The development of mouse spinal cord in tissue culture

Summary Whole mouse embryos were grown in vitro from Theiler stage 12 (1 to 7 somites) to Theiler stages 15 and 16 (25 to 35 somites). This procedure gives experimental access to precisely staged embryos during the early period of neurogenesis. To follow the further development of neurons in vitro, fragments of spinal primordia were set up from these cultured embryos. In such cultures, the proliferation of precursor cells, the formation of postmitotic cells and, finally, the cytodifferentiation of neurons were observed. A preliminary account of this work was given at the Tissue Culture Association Meeting in 1977, and the Canadian Federation of Biological Societies Meeting in 1977 (1,2). This work was supported by Grant MT 4235 from the Medical Research Council of Canada.     

Antimetabolic activities of 2-fluoro-L-histidine.

2-Fluoro-L-Histidine inhibits protein synthesis in various cell cultures, as measured by ³H-leucine incorporation. This histidine analog also inhibits the cytopathogenicity of a number of RNA and DNA viruses in primary and continuous cell cultures; it blocks the transformation of normal mouse (MO) cells by murine sarcoma virus, and partially suppresses the release of murine leukemia virus by a continuously infected mouse cell line (JLSV5). In human skin fibroblasts, it reduces the interferon-inducing capacity of poly(I)·poly(C). Inhibition of cell protein synthesis may be the common cause of the various effects. 4-Fluoro-L-histidine is essentially inert in all of the test systems examined.     

Gene expression profile in immunologically injured liver cell of mice

To study the gene expression profiles between immunologically injured liver cell and normal liver cell of mice and to screen on a large scale the differentially expressed genes associated with the formation of liver injury, the experimental mice were randomly divided into the normal group for controlling and the immunologically liver-injured group induced by BCG and LPS. The liver mRNA of the two groups were extracted respectively and reversely-transcribed to cDNA with the incorporation of different fluorescence (Cy3, Cy5) labeled dUTP as the hybridization probes. The mixed probes were hybridized to the cDNA microarray chips. The fluorescent signal results were acquired by scanner ScanArray 4000 and analyzed with software GenePix Pro 3.0. Among the 14112 target genes, 293 genes were found to be significantly differentially expressed, in which 188 genes were up-regulated and 105 genes were down-regulated. Based on the analysis of biological functions of those differentially expressed genes, it was indicated that the occurrence and development of mouse liver damage induced by BCG and LPS were highly correlated with the processes of immune reactions, cell synthesis, metabolism, apoptosis and transportation in liver cell, which might be quite important for elucidating the regulatory network of gene expression associated with the liver damage, also important for finally discovering the pathogenic mechanisms of immunological liver damage.     

Multiple gene action determining a mouse salivary protein phenotype: Identification of the structural gene for androgen binding protein (Abp)

A novel variation in electrophoretic phenotype is described for a mouse salivary androgen binding protein (Abp). Crosses show that the variation is inherited in an autosomal codominant manner and protein characterization studies show that the variant Abp differs in isoelectric point from the common form of the protein. Those observations suggest that the variation involves the structural gene for the mouse salivary Abp. The genetic studies also show that the electrophoretic mobility of the variant Abp can be influenced by the sex-limited saliva pattern (Ssp) gene. The Ssp ^S allele alters the electrophoretic mobility of Abp in males at puberty or in females which have received exogenous testosterone [Karn, R. C., Dlouhy, S. R., Springer, K. R., Hjorth, J. P., and Nielsen, J. T. (1982). Biochem Genet. 20:493]. This study shows that Abp and Ssp are distinct genes which are not closely linked and that Ssp ^S is trans active in F₁ (Abp ^a /Abp ^b , Ssp ^S /Ssp ^F ) males.SRD was supported in part by PHS General Medical Training Grant T32 GMO7468 and the Indiana University School of Medicine Research Program in Academic Medicine. RCK was supported in part by PHS Career Development Award 1 KO4 AMOO284.     

