Molecular bacterial characterization and free amino acids composition in Ivorian traditional fermented fish produced by two methods

The aim of this study was to show and compare the as yet unknown microbiological and biochemical composition of ??adjuevan??, an Ivorian traditional salted fermented fish that is produced by two main processing methods and consumed for its flavor. Method 1 uses the full fish and method 2 uses fish fillets. The pH was around 6 and the major organic acids were acetic and butyric acids in all adjuevan samples. The free amino acid profile varied according to the fermentation method, although the major free amino acids were valine, leucine, alanine, aspartic acid and glutamic acid, ranging in concentration from 101.7 to 745.4?mg/100?g, for both methods. Adjuevan produced using method 1 had the best composition of free amino acids. Lactic acid bacteria counts were between 6.0?×?10⁴ and 2.6?×?10⁵?cfu/g for method 1 and 5.9?×?10³ and 2.1?×?10⁴?cfu/g for method 2. Yeasts were detected in all samples. Microbial ecology analysis using PCR-denaturing gradient gel electrophoresis (DGGE) revealed the presence of more bacterial species than previously reported in fermented fish. Bacterial species varied according to fermentation method. Species such as Staphylococcus xylosus, S. lentus, S. saprophyticus, and Bacillus megaterium were found only in samples produced by method 1, while those of Staphylococcus piscifermentans, Bacillus mycoides, and Corynebacterium xerosis were found only in samples produced by method 2. Using specific primers, we detected several lactic acid bacteria (LAB), such as Lactobacillus, Pedicoccus, Lactcoccus, Streptococcus, and Leuconostoc species; the composition these bacteria in adjuevan samples varied according to the preparation method, but were not found to be dominant. We conclude that the molecular PCR-DGGE method can be used to differentiate fermentation methods by LAB profile analysis. A mixture of strains of S. xylosus, S. saprophyticus, S. cohnii, and S. piscifermentans were predominant, and LAB such as L. fermentum, L. lactis, L. pseudomesenteroides, L. raffinolactis, L. lactis subsp cremoris could be potentially beneficial for the specific flavor of each type of adjuevan to be selected as possible starter cultures for the development of a starter culture to improve adjuevan nutritional quality.     

An appraisal of Miscanthus x giganteus cultivation for fly ash revegetation and soil restoration

The objective of this study was to investigate the potential of Miscanthus x giganteus (MxG) for fly ash (FA) revegetation and soil restoration. To evaluate its growth ability on FA, plant development during pot experiments was compared to that obtain in a reference soil. Several physico-chemical parameters (pH, conductivity, dissolved organic carbon, ammonium, nitrite, nitrate, phosphate and potassium contents) and microbiological parameters (enumeration of total, ammonia oxidising and nitrite oxidising culturable bacteria and community diversity analysis) were investigated after plant growth. Plants demonstrated an adaptation to the FA substrate, with an average stem length and biomass production that was half of that observed in the reference soil. Lower chlorophyll contents were measured but the absence of necrosis symptom and hydration rates of aerial parts above 70% suggested physiological adaptation of plants to the FA substrate. Moreover, significant organic carbon inputs could be measured in FA leachates after 17 weeks of laboratory cultivation, which could be related to the establishment of MxG rhizosphere. Besides, the emergence of specific bacterial phylotype could be reported at the FA-root interface. Analysis of FA leachates in planted pots also showed marked decreases of nitrate but increases of nitrite contents, indicating a nitrogen cycle restart. Field trials confirmed the growth potential of MxG directly on FA, without any requirement of additional landfill soil amendment. Finally, we believe that fly ash revegetation with MxG could be an effective strategy for cost effective and long term FA disposal site rehabilitation.     

