Production of a thermostable alkali-tolerant xylanase from Bacillus circulans AB 16 grown on wheat straw

Bacillus circulans AB 16 was able to produce 50 IU/ml of xylanase, with negligible cellulase activity when grown on untreated wheat straw. The pH optimum of the crude enzyme was 6–7 with a temperature optimum of 80 C. The enzyme showed high pH and thermal stability retaining 100% activity at 60 C, pH 8 and 9 after 2.5 h of incubation. The residual activity at 70 C after 2.5 h was 62% and 45% at pH 8 and 9, respectively. At 75 C only 22.2% activity remained at pH 8 after 1 h incubation. Since Kraft pulp is alkaline this enzyme could be used for prebleaching of pulp at temperatures up to 70 C without pH adjustment.     

β-Thalassemia major resulting from a compound heterozygosity for the β-globin gene mutation: further evidence for multiple origin and migration of the thalassemia gene

Summary We describe in a Japanese family -thalassemia resulting from a compound heterozygosity for a -globin gene mutation. One mutation is a C-to-T transition at IVS-2 nucleotide position 654 on the background of Mediterranean haplotype IX. Another mutation is a G-to-A transition at IVS-2 nucleotide position 1, associated with a novel haplotype XL The occurrence of these mutations on various chromosomal backgrounds provides strong evidence for an interplay of gene migration, interallelic gene conversion, and multiple origins of the same mutation.     

Hainan Black-crested Gibbon Is Headed For Extinction

Although Hainan black-crested gibbons have been on the list of the most endangered primate species in the world for many years, their environment is still deteriorating, especially on Hainan Island. Our findings indicate that the species is unlikely to survive the next decades unless efficient conservation policies and strategies are put in place immediately. Census data show that populations of the species used to occur across the whole island, but in 2003 only 13 individuals could be found, confined to a small region, the Bawangling Natural Reserve (19 02¹–19 08¹N and 109 02¹–10913¹ E), in the western part of the island, covering only 14–16 km². In other words, ca. 99% of the habitat has vanished in the past 300 years. Such dramatic change has pushed the species to the edge of extinction; only 2 groups and 2 solitary adult males, remained in 2003. Two adult females, 2 juveniles and one infant comprise Group A, in Donger, the core area of the western part of the reserve; and 1 adult male, 2 adult females, 1 juvenile and 1 infant formed another group (B), confined to another core area (Nanchahe) in the northern part of the reserve. The dramatic decline in the gibbon population has occurred due to vegetation reduction, ecological deterioration and extensive human impact. The forest cover was reduced from 95.5% 2000 years ago to just 4% in 1999; and the human population in 2003 was 330% larger than in 1950.     

Effects of applied auxin,gibberellin and cytokinin on the activity of peroxidases in the peduncles of rose flowers

The activity of peroxidases in the proximal part of the flower peduncle of rose cv. Nubia was promoted by exogenous application of auxin but not by gibberellin or cytokinin. In cv. Mercedes the activity was promoted also by gibberellin and cytokinin. In the distal parts of the peduncles of both cultivars, peroxidase activity was not affected by any of the applied growth regulators. In young flowers of cv. Nubia the protein content of the penduncles was affected only by cytokinin, and in aged flowers only by auxin, while in Mercedes peduncles the content of protein was not affected by any of the applied growth regulators. The specific activity of peroxidases was promoted by auxin in peduncles of Nubia and by both auxin and cytokinin in peduncles of Mercedes flowers.     

LHRH-like system in the brain of Xenopus laevis daud

Summary Rabbit antiserum to synthetic LHRH was used with the immunofluorescence technique to identify the LHRH-secreting neurons and their axonal pathways in the brain of Xenopus laevis. Three groups of immunoreactive neurons were identified: the first, in the telencephalon, is a paired group of cells scattered near the two telencephalic ventricles; the second group lies near the preoptic recess; the third group occurs in the ventral wall of the infundibulum. Two principal neuronal pathways were observed: Fibres originating from the dorsally located telencephalic neurons converge on the cephalic median plane where they form a single bundle behind the telencephalic furrow. This bundle descends towards the anterior border of the preoptic recess where it divides into two nerve bundles which pass on either side of the preoptic recess, run above the optic chiasma then cross the infundibular floor and finally terminate in the median eminence. The second pathway is more direct. The more ventrally located telencephalic LHRH cells give rise to this second pathway. Their axons converge with the other LHRH fibres near the lateral border of the preoptic recess. Most of the LHRH nerve fibres terminate in the median eminence although some terminate near the paired pars tuberalis. No reaction was observed after the use of antiserum absorbed with synthetic antigen.Equipe de Recherche associée C.N.R.S. n 492. This work was financed by the D.G.R.S.T., Contract n 7470046     

