Influence of Zn2 + , Sodium Bicarbonate, and Citric Acid on the Antibacterial Activity of Ovotransferrin against E. coli O157:H7 and L. monocytogenes in Model Systems and Ham

The antibacterial activity of natural apo-ovotransferrin against E. coli O157:H7 and L. monocytogenes in model systems increased as the concentration of sodium bicarbonate increased. NaHCO3 at 100 mM markedly increased antibacterial activity of ovotransferrin against E. coli O157:H7 and L. monocytogenes. Citric acid at 0.5% enhanced antibacterial activity of apo-ovotransferrin against E. coli O157:H7, but 0.5% citric acid alone also showed a strong bactericidal activity against L. monocytogenes. Addition of NaHCO3 negated the strong antibacterial activity of ovotransferrin plus citric acid against the two pathogens. The antimicrobial activity of ovotransferrin was greatly enhanced by acidic pH conditions. Zn-bound ovotransferrin produced a bacteriostatic effect against L. monocytogenes, but Fe-bound ovotransferrin had little or no antibacterial activity against E. coli O157:H7 and L. monocytogenes. Considering these results, iron bind capacity of ovotransferrin is not the major cause of antibacterial action of ovotransferrin. Previous studies indicate that ovotransferrin directly interacts with bacterial membranes causing a variety of physiochemical changes which affect the survival of microorganisms. Ovotransferrin plus 100 mM NaHCO3 did not exhibit any antibacterial activity against two pathogens in commercial hams, whereas ovotransferrin + 0.5% citric acid suppressed L. monocytogenes in irradiated hams but not in non-irradiated hams. There are some limitations of using ovotransferrin to control pathogens in meat or meat products. To overcome these problems, further studies are needed to determine the mechanisms of antibacterial activity of ovotransferrin and to identify various factors that can improve the antibacterial activity of ovotransferrin

Effect of EDTA and Lysozyme on the Antimicrobial Activity of Ovotransferrin against Listeria monocytogenes

This study evaluated the effect of EDTA and lysozyme on the antibacterial activities of activated ovotransferrin against 5 strains of L. monocytogenes. First, a disc test was performed to screen the concentrations of EDTA or lysozyme that showed antibacterial activities in ovotransferrin (O) or ovotransferrin in 100 mM NaHCO3 (OS) solution. Turbidity and viability test were conducted using O or OS solution combined with either lysozyme (OL and OSL) or EDTA (OE and OSE). Also, OS combined with 2 mg/ml lysozyme (OSL) or/and 1 mg/ml EDTA (OSLE) were applied on commercial hams to determine if the solutions show antibacterial activities on meat products. The effect of initial cell population on the antibacterial activities of ovotransferrin combined with either EDTA or lysozyme was also determined. L. monocytogenes started to grow after 1 day of incubation in the presence of \u3e 2.0 mg/ml lysozyme. OL groups showed weak antibacterial activities against L. monocytogenes in BHI broth culture and their activities were bacteriostatic. OSL groups were bactericidal against L. monocytogenes, resulting in 1 log reduction from initial cell population. Even though OSL showed stronger antibacterial activity than OS, lysozyme had no significant effect on antibacterial activity of OS against L. monocytogenes. Also, EDTA itself at 1.0 and 2.0 mg/ml were bacteriostatic against 5 strains of L. monocytogenes. They were more susceptible to EDTA than lysozyme, and OSE1 and OSE2 had bactericidal activity against L. monocytogenes. There was a significant difference in the survivor cell populations between OS and OSE groups (p \u3c 0.05). Therefore, EDTA enhanced the antibacterial activity of OS against L. monocytogenes. However, ovotransferrin plus either lysozyme or/and EDTA did not show any antibacterial effect in commercial hams during storage at 10 o C. In addition, the initial population of L. monocytogenes cells influenced the antibacterial activity of OSL or OSE

EDTA and Lysozyme Improves Antimicrobial Activities of Ovotransferrin against Escherichia coli O157:H7

The aim of this study was to evaluate the effect of ethylenediaminetetraacetic acid (EDTA) or/and lysozyme on the antibacterial activity of ovotransferrin against E. coli O157:H7. Ovotransferrin solution (20 mg/ml) containing 100 mM-NaHCO3 (OS) was added with EDTA (2.0 or 2.5 mg/ml), lysozyme (1.0, 1.5, or 2.0 mg/ml) or both were prepared. Antibacterial activities of OS (20 mg/ml ovotransferrin + 100 mM-NaHCO3), OSE (OS+ EDTA), or OSL (OS + lysozyme) against E. coli O157:H7 in model systems were investigated by turbidity and viability tests. Also, OSE, OSL or OSEL (OS + EDTA + lysozyme) was applied on irradiated pork chops and commercial hams to determine if the solutions have antibacterial activity on meat products. The effect of initial cell population on the antibacterial activity of ovotransferrin and EDTA or lysozyme combinations was also determined. EDTA at 2 mg/ml plus OS (OSE2) induced 3 ~ 4 log reduction in viable E. coli O157:H7 cells in brain heart infusion (BHI) broth media, and 1 mg/ml lysozyme plus OS (OSL1) resulted in 0.5 ~ 1.0 log reduction during 35 oC incubation for 36 hr. However, OSE or OSEL did not show significant antibacterial effect on pork chops and hams during storage at 10 oC. The initial cell number in media did not affect the antibacterial activity of OSE or OSEL against E. coli O157:H7. This study demonstrates that combinations of ovotransferrin, NaHCO3, and EDTA (OSE) have potential to control E. coli O157:H7

