RESUMO
The COVID-19 pandemic is caused by the worldwide spread of the RNA virus SARS-CoV-2. Because of its mutational rate, wide geographical distribution, and host response variance this coronavirus is currently evolving into an array of strains with increasing genetic diversity. Most variants apparently have neutral effects for disease spread and symptom severity. However, in the viral spike protein, which is responsible for host cell attachment and invasion, the D614G variant, containing the amino acid substitution D to G in position 614, was suggested to increase viral infection capability. Here we propose a novel method to test the epidemiological impact of emergence of a new variant, by a combination of epidemiological curves (for new cases) and the temporal variation of relative frequencies of the variants through a logistic regression model. We applied our method to temporal distributions of SARS-CoV-2 D614 or G614, in two geographic areas: USA (East Coast versus West Coast) and Europe-Asia (East Countries versus West Countries). Our analysis shows that the D614G prevalence and the growth rates of COVID-19 epidemic data curves are correlated at the early stages and not correlated at the late stages, in both the USA and Europe-Asia scenarios. These results show that logistic models can reveal the potential selective advantage of D614G, which can explain, at least in part, the impact of this variant on COVID-19 epidemiology.
RESUMO
KEY MESSAGE: The early flowering system HSP::AtFT allowed a fast evaluation of a gene containment system based on the construct PsEND1::barnase-barstar for poplar. Transgenic lines showed disturbed pollen development and sterility. Vertical gene transfer through pollen flow from transgenic or non-native plant species into their crossable natural relatives is a major concern. Gene containment approaches have been proposed to reduce or even avoid gene flow among tree species. However, evaluation of genetic containment strategies for trees is very difficult due to the long-generation times. Early flowering induction would allow faster evaluation of genetic containment in this case. Although no reliable methods were available for the induction of fertile flowers in poplar, recently, a new early flowering approach was developed. In this study, early flowering poplar lines containing the gene construct PsEND1::barnase-barstar were obtained. The PsEND1 promoter was chosen due to its early expression pattern, its versality and efficiency for generation of male-sterile plants fused to the barnase gene. RT-PCRs confirmed barnase gene activity in flowers, and pollen development was disturbed, leading to sterile flowers. The system developed in this study represents a valuable tool for gene containment studies in forest tree species.
Assuntos
Proteínas de Bactérias/genética , Flores/crescimento & desenvolvimento , Edição de Genes/métodos , Infertilidade das Plantas/genética , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Pólen/crescimento & desenvolvimento , Populus/crescimento & desenvolvimento , Ribonucleases/genética , Proteínas de Arabidopsis/genética , Proteínas de Bactérias/metabolismo , Flores/genética , Flores/metabolismo , Flores/efeitos da radiação , Regulação da Expressão Gênica de Plantas , Fluxo Gênico , Vetores Genéticos , Resposta ao Choque Térmico , Plantas Geneticamente Modificadas/metabolismo , Plantas Geneticamente Modificadas/efeitos da radiação , Pólen/genética , Populus/genética , Populus/metabolismo , Populus/efeitos da radiação , Regiões Promotoras Genéticas , Ribonucleases/metabolismo , Temperatura , Transformação GenéticaRESUMO
RESUMEN El objetivo de este estudio fue caracterizar la condición corporal de caballos de rodeo chileno de élite en competencia. Se eligieron al azar 48 caballos raza chilena (15 hembras, 24 machos enteros y 9 machos castrados) participantes del 64° Campeonato Nacional de Rodeo Chileno. La condición corporal de cada caballo se evaluó por inspección visual y palpación según el sistema de Henneke. El rendimiento deportivo se registró como clasificados o no clasificados en la final del campeonato. Se construyeron tablas de frecuencia para la condición corporal por género y por rendimiento deportivo, se calcularon modas como descriptores de tendencia central y se comparó la condición corporal por género y rendimiento deportivo mediante la prueba de Kruskal-Wallis (p < 0,05). La condición corporal presentó una moda de 7, con un rango de 5 a 8. El 87,5% de los caballos tenía condición corporal entre 6 y 7 y se detectó un 6,3% de individuos obesos. No se encontraron diferencias significativas en relación al género ni rendimiento deportivo. Este es el primer estudio que reporta la condición corporal en caballos de rodeo chileno de élite y los resultados sugieren que los valores más frecuentes para esta variable en la raza están entre 6 a 7 puntos.
