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The intracellular [ATP]/[ADP] ratio is crucial for Escherichia coli's cellular functions, impacting transport, phosphorylation, signaling, and stress responses. Overexpression of F1-ATPase genes in E. coli increases glucose consumption, lowers energy levels, and triggers transcriptional responses in central carbon metabolism genes, particularly glycolytic ones, enhancing carbon flux. In this contribution, we report the impact of the perturbation of the energetic level in a PTS- mutant of E. coli by modifying the [ATP]/[ADP] ratio by uncoupling the cytoplasmic activity of the F1 subunit of the ATP synthase. The disruption of [ATP]/[ADP] ratio in the evolved strain of E. coli PB12 (PTS-) was achieved by the expression of the atpAGD operon encoding the soluble portion of ATP synthase F1-ATPase (strain PB12AGD+). The analysis of the physiological and metabolic response of the PTS- strain to the ATP disruption was determined using RT-qPCR of 96 genes involved in glucose and acetate transport, glycolysis and gluconeogenesis, pentose phosphate pathway (PPP), TCA cycle and glyoxylate shunt, several anaplerotic, respiratory chain, and fermentative pathways genes, sigma factors, and global regulators. The apt mutant exhibited reduced growth despite increased glucose transport due to decreased energy levels. It heightened stress response capabilities under glucose-induced energetic starvation, suggesting that the carbon flux from glycolysis is distributed toward the pentose phosphate and the Entner-Duodoroff pathway with the concomitant. Increase acetate transport, production, and utilization in response to the reduction in the [ATP]/[ADP] ratio. Upregulation of several genes encoding the TCA cycle and the glyoxylate shunt as several respiratory genes indicates increased respiratory capabilities, coupled possibly with increased availability of electron donor compounds from the TCA cycle, as this mutant increased respiratory capability by 240% more than in the PB12. The reduction in the intracellular concentration of cAMP in the atp mutant resulted in a reduced number of upregulated genes compared to PB12, suggesting that the mutant remains a robust genetic background despite the severe disruption in its energetic level.
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Escherichia coli is the best-known model for the biotechnological production of many biotechnological products, including housekeeping and heterologous primary and secondary metabolites and recombinant proteins, and is an efficient biofactory model to produce biofuels to nanomaterials. Glucose is the primary substrate used as the carbon source for laboratory and industrial cultivation of E. coli for production purposes. Efficient growth and associated production and yield of desired products depend on the efficient sugar transport capabilities, sugar catabolism through the central carbon catabolism, and the efficient carbon flux through specific biosynthetic pathways. The genome of E. coli MG1655 is 4,641,642 bp, corresponding to 4702 genes encoding 4328 proteins. The EcoCyc database describes 532 transport reactions, 480 transporters, and 97 proteins involved in sugar transport. Nevertheless, due to the high number of sugar transporters, E. coli uses preferentially few systems to grow in glucose as the sole carbon source. E. coli nonspecifically transports glucose from the extracellular medium into the periplasmic space through the outer membrane porins. Once in periplasmic space, glucose is transported into the cytoplasm by several systems, including the phosphoenolpyruvate-dependent phosphotransferase system (PTS), the ATP-dependent cassette (ABC) transporters, and the major facilitator (MFS) superfamily proton symporters. In this contribution, we review the structures and mechanisms of the E. coli central glucose transport systems, including the regulatory circuits recruiting the specific use of these transport systems under specific growing conditions. Finally, we describe several successful examples of transport engineering, including introducing heterologous and non-sugar transport systems for producing several valuable metabolites.
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INTRODUCCIÓN. A nivel mundial la tuberculosis es una de las diez causas de muerte, con una incidencia de 7 920 pacientes entre 0 14 años en la región de América; siendo el abdomen el sitio extrapulmonar más común. OBJETIVOS. Describir las características etarias, clínicas, microbio-lógicas, complicaciones y comorbilidades asociadas en los pacientes pediátricos con tuberculosis abdominal. MATERIALES Y MÉTODOS. Estudio retrospectivo, base de datos de 23 pacientes y edades de 0 meses a 17 años 11 meses y 29 días de edad con evidencia confirmatoria de la presencia del microorganismo; de los servicios de Gastroenterología y Epidemiología en el Nuevo Hospital Civil de Guadalajara "Dr. Juan I. Menchaca ", período 2007 a 2018. RESULTADOS. Se informaron 47,8% (11; 23) de sexo masculino y 52,2% (12; 23) de sexo femenino; 26,1% (6; 23) con antecedente de ingesta de lácteos no pasteurizados. Los tres datos clínicos más frecuentes fueron dolor abdominal, fiebre y pérdida de peso. El 8,7% (2;23) tuvieron convivencia con personas con tuberculosis activa positivo; 30,4% (7; 23) registraron prueba cutánea de derivado proteico pu-rificado positiva; 30,4% (7; 23) identificación de bacterias ácido-alcohol resistentes positivo; 43,5% (10; 23) estudios de imagen compatibles; 8,7% (2; 23) proteína C reactiva de mucosa intestinal po-sitivo; 4,3% (1; 36) cultivo positivo y 8,7% (2; 23) pacientes con inmunodeficiencia. CONCLUSIÓN. La tuberculosis abdominal, se presentó en menores de edad con síntomas inespecíficos de dolor abdominal, fiebre y pérdida de peso, expuestos a ingesta de productos lácteos no pasteurizados, combe positivo e inmunodeficiencia.