An Analysis of the Amino Acid Clustering Pattern in (α/β)8 Barrel Proteins

The (/)₈ barrel proteins, in spite of having a common fold, do not show any sequence similarity. In order to understand the factors which are responsible for maintaining the common fold, the three-dimensional structures of 36 (/)₈ barrel proteins are analyzed for the presence of identical amino acid clusters or physicochemically similar clusters. The results reveal 14 identical amino acid clusters and a large number of physicochemically similar clusters. Further analysis of the similar clusters points to the conservation of secondary structures, the presence of pairs of residues occupying topologically equivalent secondary structures, and the presence of certain key residues which may play a vital role in directing and stabilizing the (/)₈ barrel fold.     

Enhanced acetyl esterase production by Fusarium oxysporum

Production of acetyl esterase (EC 3.1.1.6) by Fusarium oxysporum strain F3 was enhanced by optimization of growth conditions. Under optimal conditions, activities as high as 0.89U/ml of culture medium were obtained. The culture filtrate was equally active on p-nitrophenyl acetate and acetylxylan. The enzyme produced 71% deacetylation of acetylxylan in 2h at 40C. Activity was optimized at pH6.5 and at 55^C. The respective K_m values for p-nitrophenyl acetate and acetylxylan were 0.25mM and 1.05% (w/v) and the V_m values were 0.65 and 0.43mol acetate/min/mg protein.     

Desmosomes: Their occurrence between adjacent primary oocytes in polyovular follicles in the rabbit

Summary In polyovular, primordial follicles in the rabbit, desmosomes are found between apposing oocyte surfaces. Morphologically these desmosomes correspond closely to those described in epithelia of vertebrates. The desmosomes alternate with other junctions which are probably gap junctions.This work was supported in part by the G.R.S.T. Grant n 75.7.1313     

Molecular screening and fetal diagnosis of β-thalassemia in the Italian population

Summary This paper reports our experience of molecular screening and fetal diagnosis of -thalassemia in 457 at risk couples of Italian descent. Molecular screening was carried out by dot blot analysis on amplified DNA with oligonucleotide probes complementary to the eight most common mutations in Italians [39 (CT); 6 (-A); ⁺-87 (CG); ⁺ IVSI nt 110 (GA); IVSI nt 1 (GA); ⁺ IVSI nt 6 (TC); IVSII nt 1 (GA); ⁺ IVSII nt 745 (CG)]. By using this approach, we have been able to define the mutation in 92.8% of cases. The rest (all but four) were defined by direct sequencing and this led to the detection of nine rare mutations [76 (-C); ⁺ IVSI nt 5 (GA); ⁺ IVSI nt 5 (GC); ⁺ IVSI -1 (cod 30) (GC); ⁺-87 (CT), -290 bp del.; ⁺-101 (CT)], and to the characterization of a novel mutation consisting of the deletion of the G at the invariant AG of the IVSII splice acceptor site of the -globin gene ( IVSII nt 850-1 bp). In the remaining four cases, the -globin gene showed entirely normal sequences and the -globin gene cluster was intact, as indicated by Southern blot analysis. Fetal diagnosis was carried out by dot blot analysis with the oligonucleotide probes defined in the parents. The procedure is simple and reliable, and the results can be obtained within 1 week of sampling. No misdiagnosis has so far occurred. The results indicate that fetal diagnosis of -thalassemia by DNA analysis may be obtained in practically all cases (even in a population showing marked heterogeneity of -thalassemia) by the combination of dot blot analysis for detecting common mutations, and direct sequencing for defining those that are uncommon.     

