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1.
Bone Joint J ; 106-B(5 Supple B): 133-138, 2024 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-38688506

RESUMEN

Aims: Dual-mobility acetabular components (DMCs) have improved total hip arthroplasty (THA) stability in femoral neck fractures (FNFs). In osteoarthritis, the direct anterior approach (DAA) has been promoted for improving early functional results compared with the posterolateral approach (PLA). The aim of this study was to compare these two approaches in FNF using DMC-THA. Methods: A prospective continuous cohort study was conducted on patients undergoing operation for FNF using DMC by DAA or PLA. Functional outcome was evaluated using the Harris Hip Score (HHS) and Parker score at three months and one year. Perioperative complications were recorded, and radiological component positioning evaluated. Results: There were 50 patients in the DAA group and 54 in the PLA group. The mean HHS was 85.5 (SD 8.8) for the DAA group and 81.8 (SD 11.9) for the PLA group (p = 0.064). In all, 35 patients in the DAA group and 40 in the PLA group returned to their pre-fracture Parker score (p = 0.641) in both groups. No statistically significant differences between groups were found at one year regarding these two scores (p = 0.062 and p = 0.723, respectively). The DAA was associated with more intraoperative complications (p = 0.013). There was one dislocation in each group, and four revisions for DAA and one for PLA, but this difference was not statistically significant. There were also no significant differences regarding blood loss, length of stay, or operating time. Conclusion: In DMC-THA for FNF, DAA did not achieve better functional results than PLA, either at three months or at one year. Moreover, DAA presented an increased risk of intra-operative complications.


Asunto(s)
Acetábulo , Artroplastia de Reemplazo de Cadera , Fracturas del Cuello Femoral , Humanos , Artroplastia de Reemplazo de Cadera/métodos , Masculino , Femenino , Fracturas del Cuello Femoral/cirugía , Anciano , Estudios Prospectivos , Persona de Mediana Edad , Acetábulo/cirugía , Acetábulo/lesiones , Prótesis de Cadera , Resultado del Tratamiento , Anciano de 80 o más Años , Complicaciones Posoperatorias/etiología , Diseño de Prótesis
2.
Bone Joint J ; 106-B(3): 224-226, 2024 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-38423116
3.
Plant Divers ; 46(1): 144-148, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38343589

RESUMEN

•The first reported mitochondrial genome (Cinnamomum chekiangense) of the Lauraceae family.•The mitogenome of C. chekiangense retains almost all of the ancestral protein-coding genes and has the highest RNA editing number in angiosperms.•Both of the plastid and mitochondrial phylogenetic trees support the magnoliids as a sister group of monocots and eudicots.

4.
Med Sci Sports Exerc ; 56(6): 1066-1076, 2024 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-38233993

RESUMEN

INTRODUCTION: Early life growth restriction significantly increases the risk of adulthood physical inactivity and thereby chronic disease incidence. Improvements in motor skill acquisition could result in greater physical activity engagement in the growth-restricted population, thus reducing chronic disease risk. The purpose of this study was to implement an early life motor training intervention to improve physical activity engagement in control and growth-restricted mice. METHODS: Mice were growth restricted in early life utilizing a validated nutritive model or remained fully nourished in early life as a control. All mice were tested throughout early life for various components of motor skill acquisition. On postnatal day 10, mice were randomly assigned to engage in an early life motor skill intervention daily until postnatal day 21 or remained as a sedentary control. All mice were given access to an in-cage running wheel from postnatal days 45-70. RESULTS: Growth-restricted group (PGR) mice had impaired trunk and postural control, coordination/vestibular development, and hindlimb strength in early life compared with control mice. There were no differences in wheel running behavior between the trained and sedentary mice, although control mice ran at a faster average speed compared with PGR mice. Control female mice ran more than PGR female mice during the week 2 dark cycle. CONCLUSIONS: Early life growth restriction reduced motor skill attainment throughout early life, which may be associated with reduced ability to engage in physical activity in adulthood. The early life motor skill intervention did not elicit changes in body weight or physical activity engagement in control or PGR mice, indicating that a more intense/different intervention specifically targeting skeletal muscle may be necessary to counteract the detrimental effects of early life growth restriction.


