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1.
Cell Rep ; 43(9): 114718, 2024 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-39277859

RESUMO

Large-scale analysis of single-cell gene expression has revealed transcriptomically defined cell subclasses present throughout the primate neocortex with gene expression profiles that differ depending upon neocortical region. Here, we test whether the interareal differences in gene expression translate to regional specializations in the physiology and morphology of infragranular glutamatergic neurons by performing Patch-seq experiments in brain slices from the temporal cortex (TCx) and motor cortex (MCx) of the macaque. We confirm that transcriptomically defined extratelencephalically projecting neurons of layer 5 (L5 ET neurons) include retrogradely labeled corticospinal neurons in the MCx and find multiple physiological properties and ion channel genes that distinguish L5 ET from non-ET neurons in both areas. Additionally, while infragranular ET and non-ET neurons retain distinct neuronal properties across multiple regions, there are regional morpho-electric and gene expression specializations in the L5 ET subclass, providing mechanistic insights into the specialized functional architecture of the primate neocortex.

2.
Development ; 151(16)2024 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-39190553

RESUMO

The size of subcellular structures must be tightly controlled to maintain normal cell function. Despite its importance, few studies have determined how the size of organelles or other structures is maintained during development, when cells are growing, dividing and rearranging. The developing Drosophila egg chamber is a powerful model in which to study the relative growth rates of subcellular structures. The egg chamber contains a cluster of 16 germline cells, which are connected through intercellular bridges called ring canals. As the egg chamber grows, the germline cells and the ring canals that connect them increase in size. Here, we demonstrate that ring canal size scaling is related to lineage; the largest, 'first-born' ring canals increase in size at a relatively slower rate than ring canals derived from subsequent mitotic divisions. This lineage-based scaling relationship is maintained even if directed transport is reduced, ring canal size is altered, or in egg chambers with twice as many germline cells. Analysis of lines that produce larger or smaller mature eggs reveals that different strategies could be used to alter final egg size.


Assuntos
Linhagem da Célula , Células Germinativas , Oogênese , Animais , Oogênese/fisiologia , Feminino , Células Germinativas/citologia , Drosophila melanogaster , Drosophila , Óvulo/citologia , Tamanho Celular
3.
Sci Adv ; 10(32): eadn5181, 2024 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-39110801

RESUMO

Episodic memory in older adults is varied and perceived to rely on numbers of synapses or dendritic spines. We analyzed 2157 neurons among 128 older individuals from the Religious Orders Study and Rush Memory and Aging Project. Analysis of 55,521 individual dendritic spines by least absolute shrinkage and selection operator regression and nested model cross-validation revealed that the dendritic spine head diameter in the temporal cortex, but not the premotor cortex, improved the prediction of episodic memory performance in models containing ß amyloid plaque scores, neurofibrillary tangle pathology, and sex. These findings support the emerging hypothesis that, in the temporal cortex, synapse strength is more critical than quantity for memory in old age.


Assuntos
Espinhas Dendríticas , Memória Episódica , Humanos , Espinhas Dendríticas/fisiologia , Masculino , Feminino , Idoso , Idoso de 80 Anos ou mais , Envelhecimento/fisiologia , Lobo Temporal/fisiologia , Placa Amiloide/patologia
4.
JMIR Form Res ; 8: e54723, 2024 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-39083340

