Metabolism of a phenylcoumaran substructure lignin model compound in ligninolytic cultures of Phanerochaete chrysosporium

The degradation of the phenylcoumaran substructure model compound methyl dehydrodiconiferyl alcohol by the white-rot wood decay fungus Phanerochaete chrysosporium was investigated using culture conditions optimized for lignin oxidation. Initial attack was in the cinnamyl alcohol side chain, which was oxidized to a glycerol structure. This was subsequently converted by loss of the two terminal carbon atoms, C and C, to yield a C-aldehyde structure, which was further oxidized to the C-acid compound. The next detected intermediate, a phenylcoumarone, was produced by double bond formation between C and C, and oxidation of the C-alcohol to an aldehyde group. Further oxidation of C to an acid yielded the next intermediate. The final identified degradation product was veratric acid. No products from the 5-substituted aromatic ring, and no phenolic products, were found. The initial glycerol-containing intermediate was a mixture of the threo and erythro forms, and no optical activity could be found, suggesting that its formation might have involved nonstereospecific C-C epoxidation followed by non-enzymatic hydrolysis of the epoxide.Abbreviations TLC thin layer chromatography - LDA lithium diisopropyl amide - DDQ 2,3-dichloro-5,6-dicyanobenzoquinone - MS mass spectrometry - UV ultraviolet spectroscopy     

Labdane diterpene derivatives from Holwaya mucida

Clumps of white crystals present in 40-day-old malt agar cultures of Holwaya mucida were isolated as long white needles by crystallization from ethanol following short extraction with chloroform. The levorotary compound ([] ₂₈₉ ²¹ =-193.8°) was recognized as a -lactone (C₁₇H₂₀O₅) by infrared and mass spectrometry. It was identified as 7-methoxy-3a, 10b-dimethyl-1, 2, 3, 3a, 5a, 7, 10b, 10c-octahydro-4H, 9H-furo[2, 3, 4 : 4, 5]naphtho[2, 1-c]pyran-4, 9-dione, a labdane-derived compound known as antibiotic LL-Z1271. Preparative thin-layer chromatography of the mother liquor afforded 2 minor metabolites. One was identified as LL-Z1271, the demethylated analogue of LL-Z1271. The other one named LL-Z1271, was recognized as a compound related to and : its structure could not be fully elucidated. H. mucida (anamorph: Crinula calciiformis) has no taxonomic relationship with two other LL-Z1271 producing species viz. Acrostalagmus sp. (= Acremonium cf. atrogriseum) and Oidiodendron truncatum.     

Phenylacetic acid-induced somatic embryogenesis in cultured hypocotyl explants of geranium (Pelargonium x hortorum Bailey)

Summary The effect of a non-indole compound, phenylacetic acid (PAA), on the induction of somatic embryogenesis in tissue cultures of geranium (Pelargonium x hortorum Bailey cv. Scarlet Orbit Improved) was investigated. Hypocotyl explants derived from young, dark-grown seedlings were cultured on Murashige and Skoog (1962) medium (MS) supplemented with PAA or IAA (0.01–120 M) alone or in combination with BAP (8 M). Somatic embryogenesis was induced by both PAA and IAA at 0.01–20 M with 8 M BAP, however, the optima differed considerably for the two compounds. Maximal activity of IAA for somatic embryogenesis was found at 0.1–2.5 M, whereas PAA gave best results at 10 and 20 M under identical culture conditions. Higher concentrations (30–120 M) of IAA or PAA in the medium induced callusing in the explants, but the callus was neither embryogenic nor morphogenic.Abbreviations BAP N⁶-benzylaminopurine - IAA indole-3-acetic acid - MS Murashige and Skoog (1962) - PAA phenylacetic acid     

Selection of isoresponsive genotypes in toria (Brassica campestris L.) based on the pattern of response to environmental variations: a proposed method

Summary Thirty-one toria genotypes were compared with three well-established cultivars, Ludhiana Composite-2, K-1 and TCSU-2 (standard testers). The genotypes, which were almost identical to a standard tester in response to environmental variations and which also had other desirable characteristics, were considered to be acceptable for commercial cultivation. Using this criterion, TCSU-7, TH-5 and TH-4 were found to be acceptable for commercial cultivation. TH-4 and TCSU-7 were found superior to TH-5 if r² can be considered as a measure of the agronomical manipulations expected in environmental variations.     

