Fabrication of Electronically Conductive Protein-Heme Nanowires for Power Harvesting.

Electronically conductive protein-based materials can enable the creation of bioelectronic components and devices from sustainable and nontoxic materials, while also being well-suited to interface with biological systems, such as living cells, for biosensor applications. However, as proteins are generally electrical insulators, the ability to render protein assemblies electroactive in a tailorable manner can usher in a plethora of useful materials. Here, an approach to fabricate electronically conductive protein nanowires is presented by aligning heme molecules in proximity along protein filaments, with these nanowires also possessing charge transfer abilities that enable energy harvesting from ambient humidity. The heme-incorporated protein nanowires demonstrate electron transfer over micrometer distances, with conductive atomic force microscopy showing individual nanowires having comparable conductance to other previously characterized heme-based bacterial nanowires. Exposure of multilayer nanowire films to humidity produces an electrical current, presumably through water molecules ionizing carboxyl groups in the filament and creating an unbalanced total charge distribution that is enhanced by the heme. Incorporation of heme and potentially other metal-center porphyrin molecules into protein nanostructures could pave the way for structurally- and electrically-defined protein-based bioelectronic devices.

The Role of Religion and Religiosity in Health-Promoting Care for the Body During the Lockdowns caused by the COVID-19 Pandemic in Egypt, Poland and Romania.

The coronavirus pandemic (COVID-19), as a widespread health threat, has triggered an increase in health-related behaviours, both pro-and anti-health, especially with regard to diet and physical activity. One of the factors modifying the intensity of such activities may be the religious doctrine and religiosity with which a person is associated. A total of 1502 people (1147 women) from countries that feature one dominant religion, took part in the study. Participants represented Sunni Islam (Egypt, n = 798), Roman Catholicism (Poland, n = 443) and Orthodox Christianity (Romania, n = 261). The Coronavirus Anxiety Scale, the Eating Attitudes Test and the Inventory of Physical Activity Objectives were used in the study. Fear of COVID-19 is associated with engagement in pro-health activity, although not to such a significant extent as might be expected. The type of religion in question was revealed to moderate this relationship, but the intensity of religiosity was not found to serve as a moderator.

Communal collective narcissism.

OBJECTIVES: We aimed to introduce, validate, and showcase the utility of a new construct: communal collective narcissism. METHOD: We conducted four studies, in which we developed a new scale for communal collective narcissism (Study 1, N = 856), tested the construct's unique predictions (Study 2, N = 276), examined its social relevance (Study 3, N = 250), and assessed its implications for intergroup outcomes (Study 4, N = 664). RESULTS: In Study 1, we verified the structural soundness of the Communal Collective Narcissism Inventory. In Study 2, we obtained evidence for a defining feature of communal collective narcissism, namely, that it predicts communal, but not agentic, ingroup-enhancement. In Study 3, we illustrated the social relevance of communal collective narcissism. Communal collective narcissists derogated outgroup members, if those outgroups threatened the ingroup and the threat targeted the ingroup's communion. Finally, in Study 4, we showed that communal collective narcissism predicts intergroup outcomes in the communal domain (e.g., humanitarian aid) better than agentic collective narcissism does, whereas agentic collective narcissism predicts intergroup outcomes in the agentic domain (i.e., preferences for military aggression) better than communal collective narcissism does. CONCLUSIONS: The construct of communal collective narcissism is conceptually and empirically distinct from classic (i.e., agentic) collective narcissism.

Country-level correlates of the Dark Triad traits in 49 countries.

