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1.
Matías Maggi Natalia Damiani Sergio Ruffinengo David De Jong Judith Principal Martín Eguaras 《Experimental & applied acarology》2010,50(3):269-279
We undertook a field study to determine whether comb cell size affects the reproductive behavior of Varroa destructor under natural conditions. We examined the effect of brood cell width on the reproductive behavior of V. destructor in honey bee colonies, under natural conditions. Drone and worker brood combs were sampled from 11 colonies of Apis mellifera. A Pearson correlation test and a Tukey test were used to determine whether mite reproduction rate varied with brood cell
width. Generalized additive model analysis showed that infestation rate increased positively and linearly with the width of
worker and drone cells. The reproduction rate for viable mother mites was 0.96 viable female descendants per original invading
female. No significant correlation was observed between brood cell width and number of offspring of V. destructor. Infertile mother mites were more frequent in narrower brood cells. 相似文献
2.
The lipase Lip2 of the edible basidiomycete, Pleurotus sapidus, is an extracellular enzyme capable of hydrolysing xanthophyll esters with high efficiency. The gene encoding Lip2 was expressed
in Escherichia coli TOP10 using the gene III signal sequence to accumulate proteins in the periplasmatic space. The heterologous expression under
control of the araBAD promoter led to the high level production of recombinant protein, mainly as inclusion bodies, but partially
in a soluble and active form. A fusion with a C-terminal His tag was used for purification and immunochemical detection of
the target protein. This is the first example of a heterologous expression and periplasmatic accumulation of a catalytically
active lipase from a basidiomycete fungus. 相似文献
3.
Dana Bernátová 《Biologia》2008,63(2):175-176
The paper brings information on an isolated occurrence and morphological characters of Carex × involuta and C. juncella populations in the Vel’ká Fatra Mts. Their presence has been known neither from the territory of Slovakia nor from the whole
Western Carpathians till now. 相似文献
4.
5.
G. I. Naumov M. Yu. Shalamitskiy E. S. Naumova 《Doklady. Biochemistry and biophysics》2016,467(1):89-91
Using yeast genome databases and literature data, we have conducted a phylogenetic analysis of pectinase PGU genes from Saccharomyces strains assigned to the biological species S. arboricola, S. bayanus (var. uvarum), S. cariocanus, S. cerevisiae, S. kudriavzevii, S. mikatae, S. paradoxus, and hybrid taxon S. pastorianus (syn. S. carlsbergensis). Single PGU genes were observed in all Saccharomyces species, except S. bayanus. The superfamily of divergent PGU genes has been documented in S. bayanus var. uvarum for the first time. Chromosomal localization of new PGU1b, PGU2b, and PGU3b genes in the yeast S. bayanus var. uvarum has been determined by molecular karyotyping and Southern hybridization. 相似文献
6.
Chaoyi Liu Huanwen Xu Jing Jiang Sui Wang Guifeng Liu 《Plant Cell, Tissue and Organ Culture》2018,132(1):191-199
7.
8.
Despite the widespread distribution of Astyanax bockmanni in streams from Upper Paraná River system in central, southeastern, and southern Brazil, just recently, it has been identified
as a distinct Astyanax species. Cytogenetic studies were performed in two populations of this species, revealing conservative features. A. bockmanni shows 2n = 50 chromosomes, a karyotypic formula composed of 10 M + 12SM + 12ST + 16A and multiple Ag-NORs. Eight positive signals
in subtelocentric/acrocentric chromosomes were identified by fluorescent in situ hybridization (FISH) with 18S rDNA probes.
After FISH with 5S rDNA probes, four sites were detected, comprising the interstitial region of a metacentric pair and the
terminal region on long arms of another metracentric pair. Little amounts of constitutive heterochromatin were observed, mainly
distributed at distal region in two chromosomal pairs. Additionally, heterochromatin was also located close to the centromeres
in some chromosomes. No positive signals were detected in the chromosomes of A. bockmanni by FISH with the As-51 satellite DNA probe. The studied species combines a set of characteristics previously identified in
two different Astyanax groups. The chromosomal evolution in the genus Astyanax is discussed. 相似文献
9.
