Bradykinin-related peptides in the venom of the solitary wasp Cyphononyx fulvognathus

Bradykinin (BK) and its related peptides are widely distributed in venomous animals, including wasps. In fact, we have previously purified a novel BK-related peptide (BRP) named Cd-146 and the threonine6-bradykinin (Thr6-BK) from the venom of the solitary wasp Cyphononyx fulvognathus. Further survey of this same wasp venom extract allowed the structural characterization of two other novel BRPs, named here as fulvonin and cyphokinin. Biochemical characterization performed here showed that although the high primary structure similarity observed with BK, these wasp peptides are not good substrates for angiotensin I-converting enzyme (ACE) acting more likely as inhibitors of this enzyme. In pharmacological assays, only those more structurally similar to BK, namely cyphokinin and Thr6-BK, were able to promote the contraction of guinea-pig ileum smooth muscle preparations, which was completely blocked by the B2 receptors antagonist HOE-140 in the same way as observed for BK. Only fulvonin was shown to potentiate BK-elicited smooth muscle contraction. Moreover, the 2 new wasp BRPs, namely fulvonin and cyphokinin, as well as Cd-146 and Thr6-BK, showed hyperalgesic effect in the rat paw pressure test after intraplantar injection. This effect was shown here to be due to the action of these peptides on BK receptors, since the hyperalgesia induced by both Cd-146 and fulvonin was blocked by B1 receptor antagonist, while the effect of both cyphokinin and Thr6-BK was reversed by B2 antagonist. This data give support to a better understanding of the function and targets of the kinin-related peptides widely found in several insect venoms.

Food poisoning associated with pumilacidin-producing Bacillus pumilus in rice.

Food poisoning caused by other Bacillus species than B. cereus has been described, but the toxins involved have rarely been isolated. Endospores will survive heat treatment and will germinate and multiply in cooked foods producing toxins under appropriate conditions. We describe a small food poisoning outbreak where three people became ill after a dinner in a Chinese restaurant. Acute symptoms including dizziness, headache, chills and back pain developed during the meal, and a few hours later they got stomach cramps and diarrhoea which lasted for several days. Cooked, reheated rice was the prime suspect of the food poisoning, and from the rice large numbers of Bacillus pumilus were isolated. The isolated B. pumilus strain was found to produce a complex of lipopeptides known as pumilacidins with the highest amounts produced at 15 degrees C. This is the first report on isolation of a pumilacidin-producing B. pumilus strain from food implicated in food poisoning and characterization of the organism and the toxin complex involved.

Analysis of the role of heat shock protein (Hsp) molecular chaperones in polyglutamine disease.

Polyglutamine (polygln) diseases are a group of inherited neurodegenerative disorders characterized by protein misfolding and aggregation. Here, we investigate the role in polygln disease of heat shock proteins (Hsps), the major class of molecular chaperones responsible for modulating protein folding in the cell. In transfected COS7 and PC12 neural cells, we show that Hsp40 and Hsp70 chaperones localize to intranuclear aggregates formed by either mutant ataxin-3, the disease protein in spinocerebellar ataxia type 3/Machado-Joseph disease (SCA3/MJD), or an unrelated green fluorescent protein fusion protein containing expanded polygln. We further demonstrate that expression of expanded polygln protein elicits a stress response in cells as manifested by marked induction of Hsp70. Studies of SCA3/MJD disease brain confirm these findings, showing localization of Hsp40 and, less commonly, Hsp70 chaperones to intranuclear ataxin-3 aggregates. In transfected cells, overexpression of either of two Hsp40 chaperones, the DNAJ protein homologs HDJ-1 and HDJ-2, suppresses aggregation of truncated or full-length mutant ataxin-3. Finally, we extend these studies to a PC12 neural model of polygln toxicity in which we demonstrate that overexpression of HDJ-1 suppresses polygln aggregation with a parallel decrease in toxicity. These results suggest that expanded polygln protein induces a stress response and that specific molecular chaperones may aid the handling of misfolded or aggregated polygln protein in neurons. This study has therapeutic implications because it suggests that efforts to increase chaperone activity may prove beneficial in this class of diseases.

Middle molecules: toxicity and removal by hemodialysis and related strategies.

Renal failure results in the retention of metabolites which may arbitrarily be grouped according to their molecular weight: low (< 300 daltons molecular weight), middle (300-15,000 daltons), and high (> 15,000 daltons). Opinion in respect to the relative importance of these groups varies. Initially it was thought that small molecules were important. In the mid-1970s, investigators identified the possible pathophysiological role of middle molecules. However, since positive identification of such molecules was difficult, opinion has shifted back in favor of small molecules, and little attention, with the exception of beta 2 microglobulin, has been paid to middle molecules and their removal by hemodialysis and related therapies. In this review current knowledge regarding middle molecules identified as uremic toxins and their removal by hemodialysis and associated therapies are discussed.

The pathogenesis of gluten-sensitive enteropathy.

Gluten-sensitive enteropathy is characterized by flattening of intestinal villi and malabsorption caused by the toxic effect of gluten, a wheat protein. Gluten activates an endogenous mechanism of toxicity that may be the local mucosal immune system: local mucosal immunoglobulin and antigluten antibody production occur soon after gluten ingestion. Approximately 80% of patients with this disease possess HL-A8, a second segregant series antigen. This association also occurs in dermatitis herpetiformis, a disease with vesicular skin lesions and gluten-sensitive flattening of intestinal villi. The association suggests that the fundamental abnormality in enteropathy is a binding reaction involving gluten protein and a binding site on a cell surface, determined in part by the histocompatibility gene; this reaction then results in a local mucosal immune response to gluten. Alternatively, the fundamental abnormality may be the presence of an abnormal immune-response gene linked to the HL-A8 gene or acting in concert with it; this immune-response gene results in local mucosal production of antigluten antibody.