Antisera to gamma-aminobutyric acid. I. Production and characterization using a new model system

Antisera to the amino acid gamma-aminobutyric acid (GABA) have been developed with the aim of immunohistochemical visualization of neurons that use it as a neurotransmitter. GABA bound to bovine serum albumin was the immunogen. The reactivities of the sera to GABA and a variety of structurally related compounds were tested by coupling these compounds to nitrocellulose paper activated with polylysine and glutaraldehyde and incubating the paper with the unlabeled antibody enzyme method, thus simulating immunohistochemistry of tissue sections. The antisera did not react with L-glutamate, L-aspartate, D-aspartate, glycine, taurine, L-glutamine, L-lysine, L-threonine, L-alanine, alpha-aminobutyrate, beta-aminobutyrate, putrescine, or delta-aminolevulinate. There was cross-reaction with gamma-amino-beta-hydroxybutyrate, 1-10%, and the homologues of GABA: beta-alanine, 1-10%, delta-aminovalerate, approximately 10%, and epsilon-amino-caproate, approximately 10%. The antisera reacted slightly with the dipeptide gamma-aminobutyrylleucine, but not carnosine or homocarnosine. Immunostaining of GABA was completely abolished by adsorption of the sera to GABA coupled to polyacrylamide beads by glutaraldehyde. The immunohistochemical model is simple, amino acids and peptides are bound in the same way as in aldehyde-fixed tissue and, in contrast to radioimmunoassay, it uses an immunohistochemical detection system. This method has enabled us to define the high specificity of anti-GABA sera and to use them in some novel ways. The model should prove useful in assessing the specificity of other antisera.     

A critical scanning electron microscope study of the scolex of Bothriocephalus acheilognathi Yamaguti, 1934, with a review of the taxonomic history of the genus Bothriocephalus parasitizing cyprinid fishes

Summary Bothriocephalus specimens from one Ctenopharyngodon idella (O+) were fixed using three different techniques and the scolex morphology was examined using scanning electron microscopy. The scolices were compared with figures of the five species of Bothriocephalus and one species of Schyzocotyle previously described from cyprinid fishes. The taxonomic history of the Bothriocephalus species parasitizing cyprinid fish is reviewed. It is concluded that there is only one Bothriocephalus species parasitizing cyprinid fishes, and that continued use should be made of the name B. acheilognathi Yamaguti, 1934. ac]19840326     

Differentiation induction in human breast tumor cells by okadaic acid and related inhibitors of protein phosphatases 1 and 2A.

Okadaic acid (OA), an inhibitor of protein phosphatases 1 and 2A, induces differentiation in human MCF-7, AU-565, and MB-231 breast tumor cells. In MCF-7 cells, OA elicited within 5 min an increase in the levels of a set of phosphorylated cellular proteins, within hours expression of the early response genes junB, c-jun, and c-fos, and within days manifestation of differentiation. Differentiation was also induced by two related protein phosphatase inhibitors, but not by an inactive OA derivative or by an inhibitor that penetrates epithelial cells poorly. These results indicate that OA and related agents can induce tumor breast cell differentiation, and this induction is correlated with their ability to inhibit PPH 1 and 2A.     

Patterns of sequence variation in the mitochondrial D-loop region of shrews

Direct sequencing of the mitochondrial displacement loop (D-loop) of shrews (genus Sorex) for the region between the tRNA(Pro) and the conserved sequence block-F revealed variable numbers of 79-bp tandem repeats. These repeats were found in all 19 individuals sequenced, representing three subspecies and one closely related species of the masked shrew group (Sorex cinereus cinereus, S. c. miscix, S. c. acadicus, and S. haydeni) and an outgroup, the pygmy shrew (S. hoyi). Each specimen also possessed an adjacent 76-bp imperfect copy of the tandem repeats. One individual was heteroplasmic for length variants consisting of five and seven copies of the 79-bp tandem repeat. The sequence of the repeats is conducive to the formation of secondary structure. A termination-associated sequence is present in each of the repeats and in a unique sequence region 5' to the tandem array as well. Mean genetic distance between the masked shrew taxa and the pygmy shrew was calculated separately for the unique sequence region, one of the tandem repeats, the imperfect repeat, and these three regions combined. The unique sequence region evolved more rapidly than the tandem repeats or the imperfect repeat. The small genetic distance between pairs of tandem repeats within an individual is consistent with a model of concerted evolution. Repeats are apparently duplicated and lost at a high rate, which tends to homogenize the tandem array. The rate of D- loop sequence divergence between the masked and pygmy shrews is estimated to be 15%-20%/Myr, the highest rate observed in D-loops of mammals. Rapid sequence evolution in shrews may be due either to their high metabolic rate and short generation time or to the presence of variable numbers of tandem repeats.      

