A bacterial secretosome for regulated envelope biogenesis and quality control

As the first line of defence against antibiotics, the Gram-negative bacterial envelope and its biogenesis are of considerable interest to the microbiological and biomedical communities. All bacterial proteins are synthesised in the cytosol, so inner- and outer-membrane proteins, and periplasmic residents have to be transported to their final destinations via specialised protein machinery. The Sec translocon, a ubiquitous integral inner-membrane (IM) complex, is key to this process as the major gateway for protein transit from the cytosol to the cell envelope; this can be achieved during their translation, or afterwards. Proteins need to be directed to the inner-membrane (usually co-translational), otherwise SecA utilises ATP and the proton-motive-force (PMF) to drive proteins across the membrane post-translationally. These proteins are then picked up by chaperones for folding in the periplasm or delivered to the β-barrel assembly machinery (BAM) for incorporation into the outer-membrane. The core heterotrimeric SecYEG-complex forms the hub for an extensive network of interactions that regulate protein delivery and quality control. Here, we conduct a biochemical exploration of this secretosome: a very large, versatile and inter-changeable assembly with the Sec-translocon at its core; featuring interactions that facilitate secretion (SecDF), inner- and outer-membrane protein insertion (respectively, YidC and BAM), protein folding and quality control (e.g. PpiD, YfgM and FtsH). We propose the dynamic interplay amongst these and other factors act to ensure efficient whole envelope biogenesis, regulated to accommodate the requirements of cell elongation and division. This organisation would be essential for cell wall biogenesis and remodelling and thus its perturbation would be a good strategy for the development of anti-microbials.

The Danaid Theory of Aging

The classical evolutionary theories of aging suggest that aging evolves due to insufficient selective pressure against it. In these theories, declining selection pressure with age leads to aging through genes or resource allocations, implying that aging could potentially be stalled were genes, resource allocation, or selection pressure somewhat different. While these classical evolutionary theories are undeniably part of a description of the evolution of aging, they do not explain the diversity of aging patterns, and they do not constitute the only possible evolutionary explanation. Without denying selection pressure a role in the evolution of aging, we argue that the origin and diversity of aging should also be sought in the nature and evolution of organisms that are, from their very physiological make up, unmaintainable. Drawing on advances in developmental biology, genetics, biochemistry, and complex systems theory since the classical theories emerged, we propose a fresh evolutionary-mechanistic theory of aging, the Danaid theory. We argue that, in complex forms of life like humans, various restrictions on maintenance and repair may be inherent, and we show how such restrictions are laid out during development. We further argue that there is systematic variation in these constraints across taxa, and that this is a crucial factor determining variation in aging and lifespan across the tree of life. Accordingly, the core challenge for the field going forward is to map and understand the mosaic of constraints, trade-offs, chance events, and selective pressures that shape aging in diverse ways across diverse taxa.

The face never lies: facial expressions and mimicry modulate playful interactions in wild geladas

Play fighting, the most common form of social play in mammals, is a fertile field to investigate the use of visual signals in animals’ communication systems. Visual signals can be exclusively emitted during play (e.g. play faces, PF, context-dependent signals), or they can be released under several behavioural domains (e.g. lip-smacking, LS, context-independent signals). Rapid facial mimicry (RFM) is the involuntary rapid facial congruent response produced after perceiving others’ facial expressions. RFM leads to behavioural and emotional synchronisation that often translates into the most balanced and longest playful interactions. Here, we investigate the role of playful communicative signals in geladas (Theropithecus gelada). We analysed the role of PF and LS produced by wild immature geladas during play fighting. We found that PFs, but not LS, were particularly frequent during the riskiest interactions such as those including individuals from different groups. Furthermore, we found that RFM (PF→PF) was highest when playful offensive patterns were not biased towards one of the players and when the session was punctuated by LS. Under this perspective, the presence of context-independent signals such as LS may be useful in creating an affiliative mood that enhances communication and facilitates most cooperative interactions. Indeed, we found that sessions punctuated by the highest frequency of RFM and LS were also the longest ones. Whether the complementary use of PF and LS is strategically guided by the audience or is the result of the emotional arousal experienced by players remains to be investigated. Significance Statement Facial expressions and their rapid replication by an observer are fundamental communicative tools during social contacts in human and non-human animals. Play fighting is one of the most complex forms of social interactions that can easily lead to misunderstanding if not modulated through an accurate use of social signals. Wild immature geladas are able to manage their play sessions thus limiting the risk of aggressive escalation. While playing with unfamiliar subjects belonging to other groups, they make use of a high number of play faces. Moreover, geladas frequently replicate others’ play faces and emit facial expressions of positive intent (i.e. lip-smacking) when engaging in well-balanced long play sessions. In this perspective, this “playful facial chattering” creates an affiliative mood that enhances communication and facilitates most cooperative interactions.

