Polymorphisms at 13 expressed human sequences containing CAG/CTG repeats and analysis in autosomal dominant cerebellar ataxia (ADCA) patients

Genetic anticipation – increasing severity and a decrease in the age of onset with successive generations of a pedigree – is clearly present in autosomal dominant cerebellar ataxia (ADCA). Anticipation is correlated with expansion of the CAG/CTG repeat sequence to sizes above those in the normal range through the generations of a pedigree. Genetic heterogeneity has been demonstrated for ADCA, with four cloned genes (SCA1, SCA2, SCA3/MJD, and SCA6) and three mapped loci (SCA4, SCA5 and SCA7). Another related dominant ataxia, dentatorubral-pallidoluysian atrophy (DRPLA), presents anticipation with CAG/CTG repeat expansions. We had previously analysed ADCA patients who had not shown repeat expansions in cloned genes for CAG/CTG repeat expansions by the repeat expansion detection method (RED) and had detected expansions of between 48 and 88 units in 17 unrelated familial cases. We present here an analysis of 13 genes and expressed sequence tags (ESTs) containing 10 or more CAG/ CTG repeat sequences selected from public databases in the 17 unrelated ADCA patients. Of the 13 selected genes and ESTs, 9 were found to be polymorphic with heterozygosities ranging between 0.09 and 0.80 and 2 to 17 alleles. In ADCA patients none of the loci showed expansions above the normal range of the CAG/CTG repeat sequences, excluding them as the mutation causing ADCA. Received: 28 May 1997 / Accepted: 30 June 1997     

Chimeric contribution of human extended pluripotent stem cells to monkey embryos ex vivo

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Postmortem stability of somatostatin-like immunoreactivity in mouse brain under conditions simulating handling of human autopsy material

The postmortern stability of somatostatin-like immunoreactivity (SLI) has been investigated in mice cooled after death at a rate which approximates the rate of cooling of the human brain in situ under normal mortuary conditions. Significant changes in SLI levels were observed within the first few hours after death, but concentrations measured 6–24 hr after death seem to be similar to those existing at the time of death.     

Bio-mediated soil improvement

New, exciting opportunities for utilizing biological processes to modify the engineering properties of the subsurface (e.g. strength, stiffness, permeability) have recently emerged. Enabled by interdisciplinary research at the confluence of microbiology, geochemistry, and civil engineering, this new field has the potential to meet society's ever-expanding needs for innovative treatment processes that improve soil supporting new and existing infrastructure. This paper first presents an overview of bio-mediated improvement systems, identifying the primary components and interplay between different disciplines. Geometric compatibility between soil and microbes that restricts the utility of different systems is identified. Focus is then narrowed to a specific system, namely bio-mediated calcite precipitation of sands. Following an overview of the process, alternative biological processes for inducing calcite precipitation are identified and various microscopy techniques are used to assess how the pore space volume is altered by calcite precipitation, the calcite precipitation is distributed spatially within the pore space, and the precipitated calcite degrades during loading. Non-destructive geophysical process monitoring techniques are described and their utility explored. Next, the extent to which various soil engineering properties is identified through experimental examples. Potential advantages and envisioned applications of bio-mediated soil improvement are identified. Finally, the primary challenges that lie ahead, namely optimization and upscaling of the processes and the education/training of researchers/practitioners are briefly discussed.     

Comparative activity of two cholecystokinin analogues with partial agonist activity: effects on food intake and brain monoamines

Two analogues of the C-terminal heptapeptide of cholecystokinin have been synthesized, in which the C-terminal phenylalanine residue has been replaced by a phenylethylester (JMV 180) or a phenylethylamide (JMV 170) group. They have been shown to present partial agonist CCK activity on pancreatic amylase release. In this study, the effects of the two peptides were investigated on food intake and brain monoamine metabolism after intraperitoneal (IP) and intracerebroventricular (ICV) administration. Neither peptide was active on feeding after IP administration but both decreased food intake after ICV injection, with a slightly higher potency for JMV 170. JMV 180 induced no change in monoamine metabolism whatever the route of administration. JMV 170 IP decreased cortical levels of dopamine and its metabolites. This effect was stronger after ICV injection and was accompanied by changes in serotonergic metabolism in the hypothalamus and cortex. Contrary to CCK8 S, which is more active on feeding after peripheral injection, the feeding effects of the analogues obtained by modification of the C-terminal phenylalanine residue appear to involve a central site of action. Furthermore, phenylethylamide substitution (JMV 170) gives rise to greater potency on monoaminergic variations than replacement with a phenylethylester (JMV 180) and the effect is enhanced following central administration.     

