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1.
mSystems ; 9(5): e0025024, 2024 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-38564716

RESUMO

Most biosynthetic gene clusters (BGC) encoding the synthesis of important microbial secondary metabolites, such as antibiotics, are either silent or poorly expressed; therefore, to ensure a strong pipeline of novel antibiotics, there is a need to develop rapid and efficient strain development approaches. This study uses comparative genome analysis to instruct rational strain improvement, using Streptomyces rimosus, the producer of the important antibiotic oxytetracycline (OTC) as a model system. Sequencing of the genomes of two industrial strains M4018 and R6-500, developed independently from a common ancestor, identified large DNA rearrangements located at the chromosome end. We evaluated the effect of these genome deletions on the parental S. rimosus Type Strain (ATCC 10970) genome where introduction of a 145 kb deletion close to the OTC BGC in the Type Strain resulted in massive OTC overproduction, achieving titers that were equivalent to M4018 and R6-500. Transcriptome data supported the hypothesis that the reason for such an increase in OTC biosynthesis was due to enhanced transcription of the OTC BGC and not due to enhanced substrate supply. We also observed changes in the expression of other cryptic BGCs; some metabolites, undetectable in ATCC 10970, were now produced at high titers. This study demonstrated for the first time that the main force behind BGC overexpression is genome rearrangement. This new approach demonstrates great potential to activate cryptic gene clusters of yet unexplored natural products of medical and industrial value.IMPORTANCEThere is a critical need to develop novel antibiotics to combat antimicrobial resistance. Streptomyces species are very rich source of antibiotics, typically encoding 20-60 biosynthetic gene clusters (BGCs). However, under laboratory conditions, most are either silent or poorly expressed so that their products are only detectable at nanogram quantities, which hampers drug development efforts. To address this subject, we used comparative genome analysis of industrial Streptomyces rimosus strains producing high titers of a broad spectrum antibiotic oxytetracycline (OTC), developed during decades of industrial strain improvement. Interestingly, large-scale chromosomal deletions were observed. Based on this information, we carried out targeted genome deletions in the native strain S. rimosus ATCC 10970, and we show that a targeted deletion in the vicinity of the OTC BGC significantly induced expression of the OTC BGC, as well as some other silent BGCs, thus suggesting that this approach may be a useful way to identify new natural products.


Assuntos
Antibacterianos , Genoma Bacteriano , Família Multigênica , Oxitetraciclina , Streptomyces rimosus , Oxitetraciclina/biossíntese , Streptomyces rimosus/genética , Streptomyces rimosus/metabolismo , Antibacterianos/biossíntese , Família Multigênica/genética , Streptomyces/genética , Streptomyces/metabolismo , Streptomyces/efeitos dos fármacos
2.
Elife ; 122024 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-38193543

RESUMO

Developing neural circuits are influenced by activity and are especially sensitive to changes in activity during critical periods (CPs) of development. Changes occurring during a CP often become 'locked in' so that they affect the mature network. Indeed, several neurodevelopmental disorders have been linked to excessive activity during such periods. It is, therefore, important to identify those aspects of neural circuit development that are influenced by neural activity during a CP. In this study, we take advantage of the genetic tractability of Drosophila to show that activity perturbation during an embryonic CP permanently alters properties of the locomotor circuit. Specific changes we identify include increased synchronicity of motoneuron activity and greater strengthening of excitatory over inhibitory synaptic drive to motoneurons. These changes are sufficient to reduce network robustness, evidenced by increased sensitivity to induced seizure. We also show that we can rescue these changes when increased activity is mitigated by inhibition provided by mechanosensory neurons. Similarly, we demonstrate a dose-dependent relationship between inhibition experienced during the CP and the extent to which it is possible to rescue the hyperexcitable phenotype characteristic of the parabss mutation. This suggests that developing circuits must be exposed to a properly balanced sum of excitation and inhibition during the CP to achieve normal mature network function. Our results, therefore, provide novel insight into how activity during a CP shapes specific elements of a circuit, and how activity during this period is integrated to tune neural circuits to the environment in which they will likely function.


