Stimulation of the growth of cutaneous strains of Peptococcus saccharolyticus by iron, haematin and blood

The growth of nine strains of Peptococcus saccharolyticus was assessed quantitatively by culture Trypticase Soy/yeast extract/Tween 80 agar (TSY-TW) with and without supplementation with iron or haematin and on blood agar, in aerobic, reduced 02 (3% O2 with 8% CO2, 8% H2 and 81% N2) and anaerobic atmospheres. All strains grew better anaerobically and under reduced O2 conditions than aerobically on supplemented or unsupplemented TSY-TW.Supplementation of TSY-TW with iron or haematin resulted in an average 4.4-fold increase in bacterial count in a reduced O2 atmosphere and an average 4.2-fold increase under anaerobic conditions. Under aerobic conditions the increase in count ranged from O to greater than 5000-fold, as some strains failed to grow on unsupplemented TSY-TW but responded well to the supplements of iron or haematin. The highest bacterial counts were obtained on Columbia blood agar incubated anaerobically. However, P. saccharolyticus failed to grow aerobically on plain or heated Columbia blood agar with or without supplements. TSY-TW blood agar supported the growth of the one strain tested under all three atmospheric conditions. The type strain (ATCC 14953) differed from all others in its failure to grow aerobically or in a reduced O2 atmosphere on supplement or unsupplemented media. Colony size varied greatly on different media, in different atmospheres and from strain to strain, being greatest in a reduced O2 atmosphere on Columbia blood agar. There was no correlation between the viable bacterial count and colony size.     

On the formation of a dicloxacillin-p-hydroxymercuribenzoate suicide complex mediated by beta-lactamase I from Bacillus cereus

p-Hydroxymercuribenzoate is a non-competitive inhibitor of beta-lactamase I from Bacillus cereus and also, after preliminary preincubation, an inactivator of the enzyme. Submitted to the simultaneous action of PCMB plus dicloxacillin, the enzyme completely loses its activity. Extensive dialysis can restore the enzymatic activity only if preincubation had been carried out with either PCMB or dicloxacillin but not if both inhibitors had been simultaneously present. Mercaptoethanol protects the enzyme from the action of PCMB, but not from the severe inactivation caused by dicloxacillin-PCMB mixtures. All these data suggest the formation of a complex between PCMB and the acyl-enzyme intermediate generated upon hydrolysis of the beta-lactam bond of dicloxacillin.     

A comparison of the effects of metabolic inhibitors upon direct and antibody-dependent lymphocyte mediated cytotoxicity

The effect of metabolic inhibitors upon the lysis of allogeneic lymphocyte target cells by cytotoxic T lymphocytes and nonimmune lymphocyte K cells were studied by using identical culture conditions. Inhibition of lysis in both systems was induced by cycloheximide, puromycin, actinomycin D, diisopropylfluorophosphate, 2-deoxyglucose, antimycin A, oligomycin, and cytochalasins A and B, whereas ouabain and mitomycin C did not diminish lysis in either system. The strikingly parallel responses to a variety of agents that alter cellular processes suggest that both forms of lysis utilize similar mechanisms.     

Cellular components of allograft rejection: identity, specificity, and cytotoxic function of cells infiltrating acutely rejecting allografts.

Functioning mononuclear cells have been harvested from heterotopic rat cardiac allografts during maximal transplant cellular infiltration. T cells, identified by a T cell-specific absorbed rabbit anti-rat brain serum, constituted two-thirds of the total cells recovered. Approximately 20% of the infiltrating cells bear and synthesize surface immunoglobulin. Macrophages, identified by latex ingestion and morphologic and cytochemical techniques, comprise 9% of the graft infiltrate. Donor-specific cytotoxic T lymphocytes are concentrated within the graft. A separate population of Fc receptor-positive recovered cells mediate antibody-dependent LMC (Ab-LMC). Neither effector cell was adherent or phagocytic. These studies have conclusively established that cytotoxic T lymphocytes accumulate within rejecting allografts; however, the enriched presence of cytotoxic T cells within the grafts is not fully dependent upon antigen recognition per se, since Lew animals grafted with both BN and BUF hearts have Lew anti-BN and Lew anti-BUF killer cells in each graft.     

Bases and spaces: resources on the web for accessing the draft human genome - II - After publication of the draft

The volume of human genome sequence and the variety of web-based tools to access it continue to grow at an impressive rate, but a working knowledge of certain key resources can be sufficient to get the most from your genome. This article provides an update to Genome Biology 2000, 1(4):reviews2001.1-2001.5.