Dhanya Gangadharan Priya Ramachandran Gunasekaran Paramasamy Ashok Pandey K. Madhavan Nampoothiri 《Biologia》2010,65(3):392-398
Raw starch is the most abundant source of glucose in the world. Therefore, finding enzymes capable of digesting raw starch
would find high industrial demand. The α-amylase gene of Bacillus amyloliquefaciens ATCC 23842 was amplified, cloned and overexpressed in Escherichia coli BL21 (DE3) cells. The recombinant enzyme was purified to apparent homogeneity using ion exchange and gel filtration chromatography.
The raw-starch digestibility of the purified enzyme was characterized by studying the hydrolysis and adsorption rate on a
variety of raw starches (potato, cassava, corn, wheat and rice). The raw-starch digestion was further confirmed by scanning
electron microscopy studies, which revealed an effective rate of hydrolysis. The kinetic studies revealed a relatively low
K
m of 2.76 mg/mL, exhibiting high affinity towards the soluble starch as the most preferred substrate and the inhibition kinetic
studies revealed a high K
i value (350 mM). 相似文献
10.
Hubert J Dolecková-Maresová L Hýblová J Kudlíková I Stejskal V Mares M 《Experimental & applied acarology》2005,35(4):281-291
The stored-product mites are the most abundant and frequent group of pests living on the stored food products in Europe. They endanger public health since they produce allergens and transmit mycotoxin-producing fungi. Novel acaricidal compounds with inhibitory effects on the digestive enzymes of arthropods are a safe alternative to the traditional neurotoxic pesticides used for control of the stored-product pests. In this work, we explored the properties of acarbose, the low molecular weight inhibitor of -amylases (AI), as a novel acaricide candidate for protection of the stored products from infestation by Acarus siro (Acari: Acaridae). In vitro analysis revealed that AI blocked efficiently the enzymatic activity of digestive amylases of A. siro, and decreased the physiological capacity of mites gut in utilizing a starch component of grain flour. In vivo experiments showed that AI suppressed the population growth of A. siro. The mites were kept for three weeks on experimental diet enriched by AI in concentration range of 0.005 to 0.25%. Population growth of A. siro was negatively correlated with the content of AI in the treated diet with a half-population dose of 0.125%. The suppressive effect of AIs on stored-product mites is discussed in the context of their potential application in GMO crops 相似文献
11.
Abdul Ghaffar Sher Afzal Khan Zahid Mukhtar Muhammad Ibrahim Rajoka Farooq Latif 《Molecular biology reports》2011,38(5):3227-3233
We studied heterologous expression of xylanase 11A gene of Chaetomium thermophilum in Pichia pastoris and characterized the thermostable nature of the purified gene product. For this purpose, the xylanase 11A gene of C. thermophilum was cloned in P. pastoris GS115 under the control of AOX1 promoter. The maximum extracellular activity of recombinant xylanase (xyn698: gene with intron) was 15.6 U ml−1 while that of recombinant without intron (xyn669) was 1.26 U ml−1 after 96 h growth. The gene product was purified apparently to homogeneity level. The optimum temperature of pure recombinant
xylanase activity was 70°C and the enzyme retained its 40.57% activity after incubation at 80°C for 10 min. It exhibited quite
lower demand of activation energy, enthalpy, Gibbs free energy, entropy, and xylan binding energy during substrate hydrolysis
than that required by that of the donor, thus indicating its thermostable nature. pH-dependent catalysis showed that it was
quite stable in a pH range of 5.5–8.5. This revealed that gene was successfully processed in P. pastoris and remained heat stable and may qualify for its potential use in paper and pulp and animal feed applications. 相似文献
12.
Marie Kempf Jane Cottin Patricia Licznar Corinne Lefrançois Raymond Robert Véronique Apaire-Marchais 《Mycopathologia》2009,168(2):73-77
Candida albicans is the most important cause of systemic fungal infection in immunocompromised humans. Candidiasis is often initiated by the
adherence and the colonization of inert surfaces such as peripheral venous catheters, central catheters, prosthetic cardiac
valves, and other prostheses. We have studied the early stage of adherence and have shown that the disruption of C. albicans
IFF4 gene encoding a GPI-anchor protein, led to a decrease of adherence of the germ tubes to plastic. Here, we demonstrated the
role of the IFF4 gene in adherence to silicone catheter, as well as in virulence using a murine model of disseminated candidiasis. The iff4 Δ null mutant showed both a decrease of adherence to silicone catheter and a reduction of virulence. This work presents evidence
for the importance of the IFF4 gene in host-fungal interaction. 相似文献
13.
14.
