Bio: Ramón Cruz-Camarillo is an academic researcher from Instituto Politécnico Nacional. The author has contributed to research in topics: Bacillus thuringiensis & Serratia marcescens. The author has an hindex of 9, co-authored 13 publications receiving 277 citations.
TL;DR: The selection and characterization of Bacillus thuringiensis strains, with ability to grow in a proteo-chitinaceous substrate (milled shrimp waste) as the sole ingredient, and the two most active proteolytic strains (Bt-103 and Bt-112) were characterized, which may show not only higher insecticidal activity, but also with the ability to produce extracellular enzymes with biotechnological applications.
Abstract: This paper reports the selection and characterization of Bacillus thuringiensis strains, with ability to grow in a proteo-chitinaceous substrate (milled shrimp waste) as the sole ingredient. Selected strains were able to produce crystal proteins, as well as proteases and chitinases as fermentation by-products. By a preliminary, qualitative screening of 152 B. thuringiensis strains, grown on media rich in protein and chitin, eight strains were selected. These strains were cultured in a liquid medium containing milled shrimp waste and their kinetics of protease production were followed. The two most active proteolytic strains (Bt-103 and Bt-112) were characterized by their crystal protein content, plasmid profiles, crystal ultrastructure, and toxicity towards Manduca sexta, Aedes aegypti and Leptinotarsa texana. The only activity recorded in these species was moderate toxicity of strain Bt-112 against Manduca sexta first instar larvae, as well as the highest proteolytic and chitinolytic activities. Its bipyramidal crystals were associated with semi-cuboidal inclusions and although its crystal proteins were similar to those of B. thuringiensis kurstaki (HD-1), its plasmid content was quite different. Serotyping of Bt-112 indicated that it belongs to serovar. tolworthi. Further studies with a similar strategy might render more strains with ability to grow in a rich waste by-product like the shrimp waste, which may show not only higher insecticidal activity, but also with the ability to produce extracellular enzymes with biotechnological applications.
TL;DR: Three selected strains of Bacillus thuringiensis native to Mexico produced endochitinases, chitobiosidases, and N-acetyl-β-glucosaminidases in a medium containing colloidal chitin as a main carbon source.
Abstract: Three selected strains of Bacillus thuringiensis native to Mexico produced endochitinases, chitobiosidases, and N-acetyl-β-glucosaminidases in a medium containing colloidal chitin as a main carbon source. Two types of chitinases were clearly identified: endochitinases and chitobiosidases. Chromosomal location of a chitinase gene in B. thuringiensis LBIT-82 was resolved.
TL;DR: This strain synthesized an endochitinase, an exochit inase and a novel N-acetylglucosaminidase, which showed two putative isoforms with isoelectric points of 5 and 8, respectively.
Abstract: Chitinolytic activity of Serratia marcescens Nima (130 U ml−1) was up to 43 times higher than those produced by other S marcescens strains This strain synthesized an endochitinase (Chi-60), an exochitinase (Chi-50) and a novel N-acetylglucosaminidase This latter showed two putative isoforms (Chi-1805 and Chi-1808) with isoelectric points of 5 and 81, respectively
TL;DR: Giant squid (Dosidicus gigas) is abundant along the Pacific Coast of Mexico and possesses a high proteolytic activity that makes it a low-quality food material as discussed by the authors.
Abstract: Giant squid (Dosidicus gigas) is abundant along the Pacific Coast of Mexico. It possesses a high proteolytic activity that makes it a low-quality food material. Squid mantle endogenous proteases were partially characterized; physicochemical and structural changes during storage at 4C were also examined. High proteolytic activity was observed at acidic and alkaline pH values. Proteases were strongly inhibited by leupeptine and pepstatin A, as well as by phenyl methyl sulfonyl fluoride, indicating the possible presence of serine, cysteine and metal proteases. Myosin heavy chain was degraded during storage, as shown on sodium dodecyl sulfate–polyacrylamide gel electrophoresis patterns, resulting in a significant decrease (P < 0.001) in muscle water-holding capacity, texture and gelling capacity. Muscle deterioration was evident in scanning electron micrographs, where the initial compact structure loosened during storage.
