Inhibitory Concentration Levels Research Articles

Identification and Characterization of a Novel Chromosomal Aminoglycoside 2'-N-Acetyltransferase, AAC(2')-If, From an Isolate of a Novel Providencia Species, Providencia wenzhouensis R33.

Multidrug-resistant bacteria from different sources have been steadily emerging, and an increasing number of resistance mechanisms are being uncovered. In this work, we characterized a novel resistance gene named aac(2′)-If from an isolate of a novel Providencia species, Providencia wenzhouensis R33 (CCTCC AB 2021339). Susceptibility testing and enzyme kinetic parameter analysis were conducted to determine the function of the aminoglycoside 2′-N-acetyltransferase. Whole-genome sequencing and comparative genomic analysis were performed to elucidate the molecular characteristics of the genome and the genetic context of the resistance gene-related sequences. Among the functionally characterized resistance genes, AAC(2′)-If shares the highest amino acid sequence identity of 70.79% with AAC(2′)-Ia. AAC(2′)-If confers resistance to several aminoglycoside antibiotics, showing the highest resistance activity against ribostamycin and neomycin. The recombinant strain harboring aac(2′)-If (pUCP20-aac(2′)-If/DH5α) showed 256- and 128-fold increases in the minimum inhibitory concentration (MIC) levels to ribostamycin and neomycin, respectively, compared with those of the control strains (DH5α and pUCP20/DH5α). The results of the kinetic analysis of AAC(2′)-If were consistent with the MIC results of the cloned aac(2′)-If with the highest catalytic efficiency for ribostamycin (kcat/Km ratio = [3.72 ± 0.52] × 104 M–1⋅s–1). Whole-genome sequencing demonstrated that the aac(2′)-If gene was located on the chromosome with a relatively unique genetic environment. Identification of a novel aminoglycoside resistance gene in a strain of a novel Providencia species will help us find ways to elucidate the complexity of resistance mechanisms in the microbial population.

Identification and Characterization of a Novel Aminoglycoside 3''-Nucleotidyltransferase, ANT(3'')-IId, From Acinetobacter lwoffii.

A novel plasmid-encoded aminoglycoside 3''-nucleotidyltransferase ANT(3")-IId, was discovered in Acinetobacter lwoffi strain H7 isolated from a chick on an animal farm in Wenzhou, China. The whole-genome of A. lwoffii H7 consisted of one chromosome and five plasmids (pH7-250, pH7-108, pH7-68, pH7-48, and pH7-11). ant(3")-IId was identified as being encoded on pH7-250, sharing the highest amino acid identity of 50.64% with a function-known resistance gene, ant(3")-IIb (KB849358.1). Susceptibility testing and enzyme kinetic parameter analysis were conducted to determine the function of the aminoglycoside 3"-nucleotidyltransferase. The ant(3")-IId gene conferred resistance to spectinomycin and streptomycin [the minimum inhibitory concentration (MIC) levels of both increased 16-fold compared with the control strain]. Consistent with the MIC data, kinetic analysis revealed a narrow substrate profile including spectinomycin and streptomycin, with Kcat/Km ratios of 4.99 and 4.45×103M−1 S−1, respectively. Sequencing analysis revealed that the ant(3")-IId gene was associated with insertion sequences (IS) element [ΔISAba14-ΔISAba14-hp-orf-orf-orf1-ant(3")-IId], and ant(3")-IId were identified in plasmids from various Acinetobacter species. This study of the novel aminoglycoside 3"-nucleotidyltranferase ANT(3")-IId helps us further understand the functional and sequence characteristics of aminoglycoside 3"-nucleotidyltranferases, highlights the risk of resistance gene transfer among Acinetobacter species and suggests that attention should be given to the emergence of new aminoglycoside 3"-nucleotidyltranferase genes.

