Geometric morphometrics defines shape differences in the cortical area map of C57BL/6J and DBA/2J inbred mice

Background  

We previously described planar areal differences in adult mouse visual, somatosensory, and neocortex that collectively discriminated C57BL/6J and DBA/2J inbred strain identity. Here we use a novel application of established methods of two-dimensional geometric morphometrics to examine shape differences in the cortical area maps of these inbred strains.     

MRI effects on the teratogenicity of x-irradiation in the C57BL/6J mouse

This investigation was undertaken in order to ascertain the combined effects of magnetic resonance imaging (MRI) fields and x-irradiation on the developing eye of the mouse strain C57B1/6J. Dams in groups of 15 were subjected to absorbed doses of 5, 15, and 30 cGy. Other dams (N = 15) were exposed to T2 spin-echo MRI fields under clinically realistic conditions following exposure to 30 cGy of x-irradiation. The developing eye was the biological end point studied. It was found that the 30-cGy dose resulted in teratogenic significance (p less than or equal to .05) for the C57B1/6J mouse. Groups exposed to both types of radiation fields demonstrated malformation levels similar to the 30-cGy irradiated animals with no additive or synergistic effects detected. The malformation rates and degree of statistical significance varied somewhat with unit of measurement, and analytical method. The results confirmed low level X-ray teratogenicity and suggested that the MRI techniques employed for this investigation did not enhance the teratogenicity of x-irradiation on eye malformations produced in the C57B1/6J mouse.     

Progressive ganglion cell loss and optic nerve degeneration in DBA/2J mice is variable and asymmetric

Background  

Glaucoma is a chronic neurodegenerative disease of the retina, characterized by the degeneration of axons in the optic nerve and retinal ganglion cell apoptosis. DBA/2J inbred mice develop chronic hereditary glaucoma and are an important model system to study the molecular mechanisms underlying this disease and novel therapeutic interventions designed to attenuate the loss of retinal ganglion cells. Although the genetics of this disease in these mice are well characterized, the etiology of its progression, particularly with respect to retinal degeneration, is not. We have used two separate labeling techniques, post-mortem DiI labeling of axons and ganglion cell-specific expression of the βGeo reporter gene, to evaluate the time course of optic nerve degeneration and ganglion cell loss, respectively, in aging mice.     

Deletion of the alpha-synuclein locus in a subpopulation of C57BL/6J inbred mice

Background  

The presynaptic protein α-synuclein is involved in a range of neurodegenerative diseases. Here we analyze potential compensatory mechanisms in α-synuclein null mutant mice. Furthermore, the findings reveal problems that may be associated with inbred mouse strains.     

Comparison of the responses of the chorda tympani and glossopharyngeal nerves to taste stimuli in C57BL/6J mice

Background

Recent progress in discernment of molecular pathways of taste transduction underscores the need for comprehensive phenotypic information for the understanding of the influence of genetic factors in taste. To obtain information that can be used as a base line for assessment of effects of genetic manipulations in mice taste, we have recorded the whole-nerve integrated responses to a wide array of taste stimuli in the chorda tympani (CT) and glossopharyngeal (NG) nerves, the two major taste nerves from the tongue.

Results

In C57BL/6J mice the responses in the two nerves were not the same. In general sweeteners gave larger responses in the CT than in the NG, while responses to bitter taste in the NG were larger. Thus the CT responses to cyanosuosan, fructose, NC00174, D-phenylalanline and sucrose at all concentrations were significantly larger than in the NG, whereas for acesulfame-K, L-proline, saccharin and SC45647 the differences were not significant. Among bitter compounds amiloride, atropine, cycloheximide, denatonium benzoate, L-phenylalanine, 6-n-propyl-2-thiouracil (PROP) and tetraethyl ammonium chloride (TEA) gave larger responses in the NG, while the responses to brucine, chloroquine, quinacrine, quinine hydrochloride (QHCl), sparteine and strychnine, known to be very bitter to humans, were not significantly larger in the NG than in the CT.

Conclusion

These data provide a comprehensive survey and comparison of the taste sensitivity of the normal C57BL/6J mouse against which the effects of manipulations of its gustatory system can be better assessed.

