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1.
Cell ; 185(26): 4971-4985.e16, 2022 12 22.
Artigo em Inglês | MEDLINE | ID: mdl-36462505

RESUMO

Intraflagellar transport (IFT) trains are massive molecular machines that traffic proteins between cilia and the cell body. Each IFT train is a dynamic polymer of two large complexes (IFT-A and -B) and motor proteins, posing a formidable challenge to mechanistic understanding. Here, we reconstituted the complete human IFT-A complex and obtained its structure using cryo-EM. Combined with AlphaFold prediction and genome-editing studies, our results illuminate how IFT-A polymerizes, interacts with IFT-B, and uses an array of ß-propeller and TPR domains to create "carriages" of the IFT train that engage TULP adaptor proteins. We show that IFT-A⋅TULP carriages are essential for cilia localization of diverse membrane proteins, as well as ICK-the key kinase regulating IFT train turnaround. These data establish a structural link between IFT-A's distinct functions, provide a blueprint for IFT-A in the train, and shed light on how IFT evolved from a proto-coatomer ancestor.


Assuntos
Cílios , Cinesinas , Humanos , Cílios/metabolismo , Transporte Biológico , Cinesinas/metabolismo , Dineínas/metabolismo , Proteínas de Membrana/metabolismo , Transporte Proteico , Flagelos/metabolismo
2.
EMBO J ; 43(7): 1257-1272, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38454149

RESUMO

Dynein-2 is a large multiprotein complex that powers retrograde intraflagellar transport (IFT) of cargoes within cilia/flagella, but the molecular mechanism underlying this function is still emerging. Distinctively, dynein-2 contains two identical force-generating heavy chains that interact with two different intermediate chains (WDR34 and WDR60). Here, we dissect regulation of dynein-2 function by WDR34 and WDR60 using an integrative approach including cryo-electron microscopy and CRISPR/Cas9-enabled cell biology. A 3.9 Å resolution structure shows how WDR34 and WDR60 use surprisingly different interactions to engage equivalent sites of the two heavy chains. We show that cilia can assemble in the absence of either WDR34 or WDR60 individually, but not both subunits. Dynein-2-dependent distribution of cargoes depends more strongly on WDR60, because the unique N-terminal extension of WDR60 facilitates dynein-2 targeting to cilia. Strikingly, this N-terminal extension can be transplanted onto WDR34 and retain function, suggesting it acts as a flexible tether to the IFT "trains" that assemble at the ciliary base. We discuss how use of unstructured tethers represents an emerging theme in IFT train interactions.


Assuntos
Cílios , Dineínas , Dineínas/metabolismo , Microscopia Crioeletrônica , Transporte Biológico , Cílios/metabolismo , Flagelos/metabolismo
3.
Cell ; 150(5): 975-86, 2012 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-22939623

RESUMO

The lissencephaly protein Lis1 has been reported to regulate the mechanical behavior of cytoplasmic dynein, the primary minus-end-directed microtubule motor. However, the regulatory mechanism remains poorly understood. Here, we address this issue using purified proteins from Saccharomyces cerevisiae and a combination of techniques, including single-molecule imaging and single-particle electron microscopy. We show that rather than binding to the main ATPase site within dynein's AAA+ ring or its microtubule-binding stalk directly, Lis1 engages the interface between these elements. Lis1 causes individual dynein motors to remain attached to microtubules for extended periods, even during cycles of ATP hydrolysis that would canonically induce detachment. Thus, Lis1 operates like a "clutch" that prevents dynein's ATPase domain from transmitting a detachment signal to its track-binding domain. We discuss how these findings provide a conserved mechanism for dynein functions in living cells that require prolonged microtubule attachments.