Antifungal activity and mechanism of cinnamon essential oil loaded into mesoporous silica nanoparticles

Cinnamon essential oil-mesoporous silica nanoparticles (CEO-MSNPs)/potato starch films have better antifungal activity against molds commonly found in post-harvest white mushrooms. The antifungal effects of CEO-MSNPs against Mucor sp. FJ09 species and Mucor circinelloides CNRMA 03.0371 were investigated. The antifungal mechanisms of CEO-MSNPs against molds were elucidated. Results showed that after adding CEO-MSNPs at the minimum inhibitory concentration level, there were obvious changes in membrane permeability, reactive oxygen species (ROS) content, cell component leakage, cell component leakage, soluble sugar, and malondialdehyde (MDA) content. The scanning electron microscope assay showed that CEO-MSNPs effectively destroyed the mycelial morphology of Mucor sp. FJ09 species and Mucor circinelloides CNRMA 03.0371, and interfered with their normal growth. Notably, CEO-MSNPs could be in the up-regulation of nox1 and nox2 genes of Mucor sp. FJ09 species and Mucor circinelloides CNRMA 03.0371 to generate a large number of reactive oxygen species, thereby inhibiting spore germination and growth. The results of this study could provide a reference for screening key targets of drug resistance of molds in post-harvest white mushrooms.

Exploring the possible targeting strategies of liposomes against methicillin-resistant Staphylococcus aureus (MRSA)

Multi antibiotic-resistant bacterial infections are on the rise due to the overuse of antibiotics. Methicillin-resistant Staphylococcus aureus (MRSA) is one of the pathogens listed under the category of serious threats where vancomycin remains the mainstay treatment despite the availability of various antibacterial agents. Recently, decreased susceptibility to vancomycin from clinical isolates of MRSA has been reported and has drawn worldwide attention as it is often difficult to overcome and leads to increased medical costs, mortality, and longer hospital stays. Development of antibiotic delivery systems is often necessary to improve bioavailability and biodistribution, in order to reduce antibiotic resistance and increase the lifespan of antibiotics. Liposome entrapment has been used as a method to allow higher drug dosing apart from reducing toxicity associated with drugs. The surface of the liposomes can also be designed and enhanced with drug-release properties, active targeting, and stealth effects to prevent recognition by the mononuclear phagocyte system, thus enhancing its circulation time. The present review aimed to highlight the possible targeting strategies of liposomes against MRSA bacteremia systemically while investigating the magnitude of this effect on the minimum inhibitory concentration level.

Alteration of antibiotic-resistant phenotypes and minimal inhibitory concentration of Escherichia coli in pig farming: Comparison between closed and open farming systems

The prevalence of antibiotic residues and antibiotic-resistant Escherichia coli (ARE) in closed (CSF) and open (OSF) pig farming systems was analysed. Results showed that a high level of E. coli populations, antibiotic contamination in supplied water, and additional antibiotics used, such as neomycin (NEO) or colistin (CLT), were observed in OSF. Similar ARE resistance to five antibiotics, including NEO, was observed in the water source, dung, and wastewater/sludge but were different from those of CLT. An increased occurrence of ARE was found in the sludge of anaerobic digestion (AD) and the waste stabilisation pond (WSP), but they were not well correlated with their residual antibiotic concentrations. CLT administration yielded higher ARE prevalence in pig excreta and wastewater in OSF, but its absence in CSF also resulted in ARE occurrence with increased minimal inhibitory concentration (MIC) levels in the anaerobic digester/waste stabilisation ponds. This study revealed that ARE prevalence and MIC levels of CLT could be developed during the wastewater treatment process in the pig farm, although none of the AREs were found in the original excreta/wastewater.

Silver ion doped hydroxyapatite-coated titanium pins prevent bacterial colonization.

Objectives This study aims to evaluate the effectiveness of silver ion doped calcium phosphate-based ceramic nano powder-coated titanium pins in preventing bacterial colonization.Materials and methods A total of 66 titanium pins were divided into three groups of 22 implants. The first group was coated with silver ion doped calcium phosphate-based ceramic powder by using electrospray method. The second group was coated with pure hydroxyapatite (HA), and the remaining pins were used without any coating. The remaining 22 pins were used without any coating. Staphylococcus epidermidis clinical isolate was used for the study. Each pin was placed in 1¥104 CFU/mL bacterial suspension containing tube and at 24 h quantitative culture of bacteria on the broth and on the pins were performed. Free silver ions were determined by atomic absorption method. The antibacterial culture tests were repeated on Day 2 and Weeks 2, 4, 6, and 8.Results Bacterial growth was statistically higher in broth containing uncoated pins, compared to broth media containing silver ion doped HA-coated, and pure HA-coated pins at 24 h (p=0.036 and p=0.009, respectively). The release of bacteria from silver doped HA-coated pins was statistically less, compared to pure HA-coated pins and uncoated pins (p=0.039 and p=0.002, respectively). No significant differences were observed between the HA-coated and uncoated pin groups. Minimum inhibitory concentration levels for silver ion doped powder was 8 μg/mL for coagulase-negative Staphylococcus. No free silver ions were detected in the broth media.Conclusion Silver ion doped nano size calcium phosphate-based powder-coated titanium pins reduced the bacterial colonization significantly. Using silver ion doped materials in the body can be a good option to prevent from implant related infections.