ABSTRACT The aim of this study was to characterize the distribution of body condition score for elite Chilean rodeo horses in competition. Forty-eight Chilean breed horses (15 mares, 24 stallions and 9 geldings) were randomly chosen for evaluation while participating at the 64th National Championship of Chilean Rodeo 2012. Body condition score for each horse was assessed by visual inspection and palpation according to the Henneke system. The sport performance was recorded as qualified or not qualified to the final round of the competition. Frequencies of body condition score were tabulated according to gender and according to sport performance of the horses. Modes were calculated as central tendency measurements and body condition score was compared between gender and sport performance groups by means of the Kruskal-Wallis test (p < 0.05). The mode of the general body condition score had a value of 7, with range between 5 and 8. 87.5% of the horses had body condition score between 6 and 7 points and 6.3% of them exhibited obesity. No significant differences were found both for gender and sport performance. This is the first study reporting body condition score in Chilean élite horses and results suggest that in the breed the most frequent value for this variable lies between 6 and 7 points.
RESUMO
How organisms adapt to unfavorable environmental conditions by means of plasticity or selection of favorable genetic variants is a central issue in evolutionary biology. In the Maipo River basin, the fish Basilichthys microlepidotus inhabits polluted and non-polluted areas. Previous studies have suggested that directional selection drives genomic divergence between these areas in 4% of Amplified Fragment Length Polymorphism (AFLP) loci, but the underlying genes and functions remain unknown. We hypothesized that B. microlepidotus in this basin has plastic and/or genetic responses to these conditions. Using RNA-Seq, we identified differentially expressed genes in individuals from two polluted sites compared with fish inhabiting non-polluted sites. In one polluted site, the main upregulated genes were related to cellular proliferation as well as suppression and progression of tumors, while biological processes and molecular functions involved in apoptotic processes were overrepresented in the upregulated genes of the second polluted site. The ornithine decarboxylase gene (related to tumor promotion and progression), which was overexpressed in both polluted sites, was sequenced, and a parallel pattern of a heterozygote deficiency and increase of the same homozygote genotype in both polluted sites compared with fish inhabiting the non-polluted sites was detected. These results suggest the occurrence of both a plastic response in gene expression and an interplay between phenotypic change and genotypic selection in the face of anthropogenic pollution.
Assuntos
Proteínas de Peixes/genética , Peixes/genética , Regulação da Expressão Gênica/efeitos dos fármacos , Marcadores Genéticos , Ornitina Descarboxilase/genética , Seleção Genética , Poluentes Químicos da Água/toxicidade , Animais , Evolução Biológica , Poluição Ambiental/efeitos adversos , Genótipo , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Polimorfismo GenéticoRESUMO
Bite mark evidence has been repeatedly found in criminal cases. Physical comparison of a bite mark to the teeth of available suspects may not always be possible. Experimental studies have shown that the analysis of DNA present in the saliva recovered from bite marks might help in the identification of individuals. However, the application of this approach to an actual criminal case has been reported only once before in forensic literature. Therefore, there is very limited scientific and technical information available on this subject. The current study focuses on a woman found dead in her home; the autopsy ruled the death to be a result of manual strangulation. A bite mark was found on each breast. The single swab technique was used to collect evidence from these bite marks, and an organic extraction method was employed for DNA isolation. Short tandem repeat (STR) sequence typing was performed using a commercially available kit, and the result was compared to the STR profile of a suspect. A full single-source STR profile was obtained from both bite marks, which matched the STR profile of the suspect. To the best of our knowledge, this is the second report on the analysis of DNA isolated from bite marks on the victim used to identify the crime perpetrator. Our results indicated that, contrary to most theoretical indications, a single swab technique for evidence collection and an organic method for DNA isolation could be very useful in solving this class of criminal cases.