Asunto(s)
Destreza Motora , Condicionamiento Físico Animal , Animales , Destreza Motora/fisiología , Femenino , Condicionamiento Físico Animal/fisiología , Masculino , Ratones , Equilibrio Postural/fisiología , Fuerza Muscular/fisiología , Ratones Endogámicos C57BL
5.
Exp Physiol ; 109(4): 562-575, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38180279

RESUMEN

Postnatal growth restriction (PGR) can increase the risk of cardiovascular disease (CVD) potentially due to impairments in oxidative phosphorylation (OxPhos) within cardiomyocyte mitochondria. The purpose of this investigation was to determine if PGR impairs cardiac metabolism, specifically OxPhos. FVB (Friend Virus B-type) mice were fed a normal-protein (NP: 20% protein), or low-protein (LP: 8% protein) isocaloric diet 2 weeks before mating. LP dams produce ∼20% less milk, and pups nursed by LP dams experience reduced growth into adulthood as compared to pups nursed by NP dams. At birth (PN1), pups born to dams fed the NP diet were transferred to LP dams (PGR group) or a different NP dam (control group: CON). At weaning (PN21), all mice were fed the NP diet. At PN22 and PN80, mitochondria were isolated for respirometry (oxygen consumption rate, J O 2 ${J_{{{\mathrm{O}}_{\mathrm{2}}}}}$ ) and fluorimetry (reactive oxygen species emission, J H 2 O 2 ${J_{{{\mathrm{H}}_{\mathrm{2}}}{{\mathrm{O}}_{\mathrm{2}}}}}$ ) analysis measured as baseline respiration (LEAK) and with saturating ADP (OxPhos). Western blotting at PN22 and PN80 determined protein abundance of uncoupling protein 3, peroxiredoxin-6, voltage-dependent anion channel and adenine nucleotide translocator 1 to provide further insight into mitochondrial function. ANOVAs with the main effects of diet, sex and age with α-level of 0.05 was set a priori. Overall, PGR (7.8 ± 1.1) had significant (P = 0.01) reductions in respiratory control in complex I when compared to CON (8.9 ± 1.0). In general, our results show that PGR led to higher electron leakage in the form of free radical production and reactive oxygen species emission. No significant diet effects were found in protein abundance. The observed reduced respiratory control and increased ROS emission in PGR mice may increase risk for CVD in mice.


Asunto(s)
Enfermedades Cardiovasculares , Mitocondrias Cardíacas , Animales , Ratones , Especies Reactivas de Oxígeno/metabolismo , Mitocondrias Cardíacas/metabolismo , Miocardio/metabolismo , Dieta con Restricción de Proteínas
6.
Bone Jt Open ; 5(1): 69-77, 2024 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-38269598

RESUMEN

Aims: The management of fractures of the medial epicondyle is one of the greatest controversies in paediatric fracture care, with uncertainty concerning the need for surgery. The British Society of Children's Orthopaedic Surgery prioritized this as their most important research question in paediatric trauma. This is the protocol for a randomized controlled, multicentre, prospective superiority trial of operative fixation versus nonoperative treatment for displaced medial epicondyle fractures: the Surgery or Cast of the EpicoNdyle in Children's Elbows (SCIENCE) trial. Methods: Children aged seven to 15 years old inclusive, who have sustained a displaced fracture of the medial epicondyle, are eligible to take part. Baseline function using the Patient-Reported Outcomes Measurement Information System (PROMIS) upper limb score, pain measured using the Wong Baker FACES pain scale, and quality of life (QoL) assessed with the EuroQol five-dimension questionnaire for younger patients (EQ-5D-Y) will be collected. Each patient will be randomly allocated (1:1, stratified using a minimization algorithm by centre and initial elbow dislocation status (i.e. dislocated or not-dislocated at presentation to the emergency department)) to either a regimen of the operative fixation or non-surgical treatment. Outcomes: At six weeks, and three, six, and 12 months, data on function, pain, sports/music participation, QoL, immobilization, and analgesia will be collected. These will also be repeated annually until the child reaches the age of 16 years. Four weeks after injury, the main outcomes plus data on complications, resource use, and school absence will be collected. The primary outcome is the PROMIS upper limb score at 12 months post-randomization. All data will be obtained through electronic questionnaires completed by the participants and/or parents/guardians. The NHS number of participants will be stored to enable future data linkage to sources of routinely collected data (i.e. Hospital Episode Statistics).

