Long-Term Monitoring of Aphid-Transmitted Viruses in Melon and Zucchini Crops: Genetic Diversity and Population Structure of Cucurbit Aphid-Borne Yellows Virus and Watermelon Mosaic Virus.

Understanding the emergence and prevalence of viral diseases in crops requires the systematic epidemiological monitoring of viruses, as well as the analysis of how ecological and evolutionary processes combine to shape viral population dynamics. Here, we extensively monitored the occurrence of six aphid-transmitted viruses in melon and zucchini crops in Spain for 10 consecutive cropping seasons between 2011 and 2020. The most prevalent viruses were cucurbit aphid-borne yellows virus (CABYV) and watermelon mosaic virus (WMV), found in 31 and 26% of samples with yellowing and mosaic symptoms. Other viruses, such as zucchini yellow mosaic virus, cucumber mosaic virus, Moroccan watermelon mosaic virus, and papaya ring spot virus, were detected less frequently (<3%) and mostly in mixed infections. Notably, our statistical analysis showed a significant association between CABYV and WMV in melon and zucchini hosts, suggesting that mixed infections might be influencing the evolutionary epidemiology of these viral diseases. We then carried out a comprehensive genetic characterization of the full-length genome sequences from CABYV and WMV isolates by using the Pacific Biosciences single-molecule real-time (PacBio) high-throughput technology to assess the genetic variation and structure of their populations. Our results showed that the CABYV population displayed seven codons under positive selection, and although most isolates clustered in the Mediterranean clade, a subsequent analysis of molecular variance revealed a significant, fine-scale temporal structure, which was in part explained by the level of the variance between isolates from single and mixed infections. In contrast, the WMV population genetic analysis showed that most of the isolates grouped into the Emergent clade, with no genetic differentiation and under purifying selection. These results underlie the epidemiological relevance of mixed infections for CABYV and provide a link between genetic diversity and CABYV dynamics at the whole-genome level.

An in vitro model of neuronal ensembles.

Advances in 3D neuronal cultures, such as brain spheroids and organoids, are allowing unprecedented in vitro access to some of the molecular, cellular and developmental mechanisms underlying brain diseases. However, their efficacy in recapitulating brain network properties that encode brain function remains limited, thereby precluding development of effective in vitro models of complex brain disorders like schizophrenia. Here, we develop and characterize a Modular Neuronal Network (MoNNet) approach that recapitulates specific features of neuronal ensemble dynamics, segregated local-global network activities and a hierarchical modular organization. We utilized MoNNets for quantitative in vitro modelling of schizophrenia-related network dysfunctions caused by highly penetrant mutations in SETD1A and 22q11.2 risk loci. Furthermore, we demonstrate its utility for drug discovery by performing pharmacological rescue of alterations in neuronal ensembles stability and global network synchrony. MoNNets allow in vitro modelling of brain diseases for investigating the underlying neuronal network mechanisms and systematic drug discovery.

Implications of mixed viral infections on plant disease ecology and evolution.

Mixed viral infections occur more commonly than would be expected by chance in nature. Virus-virus interactions may affect viral traits and leave a genetic signature in the population, and thus influence the prevalence and emergence of viral diseases. Understanding about how the interactions between viruses within a host shape the evolutionary dynamics of the viral populations is needed for viral disease prevention and management. Here, we first synthesize concepts implied in the occurrence of virus-virus interactions. Second, we consider the role of the within-host interactions of virus-virus and virus-other pathogenic microbes, on the composition and structure of viral populations. Third, we contemplate whether mixed viral infections can create opportunities for the generation and maintenance of viral genetic diversity. Fourth, we attempt to summarize the evolutionary response of viral populations to mixed infections to understand how they shape the spatio-temporal dynamics of viral populations at the individual plant and field scales. Finally, we anticipate the future research under the reconciliation of molecular epidemiology and evolutionary ecology, drawing attention to the need of adding more complexity to future research in order to gain a better understanding about the mechanisms operating in nature.

Long-Term Cocirculation of Two Strains of Pepino Mosaic Virus in Tomato Crops and Its Effect on Population Genetic Variability.

