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Optimization of growth conditions for xylanase production by Aspergillus niger in solid state fermentation

100%

Kavya V., Padmavathi T.

Polish Journal of Microbiology

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2009

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tom 58

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nr 2

125-130

The objectives of the present study were isolation, identification and characterization of xylanase producing fungi, optimization of medium composition and cultural conditions for xylanase enzyme production using cheaper sources. The fungal strains were isolated from garden soil by serial dilution technique and Aspergillus niger was identified and isolated in pure form. In conformation screening by congo red test, based on the reddish zone of enzyme activity formation in oat spelt xylan agar plates, A. niger was selected and optimized for xylanase enzyme production in solid state fermentation using cheaper sources like wheat bran, rice bran, soya bran, ragi bran and saw dust. Maximum enzyme activity was observed in wheat bran (9.87 U/ml). The use of wheat bran as a major carbon source is particularly valuable because oat spelt xylan or birch wood xylan are more expensive. The effects of time course, incubation substrate, inoculum size, moisturizing agent, moisture content, temperature and volume of fermentation medium on the production of xylanase were studied. The maximum xylanase production (12.65 U/ml) was observed at optimized condition, incubation temperature of 28°C after 6 days of incubation period while minimum production (9.38 U/ml) at unoptimized condition. The maximum production of enzyme was found to be in wheat bran when the volume of fermentation medium was kept as 10 g/250 ml conical flasks, with mineral solution as moisturizing agent and moisture ratio 1:0.7. Thus the present study proved that the fungal strain A. niger used is highly potential and useful for xylanase production.

2

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The use of a 2-aminoethylphosphonate by the mesophilic Penicillium commune strain

86%

Stosiek N., Klimek-Ochab M.

BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology

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2018

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tom 99

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nr 4

3

GrxS17, a multidomain glutaredoxin acting in meristems

86%

Riondet C., Bashandy T., Rey P., Gaymard F., Vignols F., Rouhier N., Reichheld J.

BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology

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2013

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tom 94

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nr 2

4

Structure of the arginase coding gene and its transcript in Aspergillus nidulans

86%

Borsuk P., Dzikowska A., Empel J., Grzelak A., Grzeskowiak R., Weglenski P.

Acta Biochimica Polonica

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1999

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tom 46

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nr 2

The arginase structural gene (agaA) from Aspergillus nidulans has been cloned and characterised. Depending on the growth conditions of the mycelium, transcripts of this gene have different 5'ends. These differences could result either from the presence of multiple transcription initiation sites or from differential processing of mRNA. The agaA mRNA has a long 5'UTR with a potentially complex secondary structure. Putative arginine binding aptamers were found in this UTR suggesting interesting possibilities for regulation of the agaA expression.

5

Chromate reduction by cell-free extract of Bacillus firmus KUCr1

72%

Sau G. B., Chatterjee S., Mukherjee S. K.

Polish Journal of Microbiology

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2010

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tom 59

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nr 3

Microbial enzymatic reduction of a toxic form of chromium [Cr(VI)] has been considered as an effective method for bioremediation of this metal. This study reports on the in vitro reduction of Cr(VI) using cell-free extracts from a Cr(VI) reducing Bacillusfirmus KUCr1 strain. Chromium reductase was found to be constitutive and its activity was observed both in soluble cell fractions (S₁₂and S₁₅₀) and membrane cell fraction (P₁₅₀). The reductase activity of S₁₂ fraction was found to be optimal at 40 μM Cr(VI) with enzyme concentration equivalent to 0.493 mg protein/ml. Enzyme activity was dependent on NADH or NADPH as electron donor; optimal temperature and pH for better enzyme activity were 70°C and 5.6, respectively. The Km value of the reductase was 58.33 μM chromate having a Vmax of 11.42 μM/min/mg protein. The metabolic inhibitor like sodium azide inhibited reductase activity of membrane fraction of the cell-free extract. Metal ions like Cu²⁺, Co²⁺, Ni²⁺ and As³⁺ stimulated the enzyme but others, such as Ag⁺, Hg²⁺, Zn²⁺, Mn²⁺, Cd²⁺ and Pb²⁺, inhibited Cr(VI) reductase activity.

6

Seasonal variations of oscillation and vibration parameters of Acer platanoides

72%

Netsvetov M., Nikulina V.