7.
Nat Commun ; 14(1): 8263, 2023 Dec 13.
Artículo en Inglés | MEDLINE | ID: mdl-38092766

RESUMEN

Gametogenesis in Plasmodium spp. occurs within the Anopheles mosquito and is essential for sexual reproduction / differentiation and onwards transmission to mammalian hosts. To better understand the 3D organisation of male gametogenesis, we used serial block face scanning electron microscopy (SBF-SEM) and serial-section cellular electron tomography (ssET) of P. berghei microgametocytes to examine key structures during male gamete formation. Our data reveals an elaborate organisation of axonemes coiling around the nucleus in opposite directions forming a central axonemal band in microgametocytes. Furthermore, we discover the nucleus of microgametes to be tightly coiled around the axoneme in a complex structure whose formation starts before microgamete emergence during exflagellation. Our discoveries of the detailed 3D organisation of the flagellated microgamete and the haploid genome highlight some of the atypical mechanisms of axoneme assembly and haploid genome organisation during male gamete formation in the malaria parasite.


Asunto(s)
Anopheles , Plasmodium berghei , Masculino , Animales , Plasmodium berghei/genética , Haploidia , Células Germinativas , Anopheles/parasitología , Flagelos/genética , Mamíferos
8.
J Anim Sci ; 1012023 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-37880833

RESUMEN

Heart disease is the leading cause of death in humans and evidence suggests early life growth-restriction increases heart disease risk in adulthood. Therefore, this study sought to investigate the effects of low birth weight (LBW) and postnatal restricted nutrition (RN) on cardiac function in neonatal pigs. We hypothesized that LBW and RN would reduce cardiac function in pigs but this effect would be reversed with refeeding. To investigate this hypothesis, pigs born weighing <1.5 kg were assigned LBW, and pigs born >1.5 kg were assigned normal birth weight (NBW). Half the LBW and NBW pigs underwent ~25% total nutrient restriction via intermittent suckling (assigned RN) for the first 4 wk post-farrowing. The other half of piglets were allowed unrestricted suckling access to the sow (assigned NN). At 28 d of age (weaning), pigs were weaned and provided ad libitum access to a standard diet. Echocardiographic, vascular ultrasound, and blood pressure (BP) measurements were performed on day 28 and again on day 56 to assess cardiovascular structure and function. A full factorial three-way ANOVA (NN vs. RN, LBW vs. NBW, male vs. female) was performed. Key findings include reduced diastolic BP (P = 0.0401) and passive ventricular filling (P = 0.0062) in RN pigs at 28 d but this was reversed after refeeding. LBW piglets have reduced cardiac output index (P = 0.0037) and diastolic and systolic wall thickness (P = 0.0293 and P = 0.0472) at 56 d. Therefore, cardiac dysfunction from RN is recovered with adequate refeeding while LBW programs irreversible cardiac dysfunction despite proper refeeding in neonatal pigs.


Heart disease is the leading cause of death in humans, and in addition to the known modifiable risk factors, evidence suggests early life undernutrition increases heart disease risk in adulthood. Specifically, low birth weight (LBW) has been linked to poor infant cardiac development which could be made worse by an inadequate postnatal diet. Globally, 160 million children under the age of five experience a poor nutritive environment leading to growth-restriction highlighting the need for continued research. Using a pig model, the present investigation examined the effects of LBW and a restricted diet during postnatal life on cardiac structure and function in preweaning and post-weaning piglets. The most important findings were (1) nutrient-restricted piglets had reduced cardiac function at 28 d old but refeeding reversed cardiac dysfunction at 56 d, indicating that nutrient-induced cardiac dysfunction can be reversed, and (2) LBW pigs presented with cardiac dysfunction at 56 d regardless of feeding level, suggesting potential for an increased risk of heart disease in adulthood with LBW.


