Investigating the association between nitrate dosing and nitrite generation by the human oral microbiota in continuous culture.

The generation of nitrite by the oral microbiota is believed to contribute to healthy cardiovascular function, with oral nitrate reduction to nitrite associated with systemic blood pressure regulation. There is the potential to manipulate the composition or activities of the oral microbiota to a higher nitrate-reducing state through nitrate supplementation. The current study examined microbial community composition and enzymatic responses to nitrate supplementation in sessile oral microbiota grown in continuous culture. Nitrate reductase (NaR) activity and nitrite concentrations were not significantly different to tongue-derived inocula in model biofilms. These were generally dominated by Streptococcus spp., initially, and a single nitrate supplementation resulted in the increased relative abundance of the nitrate-reducing genera Veillonella, Neisseria, and Proteus spp. Nitrite concentrations increased concomitantly and continued to increase throughout oral microbiota development. Continuous nitrate supplementation, over a 7-day period, was similarly associated with an elevated abundance of nitrate-reducing taxa and increased nitrite concentration in the perfusate. In experiments in which the models were established in continuous low or high nitrate environments, there was an initial elevation in nitrate reductase, and nitrite concentrations reached a relatively constant concentration over time similar to the acute nitrate challenge with a similar expansion of Veillonella and Neisseria. In summary, we have investigated nitrate metabolism in continuous culture oral biofilms, showing that nitrate addition increases nitrate reductase activity and nitrite concentrations in oral microbiota with the expansion of putatively NaR-producing taxa.IMPORTANCEClinical evidence suggests that blood pressure regulation can be promoted by nitrite generated through the reduction of supplemental dietary nitrate by the oral microbiota. We have utilized oral microbiota models to investigate the mechanisms responsible, demonstrating that nitrate addition increases nitrate reductase activity and nitrite concentrations in oral microbiota with the expansion of nitrate-reducing taxa.

Variable effects of exposure to ionic silver in wound-associated bacterial pathogens.

Silver compounds are used in wound dressings to reduce bioburden. Where infection is not rapidly resolved, bacteria may be exposed to sub-therapeutic concentrations of antimicrobials over prolonged periods of time. In this study, a panel of chronic wound bacteria, Pseudomonas aeruginosa (two strains), Staphylococcus aureus, and Escherichia coli, were exposed to silver nitrate on agar. Phenotypic characterization was achieved using broth microdilution sensitivity testing, a crystal violet biofilm assay, and a wax moth pathogenesis model. Repeated exposure to ionic silver did not result in planktonic phenotypic silver resistance in any of the test panels, although S. aureus demonstrated reversible increases in minimum bactericidal concentration. An ulcer-derived P. aeruginosa exhibited marked reductions in biofilm eradication concentration as well as significantly increased biofilm formation and wax moth killing when compared to the same progenitor. These changes were reversible, trending towards baseline measurements following 10 passages on silver-free media. Changes in virulence and biofilm formation in the other test bacteria were generally limited. In summary, phenotypic adaptation following exposure to ionic silver was manifested other than through changes in planktonic susceptibility. Significant changes in pseudomonas biofilm formation and sensitivity could have implications for wound care regimes and therefore warrant further investigation.

Altered Oral Nitrate Reduction and Bacterial Profiles in Hypertensive Women Predict Blood Pressure Lowering Following Acute Dietary Nitrate Supplementation.

BACKGROUND: The efficacy of dietary nitrate supplementation to lower blood pressure (BP) in pregnant women is highly variable. We aimed to investigate whether differences in oral microbiota profiles and oral nitrate-reducing capacity may explain interindividual differences in BP lowering following nitrate supplementation. METHODS: Participants recruited for this study were both pregnant and nonpregnant women, with or without hypertension (n=55). Following an overnight fast, plasma, saliva, and tongue scraping samples were collected for measurement of nitrate/nitrite concentrations, oral NaR (nitrate reductase) activity, and microbiota profiling using 16S rRNA gene sequencing. Baseline BP was measured, followed by the administration of a single dose of dietary nitrate (400 mg nitrate in 70 mL beetroot juice). Post-nitrate intervention, plasma and salivary nitrate/nitrite concentrations and BP were determined 2.5 hours later. RESULTS: Women with hypertension had significantly lower salivary nitrite concentrations (P=0.006) and reduced abundance of the nitrate-reducing taxa Veillonella(P=0.007) compared with normotensive women. Oral NaR activity was not significantly different in pregnant versus nonpregnant women (P=0.991) but tended to be lower in hypertensive compared with normotensive women (P=0.099). Oral NaR activity was associated with both baseline diastolic BP (P=0.050) and change in diastolic BP following acute nitrate intake (P=0.01, adjusted for baseline BP). CONCLUSIONS: The abundance and activity of oral nitrate-reducing bacteria impact both baseline BP as well as the ability of dietary nitrate supplementation to lower BP. Strategies to increase oral nitrate-reducing capacity could lower BP and enhance the efficacy of dietary nitrate supplementation, in pregnancy as well as in nonpregnant adults. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT03930693.