Dendrobiology

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2010

|

tom 64

This article describes an investigation into the seasonal variations of frequency, damping ratio and amplitude of swaying and vibration of Norway maple Acer platanoides L. The study was carried through a series of pull andrelease experiments in situ andon branches in the laboratory using an artificial air flow. It was foundthat foliatedtrees hada natural sway frequency that was on average 1.6±0.2 times greater than in the out-of-leaf state. In contrast, the damping ratio of maple increased by 1.5±0.3 times in the summer period. The stem swaying initiatedvibrations, i.e. elastic wave, in the roots with frequencies in the range of 45–50 Hz. Laboratory tests showed that the vibration amplitude of branches depended linearly on leaf mass for an air flow velocity of 1.94 m/s.

7

The effect of agitation on pullulan production by a white mutant Aureobasidium pullulans B-1 in batch culture

72%

Gniewosz M., Krasniewska K., Synowiec A.

Electronic Journal of Polish Agricultural Universities. Series: Biotechnology

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2013

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tom 16

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nr 2

8

Dynamics of non-structural carbohydrates in Pinus pallasiana D. Don needles under different forest growth conditions of ravine anti-erosion plantations

72%

Bessonova V., Yakovlieva-Nosar S.

Folia Forestalia Polonica. Series A . Forestry

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2022

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tom 64

|

nr 1

9

Evaluation of yeast cell vitality using different fluorescent dyes

72%

Kregiel D., Berlowska J.

Zeszyty Naukowe. Politechnika Łódzka. Chemia Spożywcza i Biotechnologia

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2009

|

tom 73

5-14

10

Interactions of Yersinia enterocolitica biotype 4 and 1A strains with macrophages in vitro

72%

Kot B., Stepinska M., Jakubczak A., Trafny E. A.

Medycyna Weterynaryjna

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2007

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tom 63

|

nr 04

416-420

The interaction of Y. enterocolitica strains belonging to 4 and 1A biotypes with RAW264.7 murine macrophage- like cell monolayers was studied. Y. enterocolitica strains from humans and pigs were characterized in terms of their internalization and survival within RAW264.7 cell monolayers and their ability to escape from the cells. Y. enterocolitica biotype 4 strains invaded macrophage cell monolayers to a significantly higher degree than biotype 1A strains. However, biotype 1A strains exhibited a greater level of survival in macrophages than biotype 4 strains. All Y. enterocolitica strains tested demonstrated the ability to escape from macrophages. The mechanisms that allow Y. enterocolitica biotype 1A to survive within macrophages may contribute to the virulence of these organisms

11

Effect of suboptimal nutrient conditions on nitrogen, photosynthetic and symbiotic status of mycorrhized maize

72%

Paluch E., Polcyn W., Lehmann T., Scierzynska M.

BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology

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2013

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tom 94

|

nr 3

12

Highly thermostable exopolysaccharide produced by the moderately halophilic bacterium isolated from a man-made young salt lake in Romania

72%

Cojoc R., Merciu S., Oancea P., Pincu E., Dumitru L., Enache M.

Polish Journal of Microbiology

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2009

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tom 58

|

nr 4

289-294

Halophilic bacterial strains isolated from a man-made salt lake in Romania produce a specific exopolysaccharide. This product is synthesized under both static and stirring conditions, and the yield of this exoploysaccharide depends on the composition of the culture medium. The highest amount of polymer was obtained in the presence of casamino acids and yeast extract, under stirring conditions. This polymer has high thermostability, with a melting point at 207°C. The melting process is associated with the thermal degradation of the compound. This polymer is characterized by maximum absorbtion at 260 nm and fluorescence emission at 530 nm. The FT-IR analysis of the polymer revealed the presence of a saccharide structure and of amine and sulfate groups throughout the sugar backbone.

13

Ultrasonic influence on convection in the melts

72%

Kozhemyakin G., Degtyareva A.

Teka Komisji Motoryzacji i Energetyki Rolnictwa

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2010

|

tom 10A

14

SDS-PAGE heat-shock protein profiles of environmental Aeromonas strains

72%

Osman K. M., Amin Z. M. S., Aly M. A. K., Hassan H., Soliman W. S.

Polish Journal of Microbiology

|

2011

|

tom 60

|

nr 2

Aeromonas microorganisms normally grow at temperatures between 5°C and 45°C and therefore should have high thermotolerance. Thus it was of interest to find out whether A. hydrophila, A. caviae and A. veronii biovar sobria serovars respond to abrupt temperature changes with a heat shock-like response. To this end the present study was undertaken to determine whether Aeromonas species exhibits a heat shock response to different temperatures and time factors. The response of Aeromonas serovars to 24 h and 48 h of thermal stress at 25°C, 42°C and 50°C involved the synthesis of 12–18 heat shock proteins (HSPs) bands with molecular weights ranging between 83.5–103.9 kDa in the high HSP molecular mass and 14.5–12.0 as low molecular mass HSP. Electrophoretic analysis of the HSPs showed that the serovars do not cluster very tightly and also that they are distinct from each other.

