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1.
Structure ; 2024 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-38959899

RESUMO

LoaP is a member of the universal NusG protein family. Previously, we reported that unlike other characterized homologs, LoaP binds RNA sequence-specifically, recognizing a stem-loop in the 5'-untranslated region of operons it regulates. To elucidate how this NusG homolog acquired this ability, we now determined the co-crystal structure of Thermoanaerobacter pseudethanolicus LoaP bound to its cognate 26-nucleotide dfn RNA element. Our structure reveals that the LoaP C-terminal KOW domain recognizes the helical portion of the RNA by docking into a broadened major groove, while a protruding ß-hairpin of the N-terminal NusG-like domain binds the UNCG tetraloop capping the stem-loop. Major-groove RNA recognition is unusual and is made possible by conserved features of the dfn hairpin. Superposition with structures of other NusG proteins implies that LoaP can bind concurrently to the dfn RNA and the transcription elongation complex, suggesting a new level of co-transcriptional regulation by proteins of this conserved family.

2.
Int J Tuberc Lung Dis ; 28(5): 217-224, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38659144

RESUMO

BACKGROUNDDespite the high morbidity and mortality globally, standard microbiologic diagnosis for TB requires laboratory infrastructure inaccessible in many resource-limited areas and may be insufficient for identifying extrapulmonary disease. Point-of-care (POC) ultrasound facilitates visualization of extrapulmonary manifestations, permitting laboratory-independent diagnosis, but its diagnostic utility remains unclear.METHODSWe conducted a systematic review of five online databases for studies reporting ultrasound findings among cases with and without extrapulmonary TB (EPTB). A minimum of two authors independently screened and reviewed each article, and extracted data elements of interest. We conducted a series of univariate meta-analyses using a random-effects model to calculate the pooled effect estimate and 95% confidence interval (CI) for each outcome: sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV).RESULTSOf 279 articles identified, 6 were included. There were 699 cases of EPTB among 1,633 participants. The pooled sensitivity estimate was 0.72 (95% CI 0.57-0.88). The pooled specificity estimate was 0.77 (95% CI 0.63-0.90). The pooled PPV and NPV estimates were respectively 0.67 (95% CI 0.47-0.87) and 0.85 (95% CI 0.77-0.93).CONCLUSIONPOC ultrasound showed modest test characteristics for diagnosing EPTB, which may constitute an improvement over some currently available diagnostics..


Assuntos
Sistemas Automatizados de Assistência Junto ao Leito , Valor Preditivo dos Testes , Sensibilidade e Especificidade , Tuberculose , Ultrassonografia , Humanos , Tuberculose/diagnóstico por imagem , Tuberculose/diagnóstico
3.
Body Image ; 49: 101702, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38492459

RESUMO

The study examined whether a 10-minute mindfulness meditation intervention could ameliorate effects of exposure to social media thinspiration and fitspiration images on women's self-esteem, mood, and body appreciation. A total of 162 women aged 18-42 years (M = 25.94, SD = 4.38) completed an online experiment which involved viewing thinspiration and fitspiration images before random allocation to either a brief, ten-minute mindfulness meditation audio intervention or a ten-minute control audio about jujitsu. Participants completed self-reported measures of self-esteem, positive and negative mood, and body appreciation at baseline (Time 1), post-exposure to idealised social media images (Time 2), and immediately post-intervention (Time 3). Mixed, repeated-measures ANOVAs showed that scores were lower for body appreciation, self-esteem, and positive mood, and higher for negative mood, in both groups after exposure to idealised imagery. However, a brief mindfulness intervention ameliorated the negative effects of social media exposure. Specifically, self-esteem, body appreciation, and mood were higher in the mindfulness meditation group at Time 3, compared to the control group. Future interventions should explore the utility of mindfulness practices to provide long term buffering effects against such social media content, as well as targeting the idealisation of female physiques portrayed in thinspiration and fitspiration content.


