scholarly journals Biochemical Characterization of Cellulolitic Bacteria From Mangroves Weathered Wood In Muntok Sub district, West Bangka Regency

Author(s):  
Ardiansyah Kurniawan ◽  
Asep Awaludin Prihanto ◽  
Suci Puspita Sari ◽  
Andi Kurniawan ◽  
Euis Asriani ◽  
...  

Acceleration of wood weathering in the mangrove area is possible with the role of cellulolytic bacteria. Cellulolytic bacteria producing cellulase enzymes are needed by the animal feed and agriculture industries. Mangroves in Muntok Subdistrict undergo a process of adaptation to environmental changes due to tin mining, including microorganisms. Exploration of new species and strains of cellulolytic bacteria in miningaffected mangroves is needed to enrich the collection and its potential use for human needs. This study aims to identify cellulolytic bacteria in mangrove weathered wood in Muntok District, West Bangka Regency through isolation, screening, and biochemical characterization. Three sampling locations, namely Sukal Mangrove, Peltim Mangrove, and Tembelok Mangrove result 22 bacterial isolates with 11 isolates showing the ability of cellulose degradation in qualitative tests using Lugol. The biochemical characterization of bacterial isolates with the greatest cellulose degradation was directed towards Citrobacter freundii and Vibrio alginolyticus in samples of Sukal Mangrove and Actinomyces bovis in isolates from Peltim Mangrove.

2020 ◽  
Vol 4 (1) ◽  
pp. 48-54
Author(s):  
Wardha Maulidya Pratiwi ◽  
Rana Yumna Nabila ◽  
Heliza Amalini ◽  
Guntur Trimulyono

The purpose of this study was to obtain cellulolytic bacterial isolates isolated from leaf litter in absorption holes biopori FMIPA Unesa and obtain the most optimal cellulolytic bacterial isolates in cellulose degradation. This research was an observational study and the data were analyzed descriptively. Stages of the study began with bacterial isolation, cellulolytic ability testing, and characterization of cellulolytic bacterial isolates. Bacterial isolation was carried out by the pour plate method, isolation was carried out by the streak plate method, cellulolytic testing was carried out using Carboxy Methyl Cellulose media which was given Congo red 1%. While the isolation characterization was done morphologically, physiologically, and biochemically. The results obtained 15 isolates of cellulolytic bacteria that were tested for their ability to degrade cellulose. Cellulolytic test results showed that 6 isolates, namely BS1, BS7, BS10, BS11, BS14, and BS15 had a cellulolytic index of 0.8, 0.8, 0.8, 0.8, 0.8, 0.8. and 1. Isolates BS15 is the most optimal isolate in cellulose degradation with characteristics of the punctiform colony, yellow pigmentation, entire edge, convex elevation, optical opaque and smooth surface, produces catalase enzymes, is non-motile and can ferment in glucose and starch but cannot ferment lactose and also a Gram-negative


2020 ◽  
Vol 75 (9) ◽  
pp. 2554-2563 ◽  
Author(s):  
Christopher Fröhlich ◽  
Vidar Sørum ◽  
Sandra Huber ◽  
Ørjan Samuelsen ◽  
Fanny Berglund ◽  
...  

Abstract Background MBLs form a large and heterogeneous group of bacterial enzymes conferring resistance to β-lactam antibiotics, including carbapenems. A large environmental reservoir of MBLs has been identified, which can act as a source for transfer into human pathogens. Therefore, structural investigation of environmental and clinically rare MBLs can give new insights into structure–activity relationships to explore the role of catalytic and second shell residues, which are under selective pressure. Objectives To investigate the structure and activity of the environmental subclass B1 MBLs MYO-1, SHD-1 and ECV-1. Methods The respective genes of these MBLs were cloned into vectors and expressed in Escherichia coli. Purified enzymes were characterized with respect to their catalytic efficiency (kcat/Km). The enzymatic activities and MICs were determined for a panel of different β-lactams, including penicillins, cephalosporins and carbapenems. Thermostability was measured and structures were solved using X-ray crystallography (MYO-1 and ECV-1) or generated by homology modelling (SHD-1). Results Expression of the environmental MBLs in E. coli resulted in the characteristic MBL profile, not affecting aztreonam susceptibility and decreasing susceptibility to carbapenems, cephalosporins and penicillins. The purified enzymes showed variable catalytic activity in the order of <5% to ∼70% compared with the clinically widespread NDM-1. The thermostability of ECV-1 and SHD-1 was up to 8°C higher than that of MYO-1 and NDM-1. Using solved structures and molecular modelling, we identified differences in their second shell composition, possibly responsible for their relatively low hydrolytic activity. Conclusions These results show the importance of environmental species acting as reservoirs for MBL-encoding genes.


