Mitochondrial genome of captive Alpine musk deer, Moschus chrysogaster (Moschidae), and phylogenetic analyses with its coordinal species.

Alpine musk deer, Moschus chrysogaster, a solitary, primitive ungulate inhabiting high elevation areas (3000-4500 m) is an endangered species facing threat of extinction globally due to excessive hunting for its musk. In this study, we determined the complete mitochondrial genome of M. chrysogaster, which was 16,354 bp in length, and revealed the same gene order and genomic organization as typical Moschidae mitochondrial DNA. Start codons in 13 protein-coding genes (PCGs) were all typical ATGs except ATA for ND2 and ND3 and ATT for ND5. Stop codons were all typical types except an incomplete stop codon T for COX3, ND2, ND3, and ND4. Secondary structures in 22 transfer RNA genes all showed typical cloverleaf except tRNA-Ser (AGY), in which the dihydrouridine arm formed a simple loop. No repeat units were found in the control region. The topology structure indicated that M. cupreus was primitive and located at the root of the Moschidae clade. Phylogenetic reconstruction placed M. chrysogaster as a distinct lineage, closely related to the branch of M. leucogaster, M. berezovskii (wild) and predicted a sister relationship with M. moschiferus, M. anhuiensis, and M. berezovskii (captive). However, we suggested that the genetic resources of M. chrysogaster_JQ608470 should be further investigated.

Next generation sequencing yields the complete mitogenome of captive forest musk deer, Moschus berezovskii (Ruminantia: Moschidae).

Moschus berezovskii is an endangered species, but its captive populations are valuable on musk secretions in traditional Chinese medicine and perfume manufacture. The mitogenome of M. berezovskii was 16,353 bp in size. Stop codons in 13 PCGs were all typical types except incomplete stop codon T for COX3, ND2 and ND4, and TA for ND3. No tandem repeat was found in control region. Phylogenetic analysis indicated that Moschidae has the closest relationship with Bovidae. We supported that M. berezovskii should be categorized into two subspecies, and suggested that the status of M. chrysogaster JQ608470 should be further investigated.

Differentiation of spermatogonial stem cell-like cells from murine testicular tissue into haploid male germ cells in vitro.

In vitro differentiation of spermatogonial stem cells (SSCs) promotes the understanding of the mechanism of spermatogenesis. The purpose of this study was to isolate spermatogonial stem cell-like cells from murine testicular tissue, which then were induced into haploid germ cells by retinoic acid (RA). The spermatogonial stem cell-like cells were purified and enriched by a two-step plating method based on different adherence velocities of SSCs and somatic cells. Cell colonies were present after culture in M1-medium for 3 days. Through alkaline phosphatase, RT-PCR and indirect immunofluorescence cell analysis, cell colonies were shown to be SSCs. Subsequently, cell colonies of SSCs were cultured in M2-medium containing RA for 2 days. Then the cell colonies of SSCs were again cultured in M1-medium for 6-8 days, RT-PCR and indirect immunofluorescence cell analysis were chosen to detect haploid male germ cells. It could be demonstrated that 10(-7) mol l(-1) of RA effectively induced the SSCs into haploid male germ cells in vitro.

Cryoprotective effects of low-density lipoproteins, trehalose and soybean lecithin on murine spermatogonial stem cells.

Spermatogonial stem cells (SSCs) have the ability to self-renew and offer a pathway for genetic engineering of the male germ line. Cryopreservation of SSCs has potential value for the treatment of male infertility, spermatogonial transplantation, and so on. In order to investigate the cryopreservation effects of different cryoprotectants on murine SSCs, 0.2 M of low-density lipoproteins (LDL), trehalose and soybean lecithin were added to the cryoprotective medium, respectively, and the murine SSCs were frozen at -80°C or -196°C. The results indicated that the optimal recovery rates of murine SSCs in the cryoprotective medium supplemented with LDL, trehalose and soybean lecithin were 92.53, 76.35 and 75.48% at -80°C, respectively. Compared with freezing at -196°C, the optimum temperature for improvement of recovery rates of frozen murine SSCs, cryopreservation in three different cryoprotectants at -80°C, were 17.11, 6.68 and 10.44% respectively. The recovery rates of murine SSCs in the cryoprotective medium supplemented with 0.2 M LDL were significantly higher than that of other cryoprotectants (P < 0.05). Moreover, the recovery rates were demonstrated to be greater at -80°C compared with at -196°C (P < 0.05). In conclusion, 0.2 M of LDL could significantly protect murine SSCs at -80°C. In the freezing-thawing process, LDL is responsible for the cryopreservation of murine SSCs because it can form a protective film at the surface of membranes. However, more research is needed to evaluate and understand the precise role of LDL during the freezing-thawing of SSCs.

Effects of GDNF and LIF on mouse spermatogonial stem cells proliferation in vitro.

Spermatogonial stem cells (SSCs) are the only type of cells that transmit genes to the subsequent generations. The proliferation, cultivation and identification of SSCs in vitro are critical to understanding of male infertility, genetic resources and conservation of endangered species. To investigate the effects of glial cell-derived neurotrophic factor (GDNF) and leukemia inhibitory factor (LIF) on the proliferation of mouse SSCs in vitro, supplement of GDNF and/or LIF were designed to culture SSCs. The testes of 6-8 d mouse were harvested and digested by two-step enzyme digestion method. The SSCs and Sertoli cells were separated by differential plating. Then the SSCs were identified by alkaline phosphatase staining, RT-PCR and indirect immunofluorescence cell analysis. The cellular proliferation capacity was measured by methyl thiazolyl tetrazolium assay. The results showed that addition of 20 and 40 ng/ml of GDNF could strongly promote growth of mouse SSCs (p < 0.05). There was no significant difference between LIF treatment groups and the control group in promoting proliferation of the mouse SSCs (p > 0.05). However, the combination of 20 ng/ml GDNF and 1,000 U/ml LIF could significantly enhance the invitro proliferation of mouse SSCs (p < 0.05), and the OD490 value was 0.696 at day 5 of culture when the density of SSCs was 5-10 × 10(4) cells/ml.