OBJECTIVES: The Dark Triad traits (i.e., narcissism, psychopathy, Machiavellianism) capture individual differences in aversive personality to complement work on other taxonomies, such as the Big Five traits. However, the literature on the Dark Triad traits relies mostly on samples from English-speaking (i.e., Westernized) countries. We broadened the scope of this literature by sampling from a wider array of countries. METHOD: We drew on data from 49 countries (N = 11,723; 65.8% female; AgeMean  = 21.53) to examine how an extensive net of country-level variables in economic status (e.g., Human Development Index), social relations (e.g., gender equality), political orientations (e.g., democracy), and cultural values (e.g., embeddedness) relate to country-level rates of the Dark Triad traits, as well as variance in the magnitude of sex differences in them. RESULTS: Narcissism was especially sensitive to country-level variables. Countries with more embedded and hierarchical cultural systems were more narcissistic. Also, sex differences in narcissism were larger in more developed societies: Women were less likely to be narcissistic in developed (vs. less developed) countries. CONCLUSIONS: We discuss the results based on evolutionary and social role models of personality and sex differences. That higher country-level narcissism was more common in less developed countries, whereas sex differences in narcissism were larger in more developed countries, is more consistent with evolutionary than social role models.

Spectral signatures of five hydroxymethyl chlorophyll a derivatives chemically derived from chlorophyll b or chlorophyll f.

Chlorophylls (Chls) are pigments involved in light capture and light reactions in photosynthesis. Chl a, Chl b, Chl d, and Chl f are characterized by unique absorbance maxima in the blue (Soret) and red (Qy) regions with Chl b, Chl d, and Chl f each possessing a single formyl group at a unique position. Relative to Chl a the Qy absorbance maximum of Chl b is blue-shifted while Chl d and Chl f are red-shifted with the shifts attributable to the relative positions of the formyl substitutions. Reduction of a formyl group of Chl b to form 7-hydroxymethyl Chl a, or oxidation of the vinyl group of Chl a into a formyl group to form Chl d was achieved using sodium borohydride (NaBH4) or ß-mercaptoethanol (BME/O2), respectively. During the consecutive reactions of Chl b and Chl f using a three-step procedure (1. NaBH4, 2. BME/O2, and 3. NaBH4) two new 7-hydroxymethyl Chl a species were prepared possessing the 3-formyl or 3-hydroxymethyl groups and three new 2-hydroxymethyl Chl a species possessing the 3-vinyl, 3-formyl, or 3-hydroxymethyl groups, respectively. Identification of the spectral properties of 2-hydroxymethyl Chl a may be biologically significant for deducing the latter stages of Chl f biosynthesis if the mechanism parallels Chl b biosynthesis. The spectral features and chromatographic properties of these modified Chls are important for identifying potential intermediates in the biosynthesis of Chls such as Chl f and Chl d and for identification of any new Chls in nature.

1-N-histidine phosphorylation of ChlD by the AAA+ ChlI2 stimulates magnesium chelatase activity in chlorophyll synthesis.

Magnesium chelatase (Mg-chelatase) inserts magnesium into protoporphyrin during the biosynthesis of chlorophyll and bacteriochlorophyll. Enzyme activity is reconstituted by forming two separate preactivated complexes consisting of a GUN4/ChlH/protoporphyrin IX substrate complex and a ChlI/ChlD enzyme 'motor' complex. Formation of the ChlI/ChlD complex in both Chlamydomonas reinhardtii and Oryza sativa is accompanied by phosphorylation of ChlD by ChlI, but the orthologous protein complex from Rhodobacter capsulatus, BchI/BchD, gives no detectable phosphorylation of BchD. Phosphorylation produces a 1-N-phospho-histidine within ChlD. Proteomic analysis indicates that phosphorylation occurs at a conserved His residue in the C-terminal integrin I domain of ChlD. Comparative analysis of the ChlD phosphorylation with enzyme activities of various ChlI/ChlD complexes correlates the phosphorylation by ChlI2 with stimulation of Mg-chelatase activity. Mutation of the H641 of CrChlD to E641 prevents both phosphorylation and stimulation of Mg-chelatase activity, confirming that phosphorylation at H641 stimulates Mg-chelatase. The properties of ChlI2 compared with ChlI1 of Chlamydomonas and with ChlI of Oryza, shows that ChlI2 has a regulatory role in Chlamydomonas.

