A class of neuroD-related basic helix-loop-helix transcription factors expressed in developing central nervous system in zebrafish

Neuronal basic helix-loop-helix (bHLH) transcription factors such as neuroD and neurogenin have been shown to play important roles in neuronal development. In the present study, several distinct bHLH DNA fragments were isolated from the zebrafish genomic DNA by a pair of degenerate polymerase chain reaction (PCR) primers deduced from the conserved bHLH domains of neuroD and neurogenins. Based on the bHLH fragments, three complete neuroD-related cDNA clones, including complete coding regions, ndr1a, ndr1b, and ndr2 (ndr for neuroD related), were isolated and assembled by 5' and 3' rapid amplification of cDNA ends (RACE). A phylogenetic analysis indicated the presence of four groups of neuroD-related genes in the neuroD subfamily in vertebrates: neuroD, ndr1a/ndr1b/MATH-2, ndr2/NDRF, and neuroM/MATH3. Expression of the newly isolated neuroD-related genes was examined by reverse transcriptase (RT)-PCR and whole-mount in situ hybridization. Unlike neuroD, which was expressed broadly in primary neurons during early zebrafish development starting from 10 h postfertilization (hpf), expression of ndr1a and ndr1b started relatively late (around 22 hpf) and was restricted to the olfactory system: olfactory bulbs in the telecephalon (ndr1a and ndr1b) and olfactory organs (ndr1b) starting around 22 hpf. Although a faint ndr2 mRNA signal was detected by RT-PCR in early embryos, no ndr2 mRNA was detected by whole-mount in situ hybridization in embryos up to 72 hpf, suggesting that it is expressed rather late. Our observations suggest that the two novel neuroD-related genes, ndr1a and ndr1b, are involved in the development of the olfactory system and perhaps contribute to its functional complexity.

Molecular cloning and biochemical characterization of a novel anthocyanin 5-O-glucosyltransferase by mRNA differential display for plant forms regarding anthocyanin

UDP-glucose: anthocyanin 5-O-glucosyltransferase (5-GT) is responsible for the modification of anthocyanins to more stable molecules in complexes for co-pigmentation, supposedly resulting in a purple hue. The cDNA encoding 5-GT was isolated by a differential display applied to two different forms of anthocyanin production in Perilla frutescens var. crispa. Differential display was carried out for mRNA from the leaves of reddish-purple and green forms of P. frutescens, resulting in the isolation of five cDNA clones predominantly expressed in the red form. The cDNA encoded a polypeptide of 460 amino acids, exhibiting a low homology with the sequences of several glucosyltransferases including UDP-glucose: anthocyanidin 3-O-glucosyltransferase. By using this cDNA as the probe, we also isolated a homologous cDNA clone from a petal cDNA library of Verbena hybrida. To identify the biochemical function of the encoded proteins, these cDNAs were expressed in Saccharomyces cerevisiae cells. The recombinant proteins in the yeast extracts catalyzed the conversion of anthocyanidin 3-O-glucosides into the corresponding anthocyanidin 3,5-di-O-glucosides using UDP-glucose as a cofactor, indicating the identity of the cDNAs encoding 5-GT. Several biochemical properties (optimum pH, Km values, and sensitivity to inhibitors) were similar to those reported previously for 5-GTs. Southern blot analysis indicated the presence of two copies of 5-GT genes in the genome of both red and green forms of P. frutescens. The mRNA accumulation of the 5-GT gene was detected in the leaves of the red form but not in those of the green form and was induced by illumination of light, as observed for other structural genes for anthocyanin biosynthesis in P. frutescens.

Direct evidence for anthocyanidin synthase as a 2-oxoglutarate-dependent oxygenase: molecular cloning and functional expression of cDNA from a red forma of Perilla frutescens

Anthocyanidin synthase (ANS), an enzyme of the biosynthetic pathway to anthocyanin, has been postulated to catalyze the reaction(s) from the colorless leucoanthocyanidins to the colored anthocyanidins. Although cDNAs have been isolated that encode putative ANS, which exhibits significant similarities in amino acid sequence with members of a family of 2-oxoglutarate-dependent oxygenases, no biochemical evidence has been presented which identifies the actual reaction that is catalyzed by ANS. Here we show that anthocyanidins are formed in vitro through 2-oxoglutarate-dependent oxidation of leucoanthocyanidins catalyzed by the recombinant ANS and subsequent acid treatment. A cDNA encoding ANS was isolated from red and green formas of Perilla frutescens by differential display of mRNA. Recombinant ANS tagged with maltose-binding-protein (MBP) was purified, and the formation of anthocyanidins from leucoanthocyanidins was detected by the ANS-catalyzed reaction in the presence of ferrous ion, 2-oxoglutarate and ascorbate, being followed by acidification with HCI. Equimolar stoichiometry was confirmed for anthocyanidin formation and liberation of CO2 from 2-oxoglutarate. The presumptive two-copy gene of ANS was expressed in leaves and stems of the red forma of P. frutescens but not in the green forma plant. This corresponds to the accumulation pattern of anthocyanin. The mechanism of the reaction catalyzed by ANS is discussed in relation to the molecular evolution of a family of 2-oxoglutarate-dependent oxygenases.