Characterization of Brazilian spring wheat germplasm and its potential for increasing wheat genetic diversity in Canada.

In the present era of climate instability, Canadian wheat production has been frequently affected by abiotic stresses and by dynamic populations of pathogens and pests that are more virulent and aggressive over time. Genetic diversity is fundamental to guarantee sustainable and improved wheat production. In the past, the genetics of Brazilian cultivars, such as Frontana, have been studied by Canadian researchers and consequently, Brazilian germplasm has been used to breed Canadian wheat cultivars. The objective of this study was to characterize a collection of Brazilian germplasm under Canadian growing conditions, including the reaction of the Brazilian germplasm to Canadian isolates/pathogens and to predict the presence of certain genes in an effort to increase genetic diversity, improve genetic gain and resilience of Canadian wheat. Over 100 Brazilian hard red spring wheat cultivars released from 1986 to 2016 were evaluated for their agronomic performance in eastern Canada. Some cultivars showed good adaptability, with several cultivars being superior or statistically equal to the highest yielding Canadian checks. Several Brazilian cultivars had excellent resistance to leaf rust, even though only a few of these tested positive for the presence of either Lr34 or Lr16, two of the most common resistance genes in Canadian wheat. Resistance for stem rust, stripe rust and powdery mildew was variable among the Brazilian cultivars. However, many Brazilian cultivars had high levels of resistance to Canadian and African - Ug99 strains of stem rust. Many Brazilian cultivars had good Fusarium head blight (FHB) resistance, which appears to be derived from Frontana. In contrast FHB resistance in Canadian wheat is largely based on the Chinese variety, Sumai-3. The Brazilian germplasm is a valuable source of semi-dwarf (Rht) genes, and 75% of the Brazilian collection possessed Rht-B1b. Many cultivars in the Brazilian collection were found to be genetically distinct from Canadian wheat, making them a valuable resource to increase the disease resistance and genetic variability in Canada and elsewhere.

Antibacterial effects in blood irradiated with a polychromatic device mediated through reactive oxygen species: possible involvement of haem.

The antibacterial effects of a polychromatic light device designed for intravenous application were assessed in vitro. Staphylococcus aureus, Klebsiella pneumoniae, or Escherichia coli were exposed to a 60-min sequential light cycle comprising 365, 530, and 630 nm wavelengths in circulated sheep blood. Bacteria were quantified by viable counting. The potential involvement of reactive oxygen species in the antibacterial effect was assessed using the antioxidant N-acetylcysteine-amide. A modified device was then used to determine the effects of the individual wavelengths. Exposure of blood to the standard wavelength sequence caused small (c. 0.5 Log 10 CFU) but statistically significant reductions in viable counts for all three bacteria, which were prevented by the addition of N-acetylcysteine-amide. Bacterial inactivation did not occur in blood-free medium, but supplementation with haem restored the moderate bactericidal effect. In single-wavelength experiments, bacterial inactivation occurred only with red (630 nm) light. Concentrations of reactive oxygen species were significantly higher under light stimulation than in unstimulated controls. In summary, exposure of bacteria within blood to a cycle of visible light wavelengths resulted in small but statistically significant bacterial inactivation apparently mediated by a 630 nm wavelength only, via reactive oxygen species possibly generated by excitation of haem groups.

Visible label-free detection of bacterial DNA using flocculation of sterically stabilised cationic latexes.