Assuntos
1-Alquil-2-acetilglicerofosfocolina Esterase/metabolismo , Dineínas/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , 1-Alquil-2-acetilglicerofosfocolina Esterase/química , 1-Alquil-2-acetilglicerofosfocolina Esterase/genética , Sequência de Aminoácidos , Animais , Dineínas/química , Humanos , Proteínas Associadas aos Microtúbulos/química , Proteínas Associadas aos Microtúbulos/genética , Microtúbulos/metabolismo , Modelos Moleculares , Dados de Sequência Molecular , Estrutura Terciária de Proteína , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo
4.
EMBO J ; 41(16): e110410, 2022 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-35698800

RESUMO

Although amyloid fibres are highly stable protein aggregates, a specific combination of human Hsp70 system chaperones can disassemble them, including fibres formed of α-synuclein, huntingtin, or Tau. Disaggregation requires the ATPase activity of the constitutively expressed Hsp70 family member, Hsc70, together with the J domain protein DNAJB1 and the nucleotide exchange factor Apg2. Clustering of Hsc70 on the fibrils appears to be necessary for disassembly. Here we use atomic force microscopy to show that segments of in vitro assembled α-synuclein fibrils are first coated with chaperones and then undergo bursts of rapid, unidirectional disassembly. Cryo-electron tomography and total internal reflection fluorescence microscopy reveal fibrils with regions of densely bound chaperones, preferentially at one end of the fibre. Sub-stoichiometric amounts of Apg2 relative to Hsc70 dramatically increase recruitment of Hsc70 to the fibres, creating localised active zones that then undergo rapid disassembly at a rate of ~ 4 subunits per second. The observed unidirectional bursts of Hsc70 loading and unravelling may be explained by differences between the two ends of the polar fibre structure.


Assuntos
Proteínas de Choque Térmico HSP70 , alfa-Sinucleína , Amiloide/metabolismo , Proteínas Amiloidogênicas/metabolismo , Proteínas de Choque Térmico HSC70/metabolismo , Proteínas de Choque Térmico HSP40/metabolismo , Proteínas de Choque Térmico HSP70/metabolismo , Humanos , Chaperonas Moleculares/metabolismo , Agregados Proteicos , Ligação Proteica , alfa-Sinucleína/metabolismo
5.
J Cell Sci ; 137(8)2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38533689

RESUMO

Primary cilia are essential eukaryotic organelles required for signalling and secretion. Dynein-2 is a microtubule-motor protein complex and is required for ciliogenesis via its role in facilitating retrograde intraflagellar transport (IFT) from the cilia tip to the cell body. Dynein-2 must be assembled and loaded onto IFT trains for entry into cilia for this process to occur, but how dynein-2 is assembled and how it is recycled back into a cilium remain poorly understood. Here, we identify centrosomal protein of 170 kDa (CEP170) as a dynein-2-interacting protein in mammalian cells. We show that loss of CEP170 perturbs intraflagellar transport and hedgehog signalling, and alters the stability of dynein-2 holoenzyme complex. Together, our data indicate a role for CEP170 in supporting cilia function and dynein-2 assembly.


Assuntos
Cílios , Proteínas Associadas aos Microtúbulos , Cílios/metabolismo , Humanos , Proteínas Associadas aos Microtúbulos/metabolismo , Proteínas Associadas aos Microtúbulos/genética , Animais , Dineínas/metabolismo , Dineínas/genética , Proteínas Hedgehog/metabolismo , Proteínas Hedgehog/genética , Transdução de Sinais , Camundongos , Flagelos/metabolismo
6.
Circulation ; 2024 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-38940005

