Ras promotes germline stem cell division in Drosophila ovaries.

The Ras family genes are proto-oncogenes that are highly conserved from Drosophila to humans. In Drosophila, RasV12 is a constitutively activated form of the Ras oncoprotein, and its function in cell-cycle progression is context dependent. However, how it influences the cell cycle of female germline stem cells (GSCs) still remains unknown. Using both wild-type GSCs and bam mutant GSC-like cells as model systems, here we determined that RasV12 overexpression promotes GSC division, not growth, opposite to that in somatic wing disc cells. Ras performs this function through activating the mitogen-activated protein kinase (MAPK) signaling. This signaling is activated specifically in the M phase of mitotic germ cells, including both wild-type GSCs and bam mutant GSC-like cells. Furthermore, RasV12 overexpression triggers polyploid nurse cells to die through inducing mitotic stress. Given the similarities between Drosophila and mammalian GSCs, we propose that the Ras/MAPK signaling also promotes mammalian GSC division.

Genetic circuitry controlling Drosophila female germline overgrowth.

Germ cells mutant for bam or bgcn are locked in a germline stem cell (GSC)-like state, leading to tumor-like overgrowth in Drosophila ovaries. Our previous studies have demonstrated that germline overgrowth in bam mutants can be suppressed by defects in the miRNA pathway but enhanced by a null mutation in hippo. However, the genetic epistasis between the miRNA and Hippo pathways still remains unknown. Here, we determined that the miRNA pathway acts downstream of the Hippo pathway in regulating this process. Germ cells mutant for bam or bgcn and defective in both pathways divide very slowly, phenocopying those defective only in the miRNA pathway. In addition, we found that Yki, a key oncoprotein in the Hippo pathway, promotes the growth of both wild-type germ cells and bam mutant GSC-like cells. Like wild-type GSCs, bam mutant GSC-like cells predominantly stay in the G2 phase. Remarkably, many of those defective in the miRNA pathway are arrested before entering this phase. Furthermore, our studies identified bantam as a critical miRNA promoting germline overgrowth in bam or bgcn mutants. Taken together, these findings establish a genetic circuitry controlling Drosophila female germline overgrowth.

Steel Slag Accelerated Carbonation Curing for High-Carbonation Precast Concrete Development.

Steel slag as an alkaline industrial solid waste, possesses the inherent capacity to engage in carbonation reactions with carbon dioxide (CO2). Capitalizing on this property, the current research undertakes a systematic investigation into the fabrication of high-carbonation precast concrete (HCPC). This is achieved by substituting a portion of the cementitious materials with steel slag during the carbonation curing process. The study examines the influence of varying water-binder ratios, silica fume dosages, steel slag dosages, and sand content on the compressive strength of HCPC. Findings indicate that adjusting the water-binder ratio to 0.18, adding 8% silica fume, and a sand volume ratio of 40% can significantly enhance the compressive strength of HCPC, which can reach up to 104.9 MPa. Additionally, the robust frost resistance of HCPC is substantiated by appearance damage analysis, mass loss rate, and compressive strength loss rate, after 50 freeze-thaw cycles the mass loss, and the compressive strength loss rate can meet the specification requirements. The study also corroborates the high-temperature stability of HCPC. This study optimized the preparation of HCPC and provided a feasibility for its application in precast concrete.

A preliminary study on placental damage associated to experimental neosporosis in BALB/c mice.

Neospora caninum is a protozoan parasite which can infect a range of animals, including dogs, cattle, and sheep. Bovine neosporosis, which mainly causes abortion in cattle, results in substantial economic losses worldwide. To study the effects of N. caninum infection on the placenta, a pregnant mouse model for N. caninum infection was established. The litter size (8.6 ± 1.5) and the number of live pups (6.4 ± 1.8) of infected dams were significantly lower compared with those of non-infected dams. Trophoblast cell shrinkage and a large number of apoptosomes were detected in the placentas of the infected group. The parasite load in the placental tissue was significantly higher with time after infection. Likewise, apoptosis of placental trophoblast cells significantly increased with time after infection. Among the 66 apoptotic genes detected in this study, eight genes, including Bcl-2, were significantly differentially expressed by about > tenfold in infected and uninfected mice. The expression of BAX and tumor necrosis factor-alpha (TNF-α) was upregulated in the placental cells of the infected mice, whereas the expression of BCL-2 was downregulated. Enzyme-linked immunosorbent assays (ELISAs) showed that apoptotic protease caspase-3 level was significantly increased in placental cell suspension, and insulin-like growth factor (IGF)-2 level was significantly reduced. Acetylcholine (ACH) and placental prolactin (PL) levels were initially decreased but eventually increased. In summary, infection of mice with N. caninum caused apoptotic damage to the placental tissues, cells, and genes and affected the normal physiological functions of placenta, which may largely explain the adverse pregnancy outcomes caused by N. caninum infection in mice.