GUN4-Protoporphyrin IX Is a Singlet Oxygen Generator with Consequences for Plastid Retrograde Signaling.

The genomes uncoupled 4 (GUN4) protein is a nuclear-encoded, chloroplast-localized, porphyrin-binding protein implicated in retrograde signaling between the chloroplast and nucleus, although its exact role in this process is still unclear. Functionally, it enhances Mg-chelatase activity in the chlorophyll biosynthesis pathway. Because GUN4 is present only in organisms that carry out oxygenic photosynthesis and because it binds protoporphyrin IX (PPIX) and Mg-PPIX, it has been suggested that it prevents production of light- and PPIX- or Mg-PPIX-dependent reactive oxygen species. A chld-1/GUN4 mutant with elevated PPIX has a light-dependent up-regulation of GUN4, implicating this protein in light-dependent sensing of PPIX, with the suggestion that GUN4 reduces PPIX-generated singlet oxygen, O2(a(1)Δg), and subsequent oxidative damage (Brzezowski, P., Schlicke, H., Richter, A., Dent, R. M., Niyogi, K. K., and Grimm, B. (2014) Plant J. 79, 285-298). In direct contrast, our results show that purified GUN4 and oxidatively damaged ChlH increase the rate of PPIX-generated singlet oxygen production in the light, by a factor of 5 and 10, respectively, when compared with PPIX alone. Additionally, the functional GUN4-PPIX-ChlH complex and ChlH-PPIX complexes generate O2(a(1)Δg) at a reduced rate when compared with GUN4-PPIX. As O2(a(1)Δg) is a potential plastid-to-nucleus signal, possibly through second messengers, light-dependent O2(a(1)Δg) generation by GUN4-PPIX is proposed to be part of a signal transduction pathway from the chloroplast to the nucleus. GUN4 thus senses the availability and flux of PPIX through the chlorophyll biosynthetic pathway and also modulates Mg-chelatase activity. The light-dependent O2(a(1)Δg) generation from GUN4-PPIX is thus proposed as the first step in retrograde signaling from the chloroplast to the nucleus.

Inducing the oxidative stress response in Escherichia coli improves the quality of a recombinant protein: magnesium chelatase ChlH.

The ∼150kDa ChlH subunit of magnesium chelatase from Oryza sativa, Hordeum vulgare and Chlamydomonas reinhardtii have been heterologously expressed in Escherichiacoli. The active soluble protein is found as both a multimeric and a monomeric form. The multimeric ChlH appears to be oxidatively damaged but monomer production is favoured in growth conditions that are known to cause an oxidative stress response in E.coli. Inducing an oxidative stress response may be of general utility to improve the quality of proteins expressed in E. coli. The similar responses of ChlH's from the three different species suggest that oligomerization of oxidatively damaged ChlH may have a functional role in the chloroplast, possibly as a signal of oxidative stress or damage.

Grandiose narcissism, unfounded beliefs, and behavioral reactions during the COVID-19 pandemic.

A theoretical perspective on grandiose narcissism suggests four forms of it (sanctity, admiration, heroism, rivalry) and states that these forms conduce to different ways of thinking and acting. Guided by this perspective, we examined in a multinational and multicultural study (61 countries; N = 15,039) how narcissism forms are linked to cognitions and behaviors prompted by the COVID-19 pandemic. As expected, differences in cognitions and behaviors across narcissism forms emerged. For example, higher narcissistic rivalry predicted lower likelihood of enactment of COVID-19 prevention behaviors, but higher narcissistic sanctity predicted higher likelihood of enactment of COVID-19 prevention behaviors. Further, whereas the heroism, admiration, and rivalry narcissism forms acted in a typically antisocial manner, with high narcissism predicting greater endorsement of unfounded health beliefs, the sanctity form acted in a prosocial manner, with higher narcissism being linked to lower endorsement of unfounded COVID-19 health beliefs. Thus, the findings (a) support the idea of four narcissism forms acting differently, and (b) show that these differences reflect a double-edged sword, sometimes linking to an anti-social orientation, and sometimes linking to a pro-social orientation.