Asunto(s)
Cardiopatías , Enfermedades de los Porcinos , Porcinos , Animales , Femenino , Masculino , Humanos , Recién Nacido , Peso al Nacer/fisiología , Recién Nacido de Bajo Peso/fisiología , Cardiopatías/veterinaria
9.
Nat Microbiol ; 8(11): 2154-2169, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37884813

RESUMEN

Malaria-associated pathogenesis such as parasite invasion, egress, host cell remodelling and antigenic variation requires concerted action by many proteins, but the molecular regulation is poorly understood. Here we have characterized an essential Plasmodium-specific Apicomplexan AP2 transcription factor in Plasmodium falciparum (PfAP2-P; pathogenesis) during the blood-stage development with two peaks of expression. An inducible knockout of gene function showed that PfAP2-P is essential for trophozoite development, and critical for var gene regulation, merozoite development and parasite egress. Chromatin immunoprecipitation sequencing data collected at timepoints matching the two peaks of pfap2-p expression demonstrate PfAP2-P binding to promoters of genes controlling trophozoite development, host cell remodelling, antigenic variation and pathogenicity. Single-cell RNA sequencing and fluorescence-activated cell sorting revealed de-repression of most var genes in Δpfap2-p parasites. Δpfap2-p parasites also overexpress early gametocyte marker genes, indicating a regulatory role in sexual stage conversion. We conclude that PfAP2-P is an essential upstream transcriptional regulator at two distinct stages of the intra-erythrocytic development cycle.


Asunto(s)
Malaria , Parásitos , Plasmodium , Animales , Malaria/parasitología , Regulación de la Expresión Génica , Plasmodium falciparum/genética
10.
Sports Med Health Sci ; 5(3): 205-212, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37753423

RESUMEN

Physical activity engagement results in a variety of positive health outcomes, including a reduction in cardiovascular disease risk partially due to eccentric remodeling of the heart. The purpose of this investigation was to determine if four replicate lines of High Runner mice that have been selectively bred for voluntary exercise on wheels have a cardiac phenotype that resembles the outcome of eccentric remodeling. Adult females (average age 55 days) from the 4 High Runner and 4 non-selected control lines were anaesthetized via vaporized isoflurane, then echocardiographic images were collected and analyzed for structural and functional differences. High Runner mice in general had lower ejection fractions compared to control mice lines (2-tailed p â€‹= â€‹0.023 6) and tended to have thicker walls of the anterior portion of the left ventricle (p â€‹= â€‹0.065). However, a subset of the High Runner individuals, termed mini-muscle mice, had greater ejection fraction (p â€‹= â€‹0.000 6), fractional shortening percentage (p â€‹< â€‹0.000 1), and ventricular mass at dissection (p â€‹< â€‹0.002 7 with body mass as a covariate) compared to non-mini muscle mice. Mice from replicate lines bred for high voluntary exercise did not all have inherent positive cardiac functional or structural characteristics, although a genetically unique subset of mini-muscle individuals did have greater functional cardiac characteristics, which in conjunction with their previously described peripheral aerobic enhancements (e.g., increased capillarity) would partially account for their increased V˙ O2max.

11.
J Sports Sci ; 41(11): 1093-1106, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37728081

RESUMEN

Race car drivers are often hypohydrated during a race. The FluidLogic drink system is a hands-free, prompted drinking system that is hypothesized to increase the likeliness of drivers' consuming fluids and thereby mitigating hypohydration. To test the hypothesis, 20 elite professional race car drivers participated in a 2-day cross-over study in which they drove on a race simulator in an environmental chamber that was heated to regulation cockpit temperature (38°C). Drivers used either the FluidLogic drink system or a standard in-car water bottle system (Control) on one of each testing day. The results indicated that there was consistent fluid consumption with the FluidLogic system, while the Control condition elicited fluid consumption in bolus doses. The Control condition was associated with moderate (0.5%) increased core body temperature (P < 0.05) and substantial (3.3%) increased urine-specific gravity (P < 0.001) as compared to the FluidLogic condition. Driving performance metrics indicated that lap times during the Control Condition were 5.1 ± 1.4 (4.1%) seconds slower (P < 0.05) than the FluidLogic Condition, due to driving errors that occurred in the high-speed corners. Based on these results, prompted hands-free drinking can mitigate hypohydration and performance loss in automobile racing drivers.


