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Epilepsy, characterized by recurrent seizures, impacts 70–80% of patients, leading to cognitive deficits. The intricate relationship between seizure control and cognitive impairment remains complex. Epileptic encephalopathy (EE), an intensified form often rooted in genetic factors, is detectable through next-generation sequencing, aiding in precise diagnoses, family counseling, and potential treatment strategies. We present a case involving two sisters with refractory generalized seizures evolving into dysarthria, dysphagia, ataxia, and cognitive decline. Despite normal physical exams, abnormal electroencephalogram results consistent with epilepsy were noted. Whole Exome Sequencing identified heterozygous variants in the alanyl-tRNA synthetase (AARS) and Calcium Voltage-Gated Channel Subunit Alpha 1 (CACNA1A) genes. The AARS variant (c.C2083T, p.R695*) was maternal, while the CACNA1A variant (c.G7400C, p.R2467P) was paternal. Patients A and B exhibited a unique blend of neurological and psychiatric conditions, distinct from common disorders that begin adolescence, like Juvenile Myoclonic Epilepsy. Whole Exome Sequencing uncovered an AARS gene and CACNA1A gene, linked to various autosomal dominant phenotypes. Presence in both parents, coupled with familial reports of migraines and seizures, provides insight into accelerated symptom progression. This study underscores the importance of genetic testing in decoding complex phenotypes and emphasizes the value of documenting family history for anticipating related symptoms and future health risks. [ABSTRACT FROM AUTHOR]

Epilepsy, characterized by recurrent seizures, impacts 70–80% of patients, leading to cognitive deficits. The intricate relationship between seizure control and cognitive impairment remains complex. Epileptic encephalopathy (EE), an intensified form often rooted in genetic factors, is detectable through next-generation sequencing, aiding in precise diagnoses, family counseling, and potential treatment strategies. We present a case involving two sisters with refractory generalized seizures evolving into dysarthria, dysphagia, ataxia, and cognitive decline. Despite normal physical exams, abnormal electroencephalogram results consistent with epilepsy were noted. Whole Exome Sequencing identified heterozygous variants in the alanyl-tRNA synthetase (AARS) and Calcium Voltage-Gated Channel Subunit Alpha 1 (CACNA1A) genes. The AARS variant (c.C2083T, p.R695*) was maternal, while the CACNA1A variant (c.G7400C, p.R2467P) was paternal. Patients A and B exhibited a unique blend of neurological and psychiatric conditions, distinct from common disorders that begin adolescence, like Juvenile Myoclonic Epilepsy. Whole Exome Sequencing uncovered an AARS gene and CACNA1A gene, linked to various autosomal dominant phenotypes. Presence in both parents, coupled with familial reports of migraines and seizures, provides insight into accelerated symptom progression. This study underscores the importance of genetic testing in decoding complex phenotypes and emphasizes the value of documenting family history for anticipating related symptoms and future health risks.

Aminoacyl-tRNA synthetases (aaRSs) catalyze the ligation of amino acids to cognate tRNAs by consuming one molecule of ATP. Magnesium is essential for the enzymes’ activity. Certain class II aaRSs, such as lysyl-tRNA synthetase (LysRS) and seryl-tRNA synthetase (SerRS), recognize ATP together with three magnesium ions in the active site. The detailed role of how these magnesium ions facilitate the ATP recognition by the enzyme is unclear. Here, we report analyses of a crystal structure of human LysRS, in which the two enzymatic pockets of the LysRS dimer are in different states. One pocket is vacant of ATP, and the other is in an intermediate state of ATP recognition. Interestingly, only one magnesium ion instead of three is bound in both states. Compared with our previously solved LysRS structures, we proposed the order of binding for the three magnesium ions. These structures also reveal multiple intermediate ATP-bound states during the amino acid activation reaction, providing critical insights into the mechanisms of the magnesium-dependent enzyme activity of class II aaRSs.

Cell-free biology is increasingly utilized for engineering biological systems, incorporating novel functionality, and circumventing many of the complications associated with cells. The central dogma describes the information flow in biology consisting of transcription and translation steps to decode genetic information. Aminoacyl tRNA synthetases (AARSs) and tRNAs are key components involved in translation and thus protein synthesis. This review provides information on AARSs and tRNA biochemistry, their role in the translation process, summarizes progress in cell-free engineering of tRNAs and AARSs, and discusses prospects and challenges lying ahead in cell-free engineering.