Assuntos
Afeto , Imagem Corporal , Meditação , Atenção Plena , Autoimagem , Mídias Sociais , Humanos , Feminino , Atenção Plena/métodos , Adulto Jovem , Meditação/psicologia , Meditação/métodos , Adulto , Adolescente , Imagem Corporal/psicologia
4.
Anaesthesia ; 2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38536762

RESUMO

Physical disability is a common component of post-intensive care syndrome, but the importance of musculoskeletal health in this population is currently unknown. We aimed to determine the musculoskeletal health state of intensive care unit survivors and assess its relationship with health-related quality of life; employment; and psychological and physical function. We conducted a multicentre prospective cohort study of adults admitted to intensive care for > 48 h without musculoskeletal trauma or neurological insult. Patients were followed up 6 months after admission where musculoskeletal health state was measured using the validated Musculoskeletal Health Questionnaire score. Of the 254 participants, 150 (59%) had a musculoskeletal problem and only 60 (24%) had received physiotherapy after discharge. Functional Comorbidity Index, Clinical Frailty Scale, duration of intensive care unit stay and prone positioning were all independently associated with worse musculoskeletal health. Musculoskeletal health state moderately correlated with quality of life, rs = 0.499 (95%CI 0.392-0.589); anxiety, rs = -0.433 (95%CI -0.538 to -0.315); and depression, rs = -0.537 (95%CI -0.631 to -0.434) (all p < 0.001). Patients with a musculoskeletal problem were less physically active than those without a problem (median (IQR [range]) number of 30 min physical activity sessions per week 1 (0-3.25 [0-7]) vs. 4 (1-7 [0-7]), p < 0.001, respectively). This study found that musculoskeletal health problems were common after intensive care unit stay. However, we observed that < 25% of patients received physical rehabilitation after discharge home. Our work has identified potential high-risk groups to target in future interventional studies.

5.
J Homosex ; : 1-26, 2023 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-38117910

RESUMO

Sexual and gender minority (SGM) youth are at risk for adverse health outcomes because of stigma and discrimination exposure. Individuals' beliefs about the biological origin of SGM identity are linked to their negative attitudes and biases against SGM populations, which can also apply to pediatric healthcare providers. The current study outlines validation of the Etiology Beliefs about Sexual and Gender Minority Youth (EB-SGM) scale, a 12-item measure designed to assess adults' beliefs about youths' biological versus environmental SGM etiology. College students (N = 285; study 1), community adults (N = 258; study 2), and pediatric providers (N = 104; study 3) completed the EB-SGM and other self-report measures. Exploratory factor analysis (EFA) in study 1 revealed a three-factor structure: beliefs about gender nonconforming behavior, beliefs about gender identity, and beliefs about sexual attraction/behavior. Confirmatory factor analysis (CFA) in study 2 suggested a bi-factor structure, which was replicated in study 3. The EB-SGM demonstrated adequate concurrent and discriminant validity. We also examined bivariate correlations between etiology beliefs and sociodemographic characteristics across samples. Findings indicate that EB-SGM is a psychometrically sound instrument to measure adults' etiology beliefs. The EB-SGM has the potential to be used as a screening measure to enhance pediatric healthcare providers' SGM training.

6.
Dalton Trans ; 52(33): 11419-11426, 2023 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-37538026

RESUMO

Oligo- and polyazulenes are attractive π-conjugated building blocks in designing advanced functional materials. Herein, we demonstrate that anchoring one or both isocyanide termini of the redox non-innocent 2,2'-diisocyano-6,6'-biazulenic π-linker (1) to the redox-active [Cr(CO)5] moiety provided a convenient intramolecular redox reference for unambiguously establishing that the 6,6'-biazulenic scaffold undergoes a reversible one-step 2e- reduction governed by reduction potential compression/inversion. Treatment of bis(η6-naphthalene)chromium(0) with six equiv. of 2-isocyano-1,1',3,3'-tetraethoxycarbonyl-6,6'-biazulene (6) or [(OC)5Cr(η1-2,2'-diisocyano-1,1',3,3'-tetraethoxycarbonyl-6,6'-biazulene)] (11) afforded homoleptic Cr(0) complexes 13 and 14 with a 12e- (per molecule) ligand-based reduction capacity at mild E1/2 of -1.29 V and -1.15 V vs. Cp2Fe0/+, respectively. The overall reversible redox capacity varies from 15e- for the mononuclear complex 13 to 21e- for the heptanuclear complex 14. The latter "nanocomplex" has a diameter of ca. 5 nm and features seven Cr(0) centers interlinked with six 2,2'-diisocyano-6,6'-biazulenic bridges. The X-ray structure of [(OC)5Cr(2-isocyano-1,1',3,3'-tetraethoxycarbonyl-6,6'-biazulene)] (7) indicated a 43.5° interplanar angle between the two azulenic moieties. Self-assembly of 11 on a Au(111) substrate afforded an organometallic monolayer film of 11 featuring approximately upright orientation of the 2,2'-diisocyano-6,6'-biazulenic linkers, as evidenced by ellipsometric measurements and the RAIR signature of the C4v-symmetric [(-NC)Cr(CO)5] infrared reporter within 11. Remarkably, comparing the FTIR spectrum of 11 in solution with the RAIR spectrum of 11 adsorbed on Au(111) suggested electronic coupling at a ca. 2 nm distance between the Cr(0) and Au atoms linked by the 2,2'-diisocyano-6,6'-biazulene bridge.