Asunto(s)
Conducción de Automóvil , Automóviles , Humanos , Estudios Cruzados , Calor
12.
BMC Plant Biol ; 23(1): 387, 2023 Aug 10.
Artículo en Inglés | MEDLINE | ID: mdl-37563571

RESUMEN

BACKGROUND: The family Lauraceae possesses ca. 50 genera and 2,500-3,000 species that are distributed in the pantropics. Only half of the genera of the family were represented in previously published plastome phylogenies because of the difficulty of obtaining research materials. Plastomes of Hypodaphnideae and the Mezilaurus group, two lineages with unusual phylogenetic positions, have not been previously reported and thus limit our full understanding on the plastome evolution of the family. Herbariomics, promoted by next generation sequencing technology, can make full use of herbarium specimens, and provides opportunities to fill the sampling gap. RESULTS: In this study, we sequenced five new plastomes (including four genera which are reported for the first time, viz. Chlorocardium, Hypodaphnis, Licaria and Sextonia) from herbarium specimens using genome skimming to conduct a comprehensive analysis of plastome evolution of Lauraceae as a means of sampling representatives of all major clades of the family. We identified and recognized six types of plastomes and revealed that at least two independent loss events at the IR-LSC boundary and an independent expansion of SSC occurred in the plastome evolution of the family. Hypodaphnis possesses the ancestral type of Lauraceae with trnI-CAU, rpl23 and rpl2 duplicated in the IR regions (Type-I). The Mezilaurus group shares the same plastome structure with the core Lauraceae group in the loss of trnI-CAU, rpl23 and rpl2 in the IRa region (Type-III). Two new types were identified in the Ocotea group: (1) the insertion of trnI-CAU between trnL-UAG and ccsA in the SSC region of Licaria capitata and Ocotea bracteosa (Type-IV), and (2) trnI-CAU and pseudogenizated rpl23 inserted in the same region of Nectandra angustifolia (Type-V). Our phylogeny suggests that Lauraceae are divided into nine major clades largely in accordance with the plastome types. The Hypodaphnideae are the earliest diverged lineage supported by both robust phylogeny and the ancestral plastome type. The monophyletic Mezilaurus group is sister to the core Lauraceae. CONCLUSIONS: By using herbariomics, we built a more complete picture of plastome evolution and phylogeny of the family, thus providing a convincing case for further use of herbariomics in phylogenetic studies of the Lauraceae.


Asunto(s)
Lauraceae , Lauraceae/genética , Filogenia , Secuencia de Bases , Evolución Molecular
13.
Ecol Evol ; 13(7): e10273, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37424937

RESUMEN

We made an in-depth review of historical studies of the cupressophyte conifer genus Cephalotaxus Siebold & Zucc. with an emphasis on its systematic position. We suggest that the systematic position of the genus is better understood using an integrative approach, so the evolution of phenetic characters is discussed within the context of recent phylogenomics. We propose that the genus should be classified as a separate family Cephalotaxaceae belonging to the clade consisting of Cupressaceae, Cephalotaxaceae, and Taxaceae; the family Cephalotaxaceae is sister to the Taxaceae but not nested within the Taxaceae and is characterized by a unique set of characters including morphology, anatomy, embryology, and chemistry. The family Cephalotaxaceae shows transitional characters between the Cupressaceae and the Taxaceae; the family possesses female cones with a primary cone axis bearing 5-8 pairs of decussate bracts, which is similar to the typical female cones of the Cupressaceae, on the one hand, and may have given rise to the reduced female cone of the Taxaceae with one terminal ovule partially or completely enclosed in a fleshy aril. In parallel, the compound male cone of the Cephalotaxaceae evolved into the seemingly "simple" male cones of the Taxaceae by means of reduction, elimination, and fusion.