Primary microglial leukodystrophy or leukoencephalopathy are disorders in which a genetic defect linked to microglia causes cerebral white matter damage. Pigmented orthochromatic leukodystrophy, adult-onset orthochromatic leukodystrophy associated with pigmented macrophages, hereditary diffuse leukoencephalopathy with (axonal) spheroids, and adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) are different terms apparently used to designate the same disease. However, ALSP linked to dominantly inherited mutations in CSF1R (colony stimulating factor receptor 1) cause CSF-1R-related leukoencephalopathy (CRP). Yet, recessive ALSP with ovarian failure linked to AARS2 (alanyl-transfer (t)RNA synthase 2) mutations (LKENP) is a mitochondrial disease and not a primary microglial leukoencephalopathy. Polycystic membranous lipomembranous osteodysplasia with sclerosing leukoencephalopathy (PLOSL; Nasu–Hakola disease: NHD) is a systemic disease affecting bones, cerebral white matter, selected grey nuclei, and adipose tissue The disease is caused by mutations of one of the two genes TYROBP or TREM2, identified as PLOSL1 and PLOSL2, respectively. TYROBP associates with receptors expressed in NK cells, B and T lymphocytes, dendritic cells, monocytes, macrophages, and microglia. TREM2 encodes the protein TREM2 (triggering receptor expressed on myeloid cells 2), which forms a receptor signalling complex with TYROBP in macrophages and dendritic cells. Rather than pure microglial leukoencephalopathy, NHD can be considered a multisystemic "immunological" disease. [ABSTRACT FROM AUTHOR]

Atlantoaxial rotatory subluxation (AARS) is a rare outcome of trauma in adults. We present a case of a 38-year-old female who presented with neck pain and stiffness after a mild trauma. On exam the patient had a “cock-robin” position, comparable to acute torticollis. Computerized tomography demonstrated findings consistent with AARS. Reduction was performed in the emergency department and the patient had no further neurological sequelae. Recognition of AARS after trauma requires a high index of suspicion and early diagnosis is important to best patient outcomes.

Abstract Swedish type Hereditary Diffuse Leukoencephalopathy with Spheroids (HDLS-S) is a severe adult-onset leukoencephalopathy with the histopathological hallmark of neuraxonal degeneration with spheroids, described in a large family with a dominant inheritance pattern. The initial stage of the disease is dominated by frontal lobe symptoms that develop into a rapidly advancing encephalopathy with pyramidal, deep sensory, extrapyramidal and optic tract symptoms. Median survival is less than 10 years. Recently, pathogenic mutations in CSF1R were reported in a clinically and histologically similar leukoencephalopathy segregating in several families. Still, the cause of HDLS-S remained elusive since its initial description in 1984, with no CSF1R mutations identified in the family. Here we update the original findings associated with HDLS-S after a systematic and recent assessment of several family members. We also report the results from exome sequencing analyses indicating the p.Cys152Phe variant in the alanyl tRNA synthetase (AARS) gene as the probable cause of this disease. The variant affects an amino acid located in the aminoacylation domain of the protein and does not cause differences in splicing or expression in the brain. Brain pathology in one case after 10 years of disease duration showed the end stage of the disease to be characterized by widespread liquefaction of the white matter leaving only some macrophages and glial cells behind the centrifugally progressing front. These results point to AARS as a candidate gene for rapidly progressing adult-onset CSF1R-negative leukoencephalopathies.

Aminoacyl-RNA synthetases (aaRSs) are among the key enzymes of protein biosynthesis. They are responsible for conducting the first step in the protein biosynthesis, namely attaching amino acids to the corresponding tRNA molecules both in cytoplasm and mitochondria. More and more research demonstrates that mutations in the genes encoding aaRSs lead to the development of various neurodegenerative diseases, such as incurable Charcot–Marie–Tooth disease (CMT) and distal spinal muscular atrophy. Some mutations result in the loss of tRNA aminoacylation activity, while other mutants retain their classical enzyme activity. In the latter case, disease manifestations are associated with additional neuron-specific functions of aaRSs. At present, seven aaRSs (GlyRS, TyrRS, AlaRS, HisRS, TrpRS, MetRS, and LysRS) are known to be involved in the CMT etiology with glycyl-tRNA synthetase (GlyRS) being the most studied of them. [ABSTRACT FROM AUTHOR]

Mitochondrial diseases are a clinically heterogeneous group of multisystemic disorders that arise as a result of various mitochondrial dysfunctions. Autosomal recessive aARS deficiencies represent a rapidly growing group of severe rare inherited mitochondrial diseases, involving multiple organs, and currently without curative option. They might be related to defects of mitochondrial aminoacyl t-RNA synthetases (mtARS) that are ubiquitous enzymes involved in mitochondrial aminoacylation and the translation process. Here, using NGS analysis of 281 nuclear genes encoding mitochondrial proteins, we identified 4 variants in different mtARS in three patients from unrelated Tunisian families, with clinical features of mitochondrial disorders. Two homozygous variants were found in KARS (c.683C>T) and AARS2 (c.1150-4C>G), respectively in two patients, while two heterozygous variants in EARS2 (c.486-7C>G) and DARS2 (c.1456C>T) were concomitantly found in the third patient. Bio-informatics investigations predicted their pathogenicity and deleterious effects on pre-mRNA splicing and on protein stability. Thus, our results suggest that mtARS mutations are common in Tunisian patients with mitochondrial diseases. [ABSTRACT FROM AUTHOR]

Adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) is an adult-onset, inherited white matter disorder encompassing two previously identified clinicopathologically similar entities: pigmentary orthochromatic leukodystrophy (POLD) and hereditary diffuse leukoencephalopathy with spheroids (HDLS). In this chapter, we discuss how advances in our genetic understanding of the condition have further delineated three distinct clinical entities within ALSP, namely CSF1R-related ALSP, AARS2-related leukoencephalopathy (AARS2-L), and AARS (HDLS-S). We provide descriptions of the clinical, radiologic, pathologic, and pathophysiologic findings in each entity, detailing their similarities and differences, and discuss current and future treatment options where available., (Copyright © 2024 Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.)

Mutations in genes encoding aminoacyl‐tRNA synthetases have been reported in several neurological disorders. KARS is a dual localized lysyl‐tRNA synthetase and its cytosolic isoform belongs to the multiple aminoacyl‐tRNA synthetase complex (MSC). Biallelic mutations in the KARS gene were described in a wide phenotypic spectrum ranging from nonsyndromic deafness to complex impairments. Here, we report on a patient with severe neurological and neurosensory disease investigated by whole‐exome sequencing and found to carry biallelic mutations c.683C>T (p.Pro228Leu) and c.871T>G (p.Phe291Val), the second one being novel, in the KARS gene. The patient presented with an atypical clinical presentation with an optic neuropathy not previously reported. At the cellular level, we show that cytoplasmic KARS was expressed at a lower level in patient cells and displayed decreased interaction with MSC. In vitro, these two KARS variants have a decreased aminoacylation activity compared with wild‐type KARS, the p.Pro228Leu being the most affected. Our data suggest that dysfunction of cytoplasmic KARS resulted in a decreased level of translation of the nuclear‐encoded lysine‐rich proteins belonging to the respiratory chain complex, thus impairing mitochondria functions. [ABSTRACT FROM AUTHOR]

The Eastern Mediterranean Sea (EMS) is an ultraoligotrophic semi-enclosed sea with low nutrient levels, low primary production rate, impoverished phytoplankton populations and low zooplankton standing stocks. The Cretan Passage in the western Levantine Sea is one of the least explored areas of the EMS. We measured the mesozooplankton biomass, abundance and taxon composition as well as biochemical parameters like Εlectron Τransport System (ETS) activity and Aminoacyl-tRNA Synthetases (AARS) activities in late spring of 2016 (28 March–17 April 2016). The sampling area is influenced by the presence of the permanent Rhodes Cyclonic Gyre east of Crete and a series of smaller permanent or recurrent gyres south of Crete which influence the pathway of the Atlantic Water from the Ionian Sea towards the Levantine Basin at surface and subsurface layers. Mesozooplankton abundance showed slightly increasing values from western to eastern stations of the Cretan Passage and although subsurface maxima were recorded in the 50–100 m layer, the abundance at all stations generally decreased with depth. The community was dominated by copepods at all stations. Juveniles of Clausocalanus followed by juveniles of Oithona and the Oncaea media group (Oncaea waldemari, Oncaea scottodicarloi, Oncaea media) were the most abundant taxa in the upper layer, whereas Mormonilla minor , Haloptilus longicornis and Subeucalanus monachus were mainly found below 100 m. ETS, AARS and biomass for carbon measurements were conducted in the same area for the 0–100 m and 0–500 m layers. ETS was highest at LV13 with 10.56 ± 1.33 μl O 2 h−1 mg protein−1 in 0–500 m and carbon biomass was highest at LV18 with 4.99 mg m−3 in 0–100 m. Lowest values of 4.52 ± 1.46 μl O 2 h−1 mg protein−1 at LV18 in 0–100 m were detected for ETS and 0.91 mg m−3 at LV10 in 0–500 m for carbon biomass. Specific AARS activities showed no significant differences among sites. On the basis of ETS and AARS, we calculated that the zooplankton carbon requirements follow the west to east trend of zooplankton biomass, however, the zooplankton is not well fed and the organisms are living under oligotrophic stress. [ABSTRACT FROM AUTHOR]

