Transcriptomic characterization of dying hair cells in the avian cochlea

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Production of biosurfactant on crude date syrup under saline conditions by entrapped cells of Natrialba sp. strain E21, an extremely halophilic bacterium isolated from a solar saltern (Ain Salah, Algeria)

A bacterial strain E21 was isolated from a sample of water collected in the salt lake located close to Ain Salah, Algeria. The analysis of 16S rRNA gene sequence had indicated that the strain had 93 % sequence similarity with the genus Natrialba sp. strain E21 (GenBank, FR750525.1) and was considered extremely halophilic. Production of biosurfactant by the strain E21 with free and entrapped cells was investigated using soluble starch in the saline conditions. Biosurfactant synthesis was followed by measuring the surface tension and emulsifying index 9 days under optimal conditions (40 °C, pH 7). Some diffusional limitations in alginate and agar beads affected the kinetics of biosurfactant production when compared to that obtained with free cells culture. The minimum values of surface tension were 27 and 30 mN m^?1 achieved after 9 days with free and immobilized cells, respectively, while the corresponding maximum E24 values were 65.3 and 62.3 %, respectively. The re-use of bacterial cells along with the limited cell losses provided by the immobilized system might lead to significant reduction of the biosurfactant production cost.     

Dynamics of infestation of tracers lambs by gastrointestinal helminths under a traditional management system in the North of Tunisia

The authors present a survey of gastrointestinal helminths of sheep on permanent pastures in the extreme north region of Tunisia (Mediterranean climate). Dynamic infestation of animals has been monitored by using batches of three tracer lambs introduced each two months during 2004 and 2005. These lambs were kept in the pens of veterinary school of Sidi Thabet (Tunisia) during three months and then necropsied. Faecal and blood samples were took from tracer lambs each two months during the whole period, and from animal flock only during 2004. The main helminth genera encountered were Trichostrongylus spp., Teladorsagia spp., Strongyloides papillosus and Anoplocephalidea; occasionaly were found Nematodirus, Oesophagostomum, Chabertia, Cooperia, Trichuris and Paramphistomum. The egg count of the ewes and lambs in the flock showed two peaks. For both ewes and lambs there is a gradual increase from January with a peak in May-June. This first peak is considered to be due to acquisition of infective larvae during the rainy and cold season, as evident from the worm burdens of tracer lambs. The second peak was exclusively observed in ewes during late autumn-early winter (November-December); it has two origins: infestation by third larvae stage and the periparturient rise. The worm burdens of tracer lambs showed that there was a gradual accumulation of nematodes from September- October, reaching a peak in March-April; a very low or naught infection is reported during the dry period (July-August). Infection by Anoplocephalidea was higher during the dry season. This study is primordial for a comprehensive control programme implementation against gastrointestinal helminths.     

Differential distribution of V-type H+-ATPase and Na+/K+-ATPase in the branchial chamber of the palaemonid shrimp Macrobrachium amazonicum

Increased fragility fracture risk with improper healing is a frequent and severe complication of insulin resistance (IR). The mechanisms impairing bone health in IR are still not fully appreciated, which gives importance to studies on bone pathologies in animal models of diabetes. Mice deficient in leptin signaling are widely used models of IR and its comorbidities. Leptin was first recognized as a hormone, regulating appetite and energy balance; however, recent studies have expanded its role showing that leptin is a link between insulin-dependent metabolism and bone homeostasis. In the light of these findings, it is intriguing to consider the role of leptin resistance in bone regeneration. In this study, we show that obese diabetic mice lacking leptin receptor (db/db) are deficient in postnatal regenerative osteogenesis. We apply an ectopic osteogenesis and a fracture healing model, both showing that db/db mice display compromised bone acquisition and regeneration capacity. The underlying mechanisms include delayed periosteal mesenchymatic osteogenesis, premature apoptosis of the cartilage callus and impaired microvascular invasion of the healing tissue. Our study supports the use of the db/db mouse as a model of IR associated bone-healing deficits and can aid further studies of mesenchymatic cell homing and differentiation, microvascular invasion, cartilage to bone transition and callus remodeling in diabetic fracture healing.     

Diesel Biodegradation Capacities and Biosurfactant Production in Saline-Alkaline Conditions by Delftia sp NL1, Isolated from an Algerian Oilfield

Abstract

In this study, a diesel oil-degrading bacterium was isolated from an oilfield water injection (water-bearing formations, 1,205?m depth) in Algeria. The bacterial strain, designated NL1, was cultivated on diesel oil as sole carbon and energy sources. Molecular analyses of the 16S rRNA gene sequence (KY397882) placed NL1 strain closely related to distinct cultivated species of the Delftia genus. Optimal diesel oil biodegradation by Delftia sp NL1 strain occurred at pH 11, 40?°C, 2?M NaCl and initial hydrocarbon concentration of 5% (v/v) as sole carbon source. GC-MS analyses evidenced that strain Delftia sp NL1 was able to degrade more than 66.76% of diesel oil within only 7?days. On the other hand, and in the same conditions, biosurfactant production by Delftia sp NL1 was also evaluated evidencing high emulsifying capacity (E₂₄ = 81%), ability to lower the surface tension of growing media (with the value of 25.7?mN m^?1), and production of glycolipids (8.7?g L^?1) as biosurfactants. This research presents indigenous strain Delftia sp NL1 for diesel degradation and synthesis of biosurfactant in extreme conditions. In this sense, strain NL1 is a good candidate for possible in situ oil recovery and in wastewater treatment in refineries and oil terminals in petroleum industry.     

Place des explorations isotopiques dans les otites externes nécrosantes

BackgroundThe necrotizing otitis externa (NOE) is potentially lethal which mainly occurs on the most among the elderly and diabetic. The aim of our study was to evaluate the contribution of isotopic explorations in diagnosis, staging and monitoring of the NOE.MethodsOur retrospective study was about 50 patients with a strong suspicion of NOE who benefited a bone and/or gallium scintigraphy.ResultsOur population was composed of 38 men and 12 women with mean age of 68 years. All patients were diabetic. The most common complaint was otalgia (98% of cases). The sensitivity of computed tomography (CT) which was performed in 84% of cases was 66.6% of cases. Bone scintigraphy (BS) was performed in all patients showing increased uptake in the temporal region in 90% of cases. An extension to surrounding structures was objectified in 26% of cases. Follow-up Ga 67 SPECT was performed in 56% of cases, demonstrated increased uptake at the temporal region in 43% of cases. The statistical study showed that only the presence of an extended tympanic lysis on CT was statistically significant to the positivity of BS (P = 0.036). No statistically significant correlation was found between all other CT abnormalities, clinical and biological signs and the positivity of bone scintigraphy.ConclusionIsotopic explorations were a great contribution in the management of the NOE. At the initial phase, the BS allowed to confirm very early an existence of osteomyelitis of the skull base. During the follow-up, the gallium-67 scan allowed the following of the evolution of infectious process.