Assuntos
Drosophila , Transtornos do Neurodesenvolvimento , Animais , Inibição Psicológica , Neurônios Motores , Mutação
3.
J Theor Biol ; 576: 111649, 2024 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-37866716

RESUMO

Natural movement is clearly related to health, however, it is also highly complex and difficult to measure. Most attempts to measure it focus on functional movements in humans, and while this a valid and popular approach, assays focussed on particular movements cannot capture the range of natural movement that occurs outside them. It is also difficult to use current techniques to compare movement across animal species. Interspecies comparison may be useful for identifying conserved biomechanical and/ or computational principles of movement that could inform human and veterinary medicine, plus several other fields of research. It is therefore important that research develops a system for quantifying movement in freely moving animals in natural environments and relating it to length and quality of life (LQOL). The present text proposes a novel theoretical framework for doing so, based on screening movement ability (MA). MA is calculated from three major variables - Movement Quality, Movement Complexity, and Movement Quantity. These may represent the most important components of movement as it relates to LQOL, and offer insight into how and why differences in the relationship between movement and LQOL occur. A constrained version of the framework is validated in Drosophila, which suggests that MA may indeed represent a useful new paradigm for understanding the relationship between movement and length and quality of life.


Assuntos
Movimento , Qualidade de Vida , Animais , Humanos , Meio Ambiente
4.
Clin Transl Radiat Oncol ; 39: 100580, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36686563

RESUMO

Background and purpose: The use of external beam radiotherapy (EBRT) and contact X-Ray brachytherapy (CXB) is emerging as an effective alternative in patients with early stage rectal cancer with the intent of organ preservation (OP). Short course radiotherapy (SCRT) is an alternative EBRT schedule for patients not fit for chemotherapy or for longer courses of EBRT. There are no multicentre studies that have reported on the outcomes of SCRT with a CXB boost, therefore we present these from patients from centres from the UK and Sweden. Materials and methods: From the Guildford Colorectal Database or local databases, 258 patients who underwent SCRT and CXB with the intent of OP from five centres treated between 2007 and 2019 were identified. Response and survival data was analysed and presented. Results: With a median age of 81, 226 patients were treated with radiotherapy alone (RTA) and 32 immediately after local excision (ILE). Median follow-up was 24 months. 70% and 97% of patients in the RTA and ILE groups respectively had a complete clinical response (cCR) after SCRT with CXB. Of those, local relapse was seen in 16% of the RTA and 3% of the ILE group. Median survival was 40 months after CXB in the RTA and 52 months in the ILE group. 94% of patients remained stoma-free to the point of latest follow-up. Conclusion: This data suggests that CXB when combined with SCRT, in a mainly elderly and comorbid population, provides good palliation with stoma-avoidance. Oncological outcomes compare with previously published work. A greater focus is required on quality of life outcomes after OP.

5.
Front Physiol ; 13: 1073307, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36531164

RESUMO

Critical periods are phases of heightened plasticity that occur during the development of neural networks. Beginning with pioneering work of Hubel and Wiesel, which identified a critical period for the formation of ocular dominance in mammalian visual network connectivity, critical periods have been identified for many circuits, both sensory and motor, and across phyla, suggesting a universal phenomenon. However, a key unanswered question remains why these forms of plasticity are restricted to specific developmental periods rather than being continuously present. The consequence of this temporal restriction is that activity perturbations during critical periods can have lasting and significant functional consequences for mature neural networks. From a developmental perspective, critical period plasticity might enable reproducibly robust network function to emerge from ensembles of cells, whose properties are necessarily variable and fluctuating. Critical periods also offer significant clinical opportunity. Imposed activity perturbation during these periods has shown remarkable beneficial outcomes in a range of animal models of neurological disease including epilepsy. In this review, we spotlight the recent identification of a locomotor critical period in Drosophila larva and describe how studying this model organism, because of its simplified nervous system and an almost complete wired connectome, offers an attractive prospect of understanding how activity during a critical period impacts a neuronal network.