Assuntos
Mordeduras e Picadas/diagnóstico , DNA/isolamento & purificação , Biologia Molecular/métodos , Saliva/metabolismo , Feminino , Humanos , Masculino , Repetições de Microssatélites/genética , Pessoa de Meia-IdadeRESUMO
This paper presents the design, experimental modeling, and control of a pump-driven renal perfusion pressure (RPP)-regulatory system to implement precise and relatively fast RPP regulation in rats. The mechatronic system is a simple, low-cost, and reliable device to automate the RPP regulation process based on flow-mediated occlusion. Hence, the regulated signal is the RPP measured in the left femoral artery of the rat, and the manipulated variable is the voltage applied to a dc motor that controls the occlusion of the aorta. The control system is implemented in a PC through the LabView software, and a data acquisition board NI USB-6210. A simple first-order linear system is proposed to approximate the dynamics in the experiment. The parameters of the model are chosen to minimize the error between the predicted and experimental output averaged from eight input/output datasets at different RPP operating conditions. A closed-loop servocontrol system based on a pole-placement PD controller plus dead-zone compensation was proposed for this purpose. First, the feedback structure was validated in simulation by considering parameter uncertainty, and constant and time-varying references. Several experimental tests were also conducted to validate in real time the closed-loop performance for stepwise and fast switching references, and the results show the effectiveness of the proposed automatic system to regulate the RPP in the rat, in a precise, accurate (mean error less than 2 mmHg) and relatively fast mode (10-15 s of response time).
Assuntos
Algoritmos , Biorretroalimentação Psicológica/instrumentação , Determinação da Pressão Arterial/instrumentação , Bombas de Infusão , Perfusão/instrumentação , Circulação Renal/fisiologia , Terapia Assistida por Computador/instrumentação , Animais , Pressão Sanguínea/fisiologia , Eletrônica Médica/instrumentação , Desenho de Equipamento , Análise de Falha de Equipamento , RatosRESUMO
The genetically heterogeneous taxon Candida parapsilosis was recently reclassified into three species: Candida parapsilosis, Candida orthopsilosis and Candida metapsilosis. The prevalences of these species among 141 bloodstream isolates tested in Brazil were 88% for C. parapsilosis, 9% for C. orthopsilosis, and 3% for C. metapsilosis. Except for three C. orthopsilosis isolates that were considered resistant to 5-flucytosine, all isolates representing the different species of this complex were susceptible to polyenes, triazoles and caspofungin.
Assuntos
Antifúngicos/farmacologia , Candida/efeitos dos fármacos , Candidíase/epidemiologia , Fungemia/epidemiologia , Antifúngicos/uso terapêutico , Brasil/epidemiologia , Candida/classificação , Candida/isolamento & purificação , Candidíase/microbiologia , Caspofungina , DNA Fúngico/análise , Farmacorresistência Fúngica , Equinocandinas/farmacologia , Equinocandinas/uso terapêutico , Flucitosina/farmacologia , Flucitosina/uso terapêutico , Fungemia/microbiologia , Humanos , Lipopeptídeos , Testes de Sensibilidade Microbiana , Técnicas de Tipagem Micológica , Polienos/farmacologia , Polienos/uso terapêutico , Vigilância da População , Prevalência , Triazóis/farmacologia , Triazóis/uso terapêuticoRESUMO
In an effort to unify the nomenclature of Trypanosoma cruzi, the causative agent of Chagas disease, an updated system was agreed upon at the Second Satellite Meeting. A consensus was reached that T. cruzi strains should be referred to by six discrete typing units (T. cruzi I-VI). The goal of a unified nomenclature is to improve communication within the scientific community involved in T. cruzi research. The justification and implications will be presented in a subsequent detailed report.
Assuntos
Terminologia como Assunto , Trypanosoma cruzi/classificação , AnimaisRESUMO
INTRODUCCION: La práctica de actividad física regular es una de las prioridades en salud pública para incrementar el bienestar y la calidad de vida especialmente en la tercera edad. Esta práctica depende de varios factores entre otros las experiencias previas de la conducta y la valoración de las ventajas y desventajas que tiene su realización. Propósito: Conocer los pros (ventajas) y Contras (desventajas) percibidos del ejercicio físico en adultos mayores. METODOLOGÍA: En este estudio se utilizó el balance decisional (Prochaska y Di Clemente1997). Se aplicó la aproximación cualitativa con muestreo teórico y análisis de contenido en una muestra de 15 participantes. Resultados: Estos mostraron tres categorías: Pros de la actividad física construida a partir de las subcategorías: mejorar la salud física y emocional e incrementar las relaciones interpersonales. La segunda categoría: Contras se construyó a partir de las subcategorías ambientales ocupaciones enfermedades y ser cuidadores de otras personas y una tercer categoría identificada se construyó con las razones para realizar la actividad física. CONCLUSIONES: Los pros y contras señalados por los participantes pueden ser la clave para el diseño de estrategias de programas de salud encaminados a incluir la actividad física en el adulto mayor.