RESUMO

BACKGROUND: Digital health interventions show promise for weight management. However, few text-based behavior change interventions have been designed to support patients receiving intragastric balloons, and none have simultaneously evaluated weight loss, psychological well-being, and behavior change despite the crucial interplay of these factors in weight management. OBJECTIVE: This study aims to assess whether a health coach-led, asynchronous, text-based digital behavior change coaching intervention (DBCCI) delivered to participants receiving an intragastric balloon and its aftercare program was feasible and acceptable to participants and supported improved outcomes, including weight loss, psychological well-being, and lifestyle behavior change conducive to weight loss maintenance. METHODS: This 12-month, single-arm prospective study enrolled adults aged 21 to 65 years with BMI ≥27 kg/m2 receiving a procedureless intragastric balloon (PIGB) at 5 bariatric clinics in the United Kingdom and the Netherlands. Participants received the DBCCI and the clinic-led PIGB aftercare program (remotely delivered) for 6 months after PIGB placement and then no intervention for an additional 6 months. The DBCCI was an evidence-based, personalized intervention wherein health coaches supported participants via exchanged asynchronous in-app text-based messages. Over the 12-month study, we assessed percentage of total body weight loss and psychological well-being via self-administered validated questionnaires (Warwick-Edinburgh Mental Wellbeing Scale, Generalized Anxiety Disorder Scale, Impact of Weight on Quality of Life-Lite-Clinical Trials Version, Loss of Control Over Eating Scale-Brief, Weight Efficacy Lifestyle Questionnaire-Short Form, and Barriers to Being Active Quiz). Participant engagement with and acceptability of the intervention were assessed via self-reported surveys. RESULTS: Overall, 107 participants (n=96, 89.7% female; mean baseline BMI 35.4, SD 5.4 kg/m2) were included in the analysis. Mean total body weight loss was 13.5% (SEM 2.3%) at the end of the DBCCI and 11.22% (SEM 2.3%) at the 12-month follow-up (P<.001). Improvements were observed for all psychological well-being measures throughout the 12 months except for the Generalized Anxiety Disorder Scale (improvement at month 1) and Barriers to Being Active Quiz (improvements at months 3 and 6). Surveys showed high levels of engagement with and acceptability of the DBCCI. CONCLUSIONS: This study provides evidence that the health coach-led, asynchronous, text-based DBCCI was engaging and acceptable to participants with overweight and obesity. The DBCCI, delivered alongside the PIGB and its aftercare program, supported improved weight loss outcomes and psychological well-being versus baseline and was associated with lifestyle behavior changes known to help achieve and maintain long-term weight loss and improved health outcomes. Follow-up findings suggest a potential need for longer-term, more intense coaching to focus on weight loss maintenance and support ongoing self-coaching. This could be achieved by leveraging generative artificial intelligence to provide ongoing automated behavior change coaching support to augment human-led care. TRIAL REGISTRATION: ClinicalTrials.gov NCT05884606; https://clinicaltrials.gov/study/NCT05884606.

5.
Drug Discov Today ; 29(5): 103943, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38452922

RESUMO

The drug discovery and development process encompasses the interrogation of metabolites arising from the biotransformation of drugs. Here we look at why, when and how metabolites of small-molecule drugs are synthesised from the perspective of a specialist contract research organisation, with particular attention paid to projects for which regulatory oversight is relevant during this journey. To illustrate important aspects, we look at recent case studies, trends and learnings from our experience of making and identifying metabolites over the past ten years, along with with selected examples from the literature.


Assuntos
Descoberta de Drogas , Humanos , Preparações Farmacêuticas/metabolismo , Descoberta de Drogas/métodos , Biotransformação , Animais
6.
Cognition ; 245: 105709, 2024 04.
Artigo em Inglês | MEDLINE | ID: mdl-38232474

RESUMO

It is crucial to identify cognitive mechanisms that support knowledge growth. One such mechanism that is known to improve learning outcomes is generative processing: the construction of novel information beyond what is directly taught. In this study of college students, we investigate the learning outcomes associated with the generative process of self-derivation through integration, the integration of multiple related facts to generate novel information. We compare the effects of self-derivation versus an active rephrase control condition on retrieval, application, and organization of neuroscience classroom content. In the self-derivation condition, learners were prompted to generate inferences based on integration of two explicitly-taught facts. In the rephrase condition, learners were explicitly provided these inferences and asked to rephrase them. We found few overall differences between learning manipulation conditions. However, we found that, regardless of the learning manipulation condition to which learners were exposed, learners generated their own information on some trials. This generation predicted success on retrieval and application of learned information. Further, self-derivation, when successful, led to particularly high rates of retrieval when compared with active rephrase. These findings inform theory on generative processing, and demonstrate that self-derivation is a mechanism of knowledge growth that may be useful for retrieval.


