Functional characterization of the pollen-specific <Emphasis Type="Italic">SBgLR</Emphasis> promoter from potato (<Emphasis Type="Italic">Solanum tuberosum</Emphasis> L.)

SBgLR (Solanum tuberosum genomic lysine-rich) gene was isolated from a potato genomic library using SB401 (S. berthaultii 401) cDNA as probe. RT-PCR analysis of SBgLR gene expression profile and microscopic analysis of green fluorescent protein (GFP) expression in tobacco plants transformed with SBgLR promoter-GFP reporters indicate that SBgLR is a pollen-specific gene. A series of 5′deletions of SBgLR promoter were fused to the β-glucuronidase (GUS) gene and stably introduced into tobacco plants. Histochemical and quantitative assays of GUS expression in transgenic plants allowed us to localize an enhancer of SBgLR promoter to the region −345 to −269 relative to the translation start site. This 76 bp (−345 to −269) fragment enhanced GUS expression in leaves, stems and roots when fused to −90/+6 CaMV 35S minimal promoter. Deletion analysis showed that a cis-element, which can repress gene expression in root hairs, was located in the region −345 to −311. Further study indicated that the −269 to −9 region was sufficient to confer pollen-specific expression of GFP when fused to CaMV 35S enhancer. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. Authors Zhihong Lang and Peng Zhou contributed equally to this work.     

Tyrosol and tryptophol produced by <Emphasis Type="Italic">Ceratocystis adiposa</Emphasis>

Extracellular tyrosol and tryptophol were produced and isolated from the phytopathogen fungus Ceratocystis adiposa cultivated in a rich broth. These compounds have not been previously reported in this Ceratocystis species, as its identification was established through spectroscopic methods (¹H NMR, ¹³C NMR and MS). Productivity of tyrosol and tryptophol was 65.3 and 44 μg l⁻¹ day⁻¹, respectively, which were values higher than those reported to date. Tyrosol is a compound of pharmaceutical interest showing antioxidating activity, a property used in the treatment of atherosclerosis. Tryptophol is reported to have antibiotic and phytotoxic activity.     

Overproduction of soluble recombinant transglutaminase from <Emphasis Type="Italic">Streptomyces netropsis</Emphasis> in <Emphasis Type="Italic">Escherichia coli</Emphasis>

A novel microbial transglutaminase (TGase) from the cultural filtrate of Streptomyces netropsis BCRC 12429 (Sn) was purified. The specific activity of the purified TGase was 18.2 U/mg protein with an estimated molecular mass of 38 kDa by sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis. The TGase gene of S. netropsis was cloned and an open reading frame of 1,242 bp encoding a protein of 413 amino acids was identified. The Sn TGase was synthesized as a precursor protein with a preproregion of 82 amino acid residues. The deduced amino acid sequence of the mature S. netropsis TGase shares 78.9–89.6% identities with TGases from Streptomyces spp. A high level of soluble Sn TGase with its N-terminal propeptide fused with thioredoxin was expressed in E. coli. A simple and efficient process was applied to convert the purified recombinant protein into an active enzyme and showed activity equivalent to the authentic mature TGase. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

<Emphasis Type="Italic">TfPLC1</Emphasis>, a gene encoding phosphoinositide-specific phospholipase C,is predominantly expressed in reproductive organs in <Emphasis Type="Italic">Torenia fournieri</Emphasis>

Phosphoinositide-specific phospholipase C (PI-PLC) is an important enzyme, which is a key player involved in eukaryotic signal transduction pathways. In plants, it plays a key role in growth and development as well as environmental stress. However, little is known about its roles in signal transduction during sexual reproduction process. In this study, we cloned and characterized a gene of full-length PI-PLC from ovules of Torenia fournieri, designated as TfPLC1. It was 2,171 bp in length, including an open reading frame encoding a polypeptide of 583 amino acids with molecular mass of 66.02 kDa. The amino acid sequence deduced from the cDNA sequence shows 40–76% similarity to other plant PI-PLCs and contains the characteristic X, Y and C2 domains. Northern blot analysis demonstrated it was predominantly expressed in ovules and flowers. Furthermore, TfPLC1 promoter::GUS transgenic analysis indicated it specifically expressed in ovule, stigma and mature pollen grain. Immunohistochemical staining showed that, in mature stigma, TfPLC1 protein was principally localized in the cells of stigmatic receptive surface. Together, our data suggest that TfPLC1 may play an important role in plant sexual reproduction. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

