New trends in instrumental design for surface plasmon resonance-based biosensors

Surface plasmon resonance (SPR)-based biosensing is one of the most advanced label free, real time detection technologies. Numerous research groups with divergent scientific backgrounds have investigated the application of SPR biosensors and studied the fundamental aspects of surface plasmon polaritons that led to new, related instrumentation. As a result, this field continues to be at the forefront of evolving sensing technology. This review emphasizes the new developments in the field of SPR-related instrumentation including optical platforms, chips design, nanoscale approach and new materials. The current tendencies in SPR-based biosensing are identified and the future direction of SPR biosensor technology is broadly discussed.     

Trace metals in marine,brackish and freshwater prawns (Crustacea,Decapoda) from northeast Algeria

The concentrations of the trace metals Zn, Cu, Fe, Cd and Pb were measured in four caridean decapods; Atyaephyra desmaresti, Palaemonetes varians, Parapenaeus longirostris and Aristeus antennatus, from freshwater , estuarine and marine habitats in northeast Algeria variably affected by anthropogenic metal contamination. The two coastal species (P. longirostris and A. antennatus) are a food source for the local population. Accumulated metal concentrations varied interspecifically, and intraspecifically between sites and between seasons, except in the case of Aristeus antennatus. The fresh and brackish water species (Atyaephyra desmaresti and Palaemonetes varians) accumulated more Cd and Pb than their marine counterparts. Results are discussed with respect to anthropogenic inputs and the environmental conditions of the regions studied.     

Trapping Proteins within Gold Nanoparticle Assemblies: Dynamically Tunable Hot-spots for Nanobiosensing

The combination of stimuli-responsive materials with localized surface plasmon resonance nanotransducers provides new leverages in hot spot-based nanosensing. We introduce a simple and effective biodetection method based on the hydro-responsive property of (3-aminopropyl)-triethoxysilane (APTES). Gold nanoparticles were adsorbed onto hydro-responsive APTES thin film. The exposure of the film surface to an aqueous solution results in opening inter-particle gaps, allowing analyte binding. A subsequent drying of the sensor surface closes the gap by bringing the nanoparticles to the initial position, thereby trapping the analyte in the most sensitive regions (electromagnetic hot spots). In this reversible configuration, the generation and tuning of the hot spots are independent from both the presence of the analyte and the functionalization of the nanoparticles, which yields highly resolved coupled plasmon bands and provide a general and flexible nanosensing modality. Furthermore, the intensity of the hot spots can be easily and reversibly tuned to obtain picomolar sensitivity.     

The impact of thyroid activity variations on some oxidizing-stress parameters in rats

The effect of the thyroid activity on the formation of lipid peroxidation and on liver and heart antioxidant enzyme activities was investigated in Wistar rats. Hypothyroidism and hyperthyroidism conditions were induced for five weeks by the administration of 0.05% benzythiouracile (BTU) and L-thyroxine sodium salt (0.0012%), in drinking water, respectively. No significant effect was observed on the rates of both lipid peroxidation and the vitamin E in hepatic and cardiac tissues of hypothyroidism rats compared to the controls, contrary to the hyperthyroidism rats, which expressed a pronounced increase. The increased glutathione peroxidase activity in rats suffering from hyperthyroidism was associated with a fall of the reduced glutathione in the homogenate and a marked increase in the glutathione reductase activity. An increase in superoxide dismutase and catalase activities was also recorded in hyperthyroidism. Our results explain the thyroid activity variation in relation to the lipid peroxidation and the tissular contents of the enzymatic and the non-enzymatic antioxidants. To conclude, our results show the occurrence of a state of oxidizing stress in relation to hyperthyroidism.     

Breeding ecology of the Little Bittern Ixobrychus minutus in northeast Algeria

Capsule This is the first study of the reproductive ecology of the Little Bittern Ixobrychus minutus in North Africa. During the study period, clutch size exhibited a sharp drop concurrent with a steady human encroachment and 30% habitat loss.

Aim To investigate the status, nest-site selection, breeding parameters, chick development and chick diet of Little Bittern in Algeria, under deteriorating habitat conditions

Methods Data were collected during surveys of all major Algerian wetlands (2002–08) and monitoring of breeding at Boussedra, a freshwater marsh in northeast Algeria, during the years 2005 and 2008.