Species and Tissue Distribution of Proteins Binding 16α,17α-Cycloalkanoprogesterone Derivatives

The binding of [³H]progesterone and [³H]16,17-cycloalkanoprogesterones to proteins from rat, rabbit, and human uteri and other organs was studied. We found that 16,17-cycloalkanoprogesterone derivatives display affinities for the uterine progesterone receptors comparable with that of the natural hormone and no substantial species differences in the affinity. Rabbit uterus was found to have no proteins distinct from the progesterone receptor that specifically bind [³H]16,17-cycloalkanoprogesterones. At the same time, in the human uterus, we found another protein that binds some of these progesterone derivatives; it turned out to be similar to the protein from rat uterus. A similar protein with the same selectivity and affinity for steroids was also found in rat and human kidneys. Blood serum, liver, lung, and a number of other tissues were found to contain a protein of the third type that binds the same 16,17-cycloalkanoprogesterones and exhibits submicromolar K _d values for these steroids and a very low affinity for progesterone. We speculated that the introduction of a bulky substituent adjacently to the 17-side chain of progesterone could result in a change in the general biodynamics of the derivative including its transport, uptake, and accumulation in tissues, which may determine the selectivity of its effect.     

Thidiazuron substitution for chilling requirement in three apple cultivars

Thidiazuron [(TDZ)N-phenyl-N-1,2,3-thidiazol-5-ylurea] at 750 M was applied to buds of apple trees to determine if it could substitute for the chilling requirement to induce bud break. Shoots of cv. Anna (low chill), Delicious cv. Redchief (medium chill), and Northern Spy (high chill) were untreated, treated with TDZ prior to chilling (before-chill), and treated with TDZ at various intervals after the accumulation of specific amounts of chilling (after-chill). Shoots were stored in a cold room at 4°C. TDZ applied prior to chilling reduced the chill unit (CU) requirement (1 CU = 1 h at 4°C) for the promotion of bud break on 1-year-old shoots of Anna and Northern Spy and 1- and 2-year-old wood of Delicious. TDZ applied after-chill promoted bud break only for Anna and buds on 2-year-old wood of Delicious. While accumulating CUs, untreated buds or buds treated with TDZ on 1-year Delicious and Northern Spy did not respond to the cold treatment even after 1848 h of CU accumulation. For all three cultivars, TDZ treatment was more effective in promoting bud break when applied before the initiation of chilling.The use of a company or product name does not constitute an endorsement by USDA or the University of Maryland nor imply approval to the exclusion of other suitable products.     

The effect of antibiotics on the inhibition of callus induction and plant regeneration from cotyledons of sugarbeet (Beta vulgaris L.)

Callus induction and plantlet regeneration from cotyledonary expiants of sugarbeet was observed utilizing two media formulations, MS and a modified MS termed RVIM both supplemented with 1.0 g/ml BAP as the sole growth regulator. Callus induction was genotype dependent The USDA line 8787 produced the highest response for callus induction followed by Betaseed 4587 and the USDA line C600. This order was conserved on both media formulations. Shoot induction was consistently higher averaging 32% from the RVIM formulation over the 3 genotypes compared to 25% from MS. The antibiotics geneticin, gentamycin, hygromycin, kanamycin and phleomycin were screened with the modified RV system utilizing Betaseed 4587. Callus growth was inhibited by levels of 50 g/ml geneticin, 150 g/ml gentamycin, 10 g/ml hygromycin, 150 g/ml kanamycin and 20 g/ml phleomycin. The results indicate that the concentrations of antibiotics used to inhibit callus induction will be sufficient for use as selectable markers in transformation experiments with Beta vulgaris.Abbreviations B₅ basal medium (Gamborg et al, 1968) - BAP N⁶-Benzylaminopurine - IBA Indole-3-butanoic acid - MS basal medium (Murashige and Skoog 1968) - RVIM modified MS basal medium (Freytag et al, 1988) - MES (2[N-Morpholino] ethanesulfonic acid     