     

Serum and aqueous humour cytokine response and histopathological alterations during ocular Toxoplasma gondii infection in C57BL/6 mice

Toxoplasma gondii, an obligate intracellular protozoan parasite, infects most species of warm-blooded animals, and in humans it causes toxoplasmosis. Healthy people that become infected rarely present clinical symptoms because the immune system prevents the parasite from causing illness. Congenital toxoplasmosis may result in abortion, hydrocephalus, as well as neurological and ocular disease (most frequently retinochoroiditis) of the newborn. In immunocompromised patients, reactivation of latent disease can cause encephalitis. Cell-mediated immunity to T. gondii antigens involves innate acute inflammatory responses and antigen-specific adaptive immunity. Considering the complexity of the immunological events triggered during toxoplasmosis, systemic and local responses were evaluated by cytokine measurements. Aqueous humour and serum were obtained from non-infected and T. gondii Me-49 strain infected C57BL/6 mice for cytokine quantification. Histopathological analyses were made with eyes enucleated from mice after 30 days of infection. ELISA assays showed an increase of IFN-γ levels both in serum and aqueous humour of infected mice in opposition to a decrease in IL-10 levels. On the other hand, TGF-β was high, whereas IL-12 and TNF-α were present in small levels in both groups. We also detected higher levels of IL-4 and IL-6 in aqueous humour than in serum of infected mice when compared to the control group. MIP-2 presented no significant differences between the two groups. Fas and Fas-L were also present in similar levels in serum of non-infected and infected mice, but both chemokines were increased in the aqueous humour of infected mice. Histopathological analysis of infected mice showed inflammatory infiltrates around blood vessels and alteration of the outer photoreceptor segments, on the external and inner nuclear layer. Parasites were observed in 82% of eyes, inside the blood vessels associated with inflammatory infiltrate. Edema, characterized by the increase of interstitial spaces between the FTR, forming lacunae was also noted. These alterations take the form of projections (retino-vitreal), characteristic of retinochoroiditis. In conclusion, T. gondii infection of C57BL/6 mice revealed that cytokine patterns alone do not assure susceptibility or resistance against infection, thus reinforcing the notion that it is necessary more than cytokine dosage to determine Th1 or Th2 profile in this model.     

不同性别C57BL/6小鼠肠道胆汁酸组成的差异性研究

随着人们对宿主肠道菌群的日益关注,关于胆汁酸与肠道菌群之间复杂关系的研究也越来越多.因肠道组织结构的复杂性和肠道菌群分布差异性,不同肠段胆汁酸的分布、表达及其生物学功能仍有待进一步研究.本文采用基于超高效液相色谱-三重四极杆-质谱联用（UPLC-QqQ-MS）的靶向代谢组分析结合基于核磁共振（NMR）波谱的非靶向代谢组分析方法,通过比较不同性别C57BL/6小鼠肠道各区段胆汁酸及粪样代谢组的变化水平,发现雌、雄小鼠不同肠段中胆汁酸的分布各不相同.另外,肠道下段各胆汁酸的性别差异性更为明显,以盲肠的性别差异性最为显著,这可能与盲肠的菌群微生态更为丰富有关.该研究为不同性别模型小鼠胆汁酸的代谢表型及其与肠道菌群的相互作用提供了基础研究数据.     

Region-Specific Susceptibilities to Cuprizone-Induced Demyelination of C57BL/6 Mouse: In vivo T2WI and DTI Studies at 7.0T

The cuprizone (CPZ) mouse model of demyelination was recognized and used to explore multiple sclerosis (MS)-like brain lesions. In this study, we assessed CPZ-treated mice using T₂-weighted imaging and diffusion tensor imaging (DTI). C57BL/6 mice treated with 2 weeks of 0.2 % CPZ-containing diet (n = 10) and regular chow diet (n = 10) were scanned with a 7.0 T MRI scanner (Agilent, USA), respectively, using fast spin-echo and fast spin-echo DTI sequences. The normalized T₂ signal intensity (normalized to the cerebrospinal fluid) was calculated and fractional anisotropy (FA value), mean diffusivity, axial diffusivity and radial diffusivity were measured in the brain region of the cerebral cortex (CTX), caudate putamen (CP), hippocampus (HP) and thalamus (TH). Compared with controls, increased normalized T₂ signal intensities and reduced FA values (p < 0.05) were observed in the CTX, HP and CP (p < 0.01), but not in TH in cuprizone-fed mice. In the regions of reduced FA values, an increase in mean diffusivity (p < 0.05) and radial diffusivity (p < 0.05) was also found. Significant decreased axial diffusivity was only observed in CTX (p < 0.05). DTI is sensitive to detecting cuprizone-induced demyelination of C57BL/6 mice. This study suggests that CTX, HP and CP are more susceptible to cuprizone-induced demyelination than TH. Our results also indicate that the decrease of FA value may be more likely due to increased radial diffusivity.     