Modeling the Characteristic Residues of Chlorophyll f Synthase (ChlF) from Halomicronema hongdechloris to Determine Its Reaction Mechanism.

Photosystem II (PSII) is a quinone-utilizing photosynthetic system that converts light energy into chemical energy and catalyzes water splitting. PsbA (D1) and PsbD (D2) are the core subunits of the reaction center that provide most of the ligands to redox-active cofactors and exhibit photooxidoreductase activities that convert quinone and water into quinol and dioxygen. The performed analysis explored the putative uncoupled electron transfer pathways surrounding P680+ induced by far-red light (FRL) based on photosystem II (PSII) complexes containing substituted D1 subunits in Halomicronema hongdechloris. Chlorophyll f-synthase (ChlF) is a D1 protein paralog. Modeling PSII-ChlF complexes determined several key protein motifs of ChlF. The PSII complexes included a dysfunctional Mn4CaO5 cluster where ChlF replaced the D1 protein. We propose the mechanism of chlorophyll f synthesis from chlorophyll a via free radical chemistry in an oxygenated environment created by over-excited pheophytin a and an inactive water splitting reaction owing to an uncoupled Mn4CaO5 cluster in PSII-ChlF complexes. The role of ChlF in the formation of an inactive PSII reaction center is under debate, and putative mechanisms of chlorophyll f biosynthesis are discussed.

The fear of COVID-19 scale: Its structure and measurement invariance across 48 countries.

Coronavirus disease (COVID-19) has been a source of fear around the world. We asked whether the measurement of this fear is trustworthy and comparable across countries. In particular, we explored the measurement invariance and cross-cultural replicability of the widely used Fear of COVID-19 scale (FCV-19S), testing community samples from 48 countries (N = 14,558). The findings indicate that the FCV-19S has a somewhat problematic structure, yet the one-factor solution is replicable across cultural contexts and could be used in studies that compare people who vary on gender and educational level. The validity of the scale is supported by a consistent pattern of positive correlations with perceived stress and general anxiety. However, given the unclear structure of the FCV-19S, we recommend using latent factor scores, instead of raw scores, especially in cross-cultural comparisons. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

The Anterior Attentional-Intentional System in Patients with Parkinson's Disease-A Pilot and Feasibility Study.

(1) Background: This study compared anterior attentional-intentional system performance between three groups: Parkinson's disease (PD) patients with normal cognition (PD-NC), with mild cognitive impairment (PD-MCI), and a comparison group (CG). It also evaluated the feasibility of the recruitment and study procedures; (2) Methods: From 45 participants recruited, 39 were allocated (mean age 65.31; 43.59% men) to PD-NC, PD-MCI and CG (13 per group). To assess attention, we used three tasks from the ROtman-Baycrest Battery for Investigating Attention: Simple Reaction time (RT), Choice RT, and Prepare RT. We conducted a mixed-model analysis of variance with a 3 (groups) × 4 (tasks) design to compare reaction times; (3) Results: PD-MCI had slower reaction times than PD-NC (p = 0.028) and the CG (p = 0.052); there was no difference between PD-NC and CG. PD-MCI might perform worse on monitoring tasks than PD-NC, Z = -1.68, p = 0.092. Nearly half the volunteers from the CG and 87% of all eligible patients were enrolled in the study and completed all neuropsychological procedures; (4) Conclusions: General cognitive decline appears related to partial deficits in energization and tends to impair attentional monitoring. Furthermore, PD-NC exhibited similar reaction times to the CG. Results from the feasibility study contributed to the definitive study.