14.
Med Sci Sports Exerc ; 55(12): 2160-2169, 2023 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-37486763

RESUMEN

INTRODUCTION: Growth restriction (GR) reduces ribosome abundance and skeletal muscle mass in mice. A reduction in skeletal muscle mass increases the risk of frailty and is associated with high morbidity and mortality rates. As eccentric type exercise increases muscle mass, this investigation aimed to determine if eccentric loading of skeletal muscle via downhill running (DHR) increased muscle mass in GR mice. METHODS: Mice were growth-restricted either gestational undernutrition (GUN, n = 8 litters), postnatal undernutrition (PUN, n = 8 litters), or were not restricted (CON, n = 8 litters) via a validated cross-fostering nutritive model. On postnatal day (PN) 21, all mice were weaned to a healthy diet, isolating the period of GR to early life as seen in humans. At PN45, mice were assigned to either a DHR (CON, n = 4 litters; GUN, n = 4 litters; PUN, n = 4 litters) or sedentary (SED: CON, n = 4 litters; GUN, n = 4 litters; PUN, n = 4 litters) group. Downhill running (16% decline: 18 m·min -1 ) was performed in 30-min bouts, three times per week, for 12 wk on a rodent treadmill. At PN129, the quadriceps femoris was dissected and evaluated for mass, myofiber size and type, and molecular markers of growth. RESULTS: Following training, CON-DHR mice having larger cells than CON-SED, GUN-SED, PUN-SED, and PUN-DHR mice ( P < 0.05). The PUN group (as compared with CON) had reduced body mass ( P < 0.001), upstream binding factor abundance ( P = 0.012), phosphor-mTOR ( P < 0.001), and quadriceps mass ( P = 0.02). The GUN and PUN groups had increased MuRF1 abundance ( P < 0.001) compared with CON ( P < 0.001). CONCLUSIONS: The blunted response to training suggests GR mice may have anabolic resistance when exposed to eccentric type exercise.


Asunto(s)
Desnutrición , Condicionamiento Físico Animal , Carrera , Humanos , Animales , Ratones , Músculo Cuádriceps , Carrera/fisiología , Músculo Esquelético/metabolismo , Desnutrición/complicaciones , Condicionamiento Físico Animal/fisiología
15.
Mol Neurobiol ; 60(10): 6133-6144, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37428404

RESUMEN

Proteasomal degradation of intrinsically disordered proteins, such as tau, is a critical component of proteostasis in both aging and neurodegenerative diseases. In this study, we investigated proteasomal activation by MK886 (MK). We previously identified MK as a lead compound capable of modulating tau oligomerization in a cellular FRET assay and rescuing P301L tau-induced cytotoxicity. We first confirmed robust proteasomal activation by MK using 20S proteasomal assays and a cellular proteasomal tau-GFP cleavage assay. We then show that MK treatment can significantly rescue tau-induced neurite pathology in differentiated SHSY5Y neurospheres. Due to this compelling result, we designed a series of seven MK analogs to determine if proteasomal activity is sensitive to structural permutations. Using the proteasome as the primary MOA, we examined tau aggregation, neurite outgrowth, inflammation, and autophagy assays to identify two essential substituents of MK that are required for compound activity: (1) removal of the N-chlorobenzyl group from MK negated both proteasomal and autophagic activity and reduced neurite outgrowth; and (2) removal of the indole-5-isopropyl group significantly improved neurite outgrowth and autophagy activity but reduced its anti-inflammatory capacity. Overall, our results suggest that the combination of proteasomal/autophagic stimulation and anti-inflammatory properties of MK and its derivatives can decrease tau-tau interactions and help rebalance dysfunctional proteostasis. Further development of MK to optimize its proteasomal, autophagic, and anti-inflammatory targets may lead to a novel therapeutic that would be beneficial in aging and neurodegenerative diseases.