Assuntos
Conhecimento , Aprendizagem , Humanos
7.
ACS Infect Dis ; 9(12): 2423-2435, 2023 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-37991879

RESUMO

Antimicrobial resistance (AMR) is widely acknowledged as one of the most serious public health threats facing the world, yet the private sector finds it challenging to generate much-needed medicines. As an alternative discovery approach, a small array of diarylimidazoles was screened against the ESKAPE pathogens, and the results were made publicly available through the Open Source Antibiotics (OSA) consortium (https://github.com/opensourceantibiotics). Of the 18 compounds tested (at 32 µg/mL), 15 showed >90% growth inhibition activity against methicillin-resistant Staphylococcus aureus (MRSA) alone. In the subsequent hit-to-lead optimization of this chemotype, 147 new heterocyclic compounds containing the diarylimidazole and other core motifs were synthesized and tested against MRSA, and their structure-activity relationships were identified. While potent, these compounds have moderate to high intrinsic clearance and some associated toxicity. The best overall balance of parameters was found with OSA_975, a compound with good potency, good solubility, and reduced intrinsic clearance in rat hepatocytes. We have progressed toward the knowledge of the molecular target of these phenotypically active compounds, with proteomic techniques suggesting TGFBR1 is potentially involved in the mechanism of action. Further development of these compounds toward antimicrobial medicines is available to anyone under the licensing terms of the project.


Assuntos
Antibacterianos , Staphylococcus aureus Resistente à Meticilina , Ratos , Animais , Antibacterianos/farmacologia , Proteômica , Testes de Sensibilidade Microbiana , Relação Estrutura-Atividade
8.
bioRxiv ; 2023 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-37645982

RESUMO

The size of subcellular structures must be tightly controlled to maintain normal cell function; this is especially important when cells are part of developing tissues or organs. Despite its importance, few studies have determined how the size of organelles or other structures is maintained during tissue growth, when cells are growing, dividing, and rearranging. The developing egg chamber is a powerful model in which to study the relative growth rates of subcellular structures. The egg chamber contains a cluster of sixteen germ cells, which are connected through intercellular bridges called ring canals. Ring canals are formed following incomplete cytokinesis after each of four germ cell divisions. As the egg chamber grows, the nurse cells and the ring canals that connect them increase in size. Here, we demonstrate that ring canal size scaling is related to their lineage; the largest, "first born" ring canals grow at a relatively slower rate than ring canals derived from subsequent mitotic divisions. This lineage-based scaling relationship is maintained even if directed transport is reduced, ring canal size is altered, or if the germ cells go through an additional mitotic division. Further, we propose that changes in ring canal scaling could provide a mechanism to alter egg size.

9.
Child Adolesc Psychiatr Clin N Am ; 31(3): 515-530, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35697399

RESUMO

Co-occurring ADHD and substance use disorder (SUD) is a common clinical presentation associated with significant impairment requiring careful evaluation, diagnosis, and treatment. Treatment with medication, along with cognitive behavioral therapy, is generally regarded as effective in addressing symptoms and impairments associated with both disorders. Options for pharmacotherapy include stimulant and nonstimulant therapies administered with careful monitoring of dosage and compliance to optimize efficacy. In high-risk groups such as college students and/or those with SUD, prescribers should address risks of stimulant misuse and diversion through patient and family education, medication monitoring, and other risk-reducing practices.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade , Estimulantes do Sistema Nervoso Central , Transtornos Relacionados ao Uso de Substâncias , Adolescente , Transtorno do Deficit de Atenção com Hiperatividade/diagnóstico , Transtorno do Deficit de Atenção com Hiperatividade/tratamento farmacológico , Estimulantes do Sistema Nervoso Central/efeitos adversos , Comorbidade , Humanos , Estudantes , Transtornos Relacionados ao Uso de Substâncias/tratamento farmacológico , Transtornos Relacionados ao Uso de Substâncias/terapia
11.
Mem Cognit ; 49(7): 1473-1487, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-33834383

