Growth and inactivation of Salmonella enterica and Listeria monocytogenes in broth and validation in ground pork meat during simulated home storage abusive temperature and home pan-frying

Ground pork meat with natural microbiota and inoculated with low initial densities (1-10 or 10-100 CFU/g) of Salmonella enter/ca or Listeria monocytogenes was stored under abusive temperature at 10 degrees C and thermally treated by a simulated home pan-frying procedure. The growth and inactivation characteristics were also evaluated in broth. In ground pork meat, the population of S. enter/ca increased by less than one log after 12 days of storage at 10 degrees C, whereas L. monocytogenes increased by 2.3 to 2.8 log units. No unusual intrinsic heat resistance of the pathogens was noted when tested in broth at 60 degrees C although shoulders were observed on the inactivation curves of L. monocytogenes. After growth of S. enter/ca and L. monocytogenes at 10 degrees C for 5 days to levels of 1.95 log CFU/g and 3.10 log CFU/g, respectively, in ground pork meat, their inactivation in the burger subjected to a simulated home pan-frying was studied. After thermal treatment S. enter/ca was undetectable but L. monocytogenes was recovered in three out of six of the 25 g burger samples. Overall, the present study shows that data on growth and inactivation of broths are indicative but may underestimate as well as overestimate behavior of pathogens and thus need confirmation in food matrix conditions to assess food safety in reasonably foreseen abusive conditions of storage and usual home pan-frying of meat burgers in Belgium

The neonicotinoid insecticide Imidacloprid repels pollinating flies and beetles at field-realistic concentrations

Neonicotinoids are widely used systemic insecticides which, when applied to flowering crops, are translocated to the nectar and pollen where they may impact upon pollinators. Given global concerns over pollinator declines, this potential impact has recently received much attention. Field exposure of pollinators to neonicotinoids depends on the concentrations present in flowering crops and the degree to which pollinators choose to feed upon them. Here we describe a simple experiment using paired yellow pan traps with or without insecticide to assess whether the commonly used neonicotinoid imidacloprid repels or attracts flying insects. Both Diptera and Coleoptera exhibited marked avoidance of traps containing imidacloprid at a field-realistic dose of 1 μg L-1, with Diptera avoiding concentrations as low as 0.01 μg L-1. This is to our knowledge the first evidence for any biological activity at such low concentrations, which are below the limits of laboratory detection using most commonly available techniques. Catch of spiders in pan traps was also slightly reduced by the highest concentrations of imidacloprid used (1 μg L-1), but catch was increased by lower concentrations. It remains to be seen if the repellent effect on insects occurs when neonicotinoids are present in real flowers, but if so then this could have implications for exposure of pollinators to neonicotinoids and for crop pollination. © 2013 Easton, Goulson

The pan-genome of Lactobacillus reuteri strains originating from the pig gastrointestinal tract

Background Lactobacillus reuteri is a gut symbiont of a wide variety of vertebrate species that has diversified into distinct phylogenetic clades which are to a large degree host-specific. Previous work demonstrated host specificity in mice and begun to determine the mechanisms by which gut colonisation and host restriction is achieved. However, how L. reuteri strains colonise the gastrointestinal (GI) tract of pigs is unknown. Results To gain insight into the ecology of L. reuteri in the pig gut, the genome sequence of the porcine small intestinal isolate L. reuteri ATCC 53608 was completed and consisted of a chromosome of 1.94 Mbp and two plasmids of 138.5 kbp and 9.09 kbp, respectively. Furthermore, we generated draft genomes of four additional L. reuteri strains isolated from pig faeces or lower GI tract, lp167-67, pg-3b, 20-2 and 3c6, and subjected all five genomes to a comparative genomic analysis together with the previously completed genome of strain I5007. A phylogenetic analysis based on whole genomes showed that porcine L. reuteri strains fall into two distinct clades, as previously suggested by multi-locus sequence analysis. These six pig L. reuteri genomes contained a core set of 1364 orthologous gene clusters, as determined by OrthoMCL analysis, that contributed to a pan-genome totalling 3373 gene clusters. Genome comparisons of the six pig L. reuteri strains with 14 L. reuteri strains from other host origins gave a total pan-genome of 5225 gene clusters that included a core genome of 851 gene clusters but revealed that there were no pig-specific genes per se. However, genes specific for and conserved among strains of the two pig phylogenetic lineages were detected, some of which encoded cell surface proteins that could contribute to the diversification of the two lineages and their observed host specificity. Conclusions This study extends the phylogenetic analysis of L. reuteri strains at a genome-wide level, pointing to distinct evolutionary trajectories of porcine L. reuteri lineages, and providing new insights into the genomic events in L. reuteri that occurred during specialisation to their hosts. The occurrence of two distinct pig-derived clades may reflect differences in host genotype, environmental factors such as dietary components or to evolution from ancestral strains of human and rodent origin following contact with pig populations