Fast skeletal muscle-specific expression of a zebrafish myosin light chain 2 gene and characterization of its promoter by direct injection into skeletal muscle

A zebrafish myosin light chain 2 cDNA clone was isolated and characterized. Sequence analysis of the clone revealed a high homology with the mammalian and avian genes encoding the fast skeletal muscle isoform, MLC2f. In situ hybridization and Northern blot hybridization analyses indicated that the zebrafish MLC2f mRNA is expressed exclusively in the fast skeletal muscle. Ontogenetically, the MLC2f mRNA appears around 16 hours postfertilization (hpf) in the first few well-formed anterior somites. At later stages, the MLC2f mRNA can also be detected in fin buds, eye muscles, and jaw muscles. To develop a useful model system for analyzing muscle gene regulation, the promoter of the zebrafish MLC2f gene was isolated and linked to the chloramphenicol acetyltransferase (CAT) reporter gene. The MLC2f/CAT chimeric constructs were analyzed by direct injection into the zebrafish skeletal muscle, and significant CAT activity was observed; in contrast, little or no CAT activity was generated from a similarly injected prolactin gene promoter/CAT gene construct. Within the 1 kb of the MLC2f promoter region, several MEF2-binding sites and E-boxes were identified, suggesting that MLC2f can be regulated by muscle transcription factors MEF2 and myogenic bHLH proteins. A 5' deletion analysis indicated that the proximal 79 nucleotides from the transcription start site, which contains a single MEF2-binding site, is sufficient to drive a high level of CAT activity in injected muscle. Internal deletion of the MEF2 element in the -79-bp construct caused an 80% decrease in CAT activity, whereas internal deletion of the same MEF2 element in a -1044-bp construct had no effect on induced CAT activity. These observations suggest that an MEF2 element is important to activate the MLC2f gene in muscle cells, and the effect of loss of the proximal MEF2 element can be compensated for by the presence of the upstream MEF2 elements. This study also demonstrated that direct injection of DNA into skeletal muscle is a valid and valuable approach to analyze muscle gene promoters in the zebrafish.

Expression of zebrafish bHLH genes ngn1 and nrd defines distinct stages of neural differentiation

Two zebrafish bHLH genes, neurogenin-related gene I (ngn1) and neuroD (nrd), have been isolated. ngn1 expression is initiated at the end of gastrulation in the neural plate and defines broad domains of cells that probably possess an ability to develop as neurons. This finding suggests that ngn1 may play a role during determination of cell fate in neuroblasts. ngn1 and pax-b are expressed in a mutually exclusive manner. nrd expression follows that of ngn1 in restricted populations of cells selected from ngn1-positive clusters of cells. The earliest nrd-positive cells in the brain and the trunk are a subset of the primary neurons. ngn1 is not expressed in the eye. Here, nrd transcription is activated at 25 hours postfertilization in the ventral retina. Expression of islet-1 occurs in nrd-positive cells after expression of nrd, and the expression of the two genes partially overlaps in time. These observations suggest that during eye development nrd expression may follow expression of some other neurodetermination gene(s). This supports the idea that expression of nrd is a necessary step leading toward overt neuronal differentiation.

Decreases in brain glial fibrillary acidic protein (GFAP) are associated with increased serum corticosterone following inhalation exposure to toluene

Toluene and other neurotoxicants can cause both increases and decreases in the concentration of GFAP in the brain. While increased GFAP concentration is widely regarded as evidence for reactive gliosis, toxicant-induced decreases in GFAP have received less attention. In order to identify conditions under which inhalation exposure to toluene results in decreased GFAP concentration, rats were subjected to repeated inhalation of toluene for up to 7 days. Adult male F344 rats received inhalation exposure to air or to 1000 ppm toluene, 6 hr/day, for 3 or 7 days. This toluene exposure replicated the previously-observed decreases in GFAP in the thalamus. Serum Corticosterone was significantly elevated in the same rats that exhibited decreases in brain GFAP concentration. These results show that decreases in brain GFAP might be a consequence of disruption of the hypothalamic-pituitary-adrenal axis and/or hormonal homeostasis. Changes in GFAP and in Cort were not accompanied by a change in body weight. More research is needed to firmly establish cause and effect between increased serum glucocorticoid levels and GFAP decreases following toluene inhalation and to determine whether these decreases indicate toxicity or adaptive changes.

Finite temporal measurements of the statistical characteristics of the atmospheric coherence length

Based on the theory of stationary random processes, the probability density function of the atmospheric coherence length measured in a finite time period is derived analytically and verified experimentally. An iteration method is proposed to obtain Fried's coherence length within a finite time measurement.

Phase-compensation experiment with a 37-element adaptive optics system

An experimental study on phase compensation for turbulent effects with a 37-element adaptive optics system is performed in both a simulated turbulence cell and in a real atmosphere. The experimental results demonstrate that the compensated Strehl ratio S(0), which is influenced mainly by the deformable-mirror fitting error, has a functional form S(0) = exp[-kappa(d/r(0))(5/3)], where r(0) is Fried's coherence length and d is the average interval of the actuators on the deformable mirror. The fitting parameter kappa is 0.45. Numerical simulations are also performed with the experimental parameters. The numerical results are in agreement with data obtained in the experiment, which shows that the direct-tilt phase-reconstruction method used in our four-dimensional simulation code is reasonable.

A new splicing variant of a type III POU gene from zebrafish encodes a POU protein with a distinct C-terminal

A zebrafish POU protein cDNA clone was isolated and sequenced. It appears to be a novel splicing variant of the previously reported zebrafish POU gene zp-12. There are four splicing variants and at least three of them lead to different C-terminal amino acid sequences. The four splicing variants are differentially regulated during development, indicating that they may be functionally diversified.

The skin-type antifreeze protein gene intron of the winter flounder is a ubiquitous enhancer lacking a functional C/EBPalpha binding motif

The winter flounder antifreeze protein (AFP) intron contains a liver-specific enhancer (Element B) which was shown earlier to bind CCAAT/enhancer binding protein (C/EBP)alpha. In contrast, as demonstrated in the present studies, the intron of the skin-type AFP gene acted as a ubiquitous enhancer and contained a TA insertion at similar region to Element B (Element S) which destroyed its interaction with C/EBPalpha. Furthermore, a TA insertion of Element B by site-directed mutagenesis decreased its liver enhancer activity. The presence or absence of C/EBPalpha binding motifs in Element B and Element S, respectively, may provide a mechanism for their differential expression.

