An Eye to a Kill: Using Predatory Bacteria to Control Gram-Negative Pathogens Associated with Ocular Infections

Ocular infections are a leading cause of vision loss. It has been previously suggested that predatory prokaryotes might be used as live antibiotics to control infections. In this study, Pseudomonas aeruginosa and Serratia marcescens ocular isolates were exposed to the predatory bacteria Micavibrio aeruginosavorus and Bdellovibrio bacteriovorus. All tested S. marcescens isolates were susceptible to predation by B. bacteriovorus strains 109J and HD100. Seven of the 10 P. aeruginosa isolates were susceptible to predation by B. bacteriovorus 109J with 80% being attacked by M. aeruginosavorus. All of the 19 tested isolates were found to be sensitive to at least one predator. To further investigate the effect of the predators on eukaryotic cells, human corneal-limbal epithelial (HCLE) cells were exposed to high concentrations of the predators. Cytotoxicity assays demonstrated that predatory bacteria do not damage ocular surface cells in vitro whereas the P. aeruginosa used as a positive control was highly toxic. Furthermore, no increase in the production of the proinflammatory cytokines IL-8 and TNF-alpha was measured in HCLE cells after exposure to the predators. Finally, injection of high concentration of predatory bacteria into the hemocoel of Galleria mellonella, an established model system used to study microbial pathogenesis, did not result in any measurable negative effect to the host. Our results suggest that predatory bacteria could be considered in the near future as a safe topical bio-control agent to treat ocular infections. © 2013 Shanks et al

Prevalence and Clinical Profile of Severe Acute Respiratory Syndrome Coronavirus 2 Infection among Farmworkers, California, USA, June-November 2020.

During the ongoing coronavirus disease (COVID-19) pandemic, farmworkers in the United States are considered essential personnel and continue in-person work. We conducted prospective surveillance for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and antibody prevalence among farmworkers in Salinas Valley, California, during June 15-November 30, 2020. We observed 22.1% (1,514/6,864) positivity for SARS-CoV-2 infection among farmworkers compared with 17.2% (1,255/7,305) among other adults from the same communities (risk ratio 1.29, 95% CI 1.20-1.37). In a nested study enrolling 1,115 farmworkers, prevalence of current infection was 27.7% among farmworkers reporting >1 COVID-19 symptom and 7.2% among farmworkers without symptoms (adjusted odds ratio 4.16, 95% CI 2.85-6.06). Prevalence of SARS-CoV-2 antibodies increased from 10.5% (95% CI 6.0%-18.4%) during July 16-August 31 to 21.2% (95% CI 16.6%-27.4%) during November 1-30. High SARS-CoV-2 infection prevalence among farmworkers underscores the need for vaccination and other preventive interventions

Pseudomonas aeruginosa mutants defective in glucose uptake have pleiotropic phenotype and altered virulence in non-mammal infection models

Pseudomonas spp. are endowed with a complex pathway for glucose uptake that relies on multiple transporters. In this work we report the construction and characterization of Pseudomonas aeruginosa single and multiple mutants with unmarked deletions of genes encoding outer membrane (OM) and inner membrane (IM) proteins involved in glucose uptake. We found that a triple \u394gltKGF \u394gntP \u394kguT mutant lacking all known IM transporters (named GUN for Glucose Uptake Null) is unable to grow on glucose as unique carbon source. More than 500 genes controlling both metabolic functions and virulence traits show differential expression in GUN relative to the parental strain. Consistent with transcriptomic data, the GUN mutant displays a pleiotropic phenotype. Notably, the genome-wide transcriptional profile and most phenotypic traits differ between the GUN mutant and the wild type strain irrespective of the presence of glucose, suggesting that the investigated genes may have additional roles besides glucose transport. Finally, mutants carrying single or multiple deletions in the glucose uptake genes showed attenuated virulence relative to the wild type strain in Galleria mellonella, but not in Caenorhabditis elegans infection model, supporting the notion that metabolic functions may deeply impact P. aeruginosa adaptation to specific environments found inside the host