Characterization of florfenicol resistance genes in the coagulase-negative Staphylococcus (CoNS) isolates and genomic features of a multidrug-resistant Staphylococcus lentus strain H29

BackgroundWith the wide use of florfenicol to prevent and treat the bacterial infection of domestic animals, the emergence of the florfenicol resistance bacteria is increasingly serious. It is very important to elucidate the molecular mechanism of the bacteria’s resistance to florfenicol.MethodsThe minimum inhibitory concentration (MIC) levels were determined by the agar dilution method, and polymerase chain reaction was conducted to analyze the distribution of florfenicol resistance genes in 39 CoNS strains isolated from poultry and livestock animals and seafood. The whole genome sequence of one multidrug resistant strain, Staphylococcus lentus H29, was characterized, and comparative genomics analysis of the resistance gene-related sequences was also performed.ResultsAs a result, the isolates from the animals showed a higher resistance rate (23/28, 82.1%) and much higher MIC levels to florfenicol than those from seafood. Twenty-seven animal isolates carried 37 florfenicol resistance genes (including 26 fexA, 6 cfr and 5 fexB genes) with one carrying a cfr gene, 16 each harboring a fexA gene, 5 with both a fexA gene and a fexB gene and the other 5 with both a fexA gene and a cfr gene. On the other hand, all 11 isolates from seafood were sensitive to florfenicol, and only 3 carried a fexA gene each. The whole genome sequence of S. lentus H29 was composed of a chromosome and two plasmids (pH29-46, pH29-26) and harbored 11 resistance genes, including 6 genes [cfr, fexA, ant(6)-Ia, aacA-aphD, mecA and mph(C)] encoded on the chromosome, 4 genes [cfr, fexA, aacA-aphD and tcaA] on pH29-46 and 1 gene (fosD) on pH29-26. We found that the S. lentus H29 genome carried two identical copies of the gene arrays of radC-tnpABC-hp-fexA (5671 bp) and IS256-cfr (2690 bp), of which one copy of the two gene arrays was encoded on plasmid pH29-46, while the other was encoded on the chromosome.ConclusionsThe current study revealed the wide distribution of florfenicol resistance genes (cfr, fexA and fexB) in animal bacteria, and to the best of our knowledge, this is the first report that one S. lentus strain carried two identical copies of florfenicol resistance-related gene arrays.

PVA/PMMA polymer blended composite electrospun nanofibers mat and their potential use as an anti‐biofilm product

AbstractBacterial infections have increased dramatically due to microbial biofilm formation resulting in chronic pathological conditions in human subjects. Microbial biofilm causes poor drug penetration and antibiotic resistance, which has made site‐specific sustained drug delivery the most appropriate option. Our work entails fabrication of ciprofloxacin hydrochloride (CPX) loaded nanofibers using polyvinyl alcohol (PVA) and poly(meth) methacrylate (PMMA) employing electrospinning method to form PVA:PMMA:CPX nanofibers mat. These nanofibers mat were optimized, characterized, and further subjected to anti‐biofilm activity. Microscopic images revealed average nanofibers diameter of 243 ± 80 nm with smooth surface morphology. Analytical graphs and thermal analysis confirmed drug encapsulation and drug‐polymer compatibility. In vitro studies demonstrated sustained release of CPX for 22 days displaying Hixon Crowell and two‐stage desorption kinetics. Anti‐biofilm activity showed zones of inhibition 3.0 ± 0.5 cm, 2.8 ± 0.1 cm, 2.9 ± 0.2 cm for Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, respectively which was well above the minimum inhibitory concentration levels of the bacteria forming biofilm. Conclusively, these nanofibers mat have potential to be used as an anti‐biofilm product.

A Cationic Porphyrin, ZnPor, Disassembles Pseudomonas aeruginosa Biofilm Matrix, Kills Cells Directly, and Enhances Antibiotic Activity of Tobramycin.

