Broad antibacterial spectrum, high oral bioavailability and excellent tissue penetration combined with safety and few, yet rare, unwanted effects, have made the quinolones class of antimicrobials one ...of the most used in inpatients and outpatients. Initially discovered during the search for improved chloroquine-derivative molecules with increased anti-malarial activity, today the quinolones, intended as antimicrobials, comprehend four generations that progressively have been extending antimicrobial spectrum and clinical use. The quinolone class of antimicrobials exerts its antimicrobial actions through inhibiting DNA gyrase and Topoisomerase IV that in turn inhibits synthesis of DNA and RNA. Good distribution through different tissues and organs to treat Gram-positive and Gram-negative bacteria have made quinolones a good choice to treat disease in both humans and animals. The extensive use of quinolones, in both human health and in the veterinary field, has induced a rise of resistance and menace with leaving the quinolones family ineffective to treat infections. This review revises the evolution of quinolones structures, biological activity, and the clinical importance of this evolving family. Next, updated information regarding the mechanism of antimicrobial activity is revised. The veterinary use of quinolones in animal productions is also considered for its environmental role in spreading resistance. Finally, considerations for the use of quinolones in human and veterinary medicine are discussed.
Few sclerophyllous plants from the central coast of Chile have been systematically studied. This work describes the phytochemical composition and antimicrobial properties of
Pers. (sin.
), a shrub ...found in the first line and near the Pacific coast.
has been traditionally used by indigenous inhabitants of today's central Chile for its medicinal properties. Few reports exist regarding the phytochemistry characterization and biological activities of
. A hydroalcoholic extract of
was prepared from leaves and small branches. Qualitative phytochemical characterization indicated the presence of alkaloids, steroids, terpenoids, flavonoids, phenolic, and tannin compounds. The antimicrobial activity of this extract was assessed in a panel of microorganisms including Gram-positive bacteria, Gram-negative bacteria, and pathogenic yeasts. The extract displayed an important antimicrobial effect against Gram-positive bacteria,
and
but not against Gram-negatives, for which an intact Lipopolysaccharide is apparently the determinant of resistance to
extracts. The hydroalcoholic extract was then fractionated through a Sephadex LH-20/methanol-ethyl acetate column. Afterward, the fractions were pooled according to a similar pattern visualized by TLC/UV analysis. Fractions obtained by this criterion were assessed for their antimicrobial activity against
. The fraction presenting the most antimicrobial activity was HPLC-ESI-MS/MS, obtaining molecules related to caffeoylquinic acid, dicaffeoylquinic acid, and quercetin, among others. In conclusion, the extracts of
showed strong antimicrobial activity, probably due to the presence of metabolites derived from phenolic acids, such as caffeoylquinic acid, and flavonoids, such as quercetin, which in turn could be responsible for helping with wound healing. In addition, the development of antimicrobial therapies based on the molecules found in
could help to combat infection caused by pathogenic yeasts and Gram-positive bacteria, without affecting the Gram-negative microbiota.
Ciprofloxacin is the choice treatment for infections caused by
Typhi, however, reduced susceptibility to ciprofloxacin has been reported for this pathogen. Considering the decreased approbation of ...new antimicrobials and the crisis of resistance, one strategy to combat this problem is to find new targets that enhances the antimicrobial activity for approved antimicrobials. In search of mutants with increased susceptibility to ciprofloxacin; 3,216 EZ-Tn
transposon mutants of
. Typhi were screened.
