associate the EELS acquisition with the generation and the capture of other signals in various environments, in situ operation (temperature, pressure...), absorption or generation of photons (cathodoluminescence, X-ray emission), acquisition and handling of multidimension data (space, energy, momentum, time). In conclusion, EELS fifty years after its first recognition as a useful actor in the development and promotion of the analytical microscopy, has nowadays become an essential tool for the acquisition of many physical parameters with ultimate resolution, thus opening new routes in nanophysics to be explored.

A universal pocket in fatty acyl-AMP ligases ensures redirection of fatty acid pool away from coenzyme A-based activation.

Fatty acyl-AMP ligases (FAALs) channelize fatty acids towards biosynthesis of virulent lipids in mycobacteria and other pharmaceutically or ecologically important polyketides and lipopeptides in other microbes. They do so by bypassing the ubiquitous coenzyme A-dependent activation and rely on the acyl carrier protein-tethered 4'-phosphopantetheine (holo-ACP). The molecular basis of how FAALs strictly reject chemically identical and abundant acceptors like coenzyme A (CoA) and accept holo-ACP unlike other members of the ANL superfamily remains elusive. We show that FAALs have plugged the promiscuous canonical CoA-binding pockets and utilize highly selective alternative binding sites. These alternative pockets can distinguish adenosine 3',5'-bisphosphate-containing CoA from holo-ACP and thus FAALs can distinguish between CoA and holo-ACP. These exclusive features helped identify the omnipresence of FAAL-like proteins and their emergence in plants, fungi, and animals with unconventional domain organizations. The universal distribution of FAALs suggests that they are parallelly evolved with FACLs for ensuring a CoA-independent activation and redirection of fatty acids towards lipidic metabolites.

Unconventional domain wall magnetoresistance of patterned Ni/Nb bilayer structures below superconducting transition temperature of Nb

Scattering of spin-up and spin-down electrons while passing through a ferromagnetic domain wall (DW) leads to an additional resistance for transport current, usually observed prominently in constricted magnetic structures. In this report we use the resistance of the DW as a probe to find an indirect signatures of the theoretically predicted spin-singlet supercurrent to spin-triplet supercurrent conversion effect of ferromagnetic DWs. Here we examine the DW induced resistance in Ni stripe in a bilayer Ni/Nb geometry in the normal state and in the superconducting state of Nb. By making a 3 μm wide gap in the top Nb layer we routed the transport current through the Ni layer in the normal state and in the superconducting state of Nb. In the normal state of Nb, in-field transport measurements showed a clear domain wall magneto-resistance (DWMR) peak of amplitude ∼5.9 mΩ near the coercive field, where the DW density is expected to be maximum. Interestingly, however, below the superconducting transition temperature of Nb, the DWMR peak of the Ni layer showed a sharp drop in the field range where the number of DWs become maximum. This observation may be a possible signature of magnetic DW induced spin-triplet correlations in the Ni layer due to the direct injection of spin-singlet Cooper pairs from Nb into the magnetic DWs.

Large electromechanical strain and unconventional domain switching near phase convergence in a Pb-free ferroelectric

In many ferroelectrics, large electromechanical strains are observed near regions of composition- or temperature- driven phase coexistence. Phenomenologically, this is attributed to easy re-orientation of the polarization vector and/or phase transition, although their effects are highly convoluted and difficult to distinguish experimentally. Here, we used synchrotron X-ray scattering and digital image correlation to differentiate between the microscopic mechanisms leading to large electrostrains in an exemplary Pb-free piezoceramic Sn-doped barium calcium zirconate titanate. Large electrostrains of ~0.2% measured at room-temperature are attributed to an unconventional effect, wherein polarization switching is aided by a reversible phase transition near the tetragonal-orthorhombic phase boundary. Additionally, electrostrains of ~0.1% or more could be maintained from room temperature to 140 °C due to a succession of different microscopic mechanisms. In situ X-ray diffraction elucidates that while 90° domain reorientation is pertinent below the Curie temperature (TC), isotropic distortion of polar clusters is the dominant mechanism above TC.