7.
Nucleic Acids Res ; 51(18): 9804-9820, 2023 10 13.
Artigo em Inglês | MEDLINE | ID: mdl-37650646

RESUMO

All cells employ a combination of endo- and exoribonucleases to degrade long RNA polymers to fragments 2-5 nucleotides in length. These short RNA fragments are processed to monoribonucleotides by nanoRNases. Genetic depletion of nanoRNases has been shown to increase abundance of short RNAs. This deleteriously affects viability, virulence, and fitness, indicating that short RNAs are a metabolic burden. Previously, we provided evidence that NrnA is the housekeeping nanoRNase for Bacillus subtilis. Herein, we investigate the biological and biochemical functions of the evolutionarily related protein, B. subtilis NrnB (NrnBBs). These experiments show that NrnB is surprisingly different from NrnA. While NrnA acts at the 5' terminus of RNA substrates, NrnB acts at the 3' terminus. Additionally, NrnA is expressed constitutively under standard growth conditions, yet NrnB is selectively expressed during endospore formation. Furthermore, NrnA processes only short RNAs, while NrnB unexpectedly processes both short RNAs and longer RNAs. Indeed, inducible expression of NrnB can even complement the loss of the known global 3'-5' exoribonucleases, indicating that it acts as a general exonuclease. Together, these data demonstrate that NrnB proteins, which are widely found in Firmicutes, Epsilonproteobacteria and Archaea, are fundamentally different than NrnA proteins and may be used for specialized purposes.


Assuntos
Bacillus subtilis , Proteínas de Bactérias , Exorribonucleases , Bacillus subtilis/genética , Bacillus subtilis/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Exorribonucleases/genética , Exorribonucleases/metabolismo , Fosfodiesterase I , RNA/metabolismo
8.
Proc Natl Acad Sci U S A ; 120(21): e2217189120, 2023 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-37186841

RESUMO

Protonation reactions involving organometallic complexes are ubiquitous in redox chemistry and often result in the generation of reactive metal hydrides. However, some organometallic species supported by η5-pentamethylcyclopentadienyl (Cp*) ligands have recently been shown to undergo ligand-centered protonation by direct proton transfer from acids or tautomerization of metal hydrides, resulting in the generation of complexes bearing the uncommon η4-pentamethylcyclopentadiene (Cp*H) ligand. Here, time-resolved pulse radiolysis (PR) and stopped-flow spectroscopic studies have been applied to examine the kinetics and atomistic details involved in the elementary electron- and proton-transfer steps leading to complexes ligated by Cp*H, using Cp*Rh(bpy) as a molecular model (where bpy is 2,2'-bipyridyl). Stopped-flow measurements coupled with infrared and UV-visible detection reveal that the sole product of initial protonation of Cp*Rh(bpy) is [Cp*Rh(H)(bpy)]+, an elusive hydride complex that has been spectroscopically and kinetically characterized here. Tautomerization of the hydride leads to the clean formation of [(Cp*H)Rh(bpy)]+. Variable-temperature and isotopic labeling experiments further confirm this assignment, providing experimental activation parameters and mechanistic insight into metal-mediated hydride-to-proton tautomerism. Spectroscopic monitoring of the second proton transfer event reveals that both the hydride and related Cp*H complex can be involved in further reactivity, showing that [(Cp*H)Rh] is not necessarily an off-cycle intermediate, but, instead, depending on the strength of the acid used to drive catalysis, an active participant in hydrogen evolution. Identification of the mechanistic roles of the protonated intermediates in the catalysis studied here could inform design of optimized catalytic systems supported by noninnocent cyclopentadienyl-type ligands.