Furoquinoline alkaloid accumulation in Fagara zanthoxyloides cell cultures is highly dependent on the presence of exogenous benzylaminopurine

Culturing a non-habituated cell line of Fagara zanthoxyloides Lam. (Rutaceae) in either auxin-free medium or cytokinin-free medium led to opposite effects on furoquinoline accumulation. It appeared that production of skimmianine and -fagarine in the cells was strongly correlated with the presence of exogenous BAP: the levels of both alkaloids were 9 times lower when cells were cultured without cytokinin than in the control culture. NAA removal induced a slight stimulation of skimmianine and -fagarine accumulations, 1.2 and 1.9 times respectively. Culturing the cells in a PGR-free medium generated skimmianine and -fagarine levels that were 3.5 and 2.1 times lower, respectively, confirming the opposite effects of BAP and NAA on furoquinoline accumulation. Growth was only slightly inhibited when cells were cultured for one passage in the PGR-modified media.Abbreviations BAP 6-benzylaminopurine - MS Murashige-Skoog - NAA -naphtaleneacetic acid - PGR plant growth regulator     

Entwicklungsgeschichtliche Untersuchungen an zentrischen Diatomeen IV

Zusammenfassung 1. Die Entwicklung vonStephanopyxis turris sowie die zu ihrer Untersuchung geeigneten Methoden werden beschrieben und diskutiert.2. Der vollständige Lebenszyklus einer zentrischen Diatomee nach Beobachtungen im Leben und mit den Grundzügen der zugehörigen Karyologie in Mitose, Meiosis, Befruchtung und Auxosporenbildung sowie Entstehung und Keimung der Dauersporen wird erstmalig dargestellt (Abb. 18).3. Neuartige Beobachtungen betreffen Kollaps, Blitztod und Lichtresistenz, die Dritte Linie, die Darstellung von Kern und Spindel in Mitose und Meiosis sowie die mit Kernkonkurrenz abschließenden acytokinetischen Karyokinesen in Oogon und Auxospore im Leben, die Keimung der Dauersporen, den lichtmikroskopischen Nachweis der Kieselschuppen in der Auxosporenmembran.4. Die Entwicklungsvorgänge werden vergleichend diskutiert und dabei die Termini depauperierende Teilung und heterovalvate Zytokinese in Vorschlag gebracht.5. Weitere Überlegungen gelten dem cyclischen Turgeszenzwechsel der Diatomeenzelle.6. Die Methode der Vegetativen Zellvergrößerung erlaubt es,Stephanopyxis-Klone beliebiger Breite aber unveränderten Genotypus für das Experiment bereitzustellen.

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Ontogenetic investigations on centric diatoms IVThe planktonic diatomStephanopyxis turris — its treatment and life history

This paper presents a detailed account of the life cycle, development and cellular mechanics of the centric diatomS. turris. Special attention is paid to culture methods, nutritional requirements and the mechanism of vegetative cell enlargement. Instructions are outlined for experimental manipulations of developmental features. Various aspects of development are treated in details, e. g. cellular structures, cell division and morphogenesis, development and germination of resting spores, differentiation of gametangia (spermatogonangia, spermatogonia and oogonia), meiosis in the gametocytes, fertilization and auxospore differentiation (including the formation of the rejuvenated first cell and the accompanying metagamic mitoses).S. turris has one-egged oogonia. Its spermatogonangia develop their spermatogonia according to theBiddulphia granulata-type and their spermiums according to theMelosira-type (Fig. 18). Two new termini, i. e. heterovalvate cytokinesis and depauperizing mitosis are introduced (p. 232, p. 238). Among the more important results are observations on karyokinesis in vivo, meiosis and karyogamy, and on the peculiar process of destruction of supernumerary nuclei following each karyokinesis in the oocyte, and later in the young auxospore. Relations between osmotic cell rhythms, karyokinetic cycle and morphogenesis are discussed at the end of the paper.