INTRODUCTION. Worldwide, tuberculosis is one of the ten causes of death, with an incidence of 7 920 patients between 0 - 14 years in the Americas region; the abdomen being the most common extrapulmonary site. OBJECTIVES. Describe the age, clinical, microbiological, complications and associated comorbidities in pediatric patients with abdominal tuberculosis. MATERIALS AND ME-THODS. Retrospective study, database of 23 patients and ages from 0 months of age to 17 years 11 months and 29 days of age with confirmatory evidence of the presence of the microorganism; of the Gastroenterology and Epidemiology services at the New Civil Hospital of Guadalajara "Dr. Juan I. Menchaca ", period 2 007 to 2 018. RESULTS. 47,8% (11; 23) men and 52,2% (12; 23) women were reported; 26,1% (6; 23) with a history of unpasteurized dairy intake. The three most frequent clinical data were abdominal pain, fever and weight loss. 8,7% (2; 23) lived together with people with positive active tuberculosis; 30,4% (7; 23) recorded a positive purified protein derivative skin test; 30,4% (7; 23) positive acid-alcohol resistant bacteria identification; 43,5% (10; 23) compatible imaging studies; 8,7% (2; 23) positive intestinal mucosal C-reactive protein; 4,3% (1; 36) positive culture and 8,7% (2; 23) patients with immunodeficiency. CONCLUSION. Abdominal tuberculosis occurred in minors with nonspecific symptoms of abdominal pain, fever and weight loss, exposed to intake of unpasteurized dairy products, positive combe and immunodeficiency
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Humanos , Masculino , Feminino , Recém-Nascido , Lactente , Pré-Escolar , Criança , Adolescente , Tuberculose Bovina , Tuberculose Gastrointestinal , Tuberculose dos Linfonodos , Diagnóstico por Imagem , Laticínios , Mycobacterium tuberculosis , Tomografia , Contaminação de Alimentos , Reação em Cadeia da Polimerase , Epidemiologia , Diagnóstico , Perfuração Intestinal , Laparotomia , Mycobacterium bovisRESUMO
Moringa oleifera Lam. (Moringa), Jatropha curcas L. (Jatropha), and Ricinus communis L. (Ricinus) are oily species known by their capability to grow in tropical and subtropical lands. However, there are no studies comparing their growth and recovery capabilities after root pruning and transplant. The purpose of this research was to compare and analyze propagation, growth, and recovery performance of these species after root pruning and transplant. We sowed 100 seeds per species and monitored their survival and growth during a 63-day period; after this, we uprooted the plants and pruned their roots 4.0 cm from their base and transplanted them. We monitored their recovery over 83 days, and then uprooted plants and measured above- and belowground data, digitized their roots in three dimensions, and calculated biomass fractions. With this information, we established allometric equations to estimate biomass fractions and root distribution models. Results indicated that Ricinus had the highest propagation capabilities. Jatropha and Ricinus had similar recovery after root pruning and transplant. Moringa had the lowest propagation and recovery from transplant. Concerning belowground data, root pruning increased root density more than three times in Moringa, four times in Ricinus, and six times in Jatropha. Nevertheless, the three species maintained natural root trays. Ricinus had the longest and thinnest roots and the highest number of branches, followed by Jatropha, and finally Moringa, with the smallest quantity and the shortest and thickest roots. We concluded that the three species recovered well from root pruning and transplant, with improved root structure upon applying these practices.