Introduction: The practice of regular physical activity is one of the priorities in public Health to increase the well-being and the quality of life especially in the third age. This practice depends on several factors, among others the previous experiences of the conduct and evaluation of the advantages and disadvantages upon achievement. Purpose: Acknowledge pros and cons detected on physical exercise on older adults. Methodology: In this study the decisional balance (Prochaska and Di Clemente,1997) was used. The qualitive approach was applied by theoretical sampling and analysis of content sampling 15 participants. Results: They showed this categories: Pros of the physi cal activity, built from the subcategories: To improve the physical and emotional health and to increase the interpersonal relations. The second category, cons was formed from environmental Subcategories: Occupations, diseases and to carers of others persons and a third Identified category was the reasons of physical activity. Conclusions: The pros and cons distinguished by the participants can be the key for the strategic health programs design aimed to include physical activity on major adults.
Assuntos
Humanos , Masculino , Feminino , Idoso , Idoso de 80 Anos ou mais , Atividade Motora , IdosoRESUMO
Chagas disease is still a major public health problem in Latin America. Its causative agent, Trypanosoma cruzi, can be typed into three major groups, T. cruzi I, T. cruzi II and hybrids. These groups each have specific genetic characteristics and epidemiological distributions. Several highly virulent strains are found in the hybrid group; their origin is still a matter of debate. The null hypothesis is that the hybrids are of polyphyletic origin, evolving independently from various hybridization events. The alternative hypothesis is that all extant hybrid strains originated from a single hybridization event. We sequenced both alleles of genes encoding EF-1alpha, actin and SSU rDNA of 26 T. cruzi strains and DHFR-TS and TR of 12 strains. This information was used for network genealogy analysis and Bayesian phylogenies. We found T. cruzi I and T. cruzi II to be monophyletic and that all hybrids had different combinations of T. cruzi I and T. cruzi II haplotypes plus hybrid-specific haplotypes. Bootstrap values (networks) and posterior probabilities (Bayesian phylogenies) of clades supporting the monophyly of hybrids were far below the 95% confidence interval, indicating that the hybrid group is polyphyletic. We hypothesize that T. cruzi I and T. cruzi II are two different species and that the hybrids are extant representatives of independent events of genome hybridization, which sporadically have sufficient fitness to impact on the epidemiology of Chagas disease.
Assuntos
Teorema de Bayes , Quimera/genética , Haplótipos/genética , Filogenia , Trypanosoma cruzi/classificação , Trypanosoma cruzi/genética , Actinas/genética , Animais , Intervalos de Confiança , DNA Ribossômico/genética , Evolução Molecular , Fator 1 de Elongação de Peptídeos/genética , Reação em Cadeia da PolimeraseRESUMO
Gene expression "noise" is commonly defined as the stochastic variation of gene expression levels in different cells of the same population under identical growth conditions. Here, we tested whether this "noise" is amplified with time, as a consequence of decoherence in global gene expression profiles (genome-wide microarrays) of synchronized cells. The stochastic component of transcription causes fluctuations that tend to be amplified as time progresses, leading to a decay of correlations of expression profiles, in perfect analogy with elementary relaxation processes. Measuring decoherence, defined here as a decay in the auto-correlation function of yeast genome-wide expression profiles, we found a slowdown in the decay of correlations, opposite to what would be expected if, as in mixing systems, correlations decay exponentially as the equilibrium state is reached. Our results indicate that the populational variation in gene expression (noise) is a consequence of temporal decoherence, in which the slow decay of correlations is a signature of strong interdependence of the transcription dynamics of different genes.
