Factors affecting production and stability of the AcAFP antifungal peptide secreted by Aspergillus clavatus

We have previously reported the identification of a small, basic and cysteine-rich antifungal peptide (AcAFP) secreted by Aspergillus clavatus and shown its ability to prevent growth of various human- and plant-pathogenic filamentous fungi. In this study, we sought to determine the physiological/microbiological requirements to enhance the AcAFP production and the conditions influencing its stability. The maximum of AcAFP production was obtained when A. clavatus was grown on 2% glycerol as sole carbon source and 100 mM NaCl. The AcAFP expression was shown to be influenced by pH, being suppressed under acidic (pH 5) and strongly induced under alkaline conditions. The activity of the purified AcAFP was not affected by temperature; it loosed approximately 20% of its activity after 3 h at 100°C and was efficient through a large pH range (pH 5-12) with an optimum at pH 8. AcAFP activity decreased at high ionic strength and in the presence of 10 mM of divalent cations (Mn²⁺, Fe²⁺ and Ca²⁺).     

Echinocephalus caniculus n. sp. (Nematoda: Gnathostomatidae Railliet, 1895) from the lesser spotted dogfish Scyliorhinus canicula (L.) (Elasmobranchii: Scyliorhinidae Gill, 1862) off Tunisia,with a key to species of the genus Echinocephalus

Systematic Parasitology - Echinocephalus caniculus n. sp. (Nematoda, Gnathostomatidae Railliet, 1895) was isolated from the spiral valve of the lesser spotted dogfish Scyliorhinus canicula (L.)...     

Potential hazards associated with the consumption of Scombridae fish: Infection and toxicity from raw material and processing

Scombridae fish (tuna, bonito and mackerel) have significant ecological and economic values. They are very appreciated by consumers worldwide for their high-quality flesh and for their high nutritional value. However, consumption of Scombridae fish is potentially hazardous. Indeed, several cases of infections and toxicity linked to the consumption of Scombridae fish as raw, or processed food products have been reported worldwide. In this review, we presented the most common health risks associated with Scombridae fish consumption. Diseases associated with the consumption of these fish are generally infectious or toxic and are caused by biological hazards, such as bacteria, viruses, parasites or chemicals hazards that enter the body through contaminated fish (polycyclic aromatic hydrocarbons, histamine) or by physical contaminants, such as heavy metals. The risks of contamination exist throughout the food chain, from primary production to the preparation of products for consumption.     

Cloning and molecular modelling of turkey pancreatic lipase: structural explanation of the increased interaction power with lipidic interface

Starting from total pancreatic mRNAs, turkey pancreatic lipase (TPL) cDNA was synthesized by RT-PCR and cloned into the PGEM-T vector. Amino acid sequence of the TPL is compared to that of human pancreatic lipase (HPL). A 3-D structure model of TPL was built using the 3-D structure of HPL as template, given the high amino acid sequence homology between the two lipases. Based on this model, the enhanced interaction power of TPL, as compared to that of HPL, into a phosphatidylcholine monolayer film, could be explained. We concluded that an increase in the exposed hydrophobic residues on the surface of TPL would be responsible for an enhanced interaction with a lipidic interface.     

Immunocytochemical localization of scorpion digestive lipase

The scorpion hepatopancreas consists of digestive diverticula and interstitial tissue. A digestive diverticulum is composed of two differentiated cell types: the secretory zymogene-like cells and the digestive cells which are the most abundant. The scorpion digestive lipase (SDL) has been previously purified from scorpion hepatopancreas, but its cellular localization has not yet been established. Polyclonal antibodies specific to SDL were prepared and used in immunofluorescence and immunogold techniques to determine the cellular location of SDL. Our results clearly established that SDL was detected intracellularly in specific vesicles tentatively named (SDL+) granules of the digestive cells. No immunolabelling was observed in secretory zymogene-like cells. This immunocytolocalization indicates that lipid digestion might occur in specific granules inside the digestive cells, as suggested by previous studies on the scorpion digestive process.     

Use of Geotrichum candidum for olive mill wastewater treatment in submerged and static culture

The production of lignin peroxidase (LiP), manganese peroxidase (MnP) and lipases by Geotrichum candidum were performed in order to control the decolourisation and biodegradation of olive mill wastewater (OMW). Optimisation of different factors showed that dilution, carbon and ammonium concentrations significantly affected decolourisation and activities of ligniolytic peroxidases (LiP and MnP) on OMW. Moreover, addition of olive oil and agitation improved the lipase production. Batch and continuous OMW treatments in settler or bubble column bioreactors showed high COD and colour removal efficiencies of 60% and 50%, respectively. Lipolytic activity was greater in the batch bubble column whereas, LiP and MnP productions were improved in the settler. The performance of the continuous processes decreased with the decrease of hydraulic retention time (HRT). It has been shown that decolourisation and biodegradation decreased with an average of 40% and 45%, respectively, by decreasing the HRT from 4 d to 1.7 d.     