RESUMO

What are the boundaries that limit expansion of semantic knowledge across development? One striking contender is the necessity of a prompt to integrate and self-generate new information. The present research was an investigation of 7-9-year-olds' and 18-22-year-olds' prompted versus unprompted memory integration and subsequent self-derivation of new knowledge. Children and adults (Experiments 1 and 2, respectively) were exposed to sets of novel, true facts that could be integrated to self-derive new knowledge. On some trials they were prompted to integrate and self-derive and on others they were not. Both children and young adults capitalized more effectively on prompted opportunities to self-derive compared with unprompted opportunities, and the mechanism of this difference in performance likely underlies memory integration. Thus, the current work illustrates the importance of the conditions under which memory integration occurs, regardless of age. Results also offer evidence consistent with developmental change in unprompted integration and self-derivation performance, such that children and adults may engage the process of self-derivation differently. This work is particularly important in highlighting the necessity of appropriate scaffolding to foster successful learning opportunities and understanding the conditions under which semantic knowledge is accumulated.


Assuntos
Aprendizagem , Semântica , Criança , Humanos , Conhecimento , Adulto Jovem
12.
ACS Med Chem Lett ; 11(11): 2087-2107, 2020 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-33214818

RESUMO

Biotransformation has a huge impact on the efficacy and safety of drugs. Ultimately the effects of metabolism can be the lynchpin in the discovery and development cycle of a new drug. This article discusses the impact and application of biotransformation of drugs by mammalian systems, microorganisms, and recombinant enzymes, covering active and reactive metabolites, the impact of the gut microbiome on metabolism, and how insights gained from biotransformation studies can influence drug design from the combined perspectives of a CRO specializing in a range of biotransformation techniques and pharma biotransformation scientists. We include a commentary on how biology-driven approaches can complement medicinal chemistry strategies in drug optimization and the in vitro and surrogate systems available to explore and exploit biotransformation.

13.
AoB Plants ; 12(2): plaa011, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32284842

RESUMO

The distribution and genetic structure of most plant species in Britain and Ireland bear the imprint of the last ice age. These patterns were largely shaped by random processes during recolonization but, in angiosperms, whole-genome duplication may also have been important. We investigate the distribution of cytotypes of Campanula rotundifolia, considering DNA variation, postglacial colonization, environmental partitioning and reproductive barriers. Cytotypes and genome size variation from across the species' range were determined by flow cytometry and genetic variation was assessed using cpDNA markers. A common garden study examined growth and flowering phenology of tetraploid, pentaploid and hexaploid cytotypes and simulated a contact zone for investigation of reproductive barriers. Irish populations were entirely hexaploid. In Britain, hexaploids occurred mostly in western coastal populations which were allopatric with tetraploids, and in occasional sympatric inland populations. Chloroplast markers resolved distinct genetic groups, related to cytotype and geographically segregated; allopatric hexaploids were distinct from tetraploids, whereas sympatric hexaploids were not. Genome downsizing occurred between cytotypes. Progeny of open-pollinated clones from the contact zone showed that maternal tetraploids rarely produced progeny of other cytotypes, whereas the progeny of maternal hexaploids varied, with frequent pentaploids and aneuploids. The presence of distinctive hexaploid chloroplast types in Ireland, Scottish islands and western mainland Britain indicates that its establishment preceded separation of these land masses by sea-level rise c. 16 000 years BP. This group did not originate from British tetraploids and probably diverged before postglacial invasion from mainland Europe. The combination of cytotype, molecular, contact zone and common garden data shows an overall pattern reflecting postglacial colonization events, now maintained by geographic separation, together with more recent occasional local in situ polyploidisation. Reproductive barriers favour the persistence of the tetraploid to the detriment of the hexaploid.