Mixed viral infections are common in plants, and the evolutionary dynamics of viral populations may differ depending on whether the infection is caused by single or multiple viral strains. However, comparative studies of single and mixed infections using viral populations in comparable agricultural and geographical locations are lacking. Here, we monitored the occurrence of pepino mosaic virus (PepMV) in tomato crops in two major tomato-producing areas in Murcia (southeastern Spain), supporting evidence showing that PepMV disease-affected plants had single infections of the Chilean 2 (CH2) strain in one area and the other area exhibited long-term (13 years) coexistence of the CH2 and European (EU) strains. We hypothesized that circulating strains of PepMV might be modulating the differentiation between them and shaping the evolutionary dynamics of PepMV populations. Our phylogenetic analysis of 106 CH2 isolates randomly selected from both areas showed a remarkable divergence between the CH2 isolates, with increased nucleotide variability in the geographical area where both strains cocirculate. Furthermore, the potential virus-virus interaction was studied further by constructing six full-length infectious CH2 clones from both areas, and assessing their viral fitness in the presence and absence of an EU-type isolate. All CH2 clones showed decreased fitness in mixed infections and although complete genome sequencing indicated a nucleotide divergence of those CH2 clones by area, the magnitude of the fitness response was irrespective of the CH2 origin. Overall, these results suggest that although agroecological cropping practices may be particularly important for explaining the evolutionary dynamics of PepMV in tomato crops, the cocirculation of both strains may have implications on the genetic variability of PepMV populations.

A miniaturized multi-clamp CMOS amplifier for intracellular neural recording.

Intracellular electrophysiology is a foundational method in neuroscience and uses electrolyte-filled glass electrodes and benchtop amplifiers to measure and control transmembrane voltages and currents. Commercial amplifiers perform such recordings with high signal-to-noise ratios (SNRs) but are often expensive, bulky, and not easily scalable to many channels due to reliance on board-level integration of discrete components. Here, we present a monolithic complementary-metal-oxide-semiconductor (CMOS) multi-clamp amplifier integrated circuit capable of recording both voltages and currents with performance exceeding that of commercial benchtop instrumentation. Miniaturization enables high-bandwidth current mirroring, facilitating the synthesis of large-valued active resistors with lower noise than their passive equivalents. This enables the realization of compensation modules that can account for a wide range of electrode impedances. We validate the amplifier's operation electrically, in primary neuronal cultures, and in acute slices, using both high-impedance sharp and patch electrodes. This work provides a solution for low-cost, high-performance and scalable multi-clamp amplifiers.

Perspectivas éticas, legales y deontológicas de los documentos del consentimiento informado enfermero / The ethical, legal and deontological pespectives of nurse informed consent documents

El consentimiento informado se fundamenta en el respeto a la autonomía de los pacientes. Es un procedimiento de diálogo entre el paciente y el profesional sanitario que permite a las personas enfermas expresar su decisión sobre su cuerpo, su vida y su salud, y a los profesionales respetar la libertad de aquellos, permitiéndoles asumir sus responsabilidades en la toma de decisiones sobre sí mismos. En su ámbito laboral, aun teniendo clara la obligación de informar verbalmente, las enfermeras/os llevan a cabo procedimientos y técnicas para las que se requiere (o se debería requerir) previamente la obtención del consentimiento informado por escrito de la persona (o la familia) que va a ser objeto de dicha intervención. Las publicaciones muestran un papel controvertido, y a veces erróneo, del papel de los profesionales enfermeros respecto del consentimiento informado. La exigencia, en ocasiones, de que sean las enfermeras/os las que entreguen y obtengan el consentimiento informado para intervenciones que realizan los médicos es un ejemplo de dicho conflicto. La evolución de la teoría del consentimiento informado, donde los pacientes tienen cada vez un papel más decisivo y autónomo, afecta de lleno a los profesionales enfermeros. Se requiere potenciar la comunicación con el paciente, proporcionar un trato más humano y aumentar la calidad asistencial (AU)

Informed consent is based on respect for patients' autonomy. It is a procedure of dialogue between the patient and the healthcare professional, which allows sick persons to express their decision about their body, their life and health, and professionals to respect the freedom of the former, allowing them to take the responsibility for decisions made about themselves. In their work setting, even when there is a clear duty for providing oral information, nurses conduct procedures and techniques which require (or should require) a previous informed consent in written by the person who will undergo said intervention (or their family). Publications show a controversial and sometimes wrong role of nursing professionals regarding informed consent. Demanding on some occasions that nurses must provide and obtain the informed consent for interventions conducted by physicians is an example of said conflict. The evolution of the informed consent theory, where patients are playing an increasingly decisive and autonomous role, has a full impact on nursing professionals. It is necessary to boost communication with patients, to provide a more humane treatment, and to increase the quality of care (AU)

Diverse roles of guanine nucleotide exchange factors in regulating collective cell migration.