Dominant inheritance of retinal ganglion cell resistance to optic nerve crush in mice

Background  

Several neurodegenerative diseases are influenced by complex genetics that affect an individual's susceptibility, disease severity, and rate of progression. One such disease is glaucoma, a chronic neurodegenerative condition of the eye that targets and stimulates apoptosis of CNS neurons called retinal ganglion cells. Since ganglion cell death is intrinsic, it is reasonable that the genes that control this process may contribute to the complex genetics that affect ganglion cell susceptibility to disease. To determine if genetic background influences susceptibility to optic nerve damage, leading to ganglion cell death, we performed optic nerve crush on 15 different inbred lines of mice and measured ganglion cell loss. Resistant and susceptible strains were used in a reciprocal breeding strategy to examine the inheritance pattern of the resistance phenotype. Because earlier studies had implicated Bax as a susceptibility allele for ganglion cell death in the chronic neurodegenerative disease glaucoma, we conducted allelic segregation analysis and mRNA quantification to assess this gene as a candidate for the cell death phenotype.     

Dopamine D<Subscript>2</Subscript>receptors mediate two-odor discrimination and reversal learning in C57BL/6 mice

Background  

Dopamine modulation of neuronal signaling in the frontal cortex, midbrain, and striatum is essential for processing and integrating diverse external sensory stimuli and attaching salience to environmental cues that signal causal relationships, thereby guiding goal-directed, adaptable behaviors. At the cellular level, dopamine signaling is mediated through D₁-like or D₂-like receptors. Although a role for D₁-like receptors in a variety of goal-directed behaviors has been identified, an explicit involvement of D₂ receptors has not been clearly established. To determine whether dopamine D₂ receptor-mediated signaling contributes to associative and reversal learning, we compared C57Bl/6J mice that completely lack functional dopamine D₂ receptors to wild-type mice with respect to their ability to attach appropriate salience to external stimuli (stimulus discrimination) and disengage from inappropriate behavioral strategies when reinforcement contingencies change (e.g. reversal learning).     

JAK/STAT通路抑制剂对C57BL/6小鼠血清代谢组影响的1H NMR研究

JAK/STAT通路抑制剂已被应用于多种疾病的临床试验,但其全身性用药对机体组织细胞功能活性的影响目前尚不明确.本研究运用基于核磁共振氢谱（¹H NMR）的代谢组学方法分析了JAK/STAT通路抑制剂WP1066（20 mg/kg.bw,2天一次,持续2周）对C57BL/6小鼠血清代谢组的影响.首先采用¹H NMR技术检测了WP1066处理组和对照组小鼠血清的代谢物,然后对所得的图谱数据进行了主成分分析（PCA）以及正交偏最小二乘法分析（OPLS）.研究结果表明,抑制JAK/STAT通路可明显下调小鼠血清中的N-甲基烟酰胺（N-methylnicotinamide）水平,而上调顺乌头酸（cis-aconitate）、草酰乙酸（oxaloacetate）和乙酰胺（acetamide）水平,这些代谢物改变均与能量代谢密切相关.该结果提示代谢失衡相关指标可能作为JAK/STAT通路抑制剂治疗的临床监测参考指标.     

Inducible nitric oxide synthase, <Emphasis Type="Italic">Nos2</Emphasis>, does not mediate optic neuropathy and retinopathy in the DBA/2J glaucoma model

Background  

Nitric oxide synthase 2 (NOS2) contributes to neural death in some settings, but its role in glaucoma remains controversial. NOS2 is implicated in retinal ganglion cell degeneration in a rat glaucoma model in which intraocular pressure (IOP) is experimentally elevated by blood vessel cauterization, but not in a rat glaucoma model where IOP was elevated by injection of hypertonic saline. To test the importance of NOS2 for an inherited glaucoma, in this study we both genetically and pharmacologically decreased NOS2 activity in the DBA/2J mouse glaucoma model.     