14.
Am J Hum Genet ; 104(1): 13-20, 2019 01 03.
Artigo em Inglês | MEDLINE | ID: mdl-30609404

RESUMO

Genomic sequencing is rapidly transitioning into clinical practice, and implementation into healthcare systems has been supported by substantial government investment, totaling over US$4 billion, in at least 14 countries. These national genomic-medicine initiatives are driving transformative change under real-life conditions while simultaneously addressing barriers to implementation and gathering evidence for wider adoption. We review the diversity of approaches and current progress made by national genomic-medicine initiatives in the UK, France, Australia, and US and provide a roadmap for sharing strategies, standards, and data internationally to accelerate implementation.


Assuntos
Atenção à Saúde/métodos , Atenção à Saúde/organização & administração , Genética Médica/métodos , Genética Médica/organização & administração , Genômica/tendências , Cooperação Internacional , Austrália , Atenção à Saúde/economia , Atenção à Saúde/tendências , Medicina Baseada em Evidências , França , Genética Médica/economia , Genética Médica/tendências , Genômica/economia , Humanos , Disseminação de Informação , Setor Privado , Reino Unido , Estados Unidos
15.
Telemed J E Health ; 25(9): 821-827, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-30407124

RESUMO

Background: Maintaining a healthy weight is a military requirement for the Reserve Officer Training Corps (ROTC) cadets. Male and female soldiers often have different approaches to maintaining a healthy weight and mobile health (m-health) tools can be harnessed and tailored to the needs of individual cadets. Objectives: This study examined gender differences in technology use, weight loss strategies, information needed to maintain a healthy weight, and willingness to participate in m-health research and programs. Materials and Methods: A self-administered survey was completed by 404 cadets from ROTC programs in Florida in 2017. Results: Most owned smartphones and used them as their primary internet access. Women had significantly lower body mass index than men (p = 0.037). Most used healthy weight loss strategies, including increasing physical activity, reducing sweets, and reducing fried foods. Women were more likely than men to reduce fried foods (p < 0.0003) and sweets (p = 0.020). Most reported a willingness to participate in m-health weight management research and programs, with women more willing to do so (p = 0.038). Most were willing to participate in m-health programs that used text messages, food/activity/sleep apps, smart watches/fitness trackers, and stress management/anxiety apps. Women were more willing to participate in programs that used apps for stress/anxiety management (p = 0.004) and to track food/activity/sleep (p < 0.0001). Most needed information on eating healthy on a budget and eating healthy on-the-run. Conclusions: Opportunities exist for college health and wellness professionals to use a variety of m-health tools and apps to promote general health and wellness and to help cadets achieve and maintain a healthy weight.


Assuntos
Índice de Massa Corporal , Promoção da Saúde/organização & administração , Militares/educação , Smartphone/estatística & dados numéricos , Redução de Peso , Adolescente , Adulto , Peso Corporal/fisiologia , Exercício Físico/fisiologia , Feminino , Florida , Educação em Saúde/métodos , Humanos , Masculino , Obesidade/prevenção & controle , Avaliação de Programas e Projetos de Saúde , Medição de Risco , Fatores Sexuais , Inquéritos e Questionários , Adulto Jovem
16.
BMJ Open ; 7(12): e018647, 2017 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-29247106