10.
Behav Sci Law ; 41(5): 262-279, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36960891

RESUMO

This is a descriptive study of 21 cases of serial sexual murder by children and adolescents spanning nearly the past century and a half. No earlier cases worldwide were identified. Each of these youth committed two or more sexual homicides prior to age 18. Their psychopathological, psychosocial, crime scene behaviors, and offender-victim relationship characteristics are presented. Additionally, the role of sexual sadism and its measurement using the SADSEX-SH rating scale is addressed. Nearly all of the sample had conduct disorder, a paraphilic disorder, and sadistic fantasies, and two-thirds had sexual sadism disorder. Family dysfunction, serious school problems, and average or above IQ levels were typical. Their modus operandi generally reflected predatory behavior and direct contact methods of killing were most common. Two case reports are provided to illustrate the breadth and complexity of these offenders. Juvenile Serial Sexual Homicide is an extremely rare but persistent phenomenon. Prognostic implications and future research directions are discussed.


Assuntos
Vítimas de Crime , Transtornos Parafílicos , Delitos Sexuais , Criança , Adolescente , Humanos , Sadismo/psicologia , Delitos Sexuais/psicologia , Transtornos Parafílicos/psicologia , Comportamento Sexual , Homicídio/psicologia
11.
Artigo em Inglês | MEDLINE | ID: mdl-36901292

RESUMO

Limited information is available on the prevalence and nature of sexual offending in Hong Kong. This cross-sectional study seeks to explore the role of risky sexual behavior (RSB) and paraphilic interests in self-reported sexual offending behavior (i.e., nonpenetrative-only, penetrative-only, and nonpenetrative-plus-penetrative sexual assault) in a community sample of young adults in Hong Kong. Using a large sample (N = 1885) of university students, the lifetime prevalence of self-reported sexual offending was 18% (n = 342; 23% males (n = 166), 15% females (n = 176)). Based on the study subsample of 342 participants who self-reported sexual offending (aged 18-35), the findings indicated that males reported significantly higher levels of general, penetrative-only, nonpenetrative-plus-penetrative sexual assault; and paraphilic interest in voyeurism, frotteurism, biastophilia, scatophilia, and hebephilia than females; while females reported a significantly higher level of transvestic fetishism than males. No significant difference was found in RSB between males and females. Logistic regressions found that the participants who possessed a higher level of RSB, particularly penetrative behaviors, and paraphilic interest in voyeurism and zoophilia were less likely to engage in a nonpenetrative-only sexual offense. Conversely, the participants who possessed higher levels of RSB, especially penetrative behaviors, and paraphilic interest in exhibitionism and zoophilia, were more likely to engage in nonpenetrative-plus-penetrative sexual assault. The implications for practice in areas such as public education and offender rehabilitation are discussed.


Assuntos
Transtornos Parafílicos , Delitos Sexuais , Masculino , Feminino , Humanos , Adulto Jovem , Hong Kong , Estudos Transversais , Comportamento Sexual , Transtornos Parafílicos/epidemiologia
12.
Microbiol Spectr ; : e0335722, 2023 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-36786617

