Batch-feeding whole-cell catalytic synthesis of α-arbutin by amylosucrase from Xanthomonas campestris

Journal of Industrial Microbiology & Biotechnology - α-Arbutin is an effective skin-whitening cosmetic ingredient and can be synthesized through hydroquinone glycosylation. In this study,...     

Untersuchungen über die Spermiogenese beim Sandläufer,Cicindela campestris L.

Zusammenfassung Wie das Spermium von Lepisma besitzt dasjenige von Cicindela das Zentriol in parapikaler Stellung. Es besteht kein Kontakt mit dem Akrosom.Bereits auf frühem Spermatidenstadium wird die Kernsubstanz in zwei unterschiedliche Bestandteile getrennt, denen ganz bestimmte Bezirke der Kernmembran zugeordnet sind. Der größere Teil des Kernmaterials liegt in feinverteilter Form vor; die ihn umgebende Kernmembran enthält keine Poren. Er wandelt sich nach bekanntem Schema zum Kern des reifen Spermiums um. Der kleinere Teil besitzt granuläre Struktur und liegt in einer vorgewölbten Blase, in deren Bereich die Kernmembran mit Poren übersät ist. Im Laufe der Differenzierung wird diese Blase zusammen mit dem Zentriol von der Basis an die Spitze verlagert. Sie scheidet dabei offenbar kontinuierlich ihren Inhalt in das Zytoplasma aus. Sobald sie sich vollständig entleert hat, wird sie abgeschnürt und verfällt der Rückbildung. Das sezernierte Material sammelt sich zunächst größtenteils um das Zentriol. Abschließend jedoch verteilt es sich entlang der Geißel, wobei eine gebogene Lamelle nicht ohne Einfluß zu sein scheint.Die Bedeutung dieser eigenartigen Kernsekretion ist vorerst unklar. Es gibt aber liehtmikroskopische Befunde, die auf eine weitere Verbreitung mindestens unter Insekten hinweisen. Angesichts der vorgelegten Befunde scheint auch eine Revision der Ansicht, daß das perizentrioläre Material bei vielen anderen Arten aus dem Zentriol hervorgehe, geboten.Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.     

Xanthomonas campestris, a novel stress tolerant, phosphate-solubilizing bacterial strain from saline–alkali soils

A total of 198 bacterial strains were isolated from various niches of saline–alkali soils, out of which 85 strains were able to solubilize phosphate on plates at 30 °C. The strain RMLU-26, identified as Xanthomonas campestris, was the most efficient with its ability to solubilize P, subjected to N-methyl-N′-nitro-N-nitrosoguanidine (NTG) for development of mutants. The P solubilizing ability of X. campestris is reported for the first time. The wild type and mutant strains of X. campestris revealed a differential response to various stress factors (high pH, temperature, and salt concentration). The mutant strain revealed maximum P solubilization (67.1%) at 30 °C and pH 8.0 while the wild type strain showed maximum solubilization (41.9%) at 35 °C and pH 7.0. Percent P₂O₅ solubilization by both strains revealed a steep decline in tricalcium phosphate solubilization with an increase in NaCl concentration from 0.5 to 10% along with a concomitant drop in pH of the medium from 8.0 to 4.5 in wild type and 4.0 in mutant strain. However, a 1.5- to 2-fold increase in ‘P’ solubilization was observed in the mutant strain when compared to the wild type strain in the presence of NaCl. The overall improved tolerance of the strains to alkalinity and salinity could be due to accumulation and/or secretion of specific solute (xanthan).     

Combining ability and maternal effects in Brassica campestris L. var. ‘yellow sarson’