小鼠胎肝细胞透明质酸3D培养体系的建立

目的 利用透明质酸建立小鼠胎肝细胞3D培养体系。 方法 分离获得胚胎12-14天胎肝细胞,利用KM培养基进行初步2D肝干/祖细胞的筛选培养,并利用透明质酸及KM培养基配制水凝胶建立3D细胞培养体系。 结果 胎肝细胞在2D体系中呈现克隆状生长。分离培养获得的肝干/祖细胞克隆在透明质酸建立的3D培养体系保持增殖活性,并进一步获得肝细胞功能特性,表现为3D培养上清中白蛋白合成和尿素水平显著增加。Q-PCR结果显示随着3D培养时间的延长,其肝细胞干性标志如AFP、CK19、EpCAM、Prox1等表达水平都大幅度降低且接近成年小鼠肝脏表达水平。 结论 本研究成功建立基于透明质酸的小鼠胎肝细胞的3D无血清培养体系,并可促进小鼠胎肝细胞肝细胞功能进一步成熟。     

Reciprocal influence of connexins and apical junction proteins on their expressions and functions

Membranes of adjacent cells form intercellular junctional complexes to mechanically anchor neighbour cells (anchoring junctions), to seal the paracellular space and to prevent diffusion of integral proteins within the plasma membrane (tight junctions) and to allow cell-to-cell diffusion of small ions and molecules (gap junctions). These different types of specialised plasma membrane microdomains, sharing common adaptor molecules, particularly zonula occludens proteins, frequently present intermingled relationships where the different proteins co-assemble into macromolecular complexes and their expressions are co-ordinately regulated. Proteins forming gap junction channels (connexins, particularly) and proteins fulfilling cell attachment or forming tight junction strands mutually influence expression and functions of one another.     

Rudimentary pedal grasping in mice and implications for terminal branch arboreal quadrupedalism

We use an outbred laboratory mouse strain (ICR/CD‐1, Charles River Laboratories, Inc.) to model a type of preprimate locomotion associated with rudimentary pedal grasping. Ten male mice were assigned to either control or climbing groups (n = 5 per group). Climbing mice lived within a specialized terrarium that included ～7.5 m of thin branches (5 and 10 cm long) with a thickness of 3.3mm, arranged in a reticulated canopy. Food, water, and a nest site were placed among the branches. To discourage mice from palmigrade or digitigrade locomotion, the floor of the terrarium was flooded with a few centimeters of water. Climbing mice were placed in this setting upon weaning and reared for 3 months until they were mature in size. Litter, and age‐matched controls were also maintained for comparison with climbers. Climbing mice quickly acclimated to the requirements of the fine‐branch model using the foot and tail for grasping and balance. At maturity, climbing and control mice exhibited minor, but significant, morphological plasticity. For climbers, this includes a greater angle of the femoral neck, larger patellar groove index, relatively shorter talar neck length, and more circular talar head aspect ratio (P < 0.10). Climbers also exhibit increased curvature of the distal third metacarpal, decreased talar head angle, and relatively longer caudal vertebrae transverse processes (P < 0.05). These results in a small‐bodied eutherian mammal suggest that facultative hallucial opposability and coordinated tail use enable a kind of grasping active arboreal quadrupedality relevant to the latest stages of pre‐euarchontan evolution. In light of these data, we hypothesize that a unique advantage of mouse‐sized mammals is that they exhibit a highly flexible body plan allowing them to engage in a diverse array of anatomical positions without requiring specific limb morphologies. J. Morphol.,2011. © 2010 Wiley‐Liss, Inc.     

Psychosine-induced alterations in peroxisomes of twitcher mouse liver

Krabbe disease is a neuroinflammatory disorder in which galactosylsphingosine (psychosine) accumulates in nervous tissue. To gain insight into whether the psychosine-induced effects in nervous tissue extend to peripheral organs, we investigated the expression of cytokines and their effects on peroxisomal structure/functions in twitcher mouse liver (animal model of Krabbe disease). Immunofluorescence analysis demonstrated TNF-α and IL-6 expression, which was confirmed by mRNAs quantitation. Despite the presence of TNF-α, lipidomic analysis did not indicate a significant decrease in sphingomyelin or an increase in ceramide fractions. Ultrastructural analysis of catalase-dependent staining of liver sections showed reduced reactivity without significant changes in peroxisomal contents. This observation was confirmed by assaying catalase activity and quantitation of its mRNA, both of which were found significantly decreased in twitcher mouse liver. Western blot analysis demonstrated a generalized reduction of peroxisomal matrix and membrane proteins. These observations indicate that twitcher mouse pathobiology extends to the liver, where psychosine-induced TNF-α and IL-6 compromise peroxisomal structure and functions.