The current gold standard diagnostic for bacterial infections is the use of culture, which can be time consuming and can take up to five days for results to be reported. There is therefore an unmet clinical need for a rapid and label free alternative. This paper demonstrates a method of detecting the presence of amplified DNA from bacterial samples using a sterically-stabilised, cationic polymer latex and widely available equipment, providing an accessible alternative DNA detection technique. If DNA is present in a sample, successful amplification by polymerase chain-reaction (PCR) results in the amplified DNA inducing flocculation of the polymer latex followed by rapid sedimentation. This results in a visible and obvious change from a milky-white dispersion to a precipitated latex with a colourless and transparent supernatant, thus giving a clear visual indication of the presence or absence of amplified DNA. Specifically, the response of four polymer latexes with different morphologies to the addition of amplified bacterial DNA was investigated. Cationic latexes flocculated rapidly whereas non-ionic and anionic latexes did not, as judged by eye, disc centrifuge photosedimentometry (DCP), and UV-visible spectrophotometry. The stability of several cationic latexes with different morphologies in typical PCR reagents was investigated. It was found that unwanted flocculation occurred for a latex with a non-ionic core and a cationic corona (poly[2-vinyl pyridine-b-benzyl methacrylate], prepared by polymerisation-induced self-assembly) whereas a ∼700 nm PEGMA-stabilised P2VP latex (non-ionic stabiliser, cationic core), prepared by emulsion polymerisation remained stable. The sensitivity and rate of sedimentation of the PEGMA-stabilised P2VP latex was demonstrated by varying the sequence length and concentration of amplified DNA from Pseudomonas aeruginosa using universal bacterial primers. DNA concentrations as low as 0.78 ng µl-1 could readily be detected within 30 minutes from the addition of amplified DNA to the latex. Furthermore, the specificity of this method was demonstrated by showing a negative result occurs (no flocculation of the latex) when PCR product from a fungal (Candida albicans) sample using bacterial primers was added to the latex.

Distinct microbiome profiles in convergent wisdom tooth impactions.

AIMS: Long-term retention of impacted third molars (wisdom teeth) is associated with plaque stagnation and the development of caries on the adjacent surface of the neighboring second molar. While caries and tooth loss are common outcomes of impaction, there is currently insufficient evidence to support the pre-emptive removal of asymptomatic wisdom teeth. Emerging evidence suggests that convergently growing impactions are associated with caries. We have therefore investigated the composition of dental plaque on the distal surface of the mandibular second molar at various impaction angles. METHODS AND RESULTS: We have compared the microbiome of these surfaces at four impaction angulations using short-read sequencing of the bacterial 16S rRNA gene: two convergent (horizontal and mesial) and two divergent (distal and vertical) angulations, and in cases where the wisdom tooth is missing. Horizontal angulations exhibited lower microbial diversity than mesial impactions. Amplicon Sequence Variants (ASVs) associated with Veillonella were significantly more abundant at impactions with angulations toward the midline. Using machine learning, a random forest classifier trained to distinguish microbiome profiles was used to predict the native angulations for a subset of samples, with samples from the two convergent impactions estimated with the greatest accuracy. CONCLUSIONS: Differences in microbial diversity were apparent between caries-associated convergent (horizontal and mesial) impacted wisdom teeth, as well as greater abundances of Veillonella ASVs at horizontal impactions.

Honey: An Advanced Antimicrobial and Wound Healing Biomaterial for Tissue Engineering Applications.

Honey was used in traditional medicine to treat wounds until the advent of modern medicine. The rising global antibiotic resistance has forced the development of novel therapies as alternatives to combat infections. Consequently, honey is experiencing a resurgence in evaluation for antimicrobial and wound healing applications. A range of both Gram-positive and Gram-negative bacteria, including antibiotic-resistant strains and biofilms, are inhibited by honey. Furthermore, susceptibility to antibiotics can be restored when used synergistically with honey. Honey's antimicrobial activity also includes antifungal and antiviral properties, and in most varieties of honey, its activity is attributed to the enzymatic generation of hydrogen peroxide, a reactive oxygen species. Non-peroxide factors include low water activity, acidity, phenolic content, defensin-1, and methylglyoxal (Leptospermum honeys). Honey has also been widely explored as a tissue-regenerative agent. It can contribute to all stages of wound healing, and thus has been used in direct application and in dressings. The difficulty of the sustained delivery of honey's active ingredients to the wound site has driven the development of tissue engineering approaches (e.g., electrospinning and hydrogels). This review presents the most in-depth and up-to-date comprehensive overview of honey's antimicrobial and wound healing properties, commercial and medical uses, and its growing experimental use in tissue-engineered scaffolds.