Asunto(s)
Neuritas , Complejo de la Endopetidasa Proteasomal , Complejo de la Endopetidasa Proteasomal/metabolismo , Neuritas/metabolismo , Citoplasma/metabolismo , Indoles , Proteínas tau/metabolismo
16.
bioRxiv ; 2023 May 24.
Artículo en Inglés | MEDLINE | ID: mdl-37293082

RESUMEN

Malaria pathogenicity results from the parasite's ability to invade, multiply within and then egress from the host red blood cell (RBC). Infected RBCs are remodeled, expressing antigenic variant proteins (such as PfEMP1, coded by the var gene family) for immune evasion and survival. These processes require the concerted actions of many proteins, but the molecular regulation is poorly understood. We have characterized an essential Plasmodium specific Apicomplexan AP2 (ApiAP2) transcription factor in Plasmodium falciparum (PfAP2-MRP; Master Regulator of Pathogenesis) during the intraerythrocytic developmental cycle (IDC). An inducible gene knockout approach showed that PfAP2-MRP is essential for development during the trophozoite stage, and critical for var gene regulation, merozoite development and parasite egress. ChIP-seq experiments performed at 16 hour post invasion (h.p.i.) and 40 h.p.i. matching the two peaks of PfAP2-MRP expression, demonstrate binding of PfAP2-MRP to the promoters of genes controlling trophozoite development and host cell remodeling at 16 h.p.i. and antigenic variation and pathogenicity at 40 h.p.i. Using single-cell RNA-seq and fluorescence-activated cell sorting, we show de-repression of most var genes in Δpfap2-mrp parasites that express multiple PfEMP1 proteins on the surface of infected RBCs. In addition, the Δpfap2-mrp parasites overexpress several early gametocyte marker genes at both 16 and 40 h.p.i., indicating a regulatory role in the sexual stage conversion. Using the Chromosomes Conformation Capture experiment (Hi-C), we demonstrate that deletion of PfAP2-MRP results in significant reduction of both intra-chromosomal and inter-chromosomal interactions in heterochromatin clusters. We conclude that PfAP2-MRP is a vital upstream transcriptional regulator controlling essential processes in two distinct developmental stages during the IDC that include parasite growth, chromatin structure and var gene expression.

17.
J Cell Sci ; 136(11)2023 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-37288670

RESUMEN

Flagella are important for eukaryote cell motility, including in sperm, and are vital for life cycle progression of many unicellular eukaryotic pathogens. The '9+2' axoneme in most motile flagella comprises nine outer doublet and two central-pair singlet microtubules. T-shaped radial spokes protrude from the outer doublets towards the central pair and are necessary for effective beating. We asked whether there were radial spoke adaptations associated with parasite lineage-specific properties in apicomplexans and trypanosomatids. Following an orthologue search for experimentally uncharacterised radial spoke proteins (RSPs), we identified and analysed RSP9. Trypanosoma brucei and Leishmania mexicana have an extensive RSP complement, including two divergent RSP9 orthologues, necessary for flagellar beating and swimming. Detailed structural analysis showed that neither orthologue is needed for axoneme assembly in Leishmania. In contrast, Plasmodium has a reduced set of RSPs including a single RSP9 orthologue, deletion of which in Plasmodium berghei leads to failure of axoneme formation, failed male gamete release, greatly reduced fertilisation and inefficient life cycle progression in the mosquito. This indicates contrasting selection pressures on axoneme complexity, likely linked to the different mode of assembly of trypanosomatid versus Plasmodium flagella.


Asunto(s)
Parásitos , Plasmodium , Masculino , Animales , Axonema/metabolismo , Parásitos/metabolismo , Microtúbulos/metabolismo , Semillas , Proteínas/metabolismo , Flagelos/metabolismo , Eucariontes/metabolismo , Plasmodium/metabolismo , Dineínas/metabolismo
18.
ACS Bio Med Chem Au ; 3(3): 270-282, 2023 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-37363080

