Ten different Polycomb group genes are required for spatial control of the abdA and AbdB homeotic products.

Mutations in genes of the Polycomb (Pc) group cause abnormal segmental development due to ectopic expression of the homeotic products of the Antennapedia and bithorax complexes. Here the requirements for Pc group genes in controlling the abdA and AbdB products of the bithorax complex are described. Embryos containing mutations in the genes Polycomb (Pc), extra sex combs (esc), Enhancer of zeste [E(z)], polyhomeotic (ph), Sex comb on midleg (Scm), Polycomb-like (Pcl), Sex comb extra (Sce), Additional sex combs (Asx), Posterior sex combs (Psc) and pleiohomeotic (pho) were examined. In every case, both abdA and AbdB are expressed outside of their normal domains along the anterior-posterior (A-P) axis, consistent with these Pc group products acting in a single pathway or molecular complex. The earliest detectable ectopic expression is highest in the parasegments immediately adjacent to the normal expression boundary. Surprisingly, in the most severe Pc group mutants, the earliest ectopic AbdB is distributed in a pair-rule pattern. At all stages, ectopic abdA in the epidermis is highest along the anterior edges of the parasegments, in a pattern that mimics the normal abdA cell-specific pattern. These examples of highly patterned mis-expression show that Pc group mutations do not cause indiscriminate activation of homeotic products. We suggest that the ectopic expression patterns result from factors that normally activate abdA and AbdB only in certain parasegments, but that in Pc group mutants these factors gain access to regulatory DNA in all parasegments.     

Isolation and physiological study of an amylolytic strain of Lactobacillus plantarum

Summary An amylolytic lactic acid bacterium identified as Lactobacillus plantarum was isolated from cassava roots (Manihot esculenta var. Ngansa) during reting. The amylolytic enzyme synthesized was an extracellular -amylase with an optimum pH of 5.0 and an optimum temperature of 55° C. Cultured on starch, the strain displayed a growth rate of 0.43 h^–1, a biomass yield of 0.19 g·g^–1 and a lactate yield of 0.81 g·g^–1. The growth kinetics were similar on starch and glucose. Sufficient enzyme was synthesized and starch hydrolysis was not a limiting factor for growth. Biosynthesis of the enzyme was observed when the glucose concentration was less than 6.7 g·l^–1 and reached up to 4 IU·ml^–1 at the end of the fermentation. Offprint requests to: M. Raimbault     

Nucleosomal organization of chromatin in sperm nuclei of the bivalve mollusc Aulacomya ater

The sperm nuclei of Aulacomya ater, family Mitylidae, contain three proteins (X, Aa5 and Aa6) which are specific to this cell type coexisting with a set of five somatic-type histones. Information about the chromatin structure resulting from this kind of association is scarce. Therefore, we have probed the structure of this sperm chromatin through digestion with micrococcal nuclease in combination with salt fractionation. The data obtained have allowed us to propose a nucleosomal arrangement for this chromatin. However, two types of nucleosomes would be present in agreement with their protein components.     

Localization of neuropeptide Y-immunoreactive cells and fibres in the brain of the Japanese quail

