Apical Transport of Influenza A Virus Ribonucleoprotein Requires Rab11-positive Recycling Endosome

Influenza A virus RNA genome exists as eight-segmented ribonucleoprotein complexes containing viral RNA polymerase and nucleoprotein (vRNPs). Packaging of vRNPs and virus budding take place at the apical plasma membrane (APM). However, little is known about the molecular mechanisms of apical transport of newly synthesized vRNP. Transfection of fluorescent-labeled antibody and subsequent live cell imaging revealed that punctate vRNP signals moved along microtubules rapidly but intermittently in both directions, suggestive of vesicle trafficking. Using a series of Rab family protein, we demonstrated that progeny vRNP localized to recycling endosome (RE) in an active/GTP-bound Rab11-dependent manner. The vRNP interacted with Rab11 through viral RNA polymerase. The localization of vRNP to RE and subsequent accumulation to the APM were impaired by overexpression of Rab binding domains (RBD) of Rab11 family interacting proteins (Rab11-FIPs). Similarly, no APM accumulation was observed by overexpression of class II Rab11-FIP mutants lacking RBD. These results suggest that the progeny vRNP makes use of Rab11-dependent RE machinery for APM trafficking

Evaluation of appendicitis risk prediction models in adults with suspected appendicitis

Background Appendicitis is the most common general surgical emergency worldwide, but its diagnosis remains challenging. The aim of this study was to determine whether existing risk prediction models can reliably identify patients presenting to hospital in the UK with acute right iliac fossa (RIF) pain who are at low risk of appendicitis. Methods A systematic search was completed to identify all existing appendicitis risk prediction models. Models were validated using UK data from an international prospective cohort study that captured consecutive patients aged 16–45 years presenting to hospital with acute RIF in March to June 2017. The main outcome was best achievable model specificity (proportion of patients who did not have appendicitis correctly classified as low risk) whilst maintaining a failure rate below 5 per cent (proportion of patients identified as low risk who actually had appendicitis). Results Some 5345 patients across 154 UK hospitals were identified, of which two‐thirds (3613 of 5345, 67·6 per cent) were women. Women were more than twice as likely to undergo surgery with removal of a histologically normal appendix (272 of 964, 28·2 per cent) than men (120 of 993, 12·1 per cent) (relative risk 2·33, 95 per cent c.i. 1·92 to 2·84; P < 0·001). Of 15 validated risk prediction models, the Adult Appendicitis Score performed best (cut‐off score 8 or less, specificity 63·1 per cent, failure rate 3·7 per cent). The Appendicitis Inflammatory Response Score performed best for men (cut‐off score 2 or less, specificity 24·7 per cent, failure rate 2·4 per cent). Conclusion Women in the UK had a disproportionate risk of admission without surgical intervention and had high rates of normal appendicectomy. Risk prediction models to support shared decision‐making by identifying adults in the UK at low risk of appendicitis were identified

Kinetic modelling and optimisation of antimicrobial compound production by candida pyralidae KU736785 for control of candida guilliermondii

Biological antimicrobial compounds from yeast can be used to address the critical need for safer preservatives in food, fruit and beverages. The inhibition of Candida guilliermondii, a common fermented beverage spoilage organism, was achieved using antimicrobial compounds produced by Candida pyralidae KU736785. The antimicrobial production system was modelled and optimised using response surface methodology, with 22.5 C and pH of 5.0 being the optimum conditions. A new concept for quantifying spoilage organism inhibition was developed. The inhibition activity of the antimicrobial compounds was observed to be at a maximum after 17–23 h of fermentation, with C. pyralidae concentration being between 0.40 and 1.25 109 CFU ml 1, while its maximum specific growth rate was 0.31–0.54 h 1. The maximum inhibitory activity was between 0.19 and 1.08 l contaminated solidified media per millilitre of antimicrobial compound used. Furthermore, the antimicrobial compound formation rate was 0.037–0.086 l VZI ml 1 ACU h 1, respectively. The response surface methodology analysis showed that the model developed sufficiently described theantimicrobial compound formation rate 1.08 l VZI ml 1 ACU, as 1.17 l VZI ml 1 ACU, predicted under the optimum production conditions

Product and Microbial Population Kinetics During Balsamic-Styled Vinegar Production