Knowledge of metabolic rates of euphausiid diel vertical migrants in the ocean is of paramount importance to understand the role of these organisms in the downward transport of carbon due to their feeding in the epipelagic zone and subsequent respiration, egestion, excretion and mortality in the mesopelagic zone. Enzymatic activities are used as proxies for the estimation of metabolism in deep waters because of the logistical problems related to measure these rates at depth. However, metabolic activities of euphausiids in the so-called oxygen minimum zones (OMZs) are still not well understood. The OMZs are expanding as the effect of the global warming. Knowledge about the metabolic response of organisms transiting these zones will help to understand the fate of zooplanktonic communities and vertical active flux. The electron transport system (ETS) and aminoacyl-tRNA synthetases (AARS) activities were used as proxies for potential respiration and growth in planktonic organisms. Here, we measured these enzymatic activities in Euphausia distinguenda in the well-oxygenated epipelagic layer and in the OMZ of the northern boundary of the Eastern Tropical Pacific off Mexico. E. distinguenda was found in the mixed layer at night (~3.5 mL O2 L−1) and near the core of the OMZ (0.2 mL O2 L−1) during daytime between 200 and 350 m depth. We found higher ETS and AARS specific activities in the warm mixed layer at night and significantly lower in the colder OMZ during daytime because of temperature differences. However, when the effect of temperature was subtracted in both enzyme activities, higher values in the mesopelagic layer were observed. This result is tentatively explained by the increase in substrates as the effect of feeding at night in the upper layers and their oxygen consumption at depth during day in order to compensate for the colder temperature and low dissolved oxygen concentration. This physiological mechanism allows E. distinguenda diel vertical migrants to partly face the physical constraints of vertical migration imposed to avoid predators. [ABSTRACT FROM AUTHOR]

Highlights • Wild type AARS is localized in the cytoplasmic region. • The CMT2 N-associated AARS mutant is localized throughout the organelles. • The mutant inhibits differentiation in N1E-115 cells. • Valproic acid reverses the effect of the CMT2 N-associated AARS mutant. Abstract Charcot-Marie-Tooth (CMT) disease is composed of a heterogeneous group of hereditary peripheral neuropathies. The peripheral nervous system primarily comprises two types of cells: neuronal cells and myelinating glial Schwann cells. CMT2 N is an autosomal dominant disease and its responsible gene encodes alanyl-tRNA synthetase (AARS), which is a family of cytoplasmic aminoacyl-tRNA synthetases. CMT2 N is associated with the mutation, including a missense mutation, which is known to decrease the enzymatic activity of AARS, but whether and how its mutation affects AARS localization and neuronal process formation remains to be understood. First, we show that the AARS mutant harboring Asn71-to-Tyr (N71Y) is not localized in cytoplasm. The expression of AARS mutant proteins in COS-7 cells mainly leads to localization into lysosome, whereas the wild type is indeed localized in cytoplasm. Second, in N1E-115 cells as the neuronal cell model, cells expressing the N71Y mutant do not have the ability to grow processes. Third, pretreatment with antiepileptic valproic acid reverses the inhibitory effect of the N71Y mutant on process growth. Taken together, the N71Y mutation of AARS leads to abnormal intracellular localization, inhibiting process growth, yet this inhibition is reversed by valproic acid. [ABSTRACT FROM AUTHOR]

Highlights • Zooplankton migrant biomass and active carbon export doubled in the Alboran Sea WAG. • Diel migrants production in the WAG equaled coastal epipelagic zooplankton production. • Active flux by DVM exceeded the estimated phytoplankton sinking flux within the WAG. • Mesoscale eddies must be included in future models of the biological carbon pump. • The Alboran Sea occidental basin acts as sink of atmospheric carbon in summer. Abstract The distribution of marine productivity in the Alboran Sea responds strongly to its hydrodynamics, shaped by the influence of the Atlantic jet that enters through the Gibraltar Strait. This stream originates an oligotrophic western anticyclonic gyre (WAG) that dominates the western basin of the Alboran Sea. We studied vertical (0–900 m) diel changes in zooplankton biomass, potential respiration (electron transport system activity, ETS) and growth rates (aminoacyl-tRNA synthetases activity, AARS), to assess their variability in relation to the WAG structure. Zooplankton biomass was distributed in distinctive layers and we observed strong diel vertical migrations in the open sea. Diel vertical migrants (DVM) biomass, production and respiration rates doubled within the WAG core. The active carbon flux to mesopelagic waters mediated by DVM, estimated from respiration and mortality at depth, increased from the coast (2.0–5.7 mg C m−2 d−1) towards the gyre core (27.1–76.7 mg C m−2 d−1). The WAG enhanced the carbon export to deep waters, reinforcing the role of the Alboran Sea as sink of atmospheric carbon. [ABSTRACT FROM AUTHOR]

Prokaryotic and eukaryotic cytosolic aminoacyl-tRNA synthetases (aaRSs) are essentially known for their conventional function of generating the full set of aminoacyl-tRNA species that are needed to incorporate each organism's repertoire of genetically-encoded amino acids during ribosomal translation of messenger RNAs. However, bacterial and eukaryotic cytosolic aaRSs have been shown to exhibit other essential nonconventional functions. Here we review all the subcellular compartments that prokaryotic and eukaryotic cytosolic aaRSs can reach to exert either a conventional or nontranslational role. We describe the physiological and stress conditions, the mechanisms and the signaling pathways that trigger their relocation and the new functions associated with these relocating cytosolic aaRS. Finally, given that these relocating pools of cytosolic aaRSs participate to a wide range of cellular pathways beyond translation, but equally important for cellular homeostasis, we mention some of the pathologies and diseases associated with the dis-regulation or malfunctioning of these nontranslational functions. [ABSTRACT FROM AUTHOR]