大鼠胼胝体内神经肽Y免疫反应阳性纤维的发育

本实验用免疫组织化学ＡＢＣ法研究了大鼠胼胝体内神经肽Ｙ免疫反应阳性（ＮＰＹ－ＩＲ）纤维的生后发育。结果发现,许多ＮＰＹ－ＩＲ纤维在大鼠出生时便存在于胼胝体内。ＮＰＹ－ＩＲ胼胝体纤维的密度在生后１周内继续逐渐增高,在第２周内达到最高峰。之后,ＮＰＹ－ＩＲ胼胝体纤维的密度逐渐下降,至第３周末时接近成年时的水平,即仅有少量ＮＰＹ－ＩＲ纤维存在于胼胝体内。这些结果提示在大鼠早期生后发育过程中许多ＮＰＹ－ＩＲ胼胝体纤维是暂时性的,其作用可能与大脑皮质的机能发育有关。     

Characterisation of the external features ofSchistocephalus solidus (Müller, 1776) (Cestoda) from different geographical regions and an assessment of the status of the Baltic ringed sealPhoca hispida botnica (Gmelin) as a definitive host

A comparative study of some morphological (segment number, scolex morphology and biometry, length and weight) and biological (maturation in different hosts) features ofSchistocephalus solidus plerocercoids and adults from different geographical regions (Baltic Sea and the British Isles) was carried out. The length of the plerocercoids fromGasterosteus aculeatus was shown to be the variable that best correlated with segment number. A very clear bimodal distribution of segment numbers separated the majority of British and Baltic plerocercoids (British n=21, mean length 25.48, SD 5.63, range 14–34 mm; mean segment number 66.33, SD 8.68, range 51–86. Baltic n=30, mean length 33.23, SD 4.64, range 23–48 mm; mean segment number 117.27, SD 10.30, range 99–138). AdultS. solidus from the intestines of Baltic ringed sealsPhoca hispida botnica and from a Welsh cormorantPhalacrocorax carbo carbo were also compared, and a similar bimodal distribution of segment numbers was found (Baltic n=70, mean segment number 106.16, SD 10.60, range 77–136; Welsh n=98, mean segment number 73.13, SD 8.78, range 54–97). Neither the morphology nor measurements of the scolex from apical-view scanning electron microphotographs provided distinguishing features for taxonomic purposes. Of 580 adult worms from Baltic ringed seals only 2.9% were gravid, 2.1% from spring and 10.5% from autumn samples. By contrast, of 98 adults from the Welsh cormorant 46.7% were gravid. The proportion of gravid worms did not increase with increasing worm numbers in seals. Reasons for poor maturation are discussed. Plerocercoids of BritishS. solidus were fromleiurus (gymnurus) forms ofG. aculeatus, which were relatively small, whereas in the northern Baltic plerocercoids were fromsemiarmatus ortrachurus forms, which were larger. As segment number was definitively established during the growth of the plerocercoid in the stickleback, the hypothesis is proposed that segment number is a phenotypic variable related to stickleback length (size).     

Speed of Human Biological Form and Motion Processing

Recent work suggests that biological motion processing can begin within ~110 ms of stimulus onset, as indexed by the P1 component of the event-related potential (ERP). Here, we investigated whether modulation of the P1 component reflects configural processing alone, rather than the processing of both configuration and motion cues. A three-stimulus oddball task was employed to evaluate bottom-up processing of biological motion. Intact point-light walkers (PLWs) or scrambled PLWs served as distractor stimuli, whereas point-light displays of tool motion served as standard and target stimuli. In a second experiment, the same design was used, but the dynamic stimuli were replaced with static point-light displays. The first experiment revealed that dynamic PLWs elicited a larger P1 as compared to scrambled PLWs. A similar P1 increase was also observed for static PLWs in the second experiment, indicating that these stimuli were more salient than static, scrambled PLWs. These findings suggest that the visual system can rapidly extract global form information from static PLWs and that the observed P1 effect for dynamic PLWs is not dependent on the presence of motion cues. Finally, we found that the N1 component was sensitive to dynamic, but not static, PLWs, suggesting that this component reflects the processing of both form and motion information. The sensitivity of P1 to static PLWs has implications for dynamic form models of biological motion processing that posit temporal integration of configural cues present in individual frames of PLW animations.