RESUMO

OBJECTIVES: We examined major issues associated with sharing of individual clinical trial data and developed a consensus document on providing access to individual participant data from clinical trials, using a broad interdisciplinary approach. DESIGN AND METHODS: This was a consensus-building process among the members of a multistakeholder task force, involving a wide range of experts (researchers, patient representatives, methodologists, information technology experts, and representatives from funders, infrastructures and standards development organisations). An independent facilitator supported the process using the nominal group technique. The consensus was reached in a series of three workshops held over 1 year, supported by exchange of documents and teleconferences within focused subgroups when needed. This work was set within the Horizon 2020-funded project CORBEL (Coordinated Research Infrastructures Building Enduring Life-science Services) and coordinated by the European Clinical Research Infrastructure Network. Thus, the focus was on non-commercial trials and the perspective mainly European. OUTCOME: We developed principles and practical recommendations on how to share data from clinical trials. RESULTS: The task force reached consensus on 10 principles and 50 recommendations, representing the fundamental requirements of any framework used for the sharing of clinical trials data. The document covers the following main areas: making data sharing a reality (eg, cultural change, academic incentives, funding), consent for data sharing, protection of trial participants (eg, de-identification), data standards, rights, types and management of access (eg, data request and access models), data management and repositories, discoverability, and metadata. CONCLUSIONS: The adoption of the recommendations in this document would help to promote and support data sharing and reuse among researchers, adequately inform trial participants and protect their rights, and provide effective and efficient systems for preparing, storing and accessing data. The recommendations now need to be implemented and tested in practice. Further work needs to be done to integrate these proposals with those from other geographical areas and other academic domains.


Assuntos
Pesquisa Biomédica/normas , Ensaios Clínicos como Assunto , Consenso , Disseminação de Informação/métodos , Comitês Consultivos , Humanos
17.
Biomed Hub ; 2(Suppl 1): 104-110, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-31988941

RESUMO

Within the decade, genome sequencing promises to become a routine part of healthcare around the globe. Many millions of genomes linked to health records will soon be available for researchers and clinicians to make use of to advance precision medicine. To realise the full impact of genomic medicine, genomic and clinical data must be interoperable across traditional geographic, jurisdictional, sectoral, and domain boundaries. Extremely large and diverse data sets are needed to provide a context for interpretation of genetic sequences. No single country or institution can achieve the necessary scale and diversity alone. Data must be shared within an internationally federated, learning health system.

18.
Artigo em Inglês | MEDLINE | ID: mdl-29311892

RESUMO

Various growth factors regulate synapse development and neurogenesis, and are essential for brain function. Changes in growth factor signaling are implicated in many neuropsychiatric disorders such as depression, autism and epilepsy. We have previously identified that fibroblast growth factor 22 (FGF22) is critical for excitatory synapse formation in several brain regions including the hippocampus. Mice with a genetic deletion of FGF22 (FGF22 null mice) have fewer excitatory synapses in the hippocampus. We have further found that as a behavioral consequence, FGF22 null mice show a depression-like behavior phenotype such as increased passive stress-coping behavior and anhedonia, without any changes in motor, anxiety, or social cognitive tests, suggesting that FGF22 is specifically important for affective behavior. Thus, addressing the precise roles of FGF22 in the brain will help understand how synaptogenic growth factors regulate affective behavior. In the hippocampus, FGF22 is expressed mainly by CA3 pyramidal neurons, but also by a subset of dentate granule cells. We find that in addition to synapse formation, FGF22 also contributes to neurogenesis in the dentate gyrus: FGF22 null mice show decreased dentate neurogenesis. To understand the cell type-specific roles of FGF22, we generated and analyzed CA3-specific FGF22 knockout mice (FGF22-CA3KO). We show that FGF22-CA3KO mice have reduced excitatory synapses on CA3 pyramidal neurons, but do not show changes in dentate neurogenesis. Behaviorally, FGF22-CA3KO mice still show increased immobility and decreased latency to float in the forced swim test and decreased preference for sucrose in the sucrose preference test, which are suggestive of a depressive-like phenotype similar to FGF22 null mice. These results demonstrate that: (i) CA3-derived FGF22 serves as a target-derived excitatory synaptic organizer in CA3 in vivo; (ii) FGF22 plays important roles in dentate neurogenesis, but CA3-derived FGF22 is not involved in neurogenesis; and (iii) a depression-like phenotype can result from FGF22 inactivation selectively in CA3 pyramidal neurons. Our results link the role of CA3-derived FGF22 in synapse development, and not in neurogenesis, to affective behavior.

