Parallel and interrelated neural systems underlying adaptive navigation

The ability to process in parallel multiple forms of sensoryinformation, and link sensory-sensory associations to behavior,presumably allows for the opportunistic use of the most reliableand predictive sensory modalities in diverse behavioral contexts.Evolutionary considerations indicate that such processing mayrepresent a fundamental operating principle underlying complexsensory associations and sensory-motor integration. Here, wesuggest that animal navigation is a particularly useful modelof such opportunistic use of sensory and motor information becauseit is possible to study directly the effects of memory on neuralsystem functions. First, comparative evidence for parallel processingacross multiple brain structures during navigation is providedfrom the literatures on fish and rodent navigation. Then, basedon neurophysiological evidence of coordinated, multiregionalprocessing, we provide a neurobiological explanation of learningand memory effects on neural circuitry mediating navigation.     

Immunophenotyping and activation status of maternal peripheral blood leukocytes during pregnancy and labour,both term and preterm

The onset of labour in rodents and in humans is associated with physiological inflammation which is manifested by infiltration of activated maternal peripheral leukocytes (mPLs) into uterine tissues. Here, we used flow cytometry to immunophenotype mPLs throughout gestation and labour, both term and preterm. Peripheral blood was collected from non‐pregnant women and pregnant women in the 1st, 2nd and 3rd trimesters. Samples were also collected from women in active labour at term (TL) or preterm (PTL) and compared with women term not‐in‐labour (TNIL) and preterm not‐in‐labour (PTNIL). Different leukocyte populations were identified by surface markers such as CD45, CD14, CD15, CD3, CD4, CD8, CD19 and CD56. Their activation status was measured by the expression levels of CD11b, CD44, CD55, CD181 and CD192 proteins. Of all circulating CD45+ leukocytes, we detected significant increases in CD15+ granulocytes (i) in pregnant women versus non‐pregnant; (ii) in TL women versus TNIL and versus pregnant women in the 1st/2nd/3rd trimester; (iii) in PTL women versus PTNIL. TL was characterized by (iv) increased expressions of CD11b, CD55 and CD192 on granulocytes; (v) increased mean fluorescent intensity (MFI) of CD55 and CD192 on monocytes; (vi) increased CD44 MFI on CD3+ lymphocytes as compared to late gestation. In summary, we have identified sub‐populations of mPLs that are specifically activated in association with gestation (granulocytes) or with the onset of labour (granulocytes, monocytes and lymphocytes). Additionally, beta regression analysis created a set of reference values to rank this association between immune markers of pregnancy and to identify activation status with potential prognostic and diagnostic capability.     

Endogenous butyrylcholinesterase in SV40 transformed cell lines: COS-1, COS-7, MRC-5 SV40, and WI-38 VA13

Summary Comparison of proteins expressed by SV40 transformed cell lines and untransformed cell lines is of interest because SV40 transformed cells are immortal, whereas untransformed cells senesce after about 50 doublings. In MRC-5 SV40 cells, only seven proteins have previously been reported to shift from undetectable to detectable after transformation by SV40 virus. We report that butyrylcholinesterase is an 8th protein in this category. Butyrylcholinesterase activity in transformed MRC-5 SV40 cells increased at least 150-fold over its undetectable level in MRC-5 parental cells. Other SV40 transformed cell lines, including COS-1, COS-7, and WI-38 VA13, also expressed endogenous butyrylcholinesterase, whereas the parental, untransformed cell lines, CV-1 and WI-38, had no detectable butyrylcholinesterase activity or mRNA. Infection of CV-1 cells by SV40 virus did not result in expression of butyrylcholinesterase, showing that the butyrylcholinesterase promoter was not activated by the large T antigen of SV40. We conclude that butyrylcholinesterase expression resulted from events related to cell immortalization and did not result from activation by the large T antigen.     

Classification of ATP-dependent proteases Lon and comparison of the active sites of their proteolytic domains.