One of the greatest threats to human health is the rise in antibiotic-resistant bacterial infections. Pseudomonas aeruginosa (PsA) is an “opportunistic” pathogen known to cause life-threatening infections in immunocompromised individuals and is the most common pathogen in adults with cystic fibrosis (CF). We report here a cationic zinc (II) porphyrin, ZnPor, that effectively kills planktonic and biofilm-associated cells of PsA. In standard tests against 16–18 h-old biofilms, concentrations as low as 16 µg/mL resulted in the extensive disruption and detachment of the matrix. The pre-treatment of biofilms for 30 min with ZnPor at minimum inhibitory concentration (MIC) levels (4 µg/mL) substantially enhanced the ability of tobramycin (Tobra) to kill biofilm-associated cells. We demonstrate the rapid uptake and accumulation of ZnPor in planktonic cells even in dedicated heme-uptake system mutants (ΔPhu, ΔHas, and the double mutant). Furthermore, uptake was unaffected by the ionophore carbonyl cyanide m-chlorophenyl hydrazine (CCCP). Cells pre-exposed to ZnPor took up the cell-impermeant dye SYTOXTM Green in a concentration-dependent manner. The accumulation of ZnPor did not result in cell lysis, nor did the cells develop resistance. Taken together, these properties make ZnPor a promising candidate for treating multi-drug-resistant infections, including persistent, antibiotic-resistant biofilms.

Valsartan solid lipid nanoparticles integrated hydrogel: A challenging repurposed use in the treatment of diabetic foot ulcer, in-vitro/in-vivo experimental study

The article presents an experimental study on the possible repurposed use of valsartan (Val), in the local treatment of uncontrolled diabetic foot ulcer. Solid lipid nanoparticles (SLN), loaded with Val were prepared by applying 32 full factorial design using modified high shear homogenization method. The lipid phase composed of Precirol® ATO 5 (P ATO 5) and/or Gelucire 50/13 (G 50/13) in different ratios and a nonionic emulsifier, Pluronic 188 (P188), was used in different percentages. Optimized formulation was further integrated in hydroxyl propyl methyl cellulose (HPMC) gel for the ease of administration. In-vitro and in-vivo characterizations were investigated. The prepared nanoparticles showed small particle size, high entrapment efficiency and sustained drug release. Microbiologically, Val-SLN showed a prominent decrease in the biofilm mass formation for both gram-positive and gram-negative bacteria, as well as a comparable minimum inhibitory concentration level to levofloxacin alone. Diabetes was induced in 32 neonatal Sprague-Dawley rats. At 8 weeks of age, rats with blood sugar level >160 were subjected to surgically induced ulcer. Treatment with Val-SLN for 12 days revealed enhanced healing characteristics through cyclooxygenase-2 (COX-2), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), nitric oxide (NO), transforming growth factor-beta (TGF-β), matrix metalloproteinase (MMPs) and vascular endothelial growth factor (VEGF) pathways. Histological examination revealed re-epithelization in Val-SLN treated ulcer, as well as decrease in collagen using trichrome histomorphometric analysis.

Effects of disinfectants and ciprofloxacin on quorum sensing genes and biofilm of clinical Pseudomonas aeruginosa isolates

BackgroundPseudomonas aeruginosa is one of the most virulent bacteria and quorum sensing (QS) genes have an importance on virulence factors such as biofilm that provide resistance against disinfectants and antibiotics. ObjectiveThis study aimed to determine the minimum inhibitory concentrations of the disinfectants, to investigate the effects of disinfectants and ciprofloxacin on biofilm production mature biofilm of clinical P. aeruginosa isolates, and it was aimed to investigate the effects of the agents on the expression levels of several QS-related genes in the isolates. MethodsMinimum inhibitory concentration (MIC) levels of polyhexamethylene biguanide (PHMB), chlorhexidine (CHX), quaternary ammonium compounds (QAC), glutaraldehyde (GLU) and ciprofloxacin (CIP) against clinical P. aeruginosa isolates were evaluated by microdilution method. Effects of the agents on the biofilm producing capacities of clonally unrelated nine strains were investigated by spectrophotometric method. Alterations in the expression of QS-related genes (lasI, lasR, rhlI and rhlR) were investigated by qPCR in three isolates that were CIP-susceptible and strong biofilm producer. ResultsAccording to microdilution method results, three isolates were found as resistant, one isolate was found as intermediate susceptible and five isolates were found as susceptible to CIP, and CHX (7.81–31.25 μg/mL) had the lowest MIC against P. aeruginosa. CHX inhibited biofilm production levels of eight of nine isolates, and GLU and CIP inhibited six of nine isolates in the presence of agents at MIC levels. GLU inhibited the mature biofilm levels of three of nine isolates at MIC and MIC/4 levels and four of nine isolates at MIC/2 levels. Expression levels of QS-related genes were reduced or induced in the presence of different disinfectants. ConclusionsMore efforts are required to decrease the risk of ineffective and low-dose application of disinfectants and antimicrobials against bacteria. Targeting of QS-related genes may be a reasonable strategy for the inhibition of virulence factors in P. aeruginosa.