RESUMO

The shell proteins that comprise bacterial microcompartments (BMCs) can self-assemble into an array of superstructures such as nanotubes, flat sheets, and icosahedra. The physical characterization of BMCs and these superstructures typically relies on electron microscopy, which decouples samples from their solution context. We hypothesize that an investigation of fluorescently tagged BMCs and shell protein superstructures in vitro using high-resolution confocal microscopy will lead to new insights into the solution behavior of these entities. We find that confocal imaging is able to capture nanotubes and sheets previously reported by transmission electron microscopy (TEM). Using a combination of fluorescent tags, we present qualitative evidence that these structures intermix with one another in a hetero- and homotypic fashion. Complete BMCs are also able to accomplish intermixing as evidenced by colocalization data. Finally, a simple colocalization experiment suggests that fluorescently modified encapsulation peptides (EPs) may prefer certain shell protein binding partners. Together, these data demonstrate that high-resolution confocal microscopy is a powerful tool for investigating microcompartment-related structures in vitro, particularly for colocalization analyses. These results also support the notion that BMCs may intermix protein components, presumably from the outer shell. IMPORTANCE Microcompartments are large, organelle-like structures that help bacteria catabolize targeted metabolites while also protecting the cytosol against highly reactive metabolic intermediates. Their protein shell self-assembles into a polyhedral structure of approximately 100 to 200 nm in diameter. Inside the shell are thousands of copies of cargo enzymes, which are responsible for a specific metabolic pathway. While different approaches have revealed high-resolution structures of individual microcompartment proteins, it is less clear how these factors self-assemble to form the full native structure. In this study, we show that laser scanning confocal microscopy can be used to study microcompartment proteins. We find that this approach allows researchers to investigate the interactions and potential exchange of shell protein subunits in solution. From this, we conclude that confocal microscopy offers advantages for studying the in vitro structures of other microcompartments as well as carboxysomes and other bacterial organelles.

13.
Nucleic Acids Res ; 50(21): 12369-12388, 2022 11 28.
Artigo em Inglês | MEDLINE | ID: mdl-36478094

RESUMO

Bacterial RNases process RNAs until only short oligomers (2-5 nucleotides) remain, which are then processed by one or more specialized enzymes until only nucleoside monophosphates remain. Oligoribonuclease (Orn) is an essential enzyme that acts in this capacity. However, many bacteria do not encode for Orn and instead encode for NanoRNase A (NrnA). Yet, the catalytic mechanism, cellular roles and physiologically relevant substrates have not been fully resolved for NrnA proteins. We herein utilized a common set of reaction assays to directly compare substrate preferences exhibited by NrnA-like proteins from Bacillus subtilis, Enterococcus faecalis, Streptococcus pyogenes and Mycobacterium tuberculosis. While the M. tuberculosis protein specifically cleaved cyclic di-adenosine monophosphate, the B. subtilis, E. faecalis and S. pyogenes NrnA-like proteins uniformly exhibited striking preference for short RNAs between 2-4 nucleotides in length, all of which were processed from their 5' terminus. Correspondingly, deletion of B. subtilis nrnA led to accumulation of RNAs between 2 and 4 nucleotides in length in cellular extracts. Together, these data suggest that many Firmicutes NrnA-like proteins are likely to resemble B. subtilis NrnA to act as a housekeeping enzyme for processing of RNAs between 2 and 4 nucleotides in length.


Assuntos
Exonucleases , Firmicutes , RNA , Proteínas de Bactérias/metabolismo , Exonucleases/química , Nucleotídeos , RNA/metabolismo , Firmicutes/química , Firmicutes/classificação , Firmicutes/enzimologia
14.
J Helminthol ; 96: e81, 2022 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-36321434

RESUMO

A parasitological survey of terrestrial slugs and snails was conducted at popular dog walking locations across the city of Nottingham, with the intensions of finding gastropods infected with parasites of medical (or veterinary) importance such as lungworm (metastrongyloid nematodes) and trematodes. A total of 800 gastropods were collected from 16 sites over a 225 km2 area. The extracted nematodes and trematodes were identified by molecular barcoding. Of the 800 gastropods collected, 227 were infected (172 had nematode infections, 37 had trematode infections and 18 had both nematode and trematode infections). Of the nematode infected gastropods genotyped, seven species were identified, Agfa flexilis, Angiostoma gandavense, Angiostoma margaretae, Cosmocerca longicauda, Phasmarhabditis hermaphrodita, Phasmarhabditis neopapillosa and an unknown Cosmocercidae species. Of the trematode infected gastropods genotyped, four species were identified, Brachylaima arcuate, Brachylaima fuscata, Brachylaima mesostoma and an unknown Plagiorchioidea species. No lungworm species were found within the city of Nottingham. To our knowledge, this study represents the first survey of gastropod-associated nematodes and trematodes in the East midlands of the United Kingdom.


