The <i>Staphylococcus aureus</i> toxin–antitoxin system YefM–YoeB is associated with antibiotic tolerance and extracellular dependent biofilm formation

The high antibiotic tolerance of Staphylococcus aureus biofilms is associated with challenges for treating periprosthetic joint infection. The toxin–antitoxin system, YefM–YoeB, is thought to be a regulator for antibiotic tolerance, but its physiological role is unknown. The objective of this study was to determine the biofilm and antibiotic susceptibility phenotypes associated with S. aureus yoeB homologs. We hypothesized the toxin–antitoxin yoeB homologs contribute to biofilm formation and antibiotic susceptibility. Disruption of yoeB1 and yoeB2 resulted in decreased biofilm formation in comparison to Newman and JE2 wild-type (WT) S. aureus strains. In comparison to yoeB mutants, both Newman and JE2 WT strains had higher polysaccharide intercellular adhesin (PIA) production. Treatment with sodium metaperiodate increased biofilm formation in Newman WT, indicating biofilm formation may be increased under conditions of oxidative stress. DNase I treatment decreased biofilm formation in Newman WT but not in the absence of yoeB1 or yoeB2. Additionally, WT strains had a higher extracellular DNA (eDNA) content in comparison to yoeB mutants but no differences in biofilm protein content. Moreover, loss of yoeB1 and yoeB2 decreased biofilm survival in both Newman and JE2 strains. Finally, in a neutropenic mouse abscess model, deletion of yoeB1 and yoeB2 resulted in reduced bacterial burden. In conclusion, our data suggest that yoeB1 and yoeB2 are associated with S. aureus planktonic growth, extracellular dependent biofilm formation, antibiotic tolerance, and virulence.

Production of Carboxymethyl Starches from Oxidized Starches and Determination of Their Tanning Characteristics

Hydrogen peroxide and sodium metaperiodate oxidation of starch and their possible utilization in tanning/retanning were examined in our previous studies. In the present part, accordingly with our previous findings, hydrogen peroxide and sodium metaperiodate oxidation products having appropriate molecular weight/size were selected and additionally carboxymethylated. The yields of the processes (carboxymethyl starches) were characterized comprehensively and the effect of carboxymethylation process on structures and tanning abilities were tried to be identified. The characterization results revealed that the carboxymethyl groups were successfully included into the structure and the water solubility of oxidized starches (especially periodate oxidized ones) increased by carboxymethylation process. From the evaluation of the tanning results and considering its properties i.e. gentle tanning effect with less astringency and correspondingly a relatively soft leather handle and smooth grain, it is concluded that dialdehyde carboxymethyl starch (CMS 1:0.7) can be utilized as yet another good alternative sustainable green tanning/retanning agent from starch.

Covalent Immobilization of Lipase in Residual Yerba Mate Stick (Ilex paraguariensis A. St.-Hil.)

The objective of this study was to immobilize Eversa® Transform 2.0 lipase on residual yerba mate stick. The stick went through an alkaline pre-treatment and different activation treatments (APTS/glutaraldehyde and sodium metaperiodate). Immobilization was performed using hexane solvent and ammonium nitrate buffer. Support characterization, esterification activity, immobilized enzyme characterization, and operational stability were performed. Characterization by SEM demonstrated that the activation treatments were efficient. The immobilization of lipase on APTS/glutaraldehyde activated support showed a yield of 225.52 % and metaperiodate 162.76 %, using hexane as solvent. Good operational stability of the immobilized lipase was observed both in support activated with APTS / glutaraldehyde (8 recycles) and in support activated with metaperiodate (5 recycles), maintaining the activity of 65.62% and 52.00% in concern to the activity initial, respectively. The optimal reaction temperature was 40 ºC for the free and immobilized enzyme. Km and Vmáx values were 16.55 μmol.g-1 and 5555.56 μmol.g-1.min-1 for free enzyme; 33.52 μmol.g-1 and 4761.9 μmol.g-1.min-1 for immobilized enzyme, respectively. The parameters of thermal inactivation confirmed a better thermostability of the lipase in free form.