Carbonation Curing on Magnetically Separated Steel Slag for the Preparation of Artificial Reefs.

Magnetic separation is an effective method to recover iron from steel slag. However, the ultra-fine tailings generated from steel slag become a new issue for utilization. The dry separation processes generates steel slag powder, which has hydration activity and can be used as cement filler. However, wet separation processes produce steel slag mud, which has lost its hydration activity and is no longer suitable to be used as a cement filler. This study investigates the potential of magnetically separated steel slag for carbonation curing and the potential use of the carbonated products as an artificial reef. Steel slag powder and steel slag mud were moulded, carbonation-cured and seawater-cured. Various testing methods were used to characterize the macro and micro properties of the materials. The results obtained show that carbonation and hydration collaborated during the carbonation curing process of steel slag powder, while only carbonation happened during the carbonation curing process of steel slag mud. The seawater-curing process of carbonated steel slag powder compact had three stages: C-S-H gel formation, C-S-H gel decomposition and equilibrium, which were in correspondence to the compressive strength of compact increasing, decreasing and unchanged. However, the seawater-curing process of carbonated steel slag mud compact suffered three stages: C-S-H gel decomposition, calcite transfer to vaterite and equilibrium, which made the compressive strength of compact decreased, increased and unchanged. Carbonated steel slags tailings after magnetic separation underwent their lowest compressive strength when seawater-cured for 7 days. The amount of CaO in the carbonation active minerals in the steel slag determined the carbonation consolidation ability of steel slag and durability of the carbonated steel slag compacts. This paper provides a reference for preparation of artificial reefs and marine coagulation materials by the carbonation curing of steel slag.

Establishment of a model of Neospora caninum infection in pregnant mice.

The aim of this study was to establish an animal model of Neospora caninum infection in pregnant BALB/c mice infected with different doses of N. caninum tachyzoites. After infection, the female BALB/c mice were housed with male BALB/c mice. The aim of this study was to observe clinical signs and pathological changes, detect Nc5 gene expression in the main organs, and measure the wet weight and coefficient of the placenta of the pregnant mice. In addition, the level of cytokines and placental hormones in the serum was measured in pregnant mice. Our results showed that the optimal dose of the mice in the infected model was 105 tachyzoites. The infected pregnant mice presented with various clinical signs, including depression, ataxia, and variable mortality. Pathological observations of the brain, liver, and spleen in the mice exhibited hyperemia, bleeding, and swelling. Moreover, N. caninum tissue cysts or tachyzoites were observed in the brain, liver, and spleen tissues by hematoxylin-eosin (HE). The Nc5 gene was detected in the brain, liver, spleen, and placental tissues of the mice. With the increase in infection days, the weight of the placenta in the model mice increased, and the placenta ratio decreased gradually. Compared with the control group, the placenta weight and placental ratio were significantly different (P < 0.05). Furthermore, the levels of the placental hormones, corticotropin-releasing hormone (CRH), chorionic gonadotropin (CG), prolactin (PRL), and estriol (E3), and cytokines IFN-γ, IL-4, and TGF-ß were differentially expressed between the model and the control group (P < 0.05 or P < 0.01), which indicated that infection with N. caninum caused an imbalance in the regulatory function of the placental hormones and cytokines in pregnant mice. A pregnant mouse model of N. caninum infection was successfully established in this study, providing a foundation for the study of the pathogenic mechanisms of N. caninum.

Autophagy Promotes Tumor-like Stem Cell Niche Occupancy.

Adult stem cells usually reside in specialized niche microenvironments. Accumulating evidence indicates that competitive niche occupancy favors stem cells with oncogenic mutations, also known as tumor-like stem cells. However, the mechanisms that regulate tumor-like stem cell niche occupancy are largely unknown. Here, we use Drosophila ovarian germline stem cells as a model and use bam mutant cells as tumor-like stem cells. Interestingly, we find that autophagy is low in wild-type stem cells but elevated in bam mutant stem cells. Significantly, autophagy is required for niche occupancy by bam mutant stem cells. Although loss of either atg6 or Fip200 alone in stem cells does not impact their competitiveness, loss of these conserved regulators of autophagy decreases bam mutant stem cell niche occupancy. In addition, starvation enhances the competition of bam mutant stem cells for niche occupancy in an autophagy-dependent manner. Of note, loss of autophagy slows the cell cycle of bam mutant stem cells and does not influence stem cell death. In contrast to canonical epithelial cell competition, loss of regulators of tissue growth, either the insulin receptor or cyclin-dependent kinase 2 function, influences the competition of bam mutant stem cells for niche occupancy. Additionally, autophagy promotes the tumor-like growth of bam mutant ovaries. Autophagy is known to be induced in a wide variety of tumors. Therefore, these results suggest that specifically targeting autophagy in tumor-like stem cells has potential as a therapeutic strategy.