TL;DR: This study shows the production of chito-oligosaccharides from three different sources of colloidal chitosan and conducts a qualitative–quantitative comparison between them, using the extracellular enzyme of B. thuringiensis.
Abstract: Bacillus thuringiensis is a nonhuman pathogen bacterium that is used as a fungal and insect biocontrol agent. Because of its environmental interaction, it possesses several extracellular enzymes th...
TL;DR: Some of the chitinases produced by bacterial systems that have gained worldwide research interest for their diverse properties and potential industrial uses are reviewed.
Abstract: Chitin is among the most abundant biomass present on Earth. Chitinase plays an important role in the decomposition of chitin and potentially in the utilization of chitin as a renewable resource. During the previous decade, chitinases have received increased attention because of their wide range of applications. Chito-oligomers produced by enzymatic hydrolysis of chitin have been of interest in recent years due to their broad applications in medical, agricultural, and industrial applications, including antibacterial, antifungal, hypocholesterolemic, and antihypertensive activity, and as a food quality enhancer. Microorganisms, particularly bacteria, form one of the major sources of chitinase. In this article, we have reviewed some of the chitinases produced by bacterial systems that have gained worldwide research interest for their diverse properties and potential industrial uses.
TL;DR: This review describes traditional and novel enzymatic methods of modification of chitin and its derivatives, which may soon become competitive to conventional conversion methods.
Abstract: Chitin and its N-deacetylated derivative chitosan are two biological polymers that have found numerous applications in recent years, but their further deployment suffers from limitations in obtaining a defined structure of the polymers using traditional conversion methods. The disadvantages of the currently used industrial methods of chitosan manufacturing and the increasing demand for a broad range of novel chitosan oligosaccharides (COS) with a fully defined architecture increase interest in chitin and chitosan-modifying enzymes. Enzymes such as chitinases, chitosanases, chitin deacetylases, and recently discovered lytic polysaccharide monooxygenases had attracted considerable interest in recent years. These proteins are already useful tools toward the biotechnological transformation of chitin into chitosan and chitooligosaccharides, especially when a controlled non-degradative and well-defined process is required. This review describes traditional and novel enzymatic methods of modification of chitin and its derivatives. Recent advances in chitin processing, discovery of increasing number of new, well-characterized enzymes and development of genetic engineering methods result in rapid expansion of the field. Enzymatic modification of chitin and chitosan may soon become competitive to conventional conversion methods.
TL;DR: A simple and sensitive method based on the use of basal medium with colloidal chitin as sole carbon source supplemented with Bromo cresol purple (pH indicator dye) is proposed to evaluate large populations of Trichoderma for chit inase activity.
Abstract: Chitin is the second most abundant polymer in nature after cellulose and plays a major role in fungal cell walls. As a producer of variety of chitinase enzymes Trichoderma has become an important means of biological control of fungal diseases. A simple and sensitive method based on the use of basal medium with colloidal chitin as sole carbon source supplemented with Bromo cresol purple (pH indicator dye) is proposed to evaluate large populations of Trichoderma for chitinase activity. The soluble substrate with pH indicator dye (Bromo cresol purple, BCP) for the assay of chitinase activity on solid media is sensitive, easy, reproducible semi-quantitative enzyme diffusion plate assay and economic option to determine chitinases. Colloidal chitin derived from Rhizoctonia cell wall and commercial chitin included as a carbon source in broth also allowed selection and comparison of chitinolytic and exochitinase activity in Trichoderma spectrophotometrically. Released N-acetyl-β--D-glucosamine (NAGA) ranged from 37.67 to 174.33 mg/ml and 37.67 to 327.67 mg/ml and p-nitrophenol (pNP) ranged from 0.17 to 35.78 X 10-3 U/ml and 0.62 to 32.6 X 10-3 U/ml) respectively with Rhizoctonia cell wall and commercial chitin derived colloidal chitin supplemented broth.
