Expressions of melanopsins in telencephalon imply their function in synchronizing semilunar spawning rhythm in the mudskipper Boleophthalmus pectinirostris.

The mudskipper Boleophthalmus pectinirostris inhabits intertidal mudflats, exhibiting semilunar reproductive rhythms. To investigate whether melanopsin is possibly involved in the synchronization of the semilunar spawning rhythm in the female mudskipper, we first cloned all four melanopsin subtypes (opn4m1, opn4m3, opn4x1, opn4x2) in B. pectinirostris. Results from RTq-PCR showed that significantly higher transcription levels of all four melanopsin subtypes were observed in the eyes rather than other tissues. In brain, all four melanopsin subtypes were also detectable in different regions, including the telencephalon, in which the expression of melanopsin has not been reported in other teleosts. The transcription levels of opn4m3 and opn4x1 in the telencephalon exhibited a daily fluctuation pattern. When females entered the spawning season, opn4m1 and opn4x1 transcript levels increased significantly in the telencephalon. During the spawning season, the transcript levels of opn4m3 and opn4x1 in the telencephalon appeared to have a cyclic pattern associated with semilunar periodicity, exhibiting two cycles with a peak around the first or the last lunar quarters. Results from ISH showed that, opn4x1 mRNA was localized in the medial of dorsal telencephalic area, dorsal nucleus of ventral telencephalic area (Vd), ventral nucleus of ventral telencephalic area (Vv), anterior part of parvocellular preoptic nucleus, magnocellular part of the magnocellular preoptic nucleus (PMmc), habenular and ventral zone of hypothalamus. Intriguingly, gnrh3 mRNA was also located in Vd, Vv and PMmc. Taken together, our results suggested that melanopsins, e.g. opn4x1, expressed in the telencephalon might mediate semilunar spawning activity in the female mudskipper.

Cloning and expression of two hepcidin genes in the mudskipper (Boleophthalmus pectinirostris) provides insights into their roles in male reproductive immunity.

The mudskipper Boleophthalmus pectinirostris is a burrow-dwelling fish inhabiting intertidal mudflats. During the spawning season, in a spawning chamber located at the center of their burrow, a pair of male and female fish mate and fertilized eggs adheres onto the inner walls and ceiling with filamentous attachments. During 5 days of incubation, the fertilized eggs are kept clean and hatch with a very high hatching rate under the natural conditions filled with microorganisms. This suggests that the male and/or female reproductive tract may synthesize antimicrobial substances to offer protection against microorganisms that may be deleterious to fertility. To study the antimicrobial strategy of this fish in the spawning season, we first cloned the two hepcidin isoforms from B. pectinirostris, and designated them as Hepcidin-1 and Hepcidin-2 based on phylogenetic analyses. Both of these hepcidin isoforms were highly expressed in the liver, but only Hepcidin-1 showed significant change in response to iron overload. Interestingly, these two hepcidin isoforms were expressed in male reproductive tracts, i.e. the testes and seminal vesicles. The monthly expression pattern indicated that Hepcidin-1 transcript levels showed a peak point only in March (before spawning) in the seminal vesicle, while Hepcidin-2 transcript levels were correlated with male reproductive status and reached their highest level in May (the peak spawning period). Under experimental conditions, the expression of these two hepcidin isoforms showed no response to iron overload in the male gonad. However, after lipopolysaccharide injection, the Hepcidin-1 transcript level was significantly up-regulated in the testes and seminal vesicle 6 h post injection, while Hepcidin-2 transcript levels exhibited a clear time-course dependent upregulation pattern and reached the highest levels 24 h post injection. More interestingly, after injection with LHRH-A3, the expression of Hepcidin-2 was significantly up-regulated in both testes and seminal vesicle. Results from in situ hybridization showed that Hepcidin-2 was expressed in the Leydig cells of the testes and in the epithelium of the seminal vesicle. Taken together, the results from our study indicated that these two hepcidin isoforms in the mudskipper may have different functions: Hepcidin-1 may play a dual role in both iron metabolism regulation in the liver and a short antimicrobial response in male reproductive tracts, while Hepcidin-2 is more specialized in reproductive immunity in male reproductive tracts.

Adaptive Filter Design Using Type-2 Fuzzy Cerebellar Model Articulation Controller.