Aminoacyl-transfer RNA (tRNA) synthetases ligate amino acids to specific tRNAs and are essential for protein synthesis. Although alanyl-tRNA synthetase (AARS) is a synthetase implicated in a wide range of neurological disorders from Charcot-Marie-Tooth disease to infantile epileptic encephalopathy, there have been limited data on their pathogenesis. Here, we report loss-of-function mutations in AARS in two siblings with progressive microcephaly with hypomyelination, intractable epilepsy, and spasticity. Whole-exome sequencing identified that the affected individuals were compound heterozygous for mutations in AARS gene, c.2067dupC (p.Tyr690Leufs*3) and c.2738G>A (p.Gly913Asp). A lymphoblastoid cell line developed from one of the affected individuals showed a strong reduction in AARS abundance. The mutations decrease aminoacylation efficiency by 70%-90%. The p.Tyr690Leufs*3 mutation also abolished editing activity required for hydrolyzing misacylated tRNAs, thereby increasing errors during aminoacylation. Our study has extended potential mechanisms underlying AARS-related disorders to include destabilization of the protein, aminoacylation dysfunction, and defective editing activity. [ABSTRACT FROM AUTHOR]

The tRNA identity elements for some amino acids are distinct between the bacterial and archaeal domains. Searching in recent genomic and metagenomic sequence data, we found some candidate phyla radiation (CPR) bacteria with archaeal tRNA identity for Tyr-tRNA and Trp-tRNA synthesis. These bacteria possess genes for tyrosyl-tRNA synthetase (TyrRS) and tryptophanyl-tRNA synthetase (TrpRS) predicted to be derived from DPANN superphylum archaea, while the cognate tRNATyr and tRNATrp genes reveal bacterial or archaeal origins. We identified a trace of domain fusion and swapping in the archaeal-type TyrRS gene of a bacterial lineage, suggesting that CPR bacteria may have used this mechanism to create diverse proteins. Archaeal-type TrpRS of bacteria and a few TrpRS species of DPANN archaea represent a new phylogenetic clade (named TrpRS-A). The TrpRS-A open reading frames (ORFs) are always associated with another ORF (named ORF1) encoding an unknown protein without global sequence identity to any known protein. However, our protein structure prediction identified a putative HIGH-motif and KMSKS-motif as well as many α-helices that are characteristic of class I aminoacyl-tRNA synthetase (aaRS) homologs. These results provide another example of the diversity of molecular components that implement the genetic code and provide a clue to the early evolution of life and the genetic code. [ABSTRACT FROM AUTHOR]

By definition, cytosolic aminoacyl-tRNA synthetases (aaRSs) should be restricted to the cytosol of eukaryotic cells where they supply translating ribosomes with their aminoacyl-tRNA substrates. However, it has been shown that other translationally-active compartments like mitochondria and plastids can simultaneously contain the cytosolic aaRS and its corresponding organellar ortholog suggesting that both forms do not share the same organellar function. In addition, a fair number of cytosolic aaRSs have also been found in the nucleus of cells from several species. Hence, these supposedly cytosolic-restricted enzymes have instead the potential to be multi-localized. As expected, in all examples that were studied so far, when the cytosolic aaRS is imported inside an organelle that already contains its bona fide corresponding organellar-restricted aaRSs, the cytosolic form was proven to exert a nonconventional and essential function. Some of these essential functions include regulating homeostasis and protecting against various stresses. It thus becomes critical to assess meticulously the subcellular localization of each of these cytosolic aaRSs to unravel their additional roles. With this objective in mind, we provide here a review on what is currently known about cytosolic aaRSs multi-compartmentalization and we describe all commonly used protocols and procedures for identifying the compartments in which cytosolic aaRSs relocalize in yeast and human cells. [ABSTRACT FROM AUTHOR]

Charcot-Marie-Tooth (CMT) disease is a complex of peripheral nervous system disorders. CMT type 2U (CMT2U) is an autosomal dominant (AD) disease caused by mutations in the MARS gene encoding methionyl-tRNA synthetase; this disease has thus been newly called AD-CMTax- MARS. A few families with mutations in the MARS gene have been reported, without detailed histopathological findings. We describe a 70-year-old woman who had bilateral dysesthesia of the soles since the age of 66 years. Sural nerve biopsy showed a decrease in the density of large myelinated nerve fibers. Increased clusters of regenerating myelinated nerve fibers were noted. Electron microscopic analyses revealed degeneration of unmyelinated nerves. There was no vasculitis or inflammatory cell infiltration. Genetic analysis identified a heterozygous p.P800T mutation, a reported mutation in the MARS gene. We report the detailed histopathological findings in a patient with CMT2U/AD-CMTax- MARS. The findings are similar to those found in CMT2D caused by mutations in the GARS gene, encoding glycyl-tRNA synthetase. [ABSTRACT FROM AUTHOR]