RESUMO

BACKGROUND: Current estimates of atrial fibrillation (AF)-associated mortality rely on claims- or clinical-derived diagnoses of AF, limit AF to a binary entity, or are confounded by comorbidities. The objective of the present study is to assess the association between device-recognized AF and mortality among patients with cardiac implantable electronic devices capable of sensitive and continuous atrial arrhythmia detection. Secondary outcomes include relative mortality among cohorts with no AF, paroxysmal AF, persistent AF, and permanent AF. METHODS: Using the deidentified Optum Clinformatics US claims database (2015 to 2020) linked to the Medtronic CareLink database, we identified individuals with a cardiac implantable electronic device who transmitted data ≥6 months after implantation. AF burden was assessed during the first 6 months after implantation (baseline period). Subsequent mortality, assessed from claims data, was compared between patients with and those without AF, with adjustment for age, geographic region, insurance type, Charlson Comorbidity Index, and implantation year. RESULTS: Of 21 391 patients (age, 72.9±10.9 years; 56.3% male) analyzed, 7798 (36.5%) had device-recognized AF. During a mean of 22.4±12.9 months (median, 20.1 [12.8-29.7] months) of follow-up, the overall incidence of mortality was 13.5%. Patients with AF had higher adjusted all-cause mortality than patients without AF (hazard ratio, 1.29 [95% CI, 1.20-1.39]; P<0.001). Among those with AF, patients with nonparoxysmal AF had the greatest risk of mortality (persistent AF versus paroxysmal AF: hazard ratio, 1.36 [95% CI, 1.18-1.58]; P<.001; permanent AF versus paroxysmal AF: hazard ratio, 1.23 [95% CI, 1.14-1.34]; P<.001). CONCLUSIONS: After adjustment for potential confounding factors, presence of AF was associated with higher mortality than no AF in our cohort of patients with cardiac implantable electronic devices. Among those with AF, nonparoxysmal AF was associated with the greatest risk of mortality.

7.
J Cell Sci ; 136(5)2023 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-36268591

RESUMO

The primary cilium is a sensory organelle, receiving signals from the external environment and relaying them into the cell. Mutations in proteins required for transport in the primary cilium result in ciliopathies, a group of genetic disorders that commonly lead to the malformation of organs such as the kidney, liver and eyes and skeletal dysplasias. The motor proteins dynein-2 and kinesin-2 mediate retrograde and anterograde transport, respectively, in the cilium. WDR34 (also known as DYNC2I2), a dynein-2 intermediate chain, is required for the maintenance of cilia function. Here, we investigated WDR34 mutations identified in Jeune syndrome, short-rib polydactyly syndrome and asphyxiating thoracic dysplasia patients. There is a poor correlation between genotype and phenotype in these cases, making diagnosis and treatment highly complex. We set out to define the biological impacts on cilia formation and function of WDR34 mutations by stably expressing the mutant proteins in WDR34-knockout cells. WDR34 mutations led to different spectrums of phenotypes. Quantitative proteomics demonstrated changes in dynein-2 assembly, whereas initiation and extension of the axoneme, localization of intraflagellar transport complex-B proteins, transition zone integrity and Hedgehog signalling were also affected.


Assuntos
Dineínas , Síndrome de Ellis-Van Creveld , Humanos , Dineínas/genética , Dineínas/metabolismo , Proteínas de Transporte/metabolismo , Proteínas Hedgehog/metabolismo , Síndrome de Ellis-Van Creveld/genética , Síndrome de Ellis-Van Creveld/metabolismo , Cílios/genética , Cílios/metabolismo , Mutação/genética
8.
Nat Rev Mol Cell Biol ; 14(11): 713-26, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24064538

RESUMO

Fuelled by ATP hydrolysis, dyneins generate force and movement on microtubules in a wealth of biological processes, including ciliary beating, cell division and intracellular transport. The large mass and complexity of dynein motors have made elucidating their mechanisms a sizable task. Yet, through a combination of approaches, including X-ray crystallography, cryo-electron microscopy, single-molecule assays and biochemical experiments, important progress has been made towards understanding how these giant motor proteins work. From these studies, a model for the mechanochemical cycle of dynein is emerging, in which nucleotide-driven flexing motions within the AAA+ ring of dynein alter the affinity of its microtubule-binding stalk and reshape its mechanical element to generate movement.


Assuntos
Dineínas/metabolismo , Animais , Dineínas/química , Humanos , Modelos Biológicos
9.
Cell ; 136(3): 485-95, 2009 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-19203583

RESUMO

Dynein ATPases power diverse microtubule-based motilities. Each dynein motor domain comprises a ring-like head containing six AAA+ modules and N- and C-terminal regions, together with a stalk that binds microtubules. How these subdomains are arranged and generate force remains poorly understood. Here, using electron microscopy and image processing of tagged and truncated Dictyostelium cytoplasmic dynein constructs, we show that the heart of the motor is a hexameric ring of AAA+ modules, with the stalk emerging opposite the primary ATPase site (AAA1). The C-terminal region is not an integral part of the ring but spans between AAA6 and near the stalk base. The N-terminal region includes a lever-like linker whose N terminus swings by approximately 17 nm during the ATPase cycle between AAA2 and the stalk base. Together with evidence of stalk tilting, which may communicate changes in microtubule binding affinity, these findings suggest a model for dynein's structure and mechanism.