Thrombosis ◽  
2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Isis S. R. Carter ◽  
Amanda L. Vanden Hoek ◽  
Edward L. G. Pryzdial ◽  
Ross T. A. MacGillivray

Although prothrombin is one of the most widely studied enzymes in biology, the role of the thrombin A-chain has been neglected in comparison to the other domains. This paper summarizes the current data on the prothrombin catalytic domain A-chain region and the subsequent thrombin A-chain. Attention is given to biochemical characterization of naturally occurring prothrombin A-chain mutations and alanine scanning mutants in this region. While originally considered to be simply an activation remnant with little physiologic function, the thrombin A-chain is now thought to play a role as an allosteric effector in enzymatic reactions and may also be a structural scaffold to stabilize the protease domain.


2000 ◽  
Vol 28 (6) ◽  
pp. 799-803 ◽  
Author(s):  
A. Rahier ◽  
P. Benveniste ◽  
T. Husselstein ◽  
M. Taton

This report describes recent work on the process of desaturation at C5(6) of sterol precursors in plants. Biochemical characterization of the plant Δ7-sterol C5(6)-desaturase (5-DES) indicates that the enzyme system involved shows important similarities to the soluble and membrane-bound non-haem iron desaturases found in eukaryotes, including cyanide and hydrophobic chelators sensitivity, CO resistance and a requirement for exogenous reductant and molecular oxygen. Site-directed mutational analysis of highly conserved residues in 5-DES indicated that eight histidine residues from three histidine-rich motifs were essential for the catalysis, possibly by providing the ligands for a putative Fe centre. This mutational analysis also revealed the catalytic role of the functionally conserved Thr-114.


2020 ◽  
Vol 14 (1) ◽  
pp. 1-11
Author(s):  
Nicolas Hedín ◽  
Julieta Barchiesi ◽  
Diego F. Gomez-Casati ◽  
María V. Busi

Background: The debranching starch enzymes, isoamylase 1 and 2 are well-conserved enzymes present in almost all the photosynthetic organisms. These enzymes are involved in the crystallization process of starch and are key components which remove misplaced α-1,6 ramifications on the final molecule. Aim: In this work, we performed a functional and structural study of a novel isoamylase from Ostreococcus tauri. Methods: We identified conserved amino acid residues possibly involved in catalysis. We also identified a region at the N-terminal end that resembles a Carbohydrate Binding Domain (CBM), which is more related to the family CBM48, but has no spatial conservation of the residues involved in carbohydrate binding. Results: The cloning, expression and biochemical characterization of this N-terminal region confirmed that it binds to polysaccharides, showing greater capacity for binding to amylopectin rather than total starch or amylose. Conclusion: This module could be a variant of the CBM48 family or it could be classified within a new CBM family.


Author(s):  
Robert J. Nichols ◽  
Benjamin LaFrance ◽  
Naiya R. Phillips ◽  
Luke M. Oltrogge ◽  
Luis E. Valentin-Alvarado ◽  
...  

AbstractProkaryotic nanocompartments, also known as encapsulins, are a recently discovered proteinaceous organelle in prokaryotes that compartmentalize cargo enzymes. While initial studies have begun to elucidate the structure and physiological roles of encapsulins, bioinformatic evidence suggests that a great diversity of encapsulin nanocompartments remains unexplored. Here, we describe a novel encapsulin in the freshwater cyanobacterium Synechococcus elongatus PCC 7942. This nanocompartment is upregulated upon sulfate starvation and encapsulates a cysteine desulfurase enzyme via an N-terminal targeting sequence. Using cryoelectron microscopy, we have determined the structure of the nanocompartment complex to 2.2 Å resolution. Lastly, biochemical characterization of the complex demonstrated that the activity of the cysteine desulfurase is enhanced upon encapsulation. Taken together, our discovery, structural analysis, and enzymatic characterization of this prokaryotic nanocompartment provide a foundation for future studies seeking to understand the physiological role of this encapsulin in various bacteria.


1991 ◽  
Vol 54 (2) ◽  
pp. 121-123 ◽  
Author(s):  
GREGORY R. SIRAGUSA ◽  
JERRY W. NIELSEN

A microtiter plate format previously reported for the biochemical characterization of microorganisms was modified by adding agar to all of the different test media instead of using a combination of liquid and solid media. This modification, termed the Modified Microtiter Plate procedure (MMP), offered the same advantages of the original method (labor saving, inexpensive, and custom designed for special needs) as well as having the added advantages of longer term storage prior to use and ease of handling. In this study, 60 bacterial isolates (both Listeria suspects and known Listeria cultures) were biotyped using the MMP protocol and compared to results obtained using the classical tube-based US-FDA recommended protocol as the standard identification method and the BBL-Minitek system.


Planta ◽  
2011 ◽  
Vol 234 (6) ◽  
pp. 1137-1149 ◽  
Author(s):  
Amar A. Telke ◽  
Anuradha N. Kagalkar ◽  
Umesh B. Jagtap ◽  
Neetin S. Desai ◽  
Vishwas A. Bapat ◽  
...  

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