Efficient collective migration depends on a balance between contractility and cytoskeletal rearrangements, adhesion, and mechanical cell-cell communication, all controlled by GTPases of the RHO family. By comprehensive screening of guanine nucleotide exchange factors (GEFs) in human bronchial epithelial cell monolayers, we identified GEFs that are required for collective migration at large, such as SOS1 and ß-PIX, and RHOA GEFs that are implicated in intercellular communication. Down-regulation of the latter GEFs differentially enhanced front-to-back propagation of guidance cues through the monolayer and was mirrored by down-regulation of RHOA expression and myosin II activity. Phenotype-based clustering of knockdown behaviors identified RHOA-ARHGEF18 and ARHGEF3-ARHGEF28-ARHGEF11 clusters, indicating that the latter may signal through other RHO-family GTPases. Indeed, knockdown of RHOC produced an intermediate between the two phenotypes. We conclude that for effective collective migration, the RHOA-GEFs → RHOA/C → actomyosin pathways must be optimally tuned to compromise between generation of motility forces and restriction of intercellular communication.

Delamination of neural crest cells requires transient and reversible Wnt inhibition mediated by Dact1/2.

Delamination of neural crest (NC) cells is a bona fide physiological model of epithelial-to-mesenchymal transition (EMT), a process that is influenced by Wnt/ß-catenin signalling. Using two in vivo models, we show that Wnt/ß-catenin signalling is transiently inhibited at the time of NC delamination. In attempting to define the mechanism underlying this inhibition, we found that the scaffold proteins Dact1 and Dact2, which are expressed in pre-migratory NC cells, are required for NC delamination in Xenopus and chick embryos, whereas they do not affect the motile properties of migratory NC cells. Dact1/2 inhibit Wnt/ß-catenin signalling upstream of the transcriptional activity of T cell factor (TCF), which is required for EMT to proceed. Dact1/2 regulate the subcellular distribution of ß-catenin, preventing ß-catenin from acting as a transcriptional co-activator to TCF, yet without affecting its stability. Together, these data identify a novel yet important regulatory element that inhibits ß-catenin signalling, which then affects NC delamination.

Seeds of Locally Aligned Motion and Stress Coordinate a Collective Cell Migration.

We find how collective migration emerges from mechanical information transfer between cells. Local alignment of cell velocity and mechanical stress orientation-a phenomenon dubbed "plithotaxis"-plays a crucial role in inducing coordinated migration. Leader cells at the monolayer edge better align velocity and stress to migrate faster toward the open space. Local seeds of enhanced motion then generate stress on neighboring cells to guide their migration. Stress-induced motion propagates into the monolayer as well as along the monolayer boundary to generate increasingly larger clusters of coordinately migrating cells that move faster with enhanced alignment of velocity and stress. Together, our analysis provides a model of long-range mechanical communication between cells, in which plithotaxis translates local mechanical fluctuations into globally collective migration of entire tissues.

ß-Pix directs collective migration of anterior visceral endoderm cells in the early mouse embryo.

Collective epithelial migration is important throughout embryonic development. The underlying mechanisms are poorly understood but likely involve spatially localized activation of Rho GTPases. We previously reported that Rac1 is essential for generating the protrusive activity that drives the collective migration of anterior visceral endoderm (AVE) cells in the early mouse embryo. To identify potential regulators of Rac1, we first performed an RNAi screen of Rho family exchange factors (guanine nucleotide exchange factor [GEF]) in an in vitro collective epithelial migration assay and identified ß-Pix. Genetic deletion of ß-Pix in mice disrupts collective AVE migration, while high-resolution live imaging revealed that this is associated with randomly directed protrusive activity. We conclude that ß-Pix controls the spatial localization of Rac1 activity to drive collective AVE migration at a critical stage in mouse development.

Sonic hedgehog signaling switches the mode of division in the developing nervous system.