Phylogeny and nitrogen fixation potential of Bradyrhizobium species isolated from the legume cover crop Pueraria phaseoloides (Roxb.) Benth. in Eastern Cameroon

Pueraria is an herbaceous, perennial legume crop originating in Asia. Pueraria phaseoloides (Roxb.) Benth. (tropical kudzu) is frequently introduced into production systems and is used as green manure, a cover crop and a forage plant, making it important economically. We used P. phaseoloides as a trap crop to study and characterize soil rhizobia in Eastern Cameroon. Bacteria were isolated from fresh nodules collected from field-grown P. phaseoloides roots. The 16S-23S rRNA internal transcribed spacer (ITS) sequences from 30 bacterial isolates were amplified by polymerase chain reaction (PCR) and the reaction products were sequenced. Phylogenetic analysis revealed that all isolates were ascribed to the genus Bradyrhizobium and were grouped into three clusters of Bradyrhizobium sp. strains, one cluster of B. yuanmingense strains, and one cluster of B. elkanii strains. Acetylene reduction assay (ARA) results indicated that the B. yuanmingense strains had significantly higher nitrogen fixation potential and that they could be used as inoculants to enhance nitrogen fixation in Pueraria grown in Eastern Cameroon.     

Relevance of the positron emission tomography in the diagnosis of vascular graft infection with Coxiella burnetii

Coxiella burnetii, the causative agent of Q fever, may cause culture-negative vascular graft infections that can be diagnosed by serology and molecular biology. We present a case of vascular graft infection detected by positron emission tomography (PET) scanner. The presence of C. burnetii was confirmed by high antibody titers and positive polymerase chain reaction specific for C. burnetii. This report emphasizes the relevance of the PET scanner in the diagnosis of infection when used in association with Q fever serology and molecular biology for the etiological identification of C. burnetii.     

Q fever osteomyelitis: a case report and literature review

Q fever is a worldwide zoonosis caused by Coxiella burnetii. The clinical manifestations of Q fever include endocarditis, pneumonitis and hepatitis. Disease awareness and evolving diagnostic tests have enabled the recognition of unusual manifestations of Q fever. We report a case of Q fever osteomyelitis. A 51-year-old patient was admitted to hospital because of fever, leg weakness, and asthenia. His past medical history included surgery and a bone graft for the treatment of a giant cell tumor on the distal part of the femur. Blood and bone biopsy cultures were negative. Bone histological examination was consistent with a sub-acute or chronic inflammatory reaction that involved foci of epithelioid and gigantocellular infiltrates and necrosis. Serology testing revealed high antibody titers to C. burnetii antigens (phase I: IgG 3200; IgA 200; phase II: IgG 6400; IgA 400), which is indicative of chronic Q fever. The specific Polymerase Chain Reaction (PCR) of the abscess sample from the femoral region was positive for C. burnetii. The patient was treated for chronic Q fever with doxycycline and hydroxychloroquine for 18 months and recovered gradually without recurrence of pain or functional impairment. Q fever osteomyelitis is a rare and most likely underestimated disease. Epithelioid and gigantocellular granulomatous osteomyelitis in the context of culture-negative bone specimens should raise suspicion of Q fever. Serological tests, specific PCR and cell culture can provide evidence of a C. burnetii infection. Although bone diffusion may be a concern, the currently recommended treatment for Q fever was effective in this case.     

Cast production and NIR spectral signatures of Aporrectodea caliginosa fed soil with different amounts of half-decomposed Populus nigra litter

Sub-adult individuals of Aporrectodea caliginosa were incubated for 16 weeks under laboratory cultures in a soil treated with 0%, 10% or 50% of a Populus nigra half-decomposed leaves, respectively. Growth was maximum in the 50% organic matter treatment and cocoon production occurred. Average soil ingestion rates decreased from 1.56 g/g^?1 fresh weight of worm per day^?1 in control soil to 1.17 and 0.5 g, respectively, in treatments with 10% and 50% half-decomposed litter. Surface casts never comprised more than 10% of total cast production. Near-infrared spectrometry (NIRS)signatures of digested and non-ingested soil significantly differed and showed a rather constant effect of digestion, independent of the organic matter content (p?<?0.01). These results confirm the value of NIRS spectral signatures as indicators of the origin of soil aggregates and biological processes involved in soil aggregation.