Effect of aging on the morphology and function of the thyroid gland of the cream hamster

Summary The effect of aging on the morphology and function of the thyroid gland of the cream hamster was studied by light and electron microscopy coupled with autoradiography or histochemistry.Morphologically, aging induces an accumulation of lysosomal dense bodies and a loss of the phagocytosis of colloid droplets after stimulation with TSH. Iodine uptake and organification occur normally and thyroglobulin synthesis, estimated by autoradiography with ³H-leucine, is not different from that observed in young animals. The basal T₄ and T₃ plasma levels are lower in the old animals. A low iodine diet administered for several months prevents the age related accumulation of lysosomal dense bodies. Hormone secretion seems to proceed by two different mechanisms; phagocytosis of colloid droplets, the classical mechanism that decreases with age, and an additional mechanism, probably micropinocytosis, that is maintained during the whole lifespan.Presented at the First French Congress of Endocrinology, Montpellier, September 1980Work was performed under contracts n 3.4523.79 and n 3.4512.80 of the Fonds de la Recherche Scientifique Médicale, thanks to a grant of the Ministère Belge de la Politique Scientifique (Action concertée) and with the help of the Fondation Interuniversitaire pour la Recherche du Processus du Vieillissement, Belgium     

Analysis of DNA–Protein Contacts in a Complex between Methyltransferase SsoII and a Promoter Region of the SsoII Restriction–Modification Genes

Heterocyclic bases and phosphate groups involved in the DNA–methyltransferase SsoII (M·SsoII) interaction were identified in the regulatory DNA region localized within the promoter region of the SsoII restriction–modification genes by footprinting with the use of formic acid, hydrazine, dimethyl sulfate, and N-ethyl-N-nitrosourea as modifying agents. It has been established that the enzyme interacts with three guanines, one adenine, two thymines, and three phosphate groups of each strand of the DNA duplex. These heterocyclic bases and phosphate groups are disposed symmetrically within the 15-mer inverted repeat of the regulatory DNA region. It has been demonstrated by footprinting with dimethyl sulfate that the C7 atoms of guanines interacting with the enzyme are exposed to the DNA major groove. Two theoretical models were built describing the contacts in a complex between M·SsoII and the regulatory DNA region.     

Rapid detection of single nucleotide deletions: application to the β 6 (-A) mutation of the β-globin gene and to cystic fibrosis

The formation of heteroduplexes from the amplified products of homologous alleles has been shown to be useful in the identification of heterozygotes carrying deletion or insertion mutations. Here, we describe an improved procedure that allows the detection of single base pair (bp) deletions on nondenaturing polyacrylamide gels. Carriers for a common Mediterranean -thalassemic mutation, 6 (-A), could be easily detected by use of this method, as could carriers of a 1-bp deletion in the cystic fibrosis gene.     

Deutung und Herkunft des Namens der Lachm?we(Larus ridibundus L.)

Zusammenfassung Der deutsche und ebenso der Linnésche Name der Lachmöwe,Larus ridibundus, stammt von der zuerst mit ihr vereinigten amerikanischen Laughing Gull,Larus atricilla, und ist nach deren Stimme gebildet. Der Name wurde sodann auf die europäische Art übertragen und findet sich nun als Übersetzung in verschiedenen europäischen Sprachen.

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Summary The German name Lachmöwe and the scientific name Larus ridibundus as well of the Black-headed Gull seems to be deriven from the american Laughing Gull(Larus atricilla), which got at first its name fromBrisson after its voice, and was at first united with the Black-headed Gull(Larus ridibundus). This name then is transferred to the european species and is translated in various european languages.

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Herrn Prof. Dr. Ernst Schüz zum 70. Geburtstag gewidmet     