Summary A diallel analysis of combining ability, including maternal effects, genotype X environment interaction and the progress under selection, is reported in three selected crosses of Brassica campestris L. var. yellow sarson, involving 15 types, including 10 four-valved and 5 two-valved types from different parts of India. Twelve characters, including oil content, were studied in the f₁ generation.The investigation has revealed only marginal superiority of f₁'s over the parents for most of the characters related to yield. There was no relation between heterozygosity and stability of performance over environments for yield or its components or for oil content. Substantial maternal effects were observed which also interacted with environments. Creation of variation for primary and secondary branches would be essential for changing yield level in yellow sarson. The presence of limited additive variation available for selection for yield components should be augmented by biparental mating the early segregating generations to break linkages, and was demonstrated by the recombinants obtained when this method was adopted.The magnitude of genotype — environment interactions in this study, as compared with the total genetic components for yield, oil content, number of siliquae on main axis and presence of large reciprocal variances in relation to general and specific combining ability variances for practically all characters, and the large interaction of , narrowed down the expected effectiveness of selection.Biparental mating in the three best crosses yielded three new recombinants outyielding the best check T 10 by the margins of 14%, 39% and 15%, respectively, in the yield trial. These recombinants had more primary branches and secondary branches, larger main axes and more siliquae with an increased number of seeds per siliqua, than any of the F₁'s in this study.     

油菜Brassica campestris花期云南罗平本地传粉蜂的两种生境——山林生境和农田生境

正本期报道了外来西方蜜蜂Apis mellifera放蜂密度对云南罗平本地传粉蜂群落结构及物种多样性的影响(pp. 343-353)。照片由董坤于2016年2月23日摄于云南省罗平县板桥镇。Front cover:Photo shows two habitats,wooded mountain habitat and farmland habitat, of native pollinating bees in Luoping, Yunnan,     

The construction of a genetic linkage map of non-heading Chinese cabbage （Brassica campestris ssp. chinensis Makino）

Non-heading Chinese cabbage （Brassica carnpestris ssp. chinensis Makino） is one of the most important vegetables in eastern China. A genetic linkage map was constructed using 127 doubled haploid （DH） lines, and the DH population was derived from a commercial hybrid ＂Hanxiao＂ （lines SW-13 x L-118）. Out of the 614 polyrnorphic markers, 43.49% were not assigned to any of the linkage groups （LGs）. Chi-square tests showed that 42.67% markers were distorted from expected Mendelian segregation ratios, and the direction of distorted segregation was mainly toward the paternal parent L-118. After sequentially removing the markers that had an interval distance smaller than 1 cM from the upper marker, the overall quality of the linkage map was increased. Two hundred and sixty-eight molecular markers were mapped into 10 LGs, which were anchored to the corresponding chromosome of the B. rapa reference map based on com- mon simple sequence repeat （SSR） markers. The map covers 973.38 cM of the genome and the average interval distance between markers was 3.63 cM. The number of markers on each LG ranged from 18 （R08） to 64 （R07）, with an average interval distance within a single LG from 1.70 cM （R07） to 6.71 cM （R06）. Among these mapped markers, 169 were sequence-related amplified polymorphism （SRAP） molecular markers, 50 were SSR markers and 49 were random amplification polymorphic DNA （RAPD） markers. With further saturation to the LG9 the current map offers a genetic tool for loci analysis for important agronomic traits.     

Construction of stable lactose-utilizing Xanthomonas campestris by chromosomal integration of cloned lac genes using filamentous phage ϕLf DNA

Summary Previously, we constructed a lactose-utilizing strain of Xanthomonas campestris, Xc17 (pKMLT), by cloning lacZY genes with the RK2-derived vector pLAFR1. In this study, the narrow-host-range, -galactosidase expression plasmid pKM was fused with an integration vector pS19 to form pSF14. Following insertion into Xc17, pSF14 was integrated into the host chromosome. The integration function was provided by the 0.85-kb EcoRI-PstI fragment from the filamentous phage Lf. The integration caused no adverse effect to the cells and was stable for at least 66 generations without selection. The engineered strain, Xc17::pSF14, was able to grow as well and produce as much xanthan gum in lactose medium as the wild-type cells did in glucose medium, and the Xc17(pKMLT) in lactose medium. Therefore, Xc17::pSF14 is potentially useful for xanthan production by direct use of whey lactose as the fermentation substrate. This study has advanced one more step our efforts to contruct lactose-utilizing X. campestris and confirmed the feasibility of using pS19 as an integration vector.     