Summary. 2H-Pyran-2-ones 1 were transformed with various hydrazines into (E)- or (Z)-α,β-didehydro-α-amino acid (DDAA) derivatives 4 (and 7) containing a highly substituted pyrazolyl moiety attached at the β-position. With heterocyclic hydrazines, the products 4 were accompanied also by decarboxylated enamines E-6. In order to separate (E/Z)-mixtures of acids, they were transformed to the corresponding methyl esters 9 and 10 by the application of diazomethane. Catalytic hydrogenation under high pressures with Pd/C as a catalyst resulted in the formation
of racemic alanine derivatives 11.
Received January 29, 2002 Accepted May 27, 2002 Published online December 18, 2002
RID="*"
ID="*" Dedicated with deep respect to Professor Waldemar Adam on the occasion of his 65th birthday.
Acknowledgements We thank the Ministry of Education, Science and Sport of the Republic of Slovenia for the financial support (P0-0503-103).
Dr. B. Kralj and Dr. D. Žigon (Center for Mass Spectroscopy, “Jožef Stefan” Institute, Ljubljana, Slovenia) are gratefully
acknowledged for the mass measurements.
Authors' address: Prof. Marijan Kočevar, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, SI-1000 Ljubljana,
Slovenia, E-mail: marijan.kocevar@uni-lj.si 相似文献
15.
Of the genes involved in galactose metabolism, GAL7, GAL10, and GAL1 are tightly linked in this order on chromosome II in Saccharomyces cerevisiae. While several species of the order Saccharomycetales have similar gene organization, Kazachstania naganishii is unique, in which GAL7 and GAL1 are close to each other whereas GAL10 is substantially apart from them on chromosome XI. In this study, we inserted the recognition sequence of I-SceI homing-endonuclease into GAL10 and also into the intervening segment of GAL7-GAL1. By cleaving chromosome DNA of the gene-manipulated strain with I-SceI, we obtained evidence that chromosome XI (610 kbp) was replaced with three fragments (305, 265, and 40 kbp). Using appropriate
probes, we further found that GAL10 was about 40 kbp apart from the GAL7-GAL1 cluster and that orientation of GAL10 was reversed comparing to the S. cerevisiae counter part. We, therefore, contend that comparison of the organization of the GAL cluster among Saccharomycetales is of importance to elucidate evolution of chromosomes and that the experimental scheme developed
in this study is useful for this line of investigation. 相似文献
16.
Verónica L. Fuentes Dror L. Angel Keith M. Bayha Dacha Atienza Dor Edelist Cesar Bordehore Josep-Maria Gili Jennifer E. Purcell 《Hydrobiologia》2010,645(1):23-37
Blooms of the invasive ctenophore, Mnemiopsis leidyi, occurred in 2009 along the Mediterranean Sea coasts of Spain and Israel. This voracious zooplanktivore spread throughout
the Black Sea basin after its introduction in the early 1980s, throughout northern European coastal waters, and now occurs
throughout the Mediterranean Sea. M. leidyi occurred throughout the summer along the entire Catalan Spanish and Israeli coasts in 2009. Those locations had high temperatures
(18–26°C) and salinities (37–38) during the blooms. The patterns of abundance of large jellyfish along the Catalan coast were
unusual in 2009, with low numbers during July, August, and September when ctenophores were abundant. Small populations of
those potential predators and food competitors of M. leidyi could have contributed to the ctenophore bloom. The identity of the ctenophores from Spain and Israel was confirmed as M. leidyi by molecular analysis based on DNA sequencing of the nuclear internal transcribed spacer (ITS) regions. This is the first
molecular confirmation of M. leidyi in the Mediterranean Sea. Most ctenophores had an ITS genotype previously found in M. leidyi from other invaded regions (the Black, Azov, and Mediterranean seas), as well as native regions in the United States, suggesting
common ancestry. Based on the circulation patterns of Mediterranean surface waters and shipping activities, we conclude that
the spread of M. leidyi in the Mediterranean probably resulted from re-introductions by ballast water transport and subsequent distribution by currents.
We also conclude that the near-simultaneous blooms in opposite ends of both the Mediterranean basins indicate that M. leidyi is resident around the Mediterranean. We discuss environmental conditions, food, and predators of M. leidyi in both regions that would influence the future effects of this voracious consumer on the pelagic food web of the Mediterranean
Sea. 相似文献
17.
