Effect of Gradually Decreasing Photoperiod on Immune Function in Siberian Hamsters

Animals usually use photoperiod as an important environmental cue to time the year. In terms of the winter immunocompetence enhancement hypothesis, animals in the non-tropical zone would actively enhance their immune function to decrease the negative influence of stressors such as low temperature and food shortage in winter. In the present study, we mimicked the transition from summer to winter by decreasing photoperiod gradually and examined the variations of immune repsonses in Siberian hamsters (Phodopus sungorus)  to test this hypothesis. Twenty two female adult hamsters were randomly divided into the control (12h light: 12h dark, Control, n=11) and the gradually decreasing photoperiod group (Experiment, n=11). In the experiment group, day length was decreased from 12 h: 12 h light-dark cycle to 8 h: 16 h light-dark cycle at the pace of half an hour per week. We found that gradually decreasing photoperiod had no effect on body composition (wet carcass mass, subcutaneous, retroperitoneal, mesenteric and total body fat mass) and the masses of the organs detected such as brain, heart, liver and so on in hamsters. Similarly, immunological parameters including immune organs (thymus and spleen), white blood cells and serum bacteria killing capacity indicative of innate immunity were also not influenced by gradually decreasing photoperiod, which did not support the winter immunocompetence enhancement hypothesis. However, gradually decreasing photoperiod increased phytohaemagglutinin response post-24h of PHA challenge, which supported this hypothesis. There was no correlation between cellular, innate immunity and body fat mass, suggesting that body fat was not the reasons of the changes of cellular immunity. In summary, distinct components of immune system respond to gradually decreasing photoperiod differently in Siberian hamsters

Porous Para-aminobenzoic Acid Membrane Prepared by Electrochemical Method and Its Application in Voltammetric Determination of Dopamine

In this paper, we prepared poly para aminobenzoic acid (PABA) membrane on a glassy carbon electrode (GCE) using cyclic voltammetry(CV) following electrochemically degrading to form a porous PABA (PPABA) membrane. The PPABA membrane was characterized using CV technique, scanning electron microscope (SEM) measurements. The PPABA membrane could improve sensitivity of dopamine (DA) and inhibit ascorbic acid (AA) and uric acid (UA) electrochemical oxidation. The PPABA/GCE-based electrohemical sensor displayed a good linear ranges from 0 μM to 30 μM DA with a low detection limits of 1.6 μM DA (S/N=3) in voltammetry measurement. The proposed sensor has the advantages of being simple, reproducible and stable and can be used as a new sensitive electrochemical biosensor for the detection of DA

Porous Para-aminobenzoic Acid Membrane Prepared by Electrochemical Method and Its Application in Voltammetric Determination of Dopamine

In this paper, we prepared poly para aminobenzoic acid (PABA) membrane on a glassy carbon electrode (GCE) using cyclic voltammetry(CV) following electrochemically degrading to form a porous PABA (PPABA) membrane. The PPABA membrane was characterized using CV technique, scanning electron microscope (SEM) measurements. The PPABA membrane could improve sensitivity of dopamine (DA) and inhibit ascorbic acid (AA) and uric acid (UA) electrochemical oxidation. The PPABA/GCE-based electrohemical sensor displayed a good linear ranges from 0 μM to 30 μM DA with a low detection limits of 1.6 μM DA (S/N=3) in voltammetry measurement. The proposed sensor has the advantages of being simple, reproducible and stable and can be used as a new sensitive electrochemical biosensor for the detection of DA