Myocardium proteome remodelling after nutritional deprivation of methyl donors

Methyl donor (MD: folate, vitamin B12 and choline) deficiency causes hyperhomocysteinemia, a risk factor for cardiovascular diseases. However, the mechanisms of the association between MD deficiency, hyperhomocysteinemia, and cardiomyopathy remain unclear. Therefore, we performed a proteomic analysis of myocardium of pups from rat dams fed a MD-depleted diet to understand the impact of MD deficiency on heart at the protein level. Two-dimension gel electrophoresis and mass spectrometry-based analyses allowed us to identify 39 proteins with significantly altered abundance in MD-deficient myocardium. Ingenuity Pathway Analysis showed that 87% of them fitted to a single protein network associated with developmental disorder, cellular compromise and lipid metabolism. Concurrently increased protein carbonylation, the major oxidative post-translational protein modification, could contribute to the decreased abundance of many myocardial proteins after MD deficiency. To decipher the effect of MD deficiency on the abundance of specific proteins identified in vivo, we developed an in vitro model using the cardiomyoblast cell line H9c2. After a 4-day exposure to a MD-deprived (vs. complete) medium, cells were deficient of folate and vitamin B12, and released abnormal amounts of homocysteine. Western blot analyses of pup myocardium and H9c2 cells yielded similar findings for several proteins. Of specific interest is the result showing increased and decreased abundances of prohibitin and α-crystallin B, respectively, which underlines mitochondrial injury and endoplasmic reticulum stress within MD deficiency. The in vitro findings validate the MD-deficient H9c2 cells as a relevant model for studying mechanisms of the early metabolic changes occurring in cardiac cells after MD deprivation.     

Derived structure of the putative sialic acid transporter from Escherichia coli predicts a novel sugar permease domain.

Catabolism of sialic acids by Escherichia coli requires the genes nanA and nanT, which were previously mapped between argG and rpoN (E.R. Vimr and F.A. Troy, J. Bacteriol. 164:845-853, 1985). This organization is confirmed and extended by physical mapping techniques. An open reading frame beginning 135 bp from the nanA translational stop codon could code for a 53,547-Da hydrophobic polypeptide predicted to contain 14 transmembrane segments. Complementation analysis confirmed that nanT is required for sialic acid uptake when expressed in trans. NanT is homologous to a putative permease encoded by open reading frame 425, which maps between leuX and fecE in the E. coli chromosome. However, unlike this hypothetical permease or previously reported monosaccharide transporters, NanT contains a centrally located domain with two additional potential membrane-spanning segments plus one amphiphilic alpha-helix that may be important for the structure and function of sialic acid-permease.     

Expression of alkaline phosphatase in murine B lymphocytes. Correlation with B cell differentiation into Ig secretion

Alkaline phosphatases (ALPase) (orthophosphoric-monoester phosphohydrolase, EC 3.1.3.1) are implicated in many biologic phenomena including ossification and differentiation of human neutrophils and choriocarcinoma cells. Another trait, demonstrated by microinjection into Xenopus oocytes, is their ability to block the first mitotic division. Previous work in our laboratory has established that ALPase is also present on murine B lymphocytes activated by either polyclonal mitogens or Th cells. We have now characterized the ALPase present on murine B cells as belonging to the liver-bone-kidney isoenzyme and found it to be implicated in B cell differentiation into antibody secretion. Thus, B cell proliferative responses, elicited either by high concentrations of rabbit anti-IgM antibodies or by LPS in the presence of PMA, are characterized by the lack of both antibody secretion and expression of ALPase activity. In contrast, B cells stimulated to differentiate into Ig-secreting cells by B cell differentiation factors, nearly in the absence of a proliferative response, express high levels of ALPase activity, as did those that were LPS-stimulated. These data showing the association of the ALPase expression with the process of B cell differentiation into antibody-secreting cells are discussed in the context of the possible role that phosphorylation-dephosphorylation mechanism may play in controlling the growth/differentiation rate in the B cell lineage.