Typhi
::EZ-Tn
mutants susceptible to ciprofloxacin were confirmed by agar diffusion and MIC assays. The genes carrying EZ-Tn
transposon insertions were sequenced. Null mutants of interrupted genes, as well as inducible genetic constructs, were produced using site-directed mutagenesis, to corroborate phenotypes. SDS-PAGE and Real-time PCR were used to evaluate the expression of proteins and genes, respectively. Five mutants with increased ciprofloxacin susceptibility were found in the screening. The first confirmed mutant was the glutamine synthetase-coding gene
. Analysis of outer membrane proteins revealed increased OmpF, a channel for the influx of ciprofloxacin and nalidixic acid, in the
mutant. Expression of
increased four times in the
null mutant compared to WT strain. To understand the relationship between the expression of
and
, a strain with the
gene under control of the tetracycline-inducible P
promoter was created, to modulate
expression. Induction of
decreased expression of
, at the same time that reduced susceptibility to ciprofloxacin. Expression of sRNA MicF, a negative regulator of OmpF was reduced to one-fourth in the
mutant, compared to WT strain. In addition, expression of
and
genes (encoding the two-component system NtrC/B that may positively regulate OmpF) were increased in the
mutant. Further studies indicate that deletion of
decreases susceptibility to CIP, while deletion of
gene increases susceptibility CIP. Our findings indicate that
inactivation promotes
expression, that translates into increased OmpF protein, facilitating the entry of ciprofloxacin, thus increasing susceptibility to ciprofloxacin through 2 possible mechanisms.
Currently, Salmonella enterica serovar Typhimurium (S. Typhimurium), is a major global public health problem, which has caused food-borne illnesses in many countries. Today, with the extensive use of ...antimicrobials, antimicrobial resistance is increasing at a serious rate in S. Typhimurium isolates. The present study sought the role of cysteine (Cys) auxotrophy on the resistance to quinolones and paraquat in S. Typhimurium. Cys auxotrophy was achieved by deleting either the cysDNC, cysJIH or cysQ loci. Deletion of these loci resulted in loss of susceptibility against nalidixic acid, levofloxacin, ciprofloxacin (CIP) and paraquat. Further studies with cysJIH mutant indicated increased expression of multi-antibiotic resistance genes marA and ramA, and consequently increased expression of efflux-pump systems. The cysJIH mutant presented a smaller increase of reactive oxygen species (ROS) in presence of paraquat or CIP. Expression of katG and sodA (expressing for a catalase and a superoxide dismutase, respectively) genes was increased in presence of paraquat in the cysJIH mutant; while expression of the superoxide dismutase gene sodB was decreased. These results indicate that deletion of cysDNC, cysJIH or cysQ genes of S. Typhimurium renders Cys auxotrophy along with decreased susceptibility in response to quinolone and paraquat. Overexpression of efflux-pump systems AcrB-TolC and SmvA-OmpD and antioxidant enzymes KatG and SodA could explain the mechanisms of antimicrobial resistance in the Cys auxotrophic mutants.
Display omitted
•cysDNC, cysJIH or cysQ loci deletion renders auxotrophy to Cys in S. Typhimurium.•cysDNC, cysJIH or cysQ mutants are less susceptible to ciprofloxacin and paraquat in S. Typhimurium.•S. Typhimurium ΔcysJIH accumulates less ROS than WT in presence of ciprofloxacin and paraquat.•Ciprofloxacin and paraquat increase expression of efflux systems in S. Typhimurium ΔcysJIH.•ΔcysJIH mutant overexpresses catalase KatG and superoxide dismutase SodA in S. Typhimurium.
Oxidative stress is the main mechanism behind efficient disinfectants, causing damage in bacterial macromolecules. Importantly, bacteria activate resistance mechanisms in response to damage generated ...by oxidative stress. Strategies allowing pathogens to survive oxidative stress are highly conserved among microorganisms. Many of these strategies entail genomic responses triggered by signals transduced through Two Component Systems (TCS). Recently, we demonstrated that the TCS ArcAB (specifically ArcA) participates in bacterial responses to hypochlorite, regulating the uptake of this toxic compound and being involved in resistance and survival inside neutrophils, where hypochlorous acid abounds. Here, we demonstrated that ArcA is required in the response to oxidative stress generated by hypochlorite, independent of its cognate sensor ArcB or the Asp54 of ArcA, the only phosphorylable residue in ArcA, which is required to function as a gene regulator. Our results suggest that ArcA could have additional functions to respond to oxidative stress, independent of its regulatory activity, which might require interaction with other unknown relevant proteins.