The tRNA identity elements for some amino acids are distinct between the bacterial and archaeal domains. Searching in recent genomic and metagenomic sequence data, we found some candidate phyla radiation (CPR) bacteria with archaeal tRNA identity for Tyr-tRNA and Trp-tRNA synthesis. These bacteria possess genes for tyrosyl-tRNA synthetase (TyrRS) and tryptophanyl-tRNA synthetase (TrpRS) predicted to be derived from DPANN superphylum archaea, while the cognate tRNATyr and tRNATrp genes reveal bacterial or archaeal origins. We identified a trace of domain fusion and swapping in the archaeal-type TyrRS gene of a bacterial lineage, suggesting that CPR bacteria may have used this mechanism to create diverse proteins. Archaeal-type TrpRS of bacteria and a few TrpRS species of DPANN archaea represent a new phylogenetic clade (named TrpRS-A). The TrpRS-A open reading frames (ORFs) are always associated with another ORF (named ORF1) encoding an unknown protein without global sequence identity to any known protein. However, our protein structure prediction identified a putative HIGH-motif and KMSKS-motif as well as many α-helices that are characteristic of class I aminoacyl-tRNA synthetase (aaRS) homologs. These results provide another example of the diversity of molecular components that implement the genetic code and provide a clue to the early evolution of life and the genetic code.

Aminoacyl-tRNA synthetases (aaRSs) catalyze the ligation of amino acids to cognate tRNAs by consuming one molecule of ATP. Magnesium is essential for the enzymes' activity. Certain class II aaRSs, such as lysyl-tRNA synthetase (LysRS) and seryl-tRNA synthetase (SerRS), recognize ATP together with three magnesium ions in the active site. The detailed role of how these magnesium ions facilitate the ATP recognition by the enzyme is unclear. Here, we report analyses of a crystal structure of human LysRS, in which the two enzymatic pockets of the LysRS dimer are in different states. One pocket is vacant of ATP, and the other is in an intermediate state of ATP recognition. Interestingly, only one magnesium ion instead of three is bound in both states. Compared with our previously solved LysRS structures, we proposed the order of binding for the three magnesium ions. These structures also reveal multiple intermediate ATP-bound states during the amino acid activation reaction, providing critical insights into the mechanisms of the magnesium-dependent enzyme activity of class II aaRSs., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors. Published by Elsevier B.V.)

Organellar proteins synthesized in the cytosol are usually selective for only one destination in a cell but some proteins are localized in more than one compartment, for example in both mitochondria and chloroplasts. The mechanism of dual targeting of proteins to mitochondria and chloroplasts is yet poorly understood. Previously, we observed that the dual targeting peptide of threonyl-tRNA synthetase in Arabidopsis thaliana ( At ThrRS-dTP) interacts with the mitochondrial receptor At Tom20 mainly through its N-terminal part. Here we report on the interaction of At ThrRS-dTP with the chloroplastic receptor At Toc34, presenting for the first time the mode of interactions of a dual targeting peptide with both Tom20 and Toc34. By NMR spectroscopy we investigated changes in 15 N HSQC spectra of At ThrRS-dTP as a function of At Toc34 concentration. Line broadening shows that the interaction with At Toc34 involves residues along the entire sequence, which is not the case for At Tom20. The N-terminal φχχφφ motif, which plays an important role in At Tom20 recognition, shows no specificity for At Toc34. These results are supported by import competition studies into both mitochondria and chloroplasts, in which the effect of peptides corresponding to different segments of At ThrRS-dTP on in vitro import of organelle specific proteins was examined. This demonstrates that the N-terminal A2-Y29 segment of At ThrRS-dTP is essential for import into both organelles, while the C-terminal L30-P60 part is important for chloroplastic import efficiency. In conclusion, we have demonstrated that the recognition of the dual targeting peptide of At Thr-tRNA synthetase is different for the mitochondrial and chloroplastic receptors. [ABSTRACT FROM AUTHOR]