Transitory Shifts in Skin Microbiota Composition and Reductions in Bacterial Load and Psoriasin following Ethanol Perturbation.

Personal care and hygiene regimens may substantially alter the composition of the skin microbiota through direct and indirect mechanisms. An understanding of the timescales of commensal skin microbiota reestablishment following perturbation is required to inform consumer safety risk assessment, and support product development. In the current investigation, the microbiota of the volar and dorsal forearm of 10 volunteers was sampled immediately before and after wiping with 70% ethanol and at up to 24 h afterwards. Quantitative PCR and amplicon sequencing were used to measure microbial load and composition, and concentrations of the antimicrobial peptide psoriasin were measured using an enzyme-linked immunosorbent assay (ELISA). Ethanol wiping significantly reduced the total bacterial abundance at 2 h post-wipe. Recovery was observed after 6 h for total bacterial populations and for Staphylococcus epidermidis depending on the site tested. Microbiome diversity recovered by 6 h after wiping. Psoriasin concentrations were highly variable between volunteers, ranging from 42 to 1,569 ng/mL, and dorsal concentrations were significantly higher than volar concentrations (P < 0.05). For most of the volunteers, the application of ethanol decreased psoriasin concentrations, particularly for the dorsal samples, but the overall effect was not significant. This work extends observations of skin microbiome stability and demonstrates resilience in a key antimicrobial peptide. IMPORTANCE An understanding of the timescales of commensal skin microbiota reestablishment following perturbation is required to inform consumer safety risk assessment and support product development. Following ethanol exposure, total bacterial populations and microbiome diversity recovered after 6 h. For most of the volunteers, the application of ethanol decreased psoriasin concentrations, but the overall effect was not significant. This work extends observations of skin microbiome stability and demonstrates resilience in a key antimicrobial peptide.

Assessing the risk of resistance to cationic biocides incorporating realism-based and biophysical approaches.

The control of microorganisms is a key objective in disease prevention and in medical, industrial, domestic, and food-production environments. Whilst the effectiveness of biocides in these contexts is well-evidenced, debate continues about the resistance risks associated with their use. This has driven an increased regulatory burden, which in turn could result in a reduction of both the deployment of current biocides and the development of new compounds and formulas. Efforts to balance risk and benefit are therefore of critical importance and should be underpinned by realistic methods and a multi-disciplinary approach, and through objective and critical analyses of the literature. The current literature on this topic can be difficult to navigate. Much of the evidence for potential issues of resistance generation by biocides is based on either correlation analysis of isolated bacteria, where reports of treatment failure are generally uncommon, or laboratory studies that do not necessarily represent real biocide applications. This is complicated by inconsistencies in the definition of the term resistance. Similar uncertainties also apply to cross-resistance between biocides and antibiotics. Risk assessment studies that can better inform practice are required. The resulting knowledge can be utilised by multiple stakeholders including those tasked with new product development, regulatory authorities, clinical practitioners, and the public. This review considers current evidence for resistance and cross-resistance and outlines efforts to increase realism in risk assessment. This is done in the background of the discussion of the mode of application of biocides and the demonstrable benefits as well as the potential risks.

Preliminary Characterization of a Polycaprolactone-SurgihoneyRO Electrospun Mesh for Skin Tissue Engineering.

Skin is a hierarchical and multi-cellular organ exposed to the external environment with a key protective and regulatory role. Wounds caused by disease and trauma can lead to a loss of function, which can be debilitating and even cause death. Accelerating the natural skin healing process and minimizing the risk of infection is a clinical challenge. Electrospinning is a key technology in the development of wound dressings and skin substitutes as it enables extracellular matrix-mimicking fibrous structures and delivery of bioactive materials. Honey is a promising biomaterial for use in skin tissue engineering applications and has antimicrobial properties and potential tissue regenerative properties. This preliminary study investigates a solution electrospun composite nanofibrous mesh based on polycaprolactone and a medical grade honey, SurgihoneyRO. The processing conditions were optimized and assessed by scanning electron microscopy to fabricate meshes with uniform fiber diameters and minimal presence of beads. The chemistry of the composite meshes was examined using Fourier transform infrared spectroscopy and X-ray photon spectroscopy showing incorporation of honey into the polymer matrix. Meshes incorporating honey had lower mechanical properties due to lower polymer content but were more hydrophilic, resulting in an increase in swelling and an accelerated degradation profile. The biocompatibility of the meshes was assessed using human dermal fibroblasts and adipose-derived stem cells, which showed comparable or higher cell metabolic activity and viability for SurgihoneyRO-containing meshes compared to polycaprolactone only meshes. The meshes showed no antibacterial properties in a disk diffusion test due to a lack of hydrogen peroxide production and release. The developed polycaprolactone-honey nanofibrous meshes have potential for use in skin applications.