15

On the role of bacterial inoculum growth conditions on nitrate denitrification pathway

72%

Blaszczyk M., Jastrzebska E., Mycielski R.

Acta Microbiologica Polonica

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1995

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tom 44

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nr 2

16

A method for isolation of plasmid DNA replication intermediates from unsynchronized bacterial cultures for electron microscopy analysis

72%

Srutkowska S., Konopa G., Wegrzyn G.

Acta Biochimica Polonica

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1998

|

tom 45

|

nr 1

Electron microscopy is a powerful technique for analysis of DNA replication intermediates. However, isolation of replicating DNA molecules from living cells is tricky and difficult, especially in the case of small DNA molecules (such as bacterial plasmids) whose initiation of replication is not easily synchronized. Here a relatively simple and rapid method for efficient isolation of replicating plasmid molecules from unsynchronized Escherichia coli cultures is described. The efficiency of this procedure is high enough for electron microscopy analysis of plasmid replication intermediates appearing in living cells in normal growth conditions. Under optimal conditions, using standard procedures of isolation of plasmid DNA, it is possible to achieve a content of only as few as 0.02 percent of replication intermediates in a plasmid DNA sample. The described method allowed us to enrich up to 100-fold the fraction of replication intermediates suitable for microscopic analysis among all plasmid molecules.

17

Cell surface hydrophobicity of Bacillus spp. as a function of nutrient supply and lipopeptides biosynthesis and its role in adhesion

72%

Czaczyk K., Bialas W., Myszka K.

Polish Journal of Microbiology

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2008

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tom 57

|

nr 4

Cell surface hydrophobicity (CSH) is recognised as a important factor in microbial adhesion to solid surfaces. Growth conditions have been found to determine the synthesis of extracellular molecules by microorganisms. It has major consequences in modification of bacterial surface properties and consequently, in bacterial adhesion to solid surfaces. In this paper, CSH properties of Bacillus spp. depending on the nutrient supply and lipopeptide biosynthesis and its role in bacterial adhesion to solid surfaces were investigated. The obtained results indicate that the examined factors (nitrogen and carbon availability) influence the CSH of Bacillus spp. cells. In most variants of the experiments the role of nutrient supply in adhesion process was characteristic for species. The strongest effect was observed for peptone concentration (P<0.001). A decrease of CSH was noticed in optimal nitrogen availability (10 g/l) and it was connected with maximum yield of surfactin biosynthesis. The highest values of CSH of examined Bacillus spp. strains were observed under nitrogen starvation and in excess of carbon source. In these conditions the adhesion to stainless steel surface was more extensive.

18

Hemagglutinins of Beauveria bassiana strains: the effect of growth conditions on their production

72%

Peczynska-Czoch W., Wieczorek J., Urbanczyk M. J.

Archivum Immunologiae et Therapiae Experimentalis

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1992

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tom 40

|

nr 5-6

19

The unique cyclopropane fatty acid composition of rhizospheral Pseudomonas fluorescent isolates

72%

Zarnowski R., Pietr S. J., Quilez J. F., Cabrera E., Barrero A. F.

Cellular and Molecular Biology Letters

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2000

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tom 05

|

nr 2

9,10-methylenehexadecanoic acid was found to be the main and sole constituent of the cyclopropane fatty acid (CFA) pool of five Pseudomonas fluorescent strains. Our findings have shown that all the studied isolates of plant-growth promoting rhizospheral fluorescent pseudomonads have qualitatively identical CFA profiles, even though they have the ability to make use of distinct carbon sources and show different plant root colonisation ability. This report suggests that the preservation of the proper CFA composition in biomembranes may be crucial for rhizobacteria adaptation to the fluctuation of physicochemical conditions in the rhizosphere.

20

Induction of CLP proteins is crucial for the cold acclimation process in the cyanobacterium Synechococcus sp. strain PCC 7942

72%

Porankiewicz J., Schelin J., Clarke A. K.

Biological Bulletin of Poznań. Supplement

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1997

|

tom 34

Ograniczanie wyników

Optimization of growth conditions for xylanase production by Aspergillus niger in solid state fermentation

The use of a 2-aminoethylphosphonate by the mesophilic Penicillium commune strain

GrxS17, a multidomain glutaredoxin acting in meristems

Structure of the arginase coding gene and its transcript in Aspergillus nidulans