ATP-dependent Lon proteases belong to the superfamily of AAA+ proteins. Until recently, the identity of the residues involved in their proteolytic active sites was not elucidated. However, the putative catalytic Ser-Lys dyad was recently suggested through sequence comparison of more than 100 Lon proteases from various sources. The presence of the catalytic dyad was experimentally confirmed by site-directed mutagenesis of the Escherichia coli Lon protease and by determination of the crystal structure of its proteolytic domain. Furthermore, this extensive sequence analysis allowed the definition of two subfamilies of Lon proteases, LonA and LonB, based on the consensus sequences in the active sites of their proteolytic domains. These differences strictly associate with the specific characteristics of their AAA+ modules, as well as with the presence or absence of an N-terminal domain.     

Metallothionein isoform 2A expression is inducible and protects against ROS-mediated cell death in rotenone-treated HeLa cells

The role of MT (metallothionein) gene expression was investigated in rotenone-treated HeLa cells to induce a deficiency of NADH:ubiquinone oxidoreductase (complex I). Complex I deficiency leads to a diversity of cellular consequences, including production of ROS (reactive oxygen species) and apoptosis. HeLa cells were titrated with rotenone, resulting in dose-dependent decrease in complex I activity and elevated ROS production at activities lower than 33%. Expression of MT2A (MT isoform 2A), but not MT1A or MT1B RNA, was significantly inducible by rotenone (up to 7-fold), t-BHP (t-butyl hydroperoxide; 5-fold) and CdCl2 (50-fold), but not ZnCl2. Myxothiazol treatment did not elevate either ROS or MT2A levels, which supports a ROS-related mechanism for rotenone-induced MT2A expression. To evaluate the role of MT2A expression, MT2A and MT1B were overexpressed in HeLa cells and treated with rotenone. Compared with control and MT1B-overexpressing cells, ROS production was significantly lower and cell viability higher in MT2A-overexpressing HeLa cells when ROS production was enhanced by treatment with t-BHP. Mitochondrial membrane potential was noticeably less reduced in both MT-overexpressing cell lines. MT2A overexpression in rotenone-treated cells also significantly reduced or delayed apoptosis induction, as measured by caspase 3/7 activity and cytosolic nucleosome enrichment. We conclude that MT2A offers significant protection against the main death-causing consequences of rotenone-induced complex I deficiency in HeLa cells. Our results are in support of the protective role against oxidative stress ascribed to MTs and provide evidence that MT2A expression may be a beneficial downstream adaptive response in complex I-deficient cells.     

Pallister-Killian syndrome: rapid decrease of isochromosome 12p frequency during amniocyte subculturing. Conclusion for strategy of prenatal cytogenetic diagnostics.

Pallister-Killian syndrome (PKS) is characterized cytogenetically by mosaic tetrasomy of chromosome 12p. Routine prenatal diagnosis of PKS is still complicated because of the difficulties of discriminating between the supernumerary isochromosome 12p and the duplication 21q and because of the variable level of mosaicism. The frequency of cells with an extra metacentric chromosome i(12)(p10) is usually determined by tissue-limited or tissue-specific mosaicism. We demonstrated a decrease of the abnormal clone with extra i(12p) in the amniotic fluid cells of the PKS fetus during amniocyte subculturing. The rapid loss of the i(12p) in the course of amniocyte subculturing should be the focus of attention during prenatal karyotyping. This is especially necessary for cultures with slow growth, which require further interpretation of the result during cytogenetic diagnosis of PKS.     

Immunological comparison of the usual and atypical human serum cholinesterase phenotypes

Antiserum prepared against highly purified usual human serum cholinesterase (the most common phenotype) cross-reacted identically with the atypical serum cholinesterase. The level of circulating atypical enzyme protein, determined immunologically, was about 30% lower when the enzyme came from an atypical rather than a usual phenotype, and the level of enzyme activity measured enzymatically atV _max with eithero-nitrophenylbutyrate or benzoylcholine as substrate showed approximately the same degree of reduction. The average specific activity (activity atV _max per microgram of enzyme protein) in sera from 28 usual and 20 atypical individuals did not differ significantly. These findings suggest that the atypical enzyme not only has altered catalytic properties (K)_mbut also might be synthesized more slowly, or clearedin vivo more rapidly, than the usual enzyme. This work was supported by U.S. Public Health Service Grants NS 15871 and GM 27028 and by a grant from the Hoffmann-La Roche Foundation.