6.
ACS Infect Dis ; 8(12): 2552-2563, 2022 12 09.
Artigo em Inglês | MEDLINE | ID: mdl-36444998

RESUMO

MGB-BP-3 is a potential first-in-class antibiotic, a Strathclyde Minor Groove Binder (S-MGB), that has successfully completed Phase IIa clinical trials for the treatment of Clostridioides difficile associated disease. Its precise mechanism of action and the origin of limited activity against Gram-negative pathogens are relatively unknown. Herein, treatment with MGB-BP-3 alone significantly inhibited the bacterial growth of the Gram-positive, but not Gram-negative, bacteria as expected. Synergy assays revealed that inefficient intracellular accumulation, through both permeation and efflux, is the likely reason for lack of Gram-negative activity. MGB-BP-3 has strong interactions with its intracellular target, DNA, in both Gram-negative and Gram-positive bacteria, revealed through ultraviolet-visible (UV-vis) thermal melting and fluorescence intercalator displacement assays. MGB-BP-3 was confirmed to bind to dsDNA as a dimer using nano-electrospray ionization mass spectrometry and nuclear magnetic resonance (NMR) spectroscopy. Type II bacterial topoisomerase inhibition assays revealed that MGB-BP-3 was able to interfere with the supercoiling action of gyrase and the relaxation and decatenation actions of topoisomerase IV of both Staphylococcus aureus and Escherichia coli. However, no evidence of stabilization of the cleavage complexes was observed, such as for fluoroquinolones, confirmed by a lack of induction of DSBs and the SOS response in E. coli reporter strains. These results highlight additional mechanisms of action of MGB-BP-3, including interference of the action of type II bacterial topoisomerases. While MGB-BP-3's lack of Gram-negative activity was confirmed, and an understanding of this presented, the recognition that MGB-BP-3 can target DNA of Gram-negative organisms will enable further iterations of design to achieve a Gram-negative active S-MGB.


Assuntos
Escherichia coli
7.
mSystems ; 7(5): e0019922, 2022 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-36094082

RESUMO

Streptomyces rimosus is an industrial streptomycete, best known as a producer of oxytetracycline, one of the most widely used antibiotics. Despite the significant contribution of Streptomyces species to the pharmaceutical industry, most omics analyses have only been conducted on the model organism Streptomyces coelicolor. In recent years, protein phosphorylation on serine, threonine, and tyrosine (Ser, Thr, and Tyr, respectively) has been shown to play a crucial role in the regulation of numerous cellular processes, including metabolic changes leading to antibiotic production and morphological changes. In this study, we performed a comprehensive quantitative (phospho)proteomic analysis during the growth of S. rimosus under conditions of oxytetracycline production and pellet fragmentation. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis combined with phosphopeptide enrichment detected a total of 3,725 proteins, corresponding to 45.6% of the proteome and 417 phosphorylation sites from 230 phosphoproteins. Significant changes in abundance during three distinct growth phases were determined for 494 proteins and 98 phosphorylation sites. Functional analysis revealed changes in phosphorylation events of proteins involved in important cellular processes, including regulatory mechanisms, primary and secondary metabolism, cell division, and stress response. About 80% of the phosphoproteins detected during submerged growth of S. rimosus have not yet been reported in streptomycetes, and 55 phosphoproteins were not reported in any prokaryote studied so far. This enabled the creation of a unique resource that provides novel insights into the dynamics of (phospho)proteins and reveals many potential regulatory events during antibiotic production in liquid culture of an industrially important bacterium. IMPORTANCE Streptomyces rimosus is best known as a primary source of oxytetracycline (OTC). The significant global market value of OTC highlights the need for a better understanding of the regulatory mechanisms that lead to production of this antibiotic. Our study provides, for the first time, a detailed insight into the dynamics of (phospho)proteomic profiles during growth and antibiotic production in liquid culture of S. rimosus. Significant changes in protein synthesis and phosphorylation have been revealed for a number of important cellular proteins during the growth stages that coincide with OTC production and morphological changes of this industrially important bacterium. Most of these proteins have not been detected in previous studies. Therefore, our results significantly expand the insight into phosphorylation events associated with important cellular processes and antibiotic production; they also greatly increase the phosphoproteome of streptomycetes and contribute with newly discovered phosphoproteins to the database of prokaryotic phosphoproteomes. This can consequently lead to the design of novel research directions in elucidation of the complex regulatory network in Streptomyces.