Growth and Major Nutrient Concentrations in Brassica campestris Supplied with Different NH4^＋/NO3 Ratios

In the present study, we investigated whether growth and main nutrient ion concentrations of cabbage （Brassica campestris L.） could be increased when plants were subjected to different NH4^＋/NO3- ratios. Cabbage seedlings were grown in a greenhouse in nutrient solutions with five NH4^＋/NO3- ratios （1：0; 0.75：0.25; 0.5：0.5; 0.25：0.75; and 0：1）. The results showed that cabbage growth was reduced by 87% when the proportion of NH4^＋-N in the nutrient solution was more than 75% compared with a ratio NH4^＋/NO3- of 0.5：0.5 35 d after transplanting, suggesting a possible toxicity due to the accumulation of a large amount of free ammonia in the leaves. When the NH4＋/NO3- ratio was 0.5：0.5, fresh seedling weight, root length, and H2PO4- （P）, K^＋, Ca^2＋, and Mg^2＋ concentrations were all higher than those in plants grown under other NH4^＋/NO3- ratios. The nitrate concentration in the leaves was the lowest in plants grown at 0.5： 0.5 NH4^＋/NO3-. The present results indicate that an appropriate NH4^＋/NO3- ratio improves the absorption of other nutrients and maintains a suitable proportion of N assimilation and storage that should benefit plant growth and the quality of cabbage as a vegetable.     

Torpor patterns in the pouched mouse (Saccostomus campestris ; Rodentia): a model animal for unpredictable environments

Patterns of spontaneous and induced daily torpor were measured in the Afrotropical pouched mouse (77–115?g), Saccostomus campestris, in response to photoperiod, temperature, and food deprivation, using temperature telemetry. Photoperiod had no influence on the incidence, depth, or duration of daily torpor in either males and females. Although the testis size index decreased in response to food deprivation and photoperiod by a maximum of 24%, full testis regression did not occur. Torpor bout duration was, on average, 5.3?h, independent of photoperiod and ambient temperature. Males did not enter torpor in response to food deprivation but did in response to low ambient temperature, though significantly less frequently than females. At normothermia, the body temperatures (daily minimum, mean, maximum) of males were significantly lower than those of females. Minimum body temperatures of both males and females during torpor did not fall below 20?°C at an ambient temperature of 15?°C. The patterns of torpor measured here differ from those observed in species from strongly seasonal environments. They suggest adaptation to an environment rendered unpredictable by the El Niño Southern Oscillations. As an aseasonal, opportunistic breeder capable of year-round adaptive hypothermia, the pouched mouse represents an excellent model animal for research on physiological and behavioral adaptations to unpredictable environments.     

黄单胞菌(Xanthomonas campestris)XA5-5β-葡萄糖苷酶基因的克隆与表达

以黄单胞菌(Xanthomonas campestris)XA5-5为供体菌,广泛寄主质粒pRK404为载体,在大肠杆菌中克隆了一个β-葡萄糖苷酶基因,重组质粒pLZS1外源片段为1.1kb,将pLZS1接合导入黄单胞菌XA5-5,得到了克隆子XA5-5(pLZS1).以水杨苷为底物,XA5-5(pLZS1)的酶活性大大高于E.Coli JM83(pLZS1).并且质粒在XA5-5中能相对稳定地存在.初步结果表明,所克隆的基因编码的产物对于水杨苷底物有较强的亲和力,并可以在一定程度上降低XA5-5中酶与pNPG底物的亲和力,使其酶活减小.     

Cloning and characterization of the hemA gene for synthesis of δ-aminolevulinic acid in Xanthomonas campestris pv. phaseoli

The gene from Xanthomonas campestris pv. phaseoli that is involved in the C5 pathway of -amino-levulinic acid (ALA) of Escherichia coli. Subcloning of deletion fragments from the initial 2.5-kilobase (kb) chromosomal fragment allowed the isolation of a 1.6-kb fragment that could complement the hemM mutation. Nucleotide sequence analysis of the 1.6-kb DNA fragment revealed an open reading frame that encodes a polypeptide of 426 amino acid residues, and the deduced molecular mass of this polypeptide is 46768 Da. The amino acid sequence shows a high degree of homology of the HemA protein, which is glutamyl-tRNA reductase, to other organisms. Thus, we examined the complementation test of the cloned gene from Xanthomonas with a hemA mutation of E. coli and found that the gene complemented the hemA mutation. These results suggest that the cloned gene is hemA and the gene from Xanthomonas also complements both hemA and hemM mutations, as in the case of the E. coli hemA. Correspondence to: Y. Murooka     

