Rescue of myeloid lineage-committed preprogenitor cells from cytomegalovirus-infected bone marrow stroma

The effect of murine cytomegalovirus on myelopoiesis was studied in long-term bone marrow culture to find an in vitro correlate for the lethal virus interference with bone marrow reconstitution (W. Mutter, M. J. Reddehase, F. W. Busch, H.-J. Bühring, and U. H. Koszinowski, J. Exp. Med. 167:1645-1658, 1988). The in vitro generation of granulocyte-monocyte progenitors (CFU-GM) discontinued after infection of the stromal cell layer, whereas the proliferation and differentiation of CFU-GM to granulocyte-monocyte colonies remained unaffected. A protocol was established to probe the functional integrity of earlier hematopoietic cells. Pre-CFU-GM (the progenitors of the CFU-GM) could be recovered from an infected bone marrow donor culture by transfer onto an inductive recipient stromal cell layer. Thus, at least in vitro, infection of bone marrow stroma appears to be the only cause of the defect in myelopoiesis

Assessment of bacteriological quality of ready to eat food (Meat pie) in Benin City metropolis, Nigeria

Eight triplicate samples of meat pie were randomly sampled from standard eatery and local kiosk in Benin City and analyzed microbiologically for the rates of Staphylococcus aureus and Escherichia coli. The mean microbial load on the fresh meat pie from the standard eatery ranged from 3x103 – 5x103cfu/g while the air preserved and refrigerated meat pie for (2 days) ranged between 2.3 x104 -3.8 x104 cfu/g and 8x 103-1.5 x104 cfu/g respectively. The mean microbial load of the fresh meat pie from the local kiosk ranged between 7x103-2.8x104 cfu/g while the air preserved and refrigerated meat pie for 2days ranged between 3x10-4 to too numerous to count (TNTC) and 1.3 x104 -2.8x104 cfu/g respectively. Six genera of the isolated bacteria include Staphylococcus, E. coli, klebsiella, Pseudomonas, Bacillus and Enterococcus. Statistical analysis of the mean microbial load showed a significant difference (P<0.05) between control and air preserved meat pie and no significant difference in the mean microbial load between control and refrigerated meat pie were (P>0.05)

The survival and growth of Bacillus cereus and Listeria monocytogenes, during the manufacture of Ricotta Salata cheese : a thesis presented in partial fulfilment of the requirements for the degree of Masters in Food Technology at Massey University, Palmerston North, New Zealand

This study was conducted with the following objectives: 1) to investigate the survival and growth of Bacillus cereus during the manufacture of Ricotta Salata cheese; and 2) to investigate the survival and growth of Listeria monocytogenes during the manufacture of Ricotta Salata cheese. The Ricotta Salata cheese was made by heating the whole milk to 95oC, and adding citric acid to coagulate the cheese curd. The cheese curd was inoculated with 7 log10 CFU/g B. cereus broth and 8 log10 CFU/g L. monocytogenes broth. After moulding for 12h, Ricotta Salata cheese was stored at 4oC for 1 week. During manufacture, the physico-chemical properties [pH, water activity (aw), and Sodium chloride (NaCl) concentration] and bacterial counts were recorded. The pH change fluctuated between 6.00 to 6.10 on the surface and 6.00 to 5.95 in the centre; the lowest aw was approximately 0.96 on the surface and 0.97 in the centre; and the highest NaCl concentration was 3.3% on the surface and 3% in the centre. The survival and growth of the two B. cereus strains (D1 and ATCC 13061) during the manufacture of Ricotta Salata cheese were similar. The B. cereus grew from approximately 5 log10 CFU/g to a maximum of 7.7 log10 CFU/g of cheese curd during moulding (20h at room temperature). The survival and growth of the two L. monocytogenes strains (W1 and ATCC 35152) during the manufacture of Ricotta Salata cheese were similar. The difference between the bacteria count on the surface and in the centre was very small. L. monocytogenes increased from 5 to 6 log10 CFU/g to a maximum of 8.6 log10 CFU/g during manufacture and maintained a level of around 8 log10 CFU/g in the final product. The Ricotta Salata supported the survival and growth of B. cereus and L. monocytogenes during manufacture. It is important to improve the management of process hygiene for reducing the environmental contamination. Ideally, some lethal treatments should be applied after the packaging of the cheese, to limit the contamination of Ricotta Salata with these two bacteria