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ABSTRACT This research evaluated the changes on populations of culturable N-fixing free bacteria (NFFB) and P-solubilizing bacteria (PSB), as well as on the root nodulation by native rhizobia, the root colonization and spore number of arbuscular mycorrhizal fungi (AMF), in the rhizosphere of Clitoria ternatea and Brachiaria brizantha grown in mesocosms contaminated with crude oil (0, 3000, 6000, 9000, and 12000 mg kg-1), for 240 days. After 24 h of soil contamination, the highest populations of NFFB and PSB (5.5 and 4.9 LogUFC, respectively) were found in control, and the lowest populations were obtained at 12000 mg kg-1 (5.1 and 4.2 LogUFC, respectively). In contrast, at 60 and 240 days, the control showed lower populations of NFFB and PSB (5.4 and 4.8 LogUFC, respectively) than contaminated treatments. The highest number of root nodules in C. ternatea was quantified in control at 60 and 240 days (25 and 27 nodules, respectively) in comparison to those observed at the treatment with 12000 mg kg-1 (7 and 1 nodule, respectively). At 60 days, AMF colonization in both plant species, and the number of spores significantly decreased as the crude oil concentration increased; however, at 240 days, the highest number of AMF spores was recorded at treatments with 6000 and 12000 mg kg-1. The dry weight of both plant species significantly decreased as crude oil concentrations increased. Although C. ternatea was more susceptible to the toxic effects of crude oil, this plant species showed greater content of total chlorophyll than B. brizantha.
RESUMEN Esta investigación evaluó los cambios en la población cultivable de bacterias de vida libre fijadoras de nitrógeno (BVLFN) y de bacterias solubilizadoras de fósforo (BSP), así como en la nodulación de raíces por rizobios nativos, y en la colonización y número de esporas de hongos micorrízicos arbusculares (HMA) en la rizósfera de Clitoria ternatea y Brachiaria brizantha cultivadas en mesocosmos contaminados con petróleo crudo (0, 3000, 6000, 9000 y 12000 mg kg-1), durante 240 días. A las 24 h de la contaminación del suelo, las poblaciones más altas de BVLFN y BSP (5,5 y 4,9 LogUFC, respectivamente) se encontraron en el control, mientras que las poblaciones más bajas se obtuvieron a 12000 mg kg-1 (5,1 y 4,2 LogUFC, respectivamente). En contraste, a los 60 y 240 días, el control mostró bajas poblaciones de BVLFN y BSP (5,4 y 4,8 LogUFC, respectivamente) que los tratamientos contaminados. El mayor número de nódulos en raíz de C. ternatea se cuantificó en el control a los 60 y 240 días (25 y 27 nódulos, respectivamente) en comparación con el tratamiento con 12000 mg kg-1 (7 y 1 nódulos, respectivamente). A los 60 días, la colonización de HMA en ambas especies vegetales y el número de esporas disminuyeron significativamente al aumentar la concentración de petróleo crudo; sin embargo, a los 240 días, se registró el mayor número de esporas de HMA en los tratamientos con 6000 y 12000 mg kg-1. El peso seco vegetal disminuyó significativamente al aumentar las concentraciones de petróleo crudo. Clitoria ternatea fue más susceptible a la toxicidad del petróleo, aunque esta especie vegetal mostró mayor contenido de clorofila total que B. brizantha.
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The occurrence of pests and diseases can affect plant health and productivity in ecosystems that are already at risk, such as tropical montane cloud forests. The use of naturally occurring microorganisms is a promising alternative to mitigate forest tree fungal pathogens. The objectives of this study were to isolate rhizobacteria associated with five Lauraceae species from a Mexican tropical montane cloud forest and to evaluate their antifungal activity against Fusarium solani and F. oxysporum. Fifty-six rhizobacterial isolates were assessed for mycelial growth inhibition of Fusarium spp. through dual culture assays. Thirty-three isolates significantly reduced the growth of F. solani, while 21 isolates inhibited that of F. oxysporum. The nine bacterial isolates that inhibited fungal growth by more than 20% were identified through 16S rDNA gene sequence analysis; they belonged to the genera Streptomyces, Arthrobacter, Pseudomonas, and Staphylococcus. The volatile organic compounds (VOC) produced by these nine isolates were evaluated for antifungal activity. Six isolates (Streptomyces sp., Arthrobacter sp., Pseudomonas sp., and Staphylococcus spp.) successfully inhibited F. solani mycelial growth by up to 37% through VOC emission, while only the isolate INECOL-21 (Pseudomonas sp.) inhibited F. oxysporum. This work provides information on the microbiota of Mexican Lauraceae and is one of the few studies identifying forest tree-associated microbes with inhibitory activity against tree pathogens.
