Stability enhancement for peptide analysis by electrospray using the triple quadrupole mass spectrometer

Electrospray ionization sources, used with triple quadrupole mass spectrometers from PE/Sciex (API III+), Micromass (Quattro II), and Finnigan (TSQ 7000), were modified with a 35-gauge stainless steel needle. The dimensions of the needle were 63 microm i.d. by 145 microm o.d. with variable length, depending on the specific instrument. This modification led to enhanced signal stability, improved signal/noise ratios, and lowered sample consumption for a wide range of peptides. Stable baselines were observed with flow rates in the range of 50 nL/min to 5 microL/min. An alternative design, based on a metal wire housed within a fused silica capillary, led to the most stable signals of all during infusion, but caused excessive peak broadening with capillary chromatography. The Finnigan interface was further modified with an external postcolumn addition tee, used in conjunction with capillary liquid chromatography columns of 30 and 50 microm internal diameter. The best results with the modified Finnigan interface were acquired using the 50-microm column at a flow rate of 150 to 200 nL/min.

Regulation of lipid A modifications by Salmonella typhimurium virulence genes phoP-phoQ

Bacterial pathogenesis requires proteins that sense host microenvironments and respond by regulating virulence gene transcription. For Salmonellae, one such regulatory system is PhoP-PhoQ, which regulates genes required for intracellular survival and resistance to cationic peptides. Analysis by mass spectrometry revealed that Salmonella typhimurium PhoP-PhoQ regulated structural modifications of lipid A, the host signaling portion of lipopolysaccharide (LPS), by the addition of aminoarabinose and 2-hydroxymyristate. Structurally modified lipid A altered LPS-mediated expression of the adhesion molecule E-selectin by endothelial cells and tumor necrosis factor-alpha expression by adherent monocytes. Thus, altered responses to environmentally induced lipid A structural modifications may represent a mechanism for bacteria to gain advantage within host tissues.

Leadership and vision in the NHS: how do we create the "vision thing"?

The development of NHS trusts has been a major part of the NHS reforms in the United Kingdom. The creation of trust boards has coincided with significant pressures from the combined forces for change and consolidation within publicly financed health care in the UK. The development of a long term strategic vision for trusts to ensure long-term survival is imperative. Considers evidence from international researchers and translates this into the context of NHS trusts. Discusses how they define and identify vision and ensure that vision building can be communicated and understood by key stakeholders within and outside the organization. Offers several practical suggestions on how their vision can be monitored and evaluated within the organization.

Inhibition of ICE family proteases by baculovirus antiapoptotic protein p35

The baculovirus antiapoptotic protein p35 inhibited the proteolytic activity of human interleukin-1 beta converting enzyme (ICE) and three of its homologs in enzymatic assays. Coexpression of p35 prevented the autoproteolytic activation of ICE from its precursor form and blocked ICE-induced apoptosis. Inhibition of enzymatic activity correlated with the cleavage of p35 and the formation of a stable ICE-p35 complex. The ability of p35 to block apoptosis in different pathways and in distantly related organisms suggests a central and conserved role for ICE-like proteases in the induction of apoptosis.

Hemolytic, but not cell-invasive activity, of adenylate cyclase toxin is selectively affected by differential fatty-acylation in Escherichia coli

Adenylate cyclase toxin from Bordetella pertussis requires posttranslational acylation of lysine 983 for the ability to deliver its catalytic domain to the target cell interior and produce cyclic adenosine monophosphate (cell-invasive activity) and to form transmembrane channels (hemolytic activity). When the toxin is expressed in Escherichia coli, it has reduced hemolytic activity, but comparable cell-invasive activity to that of adenylate cyclase toxin from B. pertussis. In contrast to the native protein from B. pertussis, which is exclusively palmitoylated, recombinant toxin from E. coli is acylated at lysine 983 with about 87% palmitoylated and the remainder myristoylated. Furthermore, the recombinant toxin contains an additional palmitoylation on approximately two-thirds of the lysines at position 860. These observations suggest that the site and nature of posttranslational fatty-acylation can be dictated by the bacterial host used for expression and can have a significant, but selective, effect on protein function.

Multiplicity of N-terminal structures of medium-chain alcohol dehydrogenases. Mass-spectrometric analysis of plant, lower vertebrate and higher vertebrate class I, II, and III forms of the enzyme

Ten different alcohol dehydrogenases, representing several classes of the enzyme and a wide spread of organisms, were analyzed for patterns of N-terminal structures utilizing a combination of conventional and mass spectrometric peptide analysis. Results show all forms to be N-terminally acetylated and allow comparisons of now 40 such alcohol dehydrogenases covering a large span of forms and origins. Patterns illustrate roles of acetylation in proteins in general, define special importance of the class I N-terminal acetylation, and distinguish separate acetylated structures for all classes, as well as a common alcohol dehydrogenase motif.

Identification and characterization of ICH-2, a novel member of the interleukin-1 beta-converting enzyme family of cysteine proteases

Interleukin-1 beta converting enzyme (ICE) is a cytoplasmic cysteine protease required for generating the bioactive form of the interleukin-1 beta cytokine from its inactive precursor. We report the identification of ICH-2, a novel human gene encoding a member of the ICE cysteine protease family, and characterization of its protein product. ICH-2 mRNA is widely expressed in human tissues in a pattern similar to, but distinct from, that of ICE. Overexpression of ICH-2 in insect cells induces apoptosis. Purified ICH-2 is functional as a protease in vitro. A comparison of the inhibitor profiles and substrate cleavage by ICH-2 and ICE shows that the enzymes share catalytic properties but may differ in substrate specificities, suggesting that the two enzymes have different functions in vivo.