PENGARUH AKTIVITAS WISATA TERHADAP JUMLAH BAKTERI ESCHERICHIA COLI DI SUMBER NYOLO DESA NGENEP KECAMATAN KARANGPLOSO MALANG SEBAGAI SUMBER BELAJAR BIOLOGI

There are many activities that occur in Sumber Nyolo, one of which is tourism activities. These activities will have an impact on the progress of the area and tourist locations, however, activities that occur continuously over a long period of time will cause changes in water quality. The aim of this research is to determine the effect of tourist activities on water quality in Sumber Nyolo, Ngenep Village, Karangploso District, Malang Regency. The method used for sampling uses an integrated technique, namely by mixing several samples taken on one channel, at several points at each station, there are 3 stations with 4 repetitions, twice on quiet days and twice on busy days. From this research, Escherichia coli bacteria were found at 9 CFU/100ml at the tourist location. Meanwhile, at station 1, 3 CFU/100ml were found, 4 CFU/100ml at station 2 and 1 CFU/100ml at station 3. After conducting multiple one-way ANOVA test, the effect of tourist activities on the Number of Escherichia coli Bacteria showed that there were no significant differences at each station. The results of this research can be used as a biology learning resource for class VII middle school students

Three Traditional Fermented Baobab Foods from Benin, Mutchayan, Dikouanyouri and Tayohounta: Preparation, Properties and Consumption

Forest food resources contribute significantly to food supply in areas where they grow. Three fermented baobab foods were studied: Dikouanyouri (from seeds, pH = 6.5); Tayohounta (from seed kernels, pH = 7), and Mutchayan (from baobab pulp and sorghum, pH = 4.2). Bacillus spp. (8.5 and 9.5 Log cfu /g) and lactic acid bacteria (8.9 and 8.4 Log cfu /g,) dominate in Dikouanyouri and Tayohounta, respectively. In Mutchayan, lactic acid bacteria (8.1 Log cfu/g) and yeasts (7.2 Log cfu/g) predominated. The arbitrary index of protein cleavage increases from 2.3% (unfermented products) to 13.7% in Dikouanyouri and 21.3% in Tayohounta, indicating significant protein degradation. Mutchayan is the most frequently consumed produc

Biofilm formation on enteral feeding tubes by Cronobacter sakazakii, Salmonella serovars and other Enterobacteriaceae

WHO (2007) recommended that to reduce microbial risks, powdered infant formula should be reconstituted with water at temperatures >70 °C, and that such feeds should be used within 2 h of preparation. However, this recommendation does not consider the use of enteral feeding tubes which can be in place for more than 48 h and can be loci for bacterial attachment. This study determined the extent to which 29 strains of Cronobacter sakazakii, Salmonella serovars, other Enterobacteriaceae and Acinetobacter spp. can adhere and grow on enteral feeding tubes composed of polyvinyl chloride and polyurethane. The study also included silver-impregnated tubing which was expected to have antibacterial activity. Bacterial biofilm formation by members of the Enterobacteriaceae was ca. 105-106 cfu/cm after 24 h. Negligible biofilm was detected for Acinetobacter gensp. 13; ca. 10 cfu/cm, whereas Cr. sakazakii strain ATCC 12868 had the highest biofilm cell density of 107 cfu/cm. Biofilm formation did not correlate with capsule production, and was not inhibited on silver-impregnated tubing. Bacteria grew in the tube lumen to cell densities of 107 cfu/ml within 8 h, and 109 cfu/ml within 24 h. It is plausible that in vivo the biofilm will both inoculate subsequent routine feeds and as the biofilm ages, clumps of cells will be shed which may survive passage through the neonate's stomach. Therefore biofilm formation on enteral feeding tubes constitutes a risk factor for susceptible neonates