Mechanistic modeling of CO2 well leakage in a generic abandoned well through a bridge plug cement-casing gap

Both known and unmapped plugged and abandoned wells are potential leakage pathways for CO2 from geologic carbon sequestration (GCS) sites. Although many abandoned wells have cement bridge plugs installed to prevent leakage, the seal between the cement and the inner casing wall is subject to failure. In this study, we carried out detailed T2Well simulations of cases of sudden non-Darcy flow of CO2 and brine leakage up the gap between a cement plug and the inner steel casing wall that becomes a fully connected flow path during the post-injection period. The goal of our study was two-fold: (1) to understand the dynamics, rates, and the characteristic temporal signals associated with the onset of leakage through various gap-aperture sizes, and (2) to suggest potential monitoring strategies based on the findings. Simulation results show that the leakage of CO2 and brine upward is transient with interesting phase interference behavior. Time-dependent oscillatory flows with varying pressure, temperature, and flow rates of CO2 and brine show strong dependence on gap aperture. Phase-change and decompression lead to very low temperatures at the top of the well for gap apertures larger than 4 mm suggesting that remote thermal monitoring at the ground surface may be an effective way of monitoring even if well locations are not known a priori. Pressure in the well is also indicative of CO2 leakage. The temporal patterns of changing temperature and pressure may be useful diagnostic signals for leakage detection. Finally, these transient leakage signals may provide information on the cause of leakage and/or characteristics of the flow path that could inform effective remediation design and execution approaches

Color television system for a manned space base Progress report

Color television system for manned space statio

Comparative analysis of Lactobacillus gasseri from Chinese subjects reveals a new species-level taxa

peer-reviewedBackground Lactobacillus gasseri as a probiotic has history of safe consumption is prevalent in infants and adults gut microbiota to maintain gut homeostasis. Results In this study, to explore the genomic diversity and mine potential probiotic characteristics of L. gasseri, 92 strains of L. gasseri were isolated from Chinese human feces and identified based on 16 s rDNA sequencing, after draft genomes sequencing, further average nucleotide identity (ANI) value and phylogenetic analysis reclassified them as L. paragasseri (n = 79) and L. gasseri (n = 13), respectively. Their pan/core-genomes were determined, revealing that L. paragasseri had an open pan-genome. Comparative analysis was carried out to identify genetic features, and the results indicated that 39 strains of L. paragasseri harboured Type II-A CRISPR-Cas system while 12 strains of L. gasseri contained Type I-E and II-A CRISPR-Cas systems. Bacteriocin operons and the number of carbohydrate-active enzymes were significantly different between the two species. Conclusions This is the first time to study pan/core-genome of L. gasseri and L. paragasseri, and compare their genetic diversity, and all the results provided better understating on genetics of the two species

Comparison Study of Macropollutant Removal in River Water Using Conventional Treatment and Nanofiber Membrane-Based System