Assuntos
Gastrópodes , Nematoides , Trematódeos , Animais , Cães , Nematoides/classificação , Nematoides/genética , Nematoides/isolamento & purificação , Rhabditoidea/genética , Rhabditoidea/isolamento & purificação , Caramujos/parasitologia , Trematódeos/classificação , Trematódeos/genética , Trematódeos/isolamento & purificação , Infecções por Trematódeos/epidemiologia , Infecções por Trematódeos/parasitologia , Infecções por Trematódeos/veterinária , Inglaterra/epidemiologia , Código de Barras de DNA Taxonômico , Infecções por Nematoides/epidemiologia , Infecções por Nematoides/parasitologia , Infecções por Nematoides/veterinária , Genótipo , Cidades/estatística & dados numéricos , Caminhada , Doenças do Cão/parasitologia , Gastrópodes/parasitologia
15.
Sci Rep ; 12(1): 15439, 2022 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-36104420

RESUMO

Congenital sensorineural deafness (CSD) has been reported to affect up to 30% of Dalmatian dogs world-wide and while unilaterally deaf dogs can live a close to normal life, dogs suffering bilateral deafness are frequently euthanized. Extreme-white coat patterning as encoded by the gene Melanocyte Inducing Transcription Factor (MITF) has long been postulated as the major risk factor for CSD in the Dalmatian breed. While attempts to identify causative risk variants associated with CSD have been numerous, no genome-wide association study has positively identified MITF as a risk locus for either bilateral or unilateral deafness in the Dalmatian breed to date. In this study, we identified an association with CSD on CFA20 in the vicinity of MITF within Australian Dalmatian dogs. Although not genome-wide significant, the association signal was validated by reanalysing publicly available data and merging the wider data resource with the local data to improve statistical power. The merged data, representing three major global populations of Dalmatian dogs, enabled us to identify a single, well-defined genome-wide significant risk haplotype for CSD. The haplotype was formed by three genome-wide significant associated markers (BICF2G630233852T>C, BICF2G630233861T>C, BICF2G630233888G>A) on CFA20 with 62% of bilaterally deaf dogs homozygous for the risk haplotype (CCA), while 30% of bilaterally deaf and 45% of hearing dogs carried one copy of the risk haplotype. Animals homozygous or heterozygous for the low-risk haplotype were less likely to be unilaterally deaf. While the association between the risk haplotype and deafness is incomplete, animals homozygous for the risk haplotype were 10-times more likely to be bilaterally deaf. Although the underlying causative variants are yet to be discovered, results from this study can now assist with reducing deafness in Dalmatian dogs.


Assuntos
Surdez , Doenças do Cão , Perda Auditiva Neurossensorial , Animais , Austrália , Surdez/genética , Surdez/veterinária , Doenças do Cão/genética , Cães , Haplótipos , Perda Auditiva Neurossensorial/congênito , Perda Auditiva Neurossensorial/genética , Perda Auditiva Neurossensorial/veterinária
16.
FEMS Microbiol Rev ; 46(6)2022 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-36026528

RESUMO

Diribonucleotides arise from two sources: turnover of RNA transcripts (rRNA, tRNA, mRNA, and others) and linearization of cyclic-di-nucleotide signaling molecules. In both cases, there appears to be a requirement for a dedicated set of enzymes that will cleave these diribonucleotides into mononucleotides. The first enzyme discovered to mediate this activity is oligoribonuclease (Orn) from Escherichia coli. In addition to being the enzyme that cleaves dinucleotides and potentially other short oligoribonucleotides, Orn is also the only known exoribonuclease enzyme that is essential for E. coli, suggesting that removal of the shortest RNAs is an essential cellular function. Organisms naturally lacking the orn gene encode other nanoRNases (nrn) that can complement the conditional E. coli orn mutant. This review covers the history and recent advances in our understanding of these enzymes and their substrates. In particular, we focus on (i) the sources of diribonucleotides; (ii) the discovery of exoribonucleases; (iii) the structural features of Orn, NrnA/NrnB, and NrnC; (iv) the enzymatic activity of these enzymes against diribonucleotides versus other substrates; (v) the known physiological consequences of accumulation of linear dinucleotides; and (vi) outstanding biological questions for diribonucleotides and diribonucleases.


