Chitinolytic activity of the acaropathogenic fungiHirsutella thompsoniiandHirsutella necatrix

1997 ◽  
Vol 43 (5) ◽  
pp. 440-446 ◽  
Author(s):  
Leonid Chernin ◽  
Aviva Gafni ◽  
Abraham Sztejnberg ◽  
Rita Mozes-Koch ◽  
Uri Gerson
Keyword(s):  
Spider Mite ◽  
Milk Powder ◽  
Sole Source ◽  
Tetranychus Cinnabarinus ◽  
Chitinolytic Activity ◽  
Chitinolytic Enzymes ◽  
Hirsutella Thompsonii ◽  
Proteolytic Activities ◽  
Acaropathogenic Fungi

Two isolates of the acaropathogenic fungus Hirsutella thompsonii (Nos. 255 and 414), and Hirsutella necatrix, were able to produce and excrete chitinolytic enzymes. A chitobiase of > 205 kDa was excreted by all fungi and a chitobiase of 112 kDa only by isolate 414. An endochitinase of 162 kDa was excreted by isolate 414 and two endochitinases of 66 and 38 kDa were excreted by isolate 255. Both H. thompsonii isolates produced chitinolytic enzymes only under inducible conditions, in the presence of colloidal chitin as the sole source of carbon. Hirsutella necatrix produced a chitobiase constitutively when grown in the presence of glucose. In addition to chitinolytic enzymes, the H. thompsonii isolates excreted proteolytic activities, including elastase, as well as α-esterase and α-amylase activities. Hirsutella necatrix was unable to use casein, milk powder, or elastin as the sole carbon source. The acaropathogenicity of these isolates was assayed on the carmine spider mite (Tetranychus cinnabarinus). Isolates 414 and 255 and H. necatrix killed ca. 80, 35, and 15%, respectively, of the infected mites. The role of chitinolytic and other enzymatic activities in the acaropathogenicity of these fungi is discussed.Key words: acaropathogenic fungi, Hirsutella, chitobiase, endochitinase, α-amylase.

Towards the Final Legitimation of the Party

2017 ◽  
Author(s):  
Piero Ignazi
Keyword(s):  
Twentieth Century ◽  
Great Britain ◽  
Political Parties ◽  
Political Party ◽  
Sole Source ◽  
The Political ◽  
Party Formation ◽  
Post War ◽  
Dominant Influence

Chapter 3 investigates the process of party formation in France, Germany, Great Britain, and Italy, and demonstrates the important role of cultural and societal premises for the development of political parties in the nineteenth century. Particular attention is paid in this context to the conditions in which the two mass parties, socialists and Christian democrats, were established. A larger set of Western European countries included in this analysis is thoroughly scrutinized. Despite discontent among traditional liberal-conservative elites, full endorsement of the political party was achieved at the beginning of the twentieth century. Particular attention is paid to the emergence of the interwar totalitarian party, especially under the guise of Italian and German fascism, when ‘the party’ attained its most dominant influence as the sole source and locus of power. The chapter concludes by suggesting hidden and unaccounted heritages of that experience in post-war politics.

Differential Roles of Three Different Upper Pathway Meta Ring Cleavage Product Hydrolases in the Degradation of Dibenzo- p -dioxin and Dibenzofuran by Sphingomonas wittichii RW1

2021 ◽  
Author(s):  
Thamer Y. Mutter ◽  
Gerben J. Zylstra
Keyword(s):  
Gene Knockout ◽  
Sole Source ◽  
Cleavage Product ◽  
Ring Cleavage ◽  
Catabolic Pathway ◽  
Double Knockout ◽  
Cleavage Enzyme ◽  
Sphingomonas Wittichii ◽  
Physiological Approach