This paper aims to propose an efficient network and applies it as an adaptive filter for the signal processing problems. An adaptive filter is proposed using a novel interval type-2 fuzzy cerebellar model articulation controller (T2FCMAC). The T2FCMAC realizes an interval type-2 fuzzy logic system based on the structure of the CMAC. Due to the better ability of handling uncertainties, type-2 fuzzy sets can solve some complicated problems with outstanding effectiveness than type-1 fuzzy sets. In addition, the Lyapunov function is utilized to derive the conditions of the adaptive learning rates, so that the convergence of the filtering error can be guaranteed. In order to demonstrate the performance of the proposed adaptive T2FCMAC filter, it is tested in signal processing applications, including a nonlinear channel equalization system, a time-varying channel equalization system, and an adaptive noise cancellation system. The advantages of the proposed filter over the other adaptive filters are verified through simulations.

[Investigation on degradation of polypropylene/stabilizers composites irradiated by gamma rays].

The degradation behavior of polypropylene and polypropylene/stabilizer composites, caused by gamma radiation, was studied in the present work The stabilizers used were hindered phenol antioxidant and hindered amine light stabilizer. FTIR spectroscopy and DSC analysis were used to determine the structural variation induced by gamma radiation. It can be seen that the evolution of PP and composites PP/stabilizers on gamma irradiation is an increase in absorbance in the hydroxyl and carbonyl absorption regions. Carbonyl index calculated from FTIR spectra was used to characterize the rate of degradation. When the irradiation dose was small (<50 kGy), the degradation of pure polypropylene and polypropylene/stabilizers composites was not obvious; while the irradiation dose increased (> or =50 kGy), the carbonyl indexes of all the samples increased obviously, and the degradation degree of polypropylene/stabilizer composites was bigger than pure polypropylene. This result might be partially attributed to the molecular chain scission of hindered phenol and hindered amine under larger irradiation dose. The chain scission of stabilizers forms hydroperoxides and peroxide radicals, catalyzing the degradation of polypropylene. As the irradiation dose was small (<50 kGy), the crystallization temperatures of pure polypropylene and polypropylene/stabilizer composites all showed no remarkable changes; as the irradiation dose exceeded 50 kGy, the crystallization temperatures of pure polypropylene and polypropylene/stabilizer composites all decreased obviously. Correspondingly, the melting peaks of both pure polypropylene and polypropylene/stabilizer composites moved to lower temperature and split into two peaks with increasing the irradiation dose. The decrease of crystallization and melting temperatures might be attributed to the destruction of chemical structure and stereo-regularity of the molecular chain, due to the increasing of carbonyl and hydroxyl groups brought by the oxidation of polypropylene molecular chain. At the same irradiation dose (> or = 50 kGy), the crystallization and melting temperatures of polypropylene/stabilizer composites were lower than that of pure polypropylene. It indicates that the stabilizers accelerate the degradation of polypropylene. The results were accordant with the IR results.

[Investigation on photooxidative degradation of polypropylene/organomontmorillonite nanocomposites].

Photooxidation degradation of polypropylene (PP)/organomontmorillonite (OMMT) nanocomposites was studied under UV irradiation at wavelength 365 nm. The OMMT was dispersed homogeneously in the PP matrix. The structural variation induced by photooxidation was detected by FTIR spectroscopy. It can be seen that the evolution of PP and nanocomposites PP/OMMT on irradiation is an increase in absorbance in the hydroxyl and carbonyl absorption regions. Carbonyl index was used to characterize the rate of photooxidative degradation. At the early stage of irradiation (shorter than 11 hours), the rate of photooxidative degradation of PP/OMMT nanocomposites was much faster than that of pure PP. With the increase in the irradiation time, the rate of photooxidative degradation of PP/OMMT nanocomposites became slower than that of pure PP. On the other hand, the OMMT content can also influence the photooxidative degradation rate. The variation in the photooxidative degradation rate is proposed to originate from the competition between the light shielding effect and accelerating photo-oxidative degradation effect of organomontmorillonite. These two effects play roles in the photooxidation process of PP simultaneously. At the early stage of irradiation, the accelerating photooxidative degradation effect dominates. With the increase in the irradiation time, the active sites such as SiOH, --OH etc and transition metal ions (Fe2+, Fe3+ etc) in the OMMT which can accelerate photooxidation are gradually consumed, and then the light shielding effect may play the main role. The method of curve-fitting was used to characterize the influence of organomontmorillonite on the photooxidative degradation products. Compared with pure PP, the content of products of carboxylic acid and anhydride were found to increase, whereas that of ester decreases in PP/OMMT nanocomposites.