An exploration of the role of Sertoli cells on fetal testis development using cell ablation strategy

Sertoli cells (SCs) are presumed to be the center of testis differentiation because they provide both structural support and biological regulation for spermatogenesis. Previous studies suggest that SCs control germ cell (GC) count and Leydig cell (LC) development in mouse testes. However, the regulatory role of SCs on peritubular myoid (PTM) cell fate in fetal testis has not been clearly reported. Here, we employed Amh‐Cre; diphtheria toxin fragment A (DTA) mouse model to selectively ablate SCs from embryonic day (E) 14.5. Results found that SC ablation in the fetal stage caused the disruption of testis cords and the massive loss of GCs. Furthermore, the number of α‐smooth muscle actin‐labeled PTM cells was gradually decreased from E14.5 and almost lost at E18.5 in SC ablation testis. Interestingly, some Ki67 and 3β‐HSD double‐positive fetal LCs could be observed in Amh‐Cre; DTA testes at E16.5 and E18.5. Consistent with this phenomenon, the messenger RNA levels of Hsd3b1, Cyp11a1, Lhr, Star and the protein levels of 3β‐HSD and P450Scc were significantly elevated by SC ablation. SC ablation appears to induce ectopic proliferation of fetal LCs although the total LC number appeared reduced. Together, these findings bring us a better understanding of SCs’ central role in fetal testis development.     

超连续谱激光可见谱段致人眼眩目效应研究

本文采用超连续谱激光光源滤除其红外部分仅输出可见谱段部分,在不超过国家安全标准允许的最大辐照量条件下,以正入射方式照射人眼后,记录并分析在明、暗适应条件下中心极限视力恢复时间、中心近极限视力恢复时间和视觉后像持续时间,明确超连续谱激光可见谱段对人眼的眩目效果。明适应下激光照射0.1 s导致人眼中心极限视力恢复时间为31~119 s,中心近极限视力恢复时间为19~76 s;暗适应下激光照射0.1 s导致人眼中心极限视力恢复时间为26~223 s,中心近极限视力恢复时间为13~123 s;明、暗适应下导致人眼眩目效应的最小功率密度值分别为0.055 mW/cm^2和0.005 mW/cm^2。结果表明,超连续谱激光可见谱段对人眼有良好的眩目效果,可导致数十秒至数百秒的中心视力下降,随着照射功率密度增高,眩目效应增强,显示出较好的量效关系,且相同功率密度时暗适应下人眼的眩目效果优于明适应。该研究探究了明、暗适应条件下超连续谱激光对人眼眩目效应,明确了超连续谱激光与人眼眩目的量效关系。     

Insight into the bovine milk peptide LPcin‐YK3 selection in the proteolytic system of Lactobacillus species

Antimicrobial peptides are class of small, positively charged peptides known for their broad‐spectrum antimicrobial activity. Antimicrobial activities for most antimicrobial peptides have largely remained elusive, particularly in the lactic acid bacteria. However, recently our investigation using LPcin‐YK3, an antimicrobial peptide from bovine milk, suggests that in vitro antimicrobial activity was reduced over 100‐fold compared with pathogenic bacteria. Additionally, for the structural study of how antimicrobial peptide undergoes its reaction at the proteolytic pathway of lactic acid bacteria based on degradation assay and propidium iodide staining, we performed molecular docking for interaction between oligopeptide‐binding protein A and LPcin‐YK3 peptide. Given that degradation related to the LPcin‐YK3 peptide in lactic acid bacteria proteolytic system, the inhibitory inactivity of LPcin‐YK3 against beneficial lactic acid bacteria strains may be one of the primary pharmacological properties of recombinant peptide discovered in bovine milk. These results provide structural and functional insights into the proteolytic mechanism and possibility as a putative substrate of oligopeptide‐binding protein A in respect of LPcin‐YK3 peptide.     

A Comparison of Protein and mRNA Expression during Development of the Soil Dwelling Prokaryote (S. coelicolor)

In this paper, correlation analysis of protein and mRNA levels in the soil dwelling bacteria Streptomyces coelicolor (S. coelicolor M145) is presented during development of the population as it grew in liquid medium using three biological and two technical replicates, measured during exponential growth, and its entry into the stationary phase. The proteome synthesis time series are compared with the gene expression time series measured previously under identical experimental conditions. Results reveal that about one third of protein/mRNA synthesis profiles are well correlated while another third are correlated negatively. Functional analysis of the highly correlated groups is presented. Based on numerical simulation, the negative correlation between protein and mRNA is shown to be caused by the difference between the rate of translation and protein degradation.     