A note on challenge trials to determine the growth of Listeria monocytogenes on mushrooms (Agaricus bisporus)

peer-reviewedIn the EU, food is considered safe with regard to Listeria monocytogenes if the number of micro-organisms does not exceed 100 colony forming units (cfu)/g throughout its shelf-life. Therefore, it is important to determine if a food supports growth of L. monocytogenes. Guidelines for conducting challenge tests for growth assessment of L. monocytogenes on foods were published by the European Union Reference Laboratory (EURL) in 2014. The aim of this study was to use these guidelines to determine if refrigerated, fresh, whole, closed-cap, prepackaged mushrooms (Agaricus bisporus) support the growth of L. monocytogenes. Three batches of mushrooms were artificially inoculated at approximately 100 cfu/g with a three-strain mix of L. monocytogenes and incubated for 2 days at 8°C followed by 4 days at 12°C. L. monocytogenes numbers were determined (in triplicate for each batch) on days 0, 2 and 6. Water activity, pH and total bacterial counts were also determined. There was no increase in the number of L. monocytogenes above the threshold of 0.5 log cfu/g in any of the replicates. In 8 of 9 replicates, the numbers decreased indicating that A. bisporus do not support the growth of L. monocytogenes. As the EU regulations allow < 100 cfu/g if the food cannot support growth of L. monocytogenes, the significance of this study is that mushrooms with < 100 cfu/g may be within the regulations and therefore, quantitative rather than qualitative determination may be required.Safefoo

Donor hematopoietic progenitor cells in nonmyeloablated rat recipients of allogeneic bone marrow and liver grafts

Background. Although the persistence of multilineage microchimerism in recipients of long-surviving organ transplants implies engraftment of migratory pluripotent donor stem cells, the ultimate localization in the recipient of these cells has not been determined in any species. Methods. Progenitor cells were demonstrated in the bone marrow and nonparenchymal liver cells of naive rats and in Brown Norway (BN) recipients of Lewis (LEW) allografts by semiquantitative colony-forming unit in culture (CFU-C) assays. The LEW allografts of bone marrow cells (BMC) (2.5xl08), orthotopic livers, or heterotopic hearts (abdominal site) were transplanted under a 2-week course of daily tacrolimus, with additional single doses on days 20 and 27. Donor CFU-C colonies were distinguished from recipient colonies in the allografts and recipient bone marrow with a donor-specific MHC class II monoclonal antibody. The proportions of donor and recipient colonies were estimated from a standard curve created by LEW and BN bone marrow mixtures of known concentrations. Results. After the BMC infusions, 5-10% of the CFU-C in the bone marrow of BN recipients were of the LEW phenotype at 14, 30, and 60 days after transplantation. At 100 days, however, donor CFU-C could no longer be found at this site. The pattern of LEW CFU-C in the bone marrow of BN liver recipients up to 60 days was similar to that in recipients of 2.5 x 108 BMC, although the donor colonies were only 1/20 to 1/200 as numerous. This was expected, because the progenitor cells in the passenger leukocytes of a single liver are equivalent to those in 1-5x106 BMC. Using a liquid CFU-C assay, donor progenitor cells were demonstrated among the nonparenchymal cells of liver allografts up to 100 days. In contrast, after heart transplantation, donor CFU-C could not be identified in the recipient bone marrow, even at 14 days. Conclusion. Under effective immunosuppression, allogeneic hematopoietic progenitors compete effectively with host cells for initial engraftment in the bone marrow of noncytoablated recipients, but disappear from this location between 60 and 100 days after transplantation, coincident with the shift of donor leukocyte chimerism from the lymphoid to the nonlymphoid compartment that we previously have observed in this model. It is possible that the syngeneic parenchymal environment of the liver allografts constitutes a privileged site for persistent progenitor donor cells