A Socio Semiotic Approach to Multimodal Discourse of Selected Nollywood Film Advertisement Posters

Film posters are complex forms of visual communication basically employed to promote films so as to seek for patronage from prospective viewers. Nollywood film poster designers or marketers employ a complex system of modes of multimodal communication to achieve their intended objectives. This study therefore investigates how these semiotic resources reveal the intention of the film poster designers and how other contextual variables influence the ability of the viewers to comprehend the messages embedded in film posters. The objectives of the study are to uncover the visual and linguistic semiotic resources in the film advertisement posters and their interaction. The study adopts a qualitative approach to the analyses of six randomly selected Nollywood film advertisement posters of three genres, namely: drama, thriller and comedy. Yuen’s Generic Structure Potential and Royce’s Ideational Intersemiotic Complementarity serve as the basis for the analysis of the selected texts. The study reveals that visual modes are more salient and frequently employed in the advertisement posters than the linguistic modes. However, both the visual and the linguistic modes offer complementary relationship for effective meaning-making in the selected Nollywood advertisement posters. The meanings derived are often contextual which appeal to the audience reasoning and sustain their interests. The study concludes by emphasizing the importance of the synergy of both linguistic and visual multimodal resources or modes of signification in the successful meaning-making and meaning-comprehension in the study of visual communication.

Decoding key transient inter-catalyst interactions in a metallaphotoredox-catalysed cross-electrophile coupling reaction

Metallaphotoredox chemistry has recently witnessed a renaissance through the use of abundant first-row transition metals combined with suitable photocatalysts. The intricate details arising from the combination of two (or more) catalytic components during the reaction and specially the inter-catalyst interactions remain poorly understood. As a representative example of a catalytic process featuring such intricacies, we here present a meticulous study of the mechanism of a cobalt-organophotoredox catalysed allylation of aldehydes. Importantly, the commonly proposed elementary steps in reductive metallaphotoredox chemistry are more complex than previously assumed. After initial reductive quenching, a transient charge-transfer complex forms that interacts with both the transition-metal catalyst, as well as the catalytic base. Surprisingly, the former interaction leads to deactivation due to induced charge recombination, while the latter promotes deprotonation of the electron donor, which is a crucial step in order to promote productive catalysis, but is often neglected. Due to the low efficiency of this process, the overall catalytic reaction is photon-limited and the cobalt catalyst remains in a dual resting state awaiting photoinduced reduction. These new insights are of general importance to the synthetic community, as photoredox chemistry has become a powerful tool used in the creation of elusive compounds through carbon-carbon bond formations. Understanding the underlying factors that determine the efficiency of such reactions provides a conceptually stronger reactivity paradigm to empower future approaches to synthetic challenges that rely on dual metallaphotoredox catalysis.

Visual syntax in social media

Modern technologies have fundamentally changed the sphere of communication. One of the interesting social media characteristics is the prevalence of the visual transmission mode. Regardless of the fact that photo-rhetoric in social networks usually lacks complexity and is often limited to the statement of facts, there exist more complex forms of visual syntax. The article analyses the options for creating a twofold semantic conception of images, enabling communication to expand temporally. Moreover, there have been demonstrated the visual metaphors in social networks as exemplified by 2020 gestalt.