Abstract: High levels of nitrate (NO3) and phosphate (PO4) concentrations in water sources due to agricultural drainage or municipal disposal can generate eutrophication. It is characterized by blooms of either green or blue-green algae leading to significant drops in dissolved oxygen and frequently renders many fish and zooplankton species unable to survive in the water. In this study, the efforts to reduce total suspended solids (TSS), NO3, and PO4 pollutants in river water are evaluated using conventional treatment and membrane filtration systems as a comparison. Conventional water treatment process uses bar screening, flocculation-coagulation, and settling/sedimentation to remove pollutants; while membrane filtration system rejects a wide range of pollutants using pore exclusion. This study assessed electrospinning membrane filtration made of polyacrylonitrile (PAN) and polyacrylonitrile/polyethylene glycol-silver nanoparticle (PAN/PEG-Ag). The effectiveness of removing pollutant levels after going through a conventional type of water treatment and 12% PAN membrane (EM1), and 12% PAN-PEGAg 1% (EM2) showed the reduction level of TSS was 82.76%, 75.86%, 65.52 %, NO3 reduction was 73.97%, 85.62%, 83.19%, and PO4 reduction was 77.20%, 59.60%, 53.45%. The removal efficiency using pristine PAN membrane was 81.86%, 73.02% when using the conventional process, and 64.31% when using 12% PAN-1% PEGAg. After the conventional and membrane processes, TSS and nitrate level reductions were adequate, as seen from the set quality standard values, i.e., below 50 mg/L and 10 mg/L. Meanwhile, after both water treatments, the phosphate level did not meet the water quality standard, 0.2 mg/L, as regulated in the Government Regulation Number 22 of 2021.Abstrak: Konsentrasi nitrat (NO3) dan fosfat (PO4) yang tinggi dalam sumber air karena drainase pertanian atau pembuangan kota dapat menghasilkan eutrofikasi. Hal ini ditandai dengan mekarnya ganggang hijau atau biru-hijau yang menyebabkan penurunan oksigen terlarut yang signifikan dan sering membuat banyak ikan dan spesies zooplankton tidak dapat bertahan hidup di air. Dalam studi ini, upaya untuk mengurangi polutan total padatan tersuspensi (TSS), NO3, dan PO4 dalam air sungai dievaluasi menggunakan pengolahan konvensional dan sistem filtrasi membran sebagai pembanding. Proses pengolahan air konvensional menggunakan bar screening, flokulasi-koagulasi, dan pengendapan/sedimentasi untuk menghilangkan polutan; sementara sistem filtrasi membran merejeksi berbagai macam polutan menggunakan eksklusi pori. Studi ini menilai filtrasi membran elektrospinning yang terbuat dari polyacrilonitrile (PAN) dan polyacrilonitrile/polyethylene glycol-silver nanoparticle (PAN/PEG-Ag). Efektifitas penyisihan kadar pencemar setelah melalui jenis pengolahan air secara konvensional dan membran PAN 12% (EM1), dan PAN 12%-PEGAg 1% (EM2) menunjukkan tingkat reduksi dari TSS adalah 82,76%, 75,86%, 65,52%, reduksi NO3 adalah 73,97%, 85,62%, 83,19%, dan reduksi PO4 adalah 77,20%, 59,60%, 53,45%. Efisiensi penyisihan menggunakan membran PAN murni adalah 81,86%, 73,02% bila menggunakan proses konvensional, dan 64,31% bila menggunakan 12% PAN-1% PEGAg. Setelah proses konvensional dan membran, penurunan kadar TSS dan nitrat cukup baik, terlihat dari nilai baku mutu yang ditetapkan yaitu di bawah 50 mg/L dan 10 mg/L. Sedangkan setelah dilakukan kedua pengolahan air tersebut, kadar fosfat tidak memenuhi baku mutu air yaitu 0,2 mg/L sebagaimana diatur dalam Peraturan Pemerintah Nomor 22 Tahun 2021