The influence of humidity on selected mechanical properties of wheat grain

W pracy przedstawiono wyniki badań dotyczące określenia wytrzymałości mechanicznej pojedynczych ziaren pszenicy o różnej wilgotności. Stwierdzono, że wraz ze wzrostem wilgotności ziarna zmniejsza się wartość siły ściskającej oraz zwiększa się energia ściskania. Nie odnotowano jednoznacznych zależności między wilgotnością ziarna a siłą i energią cięcia.The paper presents test results regarding determination of mechanical strength of single wheat grains with different humidity. It was ascertained that on the increase of grain humidity the value of compression force got reduced and compression energy got increased. No univocal dependencies between grain moisture and cutting force and cutting energy were recorded

Właściwości fizyczne nasion wybranych roślin oleistych

The paper examines the selected physical properties of seeds of 8 plants used in agri-food processing industry. These are: winter rapeseed (Brassica napus L.) Adriana cultivar, sesame (Sesamumindicum L.), common flax (Linum usitatissimum L.) Luna cultivar, husked sunflower (Helianthus L.) (country of origin – Bulgaria), hemp (Cannabis sativa L.) Benikocultivar, blue poppy (Papaver somniferum L.) Major cultivar, garden cress (Lepidium sativum L.), black caraway (Nigella Sativa L.). In the research material we determined the following: mass of thousand seeds (MTS), piling angle and angle of repose, tap and bulk density and compressive resistance of single seeds. Some seeds from the selected plant species differed with shape and size. Thus, the results determining the physical properties were varied.W pracy zbadano wybrane właściwości fizyczne nasion 8 roślin wykorzystywanych w przetwórstwie rolno-spożywczym, takich jak: rzepak ozimy (Brassica napus L.) odmiany Adriana, sezam indyjski (Sesamum indicum L.), len zwyczajny (Linum usitatissimum L.) odmiany Luna, słonecznik łuskany (Helianthus L.) (kraj pochodzenia – Bułgaria), konopie siewne (Cannabis sativa L.) odmiany Beniko, mak niebieski (Papaver somniferum L.) odmiany Major, rzeżucha ogrodowa (Lepidium sativum L.), czarnuszka siewna (Nigella Sativa L.). W materiale badawczym oznaczono: masę 1000 nasion (MTS), kąt zsypu i usypu nasion, gęstość utrzęsioną i usypową nasion oraz wytrzymałość pojedynczych nasion na ściskanie. Niektóre nasiona spośród wybranych gatunków roślin różniły się między sobą zarówno kształtem jak i wielkością, stąd też wyniki oznaczeń właściwości fizycznych były zróżnicowane

Operational testing of a laboratory paddle mixer

W pracy przedstawiono wyniki badań procesu mieszania mieszaniny dwuskładnikowej w laboratoryjnej mieszarce łopatkowej. Badano wpływ parametrów eksploatacyjnych tj. prędkość obrotowa, czas mieszania oraz ilość pierścieni w mieszarce. Wykazano, że podstawowe znaczenie w realizowanym procesie ma zastosowana ilość pierścieni, oraz prędkość obrotowa.The study presents analysis results of mixing process for two—component mixtures in a paddle mixer. The effect of exploitation parameters such as: rotation speed, mixing time and quantity of collars in a mixer was investigated. It was shown that a quantity of collars applied and rotation speed used are of great importance in this process

Influence of infrared radiation heat treatment of wheat seed on physical properties of milling products

W pracy przedstawiono wyniki badań wpływu obróbki cieplnej na wybrane właściwości fizyczne produktów przemiału. Obiektem badań było ziarno pszenicy odmiany Sukces. Ziarno o wilgotności początkowej 18% poddano działaniu promieni podczerwonych przez 30, 60, 90 i 120s. Przygotowane w ten sposób ziarno poddano przemiałowi a następnie oznaczone zostały wybrane parametry mąki i otrąb. Na podstawie wyników badań stwierdzono, że obróbka ziarna pszenicy promieniami podczerwonymi przed przemiałem powoduje znaczące zmiany wilgotności otrzymanych produktów przemiału oraz wpływa na wyciąg mąki oraz na gęstość usypową i kąt usypu.The study presents the results of the effect of heat treatment on chosen physical properties of milling products. The test object was a grain of wheat variety Sukces. Grain with initial moisture content of 18% were exposed to infrared radiation for 30, 60, 90 and 120s. Prepared in this way were subjected to a milling and then identified selected parameters of flour and bran. Based on the results of the research it was found that treatment of wheat grain prior to milling by infrared radiation causes significant changes in moisture content of the obtained milling products, affects the extraction rate, bulk density and angle of repose