Exposure to a Manuka Honey Wound Gel Is Associated With Changes in Bacterial Virulence and Antimicrobial Susceptibility.

The use of manuka honey for the topical treatment of wounds has increased worldwide owing to its broad spectrum of activity towards bacteria in both planktonic and biofilm growth modes. Despite this, the potential consequences of bacterial exposure to manuka honey, as may occur during the treatment of chronic wounds, are not fully understood. Here, we describe changes in antimicrobial susceptibility and virulence in a panel of bacteria, including wound isolates, following repeated exposure (ten passages) to sub-inhibitory concentrations of a manuka honey based wound gel. Changes in antibiotic sensitivity above 4-fold were predominantly related to increased vancomycin sensitivity in the staphylococci. Interestingly, Staphylococcus epidermidis displayed phenotypic resistance to erythromycin following passaging, with susceptibility profiles returning to baseline in the absence of further honey exposure. Changes in susceptibility to the tested wound gel were moderate (≤ 1-fold) when compared to the respective parent strain. In sessile communities, increased biofilm eradication concentrations over 4-fold occurred in a wound isolate of Pseudomonas aeruginosa (WIBG 2.2) as evidenced by a 7-fold reduction in gentamicin sensitivity following passaging. With regards to pathogenesis, 4/8 bacteria exhibited enhanced virulence following honey wound gel exposure. In the pseudomonads and S. epidermidis, this occurred in conjunction with increased haemolysis and biofilm formation, whilst P. aeruginosa also exhibited increased pyocyanin production. Where virulence attenuation was noted in a passaged wound isolate of S. aureus (WIBG 1.6), this was concomitant to delayed coagulation and reduced haemolytic potential. Overall, passaging in the presence of a manuka honey wound gel led to changes in antimicrobial sensitivity and virulence that varied between test bacteria.

Does the Oral Microbiome Play a Role in Hypertensive Pregnancies?

Chronic hypertension during gestation is associated with an increased risk of adverse pregnancy outcomes including pre-eclampsia, fetal growth restriction and preterm birth. Research into new chemotherapeutic regimes for the treatment of hypertension in pregnancy is limited due to concerns about fetal toxicity and teratogenicity, and new therapeutic avenues are being sought in alternative physiological pathways. Historically, generation of the vasodilator nitric oxide was believed to be solely from L-arginine by means of nitric oxide synthase enzymes. Recently, a novel pathway for the reduction of dietary inorganic nitrate to nitrite by the bacteria in the oral cavity and subsequently to vasodilatory nitric oxide within the body has been uncovered. Dietary nitrate is abundant in green leafy vegetables, including beetroot and spinach, and reduction of exogenous nitrate to nitrite by oral bacteria can increase nitric oxide in the vasculature, lessening hypertension. Supplements rich in nitrate may be an attractive choice for treatment due to fewer side effects than drugs that are currently used to treat hypertensive pregnancy disorders. Additionally, manipulation of the composition of the oral microbiota using pro- and prebiotics in tandem with additional dietary interventions to promote cardiovascular health during gestation may offer a safe and effective means of treating hypertensive pregnancy disorders including gestational hypertension and pre-eclampsia. The use of dietary inorganic nitrate as a supplement during pregnancy requires further exploration and large scale studies before it may be considered as part of a treatment regime. The aim of this article is to review the current evidence that oral microbiota plays a role in hypertensive pregnancies and whether it could be manipulated to improve patient outcomes.

Does the Microbiome Affect the Outcome of Renal Transplantation?

