Search

Research describes a method to develop vectors for sequential integration of new functions into Escherichia coli chromosomes. Results demonstrate that such vectors aid in precise deletion of unwanted genes during integration of E. coli chromosomes with DNA from different bacterial systems.

Dactylopius opuntiae is an insect pest that contains at least carminic acid, which has antioxidant properties. Since there is a relationship between the antioxidant ability and preservative action of compounds applied to meat products, the purpose of this study was to evaluate the antioxidant activity and usefulness of a D. opuntiae extract for beef patty preservation. The insects were bred and processed to obtain a liquid extract. For the extract, its carminic acid content, antioxidant activity against two free radicals, and actions on food quality parameters were determined. The D. opuntiae dry powder contained 2.91% w/w carminic acid, while the liquid extract exhibited an IC50 value of 3437.8 ± 67.8 and 19633.0 ± 674.5 µg/mL against the DPPH and ABTS radicals. Nevertheless, these antioxidant actions were lower than those found in a D. coccus extract. The D. opuntiae extract improved in a short time the redness and yellowness, eliminated the unfavorable effect of their vehicle on the MetMb level, and greatly reduced the TBARS formation. For the first time, an extract of D. opuntiae was applied to beef patties, and its beneficial antioxidant action on meat acceptance parameters was confirmed, which has potential commercial applications.

The adjunctive use of fluoroquinolone (FQ) agents in patients with periodontitis produces contradictory results. There has been no meta-analysis performed based on the evaluations of FQ use that would enable making appropriate clinical decisions. Our study aimed to evaluate, via a systematic review and metaanalysis conducted in accordance with the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines, the clinical benefits, antimicrobial effects and safety profiles of the FQ agents administered to periodontitis patients under a conventional treatment regime. Relevant databases were searched for studies published up to May 2020, with the quality and risk of bias evaluations performed on the selected studies, and meta-analyses, funnel plots and heterogeneity tests carried out based on the obtained data. Any finding of p-value less than 0.05 was considered statistically significant. Quality and the risk of bias ranged from high to low. With acceptable heterogeneity and no reporting bias, the meta-analyses showed that local or systemic FQ use produced the following results: a reduced probing depth change (ΔPD) (p < 0.00001 at ≤3 months); reduced bleeding on probing (BOP) (p < 0.00001 at 3-6 months); reduced subgingival detection of Aggregatibacter actinomycetemcomitans for up to 12 months (p-values from <0.00001 to 0.001); and an insignificant number of adverse events (p ≥ 0.05) in patients subjected to a conventional therapy as compared to those subjected to an antibiotic-free therapy. Our study found evidence to show that FQ administration provides clinical benefits and ensures antibacterial effects in periodontitis patients subjected to a conventional therapy regime.

Fluoroquinolone agents are used widely for the treatment of infectious diseases which are a common cause of deaths around the world. The level of oxidative stress in patients taking fluoroquinolone antibiotics has not been considered a factor to reduce the clinical efficacy of this kind of drugs. Patients with diabetes and/or cardiovascular diseases present abnormal levels of oxidative stress in the blood stream. In this regards, our hypothesis supposes that patients with diabetes and/or cardiovascular disease suffering a bacterial disease could experience a therapeutic failure and bacterial resistance when treated with fluoroquinolones. The crucial mechanism could be an inefficient blood distribution of the drug via red blood cell dysfunction induced by oxidative stress that might reduce the pharmacokinetic-pharmacodinamic ratios. In this way, we review the scientific information to support our hypothesis alongside possible implications. Additionally, this work exhibits the urgent need of studies considering these conditions for quinolone agents., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Objectives: Levofloxacin monitoring is recommended to obtain clinical cure and low incidence of antimicrobial resistance. During the monitoring procedure, levofloxacin should be measured in plasma samples and several assays are reported for this purpose. However, those methods do not have all of the characteristics for an accessible and reliable drug monitoring. For this reason, we develop a method that has all of the essential characteristics for levofloxacin monitoring., Design and Methods: The procedure of validation was done in terms of Food and Drug Administration guidelines. Subsequently, our assay was applied in plasma samples obtained from healthy volunteers with a single oral administration of levofloxacin as well as patients with respiratory diseases under levofloxacin therapy., Results: Levofloxacin was extracted from samples using only two precipitation steps. Our assay had a rapid run time (5min), adequate sensitivity (0.05μg/ml of lower limit of quantification), and acceptable parameters of validation. Moreover, compound identities were supported using three dimensional spectra and purities were confirmed employing similarity factors (values>900). Variable concentrations of levofloxacin in samples were observed during the application., Conclusions: Levofloxacin is successfully quantified using our method that shows reliable results, appropriate range, rapid analyses, and cost-effective measurements under a simple and easy technique while all prior methods did not have it all together. Consequently, our method is a valuable tool for routine drug monitoring. Moreover, a complete evaluation of specificity was done for levofloxacin in plasma samples for the first time. Meanwhile, the application data supported the necessity of levofloxacin monitoring., (Copyright © 2016 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.)