Sphingomonas wittichii RW1 grows on the two related compounds dibenzofuran (DBF) and dibenzo- p -dioxin (DXN) as the sole source of carbon. Previous work by others (P.V. Bunz, R. Falchetto, and A.M. Cook. Biodegradation 4:171-8, 1993, doi: 10.1007/BF00695119) identified two upper pathway meta cleavage product hydrolases (DxnB1 and DxnB2) active on the DBF upper pathway metabolite 2-hydroxy-6-oxo-6-(2-hydroxyphenyl)-hexa-2,4-dienoate. We took a physiological approach to determine the role of these two enzymes in the degradation of DBF and DXN by RW1. Single knockouts of either plasmid located dbfB1 or chromosome located dbfB2 had no effect on RW1 growth on either DBF or DXN. However, a double knockout lost the ability to grow on DBF but still grew normally on DXN demonstrating that DbfB1 and DbfB2 are the only hydrolases involved in the DBF upper pathway. Using a transcriptomic-guided approach we identified a constitutively expressed third hydrolase encoded by the chromosomally located SWIT0910 gene. Knockout of SWIT0910 resulted in a strain that no longer grows on DXN but still grows normally on DBF. Thus the DbfB1 and DbfB2 hydrolases function in the DBF but not the DXN catabolic pathway and the SWIT0190 hydrolase functions in the DXN but not the DBF catabolic pathway. Importance S. wittichii RW1 is one of only a few strains known to grow on DXN as the sole course of carbon. Much of the work deciphering the related RW1 DXN and DBF catabolic pathways has involved genome gazing, transcriptomics, proteomics, heterologous expression, and enzyme purification and characterization. Very little research has utilized physiological techniques to precisely dissect the genes and enzymes involved in DBF and DXN degradation. Previous work by others identified and extensively characterized two RW1 upper pathway hydrolases. Our present work demonstrates that these two enzymes are involved in DBF but not DXN degradation. In addition, our work identified a third constitutively expressed hydrolase that is involved in DXN but not DBF degradation. Combined with our previous work, this means that the RW1 DXN upper pathway involves genes from three very different locations in the genome: an initial plasmid-encoded dioxygenase and a ring cleavage enzyme and hydrolase encoded on opposite sides of the chromosome.

scholarly journals Over-the-Counter Drugs and Complementary Medications Use among Children in Southern Italy

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Claudia Pileggi ◽  
Valentina Mascaro ◽  
Aida Bianco ◽  
Maria Pavia
Keyword(s):  
Positive Attitude ◽  
Southern Italy ◽  
Sole Source ◽  
Structured Interviews ◽  
Cross Sectional Survey ◽  
Community Based ◽  
Cross Sectional ◽  
Over The Counter ◽  
Source Of Information

The use of nonprescription medicines (NPDs) for children illnesses without a doctor’s suggestion can lead to unnecessary medication use and is not free of risks. The aim of our study was to examine attitudes and practice of parents towards NPDs use for their children. We also investigated the conditions that may predict NPDs use. A cross-sectional survey was conducted on parents of children attending Community Based Pediatrician (CBP) consultation and data were collected through structured interviews. Positive attitude on NPDs use was reported by 71.4% of parents, and 61.5% of them had administered NPDs in the previous 6 months. Antipyretic drugs were the most frequently used medication class without the supervision of the CBP. A positive attitude towards NPDs was significantly more frequent in parents who did not use the CBP as the sole source of information about drugs. The study demonstrated a widespread use of NPDs in children in our context, supported by a substantial positive attitude towards their safety. However, considering potential harms related to some NPDs and the finding that most parents rely on CBP advice, role of CBP on appropriate use of NPDs by parents should be emphasized.

scholarly journals The role of exochitinase type A1 in the fungistatic activity of the rhizosphere bacterium Paenibacillus sp. M4

2016 ◽  
Vol 68 (2) ◽  
pp. 451-459
Author(s):  
Urszula Jankiewicz ◽  
Maria Swiontek-Brzezinska
Keyword(s):  
Plant Pathogens ◽  
Chitinase Activity ◽  
Maximum Activity ◽  
Synergistic Action ◽  
Chitinolytic Activity ◽  
Fungistatic Activity ◽  
Rhizosphere Bacterium ◽  
Paenibacillus Sp ◽  
Growth Inhibiting

The aim of the study was to detect the activity and characterize potentially fungistatic chitinases synthesized by rhizosphere bacteria identified as Paenibacillus sp. M4. Maximum chitinolytic activity was achieved on the fifth day of culturing bacteria in a growth medium with 1% colloidal chitin. Analysis of a zymogram uncovered the presence of four activity bands in the crude bacterial extract. The used three-stage protein purification procedure resulted in a single band of chitinase activity on the zymogram. The purified enzyme exhibited maximum activity at pH 6.5 and temperature 45oC, and thermal stability at 40oC for 4 h. In terms of substrate specificity, it is an exochitinase (chitobiose). The amino acid sequence obtained after mass spectrometry showed similarity to chitinase A1 synthesized by Bacillus circulans. The M4 isolate demonstrated the highest growth inhibiting activity against plant pathogens belonging to the genera Fusarium, Rhizoctonia and Alternaria. Fungistatic activity, although to a somewhat lesser degree, was also demonstrated by purified chitinase. The obtained results confirm the participation of the studied exochitinase in antagonism towards pathogenic molds. However, the lower fungistatic effectiveness of the chitinases points to the synergistic action of different metabolites in biocontrol by these bacteria.

scholarly journals Phylogenetic and Functional Diversity of Saprolegniales and Fungi Isolated from Temperate Lakes in Northeast Germany