Assuntos
Perfilação da Expressão Gênica , Genoma Fúngico , Saccharomyces cerevisiae/genética , Regulação Fúngica da Expressão Gênica , Saccharomyces cerevisiae/crescimento & desenvolvimentoRESUMO
Beef proteins are considered non-setting proteins and usually gels obtained by adding of microbial transglutaminase are obtained by cooking directly the solubilized paste. The aim of this work was to determine the effect of pre-heating treatments on the mechanical properties of restructured beef gels treated with microbial transglutaminase (MTG). The effect of cooling (cold binding) the solubilized pastes after the pre-heating treatments was also studied. The restructured beef gels were obtained by adding 0.3% MTG or 0% MTG (control). Three pre-heating temperatures (40, 50 or 60°C) for 30 or 60min were studied, followed by heating at 90°C for 15min. Control samples without pre-heating were also prepared. Cold binding was studied by holding pre-heated gels at 4°C for 12h before heating at 90°C for 15min. Changes in mechanical properties (texture profile analysis and puncture test), color attributes, expressible water and cooking loss were determined. Results indicated that the better mechanical properties can be obtained by pre-heating beef pastes at 50°C for 30min with minimal effect on color, expressible water and cooking loss when 0.3% of MTG is added. It was concluded that there were no practical advantages by pre-heating the gels for 60min. Cold binding did not improve the mechanical properties of beef gels.
RESUMO
Deletions on chromosomes 5 and 7 are frequently seen in myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). It is assumed that these deletions indicate loss of tumor suppressor genes on these chromosomes and until these tumor suppressor genes are identified, the functional consequences of these deletions and the molecular basis of these myeloid disorders cannot be completely understood. We evaluated loss of heterozygosity (LOH) in 44 patients (18 MDS and 26 AML, diagnosed according to WHO classification criteria) at diagnosis, using a four-microsatellite marker panel: an intragenic marker on the 7th intron of gene IRF-1 of the 5q31.1 region and three markers located inside the 7q31.1 region and correlated the LOH with karyotype abnormalities. The microsatellites chosen corresponded to chromosome regions frequently deleted in MDS/AML. The samples with Q (peak area) less than or equal to 0.50 were indicative of LOH. The percent of informative samples (i.e., heterozygous) for the intragenic microsatellite in gene IRF-1 and in loci D7S486, D7S515 and D7S522 were 66.6, 73.7, 75.5, and 48.8%, respectively. Cytogenetic abnormalities by G-banding were found in 36% (16/44) of the patients (2 of 18 MDS and 14 of 26 AML patients). We found a significantly positive association of the occurrence of LOH with abnormal karyotype (P < 0.05; chi-square test) and there were cases with LOH but the karyotype was normal (by G-banding). These data indicate that LOH in different microsatellite markers is possibly an event previous to chromosomal abnormalities in these myeloid neoplasias.
Assuntos
Aberrações Cromossômicas , Fator Regulador 1 de Interferon/genética , Leucemia Mieloide Aguda/genética , Perda de Heterozigosidade/genética , Síndromes Mielodisplásicas/genética , Marcadores Genéticos , Humanos , Repetições de Microssatélites/genética , Reação em Cadeia da PolimeraseRESUMO
Deletions on chromosomes 5 and 7 are frequently seen in myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). It is assumed that these deletions indicate loss of tumor suppressor genes on these chromosomes and until these tumor suppressor genes are identified, the functional consequences of these deletions and the molecular basis of these myeloid disorders cannot be completely understood. We evaluated loss of heterozygosity (LOH) in 44 patients (18 MDS and 26 AML, diagnosed according to WHO classification criteria) at diagnosis, using a four-microsatellite marker panel: an intragenic marker on the 7th intron of gene IRF-1 of the 5q31.1 region and three markers located inside the 7q31.1 region and correlated the LOH with karyotype abnormalities. The microsatellites chosen corresponded to chromosome regions frequently deleted in MDS/AML. The samples with Q (peak area) less than or equal to 0.50 were indicative of LOH. The percent of informative samples (i.e., heterozygous) for the intragenic microsatellite in gene IRF-1 and in loci D7S486, D7S515 and D7S522 were 66.6, 73.7, 75.5, and 48.8 percent, respectively. Cytogenetic abnormalities by G-banding were found in 36 percent (16/44) of the patients (2 of 18 MDS and 14 of 26 AML patients). We found a significantly positive association of the occurrence of LOH with abnormal karyotype (P < 0.05; chi-square test) and there were cases with LOH but the karyotype was normal (by G-banding). These data indicate that LOH in different microsatellite markers is possibly an event previous to chromosomal abnormalities in these myeloid neoplasias.