Assuntos
Oxitetraciclina , Streptomyces rimosus , Streptomyces , Antibacterianos/metabolismo , Streptomyces rimosus/metabolismo , Proteoma/análise , Proteômica , Cromatografia Líquida , Espectrometria de Massas em Tandem , Fosfoproteínas/análise
8.
J Neurosci ; 2022 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-35868863

RESUMO

The Drosophila connectome project aims to map the synaptic connectivity of entire larval and adult fly neural networks, which is essential for understanding nervous system development and function. So far, the project has produced an impressive amount of electron microscopy data that has facilitated reconstructions of specific synapses, including many in the larval locomotor circuit. While this breakthrough represents a technical tour-de-force, the data remain under-utilised, partly due to a lack of functional validation of reconstructions. Attempts to validate connectivity posited by the connectome project, have mostly relied on behavioural assays and/or GRASP or GCaMP imaging. While these techniques are useful, they have limited spatial or temporal resolution. Electrophysiological assays of synaptic connectivity overcome these limitations. Here, we combine patch clamp recordings with optogenetic stimulation in male and female larvae, to test synaptic connectivity proposed by connectome reconstructions. Specifically, we use multiple driver lines to confirm that several connections between premotor interneurons and the anterior corner cell (aCC) motoneuron are, as the connectome project suggests, monosynaptic. In contrast, our results also show that conclusions based on GRASP imaging may provide false positive results regarding connectivity between cells. We also present a novel imaging tool, based on the same technology as our electrophysiology, as a favourable alternative to GRASP. Finally, of eight Gal4 lines tested, five are reliably expressed in the premotors they are targeted to. Thus, our work highlights the need to confirm functional synaptic connectivity, driver line specificity, and use of appropriate genetic tools to support connectome projects.SIGNIFICANCE STATEMENTThe Drosophila connectome project aims to provide a complete description of connectivity between neurons in an organism that presents experimental advantages over other models. It has reconstructed over 80 percent of the fly larva's synaptic connections by manual identification of anatomical landmarks present in serial section transmission electron microscopy (ssTEM) volumes of the larval CNS. We use a highly reliable electrophysiological approach to verify these connections, so provide useful insight into the accuracy of work based on ssTEM. We also present a novel imaging tool for validating excitatory monosynaptic connections between cells, and show that several genetic driver lines designed to target neurons of the larval connectome exhibit non-specific and/or unreliable expression.

9.
Future Drug Discov ; 4(1): FDD73, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35600289

RESUMO

The standard drug discovery paradigm of single molecule - single biological target - single biological effect is perhaps particularly unsuitable for anti-infective drug discovery. This is due to the rapid evolution of resistance likely to be observed with single target drugs. Multitargeted anti-infective drugs are likely to be superior due to their lower susceptibility to target-related resistance mechanisms. Strathclyde minor groove binders are a class of compounds which have been developed by adopting the multitargeted anti-infective drugs paradigm, and their effectiveness against a wide range of pathogenic organisms is discussed. The renaming of this class to Strathclyde nucleic acid binders is also presented due to their likely targets including both DNA and RNA.

10.
J Sports Sci Med ; 21(1): 127-130, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35250342

RESUMO

Road-racing shoes recently experienced major changes. In the recent past, lightweight, thin midsole shoes were thought to help runners maximize their performance. But, in 2017, Nike released the Vaporfly shoe which transformed the thinking about racing shoe design. Incorporating a curved carbon fiber plate embedded in a thick, compliant and resilient midsole resulted in a reduced metabolic cost across a range of running speeds. We hypothesized the new style of shoes would be less effective uphill than downhill due to the larger ground reaction forces and hence greater elastic energy storage in the shoe during downhill running. Eighteen runners completed two days of testing, each comprising two trials of two shoe models (Saucony Endorphin Pro (EP) and Type A) and three grade conditions (uphill, level and downhill), i.e. 12 trials per day. Oxygen uptake, ground reaction forces, and lower-body kinematics were captured during each condition. Comparisons of the percent metabolic benefit were made between shoes for each grade. Stride rate, ground time, peak vertical force, and flight time were regressed with the percent metabolic benefit of the EP over the Type A shoe across grades. Metabolic benefits of the Endorphin Pro were similar across the three grade conditions (p = 0.778). No significant correlations were observed between how much benefit one runner got over another specific to grade. The new style of road-racing shoes effectively decreases metabolic cost equally across grades. Differences in running mechanics between runners did not explain greater individual metabolic benefits between shoe conditions during uphill or downhill running.


