Differences in the chitinolytic activity of mammalian chitinases on soluble and insoluble substrates

ABSTRACT To initiate invasion of the mosquito midgut,Plasmodium ookinetes secrete chitinolytic activity to penetrate the peritrophic matrix surrounding the blood meal. While ookinetes of the avian malaria parasite Plasmodium gallinaceum appear to secrete products of two chitinase genes, to date only one chitinase gene, PfCHT1, has been identified in the nearly completed Plasmodium falciparumstrain 3D7 genome database. To test the hypothesis that the single identified chitinase of P. falciparum is necessary for ookinete invasion, the PfCHT1 gene was disrupted 39 bp upstream of the stop codon. PfCHT1-disrupted parasites had normal gametocytogenesis, exflagellation, and ookinete formation but were markedly impaired in their ability to form oocysts inAnopheles freeborni midguts. Confocal microscopy demonstrated that the truncated PfCHT1 protein was present in mutant ookinetes but that the concentration of mutant PfCHT1 within the apical end of the ookinetes was substantially reduced. These data suggest that full-length PfCHT1 is essential for intracellular trafficking and secretion and that the PfCHT1 gene product is necessary for ookinetes to invade the mosquito midgut.

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Antifungal activity of chitinolytic bacteria isolated from airtight stored cereal grain

Canadian Journal of Microbiology ◽

10.1139/w97-141 ◽

1998 ◽

Vol 44 (2) ◽

pp. 121-127 ◽

Cited By ~ 17

Author(s):

Emma Frändberg ◽

Johan Schnürer

Keyword(s):

Streptomyces Coelicolor ◽

Fungal Growth ◽

Pathogenic Fungi ◽

Dual Culture ◽

Chitinolytic Activity ◽

Bacterial Colony ◽

Chitinolytic Bacteria ◽

Cereal Grain ◽

Antifungal Chitinase ◽

Streptomyces Halstedii

Chitinolytic bacteria are used as biocontrol agents of plant pathogenic fungi. They might also potentially inhibit growth of molds, e.g., Aspergillus spp. and Penicillium spp., in stored plant material. We isolated chitinolytic bacteria from airtight stored cereal grain and evaluated their antifungal capacity. Between 0.01 and 0.5% of the total aerobic counts were chitinolytic bacteria. Gram-negative bacteria, mainly Pseudomonadaceae, constituted approximately 80% of the chitinolytic population. Gram-positive isolates belonged predominantly to the Corynebacterium-Arthrobacter group, Streptomyces, and Bacillus. Chitinolytic activity was evaluated using culture filtrates from chitin-grown isolates as the release of p-nitrophenol from p-nitrophenyl N,N'-diacetylchitobiose and as the formation of clearing zones on chitin agar. No correlation between chitinolytic activity and antifungal effects was found when challenging Penicillium roqueforti Dierckx with bacterial isolates on chitin agar in a dual culture bioassay. Fungal hyphae frequently grew seemingly unaffected through the bacterial colony of a high chitinase producer on colloidal chitin. Only 4% of the chitinolytic isolates had strong effects on fungal growth. Among these, Streptomyces halstedii (K122) and Streptomyces coelicolor (K139) inhibited growth of a broad range of fungi. Streptomyces halstedii affected hyphal morphology and decreased the radial growth rate of all fungi investigated. These effects were not caused by volatile metabolites, polyenes, or N-carbamoyl-D-glucosamine.Key words: antifungal, chitinase, Streptomyces halstedii, Streptomyces coelicolor.

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

Archives of Biological Sciences ◽

10.2298/abs150619138j ◽

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.

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

Journal of Fungi ◽

10.3390/jof7110968 ◽

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.

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Immobilization of Aeromonas bivalvium PT2 Cells with Alginate and Measurement of Chitinolytic Activities

E3S Web of Conferences ◽

10.1051/e3sconf/202014703020 ◽

2020 ◽

Vol 147 ◽

pp. 03020

Author(s):

Dita P. Saputri ◽

Ustadi

Keyword(s):

Bacterial Cell ◽

Cell Immobilization ◽

Chitinase Activity ◽

Nutrient Broth ◽

Chitinolytic Activity ◽

Immobilized Bacteria ◽

Chitinolytic Bacteria ◽

Bacterial Immobilization ◽

The Stability ◽

Bacterial Cell Immobilization

Aeromonas bivalvium is one of the chitinolytic bacteria that able to degrade chitin into its derivatives. These bacteria can only be used once during the fermentation process, which is less profitable to be applied in industrial scale. This limitation can be solved by bacterial immobilization method. This study aimed to determine the effect of bacterial cell immobilization on chitinolytic activity and to determine the stability of the immobilized bacteria during repeated usage. Bacterial cell immobilization was carried out by entrapment method with 1% sodium alginate matrix. Immobilized bacteria was cultured in two different mediums, namely nutrient broth (NB) and nutrient broth (NB) added with colloidal chitin (NB + K). Tests for chitinolytic activity were carried out in bacteria. In addition, the stability of immobilized bacteria was also tested for chitinolytic activity with repeated removal and use. The result shows that the effectiveness of immobilization on average is 91.8%. Immobilization did not significantly affect chitinolytic activity when compared with bacteria without immobilization. Immobilized bacteria in this study has similar performance as bacteria without immobilization. The results of the stability tests including chitinase activity and NAG released indicated a significant decline during repeated usage with maximum usage of three times.

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