The role of the human microbiome in health and disease is becoming increasingly apparent. Emerging evidence suggests that the microbiome is affected by solid organ transplantation. Kidney transplantation is the gold standard treatment for End-Stage Renal Disease (ESRD), the advanced stage of Chronic Kidney Disease (CKD). The question of how ESRD and transplantation affect the microbiome and vice versa includes how the microbiome is affected by increased concentrations of toxins such as urea and creatinine (which are elevated in ESRD), whether restoration of renal function following transplantation alters the composition of the microbiome, and the impact of lifelong administration of immunosuppressive drugs on the microbiome. Changes in microbiome composition and activity have been reported in ESRD and in therapeutic immunosuppression, but the effect on the outcome of transplantation is not well-understood. Here, we consider the current evidence that changes in kidney function and immunosuppression following transplantation influence the oral, gut, and urinary microbiomes in kidney transplant patients. The potential for changes in these microbiomes to lead to disease, systemic inflammation, or rejection of the organ itself is discussed, along with the possibility that restoration of kidney function might re-establish orthobiosis.

Loss of Function in Escherichia coli Exposed to Environmentally Relevant Concentrations of Benzalkonium Chloride.

Assessing the risk of resistance associated with biocide exposure commonly involves exposing microorganisms to biocides at concentrations close to the MIC. With the aim of representing exposure to environmental biocide residues, Escherichia coli MG1655 was grown for 20 passages in the presence or absence of benzalkonium chloride (BAC) at 100 ng/liter and 1,000 ng/liter (0.0002% and 0.002% of the MIC, respectively). BAC susceptibility, planktonic growth rates, motility, and biofilm formation were assessed, and differentially expressed genes were determined via transcriptome sequencing. Planktonic growth rate and biofilm formation were significantly reduced (P < 0.001) following BAC adaptation, while BAC minimum bactericidal concentration increased 2-fold. Transcriptomic analysis identified 289 upregulated and 391 downregulated genes after long-term BAC adaptation compared with the respective control organism passaged in BAC-free medium. When the BAC-adapted bacterium was grown in BAC-free medium, 1,052 genes were upregulated and 753 were downregulated. Repeated passage solely in biocide-free medium resulted in 460 upregulated and 476 downregulated genes compared with unexposed bacteria. Long-term exposure to environmentally relevant BAC concentrations increased the expression of genes associated with efflux and reduced the expression of genes associated with outer-membrane porins, motility, and chemotaxis. This was manifested phenotypically through the loss of function (motility). Repeated passage in a BAC-free environment resulted in the upregulation of multiple respiration-associated genes, which was reflected by increased growth rate. In summary, repeated exposure of E. coli to BAC residues resulted in significant alterations in global gene expression that were associated with minor decreases in biocide susceptibility, reductions in growth rate and biofilm formation, and loss of motility.IMPORTANCE Exposure to very low concentrations of biocides in the environment is a poorly understood risk factor for antimicrobial resistance. Repeated exposure to trace levels of the biocide benzalkonium chloride (BAC) resulted in loss of function (motility) and a general reduction in bacterial fitness but relatively minor decreases in susceptibility. These changes were accompanied by widespread changes in the Escherichia coli transcriptome. These results demonstrate the importance of including phenotypic characterization in studies designed to assess the risks of biocide exposure.

Allelic variation of vernalization and photoperiod response genes in a diverse set of North American high latitude winter wheat genotypes.

The major physiological determinants of wheat (Triticum aestivum L.) phenology in a given area are a response to vernalization temperature and day length, which are at least in part, regulated by the allelic variation at the vernalization (VRN) and photoperiod (PPD) loci, respectively. Characterization of the existing genetic variation for plant phenology in winter wheat can assist breeding programs improve adaptation to local environments and to optimize wheat phenology for the changing climate. The objectives of this research were to characterize the allelic variation at the major VRN and PPD loci in a diverse panel of high latitude winter wheat genotypes (n = 203) and to associate the allelic variation with phenologic, agronomic and adaptation traits. The panel was genotyped using allele-specific markers at vernalization (VRN-A1, VRN-B1, VRN-D1 and VRN-B3) and photoperiod (PPD-A1, PPD-B1, and PPD-D1) loci and phenotyped for agronomically-important traits. Though photoperiod sensitivity was more prevalent, most of the variation in the phenology of the winter wheat panel was explained by allelic variation at PPD-D1, PPD-A1, and the interaction between these loci. While a typical high latitude winter wheat genotype is one that carries winter alleles at all major VRN loci and photoperiod sensitive alleles at the major PPD loci, in lower latitudes where winters are milder, the presence of one or two photoperiod insensitive alleles seems to contribute to higher yield and wider adaptation.