Assuntos
Endorfinas , Corrida , Fenômenos Biomecânicos , Fibra de Carbono , Humanos , Sapatos
11.
J Sports Sci Med ; 21(1): 120-126, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35250341

RESUMO

The abdominal muscles are vital in providing core stability for functional movements during most activities. There is a correlation between side asymmetry of these muscles and dysfunction. Thus, the purpose of this study was to evaluate and compare trunk muscle morphology and trunk rotational strength between sprint hurdlers, an asymmetrical sport, and sprinters, a symmetrical sport. Twenty-one trained collegiate sprint hurdlers and sprinters were recruited for the study (Hurdlers: 4M, 7F; Sprinters: 8M, 2F), average age (years) hurdlers: 20 ± 1.2; sprinters: 20.4 ± 1.9, height (cm) hurdlers: 172.6 ± 10.2; sprinters: 181.7 ± 4.5, and weight (kg) hurdlers: 67.6 ± 12.0; sprinters: 73.9 ± 5.6. Using real-time ultrasound, panoramic images of the internal oblique (IO) and external oblique (EO) were obtained at rest and contracted (flexion and rotation) in a seated position for both right and left sides of the trunk. While wearing a specially crafted shoulder harness, participants performed three maximal voluntary trunk rotational contractions (MVC). The three attempts were then averaged to obtain an overall MVC score for trunk rotation strength. Average MVC trunk rotational strength to the right was greater among all participants, p < 0.001. The IO showed greater and significant thickness changes from resting to contracted state than the EO, this was observed in all participants. The IO side asymmetry was significantly different between groups p < 0.01. Hurdlers, involved in a unilaterally demanding sport, exhibited the expected asymmetry in muscle morphology and in trunk rotational strength. Interestingly, sprinters, although involved in a seemingly symmetrical sport, also exhibited asymmetrical trunk morphology and trunk rotational strength.


Assuntos
Músculos Abdominais , Músculos Abdominais Oblíquos , Músculos Abdominais/diagnóstico por imagem , Músculos Abdominais/fisiologia , Estudos Transversais , Humanos , Músculo Esquelético/fisiologia , Tronco/fisiologia
12.
Microb Genom ; 7(11)2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34779763

RESUMO

Here, we characterize an uncommon set of telomeres from Streptomyces rimosus ATCC 10970, the parental strain of a lineage of one of the earliest-discovered antibiotic producers. Following the closure of its genome sequence, we compared unusual telomeres from this organism with the other five classes of replicon ends found amongst streptomycetes. Closed replicons of streptomycete chromosomes were organized with respect to their phylogeny and physical orientation, which demonstrated that different telomeres were not associated with particular clades and are likely shared amongst different strains by plasmid-driven horizontal gene transfer. Furthermore, we identified a ~50 kb origin island with conserved synteny that is located at the core of all streptomycete chromosomes and forms an axis around which symmetrical chromosome inversions can take place. Despite this chromosomal bilateral symmetry, a bias in parS sites to the right of oriC is maintained across the family Streptomycetaceae and suggests that the formation of ParB/parS nucleoprotein complexes on the right replichore is a conserved feature in streptomycetes. Consequently, our studies reveal novel features of linear bacterial replicons that, through their manipulation, may lead to improvements in growth and productivity of this important industrial group of bacteria.


Assuntos
Cromossomos Bacterianos , Replicon , Bactérias/genética , Cromossomos Bacterianos/genética , Plasmídeos/genética , Replicon/genética
13.
Medicina (Kaunas) ; 57(9)2021 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-34577785