The effect of intrauterine inflammation on mTOR signaling in mouse fetal brain

Fetuses exposed to an inflammatory environment are predisposed to long‐term adverse neurological outcomes. However, the mechanism by which intrauterine inflammation (IUI) is responsible for abnormal fetal brain development is not fully understood. The mechanistic target of rapamycin (mTOR) signaling pathway is closely associated with fetal brain development. We hypothesized that mTOR signaling might be involved in fetal brain injury and malformation when fetuses are exposed to the IUI environment. A well‐established IUI model was utilized by intrauterine injection of lipopolysaccharide (LPS) to explore the effect of IUI on mTOR signaling in mouse fetal brains. We found that microglia activation in LPS fetal brains was increased, as demonstrated by elevated Iba‐1 protein level and immunofluorescence density. LPS fetal brains also showed reduced neuronal cell counts, decreased cell proliferation demonstrated by low Ki67‐positive density, and elevated neuron apoptosis evidenced by high expression of cleaved Caspase 3. Furthermore, we found that mTOR signaling in LPS fetal brains was elevated at 2 hr after LPS treatment, declined at 6 hr and showed overall inhibition at 24 hr. In summary, our study revealed that LPS‐induced IUI leads to increased activation of microglia cells, neuronal damage, and dynamic alterations in mTOR signaling in the mouse fetal brain. Our findings indicate that abnormal changes in mTOR signaling may underlie the development of future neurological complications in offspring exposed to prenatal IUI.     

Four cypermethrin isomers induced stereoselective metabolism in H295R cells

Cypermethrin (CP) is widely used for controlling agricultural and indoor vermin. Previous studies have reported the stereoselective difference of CP in biological activities. However, little is known about their potential mechanisms between metabolic phenotypes and endocrine-disrupting effects. Herein, nuclear magnetic resonance (NMR)-based metabolomics combining metabolite identification and pathway analysis were applied to evaluate the stereoselective metabolic cdisorders induced by CP isomers in human adrenocortical carcinoma cells (H295R) culture medium. Then, gene expression levels related to disturbed metabolic pathways were assessed to verify according to metabolic phenotypes. Metabolomics profiles showed that [(S)-cyano(3-phenoxyphenyl)methyl](1R,3R)-3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropane-1-carboxylate [(1R,3R,αS)-CP] induced the most significant changes in metabolic phenotypes than did the other stereoisomers. There are 10 differential metabolites (isoleucine, valine, leucine, ethanol, alanine, acetate, aspartate, arginine, lactate, and glucose) as well as two significantly disturbed pathways, including “pyruvate metabolism” and “alanine, aspartate, and glutamate metabolism,” that were confirmed in H295R cells culture medium of (1R,3R,αS)-CP compared with other stereoisomers. Polymerase chain reaction (PCR) array also confirmed the results of metabolomics. Our results can help to understand the potential mechanisms between the isomer selectivity in metabolic phenotypes and endocrine-disrupting effects. Data provided here not only lend authenticity to the cautions issued by the scientists and researchers but also offer a solution for the balance between environment and political regulations.     

Land-cover changes and distribution of wetland species in small valley habitats that developed in a Late Pleistocene middle terrace region

Wetlands Ecology and Management - Small valley topology on terraced uplands is a unique groundwater-dependent ecosystem in East Asia. Traditionally, this characteristic valley topology has been...     

Xylosandrus germanus in Central Europe: Spread into and within the Czech Republic

Invasive organisms represent great threats to ecosystems and great challenges to forest management. In Europe, the black timber bark beetle (Xylosandrus germanus) is an invasive secondary pest that mostly attacks the logs of felled trees. We showed the invasion history for Europe and using many local surveys, we summarize the current distribution and other available information on X. germanus in the Czech Republic. We report that this species is distributed from the lowlands to the mountains in the Czech Republic; it is widespread in the eastern half of the country, where it is more abundant in the warmer south and southeast areas than in the cooler areas. Most (78%) of the known localities are at elevation below 400 m a.s.l. Although an ice storm greatly increased X. germanus abundance near the border with Austria, its high abundance did not result in damage to standing trees. Presence of X. germanus in the Czech Republic for over 10 years has not led to heavy tree infestation.