Assuntos
Dictyostelium/ultraestrutura , Dineínas/metabolismo , Proteínas de Protozoários/metabolismo , Animais , Dictyostelium/metabolismo , Dineínas/ultraestrutura , Proteínas de Fluorescência Verde/metabolismo , Microscopia Eletrônica , Proteínas de Protozoários/ultraestrutura
10.
J Clin Periodontol ; 51(5): 571-582, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38233039

RESUMO

AIM: To investigate the prevalence of gingivitis and periodontitis, and the oral hygiene status of adults with cystic fibrosis (CF) in the Republic of Ireland. MATERIALS AND METHODS: A case-control study in the form of a clinical examination of 92 adults with a diagnosis of CF was carried out in the adult CF unit in Cork University Hospital. A 40-item questionnaire was used to capture socio-demographic variables and medical and dental information. Two calibrated examiners carried out a periodontal assessment on participants, using the WHO-recommended CPI-modified index, and oral hygiene status was measured using the Greene-Vermillion index. The results were compared with a population-based control group of similar socio-demographic profile. RESULTS: Oral hygiene levels (plaque and calculus) were significantly worse in people with CF, with a median plaque index of 0.83 (interquartile range [IQR] 0.333-1.542) in the CF group compared with 0.5 (IQR 0.167-0.667) in the non-CF group. Calculus index in the CF group was 0.33 (IQR 0.17-0.83) compared with 0.33 (IQR 0.125-0.33) in the non-CF group. However, periodontal disease levels were significantly lower in the CF group. Gingivitis (bleeding on probing ≥ 10% sites) was seen in 67.4% of the CF group, compared with 83.7% of the non-CF group, OR 0.365 (95% confidence interval [CI] 0.181-0.736), relative risk (RR) 0.779 (95% CI 0.655-0.928). Mild periodontitis (periodontal probing depth [PPD] < 5 mm) was seen in 15.2% of the CF group, compared with 31.5% of the non-CF group, OR 0.390 (CI 0.190-0.800), RR 0.483 (95% CI 0.273-0.852). Severe periodontitis (PPD ≥ 6 mm) was seen in 0% of the CF group, compared with 9.8% of the non-CF group. There was a tendency, albeit non-significant, towards reduced periodontitis in PWCF who regularly took antibiotics, particularly azithromycin. CONCLUSIONS: In this study, adults with CF had poor oral hygiene practices, with high levels of plaque and calculus. Despite this finding, adults with CF had lower levels of clinical gingivitis and periodontitis than seen in a non-CF control group. Further study is required to examine the causes of this phenomenon.


Assuntos
Cálculos , Fibrose Cística , Placa Dentária , Gengivite , Doenças Periodontais , Periodontite , Adulto , Humanos , Higiene Bucal/métodos , Prevalência , Fibrose Cística/complicações , Fibrose Cística/epidemiologia , Estudos de Casos e Controles , Doenças Periodontais/epidemiologia , Gengivite/epidemiologia
11.
J Clin Periodontol ; 2024 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-38724458

