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CUL4B ubiquitin ligase belongs to the cullin-RING ubiquitin ligase family. Although sharing many sequence and structural similarities,CUL4Bplays distinct roles in spermatogenesis from its homologous protein CUL4A. We previously reported that genetic ablation of Cul4a in mice led to male infertility because of aberrant meiotic progression. In the present study, we generated Cul4b germ cell-specific conditional knock-out (Cul4bVasa), as well as Cul4b global knock-out (Cul4bSox2) mouse, to investigate its roles in spermatogenesis. Germ cell-specific deletion of Cul4b led to male infertility, despite normal testicular morphology and comparable numbers of spermatozoa. Notably, significantly impaired sperm mobility caused by reduced mitochondrial activity and glycolysis level were observed in the majority of the mutant spermatozoa, manifested by low, if any, sperm ATP production. Furthermore, Cul4bVasa spermatozoa exhibited defective arrangement of axonemal microtubules and flagella outer dense fibers. Our mass spectrometry analysis identified INSL6 as a novel CUL4B substrate in male germ cells, evidenced by its direct polyubiquination and degradation by CUL4B E3 ligase. Nevertheless, Cul4b global knock-out males lost their germ cells in an age-dependent manner, implying failure of maintaining the spermatogonial stem cell niche in somatic cells. Taken together, our results show that CUL4B is indispensable to spermatogenesis, and it functions cell autonomously in male germ cells to ensure spermatozoa motility, whereas it functions non-cell-autonomously in somatic cells to maintain spermatogonial stemness. Thus, CUL4B links two distinct spermatogenetic processes to a single E3 ligase, highlighting the significance of ubiquitin modification during spermatogenesis. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we describe a wide-angle laser beam scanner and the rigorous result of the wide-angle laser beam scanner was obtained with the help of the vector refraction theory. Using the rigorous results, the distortion of the beam shape was discussed. The distortion of the beam shape is varying with the different relative angles of the double prisms. According to the conservation of the energy, the distribution of the laser intensity is changed too. [Copyright &y& Elsevier]

Abstract: In this paper, we present a simple technique to determine the coupling efficiency between a laser diode and a lensed-tip based on the ABCD transformation matrix method. We have compared our analysis technique to that of previous work and have found that the presented method is reliable in predicting the coupling efficiency of lensed-tip and has the advantage of simplicity of coupling efficiency calculation even by a pocket calculator. The results can be useful for designing coupling optics. [Copyright &y& Elsevier]

The polarizing properties of crossed-beam volume holographic gratings recorded by arbitrary polarization plane waves are considered, using the three-dimensional coupled wave theory. Simple analysis expressions for the amplitude profiles of the transmitted and diffracted waves are obtained. Detailed diffraction characteristics for the case of a finite plane wave of uniform amplitude distribution are presented. We discuss the influence of the polarized azimuths of the incident wave both at recording and at reconstruction on the amplitude profiles of the transmitted and diffracted waves. [ABSTRACT FROM AUTHOR]

A packagable free-space two-dimension optical crossbar network is described, and extended to three-dimension physical space. The interconnection between two neighbor switch stages is implemented only use a calcite slab and the bypass-exchange switch is also integrated in a LiNbO3 slice. So a basic building block only consists of a bypass-exchange switching array or matrix for processing and a calcite slab for optical interconnection. A packaged crossbar network can be constructed by cascading such building blocks. The signal-to-noise ratio and cascadability of the network are discussed. It is shown that the crossbar network is compact configuration, solid state, low energy loss, easy to cascade and assemble, and insensitive to disturbance. [ABSTRACT FROM AUTHOR]