••01 May 1975
TL;DR: Prodigiosin, the bright red tripyrrole pigment from Serratia marcescens, has also been identified in Pseudomonas magnesiorubra, Vibrio psychroerythrus, and two Gram-negative rod-shaped mesophilic marine bacteria not members of the genus Serratian.
Abstract: Prodigiosin, the bright red tripyrrole pigment from Serratia marcescens, has also been identified in Pseudomonas magnesiorubra, Vibrio psychroerythrus, and two Gram-negative rod-shaped mesophilic marine bacteria not members of the genus Serratia. Prodigiosin is sometimes bound to proteins; thus, extracts may require acid treatment before isolation of the pigment. Higher homologs of prodigiosin have been detected by mass spectroscopy. A mutant strain of S. marcescens produced nor-prodigiosin, in which the methoxy group of prodigiosin is replaced by a hydroxy group. Another mutant strain produced a blue tetrapyrrole pigment whose structure is a dimer of prodigiosin's rings A and B. Three novel biosynthetic analogs of prodigiosin have been obtained using a colorless mutant which does make rings A and B but not ring C and which can couple rings A and B with some added monopyrroles similar to ring C. The structures of three prodiginine (prodigiosin-like) pigments from streptomyces have been elucidated. All have the methoxytripyrrole aromatic nucleus of prodigiosin and all have an 11 carbon aliphatic side chain attached at carbon 2 of ring C. In two of the pigments the side chain is also linked to another carbon of ring C. The earlier literature about prodiginine pigments from actinomycetes has been interpreted and evaluated in light of the most recent findings. The structure elucidation of six prodiginine pigments from Actinomadurae (Nocardiae) has been completed. Only one, undecylprodiginine, is the same as from a streptomycete. For three of the six pigments, nine carbon side chains are observed and in four of them the side chain is attached to carbon 5 of ring A as well as carbon 2 of ring C so that a large ring is formed which includes the three pyrrole moieties. A section on identification summarized useful methods and presents information with which any known prodiginine pigment can be identified. The final step in the biosynthesis of prodigiosin was known to be the coupling of methoxybipyrrolecarboxaldehyde (rings A and B) with methylpentylpyrrole (ring C). Recent work using 13C-labeled precursors and Fourier transform 13C nuclear magnetic resonance has shown the pattern of incorporation for acetate, proline, glycine, serine alanine, and methionine into prodigiosin. Each pyrrole ring is constructed in a different way. Two of the streptomyces pigments have also been investigated; the pattern of incorporation is similar to that for prodigiosin. The biological activities of some prodiginine pigments are summarized. All show activity against several Gram-positive bacteria; some have anti-malarial activity. Prodigiosin has been tested clinically against coccidioidomycosis.
TL;DR: Two strains, WatG and HokM, which were identified as new strains of Pseudomonas aeruginosa and Serratia marcescens species, respectively, showed relatively high capacity and wide spectrum to degrade the hydrocarbons in gasoline, kerosene, diesel, and lubricating oil.
Abstract: Bacteria possessing high capacity to degrade gasoline, kerosene, diesel oil, and lubricating oil were screened from several areas of Hokkaido, Japan. Among isolates, two strains, WatG and HokM, which were identified as new strains of Pseudomonas aeruginosa and Serratia marcescens species, respectively, showed relatively high capacity and wide spectrum to degrade the hydrocarbons in gasoline, kerosene, diesel, and lubricating oil. About 90–95% of excess amount of total diesel oil and kerosene added to mineral salts media as a sole carbon source could be degraded by WatG within 2 and 3 weeks, respectively. The same amount of lubricating oil was 60% degraded within 2 weeks. Strain HokM was more capable than WatG in degrading aromatic compounds in gasoline. This strain could also degrade kerosene, diesel, and lubricating oil with a capacity of 50–60%. Thus, these two isolates have potential to be useful for bioremediation of sites highly contaminated with petroleum hydrocarbons.