Nano-strategies in pursuit of efflux pump activeness in Acinetobacter baumannii and Pseudomonas aeruginosa

Multidrug-resistant Acinetobacter baumannii and Pseudomonas aeruginosa are the two bacteria notorious for nosocomial infections and threats in healthcare settings. Efflux pump is an important mechanism of the antibiotic resistant phenomenon. The emergence of antibiotic-resistant bacteria demands the development of either new antibacterial agents to overcome the distressing situation. The aim of this study was to evaluate the efficacy of chitosan and silver (Ag) nanoparticles (NPs) and their combination with antibiotics to alter the expression level of efflux pumps and any increase in the inhibitory capacity of antibiotics against clinical A.baumannii and P.aeruginosa isolates. To conduct the experiments, initially antibiotic resistant A. baumannii and P. aeruginosa (PAO1) strains were exposed to chitosan and AgNPs with and without ciprofloxacin and gentamicin in their sub inhibitory levels. RNA was then extracted to study the antibacterial effects of the nanoparticles in relation to the expression of the efflux pump using real-time PCR. The present investigation found expression levels of abeM efflux pumps in A.baumannii and mexY efflux pumps in P.aeruginosa decreased after exposing the bacteria to sub-inhibitory concentrations of chitosan, chitosan NPs, and their combination with ciprofloxacin and gentamicin. Conversely, the minimum inhibitory concentration (MIC) levels of ciprofloxacin and gentamicin were found to have increased after exposure to the synthetic substances. Though nanoparticles have found their place in the modern scientific therapeutic world however, before they step into treatment strategies it is necessary to determine their effects either alone or with antibiotics in lowering antibiotic resistance.

Determination of the inhibitory concentration level of fat, oil, and grease (FOG) towards bacterial and archaeal communities in anaerobic digestion

Full-scale application of anaerobic digestion (AD) of any substrate is made possible through identifying its impact in terms of biomethane inhibition and optimum levels along with degradation and microbial community composition. This study focused on utilisation of FOG in AD by investigating varying FOG amounts to determine optimum and inhibitory concentration levels; in addition, we also studied its effect on microbial populations and biomethane production. Increased FOG levels extended the lag phase and eventually displayed complete inhibition. Operating AD with FOG levels in the concentration range of 0.1–1.5% (v/v) enhanced biomethane production, resulting in a 2 to 19-fold increase. The highest biomethane production was observed at 1% FOG (19-fold increase), with a lag phase of 25 days. LCFAs were degraded by 80–90% during AD, following a 0.5–1.5% FOG loading. An addition of either 2 or 3% FOG permanently inhibited biomethane production due to high VFA accumulation (17–19 g/L) and low LCFA reduction (29 and 18%), respectively. Under optimum biomethane production (1–1.5% FOG), Syntrophomonas and Fermentimonas were abundant, indicating their role in LCFA degradation and acetogenesis. Methanosaeta archaea were initially dominant, owing to the increased presence of LCFAs, but were replaced by Methanosarcina after the conversion of LCFAs to acetate and other acids. The current study proposes to run AD at around 1% (v/v) FOG loading to achieve maximum yield. To avoid inhibition during high FOG loadings (>1.5%), this would require microbial acclimatisation or prior substrate treatment.

Minimum bactericidal concentration of ciprofloxacin to Pseudomonas aeruginosa determined rapidly based on pyocyanin secretion