Alexandre Favarin Somera Marita Gimenez Pereira Luis Henrique Souza Guimarães Maria de Lourdes Teixeira de Moraes Polizeli Héctor Francisco Terenzi Rosa Prazeres Melo Furriel João Atílio Jorge 《Journal of microbiology (Seoul, Korea)》2009,47(3):270-276
Aspergillus versicolor grown on xylan or xylose produces two β-xylosidases with differences in biochemical properties and degree of glycosylation. We investigated the alterations in the
biochemical properties of these β-xylosidases after deglycosylation with Endo-H or PNGase F. After deglycosylation, both enzymes migrated faster in PAGE or
SDS-PAGE exhibiting the same Rf. Temperature optimum of xylan-induced and xylose-induced β-xylosidases was 45°C and 40°C, respectively, and 35°C after deglycosylation. The xylan-induced enzyme was more active at
acidic pH. After deglycosylation, both enzymes had the same pH optimum of 6.0. Thermal resistance at 55°C showed half-life
of 15 min and 9 min for xylose- and xylan-induced enzymes, respectively. After deglycosylation, both enzymes exhibited half-lives
of 7.5 min. Native enzymes exhibited different responses to ions, while deglycosylated enzymes exhibited identical responses.
Limited proteolysis yielded similar polypeptide profiles for the deglycosylated enzymes, suggesting a common polypeptide core
with differential glycosylation apparently responsible for their biochemical and biophysical differences. 相似文献
18.
Black nightshades are a group of species best known for their ‘poisonous’ or noxious weedy reputation. It is not so well known
that species of this group serve as emerging food source in many countries worldwide especially in the African continent.
Despite the fact that the section has recently been studied extensively, taxonomy is still unsettled and debated because of
inter- and intraspecific hybridization, phenotypic plasticity and polyploidization. In this study we analyze the genetic relationships
among diploid, tetraploid and hexaploid species of sect. Solanum, which have possibly taken part in the formation of Solanum nigrum, utilizing multi-locus (SCoT, ISSR) markers combined with chloroplast trnL-F sequence data and morphological characters. We scored 51 morphological characters united with SCoT (171), ISSR (224) and
trnL-F (1042), for simultaneous analysis of 49 terminals and 1488 characters. The topology of the tree is concordant with the results
of the network analysis. In the phylogenetic networks, all the accessions of the diploid species shared a split with all of
the polyploid species. This reflected a high portion of shared ISSR and SCoT bands between diploids and polyploids. In addition,
a strong split divided the diploid species. The history of S. nigrum might be reticulate with hybrid speciation playing an important rule. Genetically differentiated diploids in few combinations
have created a series of genetically distinct polyploid populations. The insufficient isolation that permitted further recombination
between ancient polyploids and diploids have resulted in high level of genotypic and phenotypic polymorphism. This high level
of novel genomic variability obviously enabled species to succeed in their new environment. 相似文献
19.
The reactions of isolates of Phytophthora cactorum, P. nicotianae and P. × pelgrandis to metalaxyl, mancozeb, dimethomorph, streptomycin and chloramphenicol were tested to obtain information about the variability of resistance in these pathogens. Distinct genetic groups showed significant differences in resistance to all tested substances except streptomycin. In response to streptomycin, the growth inhibition rates of distinct groups did not differ significantly. The most remarkable differences were detected in the reactions to chloramphenicol and metalaxyl. Discriminant analysis evaluating the effect of all substances confirmed the differences among the groups, which are in agreement with the differences revealed by earlier DNA analyses. 相似文献
20.
Yanqiong Guo Chunli Feng Huanlu Song Zhaoyue Wang Qing Ren Ran Wang 《World journal of microbiology & biotechnology》2011,27(12):2807-2812
γ-Decalactone, an important flavor compound, can be produced by Yarrowia lipolytica, but the yield is poor because of lactone degradation by enzyme Aox3 (POX3 gene encoded). A yeast strain Yarrowia lipolytica TA1 of high γ-decalactone yield was constructed by integrating copper-resistance gene CRF1 from Yarrowia lipolytica into the locus of POX3 genes. After being cultured in shake-flask at 28°C for 90 h, TA1 reached a γ-decalactone yield of 0.531 g/l (highest at 63 h),
being 2.9 times higher than that of Yarrowia lipolytica As2.1045 (0.194 g/l, highest at 57 h). It was free of heterologous DNA sequences and drug-resistance genes and could be safely
used in γ-decalactone production. And this work may throw a new light on addressing the problems in commercial fragrance manufacture. 相似文献