Summary In the present study, we have demonstrated, by means of the biotin-avidin method, the widespread distribution of neuropeptide Y (NPY)-immunoreactive structures throughout the whole brain of the Japanese quail (Coturnix coturnix japonica). The prosencephalic region contained the highest concentration of both NPY-containing fibres and perikarya. Immunoreactive fibres were observed throughout, particularly within the paraolfactory lobe, the lateral septum, the nucleus taeniae, the preoptic area, the periventricular hypothalamic regions, the tuberal complex, and the ventrolateral thalamus. NPY-immunoreactive cells were represented by: a) small scattered perikarya in the telencephalic portion (i.e. archistriatal, neostriatal and hyperstriatal regions, hippocampus, piriform cortex); b) medium-sized cell bodies located around the nucleus rotundus, ventrolateral, and lateral anterior thalamic nuclei; c) small clustered cells within the periventricular and medial preoptic nuclei. The brainstem showed a less diffuse innervation, although a dense network of immunopositive fibres was observed within the optic tectum, the periaqueductal region, and the Edinger-Westphal, linearis caudalis and raphes nuclei. Two populations of large NPY-containing perikarya were detected: one located in the isthmic region, the other at the boundaries of the pons with the medulla. The wide distribution of NPY-immunoreactive structures within regions that have been demonstrated to play a role in the control of vegetative, endocrine and sensory activities suggests that, in birds, this neuropeptide is involved in the regulation of several aspects of cerebral functions.Abbreviations AA archistriatum anterius - AC nucleus accumbens - AM nucleus anterior medialis - APP avian pancreatic polypeptide - CNS centrai nervous system - CO chiasma opticum - CP commissura posterior - CPi cortex piriformis - DIC differential interferential contrast - DLAl nucleus dorsolateralis anterior thalami, pars lateralis - DLAm nucleus dorsolateralis anterior thalami, pars medialis - E ectostriatum - EW nucleus of Edinger-Westphal - FLM fasciculus longitudinalis medialis - GCt substantia grisea centralis - GLv nucleus geniculatus lateralis, pars ventralis - HA hyperstriatum accessorium - Hp hippocampus - HPLC high performance liquid chromatography - HV hyperstriatum ventrale - IF nucleus infundibularis - IO nucleus isthmo-opticus - IP nucleus interpeduncularis - IR immunoreactive - LA nucleus lateralis anterior thalami - LC nucleus linearis caudalis - LFS lamina frontalis superior - LH lamina hyperstriatica - LHRH luteinizing hormone-releasing hormone - LoC locus coeruleus - LPO lobus paraolfactorius - ME eminentia mediana - N neostriatum - NC neostriatum caudale - NPY neuropeptide Y - NIII nervus oculomotorius - NV nervus trigeminus - NVI nervus facialis - NVIIIc nervus octavus, pars cochlearis - nIV nucleus nervi oculomotorii - nIX nucleus nervi glossopharyngei - nBOR nucleus opticus basalis (ectomamilaris) - nCPa nucleus commissurae pallii - nST nucleus striae terminalis - OM tractus occipitomesencephalicus - OS nucleus olivaris superior - PA palaeostriatum augmentatum - PBS phosphate-buffered saline - POA nucleus praeopticus anterior - POM nucleus praeopticus medialis - POP nucleus praeopticus periventricularis - PP pancreatic polypeptide - PYY polypeptide YY - PVN nucleus paraventricularis magnocellularis - PVO organum paraventriculare - R nucleus raphes - ROT nucleus rotundus - RP nucleus reticularis pontis caudalis - Rpc nucleus reticularis parvocellularis - RPgc nucleus reticularis pontis caudalis, pars gigantocellularis - RPO nucleus reticularis pontis oralis - SCd nucleus subcoeruleus dorsalis - SCv nucleus subcoeruleus ventralis - SCNm nucleus suprachiasmaticus, pars medialis - SCNl nucleus suprachiasmaticus, pars lateralis - SL nucleus septalis lateralis - SM nucleus septalis medialis - Ta nucleus tangentialis - TeO tectum opticum - Tn nucleus taeniae - TPc nucleus tegmenti pedunculo-pontinus, pars compacta - TSM tractus septo-mesencephalicus - TV nueleus tegmenti ventralis - VeL nucleus vestibularis lateralis - VLT nucleus ventrolateralis thalami - VMN nucleus ventromedialis hypothalami A preliminary report of this study was presented at the 15th Conference of European Comparative Endocrinologists, Leuven, Belgium, September 1990     

Electrotransformation of Streptococcus pyogenes with plasmid and linear DNA

Electrotransformation was used to introduce both plasmid and linear DNA into Streptococcus pyogenes. The method was optimized using strain NZ131, for which transformation frequencies up to 10(7) per micrograms of plasmid DNA were obtained. A linear fragment of DNA, containing the streptokinase gene (ska) in which an internal fragment had been replaced with an erythromycin resistance gene (erm), was transformed into strain NZ131 with a frequency of 10(3) per micrograms DNA. The introduction of linear DNA into S. pyogenes by electrotransformation should be useful for future genetic analyses as well as targeted gene replacement.     