[Investigation for polymorphism of ALDH2 exon12 in several Asian areas]

Mitochondrial aldehyde dehydrogenase (ALDH2) shows genetic polymorphism (Glu487Lys substitution) among Mongoloid populations, and the substitution is responsible for flushing symptom after alcohol intake. Recently, new ALDH2 alleles (ALDH2*3 and ALDH2*2Taiwan) in exon12 were reported in North American Indians and in Chinese from Taiwan by Novoradskey et al (1995). In the present study, we investigated the new allelic variants in exon12 for the five different ethnic groups (Mongolian, North Chinese, South Chinese, Myanmar, Japanese) by using PCR-SSCP and PCR-direct sequencing. Also, Glu 487 Lys substitution was analyzed to obtain additional information on gene geography of ALDH2 alleles in Asia reported so far. No new variants were found in the five population groups, but ALDH2*2 allele showed different frequencies among these groups. Especially, the frequencies of ALDH2*2 in Myanmer (0.02) and Mongolian (0.05) were significantly lower than other populations.

Vertebrate genome evolution and the zebrafish gene map

In chordate phylogeny, changes in the nervous system, jaws, and appendages transformed meek filter feeders into fearsome predators. Gene duplication is thought to promote such innovation. Vertebrate ancestors probably had single copies of genes now found in multiple copies in vertebrates and gene maps suggest that this occurred by polyploidization. It has been suggested that one genome duplication event occurred before, and one after the divergence of ray-finned and lobe-finned fishes. Holland et al., however, have argued that because various vertebrates have several HOX clusters, two rounds of duplication occurred before the origin of jawed fishes. Such gene-number data, however, do not distinguish between tandem duplications and polyploidization events, nor whether independent duplications occurred in different lineages. To investigate these matters, we mapped 144 zebrafish genes and compared the resulting map with mammalian maps. Comparison revealed large conserved chromosome segments. Because duplicated chromosome segments in zebrafish often correspond with specific chromosome segments in mammals, it is likely that two polyploidization events occurred prior to the divergence of fish and mammal lineages. This zebrafish gene map will facilitate molecular identification of mutated zebrafish genes, which can suggest functions for human genes known only by sequence.

Transgenic Arabidopsis lines expressing gene VI from cauliflower mosaic virus variants exhibit a range of symptom-like phenotypes and accumulate inclusion bodies

Gene VI of cauliflower mosaic virus (CaMV) is an important determinant of symptom expression during infection. We have constructed a series of transgenic Arabidopsis lines that express gene VI protein (P6) from two CaMV isolates (Bari-1 and Cabb B-JI) that cause mild and severe symptoms, respectively, in Arabidopsis, and from a recombinant virus (Baji-31) with a hybrid gene VI that causes very severe symptoms. From 41 transgenic lines analyzed, 17 showed symptom-like phenotypes that ranged from mild vein chlorosis to severe chlorosis and stunting. P6 levels in transgenic lines varied from undetectable in the lowest expressors to levels greater than those in CaMV-infected plants. There was a strong correlation between phenotype severity and the level of P6, and with the gene VI origin in the order, Baji-31 > B-JI > Bari-1. This was similar to symptom severity in Arabidopsis infected with the respective CaMV variant. We also found that transgenic P6 accumulated in inclusion bodies that were similar to those found in infected plants but lacking virions. We conclude that expression of P6, in the absence of virus replication, elicits a subset of the host symptom responses normally observed during infection and that the level, sequence, and possibly the form of P6 are important in potentiating the process.

Cloning and molecular analysis of structural genes involved in anthocyanin biosynthesis and expressed in a forma-specific manner in Perilla frutescens

Two cultivars of Perilla frutescens, red and green formas are known to differ in anthocyanin accumulation in leaves and stems. cDNA clones encoding the enzymes involved in anthocyanin biosynthesis, chalcone synthase (CHS), flavanone 3-hydroxylase (F3H), dihydroflavonol 4-reductase (DFR), and UDP glucose: flavonoid 3-O-glucosyltransferase (3GT), were isolated from cDNA libraries derived from the leaves of a red forma of P. frutescens by screening with partial fragments amplified by means of polymerase chain reaction (PCR) and heterologous cDNAs as probes. The deduced amino acid sequences of these four genes exhibited 40-90% identity with those reported for the corresponding gene from other unrelated species. Southern blot analysis for these genes and two other structural genes, the leucoanthocyanidin dioxygenase (LDOX, anthocyanidin synthase) and anthocyanin acyltransferase (AAT) genes, indicated that each gene comprises a small multi-gene family. More than three copies of the CHS gene are present, two copies of the other genes being present. The expression of five genes, the exception being the CHS gene, was detected only in red leaves of the red forma of P. frutescens, i.e. not in green leaves of the green forma plant. The CHS gene was expressed in both red and green leaves, but 10-fold more in red leaves than in green leaves. These results suggest that the expression of all structural genes examined is coordinately regulated in a forma-specific manner. Under weak-light conditions, the accumulation of both anthocyanin and mRNAs of biosynthetic enzymes was lower in leaves of the red forma. High-intensity white light coordinately induced the accumulation of transcripts of all six genes examined in the mature leaves of red P. frutescens.