Balsamic-styled vinegar is a nutraceutical product obtained from a two-stage fermentation process of grape must. However, little is known about how fermentation conditions affect growth kinetics, bio-product development, population dynamics and the final product quality. As a result, the current study investigated the effect of fermentation temperature and inoculation strategy on the fermentation dynamics of Balsamic-styled vinegar production. A microbial consortium of non-Saccharomyces yeasts (n = 13) and acetic acid bacteria (n = 5) was tested at various fermentation temperatures (22 °C, 28 °C and a fluctuating temperature regimen). Different inoculation strategies (co-inoculation and sequential inoculation) were investigated, and population dynamics of the product selected due to a rapid fermentation period were confirmed using a 16S and 18S gene sequencing. A higher fermentation temperature (28 °C) and co-inoculation strategy resulted in a shorter fermentation cycle, whilst the desired acetic acid concentration of 60 g/L was achieved within 38 days. 16S and 18S gene sequencing showed that 50.84% of Acetobacter species were abundant at the end of the fermentation cycle, while 40.18% bacteria were unculturable. The study provides a better understanding of how fermentation temperature and inoculation strategy affect the fermentation period, population dynamics and the growth kinetics of the microbial consortium during the production of Balsamic-styled vinegar

Cell immobilization by Gel Entrapment in Ca-alginate Beads for Balsamic-styled Vinegar Production

Conference ProceedingThe production of a high concentration of acetic acid during vinegar fermentation is a desirable occurrence for Balsamic vinegar. However, acetic acid, high osmotic pressure and low water activity resulting from the cooked grape must, can negatively affect microbial growth during fermentation. To counteract these effects, cell immobilization can improve microbial activity by protecting the cells against harsh environmental conditions. The immobilization of the microbial consortia (non-Saccharomyces yeast and acetic acid bacteria) was carried out using the calcium alginate gel beads entrapment technique. A comparative analysis of the freely suspended and gel entrapped cells was done to further evaluate the effects of surface area or bead size on acetification rates under agitated and non-agitated fermentations. Gel entrapped cell fermentations showed higher acetification rates compared to freely suspended cell fermentations. Static fermentations achieved the anticipated acetic acid production levels (60 g.L -1 ). Under these conditions, smaller beads resulted in higher acetification rates. Surface area of the beads had a significant impact on the acetification rates. Agitation promoted cell shear stress and insufficient acetification during fermentations. Gel entrapped cells using small beads under non-agitated fermentation conditions were effective for balsamic-styled vinegar production.The Agricultural Research Council (ARC), colleagues, ARC work integrated learning students are acknowledged for the infrastructural resources, financial support and technical assistance

Fungistatic and fungicidal properties of Candida pyralidae Y1117, Pichia kluyveri Y1125 and Pichia kluyveri Y1164 on the biocontrol of Botrytis cinerea

Conference ProceedingThe agro-processing industry is currently facing losses due to microbial spoilage of agricultural produce and associated value-added products such as beverages. To address this, synthetic chemicals that have potential human health and environmental effects have been widely used to control microbial spoilage. As a result, a bioprospecting approach that uses biological systems e.g. yeast as biocontrol agents is increasingly being considered in the food industry. The aim of the current study was to investigate the effect of varying inoculum dose (ID) of Candida pyralidae strain Y1117, Pichia kluyveri Y1125 and Pichia kluyveri Y1164 for the biocontrol of Botrytis cinerea. The headspace of the growth medium was contaminated with a fungal plug subsequent to biotreatment with different initial inoculum dose of the respective biocontrol agents. The results obtained showed that the fungistatic and fungicidal effects on the fungal pathogen was dose dependent. The fungistatic characteristics against Botrytis cinerea were displayed after 7 days when 102 -105 cells mL-1 of Candida pyralidae Y1117, Pichia kluyveri Y1125 and Pichia kluyveri Y1164 were independently used in-vitro and in-vivo. However, 106 -108 cells mL-1 inoculum doses displayed fungicidal characteristics. Additionally, the fungicidal property of yeasts studied was also confirmed on table grape (in vivo studies) using closed jars.The Agricultural Research Council (ARC), the National Research Foundation (NRF) of South Africa, colleagues, students and Mr Edwin Hlangwani are acknowledged for the infrastructural resources, financial support and technical assistance