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Herrn Professor Dr.Adolf Bückmann zum 65. Geburtstag in Verehrung gewidmet.

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Diese Studie enthält Teile der Dissertation vonG. Drebes.     

Regio- and stereo-selective synthesis of vinyl glucose ester catalyzed by an alkaline protease of Bacillus subtilis

The transesterification of -d-glucose with divinylsuccinate, divinyladipate and divinylsebacate in pyridine at 55 °C for 3 days was catalyzed by an alkaline protease from Bacillus subtilis to give corresponding 6-O-vinyl glucose esters at 30%, 53% and 35% yield, respectively. The stereo-selectivity of the alkaline protease toward the -anomer was affected by the acyl donor chain length. 6-O-Vinylsuccinyl-d-glucose was mixture of - and -anomers (/=44/56), the other two products were the pure -d-glucose derivatives.     

High D-glucose does not affect binding of α-tocopherol to human erythrocytes

The role of -tocopherol uptake system in human erythrocyte in the uptake of plasma -tocopherol has been suggested. However no information is available on -tocopherol uptake activity of human erythrocytes in the presence of high levels of D-glucose which is known to lead to pathological alterations in different cells including human erythrocytes. Therefore, in order to examine the effect of D-glucose on the binding of -tocopherol to human erythrocytes, the binding characteristics of -tocopherol to these cells were established first. Binding of [3H]-tocopherol to human erythrocytes was both saturable and specific. Scatchard analysis of -tocopherol binding to these cells showed the presence of two independent classes of binding sites with widely different affinities. The high affinity binding sites had a dissociation constant (Kd1) of 90 nM with a binding capacity (n1) of 900 sites per cell, whereas the low affinity binding sites had a dissociation constant (Kd2) of 5.2 M and a binding capacity (n2) of 105,400 sites per cell. Trypsin treatment abolished all the -tocopherol binding activity. Competition for the binding of -tocopherol to human erythrocytes was effective with other homologues of -tocopherol (-tocopherol, -tocopherol and -tocopherol) and their potency was almost equal to -tocopherol itself. The order of preference was -tocopherol > -tocopherol -tocopherol -tocopherol. Incubation of human erythrocytes with various concentrations of D-glucose did not affect -tocopherol uptake activity. Our data demonstrate the presence of an -tocopherol uptake system in human erythrocytes and that the -tocopherol uptake activity is not modulated by the presence of D-glucose.     

Genetics of resistance to Puccinia graminis tritici in ‘Chris’ and ‘W3746’ wheats

Summary Chris wheat possessed genes Sr5, Sr7a, Sr8a, Sr9g and Sr12. W3746, derived from the cross Chris/Baart, possessed Sr7a and Sr12. The response conferred by Sr7a was influenced by the genetic background. Although Sr7a or Sr12 alone conferred no observable resistance upon adult plants, the adult resistances of Chris and W3746 to predominant pathotypes appeared to be associated with the interaction of Sr7a and Sr12, or genes at closely linked loci.     

