Gene Expression Profiling of Lymphoblasts from Autistic and Nonaffected Sib Pairs: Altered Pathways in Neuronal Development and Steroid Biosynthesis

Despite the identification of numerous autism susceptibility genes, the pathobiology of autism remains unknown. The present “case-control” study takes a global approach to understanding the molecular basis of autism spectrum disorders based upon large-scale gene expression profiling. DNA microarray analyses were conducted on lymphoblastoid cell lines from over 20 sib pairs in which one sibling had a diagnosis of autism and the other was not affected in order to identify biochemical and signaling pathways which are differentially regulated in cells from autistic and nonautistic siblings. Bioinformatics and gene ontological analyses of the data implicate genes which are involved in nervous system development, inflammation, and cytoskeletal organization, in addition to genes which may be relevant to gastrointestinal or other physiological symptoms often associated with autism. Moreover, the data further suggests that these processes may be modulated by cholesterol/steroid metabolism, especially at the level of androgenic hormones. Elevation of male hormones, in turn, has been suggested as a possible factor influencing susceptibility to autism, which affects ∼4 times as many males as females. Preliminary metabolic profiling of steroid hormones in lymphoblastoid cell lines from several pairs of siblings reveals higher levels of testosterone in the autistic sibling, which is consistent with the increased expression of two genes involved in the steroidogenesis pathway. Global gene expression profiling of cultured cells from ASD probands thus serves as a window to underlying metabolic and signaling deficits that may be relevant to the pathobiology of autism.     

Characterization of the nematocidal toxocyst in <Emphasis Type="Italic">Pleurotus</Emphasis> subgen. <Emphasis Type="Italic">Coremiopleurotus</Emphasis>

Toxocysts of the genus Pleurotus are blastoconidia-like ovoid structures surrounded by a liquid droplet containing a toxin that paralyzes nematodes. This study investigated toxocyst development using a strain S396 of Pleurotus cystidiosus subsp. abalonus (subgen. Coremiopleurotus). The surface of the liquid droplet was found to be an elastic envelope. When a nematode touches the toxocyst, the envelope adheres to the worm and bursts. Toxocysts are induced simultaneously with coremia formation in the absence of nematodes and developed only from aerial hyphae in which nuclear division had ceased. In the early stage of toxocyst development, liquid springs repeatedly from the tip of the sterigma-like stipe before ovoid (blastoconidium-like structure) formation. A certain substance in the liquid might polymerize to form the envelope while the ovoid simultaneously budded in the droplet. The nucleus tends to locate near the toxocyst, especially in early stage of toxocyst development. Each dikaryotic cell predominantly formed one or two toxocyst(s) while each monokaryotic cell predominantly formed one. In rare cases, a nucleus existed in the toxocyst, suggesting the possibility that the toxocyst is a vestigial blastoconidium.     

High-performance thin-layer chromatographic determination of 5-methoxypsoralen in serum from patients

A simple and rapid high-performance thin-layer chromatographic (HPTLC) determination of 5-methoxypsoralen in serum is necessary for the therapeutic survey of patients treated with Puvatherapy (psoralen+UV A). The assay for this biological fluid involves an extraction with heptane-dichloromethane (4:1, v/v). The analytical method is linear from 50 to 250 ng/ml. This assay range is adequate for analysing human serum, as it corresponds to psoralen concentrations measured in serum from patients treated with psoralen and UV A against psoriasis and vitiligo. The limit of detection is 15 ng/ml. The coefficient of variation was less than 7%.     

Time of Flowering of Pea (Pisum sativum L.) as a Function of Leaf Appearance Rate and Node of First Flower

In order to assess the influence of environmental conditionson time of flowering of pea (Pisum sativum L.), a serial sowingtrial was conducted over 2 years at Dijon, France, on two wintercultivars Frisson and Frilene. Time of flowering was analysedaccording to two variables: the leaf appearance rate R_L andthe node of first flower N_I. R_L was linearly related to temperature (r² = 0·94). Thebase temperature was 2°C for both varieties. Growth rateaccounted for the residual variability of R_L . Photoperiod andtemperature acted on N_I in an additive way. Frilene, the latergenotype, was more responsive than Frisson. A model for predicting time of flowering based upon these resultsis proposed. Deviations from this model were related to N nutritionin interaction with the plant water relations. Steps for improvingthe model are then discussed.Copyright 1993, 1999 Academic Press Pisum sativum L., pea, flowering, temperature, photoperiod, phyllochron, model     

Low density lipoprotein-receptor plays a major role in the binding of very low density lipoproteins and their remnants on HepG2 cells.

The binding to HepG2 cells of very low density lipoproteins (VLDL) and their remnants (IDL) was alternatively, in the past, attributed to the low density lipoprotein receptor (LDLr) or to an apoE-specific receptor. In order to resolve this issue, we have compared the binding of those lipoproteins labelled with iodine-125 to normal and LDLr deficient HepG2 cells. Those deficient cells were obtained by a constitutive antisense strategy and their LDLr level is 14% the level of normal HepG2 cells. By saturation curve analysis, we show that VLDL and IDL bind to high and low affinity sites on cells. The low affinity binding was eliminated by conducting the assay in presence of a 200-fold excess of HDL3 respective to the concentrations of 125I-labelled VLDL and IDL. For 125I-VLDL high affinity binding to normal HepG2 cells, we found a dissociation constant (Kd) of 21.2 +/- 3.7 micrograms prot./ml (S.E., N = 5) and a maximal binding capacity (Bmax) of 0.0312 +/- 0.0063 microgram prot./mg cell prot, while we have measured a Kd of 5.3 +/- 0.8 and a Bmax of 0.0081 +/- 0.0014 with LDLr deficient cells. This indicates that LDLr is responsible for 74% of VLDL binding to HepG2 cells and that the non-LDLr high affinity receptor has a higher affinity for VLDL than LDLr. A 53% loss of 125I-IDL binding capacity was measured with LDLr deficient cells compared with normal cells (Bmax: 0.028 +/- 0.005 versus 0.059 +/- 0.006), while no significant statistical difference was found between affinities. The study shows that the LDLr is almost the only contributor in VLDL binding, while it shares IDL binding capacity with another high affinity receptor. The physiological importance of LDLr is confirmed by an almost equivalent loss of IDL and VLDL degradation in LDLr deficient cells.     

Facultative Ant-Plant Interactions: Nectar Sugar Preferences of Introduced Pest Ant Species in South Florida1

We observed nectar use by native and exotic ant species in nature, garden, and urban situations, and found ants utilizing floral and extrafloral nectar of a variety of flowering plant species. We collected 31 plant nectars (29 floral, 2 extrafloral) and used them in feeding preference tests against standard solutions of sugars (20 percent fructose, glucose, and sucrose, and their mixture), 10 trials for each nectar-ant comparison. We compared time-to-discovery and total ant visits to each droplet using ANOVA, and found that both trial and solution contributed significantly to the variation in most experiments. Seven of the floral nectars tested were significantly more attractive to certain ant species than the sugar solutions. Not only do ants use floral nectar, but it appears that some floral nectars contain compounds that are especially attractive to ants.