Feed cost is a major impediment to commercial poultry production in the South Pacific region because traditional feed ingredients (grains and oilseeds) are not grown in the region and imported at high price. As a result, meat has to be imported, which in Fiji increased by 69% between 2010 and 2011 (Diarra, 2017). Samoa was valued at about US$ 17 million or 87% of total cost of meat import in the country in 2012 and 2013. Several ingredients, which are available locally, could be included to reduce feed cost in the region. By-products of root/tuber harvest (peels and leaves), low value crops, fruits and by-products (peels and pulps), oil cakes (copra and palm kernel), by-products from the brewery, livestock/poultry slaughter, hatchery and fish processing and insect meal are readily available in most countries of the region. With adequate processing and correct diet formulation, these materials could replace reasonable proportions of the conventional energy and protein ingredients and reduce feed cost. Several factors including the type and source of material, processing method, diet composition, species, age and class of poultry affect the dietary recommendations of alternative ingredients. Currently however, the use of these resources in feed production in the region is limited due to lack of processing and analytical facilities, likely presence of antinutritional substances and poor knowledge on their nutritive value. Continued research into processing technology, regular training for farmers and extension staff and establishment of community owned feed processing units for optimum utilisation of locally available resources will benefits the poultry industry in the region.

We investigate the effects of toxins on the multiple coexistence solutions of an unstirred chemostat model of competition between plasmid-bearing and plasmid-free organisms when the plasmid-bearing organism produces toxins. It turns out that coexistence solutions to this model are governed by two limiting systems. Based on the analysis of uniqueness and stability of positive solutions to two limiting systems, the exact multiplicity and stability of coexistence solutions of this model are established by means of the combination of the fixed-point index theory, bifurcation theory and perturbation theory.

Kefir is a dairy product obtained by fermentation of milk with a complex microbial population and several health-promoting properties have been attributed to its consumption. In this work, we tested the ability of different kefir-isolated bacterial and yeast strains (Lactobacillus kefir, Lb. plantarum, Lactococcus lactis subps. lactis, Saccharomyces cerevisiae and Kluyveromyces marxianus) or a mixture of them (MM) to antagonise the cytopathic effect of toxins from Clostridium difficile (TcdA and TcdB). Cell detachment assays and F-actin network staining using Vero cell line were performed. Although incubation with microbial cells did not reduce the damage induced by C. difficile spent culture supernatant (SCS), Lc. lactis CIDCA 8221 and MM supernatants were able to inhibit the cytotoxicity of SCS to Vero cells. Fraction of Lc. lactis CIDCA 8221 supernatant containing components higher than 10 kDa were responsible for the inhibitory activity and heating of this fraction for 15 min at 100 °C completely abrogated this ability. By dot-blot assay with anti-TcdA or anti-TcdB antibodies, concentration of both toxins seems to be reduced in SCS treated with Lc. lactis CIDCA 8221 supernatant. However, protective effect was not affected by treatment with proteases or proteases-inhibitors tested. In conclusion, we demonstrated that kefir-isolated Lc. lactis CIDCA 8221 secreted heat-sensitive products able to protect eukaryotic cells from cytopathic effect of C. difficile toxins in vitro. Our findings provide new insights into the probiotic action of microorganisms isolated from kefir against virulence factors from intestinal pathogens.

Clostridium botulinum toxins, the most poisonous substance known to humankind, are considered to be a [US] Centers for Disease Control and Prevention Category A bioterrorist agent. Despite this concern, little has been published with regard to the tactical aspects of triaging a mass-casualty event involving botulism victims arriving at an emergency department. Because neuromuscular-ventilatory failure is a principal reason for botulism's early morbidity and mortality, using a quick and sensitive test to evaluate this possibility is imperative. The purpose of this article is to propose the adoption of the Single-Breath-Count Test (SBCT). The ease and validity of the use of the SBCT in evaluating complications associated with various neuromuscular disorders make it an attractive adjunct for triage during a mass-casualty incident due to botulism. While education, immune globulin, antitoxin, and invasive airway techniques are well-recognized steps in treating botulism, incorporating a time-honored technique such as the SBCT, will be an important addition to the triage process.

A gene, CRP136, from the intestinal protozoan parasite Giardia duodenalis, expressed at a high level in a metronidazole-resistant line, encodes a 136 kDa protein with 23 copies of a 40 amino acid repeat. The protein is cysteine-rich and has the typical membrane-spanning region and CXXC amino acid motifs of a family of Giardia cysteine-rich surface proteins (CRSPs). The repeat unit in CRP136, shares 57% homology with the gene encoding the precursor of the sarafotoxins, a group of snake toxins from the burrowing adder known to cause symptoms similar to those of humans acutely infected with Giardia. The sarafotoxins are low molecular weight sulphydryl cross-linked peptides which are proteolytically cleaved from a precursor polyprotein. CRP136 has homology over the entire length of the sarafotoxin precursor, and the repeats are of the same length. Thus CRP136 represents the first evidence for a potential Giardia toxin. The genomic copy number of CRP136 appears to be the same in both the parent and drug-resistant lines and expression of this gene, and at least one other, is associated with a conserved partial duplication, but not amplification, of one chromosome.