Rapid identification and isolation of zebrafish cDNA clones

A fast and economical approach, referred to as cDNA clone tagging, was adapted to identify and isolate zebrafish cDNA clones. The basic approach was to partially sequence the coding region of size selected cDNA clones and the partial sequences were then used as tags for identifying the clones through homology search. To benefit maximally from the tagging approach, two cDNA libraries, derived from embryonic and adult fish poly(A)+ RNAs, respectively, were constructed by unidirectional cloning; conceptually, they have the potential to represent all expressed zebrafish genes. A total of 1084 clones were sequenced from the two libraries, and 511 clones were identified, based on sequence homology. These identified clones were derived from at least 261 genes, encoding 48 translational machinery proteins, 47 cytosolic proteins, 43 cytoskeletal proteins, 41 nuclear proteins, 32 membrane proteins, 22 secreted proteins, 20 mitochondrial proteins and 8 proteins with an unknown location. Of the 261 distinct cDNA clones identified, 254 were isolated for the first time in the zebrafish. These tagged cDNA clones, identified and unidentified, provide rich resources for developmental analysis as well as mapping of zebrafish genome. The long-term objective of this study is to establish a tagged zebrafish gene library that can be accessed both by hybridization screening against the plasmid DNAs and by electronic screening using the sequence information.

Simultaneous determination of the aerosol complex index of refraction and size distribution from scattering measurements of polarized light

In this study we attempt to determine the aerosol complex index of refraction and size distribution from scattering measurements of polarized light. We illustrate that the scattering matrix elements M(2)(100 degrees ) and D(21) (150 degrees ) can be selected as an optimum set of matrix elements for determination of the complex index of refraction. We also illustrate that errors increase if we include insensitive scattering matrix elements in the determination of the complex index of refraction. A method is developed for the simultaneous determination of the complex index of refraction and the size distribution. In our method, we selected two sets of matrix elements, M (2) (100 degrees ) and D (21) (150 degrees ), for the determination of the complex index of refraction and others, which are much less sensitive to the complex index of refraction than M(2) (100 degrees ) and D(21) (150 degrees ), for the determination of the size distribution, based on their sensitivity analyses. A modified inversion library algorithm is adopted to solve the coupled system. Numerical experiments show that both the complex index of refraction and the size distribution can be determined with reasonable accuracy when we apply our method to scattering measurements of polarized light.

[Enhanced emission spectra of Yb, Eu, Y and Sm HCLS with high current microsecond pulsed supply]

The emission spectra of Yb, Eu, Y, Sm hollow cathode lamps have been investigated with a high current microsecond pulsed (HCMP) supply developed in our laboratory. Both atomic and ionic emission lines of interest of these rare earth elements are enhanced by tens to tens of thousand times in HCMP mode compared to DC mode. Effects of parameters of the supply on emission intensities are surveyed. HCMP HCLs may be used as an economic and convenient excitation source for atomic/ionic fluorescence spectrometric analysis.

[Determination of Ni, Al, Mn and Si in copper based alloy by high current and microsecond pulsed glow discharge optical emission spectrometry]

The determination of Ni, Al, Mn and Si in copper based alloy by high current and microsecond pulsed (HCMSP) glow discharge optical emission spectrometry (GD-OES) has been reported. With the laboratory built experiment set-up, the factors effecting analytical performance have been studied. The results of sample analysis are in good agreements with the recommendation values, and the stansard deviation for six determinations were 2.66% for Ni, 2.17% for Mn, 6.02% for Si, 1.00% for Al respectively.

Effect of chelation with meso-dimercaptosuccinic acid (DMSA) before and after the appearance of lead-induced neurotoxicity in the rat

This paper examines whether a chelating agent (DMSA) can prevent and reverse the effects of lead (Pb) as evidenced by changes in brain glial fibrillary acidic protein (GFAP) concentration and in the habituation pattern of rearing behavior. Male F344 rats (42 days old) received Pb acetate at 150 or 2000 ppm as Pb in their drinking water for 21 days and returned to regular water for another 21 days to observe recovery. Blood Pb (BPb) concentration rose to 37 and 82 microg/dl for 150 and 2000 ppm, respectively. Rats exposed to 150 ppm Pb exhibited changes in GFAP concentration and behavioral hyperactivity, when placed in an unfamiliar cage. The 2000 ppm Pb exposure caused greater changes in GFAP, but behavioral hyperactivity appeared only postexposure, when BPb was declining. Chelation (DMSA, 50 mg/kg po, 3 times/week for 21 days) decreased the BPb concentration, and prevented and reversed the Pb-induced changes in GFAP and rearing, but not in body weight. Administration of DMSA by itself for 21 days caused no untoward effects in brain GFAP, behavior, or body weight. Concurrent administration of DMSA and Pb resulted in no evidence of additive toxicity. Results indicate that: (1) A brief behavioral test of habituation is a sensitive index of neurotoxicity and chelating therapy; (2) Pb-induced hyperactivity depends upon BPb concentration regardless of whether activity is measured during or after exposure; (3) repeated treatment with DMSA is effective in reducing Pb neurotoxicity; (4) there was no evidence that DMSA enhanced the absorption of Pb. The finding that DMSA administered late in exposure can hasten the recovery of toxic signs suggests that extracellular Pb continues to play a significant role even after toxic signs have appeared.

[Progress in determination of rare earths by atomic/ionic fluorescence spectrometry]

The progress of determination of rare earths by atomic/ionic fluorescence spectrometry is reviewed. The experimental systems and the analytical characteristics of the technique are briefly discussed, and its applications are illustrated in detail. The research trends are predicted as well. The systems with appropriate combinations of excitation sources and atomization/ionization cells are well proved to increase analytical sensitivity and minimize interferences. For the excitation soures, hollow cathode lamp has been proved to be economic and practical, although pulsed dye laser has been intensively investigated. The inductively oupled plasma is a preferable atomization/ionization cell. The atomic/ionic fluorescene spectrometry is one of effective techniques for the determination of rare earths mainly due to its low spectral interference and wide linear dynamic range.