19.
J Am Chem Soc ; 137(35): 11365-75, 2015 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-26317395

RESUMO

Peptides can be developed as effective antagonists of protein-protein interactions, but conventional peptides (i.e., oligomers of l-α-amino acids) suffer from significant limitations in vivo. Short half-lives due to rapid proteolytic degradation and an inability to cross cell membranes often preclude biological applications of peptides. Oligomers that contain both α- and ß-amino acid residues ("α/ß-peptides") manifest decreased susceptibility to proteolytic degradation, and when properly designed these unnatural oligomers can mimic the protein-recognition properties of analogous "α-peptides". This report documents an extension of the α/ß-peptide approach to target intracellular protein-protein interactions. Specifically, we have generated α/ß-peptides based on a "stapled" Bim BH3 α-peptide, which contains a hydrocarbon cross-link to enhance α-helix stability. We show that a stapled α/ß-peptide can structurally and functionally mimic the parent stapled α-peptide in its ability to enter certain types of cells and block protein-protein interactions associated with apoptotic signaling. However, the α/ß-peptide is nearly 100-fold more resistant to proteolysis than is the parent stapled α-peptide. These results show that backbone modification, a strategy that has received relatively little attention in terms of peptide engineering for biomedical applications, can be combined with more commonly deployed peripheral modifications such as side chain cross-linking to produce synergistic benefits.


Assuntos
Peptídeos Penetradores de Células/química , Peptídeos Penetradores de Células/farmacologia , Espaço Intracelular/efeitos dos fármacos , Espaço Intracelular/metabolismo , Dobramento de Proteína , Sequência de Aminoácidos , Animais , Proteínas Reguladoras de Apoptose/química , Proteína 11 Semelhante a Bcl-2 , Permeabilidade da Membrana Celular , Sobrevivência Celular/efeitos dos fármacos , Peptídeos Penetradores de Células/metabolismo , Citocromos c/metabolismo , Células HCT116 , Humanos , Proteínas de Membrana/química , Camundongos , Modelos Moleculares , Dados de Sequência Molecular , Peptídeo Hidrolases/metabolismo , Ligação Proteica/efeitos dos fármacos , Estabilidade Proteica , Estrutura Terciária de Proteína , Proteólise , Proteínas Proto-Oncogênicas/química
20.
AoB Plants ; 72015 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-25680798

RESUMO

Knowledge of rangewide variation in DNA content and ploidy level may be valuable in understanding the evolutionary history of a species. Recent studies of Acacia senegal report diploids and occasional tetraploids in the Sudano-Sahelian region of sub-Saharan Africa, but nothing is known about the overall extent of DNA ploidy variation within the species. In this study, we determine the DNA content and ploidy level of A. senegal across its native range, and explore whether the variation is related to its evolutionary and colonization history. We used propidium iodide flow cytometry (FCM) to estimate DNA content (2C value) and infer ploidy in 157 individuals from 54 populations on various tissues, using seeds, fresh leaves, dried leaves and twigs and herbarium specimens. The mean 2C DNA (pg ± s.d.) contents detected were 1.47 ± 0.09, 2.12 ± 0.02, 2.89 ± 0.12, and a single individual with 4.51 pg, corresponding to a polyploid series of diploid, triploid, tetraploid and hexaploid individuals. Diploids were confirmed by chromosome counts (2n = 2x = 26). Most populations (90.7 %) were of single ploidy level, while mixed ploidy populations (9.3 %) comprising mostly diploids (2x+3x, 2x+4x and 2x+6x) were restricted to the Sudano-Sahelian and Indian subcontinent regions, its northern range. The species is predominantly diploid, and no mixed ploidy populations were detected in east and southern Africa, its southern range. The geographic pattern of ploidy variation in conjunction with existing phylogeographic and phylogenetic data of the species suggests that polyploids have occurred multiple times in its evolutionary and recent colonization history, including contemporary ecological timescales. The successful use of external tissues of dried twigs in FCM is new, and presents the opportunity to study numerous other dryland woody species.

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