Several experiments using a self-regulated system were conducted to define the factors likely to influence the uptake of paralytic shellfish poison (PSP) by oysters in the Penzé estuary (France, Brittany). Each 4-day experiment was carried out in a recirculated sea water system using 15 Pacific oysters (Crassostrea gigas) separated from each other and supplied with unfiltered natural seawater containing alternatively toxic (Alexandrium minutum) or non-toxic (Skeletonema costatum) algal diets. The food supply and exposure times to toxic diets were determined according to field studies of the upstream and downstream movement of patches containing A. minutum. The experimental parameters corresponded roughly to the hydrological conditions generally observed in June when tidal coefficients are lowest and blooms occur: (i) A. minutum concentrations in sea water of 200, 5000 and 10 000 cell ml−1; (ii) inorganic matter consisting of 5 and 15 mg L−1 of calcinated muddy sediments; and (iii) low and high tide salinities of 25 and 35‰, respectively. Significant experimental contamination (greater than the 80 µg STX equiv. 100 g-1 sanitary threshold) occurred after 4 days of exposure for the monospecific A. minutum diet (20-200 cell ml−1) and alternated A. minutum and S. costatum diets (5000 and 20 000 cell ml−1, respectively). Contamination levels were less than the sanitary threshold for alternated A. minutum/S. costatum diets of 200 and 20 000 cell ml−1, respectively, and for a monospecific A. minutum diet (1000−10 000 cell ml−1). In the last case, the accumulation rate was quite low, possibly because of inhibition of the filtration rate related to a lower biodeposit production rate and decreased feeding time activity. The addition of inorganic matter appeared to play a significant role in the observed increase of toxin uptake, whereas salinity was not a determining factor for toxin accumulation rates. These last observations were corroborated by statistical analysis and stepwise multiple linear regressions integrating all or some of the experimental parameters.

A 58 kDa excretory–secretory product (ESP) of Giardia lamblia has been characterized. The ESP was purified over 508-fold by a combination of ammonium sulphate precipitation and sequential chromatography on affinity matrix and a gel filtration column. The homogeneity of the purified protein was established by sodium dodecyl sulphate polyacrylamide gel electrophoresis (Mr, 58 kDa) and analytical isoelectrophoresis (pI 4·75). The purified protein was recognized by the pooled sera of G. lamblia-positive patients as well as an antiserum raised against crude Giardia extract, thus indicating it to be an immunodominant parasite product. The ESP was found to agglutinate rabbit erythrocytes. The haemagglutinating activity of this protein was inhibited strongly by thyroglobulin, fetuin, asialofetuin and monosialoganglioside but not by simple sugars. The purified protein was characterized immunochemically and was found to be heat stable as well as protease sensitive. Lectin-binding studies of the purified ESP and its sensitivity to periodic-acid silver staining as well as to metaperiodate treatment clearly indicated its glycoprotein nature. The major localization site of the ESP was found to be on the surface of the parasite as revealed by flow cytometric analysis. Further, this glycoprotein induced fluid accumulation in ligated rabbit ileal loops and revealed a positive skin permeability reaction in the rabbit.

The streptococcal pyrogenic toxins A, B, and C (SPEA, SPEB, and SPEC) are responsible for the fever, rash, and other toxicities associated with scarlet fever and streptococcal toxic shock syndrome. This role, together with the ubiquity of diseases caused by Streptococcus pyogenes, have prompted structural analyses of SPEA by several groups. Papageorgiou et al. (1999) have recently reported the structure of SPEA crystallized in the absence of zinc. Zinc has been shown to be important in the ability of some staphylococcal and streptococcal toxins to stimulate proliferation of CD4+ T-cells. Since cadmium is more electron dense than zinc and typically binds interchangeably, we grew crystals in the presence of 10 mM CdCl2. Crystals have been obtained in three space groups, and the structure in the P212121 crystal form has been refined to 1.9 Å resolution. The structural analysis revealed an identical tetramer as well as a novel tetrahedral cluster of cadmium in all three crystal forms on a disulfide loop encompassing residues 87–98. No cadmium was bound at the site homologous to the zinc site in staphylococcal enterotoxins C (SECs) despite the high structural homology between SPEA and SECs. Subsequent soaking of crystals grown in the presence of cadmium in 10 mM ZnCl2 showed that zinc binds in this site (indicating it can discriminate between zinc and cadmium ions) using the three ligands (Asp77, His106, and His110) homologous to the SECs plus a fourth ligand (Glu33).

Une recherche de toxicité a été réalisée sur dix-huit souches isolées à partir d'efflorescences de cyanobactéries récoltées dans l'Ouest de la France et deux souches provenant de cultures de collection. Un biotest basé sur la sensibilité de larves d'une crevette marine Artemia salina a été développé et comparé à des bioessais sur souris, outil de référence pour la détection des toxines de cyanobactéries. Parmi les souches provenant du milieu naturel, six se sont avérées hépatotoxiques par les bioessais sur souris. Pour l'hépatotoxicité, les réponses du test A. salina recouvrent celles données par le test souris.