Alternative Tanning Agent for Leather Industry from a Sustainable Source

Dialdehyde starches with different aldehyde content from native corn starch were prepared by sodium periodate oxidation to be used as a tanning agent in leather making. For this purpose, native corn starch was oxidized with sodium metaperiodate in different molar ratios. After oxidation processes, the yields, solubility in water and aldehyde contents of the obtained dialdehyde starches were determined as well as structure characterizations by Proton Nuclear Magnetic Resonance Spectroscopy, Fourier Transform Infrared Spectroscopy and Gel Permeation Chromatography. Evaluating the gel permeation chromatography data, the dialdehyde starch samples which were thought to be in appropriate molecular weight/size to penetrate into skin fibers were selected to be used in the tanning process. Their tanning abilities were evaluated by investigating hydrothermal stabilities, filling and fiber isolation characteristics and physical properties determined by mechanical tests and organoleptically. From the evaluation of the results, it was revealed that sodium metaperiodate oxidized starches which have appropriate molecular weight and adequate aldehyde content has a remarkable tanning effect and can be utilized as a tanning agent with the advantages of not necessitating pickling process which means saving time and simplifying the production but more importantly offering an important advantage from an environmental point of view.

IgG reactivity profile to Paracoccidioides spp. antigens in people with asymptomatic Paracoccidioidomycosis

Introduction. Paracoccidioidomycosis (PCM) is a systemic mycosis caused by Paracoccidioides spp. As the disease is known to affect mostly men over 40 years old who previously worked handling soil, some cities of agricultural economy in endemic regions may have more cases of paracoccidioidal infection. Gap statement. The true frequency of PCM cannot be established in Brazil because it is not a disease of mandatory reporting. The detection of paracoccidioidal infection may assist in the planning of health services, in order to provide early detection of the disease and to prevent its worsening or even progression to death. In addition, little is described about sera reactivity with antigens from different species of Paracoccidiodes, especially P. lutzii. Aim. Current research was conducted in an inland municipality of southern Brazil, in order to assess infection rate within this endemic region of PCM disease. Methodology. ELISA was employed to evaluate 359 sera from random volunteers from Guarapuava, Paraná, Brazil, to detect IgG against cell-free antigens (CFA) from P. restrepiensis B339, P. americana LDR3 and P. lutzii LDR2. Confirmatory ELISA employed gp43 from B339. Reduction of cross-reactions was sought by treatment with sodium metaperiodate (SMP-CFA, SMP-gp43). Immunoblot was performed with 37 selected sera among those reactive in ELISA. Epidemiological profile was assessed by questionnaire. Results. ELISA reactivity was: CFA/SMP-CFA in general 37.3/17.8 %, B339 25.3/14.5 %, LDR3 24.5/1.4 %, LDR2 8.3/5.8 %; gp43/SMP-gp43 7.2/4.7 %. There were sera reactive with multiple CFAs. In immunoblot, five sera showed the same reaction profile with P. lutzii’s antigens as PCM disease sera. Rural residence and soil-related professions were risk factors for paracoccidioidal infection. Conclusion. The low prevalence is in accordance with previous reports of lower PCM disease endemicity in Guarapuava than in other areas of Paraná. Although P. brasiliensis seems to be the prevalent strain of the region, 21 sera from people who only lived in Guarapuava reacted with P. lutzii LDR2. CFA-ELISA with whole antigens seems a good option for serological screening in epidemiological surveys.

