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In the neurogenic niches of the adult hippocampus, new functional neurons are continuously generated throughout life, and generation of these neurons has been implicated in learning and memory. Astrocytes, as components of the neurogenic niches, are critical in the regulation of adult hippocampal neurogenesis (AHN). However, little is known about how astrocytes receive and respond to extrinsic cues to regulate AHN. By using a transgenic strategy to conditionally delete astrocytic CRHM1 in mice and AAV (adeno-associated virus)–mediated overexpression of astrocytic CHRM1 specifically in the hippocampal dentate gyrus, we systematically investigated the role of astrocytic CHRM1 in the regulation of AHN and the underlying mechanisms using the combined approaches of immunohistochemistry, retrovirus labeling, electrophysiology, primary astrocyte cultures, immunoblotting, and behavioral assays. We report that genetic ablation of CHRM1 in astrocytes led to defects in neural stem cell survival, neuronal differentiation, and maturation and integration of newborn neurons in the dentate gyrus. Astrocytic CHRM1-mediated modulation of AHN was mediated by BDNF (brain-derived neurotrophic factor) signaling. Furthermore, CHRM1 ablation in astrocytes impaired contextual fear memory. These impairments in both AHN and memory were rescued by overexpression of astrocytic CHRM1 in the dentate gyrus. Our findings reveal a critical role for astrocytes in mediating cholinergic regulation of AHN and memory through CHRM1. [ABSTRACT FROM AUTHOR]

Depression is a common but serious mental disorder and can be caused by the side effects of medications. Evidence from abundant clinical case reports and experimental animal models has revealed the association between the classic anti-acne drug 13-cis-retinoic acid (13-cis-RA) and depressive symptoms. However, direct experimental evidence of this mechanism and information on appropriate therapeutic rescue strategies are lacking. Herein, our data revealed that chronic administration of 13-cis-RA to adolescent mice induced depression-like behavior but not anxiety-like behavior. We next demonstrated that chronic 13-cis-RA application increased neural activity in the dentate gyrus (DG) using c-Fos immunostaining, which may be critically involved in some aspects of depression-like behavior. Therefore, we assessed electrophysiological functions by obtaining whole-cell patch-clamp recordings of dentate granule cells (DGCs), which revealed that chronic 13-cis-RA treatment shifted the excitatory-inhibitory balance toward excitation and increased intrinsic excitability. Furthermore, a pharmacogenetic approach was performed to repeatedly silence DGCs, and this manipulation could rescue depression-like behavior in chronically 13-cis-RA-treated mice, suggesting DGCs as a potential cellular target for the direct alleviation of 13-cis-RA-induced depression. [ABSTRACT FROM AUTHOR]

The separation of reproductive and non-reproductive roles based on caste differentiation is the most prominent characteristic of termites. However, little is known about the mechanism of male reproductive division that underlies caste differentiation. In the present study, testicular development and stage-specific apoptotic patterns were investigated and compared during spermatogenesis in reproductives, workers and soldiers of the termite Reticulitermes labralis . The results showed that male workers were divided into two types, the workers with spermatozoa (W S ) and the workers without spermatozoa (W N ). Spermatogenesis in W N and soldiers arrested at the spermatocyte stage. Moreover, there were significant differences in testicular size and spermatogenesis among the various castes. The mode of apoptosis in late instar W S was similar to the reproductives, as demonstrated by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL) analysis. First, the majority of apoptotic cells were spermatogonia, and the spermatogonia of both late instar W S and reproductives exhibited lower apoptotic rates compared with late instar W N and soldiers. Second, the spermatocytes and spermatids showed very little apoptosis in the late instar W S and reproductives, and no TUNEL signal was detected in any of the examined spermatozoa. Our findings suggest that the male workers undergo a basal developmental schema comprising two undifferentiated larval instars, followed by a bifurcated development into either (i) the sexual lineage, in which the workers are able to provide normal spermatozoa to queens, or (ii) the neuter lineage, in which the male workers lose reproductive options. The level of testicular development may explain the significant discrepancies in reproductive capacity among the reproductives, workers and soldiers and reveal the reproductive division in male workers. These differences are controlled by apoptosis during early spermatogenesis. [ABSTRACT FROM AUTHOR]

Herein, a novel Cd-based coordination polymer [Cd(HL)(4,4′-bipy)(H 2 O)] n (1) and a metal-organic framework {[Cd 3 (L) 2 (bip) 2 (H 2 O) 3 ]·5H 2 O} n (2) have been synthesized by employing semi-rigid tricarboxylic acid ligands (H 3 L) and different N -containing ligands under hydrothermal conditions. Single crystal X-ray analysis reveals that 1 presents a 4-connected 2D network structure with a Schläfli symbol of (44·62), 2 possesses a (3,4,4)-connected 3D framework with a Schläfli symbol of (4.82) 2 (42.82.102)(8.104.12). A series of fluorescence detection studies confirm that 1 present a highly and drastically selective response towards Co2+, Cr 2 O 7 2–, nitrobenzene and nitromethane, while 2 for Ag+, CrO 4 2– and nitrobenzene. The possible fluorescence quenching mechanisms are studied in detail, revealing that fluorescence quenching is related to weak interaction, competitive energy absorption and electron transfer. [Display omitted] Highly effective recognition and detection of metal ions, anions and organic small molecules from water have attracted remarkable attention for environmental safety. Herein, a novel Cd-based coordination polymer [Cd(HL)(4,4′-bipy)(H 2 O)] n (1) and a metal–organic framework {[Cd 3 (L) 2 (bip) 2 (H 2 O) 3 ]·5H 2 O} n (2) have been synthesized by employing a semi-rigid tricarboxylic acid ligand (H 3 L) and different N -containing ligands under hydrothermal conditions, where H 3 L = 3-[(1-carboxynaphthalen-2-yl)oxy] phthalic acid, 4,4′-bipy = 4,4′-bipyridine, bip = 1,4-di(pyridine-4-yl) benzene. Single crystal X-ray analysis reveals that 1 presents a 4-connected 2D network structure with a Schläfli symbol of (44·62),whilst 2 possesses a (3,4,4)-connected 3D framework with a Schläfli symbol of (4.82) 2 (42.82.102)(8.104.12). Furthermore, 1 and 2 have been characterized by elemental analyses, FT-IR, powder X-ray diffraction, thermogravimetric analyses, fluorescence and UV spectra, exhibiting good stability and excellent photoluminescence properties. 1 and 2 have been chosen as fluorescent probes to sense different target analytes, showing an obvious selective recognition response to Co2+, Ag+, Cr 2 O 7 2-, CrO 4 2-, nitrobenzene and nitromethane through luminescence quenching effects in aqueous solutions. The possible fluorescence quenching mechanisms are studied in detail, revealing that fluorescence quenching is mainly related to weak interactions, competitive energy absorption and electron transfer. [ABSTRACT FROM AUTHOR]