Cellular heterogeneity and insulin-like growth factor I immunoreactivity among epiphysial growth plate chondrocytes in the pig

The localization of insulin-like growth factor I (IGF-I, also called somatomedin C) production in porcine epiphysial growth plates of the distal humerus was studied by immunohistochemistry. Counterstaining with Alcian blue-van Gieson demonstrated two cell types (blue and red cells) in the germinal (reserve), proliferating and hypertrophic zones; only those chondrocytes of the proliferative and hypertrophic zones that stained red were also immunoreactive to the antibody to IGF-I. The results indicate that there exists a functional heterogeneity among the chondrocytes of both the proliferative and hypertrophic zones of growth cartilage and that IGF-I is locally produced in only the red cells of these zones. Because the red cells of the germinal zone were not immunoreactive, the results suggest that the red cells of the germinal zone and the red cells of the proliferative and hypertrophic zones are also functionally distinct.     

The glutamine residues reactive in transglutaminase-catalyzed cross-linking of involucrin

The protein involucrin, synthesized by human keratinocytes, contains 585 amino acids, largely in the form of 10 amino acid repeats, each containing glutamines in 3 conserved positions. Involucrin is a substrate for the keratinocyte transglutaminase and is labeled by the cosubstrate amine, glycine ethyl ester. Study of tryptic peptides of involucrin shows that a single glutamine (residue 496), located 89 residues from the C-terminal end, is preferentially labeled by the enzyme. Additional glutamine residues become reactive when the molecule is fragmented. The C-terminal end, isolated as a cyanogen bromide fragment of 275 residues, is labeled equally at 2 glutamine residues. The polypeptide containing residues 148 to 280 accepts practically no amine while in intact involucrin but as a free fragment is labeled at multiple glutamine residues. It is concluded that the C-terminal and N-terminal ends of the protein are directive influences in that they suppress the reactivity of a number of glutamine residues in the intact molecule, leaving one glutamine highly preferred by the transglutaminase.     

Ethinylestradiol administration selectively alters liver sinusoidal membrane lipid fluidity and protein composition

Administration of high-dose ethinylestradiol to rats decreases bile flow, Na,K-ATPase specific activity, and liver plasma membrane fluidity. By use of highly purified sinusoidal and bile canalicular membrane fractions, the effect of ethinylestradiol administration on the protein and lipid composition and fluidity of plasma membrane fractions was examined. In sinusoidal fractions, ethinylestradiol (EE) administration decreased Na,K-ATPase activity (32%) and increased activities of alkaline phosphatase (254%), Mg2+-ATPase (155%), and a 160-kDa polypeptide (10-fold). Steady-state and dynamic fluorescence polarization was used to study membrane lipid structure. Steady-state polarization of diphenylhexatriene (DPH) was significantly higher in canalicular compared to sinusoidal membrane fractions. Ethinylestradiol (5 mg/kg per day for 5 days) selectively increased sinusoidal polarization values. Similar changes were demonstrated with the probes 2- and 12-anthroyloxystearate. Time-resolved fluorescence polarization measurements indicated that EE administration for 5 days did not change DPH lifetime but increased the order component (r infinity) and decreased the rotation rate (R). However, 1 and 3 days after EE administration and with low doses (10-100 micrograms/kg per day for 5 days) the Na,K-ATPase, bile flow, and order component were altered, but the rotation rate was unchanged. Vesicles prepared from total sinusoidal membrane lipids of EE-treated rats, as well as phospholipid vesicles, demonstrated increased DPH polarization, as did intact plasma membrane fractions. Liver plasma membrane fractions showed no change in free cholesterol or cholesterol/phospholipid molar ratio, while esterified cholesterol content was increased with high-dose but not low-dose ethinylestradiol.(ABSTRACT TRUNCATED AT 250 WORDS)