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Antifúngicos/farmacologia , Bactérias/metabolismo , Fusarium/efeitos dos fármacos , Lauraceae/microbiologia , Compostos Orgânicos Voláteis/farmacologia , Antifúngicos/química , Antifúngicos/metabolismo , Bactérias/química , Bactérias/classificação , Bactérias/isolamento & purificação , Fusarium/crescimento & desenvolvimento , Fusarium/fisiologia , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Microbiologia do Solo , Compostos Orgânicos Voláteis/química , Compostos Orgânicos Voláteis/metabolismoRESUMO
Zymomonas mobilis ZM4 is an ethanol-producing microbe that is constitutively tolerant to this solvent. For a better understanding of the ethanol tolerance phenomenon we obtained and characterized two ZM4 mutants (ER79ap and ER79ag) with higher ethanol tolerance than the wild-type. Mutants were evaluated in different ethanol concentrations and this analysis showed that mutant ER79ap was more tolerant and had a better performance in terms of cell viability, than the wild-type strain and ER79ag mutant. Genotyping of the mutant strains showed that both carry non-synonymous mutations in clpP and spoT/relA genes. A third non-synonymous mutation was found only in strain ER79ap, in the clpB gene. Considering that ER79ap has the best tolerance to added ethanol, the mutant alleles of this strain were evaluated in ZM4 and here we show that while all of them contribute to ethanol tolerance, mutation within spoT/relA gene seems to be the most important.
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Ambrosia beetles, along with termites and leafcutter ants, are the only fungus-farming lineages within the tree of life. Bacteria harbored by ambrosia beetles may play an essential role in the nutritional symbiotic interactions with their associated fungi; however, little is known about the impact of rearing conditions on the microbiota of ambrosia beetles. We have used culture-independent methods to explore the effect of rearing conditions on the microbiome associated with Xyleborus affinis, Xyleborus bispinatus, and Xyleborus volvulus, evaluating different media in laboratory-controlled conditions and comparing wild and laboratory conditions. Our results revealed that rearing conditions affected the fungal and bacterial microbiome structure and had a strong influence on bacterial metabolic capacities. We propose that the rearing conditions influence the ambrosia-associated fungal and bacterial communities. Furthermore, bacterial microbiome flexibility may help beetles adapt to different substrates.
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This paper proposes a facile strategy for the zwitterionization of bioceramics that is based on the direct incorporation of l-lysine amino acid via the ε-amino group onto mesoporous MCM-41 materials. Fourier transform infrared (FTIR) studies of lysine-grafted MCM-41 (MCM-LYS) simultaneously showed bands at 3080 and 1540 cm-1 and bands at 1625 and 1415 cm-1 corresponding to -NH3+/COO- pairs, which demonstrate the incorporation of the amino acid on the material surface keeping its zwitterionic character. Both elemental and thermogravimetric analyses showed that the amount of grafted lysine was 8 wt. % based on the bioceramic total weight. Moreover, MCM-LYS exhibited a reduction of adhesion of S. aureus and E. coli bacteria in 33% and 50%, respectively at physiological pH, as compared with pristine MCM-41. Biofilm studies onto surfaces showed that lysine functionalization elicited a reduction of the area covered by S. aureus biofilm from 42% to only 5% (88%). This research shows a simple and effective approach to chemically modify bioceramics using single amino acids that provides zwitterionic functionality, which is useful to develop new biomaterials that are able to resist bacterial adhesion.
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Unlike most biofuel species, Jatropha curcas has promise for use in marginal lands, but it may serve an additional role by stabilizing soils. We evaluated the growth and structural responsiveness of young J. curcas plants to diverse soil conditions. Soils included a sand, a sandy-loam, and a clay-loam from eastern Mexico. Growth and structural parameters were analyzed for shoots and roots, although the focus was the plasticity of the primary root system architecture (the taproot and four lateral roots). The sandy soil reduced the growth of both shoot and root systems significantly more than sandy-loam or clay-loam soils; there was particularly high plasticity in root and shoot thickness, as well as shoot length. However, the architecture of the primary root system did not vary with soil type; the departure of the primary root system from an index of perfect symmetry was 14 ± 5% (mean ± standard deviation). Although J. curcas developed more extensively in the sandy-loam and clay-loam soils than in sandy soil, it maintained a consistent root to shoot ratio and root system architecture across all types of soil. This strong genetic determination would make the species useful for soil stabilization purposes, even while being cultivated primarily for seed oil.