RESUMO

AIM: The 1st European Workshop on Periodontal Education in 2009 made recommendations regarding the scope of periodontal education at undergraduate (UG), postgraduate (PG) and continuing professional development (CPD) levels, defining competencies and learning outcomes that were instrumental at the time in helping to define periodontal teaching curricula. The 19th European Workshop on Periodontology and 2nd European Consensus Workshop on Education in Periodontology (Education in Periodontology in Europe) was held in 2023 to identify changes and future developments in periodontal education (including those informed by the COVID-19 pandemic) and embracing methods and formats of periodontal teaching and training. The aim of this review was to assess current knowledge regarding education methods in periodontology, including traditional face-to-face (F2F) teaching and the move to student-centred methods, virtual learning methods and use of digital technology, as well as blended teaching and learning (including teaching delivery and assessment) at UG, PG and CPD levels. MATERIALS AND METHODS: Systematic searches were conducted to identify relevant studies from the literature. Data were extracted and descriptive summaries collated. RESULTS: The pandemic was a major disruptor of traditional F2F teaching but provided opportunities for rapid implementation of alternative and supplementary teaching methods. Although online learning has become an integral part of periodontal education, teachers and learners alike favour some form of F2F teaching. Blended teaching and learning are feasible in many areas of periodontal education, both for knowledge and skills acquisition as well as in assessment. Student-centred methods and blended approaches such as the flipped classroom seem highly effective, and online/virtual classrooms with both synchronous and asynchronous lectures are highly valued. Learning with haptic methods and virtual reality (VR) enhances the educational experience, especially when VR is integrated with traditional methods. The quality of the teacher continues to be decisive for the best knowledge transfer in all its forms. CONCLUSIONS: Live F2F teaching continues to be highly trusted; however, all types of student-centred and interactive forms of knowledge transfer are embraced as enhancements. While digital methods offer innovation in education, blended approaches integrating both virtual and traditional methods appear optimal to maximize the achievement of learning outcomes. All areas of periodontal education (UG, PG and CPD) can benefit from such approaches; however, more research is needed to evaluate their benefits, both for knowledge transfer and skills development, as well as in assessment.

12.
Clin Transplant ; 37(11): e15086, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37555329

RESUMO

BACKGROUND: Solid organ transplant provides a lifeline for people with end stage organ failure. Each year the number of individuals in receipt of a solid organ transplant is increasing. Prevention of post-transplant sepsis and infection are critical for transplant success. The oral cavity contains more than 700 different species of bacteria and is a potential reservoir for disease causing pathogens. Prior to undergoing solid organ transplant, individuals must receive a certification of dental health from a dental practitioner. There are currently no guidelines or protocols for dental practitioners to follow when certifying a patient as dentally fit. This allows for a wide variation of the term 'dentally fit'. This survey was conducted as part of a larger study assessing the oral health of adults with cystic fibrosis ongoing in Cork University Dental School and Hospital. The aim of the study was to ascertain current practices and attitudes of dental practitioners regarding the provision of dental treatment pre and post solid organ transplantation. METHODS: An anonymous cross sectional survey of dental practitioners in Ireland was conducted. RESULTS: The data collected showed a wide variation in the provision of treatment for patient undergoing or in receipt of a solid organ transplant. CONCLUSION: It demonstrates a need for further research to be conducted to ascertain the full impact solid organ transplant has on oral health, so that guidelines can be developed to aid both dental and medical professionals in the treatment of this vulnerable cohort.


Assuntos
Odontólogos , Transplante de Órgãos , Adulto , Humanos , Estudos Transversais , Papel Profissional , Transplante de Órgãos/efeitos adversos , Assistência Odontológica
13.
Ecol Appl ; 33(3): e2788, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36482795

RESUMO

Management of waterfowl that migrate seasonally across North America occurs within four flyways that were delineated in the early 1900s to include the annual movements of populations. Movements may have changed over the past century since the administrative flyways were established, and may do so while management plans are in use, so information about transitions among flyways through time can illustrate how management assumptions may change. Today there are more than 12 million records from 60 years of migratory waterfowl band recoveries to assess adaptive management approaches that will be most effective when they account for movements within and between flyways. We examined how much the movement of North American waterfowl occurs between flyways, whether those movements have changed through time, and whether movements of mallards are representative of multiple species, as suggested by current harvest management strategies. We estimated the probability a duck would transition from one flyway to another and the strength of migratory connectivity (MC) for each species within and among flyways. We used capture-mark-recovery models to estimate population-specific movement within and among flyways (transition probabilities) for 15 migratory waterfowl species that were banded during breeding and recovered during winter. We developed new functionality in the R package MigConnectivity to estimate the species-specific strength of MC using transition probability samples from the capture-mark-recovery models. We found the regular movement of duck populations among flyways, overall weak MC, and no consistent change in migratory movements through time. Mallard movements were median among all duck species, but significantly different from many species, particularly diving ducks. Despite the significant movement between flyways, our work suggests flyway management of waterfowl matches many of the seasonal movements of these species when considering mid-continent flyway management. We recommend models accounting for all transition probabilities between populations and regularly estimating harvest derivations, transition probabilities, and MC metrics to verify that the current movements match model assumptions.