Lipid Peroxidation and Antioxidant System in the Tumor and in the Blood of Patients with Nasopharyngeal Carcinoma

Reactive oxygen species play a key role in cancer development by inducing and maintaining the oncogenic phenotypes of cancer cells. In this study, we examined lipid peroxidation and antioxidant enzymes activities in the blood and in the tumor of nasopharyngeal carcinoma patients. Plasma malondialdehyde, conjugated dienes, erythrocytes catalase, and superoxide dismutase activities have been measured in 30 untreated nasopharyngeal carcinoma patients and 30 controls on one hand. On the other hand, tumor malondialdehyde level, catalase, and superoxide dismutase activities have been measured in five nasopharyngeal carcinoma patients and compared with four controls. The lipid peroxidation was confirmed in the plasma by the high levels of malondialdehyde and conjugated dienes (p?<?0.001, respectively). Additionally, significantly higher concentrations of malondialdehyde were found in biopsies compared to the control group (p?<?0.001). In erythrocytes, superoxide dismutase activity was higher in patients than in controls (p?<?0.05), while it was unchanged in the tumor (p?>?0.05). Both erythrocytes and tumor catalase activities were significantly lower in patients than in controls (p?<?0.001, respectively). Statistical studies have shown a positive correlation between malondialdehyde level and IgA antibodies level against Epstein–Barr virus capsid antigen (p?<?0.05). In conclusion, we reported the presence of an oxidative stress in the blood and in the biopsies of nasopharyngeal carcinoma patients where Epstein–Barr virus seems to play a role.     

Enzymatic synthesis of green notes with hydroperoxide-lyase from olive leaves and alcohol-dehydrogenase from yeast in liquid/gas reactor

Hydroperoxide-lyase is a suitable enzyme for the biocatalytic production of six-carbon aldehydes which are responsible for the “green notes” in many fruits and vegetables. The hydroperoxide-lyase isolated from olive leaves is used in this work. The effects of pH, temperature, and substrate and enzyme concentrations on hexenals generation were optimized. The main objective of this paper consists on the elaboration of a biocatalytic procedure for the synthesis of flavors with green odor characteristics. For this purpose an enzymatic liquid/gas reactor, where the synthesis of C6-compounds was coupled to their extraction, has been proposed. Hexenals were produced in two steps: (1) 13 hydroperoxy-linolenic acid was produced from hydrolyzed linseed oil in presence of soybean lipoxygenase. (2) 3Z- and 2E-hexenals (up to 0.36 g kg⁻¹ of reaction medium) were produced from 13 hydroperoxy-linolenic acid in presence of olive hydroperoxide-lyase at 50% yield. The hexenals were successfully reduced into their corresponding alcohols by adding yeast cells Saccharomyces cerevisiae containing alcohol-dehydrogenase activity to the same reactor. Significant amounts of 3Z-hexenol (up to 3.54 g kg⁻¹ of olive leaves) were produced and extracted at a yield of 47.7% and with high purity when permeabilized yeast cells were used.     

Diagnostic value of an enzyme‐linked immunosorbent assay using the recombinant CT694 species‐specific protein of Chlamydia trachomatis

Aim: To study the performance of the CT694 protein in relation to the microimmunofluorescence (MIF) and the pELISA tests for the serodiagnosis of Chlamydia trachomatis infections. Methods and Results: The CT694 protein was produced as recombinant protein and was used as antigen in ELISA test for the detection of C. trachomatis IgG antibodies. The performance of the developed ELISA test was compared to the MIF test at two cut‐off values of 16 and 64, and to the specific pELISA test using a panel of 342 sera. These sera were from children MIF C. trachomatis and Chlamydophila pneumoniae negative, patients MIF C. pneumoniae positive, patients MIF C. trachomatis positive, patients suspected to have chlamydial infections diagnosed by the Cobas Amplicor test, healthy blood donors and prostitutes. Our results indicate that the developed ELISA test has performed better compared with the MIF and the pELISA tests. The highest performance was obtained when comparing the developed ELISA test in relation to the pELISA, yielding an overall sensitivity and specificity of 85% and 87% respectively. Conclusions: The CT694 ELISA showed the best performance when compared to the species‐specific pELISA test and may be used for the serodiagnosis of C. trachomatis infections. Significance and Impact of the Study: The CT694 ELISA test responds to the criteria of both sensitivity and specificity according to the MIF and pELISA tests and may be used for serodiagnosis of C. trachomatis infections.