RESUMO

Background and Objectives: Blood flow restriction during low-load exercise stimulates similar muscle adaptations to those normally observed with higher loads. Differences in the arterial occlusion pressure (AOP) between limbs and between sexes are unclear. We compared the AOP of the superficial femoral artery in the dominant and non-dominant legs, and the relationship between blood flow and occlusion pressure in 35 (16 males, 19 females) young adults. Materials and Methods: Using ultrasound, we measured the AOP of the superficial femoral artery in both legs. Blood flow at occlusion pressures ranging from 0% to 100% of the AOP was measured in the dominant leg. Results: There was a significant difference in the AOP between males and females in the dominant (230 ± 41 vs. 191 ± 27 mmHg; p = 0.002) and non-dominant (209 ± 37 vs. 178 ± 21 mmHg; p = 0.004) legs, and between the dominant and non-dominant legs in males (230 ± 41 vs. 209 ± 37 mmHg; p = 0.009) but not females (191 ± 27 vs. 178 ± 21 mmHg; p = 0.053), respectively. Leg circumference was the most influential independent predictor of the AOP. There was a linear relationship between blood flow (expressed as a percentage of unoccluded blood flow) and occlusion pressure (expressed as a percentage of AOP). Conclusions: Arterial occlusion pressure is not always greater in the dominant leg or the larger leg. Practitioners should measure AOP in both limbs to determine if occlusion pressures used during exercise should be limb specific. Occlusion pressures used during blood flow restriction exercise should be chosen carefully.


Assuntos
Artéria Femoral , Perna (Membro) , Pressão Sanguínea , Exercício Físico , Feminino , Artéria Femoral/diagnóstico por imagem , Humanos , Perna (Membro)/diagnóstico por imagem , Masculino , Músculo Esquelético , Fluxo Sanguíneo Regional , Adulto Jovem
14.
J Musculoskelet Neuronal Interact ; 21(3): 373-378, 2021 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-34465676

RESUMO

OBJECTIVES: To determine if a change in vertical jump performance from acute whole-body vibration can be explained by indirectly assessing spindle sensitivity from electromechanical delay. METHODS: Using a counter-balanced design, twenty college-aged participants performed whole-body vibration (WBV) and control treatments. WBV included 10 intervals (26 Hz, 3.6 mm) of 60 s in a half-squat followed by 60 s of rest. After 5 intervals, participants rested for 6-minutes before commencing the final 5 intervals. For the control, the exact same protocol of whole-body vibration was performed but without vibration. Electromechanical delay and vertical jump were assessed at baseline, during the 6-minute rest period and immediately after whole-body vibration and control. RESULTS: There were no differences between treatments, for both electromechanical delay (F(2, 38)=1.385, p=0.263) and vertical jump (F(2, 38)=0.040, p<0.96). Whole-body vibration had no effect on vertical jump performance. CONCLUSION: The current whole-body vibration protocol is not effective for acute vertical jump or electromechanical delay enhancement. Also, since there was no effect on electromechanical delay, this suggests that whole-body vibration did not enhance muscle spindle sensitivity for the parameters examined.


Assuntos
Força Muscular , Vibração , Humanos , Músculo Esquelético , Modalidades de Fisioterapia , Postura , Universidades , Vibração/uso terapêutico , Adulto Jovem
15.
Biol Open ; 10(10)2021 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-34553759

RESUMO

Ciliary motility is powered by a suite of highly conserved axoneme-specific dynein motor complexes. In humans, the impairment of these motors through mutation results in the disease primary ciliary dyskinesia (PCD). Studies in Drosophila have helped to validate several PCD genes whose products are required for cytoplasmic pre-assembly of axonemal dynein motors. Here we report the characterisation of the Drosophila orthologue of the less-known assembly factor DNAAF3. This gene, CG17669 (Dnaaf3), is expressed exclusively in developing mechanosensory chordotonal (Ch) neurons and the cells that generate spermatozoa, The only two Drosophila cell types bearing cilia/flagella containing dynein motors. Mutation of Dnaaf3 results in larvae that are deaf and adults that are uncoordinated, indicating defective Ch neuron function. The mutant Ch neuron cilia of the antenna specifically lack dynein arms, while Ca imaging in larvae reveals a complete loss of Ch neuron response to vibration stimulus, confirming that mechanotransduction relies on ciliary dynein motors. Mutant males are infertile with immotile sperm whose flagella lack dynein arms and show axoneme disruption. Analysis of proteomic changes suggest a reduction in heavy chains of all axonemal dynein forms, consistent with an impairment of dynein pre-assembly.