<Emphasis Type="Italic">Drosophila</Emphasis><Emphasis Type="Italic">P</Emphasis> transposons of the urochordata <Emphasis Type="Italic">Ciona intestinalis</Emphasis>

P transposons belong to the eukaryotic DNA transposons, which are transposed by a cut and paste mechanism using a P-element-coded transposase. They have been detected in Drosophila, and reside as single copies and stable homologous sequences in many vertebrate species. We present the P elements Pcin1, Pcin2 and Pcin3 from Ciona intestinalis, a species of the most primitive chordates, and compare them with those from Ciona savignyi. They showed typical DNA transposon structures, namely terminal inverted repeats and target site duplications. The coding region of Pcin1 consisted of 13 small exons that could be translated into a P-transposon-homologous protein. C. intestinalis and C. savignyi displayed nearly the same phenotype. However, their P elements were highly divergent and the assumed P transposase from C. intestinalis was more closely related to the transposase from Drosophila melanogaster than to the transposase of C. savignyi. The present study showed that P elements with typical features of transposable DNA elements may be found already at the base of the chordate lineage. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

<Emphasis Type="Italic">In vitro</Emphasis> propagation of <Emphasis Type="Italic">Decalepis arayalpathra</Emphasis>, a critically endangered ethnomedicinal plant

Summary This study reports a protocol for successful micropropagation of Decalepis arayalpathra (Joseph and Chandras) Venter. (Janakia arayalpathra Joseph and Chandrasekhran; Periplocaceae), a critically endangered and endemic ethnomedicinal plant in the southern forests of the Western Ghats which is overexploited for its tuberous medicinal roots by the local Kani tribes. Natural regeneration is rare and conventional propagation is difficult. Conservation of the species through micropropagation was attempted. The nodal explants of greenhouse-raised plants, were more desirable than cotyledonary nodal explants of aseptic seedlings. The basal nodes (73%) of 12–16-wk-old greenhouse-grown plants cultured in Murashige and Skoog (MS) medium containing 12.96 μM 6-benzyladenine (BA), 2.48 μM 2-isopentenyladenine (2-ip) and 2.68 μM α-naphthaleneacetic acid (NAA) formed 16–17 cm long unbranched robust solitary shoots in 8 wk. Cotyledonary nodal explants cultured in the same medium showed multiple shoot formation and axillary branching. But the shoots were thin, fragile and not suitable for mass propagation. Single nodes of a solitary shoot subcultured on MS medium containing 2.22 μM BA and 0.24 μM 2-ip together produced 9.8±0.3 nodes from 18.0±0.6 cm long shoots within 5–6 wk. The basal nodes of the shoots so formed were repeatedly subcultured to increase the stock of propagules while the 2.5–3.0 cm terminal cuttings were used for rooting. The best root induction (68%) and survival (86%) was achieved on half-strength MS medium supplemented with 1.07 μM NAA. Field-established plants showed uniform growth and phenotypic similarity to parental stock.     

Study of tauopathies by comparing <Emphasis Type="Italic">Drosophila</Emphasis> and human <Emphasis Type="Italic">tau</Emphasis> in <Emphasis Type="Italic">Drosophila</Emphasis>

The microtubule-binding protein tau has been investigated for its contribution to various neurodegenerative disorders. However, the findings from transgenic studies, using the same tau transgene, vary widely among different laboratories. Here, we have investigated the potential mechanisms underlying tauopathies by comparing Drosophila (d-tau) and human (h-tau) tau in a Drosophila model. Overexpression of a single copy of either tau isoform in the retina results in a similar rough eye phenotype. However, co-expression of Par-1 with d-tau leads to lethality, whereas co-expression of Par-1 with h-tau has little effect on the rough eye phenotype. We have found analogous results by comparing larval proteomes. Through genetic screening and proteomic analysis, we have identified some important potential modifiers and tau-associated proteins. These results suggest that the two tau genes differ significantly. This comparison between species-specific isoforms may help to clarify whether the homologous tau genes are conserved. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. This study was supported by the National Science Foundation of China (30270341; 30630028), the Multidisciplinary Program (Brain and Mind) of the Chinese Academy of Sciences, the Major State Basic Research Program (“973 program”; G2000077800; G2006CB806600; 2006CB911003), the Precedent Project of Important Intersectional Disciplines in the Knowledge Innovation Engineering of the Chinese Academy of Sciences (KJCX1-09-03).     