Rapid clonal propagation of Dioscorea zingiberensis

A protocol was developed for rapid in vitro propagation of Dioscorea zingiberensis Wright using stems as explants. MS medium with the macroelements at half strength and supplemented with 20.0 g l^–1 sucrose and 8.0 g l^–1 agar was used as basal medium. Lateral buds on nodal cuttings grew into shoots within 20 days after culture on basal medium supplemented with 4.4 M 6-benzylaminopurine (BAP) and 1.1 M -naphthalene acetic acid (NAA). The shoots were cut into segments and cultured on medium with 8.9 M BA and 5.4 M NAA for 30 days for callus formation. The callus was cut into pieces and cultured on medium containing 22.2 M BAP and 1.1 M NAA, on which 87.5% of the callus pieces regenerated multiple shoots within 50 days. The shoots were rooted on medium containing 4.9 M indole-3-butyric acid (IBA) for 20 days. Adventitious buds and shoots could be repeatedly formed after the calli were cut into pieces and cultured on the medium containing 8.9 M BAP plus 1.1 M NAA. More than 85% of the regenerated plantlets survived and grew vigorously 1 month after they were transplanted in vermiculite and each plant formed 2–4 microtubers 3 months of transplanting.     

Synthetic substrate analogues for UDP-GlcNAc: Manα1-6R β(1-2)-N-acetylglucosaminyltransferase II. Substrate specificity and inhibitors for the enzyme

UDP-GlcNAc: Man1-6R (1-2)-N-acetylglucosaminyltransferase II (GlcNAc-T II; EC 2.4.1.143) is a key enzyme in the synthesis of complexN-glycans. We have tested a series of synthetic analogues of the substrate Man1-6(GlcNAc1-2Man1-3)Man-O-octyl as substrates and inhibitors for rat liver GlcNAc-T II. The enzyme attachesN-acetylglucosamine in 1-2 linkage to the 2-OH of the Man1-6 residue. The 2-deoxy analogue is a competitive inhibitor (K _i=0.13mm). The 2-O-methyl compound does not bind to the enzyme presumably due to steric hindrance. The 3-, 4- and 6-OH groups are not essential for binding or catalysis since the 3-, 4- and 6-deoxy and -O-methyl derivatives are all good substrates. Increasing the size of the substituent at the 3-position to pentyl and substituted pentyl groups causes competitive inhibition (K _i=1.0–2.5mm). We have taken advantage of this effect to synthesize two potentially irreversible GlcNAc-T II inhibitors containing a photolabile 3-O-(4,4-azo)pentyl group and a 3-O-(5-iodoacetamido)pentyl group respectively. The data indicate that none of the hydroxyls of the Man1-6 residue are essential for binding although the 2- and 3-OH face the catalytic site of the enzyme. The 4-OH group of the Man-O-octyl residue is not essential for binding or catalysis since the 4-deoxy derivative is a good substrate; the 4-O-methyl derivative does not bind. This contrasts with GlcNAc-T I which cannot bind to the 4-deoxy-Man- substrate analogue. The data are compatible with our previous observations that a bisectingN-acetylglucosamine at the 4-OH position prevents both GlcNAc-T I and GlcNAc-T II catalysis. However, in the case of GlcNAc-T II, the bisectingN-acetylglucosamine prevents binding due to steric hindrance rather than to removal of an essential OH group. The 3-OH of the Man1-3 is an essential group for GlcNAc-T II since the 3-deoxy derivative does not bind to the enzyme. The trisaccharide GlcNAc1-2Man1-3Man-O-octyl is a good inhibitor (K _i=0.9mm). The above data together with previous studies indicate that binding of the GlcNAc1-2Man1-3Man- arm of the branched substrate to the enzyme is essential for catalysis. Abbreviations: GlcNAc-T I, UDP-GlcNAc:Man1-3R (1-2)-N-acetylglucosaminyltransferase I (EC 2.4.1.101); GlcNAc-T II, UDP-GlcNAc:Man1-6R (1-2)-N-acetylglucosaminyltransferase II (EC 2.4.1.143); MES, 2-(N-morpholino)ethane sulfonic acid monohydrate.     