Optosensor for cinchona alkaloids with C18 silica gel as a substrate

A flow-through optosensor for cinchona alkaloids with C18 silica gel as a substrate is proposed. The sensor is developed in conjunction with a flow-injection analysis system and is based on the retention of the cinchona alkaloids on a C18 column and the enhancement of their fluorescence. The analytical performance characteristics of the proposed sensor for the detection and quantification of these alkaloids were as follows: the detection limits of quinine, cinchonine, quinidine and cinchonidine were 2.3, 31.6, 2.3 and 31.6 ng ml-1, respectively, with relative standard deviations of 0.9% for quinine and quinidine (20 ng ml-1, n = 7) and 1.1% for cinchonine and cinchonidine (4.0 micrograms ml-1, n =7), respectively. Most of the common species did not interfere. The recommended method has been successfully tested for determination of quinine in pharmaceutical preparations and soft drinks.

An abundant zebrafish cDNA clone encodes a ras-like protein which is expressed ubiquitously

An abundant clone from a zebrafish embryonic cDNA library was identified and sequenced. It encodes a ras-like protein, being 94-95% identical to vertebrate Ran, ras-related nuclear protein. The zebrafish Ran mRNA is expressed in all tissues examined and throughout embryogenesis; therefore, it is likely that the Ran protein functions in all types of cells.

[Clinical significance of c-erbB2 oncoprotein expression in stomach carcinoma]

This paper reports a study of the c-erbB2 oncoprotein (by immunohistochemical method) in 97 gastric carcinoma resected at Shanghai Cancer Hospital in 1991. In 30 out of the 97 cases (30.9%) c-erbB2 was positive and its expression was higher among patients with lymph node metastasis (P < 0.05). Univariate and multivariate analyses indicated that c-erbB2 expression betokened poor prognosis.

Lead-induced alterations of glial fibrillary acidic protein (GFAP) in the developing rat brain

The developing nervous system is preferentially vulnerable to lead exposure with alterations in neuronal and glial cells of the brain. The present study examined early lead-induced alterations in the developing astrocyte population by examination of the developmentally regulated astrocyte specific protein, glial fibrillary acidic protein (GFAP). A developmental profile (Postnatal Day (PND) 6, 9, 12, 15, 20, and 25) for GFAP mRNA was generated for the cortex and hippocampus of developing Long-Evans hooded male rats under various lead exposure conditions: (1) prenatal (Gestational Day 13 to birth), (2) postnatal (Postnatal Day 1 to Postnatal Day 20), or (3) perinatal (Gestational Day 13 to Postnatal Day 20) exposure to lead acetate (0.2% in the drinking water of the dam). Control GFAP mRNA levels displayed a developmentally regulated profile of expression. In the cortex this was characterized by a transient elevation in peak level between PND 9 and PND 15 followed by a decline to within adult levels by PND 25. Under all lead acetate exposure conditions, the cortex showed an increase in the peak level of expression and extended the time of elevation of GFAP mRNA until PND 20. Levels of GFAP were elevated at PND 60 but not as early as PND 28. In the control hippocampus, levels of GFAP mRNA gradually increased until PND 20 followed by a sharp decline at PND 25. Postnatal and perinatal lead exposure followed a similar pattern; however, levels declined earlier at PND 20. Following prenatal lead exposure, levels of GFAP mRNA showed an earlier peak at PND 12 and a decrease as early as PND 15. By PND 60 protein level for GFAP was elevated in the postnatal lead exposure group only. As demonstrated by GFAP immunoreactivity, these lead-induced elevations were not associated with astrocyte hypertrophy. Following a physical injury in the cortex, astrocyte reactivity was similar between lead-exposed and control rats. These data suggest an alteration in the timing of astrocyte differentiation and maturation in the brain following developmental lead exposure.

[A study on AIDS-related knowledge, attitude and behavior in servicemen in China]

AIDS-related knowledge, attitude and behavior were studied in 1,058 servicemen in China with self-administered and anonymous questionnaires. Results showed 76.7% to 89.5% of the servicemen surveyed knew correctly the risk of AIDS and its route of transmission, but only 8.5% of them answered all the questions listed in the questionnaire correctly. Source of their knowledge about AIDS was mainly from newspapers, magazines and extracurricular books. Most of them thought they could have very little, or no chance to contract the illness. There were 74.0% of the servicemen eager to get knowledge about AIDS and 83.2% would like to accept relevant testing. And, 80.2% of them answered that they could put their behavior under control, or change their unhealthy one to prevent from the illness. It indicated that comprehensive and correct publicity and education could play an active role in the prevention of HIV infection.

Intraoperative transesophageal echocardiography using high-resolution biplane 7.5 MHz probes with continuous-wave Doppler capability in infants and children with tetralogy of Fallot

This study reports the role of biplane transesophageal echocardiography in monitoring surgical repairs of tetralogy of Fallot. In our patients, 3 repairs were revised based on transesophageal echocardiography and continuous-wave Doppler results, and intraoperative management was altered in 2 others.

Skin antifreeze protein genes of the winter flounder, Pleuronectes americanus, encode distinct and active polypeptides without the secretory signal and prosequences

Distinct antifreeze polypeptides (AFP) were isolated from the skin of the winter flounder, Pleuronectes americanus, by gel filtration and reverse phase high performance liquid chromatography. In parallel, several cDNA clones were isolated from a skin cDNA library using a liver AFP cDNA probe. Both protein and DNA sequence analyses indicate that flounder skin contains several distinct but homologous alanine-rich AFPs. Although the skin type AFPs contain 11 similar amino acid repeats found in the secretory liver type AFPs, the skin type AFPs are mature polypeptides lacking both the signal and prosequences, indicating that they may function intracellularly. The skin type AFP is significantly less active in thermal hysteretic activity than the liver type AFP. Genomic Southern analysis indicates that like the liver type AFP genes, there are multiple copies (30-40 copies) of skin type AFP. Although the liver type AFP genes are specifically expressed in the liver and to a lesser extent in intestine, the skin type AFP genes are expressed in all tissues examined including the liver and abundantly in exterior tissues, i.e. skin, scales, fin, and gills, suggesting an important protecting role in these exterior tissues.