The Solar System: Nature and Mechanics

Origin, mechanics and properties of the Solar System are analyzed in the framework of Complete Relativity. The analysis confirms the postulates and hypotheses of the theory with a high degree of confidence. During the analysis, some new hypotheses have emerged. These are discussed and confirmed with various degrees of confidence. To increase confidence or refute some hypotheses, experimental verification is necessary. Main conclusions are: - Solar System is a scaled Carbon isotope with a nucleus in a condensed (bosonic) state and components in various vertically excited states, - Earth is a living being of extremely introverted intelligence, life is common everywhere, albeit extroverted complex forms are present on planetary surfaces only during planetary neurogenesis, - anthropogenic climate change is only a part (trigger from one perspective) of bigger global changes on Earth and in the Solar System during planetary neurogenesis, - major extinction events are relative extinctions, a regular part of transformation and transfer of life in the process of planetary neurogenesis.

Stochastic approximation cut algorithm for inference in modularized Bayesian models

Bayesian modelling enables us to accommodate complex forms of data and make a comprehensive inference, but the effect of partial misspecification of the model is a concern. One approach in this setting is to modularize the model and prevent feedback from suspect modules, using a cut model. After observing data, this leads to the cut distribution which normally does not have a closed form. Previous studies have proposed algorithms to sample from this distribution, but these algorithms have unclear theoretical convergence properties. To address this, we propose a new algorithm called the stochastic approximation cut (SACut) algorithm as an alternative. The algorithm is divided into two parallel chains. The main chain targets an approximation to the cut distribution; the auxiliary chain is used to form an adaptive proposal distribution for the main chain. We prove convergence of the samples drawn by the proposed algorithm and present the exact limit. Although SACut is biased, since the main chain does not target the exact cut distribution, we prove this bias can be reduced geometrically by increasing a user-chosen tuning parameter. In addition, parallel computing can be easily adopted for SACut, which greatly reduces computation time.

Right to education – young people with disabilities and children with special educational needs

One of the biggest educational challenges of the past decades is the question of the social and educational integration of young people with special educational needs (SEN) and/or youth and young adults with disabilities. The importance of the topic is provided by two factors; there is a clearly rising trend in the increase in the number of children with special educational needs, which can be identified almost immediately among the children due to the methodological results, on the one hand, and it has become a feature of the public education that was able to launch many segments of the market – developments, movement therapy, complex forms of education based on special needs – and, as a result, industries are slowly beginning to emerge to create opportunities for them to enter the system, on the other hand. In the case of the public education, the SEN category also represents a kind of set of problems, because in the case of students who study at a normal pace, those belonging to the SEN group only experience disadvantages. The purpose of this summary is, on the one hand, to describe the concept and the framework of the content of the special educational needs used in the public education, and, on the other hand, to summarize the types of disabilities in the light of such data. The study also seeks to give an answer to the question how the determination of the disability is able to reflect a specific educational need, and shed light on the usable, more relevant concept from the perspective of the interested persons.

Consciousness as a multidimensional phenomenon: implications for the assessment of disorders of consciousness

Disorders of consciousness (DoCs) pose a significant clinical and ethical challenge because they allow for complex forms of conscious experience in patients where intentional behaviour and communication are highly limited or non-existent. There is a pressing need for brain-based assessments that can precisely and accurately characterize the conscious state of individual DoC patients. There has been an ongoing research effort to develop neural measures of consciousness. However, these measures are challenging to validate not only due to our lack of ground truth about consciousness in many DoC patients but also because there is an open ontological question about consciousness. There is a growing, well-supported view that consciousness is a multidimensional phenomenon that cannot be fully described in terms of the theoretical construct of hierarchical, easily ordered conscious levels. The multidimensional view of consciousness challenges the utility of levels-based neural measures in the context of DoC assessment. To examine how these measures may map onto consciousness as a multidimensional phenomenon, this article will investigate a range of studies where they have been applied in states other than DoC and where more is known about conscious experience. This comparative evidence suggests that measures of conscious level are more sensitive to some dimensions of consciousness than others and cannot be assumed to provide a straightforward hierarchical characterization of conscious states. Elevated levels of brain complexity, for example, are associated with conscious states characterized by a high degree of sensory richness and minimal attentional constraints, but are suboptimal for goal-directed behaviour and external responsiveness. Overall, this comparative analysis indicates that there are currently limitations to the use of these measures as tools to evaluate consciousness as a multidimensional phenomenon and that the relationship between these neural signatures and phenomenology requires closer scrutiny.