<Emphasis Type="Italic">In vitro</Emphasis> flowering of <Emphasis Type="Italic">Perilla frutescens</Emphasis>

This study investigated the factors affecting in vitro flowering of Perilla frutescens. The shoots regenerated from cotyledonary and hypocotyl explants cultured on Murashige and Skoog (MS) medium supplemented with benzyladenine (BA) and indole-3-acetic acid, each at 0.5 mg l⁻¹, were excised and transferred to MS medium containing 30 g l⁻¹ of sucrose, 8.25 g l⁻¹ of ammonium nitrate, and 1.0 mg l⁻¹ of BA. After 40 d of culture, 86.2% of shoots flowered and most of which self-fertilized in vitro and produced mature fruits with viable seeds. These seeds were germinated and plants were grown to maturity and flowered in soil under greenhouse conditions. The in vitro flowering system reported in this study may facilitate rapid breeding of P. frutescens and offers a model system for studying the physiological mechanism of flowering.     

Actinomycetemcomitin: a new bacteriocin produced by <Emphasis Type="Italic">Aggregatibacter</Emphasis> (<Emphasis Type="Italic">Actinobacillus</Emphasis>) <Emphasis Type="Italic">actinomycetemcomitans</Emphasis>

Aggregatibacter (Actinobacillus) actinomycetemcomitans P_7–20 strain isolated from a periodontally diseased patient has produced a bacteriocin (named as actinomycetemcomitin) that is active against Peptostreptococcus anaerobius ATCC 27337. Actinomycetemcomitin was produced during exponential and stationary growth phases, and its amount decreased until it disappeared during the decline growth phase. It was purified by ammonium sulphate precipitation (30–60% saturation), and further by FPLC (mono-Q ionic exchange and Phenyl Superose hydrophobic interaction) and HPLC (C-18 reversed-phase). This bacteriocin loses its activity after incubation at a pH below 7.0 or above 8.0, following heating for 30 min at 45°C, and after treatment with proteolytic enzymes such as trypsin, α-chymotrypsin, and papain. Actinomycetemcomitin has a molecular mass of 20.3 KDa and it represents a new bacteriocin from A. actinomycetemcomitans.     

Cloning and expression of <Emphasis Type="Italic">mel</Emphasis> gene from <Emphasis Type="Italic">Bacillus thuringiensis</Emphasis> in <Emphasis Type="Italic">Escherichia coli</Emphasis>

Previous work from our laboratory has shown that most of Bacillus thuringiensis strains possess the ability to produce melanin in the presence of l-tyrosine at elevated temperatures (42 °C). Furthermore, it was shown that the melanin produced by B. thuringiensis was synthesized by the action of tyrosinase, which catalyzed the conversion of l-tyrosine, via l-DOPA, to melanin. In this study, the tyrosinase-encoding gene (mel) from B. thuringiensis 4D11 was cloned using PCR techniques and expressed in Escherichia coli DH5 . A DNA fragment with 1179 bp which contained the intact mel gene in the recombinant plasmid pGEM1179 imparted the ability to synthesize melanin to the E. coli recipient strain. The nucleotide sequence of this DNA fragment revealed an open reading frame of 744 bp, encoding a protein of 248 amino acids. The novel mel gene from B.thuringiensis expressed in E. coli DH5 conferred UV protection on the recipient strain.     

Purification and Properties of an <Emphasis Type="Italic">N</Emphasis>-acetylglucosaminidase from <Emphasis Type="Italic">Streptomyces cerradoensis</Emphasis>

An N-acetylglucosaminidase produced by Streptomyces cerradoensis was partially purified giving, by SDS-PAGE analysis, two main protein bands with Mr of 58.9 and 56.4 kDa. The K_m and V_max values for the enzyme using p-nitrophenyl-β-N-acetylglucosaminide as substrate were of 0.13 mM and 1.95 U mg⁻¹ protein, respectively. The enzyme was optimally activity at pH 5.5 and at 50 °C when assayed over 10 min. Enzyme activity was strongly inhibited by Cu²⁺ and Hg²⁺ at 10 mM, and was specific to substrates containing acetamide groups such as p-nitrophenyl-β-N-acetylglucosaminide and p-nitrophenyl-β-D-N,N′-diacetylchitobiose.     