The different modes of stem cell division are tightly regulated to balance growth and differentiation during organ development and homeostasis, and these regulatory processes are subverted in tumor formation. Here, we developed markers that provided the single-cell resolution necessary to quantify the three modes of division taking place in the developing nervous system in vivo: self-expanding, PP; self-replacing, PN; and self-consuming, NN. Using these markers and a mathematical model that predicts the dynamics of motor neuron progenitor division, we identify a role for the morphogen Sonic hedgehog in the maintenance of stem cell identity in the developing spinal cord. Moreover, our study provides insight into the process linking lineage commitment to neurogenesis with changes in cell-cycle parameters. As a result, we propose a challenging model in which the external Sonic hedgehog signal dictates stem cell identity, reflected in the consequent readjustment of cell-cycle parameters.

Identification of a putative transcriptome signature common to neuroblastoma and neural crest cells.

Neuroblastoma, the most common extracranial tumor in children, is caused by genetic lesions in neural crest precursors of the peripheral nervous system. However, since neural crest cells are neither present after birth and nor are they readily accessible for analysis, very little is known about the genetic networks they might share with neuroblastoma cells during their development, despite their common embryonic origin. Here we have developed a novel resource for lineage tracing and for the isolation of neural crest cells in the chick embryo, enabling us to perform a genome-wide expression screen in neural crest progenitors. In this analysis, we efficiently retrieved known neural crest specific genes that validate our screening strategy and we identified new genes that participate in diverse cell activities, yet with a strong representation of genes associated to cell signaling and cell mobility, two hallmarks of migratory cells. We crossed this transcriptome data with that in the neuroblastoma gene server to search for the human orthologues of these genes associated with neuroblastoma. Accordingly, we retrieved 54 genes expressed strongly in both populations, from which we were able to validate a total of 27 genes expressed in the neural crest that are relevant to neuroblastoma formation. We propose that neural crest and neuroblastoma tumor cells share a common genetic signature that might serve to characterize neuroblastoma cancer stem cells, thereby contributing to the identification of specific targets against which new therapeutic strategies can be designed.

LMO4 is an essential cofactor in the Snail2-mediated epithelial-to-mesenchymal transition of neuroblastoma and neural crest cells.

Neuroblastoma is an embryonic tumor derived from cells of the neural crest. Taking advantage of a newly developed neural crest lineage tracer and based on the hypothesis that the molecular mechanisms that mediate neural crest delamination are also likely to be involved in the spread of neuroblastoma, we were able to identify genes that are active both in neural crest development and neuroblastoma tumor formation. A subsequent search of the neuroblastoma gene server for human orthologues of genes differentially expressed in the chick embryo neural crest screen retrieved the LIM domain only protein 4 (LMO4), which was expressed in both cell types analyzed. Functional experiments in these two model systems revealed that LMO4 activity is required for neuroblastoma cell invasion and neural crest delamination. Moreover, we identified LMO4 as an essential cofactor in Snail2-mediated cadherin repression and in the epithelial-to-mesenchymal transition of both neural crest and neuroblastoma cells. Together, our results suggest that the association of high levels of LMO4 with aggressive neuroblastomas is dependent on LMO4 regulation of cadherin expression and hence, tumor invasiveness.

Jagged2 controls the generation of motor neuron and oligodendrocyte progenitors in the ventral spinal cord.

In the developing spinal cord, motor neurons (MNs) and oligodendrocytes arise sequentially from a common pool of progenitors. However, the genetic network responsible for this neurogenesis to gliogenesis switch is largely unknown. A transcriptome analysis identified the Notch ligand Jagged2 (JAG2) as a Sonic hedgehog-regulated factor transiently expressed in MN progenitors (pMNs). In vivo loss- and gain-of-function experiments show that JAG2 schedules the differentiation of the pMN progenitors. At early developmental stages, Olig2 expressing pMN progenitors that enter the differentiation pathway exclusively generate MNs. At these times, the activation of the Notch pathway by JAG2 maintains selected pMN progenitors in an undifferentiated state by two mechanisms; first it inhibits MN generation by reducing Olig2 proteins levels, and second it directly inhibits the premature generation of oligodendrocyte progenitors (OLPs) by maintaining high levels of Hes5. Later, extinction of JAG2 from the pMN results in the loss of Hes5 expression, heralding the gliogenic phase of pMN progenitors. Strikingly, downregulation of JAG2 in pMN progenitors is sufficient to promote the precocious generation of OLPs. Together these data provide evidence that JAG2 is a key regulator of the timely and ordered generation of two of the defining cell types in the spinal cord, MNs and OLPs.

Canonical BMP7 activity is required for the generation of discrete neuronal populations in the dorsal spinal cord.

