Reduction of Acetylmethylcarbinol and Diacetyl to 2,3-Butylene Glycol by the citric acid fermenting streptococci of butter cultures

When acetylmethylcarbinol or diacetyl was added to a tomato bouillon culture of one of the citric acid fermenting streptococci normally present in butter cultures, there was a rapid disappearance of the added reagent and an increase in 2,3-butylene glycol. The amount of the glycol produced accounted, in a general way, for the acetylmethylcarbinol or diacetyl that disappeared. The added reagent did not usually disappear completely. In trials with acetylmethylcarbinol the change of the carbinol to the glycol was delayed when sulfuric acid was added in amounts to yield a pH of from 3.8 to 4.0. There was also a change of acetylmethylcarbinol or diacetyl to 2,3-butylene glycol when one of these reagents was added to a milk culture of one of the organisms. With the diacetyl there was an increase in the acetylmethylcarbinol as well as in the 2,3-butylene glycol, and the increase in the carbinol was greater than the increase in the glycol. The added reagent did not disappear completely in any of the trials. When various amounts of sulfuric acid were added to milk cultures of the organisms, acetylmethylcarbinol was not produced at the higher pH values but was produced at the lower values, while 2,3-butylene glycol was produced at both the higher and lower pH values. There was less of the glycol formed at the lower pH values than at the higher ones. The total molarities of acetylmethylcarbinol and 2,3-butylene glycol showed an increase as the pH was lowered, although there were some irregularities in the increase with one of the organisms. The addition of 0.65 percent citric acid to a milk culture of one of the organisms resulted in an increase in both acetylmethylcarbinol and 2,3-butylene glycol. The reduction of acetylmethylcarbinol, which had been added to a milk culture of one of the organisms, to 2,3-butylene glycol was not delayed by potassium nitrate in the quantity used but was delayed by the largest amount of hydrogen peroxide employed. In pure cultures of the citric acid fermenting streptococci which had been acidified with sulfuric acid to a pH of about 3.9, the addition of acetaldehyde or propionaldehyde increased the amount of acetylmethylcarbinol present after 96 hours at 21 °C. but decreased the amount of 2,3-butylene glycol and also commonly decreased the total molarities of the two compounds. These results suggest that the increased production of acetylmethylcarbinol is accounted for by a decrease in the reduction of the carbinol to the corresponding glycol, rather than to an aldehyde condensation involving, in part, the added aldehyde. In butter cultures the decrease in acetylmethylcarbinol was accompanied by an increase in 2,3-butylene glycol, and there was commonly an increase, from one examination to the next, in the total molarities of the two compounds. When ripened butter cultures were neutralized to a low acidity there was a rapid decrease in the acetylmethylcarbinol, and in some of the trials this was followed by an increase. The decrease in the carbinol was accompanied by a rapid increase in 2,3-butylene glycol, and there was also an increase in the total molarities of the two compounds. Hydrogen peroxide, in certain concentrations, delayed the reduction of acetylmethylcarbinol to 2,3-butylene glycol as did also 1 percent sodium fumarate or 12 percent sodium chloride. Ice water temperatures also delayed the reduction in either neutralized or unneutralized cultures, but the reduction was more rapid with neutralization than without

Hydroxyfurans and Their Biological Significance

Hydroxyfurans, particularly the mono- and di-β-substituted types (prepared from furans and by ring closure procedures) have been examined biologically, particularly for their growth stimulation effects on bacteria, yeasts and various higher plants. A discussion is included of the synthetic procedures and the proof of structure of the variously substituted hydroxyfurans

Criticism of the Use of Coomassie Brilliant Blue G-250 for the Quantitative Determination of Proteins

Peer Reviewe

Proton arc therapy increases the benefit of proton therapy for oropharyngeal cancer patients in the model based clinic

Background and purpose: In the model-based approach, patients qualify for proton therapy when the reduction in risk of toxicity (ΔNTCP) obtained with IMPT relative to VMAT is larger than predefined thresholds as defined by the Dutch National Indication Protocol (NIPP). Proton arc therapy (PAT) is an emerging technology which has the potential to further decrease NTCPs compared to IMPT. The aim of this study was to investigate the potential impact of PAT on the number of oropharyngeal cancer (OPC) patients that qualify for proton therapy.Materials and methods: A prospective cohort of 223 OPC patients subjected to the model-based selection procedure was investigated. 33 (15%) patients were considered unsuitable for proton treatment before plan comparison. When IMPT was compared to VMAT for the remaining 190 patients, 148 (66%) patients qualified for protons and 42 (19%) patients did not. For these 42 patients treated with VMAT, robust PAT plans were generated.Results: PAT plans provided better or similar target coverage compared to IMPT plans. In the PAT plans, integral dose was significantly reduced by 18% relative to IMPT plans and by 54% relative to VMAT plans. PAT decreased the mean dose to numerous organs-at-risk (OARs), further reducing NTCPs. The ΔNTCP for PAT relative to VMAT passed the NIPP thresholds for 32 out of the 42 patients treated with VMAT, resulting in 180 patients (81%) of the complete cohort qualifying for protons.Conclusion: PAT outperforms IMPT and VMAT, leading to a further reduction of NTCP-values and higher ΔNTCP-values, significantly increasing the percentage of OPC patients selected for proton therapy.</p

The Fate of Acetylmethylcarbinol and Diacetyl in Dairy Products

Butter cultures normally contain two distinct types of bacteria, (a) a typical lactic acid forming type (Streptococcus lactis) and (b) a type which is important from the standpoint of the production of satisfactory flavor and aroma and includes Streptococcus citrovorus and Streptococcus paracitrovorus

Op zoek naar de "ware" neerslag en verdamping; toetsing van de met het STONE 2.1-instrumentarium berekende verdamping aan literatuurgegevens en aan regionale waterbalansen, en de gevoeligheid van het neerslagoverschot op de uitspoeling van nutriënten

Het neerslagoverschot is van grote invloed op de door het STONE-instrumentarium berekende N- en P-belasting van grond- en oppervlaktewater. Naar de hiervoor meest bepalende processen neerslag en verdamping, zoals die voor STONE 2.1 als randvoorwaarden worden opgelegd of worden berekend, is een beperkte gevoeligheidsanalyse uitgevoerd. Daaruit volgt dat het niveau van de potentiële verdamping van grasland systematisch te hoog wordt berekend. De vergelijking met de verdampingsreducties volgens de HELP-tabel indiceren een te geringe berekende reductie voor droogtegevoelige zandgronden. Ook is een vergelijking gemaakt met gegevens uit de literatuur en met de verdamping als restpost van de waterbalansen van een aantal gebieden. Voor het Holocene deel van Nederland is er een goede overeenkomst; voor het Pleistocene deel van Nederland is de verdamping als restpost van de waterbalans enigszins lager dan de door STONE 2.1 berekende verdamping. Door het gedateerd zijn van historische gegevens en door de onbetrouwbaarheid van de waterbalansen zijn dit geen harde conclusie

Conversion of patellofemoral arthroplasty to total knee arthroplasty: A matched case-control study of 13 patients

Background and purpose The long-term outcome of patellofemoral arthroplasty is related to progression of femorotibial osteoarthritis with need for conversion to total knee arthroplasty. We investigated whether prior patellofemoral arthroplasty compromises the results of total knee arthroplasty