Assuntos
Dineínas do Axonema/genética , Transtornos da Motilidade Ciliar/genética , Proteínas de Drosophila/genética , Drosophila/genética , Proteínas Associadas aos Microtúbulos/genética , Animais , Axonema/genética , Cílios/genética , Feminino , Flagelos/genética , Masculino , Mecanotransdução Celular/genética , Mutação
16.
Front Neural Circuits ; 15: 684969, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34276315

RESUMO

It is difficult to answer important questions in neuroscience, such as: "how do neural circuits generate behaviour?," because research is limited by the complexity and inaccessibility of the mammalian nervous system. Invertebrate model organisms offer simpler networks that are easier to manipulate. As a result, much of what we know about the development of neural circuits is derived from work in crustaceans, nematode worms and arguably most of all, the fruit fly, Drosophila melanogaster. This review aims to demonstrate the utility of the Drosophila larval locomotor network as a model circuit, to those who do not usually use the fly in their work. This utility is explored first by discussion of the relatively complete connectome associated with one identified interneuron of the locomotor circuit, A27h, and relating it to similar circuits in mammals. Next, it is developed by examining its application to study two important areas of neuroscience research: critical periods of development and interindividual variability in neural circuits. In summary, this article highlights the potential to use the larval locomotor network as a "generic" model circuit, to provide insight into mammalian circuit development and function.


Assuntos
Encéfalo/crescimento & desenvolvimento , Drosophila melanogaster/crescimento & desenvolvimento , Larva/crescimento & desenvolvimento , Locomoção/fisiologia , Rede Nervosa/crescimento & desenvolvimento , Animais , Conectoma/métodos , Humanos
17.
Radiother Oncol ; 162: 195-201, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34329654

RESUMO

INTRODUCTION: Early rectal cancers are increasingly diagnosed through screening programmes and are often treated using local excision (LE). In the case of adverse pathological features completion total mesorectal excision surgery (TME) is the standard recommendation. The morbidity and mortality risks of TME have stimulated the use of adjunctive treatments following LE to achieve organ preservation. MATERIAL AND METHODS: Patients treated with adjuvant CXB following local excision between 2004 and 2017 in three centres were identified (Clatterbridge, Hull, Nice). All patients had adverse pathological features including: lymphovacular invasion, Sm2-3 Kikuchi level, tumour budding, pT2, positive resection margins (R1). CXB was performed with the Papillon50 tm machine to a dose of 40-60 Gy in 2 or 3 fractions over 2-4 weeks preceding/following external beam chemo/radiotherapy. Kaplan Meier survival estimates were used for outcomes measures. RESULTS: 194 patients were identified. Median age was 70 years. pT staging was: pT1:143, pT2:45, pT3:6. CXB alone was given in 24 pts and combined with EBRT in 170. Median follow-up time was 77 months (range 7-122 months). Local relapse rate was 8% and distant metastases 9%. Organ preservation was achieved in 95%. 6 year local recurrence free and overall survival was 91% and 81% respectively. Cancer specific survival was 97%. No treatment related mortality was seen. CONCLUSION: This large multi-centre cohort study using adjuvant CXB following local excision suggests excellent oncological outcomes for these patients without completion TME. This treatment approach can be considered as an alternative for selective patients compliant with long term follow up.


Assuntos
Braquiterapia , Neoplasias Retais , Idoso , Estudos de Coortes , Humanos , Recidiva Local de Neoplasia/patologia , Estadiamento de Neoplasias , Neoplasias Retais/patologia , Neoplasias Retais/radioterapia , Neoplasias Retais/cirurgia , Resultado do Tratamento , Raios X
18.
J Dance Med Sci ; 25(1): 30-37, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33706853