New Applications in Gas Geochemistry

Gases present in the Earth crust are important in various branches of human activities. Hydrocarbons are a significant energy resource, helium is applied in many high-tech instruments, and studies of crustal gas dynamics provide insight in the geodynamic processes and help monitor seismic and volcanic hazards. Quantitative analysis of methane and CO2 migration is important for climate change studies. Some of them are toxic (H2S, CO2, CO); radon is responsible for the major part of human radiation dose. The development of analytical techniques in gas geochemistry creates opportunities of applying this science in numerous fields. Noble gases, hydrocarbons, CO2, N2, H2, CO, and Hg vapor are measured by advanced methods in various environments and matrices including fluid inclusions. Following the “Geochemical Applications of Noble Gases”(2009), “Frontiers in Gas Geochemistry” (2013), and “Progress in the Application of Gas Geochemistry to Geothermal, Tectonic and Magmatic Studies” (2017) published as special issues of Chemical Geology and “Gas geochemistry: From conventional to unconventional domains” (2018) published as a special issue of Marine and Petroleum Geology, this volume continues the tradition of publishing papers reflecting the diversity in scope and application of gas geochemistry.

Observation of Uncompensated Bound Charges at Improper Ferroelectric Domain Walls.

Low-temperature electrostatic force microscopy (EFM) is used to probe unconventional domain walls in the improper ferroelectric semiconductor Er0.99Ca0.01MnO3 down to cryogenic temperatures. The low-temperature EFM maps reveal pronounced electric far fields generated by partially uncompensated domain-wall bound charges. Positively and negatively charged walls display qualitatively different fields as a function of temperature, which we explain based on different screening mechanisms and the corresponding relaxation time of the mobile carriers. Our results demonstrate domain walls in improper ferroelectrics as a unique example of natural interfaces that are stable against the emergence of electrically uncompensated bound charges. The outstanding robustness of improper ferroelectric domain walls in conjunction with their electronic versatility brings us an important step closer to the development of durable and ultrasmall electronic components for next-generation nanotechnology.

Lorentz TEM study of the magnetic microstructure in near-eutectoid Co-Pt alloys

Abstract In this paper, we report Lorentz Transmission Electron Microscopy (LTEM) observations of magnetic domain structures in a near-eutectoid Co 40 Pt 60 alloy. The crystallographic microstructure is characterized using conventional bright field/dark field TEM imaging. The magnetic induction orientation inside magnetic domains is extracted from Fresnel through-focus images by reconstructing the phase of electron wave using the transport-of-intensity equation. The alloy shows a nano-chessboard pattern composed of the L10 tetragonal and L12 cubic phases. The magnetization distribution in four neighboring L10 tiles in the nano-chessboard structure is found to follow a vortex/anti-vortex configuration to reduce the magnetostatic and magneto-crystalline anisotropy energies. An unconventional domain wall referred to as an inter phase magnetic domain wall (IPMDW) is observed at the inter-phase boundaries of L10 and L12 phases. Magnetic domain walls in other microstructures (tweed microstructure, macro-twinned structure, coarsened L10 plates) are also documented.

Syndapin constricts microvillar necks to form a united rhabdomere in Drosophila photoreceptors.

Drosophila photoreceptors develop from polarized epithelial cells that have apical and basolateral membranes. During morphogenesis, the apical membranes subdivide into a united bundle of photosensory microvilli (rhabdomeres) and a surrounding supporting membrane (stalk). By EMS-induced mutagenesis screening, we found that the F-Bin/Amphiphysin/Rvs (F-BAR) protein syndapin is essential for apical membrane segregation. The analysis of the super-resolution microscopy, STORM and the electron microscopy suggest that syndapin localizes to the neck of the microvilli at the base of the rhabdomere. Syndapin and moesin are required to constrict the neck of the microvilli to organize the membrane architecture at the base of the rhabdomere, to exclude the stalk membrane. Simultaneous loss of syndapin along with the microvilli adhesion molecule chaoptin significantly enhanced the disruption of stalk-rhabdomere segregation. However, loss of the factors involving endocytosis do not interfere. These results indicated syndapin is most likely functioning through its membrane curvature properties, and not through endocytic processes for stalk-rhabdomere segregation. Elucidation of the mechanism of this unconventional domain formation will provide novel insights into the field of cell biology.