Assuntos
Migração Animal , Patos , Animais , América do Norte , Estações do Ano , Probabilidade
14.
Semin Cell Dev Biol ; 107: 82-90, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32684327

RESUMO

Intraflagellar transport (IFT) sculpts the proteome of cilia and flagella; the antenna-like organelles found on the surface of virtually all human cell types. By delivering proteins to the growing ciliary tip, recycling turnover products, and selectively transporting signalling molecules, IFT has critical roles in cilia biogenesis, quality control, and signal transduction. IFT involves long polymeric arrays, termed IFT trains, which move to and from the ciliary tip under the power of the microtubule-based motor proteins kinesin-II and dynein-2. Recent top-down and bottom-up structural biology approaches are converging on the molecular architecture of the IFT train machinery. Here we review these studies, with a focus on how kinesin-II and dynein-2 assemble, attach to IFT trains, and undergo precise regulation to mediate bidirectional transport.


Assuntos
Flagelos/metabolismo , Proteínas Motores Moleculares/metabolismo , Animais , Transporte Biológico , Humanos , Microtúbulos/metabolismo , Modelos Biológicos
15.
J Biol Chem ; 297(5): 101063, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34375637

RESUMO

Plasmodium parasites cause malaria and are responsible annually for hundreds of thousands of deaths. Kinesins are a superfamily of microtubule-dependent ATPases that play important roles in the parasite replicative machinery, which is a potential target for antiparasite drugs. Kinesin-5, a molecular motor that cross-links microtubules, is an established antimitotic target in other disease contexts, but its mechanism in Plasmodium falciparum is unclear. Here, we characterized P. falciparum kinesin-5 (PfK5) using cryo-EM to determine the motor's nucleotide-dependent microtubule-bound structure and introduced 3D classification of individual motors into our microtubule image processing pipeline to maximize our structural insights. Despite sequence divergence in PfK5, the motor exhibits classical kinesin mechanochemistry, including ATP-induced subdomain rearrangement and cover neck bundle formation, consistent with its plus-ended directed motility. We also observed that an insertion in loop5 of the PfK5 motor domain creates a different environment in the well-characterized human kinesin-5 drug-binding site. Our data reveal the possibility for selective inhibition of PfK5 and can be used to inform future exploration of Plasmodium kinesins as antiparasite targets.


Assuntos
Cinesinas , Plasmodium falciparum , Proteínas de Protozoários , Antimaláricos/química , Microscopia Crioeletrônica , Humanos , Cinesinas/metabolismo , Cinesinas/ultraestrutura , Plasmodium falciparum/química , Plasmodium falciparum/metabolismo , Plasmodium falciparum/ultraestrutura , Proteínas de Protozoários/química , Proteínas de Protozoários/metabolismo , Proteínas de Protozoários/ultraestrutura
16.
J Cell Sci ; 133(6)2020 03 30.
Artigo em Inglês | MEDLINE | ID: mdl-32229580

RESUMO

Cytoplasmic dynein-2 is a motor protein complex that drives the movement of cargoes along microtubules within cilia, facilitating the assembly of these organelles on the surface of nearly all mammalian cells. Dynein-2 is crucial for ciliary function, as evidenced by deleterious mutations in patients with skeletal abnormalities. Long-standing questions include how the dynein-2 complex is assembled, regulated, and switched between active and inactive states. A combination of model organisms, in vitro cell biology, live-cell imaging, structural biology and biochemistry has advanced our understanding of the dynein-2 motor. In this Cell Science at a Glance article and the accompanying poster, we discuss the current understanding of dynein-2 and its roles in ciliary assembly and function.