Genetic analysis of two wheat cultivars, ‘Sonalika’ and ‘WL 711’ for reaction to leaf rust (Puccinia recondita)

Summary Genetic analysis for leaf rust reaction of two widely adapted cultivars, Sonalika and WL 711, has been done using 21 near isogenic Lr lines and rust culture IL004 — avirulent on the two cultivars and all the Lr lines used. The segregation pattern in the F₂ generation indicated the presence of a recessive gene in Sonalika and of a dominant gene in WL 711. These genes in cultivars Sonalika and WL 711 have been identified as Lr 11 and Lr 13, respectively. Gene Lr 13 is no longer effective in WL 711 but it continues to give field resistance in the backgrounds of Chris, Prelude and Thatcher. There has been no significant change in the virulence spectrum of the leaf rust pathogen in India with the release of WL 711. High susceptibility of WL 711 seems to be due to the evolution of more aggressive forms of the pathogen to this cultivar. The gene Lr 11, which behaves as a recessive in Sonalika, was effective against leaf rust when this cultivar was released. The high susceptibility of Sonalika is probably due to an increase in the frequency of race 77 virulent on Lr 11. Lr 11 has shown a dominance reversal in the background of Sonalika. Present results suggest that interaction of resistance genes with the background genotype must be studied for their effective use in breeding programme.     

Carbohydrates of influenza virus. Structure of the oligosaccharides linked to asparagines 406 and 478 in the hemagglutinin of fowl plague virus,strain dutch

Fowl plague virus, strain Dutch, was metabolically labeled withd-[2-³H]mannose, or withd-[6-³H]glucosamine, and the small subunit (HA₂; 0.8 mg in total) of the viral hemagglutinin was isolated by preparative sodium dodecylsulfate-polyacrylamide gel electrophoresis. After proteolytic digestion, the radioactive oligosaccharides were sequentially liberated from the glycopeptides by treatment with different endo--N-acetylglucosaminidases and with peptide:N-glycosidase or, finally, by hydrazinolysis. In this manner, four groups of glycans could be obtained by consecutive gel filtrations and were subfractionated by HPLC. The structures of the individual oligosaccharides were analyzed by micromethylation, by acetolysis or by digestion with exoglycosidases. The major species amongst the high mannose glycans at Ans-406 of the viral glycopolypeptide were found to be Man1-2Man1-3(Man1-2Man1-6)Man1-6(Man1-2Man1-2Man1-3)Man1-4GlcNac1-4GlcNAc and Man1-3(Man1-2Man1-6)Man1-6(Man1-2Man1-2Man1-3)Man1-4GlcNAc1-4GlcNAc, while the complex glycans at Asn-478 are predominantly GlcNAc1-2Man1-3(GlcNAc1-2Man1-6)Man1-4GlcNAc1-4GlcNAc (lacking, in part, one of the outerN-acetylglucosamine residues) and GlcNAc1-2Man1-3(Gal1-4GlcNAc1-2Man1-6)Man1-4GlcNAc1-4GlcNAc.Abbreviation BSA bovine serum albumin - endo D (F,H) endo--N-acetyl-d-glucosaminidase D (F,H) - HA hemagglutinin (HA₁, large subunit of HA - HA₂ small subunit - FPV fowl plague virus - PNGase F peptide:N-glycosidase F - SDS sodium dodecylsulfate     

Improved rate of callus induction from rice anther culture following microscopic staging of microspores in iron alum-haematoxylin

Summary High frequencies of callusing were obtained in indica rice from the microspores which were staged in acetic acid iron alum-haematoxylin stain prior to culture on G5 medium. Two local varieties, Khonorullo and Namyi, and two advance pre-release cultures, PK 1-1-3 and PK 12-22, were used in this investigation. All the cultures exhibited a wide adaptation to varying medium; however, the frequency of callusing was highest (45.5%) in PK 1-1-3 followed by PK 12-22 (32.4%) and Khonorullo (31.6%). Cold shock (10 °C) for 11 days enhanced the frequency of callusing by 200% in Khonorullo.     