Due to the great global concern regarding bacterial resistance to antibiotics, an ongoing search for new molecules having antibacterial activity is necessary. This study evaluated the antibacterial and anticandidal effects of a hexane extract from the root of Salvia apiana. Salvia extracts at concentrations of 27, 13.5, 6.8 and 3.4mg/ml caused growth inhibition of Staphylococcus aureus, Streptococcus pyogenes, Enterococcus faecalis and Candida albicans. However, no significant effect was observed on Escherichia coli and Candida tropicalis in comparison to vehicle. It was here demonstrated for the first time that Salvia apiana has an important antimicrobial effect on human pathogens of great clinical value, thus opening the field to continue the evaluation of this lamiaceous plant for its future use as a therapeutic agent., (Copyright © 2016 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.)

Hyperpolarization-activated cationic and cyclic nucleotide-gated channels (HCN) comprise four homologous subunits (HCN1-HCN4). HCN channels are found in excitable and non-excitable tissues in mammals. We have previously shown that HCN2 may transport ammonium (NH4 (+)), besides sodium (Na(+)), in the rat distal nephron. In the present work, we identified HCN1 and HCN3 in the proximal tubule (PT) and HCN3 in the thick ascending limb of Henle (TALH) of the rat kidney. Immunoblot assays detected HCN1 (130 kDa) and HCN3 (90 KDa) and their truncated proteins C-terminal HCN1 (93 KDa) and N-terminal HCN3 (65 KDa) in enriched plasma membranes from cortex (CX) and outer medulla (OM), as well as in brush-border membrane vesicles. Immunofluorescence assays confirmed apical localization of HCN1 and HCN3 in the PT. HCN3 was also found at the basolateral membrane of TALH. We evaluated chronic changes in mineral dietary on HCN3 protein abundance. Animals were fed with three different diets: sodium-deficient (SD) diet, potassium-deficient (KD) diet, and high-potassium (HK) diet. Up-regulation of HCN3 was observed in OM by KD and in CX and OM by HK; the opposite effect occurred with the N-terminal truncated HCN3 in CX (KD) and OM (HK). SD diet did not produce any change. Since HCN channels activate with membrane hyperpolarization, our results suggest that HCN channels may play a role in the Na(+)-K(+)-ATPase activity, contributing to Na(+), K(+), and acid-base homeostasis in the rat kidney.

The ATP-related compounds in whole blood or red blood cells have been used to evaluate the energy status of erythrocytes and the degradation level of the phosphorylated compounds under various conditions, such as chronic renal failure, drug monitoring, cancer, exposure to environmental toxics, and organ preservation. The complete interpretation of the energetic homeostasis of erythrocytes is only performed using the compounds involved in the degradation pathway for adenine nucleotides alongside the uric acid value. For the first time, we report a liquid chromatographic method using a diode array detector that measures all of these compounds in a small human whole blood sample (125 μL) within an acceptable time of 20 min. The stability was evaluated for all of the compounds and ranged from 96.3 to 105.1% versus the day zero values. The measurement had an adequate sensitivity for the ATP-related compounds (detection limits from 0.001 to 0.097 μmol/L and quantification limits from 0.004 to 0.294 μmol/L). This method is particularly useful for measuring inosine monophosphate, inosine, hypoxanthine, and uric acid. Moreover, this assay had acceptable linearity (r > 0.990), precision (coefficients of variation ranged from 0.1 to 2.0%), specificity (similar retention times and spectra in all samples) and recoveries (ranged from 89.2 to 104.9%). The newly developed method is invaluable for assessing the energetic homeostasis of red blood cells under diverse conditions, such as in vitro experiments and clinical settings.

The function of phosphatidylcholine (PC) in the bacterial cell envelope remains cryptic. We show here that productive interaction of the respiratory pathogen Legionella pneumophila with host cells requires bacterial PC. Synthesis of the lipid in L. pneumophila was shown to occur via either phospholipid N-methyltransferase (PmtA) or phosphatidylcholine synthase (PcsA), but the latter pathway was demonstrated to be of predominant importance. Loss of PC from the cell envelope caused lowered yields of L. pneumophila within macrophages as well as loss of high multiplicity cytotoxicity, while mutants defective in PC synthesis could be complemented either by reintroduction of PcsA or by overproduction of PmtA. The lowered yields and reduced cytotoxicity in mutants with defective PC biosynthesis were due to three related defects. First, there was a poorly functioning Dot/Icm apparatus, which delivers substrates required for intracellular growth into the cytosol of infected cells. Second, there was reduced bacterial binding to macrophages, possibly due to loss of PC or a PC derivative on the bacterium that is recognized by the host cell. Finally, strains lacking PC had low steady-state levels of flagellin protein, a deficit that had been previously associated with the phenotypes of lowered cytotoxicity and poor cellular adhesion.