Assuntos
Endorribonucleases , Escherichia coli , Escherichia coli/genética , Transdução de Sinais
17.
Health Phys ; 122(6): 705-706, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35486927
18.
Structure ; 30(4): 537-550.e5, 2022 04 07.
Artigo em Inglês | MEDLINE | ID: mdl-35216657

RESUMO

Bacterial microcompartments (BMCs) are widespread in bacteria and are used for a variety of metabolic purposes, including catabolism of host metabolites. A suite of proteins self-assembles into the shell and cargo layers of BMCs. However, the native assembly state of these large complexes remains to be elucidated. Herein, chemical probes were used to observe structural features of a native BMC. While the exterior could be demarcated with fluorophores, the interior was unexpectedly permeable, suggesting that the shell layer may be more dynamic than previously thought. This allowed access to cross-linking chemical probes, which were analyzed to uncover the protein interactome. These cross-links revealed a complex multivalent network among cargo proteins that contained encapsulation peptides and demonstrated that the shell layer follows discrete rules in its assembly. These results are consistent overall with a model in which biomolecular condensation drives interactions of cargo proteins before envelopment by shell layer proteins.


Assuntos
Proteínas de Bactérias , Organelas , Bactérias/metabolismo , Proteínas de Bactérias/química , Organelas/metabolismo , Peptídeos/metabolismo
19.
J Youth Adolesc ; 51(4): 724-745, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35122568

RESUMO

Adolescent involvement in risky behavior is ubiquitous and normative. Equally pervasive is the rapid decline in risky behavior during the transition to adulthood. Yet, for many, risky behavior results in arrest. Whereas prior research finds that arrest is associated with an increased risk of experiencing a host of detrimental outcomes, less understood is the impact of an arrest on the developmental course of offending compared to what it would have looked like if no arrest had occurred-the counterfactual. This study examines the developmental implications of an arrest early in the life course. The sample (N = 1293) was 37% female, 42% non-white, with a mean age of 13.00 years (SD = 0.82, range = 12-14) at baseline and followed annually for 15 years. Analyses combine propensity score matching and multilevel modeling techniques to estimate the impact of early arrest (i.e., 14 or younger) on the development of offending from adolescence into adulthood. The results indicate that early arrest alters the developmental course of offending in two primary ways. First, early arrest heightens involvement, frequency, and severity of offending throughout adolescence and into early young adulthood even after controlling for subsequent arrests. The detrimental influence of early arrest on the developmental course of offending is found regardless of gender or race/ethnicity. Second, even among youth with an early arrest, offending wanes over time with self-reported offending among all youth nearly absent by the mid- to late-twenties. The findings advance understanding of the developmental implications of early arrest beyond typical and expected offending.


Assuntos
Criminosos , Adolescente , Adulto , Criança , Etnicidade , Feminino , Humanos , Estudos Longitudinais , Masculino , Assunção de Riscos , Autorrelato , Adulto Jovem
20.
Chemistry ; 28(9): e202103970, 2022 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-35006643

RESUMO

Ligands based upon the 4,5-diazafluorene core are an important class of emerging ligands in organometallic chemistry, but the structure and electronic properties of these ligands have received less attention than they deserve. Here, we show that 9,9'-dimethyl-4,5-diazafluorene (Me2 daf) can stabilize low-valent complexes through charge delocalization into its conjugated π-system. Using a new platform of [Cp*Rh] complexes with three accessible formal oxidation states (+III, +II, and +I), we show that the methylation in Me2 daf is protective, blocking Brønsted acid-base chemistry commonly encountered with other daf-based ligands. Electronic absorption spectroscopy and single-crystal X-ray diffraction analysis of a family of eleven new compounds, including the unusual Cp*Rh(Me2 daf), reveal features consistent with charge delocalization driven by π-backbonding into the LUMO of Me2 daf, reminiscent of behavior displayed by the workhorse 2,2'-bipyridyl ligand. Taken together with spectrochemical data demonstrating clean conversion between oxidation states, our findings show that 9,9'-dialkylated daf-type ligands are promising building blocks for applications in reductive chemistry and catalysis.

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