•ArcA is required in the response to oxidative stress generated by hypochlorite, independent of its cognate sensor ArcB.•Functionality of ArcA is independent of acetyl phosphate activity when the cell is under oxidative stress.•Our results suggest that ArcA is probably interacting with an unknown factor under the effect of Reactive Oxygen Species.
Few sclerophyllous plants from the central coast of Chile have been systematically studied. This work describes the phytochemical composition and antimicrobial properties of Baccharis concava Pers. ...(sin. B. macraei), a shrub found in the first line and near the Pacific coast. B. concava has been traditionally used by indigenous inhabitants of today’s central Chile for its medicinal properties. Few reports exist regarding the phytochemistry characterization and biological activities of B. concava. A hydroalcoholic extract of B. concava was prepared from leaves and small branches. Qualitative phytochemical characterization indicated the presence of alkaloids, steroids, terpenoids, flavonoids, phenolic, and tannin compounds. The antimicrobial activity of this extract was assessed in a panel of microorganisms including Gram-positive bacteria, Gram-negative bacteria, and pathogenic yeasts. The extract displayed an important antimicrobial effect against Gram-positive bacteria, Candida albicans, and Cryptococcus neoformans but not against Gram-negatives, for which an intact Lipopolysaccharide is apparently the determinant of resistance to B. concava extracts. The hydroalcoholic extract was then fractionated through a Sephadex LH-20/methanol–ethyl acetate column. Afterward, the fractions were pooled according to a similar pattern visualized by TLC/UV analysis. Fractions obtained by this criterion were assessed for their antimicrobial activity against Staphylococcus aureus. The fraction presenting the most antimicrobial activity was HPLC-ESI-MS/MS, obtaining molecules related to caffeoylquinic acid, dicaffeoylquinic acid, and quercetin, among others. In conclusion, the extracts of B. concava showed strong antimicrobial activity, probably due to the presence of metabolites derived from phenolic acids, such as caffeoylquinic acid, and flavonoids, such as quercetin, which in turn could be responsible for helping with wound healing. In addition, the development of antimicrobial therapies based on the molecules found in B. concava could help to combat infection caused by pathogenic yeasts and Gram-positive bacteria, without affecting the Gram-negative microbiota.
La influencia del control administrativo en los emprendedores Pizarro, Mabel Elizabeth Barriga; Lucio, Ligner Cesibel Rosel; Parrales, Raquel Aracely Asunción ...
International journal of innovation and applied studies,
06/2021, Letnik:
33, Številka:
1
Journal Article
This research focuses on the study of the importance of cost accounting for the administrative control of enterprises in Ecuador, over time, and to know what are the administrative challenges that ...must be overcome by entrepreneurs or measures they must take so that the impact of these does not affect their development and growth. Among all these factors, accounting in the company must be highlighted since it is necessary in any business model, implementing control and reaching decisions is essential to obtain results in the company. It is important that entrepreneurs possess or develop certain skills and characteristics such as leadership, creativity, decision-making, among others. To know the growth that enterprises have had in the country, a qualitative-quantitative methodology was applied, since to confirm the growth that this sector has had, it is necessary to use figures, but it is also necessary to describe the importance of administrative control by applying cost accounting in ventures, in addition to the problems that continue to affect through the descriptive method, which makes it possible to relate and conclude that entrepreneurs when they make the decision to start a business, it is appropriate to carry out previous training or develop a business plan, so that they know and carry out an analysis of the competition, who it is aimed at, who is their target market, the physical location of the premises, investment plan, suppliers and business organization.