Assuntos
Dineínas do Citoplasma , Dineínas , Animais , Transporte Biológico , Cílios/metabolismo , Dineínas do Citoplasma/genética , Dineínas do Citoplasma/metabolismo , Dineínas/genética , Dineínas/metabolismo , Humanos , Cinesinas/metabolismo , Microtúbulos/metabolismo
17.
Gerodontology ; 39(4): 354-358, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34569084

RESUMO

OBJECTIVES: The objectives of this article are to list the most commonly prescribed Oral Nutritional Supplements in the UK and Ireland and their sugar content; and to raise awareness among the dental profession regarding their uses and potential dental risks involved. BACKGROUND: Many older patients benefit from Oral Nutritional Supplements. Prescribers may not consider dental implications of these. Patients may not think to disclose these medications to their dentist. MATERIALS AND METHODS: A list of commonly prescribed Oral Nutritional Supplements in the UK and Ireland was compiled. Nutritional information was obtained from the manufacturers' website and arranged in order of decreasing sugar content. Potential dental implications are discussed and recommendations made for dental practitioners. RESULTS: Pre-formed Oral Nutritional Supplements can contain between 6.6 and 27.2 g of sugar per serving. Powdered Oral Nutritional Supplements, which are to be mixed with 200 ml whole milk, contain between 16.4 and 35.0 g sugar per serving. The "shot"-type Oral Nutritional Supplements contain less sugar, ranging from 0.0 to 4.0 g per serving. CONCLUSIONS: The sugar content of frequently prescribed Oral Nutritional Supplements can be high. While they are beneficial in assisting the patient to maintain a healthy BMI, they may increase the risk of dental caries. Dental professionals should enquire specifically about Oral Nutritional Supplements during history taking, particularly in groups who are likely to be prescribed such supplements. Consideration should also be given to increasing caries-preventive measures for patients who take these supplements.


Assuntos
Cárie Dentária , Açúcares , Humanos , Cárie Dentária/etiologia , Cárie Dentária/prevenção & controle , Odontólogos , Papel Profissional , Irlanda
18.
PLoS Pathog ; 15(10): e1008048, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31600347

RESUMO

Kinesin-8 proteins are microtubule motors that are often involved in regulation of mitotic spindle length and chromosome alignment. They move towards the plus ends of spindle microtubules and regulate the dynamics of these ends due, at least in some species, to their microtubule depolymerization activity. Plasmodium spp. exhibit an atypical endomitotic cell division in which chromosome condensation and spindle dynamics in the different proliferative stages are not well understood. Genome-wide shared orthology analysis of Plasmodium spp. revealed the presence of two kinesin-8 motor proteins, kinesin-8X and kinesin-8B. Here we studied the biochemical properties of kinesin-8X and its role in parasite proliferation. In vitro, kinesin-8X has motility and depolymerization activities like other kinesin-8 motors. To understand the role of Plasmodium kinesin-8X in cell division, we used fluorescence-tagging and live cell imaging to define its location, and gene targeting to analyse its function, during all proliferative stages of the rodent malaria parasite P. berghei life cycle. The results revealed a spatio-temporal involvement of kinesin-8X in spindle dynamics and an association with both mitotic and meiotic spindles and the putative microtubule organising centre (MTOC). Deletion of the kinesin-8X gene revealed a defect in oocyst development, confirmed by ultrastructural studies, suggesting that this protein is required for oocyst development and sporogony. Transcriptome analysis of Δkinesin-8X gametocytes revealed modulated expression of genes involved mainly in microtubule-based processes, chromosome organisation and the regulation of gene expression, supporting a role for kinesin-8X in cell division. Kinesin-8X is thus required for parasite proliferation within the mosquito and for transmission to the vertebrate host.