Trimethyl lead neurotoxicity in the rat: changes in glial fibrillary acidic protein (GFAP)

The literature on the toxicology of lead provides little evidence of the neurotoxicity of organic lead compounds. Toxicant-induced changes in the concentration of glial fibrillary acidic protein (GFAP) in the brain may help clarify at which stage of neurotoxicity astrocytes are affected and whether GFAP may provide an index of toxicity. Male F344 rats (> 42 days old) were exposed to 0 (control), 8 or 16 ppm lead as trimethyl lead (TMPb) in drinking water for up to 14 days. Weight Gain was significantly reduced in both exposed groups. Control rats had the expected brain regional pattern of GFAP concentration with the highest in the hippocampus and cerebellum and lowest in the cerebral cortex. The hippocampus was the region very sensitive to TMPb, with increased GFAP in rats exposed to 8 and 16 ppm TMPb with decreases in GFAP in rats exposed to 8 and 16 ppm TMPb for 14 days. There was a significant time-response in rats exposed to 8 ppm TMPb with decreases in GFAP on day 7 and increases on day 14. A hypothesis concerning this biphasic change in GFAP concentrations is discussed. The results indicate that GFAP may be used to indicate the role of the astrocyte in the neurotoxicity of TMPb. GFAP concentration, as biomarker of TMPb effect, was as sensitive to TMPb as body weight and thus may provide a marker of neurotoxicity.

Molecular heterogeneity among primary motoneurons and within myotomes revealed by the differential mRNA expression of novel islet-1 homologs in embryonic zebrafish

Zebrafish embryos have three or four identifiable primary motoneurons per hemisegment. We previously reported that, while several ventral cells initially express the zebrafish Islet-1 (Isl-1) gene, a member of the LIM/homeobox gene family, the expression of this gene becomes restricted to a single or a pair of cells slightly anterior to each segment border by 16 hr after fertilization. Double staining by in situ hybridization and immunohistochemistry strongly suggested that these cells were mainly rostral primary motoneurons. Here, we have isolated two novel zebrafish cDNA clones for more Isl-1 family genes, termed zfIsl-2 and zfIsl-3. zfIsl-2 mRNA starts to be expressed in the ventral midsegmental cells per hemisegment around 15 hr. Double labeling experiments have shown that these midsegmental cells are the caudal primary motoneuron (CaP) and its variant equivalence pair. Our results revealed the heterogeneity in the expressed genes among primary motoneurons before the fates of the primary motoneurons are irreversibly determined, and further suggest the involvement of the Isl-1 and zfIsl-2 genes in the determination of cellular identities by primary motoneurons in embryonic zebrafish. zfIsl-3 mRNA is not expressed in motoneurons but is expressed at 17 hr, mainly in the ventral myotomes. This suggests that zfIsl-3 may be involved in the regional specification of the myotome and also in target recognition by CaP. zfIsl-2 is also expressed throughout the developing eye and tectal region of the midbrain, the target for the retinal axons. In the ventral spinal cord of the spadetail mutant embryo, which has defects in the somites, the cells expressing zfIsl-2 mRNA significantly decreased in number in contrast to the increase in cells expressing Isl-1 mRNA, suggesting the influence of the somites on the expression of both genes.

A comparison of the effects of the propofol versus midazolam during total intravenous anesthesia for gynecological surgery procedures

The effects of propofol and midazolam as an intravenous anesthetic were compared in 40 ASA I-II patients undergoing gynecological surgery during total intravenous anesthesia (TIVA). They were divided into propofol group (P n = 20) and midazolam group (M n = 20) randomly. The anesthesia was designed for each group respectively. Here, we discuss the experimental method and the results, which indicate that propofol is not only an effective anesthetic but also has more rapid and head-clear recovery properties than midazolam.

[Clinical research of muscular relaxation induced by alcuronium and pancuronium]

The clinical experiment was designed for observing effect of muscular relaxation induced by alcuronium and pancuronium. 40 patients were randomly divided into alcuronium group (A) and Pancuronium group (P). A group and P group were redivided into A1,A2 groups and P1,P2 groups according to differences of the initial doses of muscle relaxants. The results of neuromuscular monitoring indicate that onset time and main-tenance time of 0.3 mg/kg alcuronium were respectively 2.4 min and 63 min; 0.1 mg/kg pancuronium were 2.7 min and 70 min. The initial doses mentioned above are suitable to intubation of anesthesia and meet surgical need for muscular relaxation. The changes of MAP,HR,blood kalium and natrium were not evident in statistical significance before and after administration of relaxants.

Expression of the antifreeze protein gene in transgenic goldfish (Carassius auratus) and its implication in cold adaptation

Ocean pout (Macrozoarces americanus) antifreeze protein (AFP) genes (approximately 10(6) copies) were microinjected into the oocytes of goldfish (Carassius auratus). Out of a total of 303 oocytes injected, 235 (77.6%) were normally fertilized after in vitro maturation and insemination, and 136 (57.9%) of the fertilized eggs were hatched. Dot blot analysis of genomic DNA from 2-month-old fish indicated that 30 of the fish (22%) were positive for the AFP transgene. The numbers of integrated AFP genes ranged from a single copy to multiple copies per cell. Two P1 male founders, Y45 and GV16, were crossed separately with a control female, and the inheritance of the AFP transgene was analyzed. Results from Southern blotting and polymerase chain reaction were found to be 7% (5 out of 82) and 58.8% (20 out of 34), respectively, indicating that these two founders are mosaic. The percentage of positive F2 generated from Y45F1 crossed with a control female was 56%, consistent with a Mendelian inheritance. Mature AFP detected by immunoblotting was expressed in both F1 and F2 offspring. These studies indicate that the antifreeze protein gene is successfully transferred and expressed in goldfish. Transgenic goldfish are significantly more cold tolerant than controls when challenged with low temperatures. These studies suggest that the AFP gene may have application in providing cold tolerance in addition to freeze resistance for a variety of fish species.