Improving hospital-based opioid substitution therapy (iHOST): protocol for a mixed-methods evaluation

BACKGROUND: Opioid substitution therapy is associated with improved health and social outcomes for people who use heroin and other illicit opioids. It is typically managed in the community and is not always continued when people are admitted to hospital. This causes opioid withdrawal, discharge against medical advice, and increased costs. We are establishing a project called iHOST (improving hospital opioid substitution therapy) to address these problems. This is an applied health research project in which we will develop and evaluate an intervention that aims to improve opioid substitution therapy in three acute hospitals in England. The intervention was developed in collaboration with stakeholders including people who use opioids, hospital staff, and other professionals who work with this group. It includes five components: (1) a card that patients can use to help hospital clinicians confirm their opioid substitution therapy, (2) a helpline for patients and staff, (3) an online training module for staff, (4) a clinical guideline for managing opioid withdrawal in hospital, and (5) ‘champion’ roles at each hospital. METHODS: We will do a mixed-methods study including a quasi-experimental quantitative study and a qualitative process evaluation. The primary outcomes for the quantitative study are discharge against medical advice and emergency readmission within 28 days. We will do a difference-in-difference analysis comparing changes in these outcomes for patients at iHOST sites with changes for patients at control hospitals. The process evaluation will use in-depth interviews, focus groups, and site observations with people who use opioids and staff. We will assess acceptability of the intervention, barriers and facilitators to implementation, and contextual factors impacting outcomes. IMPACT: We anticipate that iHOST will improve care for hospital patients who use illicit opioids and/or are receiving community-based opioid substitution therapy. Depending on the results, we will promote the intervention at hospitals across the UK. Dissemination, including through publication, will inform hospital-based services for people who use drugs both in the UK and other countries

Experimental determination of photostability and fluorescence-based detection of PAHs on the Martian surface

Even in the absence of any biosphere on Mars, organic molecules, including polycyclic aromatic hydrocarbons (PAHs), are expected on its surface due to delivery by comets and meteorites of extraterrestrial organics synthesized by astrochemistry, or perhaps in situ synthesis in ancient prebiotic chemistry. Any organic compounds exposed to the unfiltered solar ultraviolet spectrum or oxidizing surface conditions would have been readily destroyed, but discoverable caches of Martian organics may remain shielded in the subsurface or within surface rocks. We have studied the stability of three representative polycyclic aromatic hydrocarbons (PAHs) in a Mars chamber, emulating the ultraviolet spectrum of unfiltered sunlight under temperature and pressure conditions of the Martian surface. Fluorescence spectroscopy is used as a sensitive indicator of remaining PAH concentration for laboratory quantification of molecular degradation rates once exposed on the Martian surface. Fluorescence-based instrumentation has also been proposed as an effective surveying method for prebiotic organics on the Martian surface. We find the representative PAHs, anthracene, pyrene, and perylene, to have persistence half-lives once exposed on the Martian surface of between 25 and 60 h of noontime summer UV irradiation, as measured by fluorescence at their peak excitation wavelength. This equates to between 4 and 9.6 sols when the diurnal cycle of UV light intensity on the Martian surface is taken into account, giving a substantial window of opportunity for detection of organic fluorescence before photodegradation. This study thus supports the use of fluorescence-based instrumentation for surveying recently exposed material (such as from cores or drill tailings) for native Martian organic molecules in rover missions

Transcriptional networks orchestrating programmed cell death during plant development

Transcriptional gene regulation is a fundamental biological principle in the development of eukaryotes. It does control not only cell proliferation, specification, and differentiation, but also cell death processes as an integral feature of an organism's developmental program. As in animals, developmentally regulated cell death in plants occurs in numerous contexts and is of vital importance for plant vegetative and reproductive development. In comparison with the information available on the molecular regulation of programmed cell death (PCD) in animals, however, our knowledge on plant PCD still remains scarce. Here, we discuss the functions of different classes of transcription factors that have been implicated in the control of developmentally regulated cell death. Though doubtlessly representing but a first layer of PCD regulation, information on PCD-regulating transcription factors and their targets represents a promising strategy to understand the complex machinery that ensures the precise and failsafe execution of PCD processes in plant development

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

EDTA and Lysozyme Improves Antimicrobial Activities of Ovotransferrin against Escherichia coli O157:H7