黄单胞菌(Xanthomonas campestris)XA5-5β-葡萄糖苷酶基因的克隆与表达

以黄单胞菌(Xanthomonas campestris)XA5-5为供体菌,广泛寄主质粒pRK404为载体,在大肠杆菌中克隆了一个β-葡萄糖苷酶基因,重组质粒pLZS1外源片段为1.1kb,将pLZS1接合导入黄单胞菌XA5-5,得到了克隆子XA5-5(pLZS1).以水杨苷为底物,XA5-5(pLZS1)的酶活性大大高于E.Coli JM83(pLZS1).并且质粒在XA5-5中能相对稳定地存在.初步结果表明,所克隆的基因编码的产物对于水杨苷底物有较强的亲和力,并可以在一定程度上降低XA5-5中酶与pNPG底物的亲和力,使其酶活减小.     

Volatiles and Nonvolatiles in Flourensia campestris Griseb. (Asteraceae), How Much Do Capitate Glandular Trichomes Matter?

The distribution and ultrastructure of capitate glandular trichomes (GTs) in Flourensia species (Asteraceae) have been recently elucidated, but their metabolic activity and potential biological function remain unexplored. Selective nonvolatile metabolites from isolated GTs were strikingly similar to those found on leaf surfaces. The phytotoxic allelochemical sesquiterpene (–)‐hamanasic acid A ((–)‐HAA) was the major constituent (ca. 40%) in GTs. Although GTs are quaternary ammonium compounds (QACs)‐accumulating species, glycine betaine was not found in GTs; it was only present in the leaf mesophyll. Two (–)‐HAA accompanying surface secreted products: compounds 4‐hydroxyacetophenone (piceol; 1 ) and 2‐hydroxy‐5‐methoxyacetophenone ( 2 ), which were isolated and fully characterized (GC/MS, NMR), were present in the volatiles found in GTs. The essential oils of fresh leaves revealed ca. 33% monoterpenes, 26% hydrocarbon‐ and 30% oxygenated sesquiterpenes, most of them related to cadinene and bisabolene derivatives. Present results suggest a main role of GTs in determining the volatile and nonvolatile composition of F. campestris leaves. Based on the known activities of the compounds identified, it can be suggested that GTs in F. campestris would play key ecological functions in plant‐pathogen and plant‐plant interactions. In addition, the strikingly high contribution of compounds derived from cadinene and bisabolene pathways, highlights the potential of this species as a source of high‐valued bioproducts.     

Biosynthesis of S-associated proteins following self- and cross-pollinations in Brassica campestris L. var. ‘T. 15’

Summary Homozygote plants for the (S) self-incompatibility gene have been produced in Brassica campestris L. var. T 15. Stigmas from plants designated S ₁ S ₁, S ₂ S ₂ and S ₄ S ₄ were extracted and their protein separated on an isoelectric focusing mini-gel. Differences were observed between proteins from stigmas of the three S-homozygous groups: S-genotype specific proteins were determined for S ₁ S ₁ and S ₂ S ₂ stigmas that were absent in the self-compatible S ₄ S ₄ stigmas. Carbon dioxide (CO₂), which is known to block the self-incompatibility reaction in Brassica, was applied to [³⁵S]-methionine unpollinated, self- and cross-pollinated stigmas to observe the effect of external CO₂ on the synthesis of these S-associated proteins. The results indicate that pollination triggers a dramatic reduction in protein synthesis in general and in the synthesis of S₂-associated protein after self-pollination in particular.     

Isolation and Molecular Characterization of RALF Like Gene BcRALF from Brassica campestris ssp.chinensis var.parachinensis

The rapid alkalinization factor (RALF) gene is a new found plant polypeptide signal molecule, wide spreading in higher plants. In this study BcRALF was cloned from Brassica campestris sspchinensis Makino varparachinensis based on BcMF14 (GenBank accession number EF523516) from Bcampestris ssp. chinensis var. communis cv. Aijiaohuang. The sequence of this gene was 273 bp (GU086228) and was identified as a rapid alkalization factor gene according to its high identity with Boleracea var botrytis BoRALF1 and Arabidopsis thaliana RALFL9. Protein characteristics and sequence structure were predicted, and moreover, many bioactive sites were found. The results showed that the characteristics of the BcRALF protein consistent with its category as a peptide signal molecule.