Infections due to Pseudomonas aeruginosa (P. aeruginosa) often exhibit broad-spectrum resistance and persistence to common antibiotics. Persistence is especially problematic with immune-compromised subjects who are unable to eliminate the inhibited bacteria. Hence, antibiotics must be used at the appropriate minimum bactericidal concentration (MBC) rather than at minimum inhibitory concentration (MIC) levels. However, MBC determination by conventional methods requires a 24 h culture step in the antibiotic media to confirm inhibition, followed by a 24 h sub-culture step in antibiotic-free media to confirm the lack of bacterial growth. We show that electrochemical detection of pyocyanin (PYO), which is a redox-active bacterial metabolite secreted by P. aeruginosa, can be used to rapidly assess the critical ciprofloxacin level required for bactericidal deactivation of P. aeruginosa within just 2 h in antibiotic-treated growth media. The detection sensitivity for PYO can be enhanced by using nanoporous gold that is modified with a self-assembled monolayer to lower interference from oxygen reduction, while maintaining a low charge transfer resistance level and preventing electrode fouling within biological sample matrices. In this manner, bactericidal efficacy of ciprofloxacin towards P. aeruginosa at the MBC level and bacterial persistence at the MIC level can be determined rapidly, as validated at later timepoints using bacterial subculture in antibiotic-free media.

Targeting bedaquiline mycobacterial efflux pump to potentially enhance therapy in Mycobacterium abscessus.

Mycobacterium abscessus is notorious for being intrinsically resistant to most antibiotics. Antibiotic efflux is one of the mechanisms used by M. abscessus to pump out antibiotics from their cells. Inhibiting efflux pumps (EPs) can be an attractive strategy to enhance the activity of drugs. The objective of this study is to determine the activity of EP inhibitors (EPIs) to enhance the efficacy of the new drug bedaquiline against M. abscessus clinical isolates. A total of 31 phenotypically and genotypically identified M. abscessus subsp. abscessus, M. abscesss subsp. massiliense, and M. abscessus subsp. bolletii clinical isolates were studied. The contribution of EPs was determined by investigating the minimum inhibitory concentration (MIC) levels of bedaquiline reduction in the absence and presence of EPIs verapamil and reserpine using the resazurin microtiter assay. The observed bedaquiline MIC reduction by verapamil was observed in 100% isolates and by reserpine in 54.8% isolates. Bedaquiline MIC was 4-32-fold using verapamil with M. abscessus subsp. bolletii showing the highest fold change and between 2- and 4-fold using reserpine. The results obtained in this study confirm that bedaquiline MIC decreased in the presence of EPIs verapamil and reserpine in clinical isolates of M. abscessus. Verapamil was the most effective EPI. As shown in previous studies, verapamil may have clinical potential as adjunctive therapy to enhance the effect of bedaquiline.

<i>Weissella cibaria</i> CMU suppresses <i>mgl</i> gene expression and enzyme activity associated with bad breath

The oral care probiotic strain Weissella cibaria CMU (oraCMU) inhibits volatile sulphur compounds associated with halitosis, presumably by inhibiting the growth of associated oral pathogens. In the present study, we investigated whether oraCMU inhibits the production of these compounds by suppressing the expression of mgl . This gene encodes L-methionine-α-deamino-γ-mercaptomethane-lyase (METase) and is involved in the production of methyl mercaptan (CH3SH) by Porphyromonas gingivalis . Therefore, we specifically investigated the effects of oraCMU on the growth, CH3SH production, METase activity, and mgl expression of P. gingivalis . The minimum inhibitory concentrations of cell-free supernatant and secreted proteins from oraCMU were 125 mg/mL and 800 µg/mL, respectively. At sub-minimum inhibitory concentration levels, these metabolites inhibited CH3SH production, but they also reduced P. gingivalis viability. Only heat-killed oraCMU decreased CH3SH production without affecting P. gingivalis viability. Heat-killed oraCMU also inhibited METase activity toward L-methionine and mgl mRNA expression (p < 0.05). In summary, we demonstrated the inhibition of volatile sulphur compounds via the antimicrobial action of oraCMU and, for the first time, the inhibition of such compounds by heat-killed oraCMU, which occurred at the molecular level.

Comparison of physicochemical, mechanical and antioxidant properties of polyvinyl alcohol films containing green tealeaves waste extracts and discarded balsamic vinegar