The aim of this study was to evaluate the effect of ethylenediaminetetraacetic acid (EDTA) or/and lysozyme on the antibacterial activity of ovotransferrin against E. coli O157:H7. Ovotransferrin solution (20 mg/ml) containing 100 mM-NaHCO3 (OS) was added with EDTA (2.0 or 2.5 mg/ml), lysozyme (1.0, 1.5, or 2.0 mg/ml) or both were prepared. Antibacterial activities of OS (20 mg/ml ovotransferrin + 100 mM-NaHCO3), OSE (OS+ EDTA), or OSL (OS + lysozyme) against E. coli O157:H7 in model systems were investigated by turbidity and viability tests. Also, OSE, OSL or OSEL (OS + EDTA + lysozyme) was applied on irradiated pork chops and commercial hams to determine if the solutions have antibacterial activity on meat products. The effect of initial cell population on the antibacterial activity of ovotransferrin and EDTA or lysozyme combinations was also determined. EDTA at 2 mg/ml plus OS (OSE2) induced 3 ~ 4 log reduction in viable E. coli O157:H7 cells in brain heart infusion (BHI) broth media, and 1 mg/ml lysozyme plus OS (OSL1) resulted in 0.5 ~ 1.0 log reduction during 35 oC incubation for 36 hr. However, OSE or OSEL did not show significant antibacterial effect on pork chops and hams during storage at 10 oC. The initial cell number in media did not affect the antibacterial activity of OSE or OSEL against E. coli O157:H7. This study demonstrates that combinations of ovotransferrin, NaHCO3, and EDTA (OSE) have potential to control E. coli O157:H7.</p

Effect of EDTA and Lysozyme on the Antimicrobial Activity of Ovotransferrin against Listeria monocytogenes

This study evaluated the effect of EDTA and lysozyme on the antibacterial activities of activated ovotransferrin against 5 strains of L. monocytogenes. First, a disc test was performed to screen the concentrations of EDTA or lysozyme that showed antibacterial activities in ovotransferrin (O) or ovotransferrin in 100 mM NaHCO3 (OS) solution. Turbidity and viability test were conducted using O or OS solution combined with either lysozyme (OL and OSL) or EDTA (OE and OSE). Also, OS combined with 2 mg/ml lysozyme (OSL) or/and 1 mg/ml EDTA (OSLE) were applied on commercial hams to determine if the solutions show antibacterial activities on meat products. The effect of initial cell population on the antibacterial activities of ovotransferrin combined with either EDTA or lysozyme was also determined. L. monocytogenes started to grow after 1 day of incubation in the presence of > 2.0 mg/ml lysozyme. OL groups showed weak antibacterial activities against L. monocytogenes in BHI broth culture and their activities were bacteriostatic. OSL groups were bactericidal against L. monocytogenes, resulting in 1 log reduction from initial cell population. Even though OSL showed stronger antibacterial activity than OS, lysozyme had no significant effect on antibacterial activity of OS against L. monocytogenes. Also, EDTA itself at 1.0 and 2.0 mg/ml were bacteriostatic against 5 strains of L. monocytogenes. They were more susceptible to EDTA than lysozyme, and OSE1 and OSE2 had bactericidal activity against L. monocytogenes. There was a significant difference in the survivor cell populations between OS and OSE groups (p o C. In addition, the initial population of L. monocytogenes cells influenced the antibacterial activity of OSL or OSE.</p

Influence of Zn2 + , Sodium Bicarbonate, and Citric Acid on the Antibacterial Activity of Ovotransferrin against E. coli O157:H7 and L. monocytogenes in Model Systems and Ham

The antibacterial activity of natural apo-ovotransferrin against E. coli O157:H7 and L. monocytogenes in model systems increased as the concentration of sodium bicarbonate increased. NaHCO3 at 100 mM markedly increased antibacterial activity of ovotransferrin against E. coli O157:H7 and L. monocytogenes. Citric acid at 0.5% enhanced antibacterial activity of apo-ovotransferrin against E. coli O157:H7, but 0.5% citric acid alone also showed a strong bactericidal activity against L. monocytogenes. Addition of NaHCO3 negated the strong antibacterial activity of ovotransferrin plus citric acid against the two pathogens. The antimicrobial activity of ovotransferrin was greatly enhanced by acidic pH conditions. Zn-bound ovotransferrin produced a bacteriostatic effect against L. monocytogenes, but Fe-bound ovotransferrin had little or no antibacterial activity against E. coli O157:H7 and L. monocytogenes. Considering these results, iron bind capacity of ovotransferrin is not the major cause of antibacterial action of ovotransferrin. Previous studies indicate that ovotransferrin directly interacts with bacterial membranes causing a variety of physiochemical changes which affect the survival of microorganisms. Ovotransferrin plus 100 mM NaHCO3 did not exhibit any antibacterial activity against two pathogens in commercial hams, whereas ovotransferrin + 0.5% citric acid suppressed L. monocytogenes in irradiated hams but not in non-irradiated hams. There are some limitations of using ovotransferrin to control pathogens in meat or meat products. To overcome these problems, further studies are needed to determine the mechanisms of antibacterial activity of ovotransferrin and to identify various factors that can improve the antibacterial activity of ovotransferrin.</p