Front and Back Covers, Volume 34, Number 1. February 2018

Cover caption, volume 34 issue 1Front CoverAnthropologists have long ignored or criticized mainstream popular culture, so we have not always realized that something as seemingly mundane as a Hollywood film could contain valuable insights for teaching and thinking about the issues that matter to an anthropological perspective on the contemporary world. Given science fiction's intersections with anthropology in using other ‘worlds’ to gain perspective on our own, science fiction films could be particularly good resources for engaging wider audiences with anthropological insights. While there have been occasional examples of such cross‐fertilizations, such as the writings of Ursula Le Guin, the potential of science fiction as a source for anthropological thinking has been by and large neglected. In this issue, David Sutton shows how the recent film Arrival provides one striking example of the overlap between science fiction, anthropology and popular culture. Films such as this, offer much food for thought and for engagement with anthropological understandings of topics ranging from linguistic relativity to culturally constructed temporalities. At a time when anthropology itself has gained increased visibility in popular culture, it behoves us to think through, rather than reject out of hand, the ways that we might highlight these increased opportunities to promote anthropological understandings.Back Cover: ‘WE ARE ALL POLICE’A scene from the taxi station at Ataturk Airport, Istanbul, December 2016, after several deadly attacks against police and military members. Turkish flag stickers read as: ‘We are all police; we are all soldiers’.Scholars across disciplines have recently expanded state‐centred understandings of security (i.e. national security) by looking at the human and non‐human elements of security, including everything from food and ecological systems, to political economy, poverty and even everyday life itself. What kind of critical tools do we need to develop in order to understand our increasingly ‘securitized’ world infused with a growing (and increasingly repurposed) police force that includes both human and non‐human agents of policing?In this issue, Hayal Akarsu focuses on the technicalization of police violence through reform and the expansion of police power into unconventional domains. She shows how the very practice of reforming expands the contours of not only policing practice but also the boundaries of police violence – ostensibly what such reforms are supposed to restrain.While her research remains contextualized within the specific histories of the Turkish police, it has relevance beyond Turkey, as many practices once considered as ‘harsh policing’ have increasingly enjoyed the support of the public in different parts of the world. In such a milieu, an ethnographically nuanced analysis can provide us with a more subtly attuned vantage point, enabling us to understand how technologies of security and policing with seemingly liberal genealogies like community policing or broad democratic police reform can coexist or be aligned with ‘non‐liberal’ and even authoritarian modalities of government.

Biochemical and biophysical properties of a metagenome-derived GH5 endoglucanase displaying an unconventional domain architecture

Endoglucanases are key enzymes in the degradation of cellulose, the most abundant polymer on Earth. The aim of this work was to perform the biochemical and biophysical characterization of CelE2, a soil metagenome derived endoglucanase. CelE2 harbors a conserved domain from glycoside hydrolase family 5 (GH5) and a C-terminal domain with identity to Calx-beta domains. The recombinant CelE2 displayed preference for hydrolysis of oat beta-glucan, followed by lichenan and carboxymethyl cellulose. Optimum values of enzymatic activity were observed at 45°C and pH 5.3, and CelE2 exhibited considerable thermal stability at 40°C for up to 360min. Regarding the cleavage pattern on polysaccharides, the release of oligosaccharides with a wide degree of polymerization indicated a characteristic of endoglucanase activity. Furthermore, the analysis of products generated from the cleavage of cellooligosaccharides suggested that CelE2 exhibited transglycosylation activity. Interestingly, the presence of CaCl2 positively affect CelE2, including in the presence of surfactants. SAXS experiments provided key information on the effect of CaCl2 on the stability of CelE2 and dummy atom and rigid-body models were generated. To the best of our knowledge this is the first biochemical and biophysical characterization of an endoglucanase from family GH5 displaying this unconventional modular organization.

Conjectures for framing cyberwarfare

Cyberspace has emerged as a potentially new (and unconventional) domain for warfare. Much debate has focused on understanding cyber conflict. The ability to critically analyse this phenomenon is important; however, the nascent nature of cyberwarfare and the complexity of the systems involved create challenges not met by conventional approaches. As a first step, this requires an analytical construct to frame discussions in a way that highlights distinct characteristics of the cyber domain. An approach proposed is one of the postulating conjectures for debate as a way to achieve this and to demonstrate its use, both at the strategic and operational levels. It is suggested that such an approach provides one component of a mature analytical framework for the analysis of cyber across a range of warfare domains.

Atomic Scale Structure Changes Induced by Charged Domain Walls in Ferroelectric Materials

Charged domain walls (CDWs) are of significant scientific and technological importance as they have been shown to play a critical role in controlling the switching mechanism and electric, photoelectric, and piezoelectric properties of ferroelectric materials. The atomic scale structure and properties of CDWs, which are critical for understanding the emergent properties, have, however, been rarely explored. In this work, using a spherical-aberration-corrected transmission electron microscope with subangstrom resolution, we have found that the polarization bound charge of the CDW in rhombohedral-like BiFeO3 thin films not only induces the formation of a tetragonal-like crystal structure at the CDW but also stabilizes unexpected nanosized domains with new polarization states and unconventional domain walls. These findings provide new insights on the effects of bound charge on ferroelectric domain structures and are critical for understanding the electrical switching in ferroelectric thin films as well as in memory devices.