Abstract Plant origin processed food wastes like tealeaves, coffee, fruit or wine pomace can be very rich in antioxidants and antiseptics. The goal of this work is to develop antioxidant polyvinyl alcohol (PVA) packaging films using wastes generated from used green tealeaves and discarded (quality control failed) balsamic vinegar and compare their properties. Both components were separately incorporated into PVA via simple one-pot fabrication approach. Formic acid was used to extract potential antioxidants from dried waste tealeaves, simultaneously dissolving PVA. Discarded vinegar was simply added to a water solution of PVA and in both cases antioxidant films were produced by solution casting and drying. PVA films were loaded up to 50 wt.% by both waste components allowing maximum utilization of useful organics from both discarded foodstuffs. Formic acid extracted gallated catechins with very high yields (>95 %) from tealeaves waste with excess amounts of epigallocatechin gallate (EGCG). Moreover, discarded balsamic vinegar was found to be an effective plasticizer for PVA with 150 % elongation levels. Tealeaves waste exhibited better inhibitory concentration levels (IC50; 73.1 μg/ml) than discarded balsamic vinegar (1846.7 μg/mL), comparable to synthetic commercial antioxidants. They also improved oxygen barrier properties of PVA, regardless of the solvent used. These films could be potentially suitable for antioxidant food packaging applications.

Genome Assemblies of Two Rare Opportunistic Yeast Pathogens: Diutina rugosa (syn. Candida rugosa) and Trichomonascus ciferrii (syn. Candida ciferrii).

Infections caused by opportunistic yeast pathogens have increased over the last years. These infections can be originated by a large number of diverse yeast species of varying incidence, and with distinct clinically relevant phenotypic traits, such as different susceptibility profiles to antifungal drugs, which challenge diagnosis and treatment. Diutina rugosa (syn. Candida rugosa) and Trichomonascus ciferrii (syn. Candida ciferrii) are two opportunistic rare yeast pathogens, which low incidence (< 1%) limits available clinical experience. Furthermore, these yeasts have elevated Minimum Inhibitory Concentration (MIC) levels to at least one class of antifungal agents. This makes it more difficult to manage their infections, and thus they are associated with high rates of mortality and clinical failure. With the aim of improving our knowledge on these opportunistic pathogens, we assembled and annotated their genomes. A phylogenomics approach revealed that genes specifically duplicated in each of the two species are often involved in transmembrane transport activities. These genomes and the reconstructed complete catalog of gene phylogenies and homology relationships constitute useful resources for future studies on these pathogens.

Synthesis and Evaluation of Biological Activity of Homodrimane Sesquiterpenoids Bearing Hydrazinecarbothioamide or 1,2,4-Triazole Unit

Synthesis of novel (+)-sclareolide-based homodrimane sesquiterpenoids bearing hydrazinecarbothioamide or N-substituted 1,2,4-triazole unit has been reported. These heterocyclic compounds demonstrate promising in vitro antifungal and antibacterial activities toward fungal species Aspergillus niger, Fusarium solani, Penicillium chrysogenum, Penicillium frequentans, and Alternaria alternata and bacteria strains Bacillus sp. and Pseudomonas aeruginosa at minimum inhibitory concentration level of μg/ml. In addition, two homodrimane sesquiterpenoids with hydrazinecarbothioamide fragment show cytotoxicity toward human ovarian carcinoma cells A2780 and A2780cis with half maximal inhibitory concentration values in range of 9–15 μM.

Anti-Mesothelin Recombinant Immunotoxin Therapy for Colorectal Cancer

BackgroundMesothelin (MSLN) is a cell surface glycoprotein expressed at a high level on many malignancies, including pancreatic adenocarcinoma, serous ovarian cancer, and epithelioid mesothelioma. MSLN-targeted recombinant immunotoxins (RITs) consist of an anti-MSLN Fv fused to the catalytic domain of Pseudomonas exotoxin A. Recent data has also shown that MSLN is expressed at clinically relevant levels on the surface of colorectal cancer (CRC). In this study, CRC cell lines were tested for MSLN expression and susceptibility to MSLN-targeted RITs. Materials and MethodsCRC cell lines were tested for membranous MSLN expression via flow cytometry. Cell lines expressing MSLN were tested by WST-8 cell viability assay for sensitivity to various RITs and chemotherapeutic agents. CRC cell line SW-48 was tested in a mouse model for response to RIT as a single agent or in combination with actinomycin D and oxaliplatin. ResultsCRC cell lines were susceptible to anti-MSLN RITs at half maximal inhibitory concentration levels comparable with those previously described in pancreatic cancer cell lines. In a nude mouse model, MSLN-targeted RIT treatment of SW48 CRC tumors resulted in a significant decrease in tumor volume. Although combination therapy with standard of care chemotherapeutic oxaliplatin did not improve tumor regressions, combination therapy with actinomycin D resulted in > 90% tumor volume reduction with 50% complete regressions. ConclusionsThese data support the development of anti-MSLN RITs as well as other MSLN-targeted therapies for CRC.