The electrical response ofAvena coleoptile cortex to auxins

Solute mobilities of 28 compounds in isolated cuticular membranes (CM) from Capsicum annuum L. fruit, Citrus aurantium L. and Pyrus communis L. leaves were studied using unilateral desorption from the outer surface. First-order rate constants of desorption (k^*), which are directly proportional to the diffusion coefficient in the waxy outer limiting skins of cuticles were measured. When log k^* was plotted vs. molar volumes of test compounds linear graphs were obtained. The y-intercepts of these graphs (k^*) represent the mobility of a hypothetical molecule having zero molar volume and the slopes of the graphs () represent the size selectivity of the barrier and are related to the free volume available for diffusion. Thus, solute mobilities in cuticles are composed of two independent terms which are subtractive. If k^* and are known, k^* can be estimated for any solute from its molar volume (V_x) using the equation log k^*=log k^* –V_x. These parameters were used to analyse the effects of plant species, extraction of cuticular waxes and molecular structure of solutes on solute mobilities in plant cuticles. For aliphatic solutes, k^* was a factor of 10 smaller than for cyclic compounds, while was 0.011 and 0.012, respectively. The k^*-values for CM of the three species were very similar, but was higher for bitter-orange CM (0.012) than for those of pepper fruits and pear leaves (0.009). This has the consequence that differences in solute mobilities (k^*) among cuticles from different plan species increase with increasing molar volumes of solutes. Our data and our analysis provide evidence that constituents of cuticular waxes are mobile, at least in the solid amorphous wax fraction, but mobility decreases rapidly with increasing molar volume. For instance, if amounts to 0.01, mobilities of wax monomers decrease by a factor of 10 for every increase in molar volume of 100 cm³ · mol^–1. Thus, hexadecanoic acid is quite mobile in the amorphous wax fraction of Citrus (k^*=1.5×10^–6·s^–1), but for dotriacontane having twice the molar volume, k^* was only 2.5×10^–9·s^–1, which is almost three orders of magnitude smaller. Wax esters have even higher molar volumes and their mobilities will be even smaller (about 4×10^–12·s^–1 for a C₄₈-ester). Since low chain mobilities are a prerequisite for low mobilities and permeabilities, the selective advantage of high-molecular-weight wax monomers in plant cuticular waxes becomes obvious. Extracting cuticular waxes from pear leaf CM increased solute mobilities by a factor of 182, but it had no effect on size selectivity. We interpret this result as evidence to the effect that cuticular waxes reduce mobility by increasing tortuosity of the diffusion path, rather than by decreasing the mean free path of diffusional jumps and jump frequencies of diffusants.Abbreviations CM cuticular membrane(s) - 2,4-D 2,4-dichloro-phenoxyacetic acid - LAB lactic acid buffer - MX polymer matrix membranes - UDOS unilateral desorption from the outer surface     

Gibberellins play a role in the interaction between imidazole fungicides and cytokinins in Araceae

Imidazole fungicides such as imazalil, prochloraz, and triflurnizole and the triazole growth retardant paclobutrazol promote the shoot-inducing effect of exogenous cytokinins in Araceae, such as Spathiphyllum floribundum Schott and Anthurium andreanum Schott. The mechanism of their action could partially be based on the inhibition of gibberellic acid (GA) biosynthesis, because administration of GA₃ inhibits the phenomenon completely in S. floribundum. Not only is the suppression of GA biosynthesis involved, but also the metabolism of endogenous cytokinins is significantly altered. Although the balance between isopentenyladenine, zeatin, dihydrozeatin, and their derivatives was shifted to distinguished directions by administration of BA and/or imazalil and/or GA₃, no correlation between these changes in metabolic pathways and the number of shoots could be found. The metabolism of BA was not significantly altered by adding imazalil to the micropropagation medium of S. floribundum.Abbreviations 2,4-D 2,4-dichlorophenoxyacetic acid - [9R-5P]DHZ 9--d-ribofuranosyl-dihydrozeatin-monophosphate - [9R-5P]iP 6-isopentenyl-9--d-ribofuranosyladenine-monophosphate - [9R-5P]Z 9--d-ribofuranosyl-zeatin-monophosphate - [9G]BA 6-benzyl-9--d-glucopyranosyladenine - [9G]DHZ 9--d-glucopyranosyl-dihydrozeatin - [9G]iP 6-isopentenyl-9--d-glucopyranosyladenine - [9G]Z 9--d-glucopyranosyl-zeatin - [9R]BA 6-benzyl-9--d-ribofuranosyladenine - [9R]DHZ 9--d-ribofuranosyl-dihydrozeatin - [9R]iP 6-isopentenyl-9--d-ribofuranosyladenine - [9R]Z 9--d-ribofuranosyl-zeatin - BA 6-benzyladenine - DHZ dihydrozeatin - ES⁺ LC-MS/MS HPLC coupled Electrospray Tandem Mass Spectrometry - f.m. fresh mass - mT 6-(3-hydroxybenzyl)adenine - IMA imazalil - iP isopentenyladenine - NAA 1-naphthalene acetic acid - NFT Nutrient Film Technique - (OG)[9R]DHZ O--glucopyranosyl-9--d-ribofuranosyl-dihydrozeatin - (OG)[9R]Z O--d-glucopyranosyl-9--d-ribofuranosyl-zeatin - (OG)DHZ O--d-glucopyranosyl-dihydrozeatin - (OG)Z O--d-glucopyranosyl-zeatin - PAR Photosynthetic Active Radiation - PBZ paclobutrazol - PRO prochloraz - TDZ thidiazuron - TRI triflurnizole - Z zeatin     

Analyse des échanges de chromatides dans les cellules somatiques humaines

A new technique (BUdR treatment followed by acridine orange staining) allowing a differentiation of sister chromatids is described. A statistical analysis of 91 human karyotypes gives an estimate of the frequency of exchanges. The mean of sister chromatid exchanges is 27,3 and the minimum number is 11 per cell. — The frequency of these exchanges is proportional to the relative length of each chromosome, and the accumulation of several exchanges in some segments evokes the possibility of a negative interference. — The analysis of endomitoses treated with BUdR during at least two generations is not in disagreement with the model of semi-conservative replication of chromosomal DNA, but the modifications of the chromatids may result from a completely different process. — The frequency of endomitoses is increased by the treatment. These endomitoses allow a very precise analysis of the evolution of the sister chromatid exchanges, during two successive cellular generations.