INTRODUCTION: Acne vulgaris is one of the most common skin conditions in children and adolescents. The presentation, differential diagnosis, and association of acne with systemic pathology differs by age of presentation. Current acknowledged guidelines for the diagnosis and management of pediatric acne are lacking, and there are variations in management across the spectrum of primary and specialty care. The American Acne and Rosacea Society convened a panel of pediatric dermatologists, pediatricians, and dermatologists with expertise in acne to develop recommendations for the management of pediatric acne and evidence-based treatment algorithms. METHODS: Ten major topic areas in the diagnosis and treatment of pediatric acne were identified. A thorough literature search was performed and articles identified, reviewed, and assessed for evidence grading. Each topic area was assigned to 2 expert reviewers who developed and presented summaries and recommendations for critique and editing. Furthermore, the Strength of Recommendation Taxonomy, including ratings for the strength of recommendation for a body of evidence, was used throughout for the consensus recommendations for the evaluation and management of pediatric acne. Practical evidence-based treatment algorithms also were developed. RESULTS: Recommendations were put forth regarding the classification, diagnosis, evaluation, and management of pediatric acne, based on age and pubertal status. Treatment considerations include the use of over-the-counter products, topical benzoyl peroxide, topical retinoids, topical antibiotics, oral antibiotics, hormonal therapy, and isotretinoin. Simplified treatment algorithms and recommendations are presented in detail for adolescent, preadolescent, infantile, and neonatal acne. Other considerations, including psychosocial effects of acne, adherence to treatment regimens, and the role of diet and acne, also are discussed. CONCLUSIONS: These expert recommendations by the American Acne and Rosacea Society as reviewed and endorsed by the American Academy of Pediatrics constitute the first detailed, evidence-based clinical guidelines for the management of pediatric acne including issues of special concern when treating pediatric patients. Pediatrics 2013;131: S163-S186 [ABSTRACT FROM AUTHOR]

Cell-free biology is increasingly utilized for engineering biological systems, incorporating novel functionality, and circumventing many of the complications associated with cells. The central dogma describes the information flow in biology consisting of transcription and translation steps to decode genetic information. Aminoacyl tRNA synthetases (AARSs) and tRNAs are key components involved in translation and thus protein synthesis. This review provides information on AARSs and tRNA biochemistry, their role in the translation process, summarizes progress in cell-free engineering of tRNAs and AARSs, and discusses prospects and challenges lying ahead in cell-free engineering., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Ganesh and Maerkl.)

Abstract: The in situ activity of the enzymes aminoacyl-tRNA synthetases (AARS) and the growth rates of naupliar stages of the planktonic marine copepod Paracartia grani were measured in the laboratory under different temperature and food concentrations. We assessed the effect of these parameters on growth and protein synthesis rates of P. grani nauplii. Growth and protein synthesis rates of P. grani nauplii depended on temperature and food concentration. AARS activity is valid as an index of somatic growth for P. grani nauplii when growth is not limited by food availability. However, the relationship between protein-specific AARS activity and nauplii growth varied according to food availability levels. The degradation of proteins during starvation and/or the ß-oxidation of fatty acids affected the relationship between specific AARS activity and growth rates. The results presented here add to previous studies showing that the AARS activity is a useful tool for estimating somatic growth of this and other key copepod species. Nevertheless, further research is required to elucidate the validity of AARS activity as a universal proxy for growth. [Copyright &y& Elsevier]

Purpose: Atlantoaxial rotatory fixation and atlantoaxial rotatory subluxation are the most frequent manifestations of atlantoaxial rotatory dislocation (AARD) in pediatric population and are often treated conservatively. The objective of this study is to correlate the changes highlighted on MRI T2-weighted and STIR sequences with the duration of conservative treatment. Methods: We analyzed nine consecutive patients treated surgically between 1 Jan 2006 and 1 Jan 2010 at the Policlinico Umberto I of Rome. All patients underwent cervical X-ray, computed tomography and magnetic resonance imaging (MRI) (T1 and T2-weighted, STIR, angio MRI). All patients were treated with bed rest, muscle relaxants and cervical collar, and radiological follow-up with MRI and cervical X-ray was performed. Results: According to Fielding's classification, we observed seven patients with a type 1 subluxation and two patients with a type II subluxation. In type 1, STIR and T2 sequences showed a hyperintensity in the alar and capsular ligaments and in the posterior ligamentous system, with integrity of the transverse ligament (LTA). In type 2, the hyperintensity also involved the LTA. During the follow-up, MRI showed a progressive reduction until the disappearance of the hyperintensity described, which was followed by a break with orthotic immobilization. Conclusions: MRI with STIR sequences appears to be useful in addressing the duration of conservative treatment in AARD. [ABSTRACT FROM AUTHOR]

Abstract: Despite the abundance of the marine copepod genus Oithona, little is known about its ecology and metabolism, especially regarding its early developmental stages. In this work, we combined two biochemical indices, already used in calanoid copepods, to estimate growth and fitness of Oithona davisae nauplii and copepodites: i) the specific aminoacyl-tRNA synthetases (spAARS) activity (proxy of protein synthesis rate) and ii) the RNA/DNA ratio (indicative of overall metabolic activity). We show here that the two analyses can be performed on the same organisms (samples), thus providing comparable and complementary information about the nauplii physiology. Our experiments provide a first insight into the variability of these parameters on O. davisae early developmental stages, showing that RNA/DNA ratio was more sensitive to starvation than the spAARS activity. A common relationship for nauplii and copepodites was observed between spAARS activity and somatic growth rates; however, RNA/DNA ratio relationships with both somatic growth rates and spAARS activity differed between the naupliar and copepodite stages. The study presented here contributes to the advancement of the study of small copepod nauplii physiology. [Copyright &y& Elsevier]