Assuntos
Humanos , Aberrações Cromossômicas , Fator Regulador 1 de Interferon/genética , Leucemia Mieloide Aguda/genética , Perda de Heterozigosidade/genética , Síndromes Mielodisplásicas/genética , Marcadores Genéticos , Repetições de Microssatélites/genética , Reação em Cadeia da PolimeraseAssuntos
Peso Corporal , Cavalos/fisiologia , Animais , Animais Recém-Nascidos/fisiologia , Feminino , Masculino , Linhagem , Valores de ReferênciaRESUMO
The analysis of transcriptional temporal noise could be an interesting means to study gene expression dynamics and stochasticity in eukaryotes. To study the statistical distributions of temporal noise in the eukaryotic model system Saccharomyces cerevisiae, we analyzed microarray data corresponding to one cell cycle for 6200 genes. We found that the temporal noise follows a lognormal distribution with scale invariance at the genome, chromosomal and sub-chromosomal levels. Correlation of temporal noise with the codon adaptation index suggests that at least 70% of all protein-coding genes are a noise minimization core of the genome. Accordingly, a mathematical model of individual gene expression dynamics was proposed, using an operator theoretical approach, which reveals strict conditions for noise variability and a possible global noise minimization/optimization strategy at the genome level. Our model and data show that minimal noise does not correspond to genes obeying a strictly deterministic dynamics. The natural strategy of minimization consists in equating the mean of the absolute value of the relative variation of the expression level (alpha) with noise (eta). We hypothesize that the temporal noise pattern is an emergent property of the genome and shows how the dynamics of gene expression could be related to chromosomal organization.
Assuntos
Genoma Fúngico , Saccharomyces cerevisiae/genética , Transcrição Gênica , Regulação Fúngica da Expressão Gênica , Redes Reguladoras de Genes , Modelos Genéticos , Modelos Estatísticos , Modelos Teóricos , Análise de Sequência com Séries de Oligonucleotídeos , Saccharomyces cerevisiae/metabolismo , Fatores de TempoRESUMO
The objective of this study was to identify midgut microvillar proteins in insects appearing earlier (Coleoptera) and later (Lepidoptera) in evolution. For this, cytoskeleton-free midgut microvillar membrane from Spodoptera frugiperda (Lepidoptera) and Tenebrio molitor (Coleoptera) were used to raise antibodies. These were used for screening midgut cDNA expression libraries. Positive clones were sequenced, assembled and searched for similarities with gene/protein databases. The predicted midgut microvillar proteins from T. molitor were: cockroach allergens (unknown function), peritrophins (peritrophic membrane proteins), digestive enzymes (aminopeptidase, alpha-mannosidase) and unknown proteins. Predicted S. frugiperda midgut proteins may be grouped into six classes: (a) proteins involved in protection of midgut (thioredoxin peroxidase, aldehyde dehydrogenase, serpin and juvenile hormone epoxide hydrolase); (b) digestive enzymes (astacin, transporter-like amylase, aminopeptidase, and carboxypeptidase); (c) peritrophins; (d) proteins associated with microapocrine secretion (gelsolin, annexin); (e) membrane-tightly bound-cytoskeleton proteins (fimbrin, calmodulin) and (f) unidentified proteins. The novel approach is compared with others and microvillar function is discussed in the light of the predicted proteins.