Assuntos
Cinesinas/metabolismo , Malária/parasitologia , Malária/transmissão , Oocistos/citologia , Plasmodium/fisiologia , Proteínas de Protozoários/metabolismo , Fuso Acromático/fisiologia , Animais , Segregação de Cromossomos , Feminino , Cinesinas/genética , Masculino , Camundongos Endogâmicos BALB C , Microtúbulos/metabolismo , Mitose , Oocistos/fisiologia , Proteínas de Protozoários/genética
19.
Genet Med ; 22(12): 2041-2051, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32753734

RESUMO

PURPOSE: Determining the role of DYNC2H1 variants in nonsyndromic inherited retinal disease (IRD). METHODS: Genome and exome sequencing were performed for five unrelated cases of IRD with no identified variant. In vitro assays were developed to validate the variants identified (fibroblast assay, induced pluripotent stem cell [iPSC] derived retinal organoids, and a dynein motility assay). RESULTS: Four novel DYNC2H1 variants (V1, g.103327020_103327021dup; V2, g.103055779A>T; V3, g.103112272C>G; V4, g.103070104A>C) and one previously reported variant (V5, g.103339363T>G) were identified. In proband 1 (V1/V2), V1 was predicted to introduce a premature termination codon (PTC), whereas V2 disrupted the exon 41 splice donor site causing incomplete skipping of exon 41. V1 and V2 impaired dynein-2 motility in vitro and perturbed IFT88 distribution within cilia. V3, homozygous in probands 2-4, is predicted to cause a PTC in a retina-predominant transcript. Analysis of retinal organoids showed that this new transcript expression increased with organoid differentiation. V4, a novel missense variant, was in trans with V5, previously associated with Jeune asphyxiating thoracic dystrophy (JATD). CONCLUSION: The DYNC2H1 variants discussed herein were either hypomorphic or affecting a retina-predominant transcript and caused nonsyndromic IRD. Dynein variants, specifically DYNC2H1 variants are reported as a cause of non syndromic IRD.


Assuntos
Síndrome de Ellis-Van Creveld , Degeneração Retiniana , Dineínas do Citoplasma/genética , Síndrome de Ellis-Van Creveld/genética , Éxons , Humanos , Mutação , Linhagem , Retina , Degeneração Retiniana/genética
20.
Transfusion ; 60(12): 2828-2833, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32989778

RESUMO

BACKGROUND: Arkansas is a rural state of 3 million people. It is ranked fifth for poverty nationally. The first case of coronavirus disease 2019 (COVID-19) in Arkansas occurred on 11 March 2020. Since then, approximately 8% of all Arkansans have tested positive. Given the resource limitations of Arkansas, COVID-19 convalescent plasma (CCP) was explored as a potentially lifesaving, therapeutic option. Therefore, the Arkansas Initiative for Convalescent Plasma was developed to ensure that every Arkansan has access to this therapy. STUDY DESIGN AND METHOD: This brief report describes the statewide collaborative response from hospitals, blood collectors, and the Arkansas Department of Health (ADH) to ensure that CCP was available in a resource-limited state. RESULTS: Early contact tracing by ADH identified individuals who had come into contact with "patient zero" in early March. Within the first week, 32 patients tested positive for COVID-19. The first set of CCP collections occurred on 9 April 2020. Donors had to be triaged carefully in the initial period, as many had recently resolved their symptoms. From our first collections, with appropriate resource and inventory management, we collected sufficient CCP to provide the requested number of units for every patient treated with CCP in Arkansas. CONCLUSIONS: The Arkansas Initiative, a statewide effort to ensure CCP for every patient in a resource-limited state, required careful coordination among key players. Collaboration and resource management was crucial to meet the demand of CCP products and potentially save lives.


Assuntos
COVID-19/terapia , Recursos em Saúde/provisão & distribuição , Acessibilidade aos Serviços de Saúde/organização & administração , Pandemias , Alocação de Recursos/organização & administração , SARS-CoV-2/imunologia , Anticorpos Antivirais/sangue , Arkansas/epidemiologia , Bancos de Sangue/economia , Bancos de Sangue/organização & administração , Doadores de Sangue/provisão & distribuição , COVID-19/sangue , COVID-19/economia , COVID-19/epidemiologia , Planejamento em Saúde Comunitária/economia , Planejamento em Saúde Comunitária/organização & administração , Busca de Comunicante , Convalescença , Recursos em Saúde/economia , Acessibilidade aos Serviços de Saúde/economia , Humanos , Imunização Passiva , Colaboração Intersetorial , Pobreza , Alocação de Recursos/economia , População Rural , Soroterapia para COVID-19
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