Germline Proliferation Is Regulated by Somatic Endocytic Genes via JNK and BMP Signaling in Drosophila.

Signals derived from the microenvironment contribute greatly to tumorigenesis . The underlying mechanism requires thorough investigation. Here, we use Drosophila testis as a model system to address this question, taking the advantage of the ease to distinguish germline and somatic cells and to track the cell numbers. In an EMS mutagenesis screen, we identified Rab5, a key factor in endocytosis, for its nonautonomous role in germline proliferation. The disruption of Rab5 in somatic cyst cells, which escort the development of germline lineage, induced the overproliferation of underdifferentiated but genetically wild-type germ cells. We demonstrated that this nonautonomous effect was mediated by the transcriptional activation of Dpp [the fly homolog of bone morphogenetic protein (BMP)] by examining the Dpp-reporter expression and knocking down Dpp to block germline overgrowth. Consistently, the protein levels of Bam, the germline prodifferentiation factor normally accumulated in the absence of BMP/Dpp signaling, decreased in the overproliferating germ cells. Further, we discovered that the JNK signaling pathway operated between Rab5 and Dpp, because simultaneously inhibiting the JNK pathway and Rab5 in cyst cells prevented both dpp transcription and germline tumor growth. Additionally, we found that multiple endocytic genes, such as avl, TSG101, Vps25, or Cdc42, were required in the somatic cyst cells to restrict germline amplification. These findings indicate that when the endocytic state of the surrounding cells is impaired, genetically wild-type germ cells overgrow. This nonautonomous model of tumorigenesis provides a simple system to dissect the relation between tumor and its niche.

Three RNA binding proteins form a complex to promote differentiation of germline stem cell lineage in Drosophila.

In regenerative tissues, one of the strategies to protect stem cells from genetic aberrations, potentially caused by frequent cell division, is to transiently expand the stem cell daughters before further differentiation. However, failure to exit the transit amplification may lead to overgrowth, and the molecular mechanism governing this regulation remains vague. In a Drosophila mutagenesis screen for factors involved in the regulation of germline stem cell (GSC) lineage, we isolated a mutation in the gene CG32364, which encodes a putative RNA-binding protein (RBP) and is designated as tumorous testis (tut). In tut mutant, spermatogonia fail to differentiate and over-amplify, a phenotype similar to that in mei-P26 mutant. Mei-P26 is a TRIM-NHL tumor suppressor homolog required for the differentiation of GSC lineage. We found that Tut binds preferentially a long isoform of mei-P26 3'UTR, and is essential for the translational repression of mei-P26 reporter. Bam and Bgcn are both RBPs that have also been shown to repress mei-P26 expression. Our genetic analyses indicate that tut, bam, or bgcn is required to repress mei-P26 and to promote the differentiation of GSCs. Biochemically, we demonstrate that Tut, Bam, and Bgcn can form a physical complex in which Bam holds Tut on its N-terminus and Bgcn on its C-terminus. Our in vivo and in vitro evidence illustrate that Tut acts with Bam, Bgcn to accurately coordinate proliferation and differentiation in Drosophila germline stem cell lineage.

Arterial chemotherapy and conformal radiation abolish malignant biliary obstruction.

Malignant biliary obstruction has been a challenge to clinical practitioners, especially when it is serious and complete. Chemotherapy or radiation alone is often unsuccessful. In this study, the authors report a 59-year-old patient with complete common bile duct obstruction caused by cholangiocarcinoma who was treated with arterial chemotherapy followed by 3-dimensional conformal radiation, which resulted in a good clinical outcome.

Genes of Hippo signaling network act unconventionally in the control of germline proliferation in Drosophila.

Hippo pathway and its related genes are required for growth control in various somatic tissues. The mutations of Hippo pathway components lead to tissue overgrowth cell-autonomously. Surprisingly, when we generated germline mutant clones of Hippo-network genes such as fat, expanded, hippo, salvador, and warts, we did not observe any overgrowth of these mutant cells. Consistently, overexpression of the progrowth gene yorkie, which is normally inhibited by Hippo signaling, did not lead to germline overgrowth either. In contrast to previous studies in epithelial tissues, these tumor suppressor genes are dispensable in germline cells for their proliferation control. Furthermore, we demonstrate that expanded functions nonautonomously to regulate spermatogonial proliferation. It appears that expanded acts from the somatic support cells surrounding the germline to restrict spermatogonial amplification.