RESUMO

Irish dance has evolved in aesthetics that lead to greater physical demands on dancers' bodies. Irish dancers must land from difficult moves without letting their knees bend or heels touch the ground, causing large forces to be absorbed by the body. The majority of injuries incurred by Irish dancers are due to overuse (79.6%). The purpose of this study was to determine loads on the body of female Irish dancers, including peak force, rise rate of force, and impulse, in eight common Irish hard shoe and soft shoe dance movements. It was hypothesized that these movements would produce different ground reac- tion force (GRF) characteristics. Sixteen female Irish dancers were recruited from the three highest competitive levels. Each performed a warm-up, reviewed the eight movements, and then performed each movement three times on a force plate, four in soft shoes and four in hard shoes. Ground reaction forces were measured using a three-dimensional force plate recording at 1,000 Hz. Peak force, rise rate, and vertical impulse were calculated. Peak forces normalized by each dancer's body weight for each of these variables were significantly different between move- ments and shoe types [F(15, 15)= 65.4, p < 0.01; F(15, 15) = 65.0, p < 0.01; and F(15, 15) = 67.4, p < 0.01, respectively]. The variable years of experience was not correlated with peak force, rise rate, or impulse (p > 0.40). It is concluded that there was a large range in GRF characteristics among the eight movements studied. Understanding the force of each dance step will allow instructors to develop training routines that help dancers adapt gradually to the high forces experienced in Irish dance training and competitions, thereby limiting the potential for overuse injuries.


Assuntos
Transtornos Traumáticos Cumulativos , Dança , Peso Corporal , Transtornos Traumáticos Cumulativos/prevenção & controle , Feminino , Humanos , Movimento , Sapatos
19.
Microb Genom ; 7(1)2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33433310

RESUMO

Actinobacteria is a large and diverse phylum of bacteria that contains medically and ecologically relevant organisms. Many members are valuable sources of bioactive natural products and chemical precursors that are exploited in the clinic and made using the enzyme pathways encoded in their complex genomes. Whilst the number of sequenced genomes has increased rapidly in the last 20 years, the large size, complexity and high G+C content of many actinobacterial genomes means that the sequences remain incomplete and consist of large numbers of contigs with poor annotation, which hinders large-scale comparative genomic and evolutionary studies. To enable greater understanding and exploitation of actinobacterial genomes, specialized genomic databases must be linked to high-quality genome sequences. Here, we provide a curated database of 612 high-quality actinobacterial genomes from 80 genera, chosen to represent a broad phylogenetic group with equivalent genome re-annotation. Utilizing this database will provide researchers with a framework for evolutionary and metabolic studies, to enable a foundation for genome and metabolic engineering, to facilitate discovery of novel bioactive therapeutics and studies on gene family evolution. This article contains data hosted by Microreact.


Assuntos
Actinobacteria/genética , Actinobacteria/classificação , Composição de Bases , Curadoria de Dados , Bases de Dados Genéticas , Evolução Molecular , Genoma Bacteriano , Anotação de Sequência Molecular , Filogenia
20.
Phys Ther Sport ; 47: 114-119, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33249366

RESUMO

AIMS: To examine single bout and season long Achilles tendon cross-sectional area (CSA) changes before and after running during the early and late cross-country season. DESIGN: OBSERVATIONAL: repeated measures design study. SETTING: Controlled laboratory setting. PARTICIPANTS: This study consisted of 35 participants. The running group included 11 males and 9 females, the control group was 8 males and 7 females. MAIN OUTCOME MEASURES: Diagnostic ultrasound images were taken before and after runners completed a common recovery run during the early and late cross-country season. Ultrasound images of control participants, who did not run, were taken following an averaged time that athletes spent running. RESULTS: No significant tendon season long CSA increases occurred for runners (p = 0.453). Runners experienced significant Achilles tendon CSA decreases compared within subjects (p < 0.05) and between controls (p < 0.05). Significant CSA decreases occurred for runners during the early and late season run (p < 0.05) with greater percentages of decrease in the early season (p = 0.009). Male and female runners experienced similar CSA decreases while running (p = 0.696). CONCLUSIONS: No Achilles tendon CSA increases occurred over the season. Significant Achilles tendon CSA decreases occurred while running during early and late season runs, but varied with larger CSA decreases occurring during the early season.


Assuntos
Tendão do Calcâneo/anatomia & histologia , Tendão do Calcâneo/fisiologia , Adaptação Fisiológica , Comportamento Competitivo/fisiologia , Corrida/fisiologia , Tendão do Calcâneo/diagnóstico por imagem , Tendão do Calcâneo/lesões , Adulto , Feminino , Humanos , Masculino , Estações do Ano , Ultrassonografia , Universidades , Adulto Jovem
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