2021 ◽  
Vol 7 (11) ◽  
pp. 968
Author(s):  
Hossein Masigol ◽  
Jason Nicholas Woodhouse ◽  
Pieter van West ◽  
Reza Mostowfizadeh-Ghalamfarsa ◽  
Keilor Rojas-Jimenez ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Enzymatic Activity ◽  
Humic Substances ◽  
Plant Litter ◽  
Freshwater Ecosystems ◽  
Chitinolytic Activity ◽  
Ecological Implications ◽  
Eukaryotic Organisms

The contribution of fungi to the degradation of plant litter and transformation of dissolved organic matter (humic substances, in particular) in freshwater ecosystems has received increasing attention recently. However, the role of Saprolegniales as one of the most common eukaryotic organisms is rarely studied. In this study, we isolated and phylogenetically placed 51 fungal and 62 Saprolegniales strains from 12 German lakes. We studied the cellulo-, lignino-, and chitinolytic activity of the strains using plate assays. Furthermore, we determined the capacity of 10 selected strains to utilize 95 different labile compounds, using Biolog FF MicroPlates™. Finally, the ability of three selected strains to utilize maltose and degrade/produce humic substances was measured. Cladosporium and Penicillium were amongst the most prevalent fungal strains, while Saprolegnia, Achlya, and Leptolegnia were the most frequent Saprolegniales strains. Although the isolated strains assigned to genera were phylogenetically similar, their enzymatic activity and physiological profiling were quite diverse. Our results indicate that Saprolegniales, in contrast to fungi, lack ligninolytic activity and are not involved in the production/transformation of humic substances. We hypothesize that Saprolegniales and fungi might have complementary roles in interacting with dissolved organic matter, which has ecological implications for carbon cycling in freshwater ecosystems.

scholarly journals Role of the complex upstream region of the GDH2 gene in nitrogen regulation of the NAD-linked glutamate dehydrogenase in Saccharomyces cerevisiae.

1991 ◽  
Vol 11 (12) ◽  
pp. 6229-6247 ◽  
Author(s):  
S M Miller ◽  
B Magasanik
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Glutamine Synthetase ◽  
Nitrogen Source ◽  
Glutamate Dehydrogenase ◽  
Regulatory System ◽  
Sole Source ◽  
Lacz Fusion ◽  
Upstream Region ◽  
In Cells

We analyzed the upstream region of the GDH2 gene, which encodes the NAD-linked glutamate dehydrogenase in Saccharomyces cerevisiae, for elements important for the regulation of the gene by the nitrogen source. The levels of this enzyme are high in cells grown with glutamate as the sole source of nitrogen and low in cells grown with glutamine or ammonium. We found that this regulation occurs at the level of transcription and that a total of six sites are required to cause a CYC1-lacZ fusion to the GDH2 gene to be regulated in the same manner as the NAD-linked glutamate dehydrogenase. Two sites behaved as upstream activation sites (UASs). The remaining four sites were found to block the effects of the two UASs in such a way that the GDH2-CYC1-lacZ fusion was not expressed unless the cells containing it were grown under conditions favorable for the activity of both UASs. This complex regulatory system appears to account for the fact that GDH2 expression is exquisitely sensitive to glutamine, whereas the expression of GLN1, coding for glutamine synthetase, is not nearly as sensitive.

Variation in the microbiome of the spider mite Tetranychus truncatus with sex, instar and endosymbiont infection

2020 ◽  
Vol 96 (2) ◽  
Author(s):  
Yu-Xi Zhu ◽  
Zhang-Rong Song ◽  
Shi-Mei Huo ◽  
Kun Yang ◽  
Xiao-Yue Hong
Keyword(s):  
Spider Mite ◽  
Potential Role ◽  
Developmental Stages ◽  
Spider Mites ◽  
Rrna Gene ◽  
Associated Bacteria ◽  
Operational Taxonomic Units ◽  
Dominant Bacteria ◽  
The 16S Rrna Gene

ABSTRACT Most arthropod-associated bacterial communities play a crucial role in host functional traits, whose structure could be dominated by endosymbionts. The spider mite Tetranychus truncatus is a notorious agricultural pest harboring various endosymbionts, yet the effects of endosymbionts on spider mite microbiota remain largely unknown. Here, using deep sequencing of the 16S rRNA gene, we characterized the microbiota of male and female T. truncatus with different endosymbionts (Wolbachia and Spiroplasma) across different developmental stages. Although the spider mite microbiota composition varied across the different developmental stages, Proteobacteria were the most dominant bacteria harbored in all samples. Positive relationships among related operational taxonomic units dominated the significant coassociation networks among bacteria. Moreover, the spider mites coinfected with Wolbachia and Spiroplasma had a significantly higher daily fecundity and juvenile survival rate than the singly infected or uninfected spider mites. The possible function of spider-mite associated bacteria was discussed. Our results highlight the dynamics of spider mite microbiotas across different life stages, and the potential role of endosymbionts in shaping the microbiota of spider mites and improving host fitness.

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