BMP activity is essential for many steps of neural development, including the initial role in neural induction and the control of progenitor identities along the dorsal-ventral axis of the neural tube. Taking advantage of chick in ovo electroporation, we show a novel role for BMP7 at the time of neurogenesis initiation in the spinal cord. Using in vivo loss-of-function experiments, we show that BMP7 activity is required for the generation of three discrete subpopulations of dorsal interneurons: dI1-dI3-dI5. Analysis of the BMP7 mouse mutant shows the conservation of this activity in mammals. Furthermore, this BMP7 activity appears to be mediated by the canonical Smad pathway, as we demonstrate that Smad1 and Smad5 activities are similarly required for the generation of dI1-dI3-dI5. Moreover, we show that this role is independent of the patterned expression of progenitor proteins in the dorsal spinal cord, but depends on the BMP/Smad regulation of specific proneural proteins, thus narrowing this BMP7 activity to the time of neurogenesis. Together, these data establish a novel role for BMP7 in primary neurogenesis, the process by which a neural progenitor exits the cell cycle and enters the terminal differentiation pathway.

Expression of TGF-betas in the embryonic nervous system: analysis of interbalance between isoforms.

Transforming growth factor-beta (TGF-beta) is a family of growth factors with essential and multiple roles during embryonic development. In mammals, three isoforms (TGF-beta1, TGF-beta2, TGF-beta3) have been described. In the nervous system, the presence of TGF-beta1 has remained undetectable in other structures than meninges and choroids plexus, while TGF-beta2 and TGF-beta3 were considered as the neural members of the family. In the present study, we have analysed the expression pattern of the three isoforms in the neural tube, brain, and spinal cord during development in both mouse and chicken. The data reveal specific patterns for each isoform. This work also shows that both TGF-beta1 and TGF-beta3 are expressed in neural crest cells. In addition, we demonstrate the existence of interbalance between TGF-beta1 and TGF-beta3 with possible functional implications, which, together with the expression of TGF-beta1 in the CNS, represents one of the most important contributions of this work.

Opiniones de los profesionales sanitarios sobre la influencia del Programa de Actividades Preventivas y de Promoción de la Salud (PAPPS) en atención primaria / Opinions of health professionals on the impact of the preventive activities and health promotion program (PAPPS)

Objetivo: conocer la opinión de los profesionales de Atención Primaria (APS) sobre el impacto y el papel del Programa de Actividades Preventivas y de Promoción de la Salud (PAPPS). Diseño: estudio descriptivo cuali-cuantitativo. En una primera fase se empleó la técnica DAFO. En una segunda fase se diseñó un cuestionario de 47 ítems con respuestas mediante una escala ordinal. Ámbito: nivel de Atención Primaria de Salud. Participantes: profesionales de centros de salud PAPPS, responsables del PAPPS y gestores de APS, usando como criterios de segmentación la Comunidad Autónoma, y el tiempo de adscripción o conocimiento del PAPPS. En el estudio cualitativo se hizo una selección por muestreo teorético de 62 participantes; en el estudio cuantitativo, 198 profesionales respondieron a la encuesta. Mediciones principales: la valoración de los resultados se hizo teniendo en cuenta las respuestas a las preguntas formuladas y realizando un análisis cruzado entre fortalezas/amenazas y debilidades/oportunidades. Análisis estadístico descriptivo de las preguntas del cuestionario. Resultados: existe acuerdo en que el PAPPS ha tenido una gran influencia en el desarrollo de la APS, contribuyendo a mejorar la calidad asistencial, pero también en que es fundamental tratar de dinamizar el programa, siendo la principal debilidad la escasa implicación de los profesionales con las recomendaciones preventivas postuladas por falta de motivación y por el desgaste profesional. Conclusiones: Según los participantes el PAPPS ha contribuido de manera significativa al desarrollo de la APS en nuestro país y ha influido sobre la práctica profesional inculcando una cultura de prevención que antes apenas existía (AU)