Adhesive applied roofing systems (AARS), a new generation of built-up roofs, are gaining popularity in North American low slope application. AARS uses no fasteners and all components (e.g., deck, vapour barrier, insulation board, and membrane) are integrated by the use of adhesives. As there are no metal fasteners, AARS can offer an advantage of reduction in condensation and thermal bridges for the roof assemblies. Even though, AARS have been in use, there have been no standard that exists to quantify its wind uplift performances. An industries-university- Canadian government collaborative research project, "Development of Wind Uplift Standard for Adhesive Applied Low Slope Roofing System," has been initiated with three major tasks: Experimental investigation, formulation of a numerical model and development of wind design guide and standards. This paper documents a standardized small scale laboratory test method for the quantification of uplift resistance subject to tensile loading. As part of Task 1 of the project, this systematic investigation focuses on three key parameters: Loading rate, specimen size and end condition. The investigations were completed by constructing over 400 specimens. Both the maximum uplift resistance and the consistence in the failure plane are equally considered during the test method standardization. The data from this small scale testing can facilitate roofing industries to optimize the material combinations such that the uplift resistance data can be used as an indicator before performing a full-scale wind uplift testing. [ABSTRACT FROM AUTHOR]

Oxidative stress arises from excessive reactive oxygen species (ROS) and affects organisms of all three domains of life. Here we present a previously unknown pathway through which ROS may impact faithful protein synthesis. Aminoacyl-tRNA synthetases are key enzymes in the translation of the genetic code; they attach the correct amino acid to each tRNA species and hydrolyze an incorrectly attached amino acid in a process called editing. We show both in vitro and in vivo in Escherichia coil that ROS reduced the overall translational fidelity by impairing the editing activity of threonyl-tRNA synthetase. Hydrogen peroxide oxidized cysteine182 residue critical for editing, leading to Ser-tRNAThr formation and protein mistranslation that impaired growth of Escherichia coli. The presence of major heat shock proteases was required to allow cell growth in medium containing serine and hydrogen peroxide; this suggests that the mistranslated proteins were misfolded. [ABSTRACT FROM AUTHOR]

The vertical distribution (0–550 m) of zooplankton biomass, and indices of respiration (electron transfer system [ETS]) and structural growth (aminoacyl-tRNA synthetases activity [AARS]), were studied in waters off the Antarctic Peninsula during the austral summer of 2000. The dominant species were the copepod Metridia gerlachei and the euphausiid Euphausia superba. We observed a vertical krill/copepod substitution in the water column. The zooplankton biomass in the layer at a depth of 200–500 m was of the same magnitude as the biomass in the layer at a depth of 0–200 m, indicating that biomass in the mesopelagic zone is an important fraction of the total zooplankton in Antarctic waters. The metabolic rates of the zooplankton community were sustained by less than 0.5% of the primary production in the area, suggesting that microplankton or small copepods are the main food source. Neither food availability nor predation seemed to control mesozooplankton biomass. The wide time lag between the abundance peak of the dominant copepod ( M. gerlachei) and the phytoplankton bloom is suggested to be the main explanation for the low summer zooplankton biomass observed in these waters. [ABSTRACT FROM AUTHOR]

Abstract: Surface distribution (0–100m) of zooplankton biomass and specific aminoacyl-tRNA synthetases (AARS) activity, as a proxy of structural growth, were assessed during winter 2002 and spring 2004 in the Labrador Sea. Two fronts formed by strong boundary currents, several anticyclonic eddies and a cyclonic eddy were studied. The spatial contrasts observed in seawater temperature, salinity and fluorescence, associated with those mesoscale structures, affected the distributions of both zooplankton biomass and specific AARS activity, particularly those of the smaller individuals. Production rates of large organisms (200–1000μm) were significantly related to microzooplankton biomass (63–200μm), suggesting a cascade effect from hydrography through microzooplankton to large zooplankton. Water masses defined the biomass distribution of the three dominant species: Calanus glacialis was restricted to cold waters on the shelves while Calanus hyperboreus and Calanus finmarchicus were widespread from Canada to Greenland. Zooplankton production was up to ten-fold higher inside anticyclonic eddies than in the surrounding waters. The recent warming tendency observed in the Labrador Sea will likely generate weaker convection and less energetic mesoscale eddies. This may lead to a decrease in zooplankton growth and production in the Labrador basin. [Copyright &y& Elsevier]