Double deletion of <Emphasis Type="Italic">dtsR1</Emphasis> and <Emphasis Type="Italic">pyc</Emphasis> induce efficient <Emphasis Type="SmallCaps">l</Emphasis>-glutamate overproduction in <Emphasis Type="Italic">Corynebacterium glutamicum</Emphasis>

Corynebacterium glutamicum strains are used for the fermentative production of l-glutamate. Five C. glutamicum deletion mutants were isolated by two rounds of selection for homologous recombination and identified by Southern blot analysis. The growth, glucose consumption and glutamate production of the mutants were analyzed and compared with the wild-type ATCC 13032 strain. Double disruption of dtsR1 (encoding a subunit of acetyl-CoA carboxylase complex) and pyc (encoding pyruvate carboxylase) caused efficient overproduction of l-glutamate in C. glutamicum; production was much higher than that of the wild-type strain and ΔdtsR1 strain under glutamate-inducing conditions. In the absence of any inducing conditions, the amount of glutamate produced by the double-deletion strain ΔdtsR1Δpyc was more than that of the mutant ΔdtsR1. The activity of phosphoenolpyruvate carboxylase (PEPC) was found to be higher in the ΔdtsR1Δpyc strain than in the ΔdtsR1 strain and the wild-type strain. Therefore, PEPC appears to be an important anaplerotic enzyme for glutamate synthesis in ΔdtsR1 derivatives. Moreover, this conclusion was confirmed by overexpression of ppc and pyc in the two double-deletion strains (ΔdtsR1Δppc and ΔdtsR1Δpyc), respectively. Based on the data generated in this investigation, we suggest a new method that will improve glutamate production strains and provide a better understanding of the interaction(s) between the anaplerotic pathway and fatty acid synthesis.     

Exopolysaccharide production of <Emphasis Type="Italic">Lactobacillus salivarius</Emphasis> BCRC 14759 and <Emphasis Type="Italic">Bifidobacterium bifidum</Emphasis> BCRC 14615

In the present study, the production of exopolysaccharides (EPS) by 13 strains of Lactobacillus and 6 strains of Bifidobacterium in a chemical defined medium (CDM) supplemented with 30 g lactose/l was first compared. The highest EPS production of the Lactobacillus strains was found in L. salivarius BCRC 14759 while among the Bifidobacterium strains examined, B. bifidum BCRC 14615 showed the highest EPS production. Analyzes of the effect of lactose concentration and cultivation temperature on EPS production revealed that L. salivarius produced the highest amount of EPS (45.3 mg/l) in CDM supplemented with 5 g lactose/l at 40°C while B. bifidum produced the highest EPS (17.0 mg/l) in CDM supplemented with 40 g lactose/l at 35°C. α-Phosphoglucomutase, UDP-glucose pyrophosphorylase and UDP-galactose-4-epimerase exhibited a markedly notable activity compared with other enzymes examined in the cell extract of both test organisms. This indicates their possible involvement in the biosynthesis of EPS.     

<Emphasis Type="Italic">In vitro</Emphasis> bud regeneration of <Emphasis Type="Italic">Carthamus tinctorius</Emphasis> and wild <Emphasis Type="Italic">Carthamus</Emphasis> species from leaf explants and axillary buds

The organogenic competence of leaf explants of eleven Carthamus species including C. tinctorius on Murashige and Skoog (MS) medium supplemented with different concentrations of thidiazuron (TDZ) + α-naphthaleneacetic acid (NAA) and 6-benzyladenine (BA) + NAA was investigated. Highly prolific adventitious shoot regeneration was observed in C. tinctorius and C. arborescens on both growth regulator combinations and the shoot regeneration frequency was higher on medium supplemented with TDZ + NAA. Nodal culture of nine Carthamus species on media supplemented with BA and kinetin (KIN) individually revealed the superiority of media supplemented with BA over that of KIN in facilitating a higher shoot proliferation index. Proliferating shoots from axillary buds and leaf explants were transferred to medium supplemented with 1.0 mg dm⁻³ KIN or 0.5 mg dm⁻³ BA for shoot elongation. Elongated shoots were rooted on half-strength MS medium supplemented with 1.0 mg dm⁻³ each of indole-butyric acid (IBA) and phloroglucinol. The plantlets thus obtained were hardened and transferred to soil.     