Results Egg-laying spanned the period of 10 May to 30 June with one recorded case of a double brood in early July (n = 30). The mean clutch size in 2005 was 6.2?±?0.4 sd eggs per nest (n = 6 clutches), which was significantly higher than that of 2008, which amounted to 4.3?±?0.5 sd eggs per nest (n = 6 clutches), and this decline was associated with increased disturbance and loss of habitat. Overall, clutches suffered from a low rate of predation (17.6%) and displayed a high hatching rate (85.7%).

Conclusion Breeding parameters of the Little Bittern in North Africa are similar to elsewhere in Europe.     

Patterns of resource partitioning by nesting herons and ibis: How are odonata exploited?

Herons and ibis are colonially nesting waders which, owing to their number, mobility and trophic role as top predators, play a key role in aquatic ecosystems. They are also good biological models to investigate interspecific competition between sympatric species and predation; two processes which structure ecological communities. Odonata are also numerous, diverse, mobile and can play an important role in aquatic ecosystems by serving as prey for herons and ibis. A relationship between prey size and bird predator has been observed in Numidia wetlands (NE Algeria) after analyzing food boluses regurgitated by six species of birds (Purple Heron, Black-crowned Night Heron, Glossy Ibis, Little Egret, Squacco Heron and Cattle Egret) during the breeding period, which also shows a temporal gradient for the six species. Both the Levins index and preliminary multivariate analysis of the Odonata as prey fed to nestling herons and ibis, indicated a high degree of resource overlap. However, a distinction of prey based on taxonomy (suborder and family) and developmental stage (larvae or adults) reveals a clear size dichotomy with large-sized predators (Purple Heron, Black-crowned Night Heron and Glossy Ibis) preying on large preys like Aeshnids and Libellulids and small-sized predators feeding mainly on small prey like Zygoptera. Overall, the resource utilization suggests a pattern of resource segregation by coexisting nesting herons and ibis based on the timing of reproduction, prey types, prey size and foraging microhabitats.     

Cold plasma functionalized TeraHertz BioMEMS for enzyme reaction analysis

In this paper, we describe the development, functionalization and functionality testing of a TeraHertz (THz) Bio-MicroElectroMechanical System (BioMEMS) dedicated to enzyme reaction analysis. The microdevice was fabricated by mixing clean room microfabrication with cold plasma deposition. The first is used to build the microfluidic circuits and the THz sensor, while the later serves for the polymerization of allylamine using a homemade glow discharge plasma reactor for a subsequent immobilization of enzymatic biocatalysts. Thermal stability of the deposited plasma polymer has been investigated by infrared spectroscopy. Fluorescent detection confirmed the efficiency of the immobilization and the enzyme hydrolysis into the BioMEMS microchannels. For the first time, the progression of the hydrolysis reaction over time was monitored by the THz sensor connected to a vectorial network analyzer. Preliminary results showed that sub-THz transmission measurements are able to discriminate different solid films, various aqueous media and exhibit specific transmission behavior for the enzyme hydrolysis reaction in the spectral range 0.06–0.11 THz.     

The capacity of glutathione reductase in cell protection from the toxic effect of heated oils

This empirical study tries to focus on the evidence that the wrong use of oil in food cooking leads to health problems. High temperatures associated with the repeated use of the same oil lead to the breakdown of some fatty acids, forming numerous toxic polymer compounds and peroxides. The obtained data have showed that the ratios of polymer compounds reached 11.3% in oil heated continuously for 10 h at 220 degrees C, and 37.8% in frying oil (FO). Moreover, the polar compound ratios reached 25.6% and 47.6% in continuously heated oil (CHO) and FO, respectively. However, the peroxide concentrations were 157.1 and 133.6 mM/kg in CHOs and FOs, respectively. The observed results have allowed the study of the role of the glutathione redox system in the detoxification and elimination of different toxic peroxides resulting from heated oils. On a diet of 10% of CHO and FO, a significant increase in glutathione peroxidase (GPx) and glutathione reductase (GR) activities appears. This combined relationship between the decreased glutathione content and the increased GPx and GR activities in rats fed on CHO and FO confirms the participation of the glutathione redox system in the detoxifying reactions of continuously accumulated peroxides.