Effects of light and acetate on the liberation of zoospores by a mutant strain ofChlamydomonas reinhardtii

In light-dark-synchronized cultures of the unicellular green algaChlamydomonas reinhardtii, release of zoospores from the wall of the mother cell normally takes place during the second half of the dark period. The recently isolated mutant ls, however, needs light for the liberation of zoospores when grown photoautotrophically under a 12 h light-12 h dark regime. The light-induced release of zoospores was found to be prevented by addition of the photosystem-II inhibitor 3-(3,4-dichlorophenyl)-1,1-dimethylurea. Furthermore, light dependence of this process was shown to be abolished when the mutant ls was grown either photoautotrophically under a 14 h light-10 h dark regime or in the presence of acetate. Our findings indicate that the light-dependency of zoospore liberation observed in cultures of this particular mutant during photoautotrophic growth under a 12 h light-12 h dark regime might be attributed to an altered energy metabolism. The light-induced release of zoospores was found to be prevented by addition of cycloheximide or chloramphenicol, antibiotics which inhibit protein biosynthesis by cytoplasmic and organellar ribosomes, respectively. Actinomycin D, an inhibitor of RNA synthesis, however, did not affect the light-induced liberation of zoospores.Sporangia accumulate in stationary cultures of the mutant ls. Release of zoospores was observed when these sporangia were collected by centrifugation and incubated in the light after resuspension in fresh culture medium. Since liberation of zoospores was not observed after dilution of the stationary cultures with fresh culture medium, we suppose that components which interfere with the action of the sporangial autolysin are accumulated in the culture medium of the mutant ls.Abbreviation DCMU 3-(3,4-dichlorophenyl)-1,1-dimethylurea     

Hexahydroindanone derivatives of steroids formed by Rhodococcus equi

Summary A mutant strain of Rhodococcus equi accumulates three metabolites from the androst-4-ene-3,17-dione or from its degradation intermediate, 3a-H-4(3'-propionic acid)-7a-methylhexahydro-1,5-indanedione (MEPHIP). These three metabolites are: 3a-H-4a(3'-propionic acid)-5-hydroxy-7a-methylhexahydro-1-indanone--lactone (HIL); 3a-H-4(3'-trans acrylic acid)-5-hydroxy-7a-methylhexahydro-1-indanone (^2'-5-hydroxy-MEPHIP); and 3a-H-4(3'-hydroxy-3'-propionic acid)-5-hydroxy-7a-methylhexahydro-1-indanone (3'-hydroxy-HIL). The behaviour of this mutant allows us to propose a pathway for degradation of the intermediates, methylperhydroindanone propionates. However, during this degradation, the side-chain propionate was eliminated by a-oxidation mechanism. Offprint requests to: A. Miclo     

Some observations on cyclodextrin-mediated boosting of secreted amylolytic enzymes byLactobacillus amylovorus

The amounts of a 160-kDa amylase and a 140-kDa -amylase (A. Burgess-Cassler and S. H. Imam, Curr. Microbiol. 23:207–213, 1991) secreted into culture medium by the starchutilizingLactobacillus amylovorus were enhanced by the use of cyclodextrin (CD) as the carbon source. The levels of total extracellular -amylase obtained with glucose as the carbon source could be boosted severalfold by use of CD. The best enhancer was -CD, and the rank order of best to least effective was -CD>-CD=-CD>glucose.Another amylase, a 65-kDa -amylase, which degraded para-nitrophenyl-(1,4)-d-glucopyranoside, was also detected in this study. The most effective enhancer in this case was -CD, and the rank order was -CD>-CD>-CD glucose. Despite its ability to degradep-nitrophenylated glucose, this enzyme did not convert maltose to glucose. It showed a cleared zone on starch zymograms and did degrade short maltodextrins to maltose. Neither this new -amylase nor the 140-kDa -amylase exhibited any detectable ring-decyclizing (cyclodextrinase) activity against -or -CD.Other extracellular amylases (not characterized here) appeared to be similarly enhanced by CDs. Although the precise mechanism by which this effect is accomplished remains undefined, CDs can be useful inducing agents, boosting the expression and/or secretion of otherwise low-level enzymes, either as additives to growth media or as sole carbon source.