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Travail de l'E.R.A. N 47 du C.N.R.S. et C.E.A. Contrat N 293.     

Effect of pimozide on the cytology of the eel pituitary

Summary Pimozide, a specifie blocker of dopaminergic receptors, was injected for 4 or 9 days in freshwater (FW) eels or eels acclimated to sea water (SW) for 10 or 30 days. The daily dose was 100 or 200 g/100g. Melanophore index values increase in FW and in 1 month-SW injected eels. All the treated fish react by a total or subtotal degranulation of the lead-hematoxylin positive cells in the pars intermedia. These cells were previously identified as -MSH-secreting cells. The MSH cell nuclear area is significantly increased, nucleoli are larger and the endoplasmic reticulum more developed. The intensity of the response is similar in FW and SW eels, but it does not increase with the higher dose. The rapid release of pituitary -MSH is also visualized by immunofluorescence and immunoenzymologic techniques. No effect on the second cell type of the pars intermedia (PAS-positive cell) is detected. The amount of neurosecretory material is often reduced in the neurohypophysis. These results suggest that the hypothalamic inhibitory control of MSH release and synthesis is mediated through dopaminergic fibers in the eel, but other factors cannot be ignored in this regulation.The author is grateful to Dr. P.A.J. Janssen for donating the pimozide used in this experiment and to Jacqueline Olivereau, from the C.N.R.S., for her excellent technical assistance. This work was supported by the Centre National de la Recherche Scientifique and a grant from the Délégation Générale à la Recherche Scientifique et Technique (n A 650 1588)     

The combined effect of high hydrostatic pressure,heat and bacteriocins on inactivation of foodborne pathogens in milk and orange juice

The objective of this study was to combine pressure (345 MPa) with heat (50 C), and bacteriocins (5000 AU/ml sample) for a short time (5 min) for the inactivation of relatively pressure-resistant strains of four foodborne pathogens: Staphylococcus aureus, Listeria monocytogenes, Escherichia coli O157:H7 and Salmonella in pasteurized milk and orange juice. Without bacteriocin addition, 5.5 log-cycle reduction was obtained for S. aureus 485 in milk whereas more than 8 log-cycle reduction was achieved for all the other strains studied. After storage of samples for 24 h at 4 C, S. aureus 765 also gave positive results on selective media, where no growth was observed for all the other micro-organisms assayed. Incubation of the same pressurized samples at 37 C for 48 h showed growth of L. monocytogenes strains in addition to S. aureus strains, where still no growth was observed for E. coli O157:H7 and Salmonella strains in their respective selective media. For orange juice samples, more than 8 log-cycle reduction was achieved for all the bacterial species studied. No growth was seen for these species on their respective selective media agar plates after storage at 4 C for 24 h and at 37 C for 48 h. When a bacteriocin-based biopreservative (BP₁) was combined with pressurization, more than 8 log-cycle reduction in cell population of the resistant strains of S. aureus and L. monocytogenes were achieved in milk after pressurization. Milk samples were stored at 25 C up to 30 days to test the effect of treatment and samples showed no growth whereas all the controls were positive.     

Meiotic recombination in an Irish family with beta-thalassaemia

Using the technique of allele-specific priming of the polymerase chain reaction (PCR), the C-T substitution in codon 39 was identified as the cause of -thalassaemia in an Irish family. Analysis of the restriction fragment length polymorphisms (RFLPs) in the -globin gene cluster established linkage of the -thalassaemia mutation to a particular -haplotype but indicated that a recombinational event had occurred in the paternal chromosome in the younger of two affected children. Non-paternity was excluded by DNA fingerprinting analysis with hypervariable minisatellite probes. This is the fourth case of recombination in the -globin gene cluster to be reported. The event has occurred 5 of the polymorphic RsaI site at position-550 bp upstream of the -globin gene mRNA Cap site, within the 9.1-kb region that has been shown to be a hot spot for recombination in the -globin gene cluster.