Hydraulic fracturing in unconventional gas reservoirs: risks in the geological system part 1

Hydraulic fracturing of unconventional gas reservoirs rapidly developed especially in the USA to an industrial scale during the last decade. Potential adverse effects such as the deterioration of the quality of exploitable groundwater resources, areal footprints, or even the climate impact were not assessed. Because hydraulic fracturing has already been practised for a long time also in conventional reservoirs, the expansion into the unconventional domain was considered to be just a minor but not a technological step, with potential environmental risks. Thus, safety and environmental protection regulations were not critically developed or refined. Consequently, virtually no baseline conditions were documented before on-site applications as proof of evidence for the net effect of environmental impacts. Not only growing concerns in the general public, but also in the administrations in Germany promoted the commissioning of several expert opinions, evaluating safety, potential risks, and footprints of the technology in focus. The first two publications of the workgroup “Risks in the Geological System” of the independent “Information and Dialogue process on hydraulic fracturing” (commissioned by ExxonMobil Production Deutschland GmbH) comprises the strategy and approaches to identify and assess the potential risks of groundwater contamination of the exploitable groundwater system in the context of hydraulic fracturing operations in the Munsterland cretaceous basin and the Lower Saxony Basin, Germany. While being specific with respect to local geology and the estimation of effective hydraulic parameters, generalized concepts for the contamination risk assessment were developed. The work focuses on barrier effectiveness of different units of the overburden with respect to the migration of fracking fluids and methane, and considers fault zones as potential fluid pathway structures.

The degradation of kinesin-like calmodulin binding protein of D. salina (DsKCBP) is mediated by the ubiquitin–proteasome system

Kinesin-like calmodulin binding protein (KCBP) is a member of kinesin-14 subfamily with unconventional domains distinct from other kinesins. This unique kinesin has the myosin tail homology 4 domain (MyTH4) and band4.1, ezrin, radixin and moesin domain (FERM) at the N-terminal which interact with several cytoskeleton proteins. Although KCBP is implicated in several microtubule-related cellular processes, studies on the KCBP of Dunaliella salina (DsKCBP) have not been reported. In this study, the roles of DsKCBP in flagella and cytoskeleton were investigated and the results showed that DsKCBP was present in flagella and upregulated during flagellar assembly indicting that it may be a flagellar kinesin and plays a role in flagellar assembly. A MyTH4-FERM domain of the DsKCBP was identified as a microtubule and actin interacting site. The interaction of DsKCBP with both microtubules and actin microfilaments suggests that this kinesin may be employed to coordinate these two cytoskeleton elements in algal cells. To gain more insights into the cellular function of the kinesin, DsKCBP-interacting proteins were examined using yeast two-hybrid screen. A 26S proteasome subunit Rpn8 was identified as a novel interacting partner of DsKCBP and the MyTH4-FERM domain was necessary for the interaction of DsKCBP with Rpn8. Furthermore, the DsKCBP was polyubiquitinated and up-regulated by proteasome inhibitor and degraded by ubiquitin-proteasome system indicating that proteasome is related to kinesin degradation.

Four signalling domains in the hybrid histidine protein kinase RodK of Myxococcus xanthus are required for activity

In prokaryotes, the principal signal transduction systems operating at the level of protein phosphorylation are the two-component systems. A number of hybrid histidine protein kinases in these systems contain several receiver domains, however, the function of these receiver domains is unknown. The RodK kinase in Myxococcus xanthus has an unconventional domain composition with a putative N-terminal sensor domain followed by a histidine kinase domain and three receiver domains. RodK is essential for the spatial coupling of the two morphogenetic events underlying fruiting body formation in M. xanthus, aggregation of cells into nascent fruiting bodies and the subsequent sporulation of these cells. RodK kinase activity is indispensable for RodK activity. By systematically substituting the conserved, phosphorylatable aspartate residues in the three receiver domains, genetic evidence is provided that each receiver domain is important for RodK function and that each receiver domain has a distinct function, which depends on phosphorylation. Biochemical analyses provided indirect evidence for phosphotransfer from the RodK kinase domain to the third receiver domain. This is the first example of a hybrid histidine protein kinase in which four signalling domains have been shown to be required for full activity.