Internal lysine palmitoylation in adenylate cyclase toxin from Bordetella pertussis

A number of bacterial protein toxins, including adenylate cyclase (AC) toxin from Bordetella pertussis, require the product of an accessory gene in order to express their biological activities. In this study, mass spectrometry was used to demonstrate that activated, wild-type AC toxin was modified by amide-linked palmitoylation on the epsilon-amino group of lysine 983. This modification was absent from a mutant in which the accessory gene had been disrupted. A synthetic palmitoylated peptide corresponding to the tryptic fragment (glutamine 972 to arginine 984) that contained the acylation blocked AC toxin-induced accumulation of adenosine 3',5'-monophosphate, whereas the non-acylated peptide had no effect.

Isolation and identification of a cardioactive peptide from Tenebrio molitor and Spodoptera eridania

We isolated several cardioactive peptides from extracts of whole heads of the mealworm, Tenebrio molitor, and the southern armyworm, Spodoptera eridania, using a semi-isolated heart of Manduca sexta for bioassay. We have now isolated from each species the peptide with the strongest effect on rate of contraction of the heart. The peptides were identified using micro Edman sequencing and mass spectrometric methods. This cardioactive peptide has the same primary structure from both species: Pro-Phe-Cys-Asn-Ala-Phe-Thr-Gly-Cys-NH2, a cyclic nonapeptide which is identical to crustacean cardioactive peptide (CCAP) originally isolated from the shore crab, Carcinus maenas, and subsequently isolated from Locusta migratoria and Manduca sexta. This is additional evidence that CCAP has widespread occurrence in arthropoda.

Dioxin intoxication from chronic exposure of horses to pentachlorophenol-contaminated wood shavings

Investigations into the cause of health problems on a horse-breeding farm led to the discovery of high concentrations (630 to 9,810 mg/kg of bedding) of pentachlorophenol in wood shavings used as bedding for horses over a period of 2 to 4 years. Toxicologic signs in the horses were characteristic of toxic effects associated with exposure of polychlorinated dibenzo-p-dioxins and dibenzofurans. Tissue residue analysis confirmed presence of toxic polychlorinated dibenzo-p-dioxin and dibenzofuran isomers known to be in pentachlorophenol, substantiating the bioavailability of polychlorinated dibenzo-p-dioxins and dibenzofurans in the wood shavings. The findings provide evidence that residue concentrations in the range of 2 ng/g of toxic polychlorinated dibenzo-p-dioxin isomers in liver or fat correlate with toxicologic effects in horses.

Survival of cultured allogeneic keratinocytes transplanted to deep dermal bed assessed with probe specific for Y chromosome

To determine the survival of cultured allogeneic keratinocytes transplanted to a deep dermal bed 24 tattoos that had been removed by deep shave excision in 19 patients were grafted with sheets of cultured allogeneic keratinocytes from donors of the opposite sex. Cells carrying the Y chromosome were identified in biopsy specimens taken from the graft site by in situ DNA hybridisation with a biotinylated Y probe (pHY 2.1) and visualised with a technique using immunoperoxidase. The cultured allograft sites were biopsied one, two, and three weeks after transplantation. No male cells were identified in any biopsy specimen from female patients who were given transplants of male cultured keratinocytes, and all biopsy specimens from male patients, who received female cultured keratinocytes, showed percentages of male cells within the normal range for male skin. The beneficial effects of cultivated allogeneic keratinocytes result from effects on wound healing other than forming a successful graft that "takes."

The effects of deliberate hypotension and foot down tilt on the incidence of deep vein thrombosis during plastic surgical operations: a pilot survey

The incidence of postoperative deep vein thrombosis (DVT) has been investigated in a group of 88 patients undergoing plastic surgical operations on the head and neck, and upper limb. Fifty-two cases were operated upon in the foot-down tilt position and 36 were horizontal. With the effects of blood pressure ignored as a possible contributory factor, the incidence of thrombosis in the latter group was 8-3% and was slightly higher in the tilted group (11-5%). Of those who were hypotensive, 3 developed DVT out of 41 (7-3%) who were tilted; whilst in the 11 who were normotensive and tilted 3 developed DVT, an incidence of 27-3%. Of those who were normotensive and operated flat the incidence of deep vein thrombosis was 8-0%, while in those subjected to a foot-down tilt it was 27-3%. The hypothesis has been advanced that frequent inflation and deflation of the cuff used for monitoring blood pressure in the hypotensive patients may release fibrinolytic activity and explain these differences. Age, sex and operative duration were not found to have an effect. It is concluded that the incidence of postoperative deep vein thrombosis in patients undergoing plastic surgical operations is lower than that found in general surgery, and is not worsened by deliberate hypotension.

Preliminary report on the comparative use of lyophilized homograft and xenograft in the closure of raw areas

Lyophilized allograft and xenograft appear to be equally effective for the temporary cover of raw areas1.

Lyophilized allograft has the disadvantage of occasionally separating into two layers when removed. One layer can easily be missed and inhibit the take of a subsequent autograft.

Lyophilized xenograft is easier to handle and more easily available. In spite of the many advantages shown to be associated with this method of treatment, it is still virtually unused in Great Britain and in many other parts of the world.