Diabetic foot infection: A critical complication.

The number of people in the world with diabetes has nearly quadrupled in the past 40 years. Current data show that 25% of these diabetics will develop a foot ulcer in their lifetime and that the cost of care for a diabetic foot ulcer (DFU) is over twice that of any other chronic ulcer aetiology. Microbial biofilm has been linked to both wound chronicity and infection. Close to 1 in 2 diabetics with a DFU are predicted to go on to develop a diabetic foot infection (DFI). The majority of these DFIs have been found to evolve even before the diabetic individual has received an initial referral for expert DFU management. Of these infected DFUs, less than half have been shown to heal over the next year; many of these individuals will require costly hospitalisation, and current data show that far too many DFIs will require extremity amputation to achieve infection resolution. The development of an infection in a DFU is critical at least in part because paradigms of infection prevention and management are evolving. The effectiveness of our current practice standards is being challenged by a growing body of research related to the prevalence and recalcitrance of the microbes in biofilm to topical and systemic antimicrobials. This article will review the magnitude of current challenges related to DFI prevention and management along with what is currently considered to be standard of care. These ideas will be compared and contrasted with what is known about the biofilm phenotype; then, considerations to support progress towards the development of more cost-effective protocols of care are highlighted.

Author Correction: Grain Yield, Starch Content and Activities of Key Enzymes of Waxy and Non-waxy Wheat (Triticum aestivum L.).

A correction to this article has been published and is linked from the HTML version of this paper. The error has not been fixed in the paper.

Grain Yield, Starch Content and Activities of Key Enzymes of Waxy and Non-waxy Wheat (Triticum aestivum L.).

Waxy wheat has unique end-use properties; however, its production is limited due mainly to its low grain yield compared with non-waxy wheat. In order to increase its grain yield, it is critical to understand the eco-physiological differences in grain filling between the waxy and non-waxy wheat. In this study, two waxy wheat and two non-waxy wheat cultivars were used to investigate the differences in starch-associated enzymes processes, sucrose and starch dynamics, yield components, and the final grain yield. The results indicated that the mean total grain starch and amylose content, the average 1000-kernel weight and grain yield of the waxy wheat were lower than those of the non-waxy wheat at maturity. The amylose content was significantly and positively correlated with the activity of GBSS (r = 0.80, p < 0.01). Significant positive correlation also exists among activities of AGPase, SSS, GBSS, and SBE, except for GBSS-SBE. In summary, our study has revealed that the reduced conversion of sucrose to starch in the late grain filling stage is the main cause for the low kernel weight and total starch accumulation of the waxy wheat. The reduced conversion also appears to be a factor contributing to the lower grain yield of the waxy wheat.

Fatty Acid Supplementation Reverses the Small Colony Variant Phenotype in Triclosan-Adapted Staphylococcus aureus: Genetic, Proteomic and Phenotypic Analyses.

Staphylococcus aureus can develop a small colony variant (SCV) phenotype in response to sub-lethal exposure to the biocide triclosan. In the current study, whole genome sequencing was performed and changes in virulence were investigated in five Staphylococcus aureus strains following repeated exposure to triclosan. Following exposure, 4/5 formed SCV and exhibited point mutations in the triclosan target gene fabI with 2/4 SCVs showing mutations in both fabI and fabD. The SCV phenotype was in all cases immediately reversed by nutritional supplementation with fatty acids or by repeated growth in the absence of triclosan, although fabI mutations persisted in 3/4 reverted SCVs. Virulence, determined using keratinocyte invasion and Galleria mellonella pathogenicity assays was significantly (p < 0.05) attenuated in 3/4 SCVs and in the non-SCV triclosan-adapted bacterium. Proteomic analysis revealed elevated FabI in 2/3 SCV and down-regulation in a protein associated with virulence in 1/3 SCV. In summary, attenuated keratinocyte invasion and larval virulence in triclosan-induced SCVs was associated with decreases in growth rate and virulence factor expression. Mutation occurred in fabI, which encodes the main triclosan target in all SCVs and the phenotype was reversed by fatty acid supplementation, demonstrating an association between fatty acid metabolism and triclosan-induced SCV.