Assuntos
Trato Gastrointestinal/metabolismo , Biblioteca Gênica , Proteínas de Insetos/metabolismo , Microvilosidades/metabolismo , Spodoptera/metabolismo , Tenebrio/metabolismo , Animais , Anticorpos/imunologia , Evolução Biológica , Trato Gastrointestinal/imunologia , Perfilação da Expressão Gênica , Proteínas de Insetos/genética , Proteínas de Insetos/imunologia , Microvilosidades/imunologia , Spodoptera/genética , Spodoptera/imunologia , Tenebrio/genética , Tenebrio/imunologiaRESUMO
The analysis of transcriptional temporal noise could be an interesting means to study gene expression dynamics and stochasticity in eukaryotes. To study the statistical distributions of temporal noise in the eukaryotic model system Saccharomyces cerevisiae, we analyzed microarray data corresponding to one cell cycle for 6200 genes. We found that the temporal noise follows a lognormal distribution with scale invariance at the genome, chromosomal and sub-chromosomal levels. Correlation of temporal noise with the codon adaptation index suggests that at least 70% of all protein-coding genes are a noise minimization core of the genome. Accordingly, a mathematical model of individual gene expression dynamics was proposed, using an operator theoretical approach, which reveals strict conditions for noise variability and a possible global noise minimization/optimization strategy at the genome level. Our model and data show that minimal noise does not correspond to genes obeying a strictly deterministic dynamics. The natural strategy of minimization consists in equating the mean of the absolute value of the relative variation of the expression level (alpha) with noise (eta). We hypothesize that the temporal noise pattern is an emergent property of the genome and shows how the dynamics of gene expression could be related to chromosomal organization.
Assuntos
Genoma Fúngico , Saccharomyces cerevisiae/genética , Transcrição Gênica , Análise de Sequência com Séries de Oligonucleotídeos , Fatores de Tempo , Modelos Estatísticos , Modelos Genéticos , Modelos Teóricos , Redes Reguladoras de Genes , Regulação Fúngica da Expressão Gênica , Saccharomyces cerevisiae/metabolismoRESUMO
Proper morphology is essential for the ability of Candida albicans to switch between yeast and hyphae and thereby sustain its virulence. Here we identified, by differential screening, a novel C. albicans AAA ATPase encoding gene, CaYLL34 (RIX7), with enhanced expression in hyphae. Phylogenetic analysis suggests that CaYLL34 belongs to a "VCP-like" subgroup of AAA ATPases essential for yeast viability and contains a bipartite nuclear localization signal. Inactivation of one copy of CaYLL34, by the URA-Blaster method, generated the heterozygous mutant strain M61. This strain has severe phenotypic alterations, such as a highly increased vacuole, abnormal cell shape and reduced growth in different conditions. Also, major pathogenicity factors are affected in M61, for instance, a significant decrease of hypha formation (>90%), surface biofilm adhesion (86%) and secreted aspartyl proteinase activity (76.5%). Our results show that the partial impairment of CaYll34p cellular levels is sufficient to affect the proper cellular morphology and pathogenicity factors and suggest that this protein is required for biogenesis of ribosomal subunits. Accordingly, we propose that the product of CaYLL34 could be tested as a novel target for antifungal drugs.
Assuntos
Adenosina Trifosfatases/genética , Ácido Aspártico Endopeptidases/metabolismo , Biofilmes/crescimento & desenvolvimento , Candida albicans/genética , Proteínas de Saccharomyces cerevisiae/genética , Sequência de Bases , Candida albicans/enzimologia , Candida albicans/crescimento & desenvolvimento , Hifas/enzimologia , Hifas/genética , Hifas/crescimento & desenvolvimento , Dados de Sequência Molecular , Mutação , Proteínas Nucleares , Filogenia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de DNARESUMO
Proper morphology is essential for the ability of Candida albicans to switch between yeast and hyphae and thereby sustain its virulence. Here we identified, by differential screening, a novel C. albicans AAA ATPase encoding gene, CaYLL34 (RIX7), with enhanced expression in hyphae. Phylogenetic analysis suggests that CaYLL34 belongs to a [quot ]VCP-like[quot ] subgroup of AAA ATPases essential for yeast viability and contains a bipartite nuclear localization signal. Inactivation of one copy of CaYLL34, by the URA-Blaster method, generated the heterozygous mutant strain M61. This strain has severe phenotypic alterations, such as a highly increased vacuole, abnormal cell shape and reduced growth in different conditions. Also, major pathogenicity factors are affected in M61, for instance, a significant decrease of hypha formation (>90%), surface biofilm adhesion (86%) and secreted aspartyl proteinase activity (76.5%). Our results show that the partial impairment of CaYll34p cellular levels is sufficient to affect the proper cellular morphology and pathogenicity factors and suggest that this protein is required for biogenesis of ribosomal subunits. Accordingly, we propose that the product of CaYLL34 could be tested as a novel target for antifungal drugs.