S-adenosyl-L-methionine:magnesium-protoporphyrin IX O-methyltransferase from Rhodobacter capsulatus: mechanistic insights and stimulation with phospholipids.

The enzyme BchM (S-adenosyl-L-methionine:magnesium-protoporphyrin IX O-methyltransferase) from Rhodobacter capsulatus catalyses an intermediate reaction in the bacteriochlorophyll biosynthetic pathway. Overexpression of His(6)-tagged protein in Escherichia coli resulted in the majority of polypeptide existing as inclusion bodies. Purification from inclusion bodies was performed using metal-affinity chromatography after an elaborate wash step involving surfactant polysorbate-20. Initial enzymatic assays involved an in situ generation of S-adenosyl-L-methionine substrate using a crude preparation of S-adenosyl-L-methionine synthetase and this resulted in higher enzymatic activity compared with commercial S-adenosyl-L-methionine. A heat-stable stimulatory component present in the S-adenosyl-L-methionine synthetase was found to be a phospholipid, which increased enzymatic activity 3-4-fold. Purified phospholipids also stabilized enzymatic activity and caused a disaggregation of the protein to lower molecular mass forms, which ranged from monomeric to multimeric species as determined by size-exclusion chromatography. There was no stimulatory effect observed with magnesium-chelatase subunits on methyltransferase activity using His-BchM that had been stabilized with phospholipids. Substrate specificity of the enzyme was limited to 5-co-ordinate square-pyramidal metalloporphyrins, with magnesium-protoporphyrin IX being the superior substrate followed by zinc-protoporphyrin IX and magnesium-deuteroporphyrin. Kinetic analysis indicated a random sequential reaction mechanism. Three non-substrate metalloporphyrins acted as inhibitors with different modes of inhibition exhibited with manganese III-protoporphyrin IX (non-competitive or uncompetitive) compared with cobalt II-protoporphyrin IX (competitive).

C-terminal residues of oryza sativa GUN4 are required for the activation of the ChlH subunit of magnesium chelatase in chlorophyll synthesis.

Oryza sativa GUN4 together with the magnesium chelatase subunits ChlI, ChlD, and ChlH have been heterologously expressed and purified to reconstitute magnesium chelatase activity in vitro. Maximum magnesium chelatase activity requires pre-activation of OsChlH with OsGUN4, Mg(2+) and protoporphyrin-IX. OsGUN4 and OsChlH preincubated without protoporphyrin-IX yields magnesium chelatase activity similar to assays without OsGUN4, suggesting formation of a dead-end complex. Either 9 or 10 C-terminal amino acids of OsGUN4 are slowly hydrolyzed to yield a truncated OsGUN4. These truncated OsGUN4 still bind protoporphyrin-IX and Mg-protoporphyrin-IX but are unable to activate OsChlH. This suggests the mechanism of GUN4 activation of magnesium chelatase is different in eukaryotes compared to cyanobacteria as the orthologous cyanobacterial GUN4 proteins lack this C-terminal extension.

BchJ and BchM interact in a 1 : 1 ratio with the magnesium chelatase BchH subunit of Rhodobacter capsulatus.

Substrate channeling between the enzymatic steps in the (bacterio)chlorophyll biosynthetic pathway catalyzed by magnesium chelatase (BchI/ChlI, BchD/ChlD and BchH/ChlH subunits) and S-adenosyl-L-methionine:magnesium-protoporphyrin IX O-methyltransferase (BchM/ChlM) has been suggested. This involves delivery of magnesium-protoporphyrin IX from the BchH/ChlH subunit of magnesium chelatase to BchM/ChlM. Stimulation of BchM/ChlM activity by BchH/ChlH has previously been shown, and physical interaction of the two proteins has been demonstrated. In plants and cyanobacteria, there is an added layer of complexity, as Gun4 serves as a porphyrin (protoporphyrin IX and magnesium-protoporphyrin IX) carrier, but this protein does not exist in anoxygenic photosynthetic bacteria. BchJ may play a similar role to Gun4 in Rhodobacter, as it has no currently assigned function in the established pathway. Purified recombinant Rhodobacter capsulatus BchJ and BchM were found to cause a shift in the equilibrium amount of Mg-protoporphyrin IX formed in a magnesium chelatase assay. Analysis of this shift revealed that it was always in a 1 : 1 ratio with either of these proteins and the BchH subunit of the magnesium chelatase. The establishment of the new equilibrium was faster with BchM than with BchJ in a coupled magnesium chelatase assay. BchJ bound magnesium-protoporphyrin IX or formed a ternary complex with BchH and magnesium-protoporphyrin IX. These results suggest that BchJ may play a role as a general magnesium porphyrin carrier, similar to one of the roles of GUN4 in oxygenic organisms.