Several splicing variants of isl-1 like genes in the chinook salmon (Oncorhynchus tschawytscha) encode truncated transcription factors containing a complete LIM domain

Several novel cDNA clones have been isolated from a chinook salmon pituitary cDNA library. Sequence analysis of these clones indicates that they are closely related to the rat LIM domain homeobox gene, isl-1. Due to differential splicing, several of the clones encode truncated polypeptides containing a complete copy of the LIM domain without the homeodomain and C-terminal activation domain. The roles of these truncated polypeptides are discussed.

Presence of isl-1-related LIM domain homeobox genes in teleost and their similar patterns of expression in brain and spinal cord

Three novel LIM domain homeobox cDNAs encoding proteins structurally related to the Isl-1 protein were isolated from a chinook salmon pituitary cDNA library. Southern blot analysis of genomic DNA indicate that they are derived from three distinct genes, designated as isl-2a, isl-2b, and isl-3 genes. Nucleotide sequence analysis of reverse transcriptase-polymerase chain reaction amplified products reveal that the isl gene family contains two members (a and b) each of both isl-1 and isl-2 genes, and one member of isl-3 gene in the two tetraploid salmonid species, chinook salmon and rainbow trout, and only one member each of isl-1, isl-2, and isl-3 genes in the diploid zebrafish. The expression of the three isl genes in the rainbow trout were studied by reverse transcriptase-polymerase chain reaction analysis of embryonic and adult RNAs, and by in situ hybridization analysis of 8-week-old hatchlings. The transcripts of all three genes could be detected as early as 4 weeks postfertilization (the eye stage) and increased dramatically in 5-week-old embryos. In the adult, the three isl mRNAs appear to be differentially distributed in various tissues. The level of isl-1 mRNA is generally higher than those of isl-2 and isl-3 mRNAs. In situ hybridization analysis indicates that the transcripts of all three genes are localized in subsets of neurons in the brain and spinal cord. In the retina, isl-1 mRNA could be found in both the ganglion and inner nuclear layers while isl-2 and isl-3 mRNAs could only be detected in the ganglion layer. High level of isl-1 mRNA could also be found in mid-gut and interrenal organ where endocrine cells are densely populated. Based on these observations, we speculate that the three structurally related isl genes may play similar roles in cell determination and differentiation in the developing nervous system.

The antifreeze protein genes of the winter flounder, Pleuronectus americanus, are differentially regulated in liver and non-liver tissues

The synthesis of winter flounder (Pleuronectus americanus) antifreeze protein (AFP) mRNAs in the liver is seasonally regulated by the pituitary gland. With the recent discovery that AFP mRNAs are also present in several non-liver tissues, the aim of the present investigation was to compare the regulatory mechanisms of AFP genes in liver and non-liver tissues. Northern blot analyses indicate that the level of liver AFP mRNA undergoes a several hundred fold difference between the winter and summer months, while AFP mRNAs from gills and kidneys exhibit only a modest 5-10 fold seasonal variation. As expected, the liver AFP mRNA in the hypophysectomized fish was increased by over 40 fold. However, no significant increase was observed for the non-liver AFP mRNAs upon hypophysectomy. These investigations suggest that AFP mRNAs in liver and non-liver tissues are differentially regulated.

Zinc and DNA binding properties of a novel LIM homeodomain protein Isl-2

LIM homeodomain proteins are a family of recently characterized proteins which contain, in addition to a homeodomain, two tandem repeats of conserved Cys-His motifs termed as LIM domains. We have recently isolated several clones from a chinook salmon pituitary cDNA library that encode two novel LIM homeodomain proteins, Isl-2 and Isl-3, which are structurally related to rat Isl-1. In the present study, we used the salmon Isl-2 to determine the role of LIM domains in DNA binding. Several glutathione S-transferase (GST) fusion proteins containing either full length Isl-2 or various portions of this protein were expressed in bacteria. Zinc blot analysis reveals that the LIM domains produced in bacteria are capable of binding zinc. Gel shift analysis indicates that all homeodomain-containing fusion proteins are able to bind to a TAAT target sequence while the fusion proteins containing only the LIM domain are not. In contrast to a previous observation that the LIM domains of rat Isl-1 have an inhibitory role in DNA binding, full length salmon Isl-2 containing both the LIM domains and a homeodomain can bind to a TAAT target sequence. To further examine the role of LIM domains in DNA binding, several GST fusion proteins were used to select specific target DNA sequences from a pool of randomly incorporated oligonucleotides. Specific target DNAs were selected by fusion proteins containing the homeodomain or the full length Isl-2, but not by LIM domain only fusion proteins, indicating that the LIM domain alone is not involved in DNA binding. The selected target DNAs were cloned and sequenced. They revealed two classes of consensus, C/TTAATG/TG/A and C/TTAAGTG, for both the homeodomain and full length Isl-2. The two classes of consensus competed with each other for binding to the homeodomain. The equilibrium dissociation constants for DNA binding, estimated by Scatchard analysis, were similar for the homeodomain and full length Isl-2.(ABSTRACT TRUNCATED AT 400 WORDS)

Bulk isolation and identification of fish genes by cDNA clone tagging

The fish has long been a popular research model for various disciplines in the life sciences, but its molecular biology remains largely unexplored, and the number of fish genes identified at present is still limited. To increase the repertoire of fish genes to facilitate further research, we have embarked on cDNA clone tagging studies in several teleosts. The basic procedure is partial sequencing of randomly selected cDNA clones by a single sequencing reaction to obtain nucleotide sequences of about 200 to 300 bp for each clone. These partial DNA sequences can be used as tags to identify fish homologous genes by searching for sequence similarity in DNA databases. By this method, we have sequenced a total of 265 clones from pituitary and liver cDNA libraries from five species of fish and identified 83 clones encoding 55 different genes. These 55 genes are described for the first time in their species, and 37 of them are described for the first time in fish. These preliminary data indicate that cDNA clone tagging is useful for rapidly increasing the number and availability of genes in teleosts. Several applications of these tagged random clones are discussed.