Random segment deletion based on IS<Emphasis Type="Italic">31831</Emphasis> and Cre/<Emphasis Type="Italic">loxP</Emphasis> excision system in <Emphasis Type="Italic">Corynebacterium glutamicum</Emphasis>

A simple and random genome deletion method combining insertion sequence (IS) element IS31831 and the Cre/loxP excision system generated 42 Corynebacterium glutamicum mutants (0.2–186 kb). A total of 393.6 kb (11.9% of C. glutamicum R genome) coding for 331 genes was confirmed to be nonessential under standard laboratory conditions. The deletion strains, generated using only two vectors, varied not only in their lengths but also the location of the deletion along the C. glutamicum R genome. By comparing and analyzing the generated deletion strains, identification of nonessential genes, the roles of genes of hitherto unknown function, and gene–gene interactions can be easily and efficiently determined. Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users.     

Transgenic resistance to <Emphasis Type="Italic">Cymbidium mosaic virus</Emphasis> in <Emphasis Type="Italic">Dendrobium</Emphasis> expressing the viral capsid protein gene

A Taiwan isolate of Cymbidium mosaic virus (CymMV-CS) was isolated from infected Cymbidium sinesis Willd. The cDNA of the capsid protein (CP) gene was synthesized and sequenced. Alignment of this CP gene with other reported CPs revealed homologies of 92–98% at the nucleotide level and 98–99% at the amino acid level. To generate virus-resistant varieties, the CymMV-CS CP gene was transformed into Dendrobium protocorms through particle bombardment. Transformants were selected on medium supplemented with 20 mg/L hygromycin and the presence of the transgene was confirmed by polymerase chain reaction, Southern, Northern and Western blot analyses. Transgenic Dendrobium harboring the CymMV CP gene expressed a very low level of virus accumulation four months post-inoculation with CymMV, as detected by ELISA. The transgenic plants exhibited much milder symptoms than the non-transgenic plants upon challenge with CymMV virionsSequence data reported from this article have been deposited at the GenBank Data Libraries under Accession No. AY429021.     

Efficient expression in <Emphasis Type="Italic">E. coli</Emphasis> of an enantioselective nitrile hydratase from <Emphasis Type="Italic">Rhodococcus erythropolis</Emphasis>

The genes encoding an enantioselective nitrile hydratase (NHase) from Rhodococcus erythropolis AJ270 have been cloned and an active NHase has been produced in Escherichia coli. Maximal activity was found when the genes encoding the α- and β-subunits were transcribed as one unit and the gene encoding the P44k activator protein as a separate ORF on a single replicon. Addition of n-butyric acid and FeSO₄ could improve NHase activity. Coexpression of the GroEL-GroES chaperone proteins increased activity in the absence of P44k protein but had no effect in the presence of P44k. The recombinant enzyme was highly enantioselective in the synthesis of S-(+)-3-benzoyloxy- 4-cyanobutyramide from the prochiral substrate 3-benzoyloxyglutaronitrile.     

Characterization of <Emphasis Type="SmallCaps">d</Emphasis>-tagatose-3-epimerase from <Emphasis Type="Italic">Rhodobacter sphaeroides</Emphasis> that converts <Emphasis Type="SmallCaps">d</Emphasis>-fructose into <Emphasis Type="SmallCaps">d-</Emphasis>psicose

A non-characterized gene, previously proposed as the d-tagatose-3-epimerase gene from Rhodobacter sphaeroides, was cloned and expressed in Escherichia coli. Its molecular mass was estimated to be 64 kDa with two identical subunits. The enzyme specificity was highest with d-fructose and decreased for other substrates in the order: d-tagatose, d-psicose, d-ribulose, d-xylulose and d-sorbose. Its activity was maximal at pH 9 and 40°C while being enhanced by Mn²⁺. At pH 9 and 40°C, 118 g d-psicose l⁻¹ was produced from 700 g d-fructose l⁻¹ after 3 h. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.