Kinetic analyses of the magnesium chelatase provide insights into the mechanism, structure, and formation of the complex.

The metabolic pathway known as (bacterio)chlorophyll biosynthesis is initiated by magnesium chelatase (BchI, BchD, BchH). This first step involves insertion of magnesium into protoporphyrin IX (proto), a process requiring ATP hydrolysis. Structural information shows that the BchI and BchD subunits form a double hexameric enzyme complex, whereas BchH binds proto and can be purified as BchH-proto. We utilized the Rhodobacter capsulatus magnesium chelatase subunits using continuous magnesium chelatase assays and treated the BchD subunit as the enzyme with both BchI and BchH-proto as substrates. Michaelis-Menten kinetics was observed with the BchI subunit, whereas the BchH subunit exhibited sigmoidal kinetics (Hill coefficient of 1.85). The BchI.BchD complex had intrinsic ATPase activity, and addition of BchH greatly increased ATPase activity. This was concentration-dependent and gave sigmoidal kinetics, indicating there is more than one binding site for the BchH subunit on the BchI.BchD complex. ATPase activity was approximately 40-fold higher than magnesium chelatase activity and continued despite cessation of magnesium chelation, implying one or more secondary roles for ATP hydrolysis and possibly an as yet unknown switch required to terminate ATPase activity. One of the secondary roles for BchH-stimulated ATP hydrolysis by a BchI.BchD complex is priming of BchH to facilitate correct binding of proto to BchH in a form capable of participating in magnesium chelation. This porphyrin binding is the rate-limiting step in catalysis. These data suggest that ATP hydrolysis by the BchI.BchD complex causes a series of conformational changes in BchH to effect substrate binding, magnesium chelation, and product release.

Recessiveness and dominance in barley mutants deficient in Mg-chelatase subunit D, an AAA protein involved in chlorophyll biosynthesis.

Mg-chelatase catalyzes the insertion of Mg2+ into protoporphyrin IX at the first committed step of the chlorophyll biosynthetic pathway. It consists of three subunits: I, D, and H. The I subunit belongs to the AAA protein superfamily (ATPases associated with various cellular activities) that is known to form hexameric ring structures in an ATP-dependant fashion. Dominant mutations in the I subunit revealed that it functions in a cooperative manner. We demonstrated that the D subunit forms ATP-independent oligomeric structures and should also be classified as an AAA protein. Furthermore, we addressed the question of cooperativity of the D subunit with barley (Hordeum vulgare) mutant analyses. The recessive behavior in vivo was explained by the absence of mutant proteins in the barley cell. Analogous mutations in Rhodobacter capsulatus and the resulting D proteins were studied in vitro. Mixtures of wild-type and mutant R. capsulatus D subunits showed a lower activity compared with wild-type subunits alone. Thus, the mutant D subunits displayed dominant behavior in vitro, revealing cooperativity between the D subunits in the oligomeric state. We propose a model where the D oligomer forms a platform for the stepwise assembly of the I subunits. The cooperative behavior suggests that the D oligomer takes an active part in the conformational dynamics between the subunits of the enzyme.