Infrared intensity analysis of molecules C2H6, C2D6, C2F6 and CF4 zero and first order approximations

Infrared intensity formulae for C₂H₆ and C₂D₆ are derived following the first order approximations. Using the experimental intensities in the intensity equations, the first order coefficients are calculated. They are observed to be negligible compared to the accuracy limits within which the intensities can be measured. Correlating the experimental intensities to the intensity expressions of C₂F₆ and following the zero-order approximations, the bond dipole moment μ and its derivative e are calculated for the C–F bond. Substituting these in the intensity equations of CF₄, transferability of the bond moment parameters is discussed.     

Light emission from a-Si:C:O:H films fabricated by C2F6 and O2/C2F6 plasma treating silicone oil liquid

Amorphous Si:C:O:H films were fabricated at low temperature by C₂F₆ and O₂/C₂F₆ plasma treating silicone oil liquid. The a-Si:C:O:H films fabricated by C₂F₆ plasma treatment exhibited white photoluminescence at room temperature, while that by O₂/C₂F₆ plasma treatment exhibited blue photoluminescence. Fourier transformed infrared spectroscopy and Raman spectroscopy studies showed that the sp³ and sp² hybridized carbons, SiC bond, SiO bond and carbon-related defects in a-Si:C:O:H films correlated with photoluminescence. It is suggested that the blue emission at 469 nm was related to the sp³ and sp² hybridized carbons, SiC bond, carbon dangling bonds as well as SiO short chains and small clusters, while the light emitting at 554 nm was related to the carbon-related defects.     

Magnetoelectric response of new Sr2TiMnO6 manganite-like material

We report synthesis and characterization of new Sr₂TiMnO₆ manganite-like material. Samples were produced by the solid state reaction method. X-ray diffraction experiments reveal the presence of peaks, which are characteristics of the complex perovskite systems. Rietveld refinement showed that Sr₂TiMnO₆ crystallizes in a tetragonal structure, which corresponds to the space group I/4m. From measurements of magnetization as a function of temperature, we determine the occurrence of magnetic ordering for a critical temperature T_C=44.8 K and strong evidence of frustration. Curves of magnetization as a function of applied field show hysteretic behavior. Curves of polarization as a function of applied voltage exhibit the ferroelectric response of Sr₂TiMnO₆ material. Results reveal the occurrence of magnetoelectric response for the temperature regime T<44.8 K.     

电激励脉冲HF激光SF_6/C_2H_6工作气体的放电特性

研究了电激励脉冲HF激光工作介质SF6/C2H6混合气体的放电特性。通过对放电等离子体荧光图像和放电波形的测量,分析比较了不同条件下放电稳定性、剩余电压、能量沉积效率等特性参数的变化情况。实验结果表明:混合气体的放电过程存在主放电、剩余电压维持和电弧放电3个阶段,各阶段的放电特性有所差异;提高充电电压有利于放电能量的有效沉积,也会使不稳定的电弧放电提前;增加C2H6原子分数能起到抑制电弧放电的作用;混合气体总压的增加会导致剩余电压的提高以及辉光放电的能量沉积效率的降低;最佳的能量沉积出现在电弧放电阶段与辉光放电阶段即将融合的临界状态。     

Study of Ba 6p1/2ns (J=0,1) autoionizing series

With different polarization configurations the spectroscopic properties of Ba 6p_1/2ns (J=0) and 6p_1/2ns (J=1) autoionizing states have been studied systematically by using an isolated core excitation scheme. Level energies and widths of n members for the J=1 series with n=9–33 and for the J=0 series with n=9–10,12–20 are reported, most of which are observed for the first time. Further information about these two autoionizing series, such as energies of the higher n members and their interseries interactions with 6p_3/2nl series, are obtained by means of saturation excitation method. The experimental data on the J=1 series are analyzed with a 13-channel multichannel quantum defect theory, and general agreement between them has been obtained. Several parts of the experimental results are compared with those of previous works, and agree well with them.     

C1与C3D6H2和C3H6D2反应的立体动力学对比研究

在扩展的London-Eyring-Polanyi-Sato（LEPS）势能面上，利用准经典轨线法研究了碰撞能为Ecol=6．0kcal／mol时C1与C3D6H2和C3H6D2反应．在质心系中计算了极化微分反应截（2π／σ）（dσ00／dωt）、两矢量相关的P（θr）分布、三矢量相关的极角分布P（Ф）以及用θr和Фr表示的产物转动角动量的空间分布，计算结果与有关实验及理论结果符合得很好．通过对比研究C1与C3D6H2、C3H6功和C3H8在不同碳位上的反应，发现质量因子在此类反应中起着重要的作用．