El objetivo de este trabajo fue evaluar el efecto gastrointestinal y metabólico en un modelo murino de una botana rica en fibra (maíz, garbanzo, ajonjolí y chía) (BRF) y la comparación con el consumo ...de una botana comercial de maíz (BCM). La mezcla de maíz, garbanzo, ajonjolí y chía mejoraron la calidad nutricional del producto final a diferencia de la botana comercial. En la evaluación de la ingesta de las diferentes dietas en el modelo murino, la botana rica en fibra (BRF) disminuyó los niveles de colesterol y triglicéridos luego de 30 días de consumo, y la BCM aumentó los niveles de glucosa, provocó metaplasia en el tejido gástrico y redujo la altura de las vellosidades en el tejido del intestino delgado. La reformulación de las botanas, al utilizar además de cereales, leguminosas y oleaginosas, puede ser un alimento funcional de fácil acceso para la población, y una mejor opción que las botanas de baja calidad nutricional que se encuentran en el mercado.
The purpose of this study was to understand the manifestations of cyberviolence in the pololeo in Chilean university students. A qualitative approach was used, from the constructivist grounded ...theory. The instruments for the production of meanings were a virtual questionnaire, semi-structured interviews and focus groups, achieving the participation of 143 Chilean university students, men and women, between 20 and 25 years old.As a result, we have that cyberviolence in the pololeo is a multidimensional phenomenon, preceded mainly by jealousy, insecuri-ties and myths of romantic love. In turn, cyberviolence appears causally related to different damages in the quality of life of the victims, which translates into the affectation of their different vital areas by the perception of negative emotions, which prompts them to resort to support networks social and institutional. It is suggested to strengthen and periodically update the research on cyberviolence in the pololeo, taking into account the multidimensionality and dynamism of the phenomenon. Similarly, in future research it will be relevant to include minority and/or risk groups in adolescence, such as members of the LGBTQI+ community.
El propósito de este estudio fue comprender las manifestaciones de la ciberviolencia en el pololeo en estudiantes universitarios chilenos. Se usó una aproximación cualitativa, desde la teoría fundamentada constructivista. Los instrumentos de producción de datos consistieron en un cuestionario virtual, entrevistas semiestructuradas y grupos focales; logrando la participación de 128 estudiantes universitarios chilenos, hombres y mujeres, entre 20 y 25 años. Como resultado tenemos que la ciberviolencia en el pololeo es un fenómeno multidimensional, precedido principalmente por los celos, inseguridades y mitos del amor romántico. A su vez, la ciberviolencia aparece relacionada causalmente con diferentes perjuicios en la calidad de vida de las víctimas, lo que se traduce en la afectación de sus diferentes áreas vitales por la percepción de emociones negativas, lo que les impulsa a recurrir a redes de apoyo sociales e institucionales. Se sugiere robustecer y actualizar periódicamente la investigación respecto de ciberviolencia en el pololeo, atendiendo a la multidimensionalidad y dinamismo del fenómeno. Del mismo modo, en investigaciones futuras será relevante incluir grupos minoritarios o de riesgo en la adolescencia, como integrantes de la comunidad LGBTQI+.
The concealment, disguise or avoid knowing the origin or nature of money is considered a crime whose name is money laundering or money laundering. This subject of study that is increasing every time, ...has caused justice to intensify its regulations to combat it. In the same way has turned those who favor this activity into real cover money. Many attribute the beginnings of money laundering to Colombia, a country identified with drug trafficking, which turns out to be the main cause for this crime that significantly harms the economy of each country, being considered as a global problem. This country has taken many measures to prevent money laundering, as well as intensifying and strengthening penalties for those discovered in the crime of money laundering. These have favored its decline. In Ecuador, a neighboring country that is currently experiencing the same social and criminal problems, no preventive measures have been applied that reduce money laundering by a large percentage, facts that favor drug trafficking and other crimes so that money laundering not only increase, but intensify. In the present work we will study the current laws of the Colombian country as the Ecuadorian in an analytical and comparative way to know the aspects in which each legislation could improve.
PDF