Isolation and characterization of somatolactin genes from two cold water marine teleosts, lumpfish (Cyclopterus lumpus) and halibut (Hippoglossus hippoglossus)

Somatolactin (SL) is a newly discovered pituitary hormone structurally related to both growth hormone and prolactin. We isolated the SL gene from two cold water marine teleosts, lumpfish (Cyclopterus lumpus) and halibut (Hippoglossus hippoglossus). The SL genes for lumpfish were isolated from a complementary DNA (cDNA) library by random gene tagging and sequencing. Two full-size clones of 1.2 (lfSL-6) and 1.6 (lfSL-9) kilobases (kb) were characterized. The SL genes for halibut were identified from its cDNA library using lumpfish SL gene as a probe. Two full-size SL clones of 1.1 and 1.6 kb were identified in halibut. All these clones encoded full-size SL (229 amino acids for lumpfish SL, 230 amino acids for halibut SL), including 7 cysteines and two and three potential glycosylation sites in halibut and lumpfish, respectively. The differences in length of these clones are attributed to their differences in 3' untranslated sequences. Although the halibut SL genes contain the consesus polyadenylation signal AATAAA, the lumpfish SL gene has the ATTAAA sequence in the larger clone (lfSL-9). None of the consensus or the alternative polyadenylation signals were found in the shorter clone (lfSL-6). Protein homology and DNA sequence alignments of SL genes from all five known marine fishes suggest that the SL gene sequence is highly conserved.

Development of an all-fish gene cassette for gene transfer in aquaculture

To develop an all-fish gene cassette suitable for gene transfer in aquaculture, the antifreeze protein (AFP) gene promoter from the ocean pout (Macrozoarces americanus) was analyzed for its ability to direct exogenous gene expression both in vitro and in vivo. The ocean pout AFP (opAFP) gene promoter fused to the bacterial chloramphenicol acetyltransferase (CAT) was functionally analyzed in two fish cell lines and in Japanese medaka embryos. The opAFP gene promoter was active in these systems, as demonstrated by the transient expression of CAT activity. These results suggest that the opAFP gene promoter is useful for many other gene transfer experiments. To facilitate use of the opAFP gene promoter as a common and versatile vehicle for fish gene transfers, an expression vector, opAFP-V, was constructed by linking the 2.1-kb opAFP gene promoter, the 63-bp opAFP gene 5' untranslated sequence, and the 1.2-kb opAFP gene 3' sequence by two unique restriction sites, Bg/II and HpaI, respectively. Thus, genes of interest can be inserted into either the Bg/II site or the HpaI site depending on the length of their 5' untranslated sequence. The complete DNA sequence of opAFP-V was determined to facilitate future detailed analysis of integration and expression of the transgene.

Phylogenetic specificity of prolactin gene expression with conservation of Pit-1 function

In mammals, the pituitary POU homeodomain protein, Pit-1, binds to proximal and distal 5'-flanking sequences of the PRL gene that dictate tissue-specific expression. These DNA sequences are highly conserved among mammals but are dramatically different from PRL 5' sequences in the teleost species, Oncorhynchus tschawytscha (chinook salmon). To analyze the molecular basis for pituitary-specific gene expression in a distantly related vertebrate, we transfected CAT reporter gene constructs containing 2.4 kilobases (kb) 5'-flanking sequence from the salmon PRL (sPRL) gene into various cell types. Expression of the sPRL gene was restricted to pituitary cells, but in rat pituitary GH4 cells levels of expression were at least 90-fold lower than those obtained with a -3 kb rat PRL (rPRL) construct. Conversely, in primary teleost pituitary cells, -2.4 kb sPRL/CAT was expressed at levels about 10-fold higher than -3 kb rPRL/CAT. To determine whether species-specific transactivation by Pit-1 was sufficient to explain these species differences in PRL gene expression, we isolated a cDNA clone encoding the salmon Pit-1 POU domain and constructed a rat Pit-1 expression vector that contained salmon Pit-1 POU domain sequences substituted in frame. The chimeric Pit-1 encoded 14 amino acids unique to salmon. Coexpression of rat Pit-1 with salmon or rat PRL/CAT in transfected HeLa cells resulted in specific and strikingly comparable levels of promoter activation. Moreover, the specificity and efficacy of the chimeric salmon/rat Pit-1 was similar to wild type rat Pit-1 in activating salmon and rat PRL/CAT.(ABSTRACT TRUNCATED AT 250 WORDS)

Functional analysis and temporal expression of promoter regions from fish antifreeze protein genes in transgenic Japanese medaka embryos

Several series of sequences that are upstream of the transcriptional start site of different types of fish AFP genes were fused to the bacterial CAT gene, and their transcriptional role was examined in a transient expression assay after microinjection into Japanese medaka (Oryzias latipes) embryos at the 1-4 cell stage. Our studies demonstrated that the AFP genes have functional promoter regions containing positive as well as negative regulatory regions, indicating that these genes could be regulated at multiple sites. We also observed a promoter-specific pattern of temporal expression. Typically, the CAT expression was low in the first 4 days of embryonic development or before the stage of body pigmentation, followed by a sharp increase. The high level was maintained until hatching (11-13 days after fertilization), by which time the activity decreased to a very low level.