RESUMEN

Tumor necrosis factor (TNF) plays an important role in the pathogenesis of inflammatory and autoimmune diseases such as rheumatoid arthritis and Crohn's disease. The biological effects of TNF are mediated by binding to TNF receptors, TNF receptor 1 (TNFR1), or TNF receptor 2 (TNFR2), and this coupling makes TNFR1-specific inhibition by small-molecule therapies essential to avoid deleterious side effects. Recently, we engineered a time-resolved fluorescence resonance energy transfer biosensor for high-throughput screening of small molecules that modulate TNFR1 conformational states and identified zafirlukast as a compound that inhibits receptor activation, albeit at low potency. Here, we synthesized 16 analogues of zafirlukast and tested their potency and specificity for TNFR1 signaling. Using cell-based functional assays, we identified three analogues with significantly improved efficacy and potency, each of which induces a conformational change in the receptor (as measured by fluorescence resonance energy transfer (FRET) in cells). The best analogue decreased NF-κB activation by 2.2-fold, IκBα efficiency by 3.3-fold, and relative potency by two orders of magnitude. Importantly, we showed that the analogues do not block TNF binding to TNFR1 and that binding to the receptor's extracellular domain is strongly cooperative. Despite these improvements, the best candidate's maximum inhibition of NF-κB is only 63%, leaving room for further improvements to the zafirlukast scaffold to achieve full inhibition and prove its potential as a therapeutic lead. Interestingly, while we find that the analogues also bind to TNFR2 in vitro, they do not inhibit TNFR2 function in cells or cause any conformational changes upon binding. Thus, these lead compounds should also be used as reagents to study conformational-dependent activation of TNF receptors.

19.
Plants (Basel) ; 12(9)2023 Apr 24.
Artículo en Inglés | MEDLINE | ID: mdl-37176807

RESUMEN

Macrofossil evidence has demonstrated a first radiation of gnetophytes in the Early Cretaceous. However, the origin of the diversity of gnetophytes remains ambiguous because gnetalean macrofossils have rarely been reported from pre-Cretaceous strata. Here, we report a new putative gnetalean macrofossil reproductive shoot which possesses opposite phyllotaxy, long linear leaves more or less decurrent and having a prominent midvein and pedicled ovoid-ellipsoid and longitudinally striated chlamydosperms. Our new fossil is different from other known gnetalean macrofossils in the linear-lanceolate leaves with a midvein and pedicled chlamydosperms. As a result, we describe this new macrofossil reproductive shoot as new to science, i.e., Daohugoucladus sinensis gen. et sp. nov. Our new macrofossil displays additional morphological characters distinct from other known Mesozoic and modern gnetalean species and provides additional evidence of the origin and early evolution of female reproductive organs of gnetophytes.

20.
BMC Plant Biol ; 23(1): 155, 2023 Mar 22.
Artículo en Inglés | MEDLINE | ID: mdl-36945024

RESUMEN

BACKGROUND: Understanding the relationship between human evolution and environmental changes is the key to lifting the veil on human origin. The hypothesis that environmental changes triggered the divergence of humans from apes (ca. 9.3-6.5 million years ago, Ma) has been poorly tested because of limited continuous environmental data from fossil localities. Lufengpithecus (12.5-6.0 Ma) found on the southeastern margin of the Tibetan Plateau (SEMTP) across the ape-human split provides a good chance for testing this hypothesis. RESULTS: Here, we reconstructed the habitats of L. keiyuanensis (12.5-11.6 Ma) with comprehensive vegetation, climate, and potential food web data by palaeobotanical evidence, together with other multidisciplinary data and partly tested the environment-driven hypothesis by revealing the living conditions of Lufengpithecus. CONCLUSION: A detailed comparison of hominoids on different continents reveals their behaviour and fate divergence across the ape-human split against the background of global climate change, i.e., the stable living conditions of SEMTP not only provided a so-called 'refuge' for arboreal Lufengpithecus but also acted as a 'double-edged sword', preventing their further evolution while vegetation shifts in East Africa probably stimulated the emergence of human bipedalism, and the intense climatic changes in Europe possibly prevented those hominoids from surviving that time interval. Our findings provide interesting insight into the environmental impacts on the behavioural evolution of hominoids.


Asunto(s)
Hominidae , Condiciones Sociales , Animales , Humanos , Filogenia , Asia Oriental , Fósiles , Evolución Biológica
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