A Whey Fraction Rich in Immunoglobulin G Combined with Bifidobacterium longum subsp. infantis ATCC 15697 Exhibits Synergistic Effects against Campylobacter jejuni

Evidence that whey proteins and peptides have health benefits beyond basic infant nutrition has increased dramatically in recent years. Previously, we demonstrated that a whey-derived immunoglobulin G-enriched powder (IGEP) enhanced adhesion of Bifidobacterium longum subsp. infantis ATCC 15697 (B. infantis) to HT-29 cells. In this study, we investigated the synergistic effect of IGEP-treated B. infantis on preventing the attachment of highly invasive Campylobacter jejuni 81–176 (C. jejuni) to intestinal HT-29 cells. The combination decreased the adherence of C. jejuni to the HT-29 cells by an average of 48% compared to the control (non-IGEP-treated B. infantis). We also confirmed that treatment of IGEP with sodium metaperiodate, which disables the biological recognition of the conjugated oligosaccharides, reduced adhesion of B. infantis to the intestinal cells. Thus, glycosylation of the IGEP components may be important in enhancing B. infantis adhesion. Interestingly, an increased adhesion phenotype was not observed when B. infantis was treated with bovine serum-derived IgG, suggesting that bioactivity was unique to milk-derived immunoglobulin-rich powders. Notably, IGEP did not induce growth of B. infantis within a 24 hours incubation period, as demonstrated by growth curves and metabolite analysis. The current study provides insight into the functionality of bovine whey components and highlights their potential in positively impacting the development of a healthy microbiota.

Spectrophotometric Determination of Mesalazine in Pharmaceutical Preparations by Oxidative Coupling Reactions with m-Aminophenol and 2,6- Dihydroxybenzoic Acid

Tow simple, rapid and sensitive spectrophotometric methods for the determination of mesalazine in pharmaceutical preparations have been carried out. The proposed methods depend on oxidative coupling reaction of mesalazine with m-aminophenol in the existence of N-bromosuccinamide in alkaline medium (method A) and 2,6-dihydroxybenzoic acid in the existence of sodium metaperiodate in basic medium (method B) to produce colored products , show highest absorptions at 640 (nm) and 515 (nm), alternately. Beer’s law was consistent in concentrations extent of 1.25-30 and 0.5-12.5 (µg.mL-1) with molar absorptivity of 0.36×104 and 0.77×104 L.mol-1.cm-1, alternately. The limits of detection (LOD) were 0.0144 and 0.0829 µg.mL-1, while limits of quantitation (LOQ) were 0.0483 and 0.2766 (µg.mL-1), alternately. The suggested methods have been applied successfully to the determination of mesalazine in its pharmaceutical preparations as tablets and suppositories.

A Trypsin-Sensitive Proteoglycan from the Tapeworm Hymenolepis diminuta Inhibits Murine Neutrophil Chemotaxis in vitro by Suppressing p38 MAP Kinase Activation

It has emerged that neutrophils can play important roles in the host response following infection with helminth parasites. Mice infected with the tapeworm, Hymenolepis diminuta, are protected from some inflammatory conditions, accompanied by reduced neutrophil tissue infiltration. Thus, the ability of a phosphate-buffered saline-soluble extract of the worm (H. diminuta extract [HdE]) was tested for (1) its ability to activate murine neutrophils (Ca2+ mobilization, reactive oxygen species (ROS) and cytokine production); and (2) affect neutrophil chemotaxis in vitro to the penta-peptide, WKYMVm, the chemokine, KC, and leukotriene B4. HdE was not cytotoxic to neutrophils, elicited a Ca2+ response and ROS, but not, cytokine (KC, interleukin-10, tumour necrosis factor-α) generation. HdE is not a chemotactic stimulus for murine neutrophils. However, a heat- and trypsin-sensitive, acid-insensitive proteoglycan (sensitive to sodium metaperiodate) in the HdE significantly reduced neutrophil chemotaxis towards WKYMVm or KC, but not LTB4. The latter suggested that the HdE interfered with p38 mitogen-activated protein kinase signalling, which is important in WKYMVm chemotaxis. Corroborating this, immunoblotting revealed reduced phosphorylated p38, and the downstream signal heat-shock protein-27, in protein extracts from HdE + WkYMVm treated cells compared to those exposed to the penta-peptide only. We speculate that HdE can be used to modify the outcome of neutrophilic disease and that purification of the bioactive proteoglycan(s) from the extract could be used as a template to design immunomodulatory drugs targeting neutrophils.