Objective: to find out the opinion of Primary Health Care (PHC) professionals on the impact of the Preventive Activities and Health Promotion Program (PAPPS). Design: descriptive qualitative-quantitative study. In a first phase the SWOT technique was used. In a second phase a 47 items questionnaire was designed using an ordinal scale. Participants: professionals of PAPPS health centre, PAPPS managers and PHC management, using the Autonomous Community, and the time of ascribing or knowledge of PAPPS as segmentation criteria. In the qualitative study 62 participants were selected by theoretical sampling. In the quantitative study, 198 professionals took part in the survey. Principal measurements: the assessment of the results has taken into account the responses to the questions formulated and by performing a crossed analysis between strengths/threats and weaknesses/opportunities. A descriptive statistical analysis of the questions in the questionnaire. Results: there is agreement in that PAPPS has greatly influenced the development of PHC, contributing to improving the quality of care, but it is also fundamental to try revitalise the programme, as the limited involvement by the professionals in the postulated preventive recommendations is its main weakness, due to lack of motivation and professional burn-out. Conclusions: according to the participants PAPPS has contributed significantly to the development of PHC in our country and has had an influence on professional practice by instilling a prevention culture that hardly existed before (AU)

[Opinions of health professionals on the impact of the Preventive Activities and Health Promotion Program (PAPPS)]. / Opiniones de los profesionales sanitarios sobre la influencia del Programa de Actividades Preventivas y de Promoción de la Salud (PAPPS) en atención primaria.

OBJECTIVE: To find out the opinion of Primary Health Care (PHC) professionals on the impact of the Preventive Activities and Health Promotion Program (PAPPS). DESIGN: Descriptive qualitative-quantitative study. In a first phase the SWOT technique was used. In a second phase a 47 item questionnaire was designed using an ordinal scale. PARTICIPANTS: Professionals of PAPPS health centre, PAPPS managers and PHC management, using the Autonomous Community, and the time of ascribing or knowledge of PAPPS as segmentation criteria. In the qualitative study 62 participants were selected by theoretical sampling. In the quantitative study, 198 professionals took part in the survey. PRINCIPAL MEASUREMENTS: The assessment of the results has taken into account the responses to the questions formulated and by performing a crossed analysis between strengths/threats and weaknesses/opportunities. A descriptive statistical analysis of the questions in the questionnaire. RESULTS: There is agreement in that PAPPS has greatly influenced the development of PHC, contributing to improving the quality of care, but it is also fundamental to try revitalise the programme, as the limited involvement by the professionals in the postulated preventive recommendations is its main weakness, due to lack of motivation and professional burn-out.. CONCLUSIONS: According to the participants PAPPS has contributed significantly to the development of PHC in our country and has had an influence on professional practice by instilling a prevention culture that hardly existed before.

Frequency of the VO2max plateau phenomenon in world-class cyclists.

We aimed to determine the frequency of the VO2max plateau phenomenon in top-level male professional road cyclists (n = 38; VO2max [mean +/- SD]: 73.5 +/- 5.5 ml.kg(-1).min(-1)) and in healthy, sedentary male controls (n = 37; VO2max: 42.7 +/- 5.6 ml.kg(-1).min(-1)). All subjects performed a continuous incremental cycle-ergometer test of 1-min workloads until exhaustion. Power output was increased from a starting value of 25 W (cyclists) or 20 W (controls) at the rate of 25 W.min(-1) (cyclists) or 20 W.min(-1) (controls) until volitional exhaustion. We measured gas-exchange and heart rate (HR) throughout the test. Blood concentrations of lactate (BLa) were measured at end-exercise in both groups. We defined maximal exercise exertion as the attainment of a respiratory exchange rate (RER) >or= 1.1; HR > 95 % age-predicted maximum; and BLa > 8 mmo.l(-1). The VO2max plateau phenomenon was defined as an increase in two or more consecutive 1-min mean VO2 values of less than 1.5 ml.kg(-1).min(-1). Most cyclists met our criteria for maximal exercise effort (RER > 1.1, 100 %; 95 % predicted maximal HR [HRmax], 82 %; BLa > 8 mmol.l(-1), 84 %). However, the proportion of cyclists attaining a V.O (2max) plateau was considerably lower, i.e., 47 %. The majority of controls met the criteria for maximal exercise effort (RER > 1.1, 100 %; predicted HRmax, 68 %; BLa > 8 mmol. l(-1), 73 %), but the proportion of these subjects with a VO2max plateau was only 24 % (significantly lower proportion than in cyclists [p < 0.05]). Scientists should consider 1) if typical criteria of attainment of maximal effort are sufficiently stringent, especially in elite endurance athletes; and 2) whether those humans exhibiting the VO2max plateau phenomenon are those who perform an absolute maximum effort or there are additional distinctive features associated with this phenomenon.