Role Of Cellulase Research Articles

An In Vitro Study on the Role of Cellulases and Xylanases of Bacillus subtilis in Dairy Cattle Nutrition.

The administration of Bacilli to dairy cows exerts beneficial effects on dry matter intake, lactation performance, and milk composition, but the rationale behind their efficacy is still poorly understood. In this work, we sought to establish whether cellulases and xylanases, among the enzymes secreted by B. subtilis, are involved in the positive effect exerted by Bacilli on ruminal performance. We took advantage of two isogenic B. subtilis strains, only differing in the secretion levels of those two enzymes. A multi-factorial study was conducted in which eight feed ingredients were treated in vitro, using ruminal fluid from cannulated cows, with cultures of the two strains conveniently grown in a growth medium based on inexpensive waste. Feed degradability and gas production were assessed. Fiber degradability was 10% higher (p < 0.001) in feeds treated with the enzyme-overexpressing strain than in the untreated control, while the non-overexpressing strain provided a 5% increase. The benefit of the fibrolytic enzymes was maximal for maize silage, the most recalcitrant feed. Gas production also correlated with the amount of enzymes applied (p < 0.05). Our results revealed that B. subtilis cellulases and xylanases effectively contribute to improving forage quality, justifying the use of Bacilli as direct-fed microbials to increase animal productivity.

OPTIMIZATION OF THE PROCESS OF SACCHARIFICATION OF HARDWOOD CELLULOSE UNDER THE ACTION OF HYDROLASES AND OXYGENASES

A complex of enzymes has been selected for the exhaustive enzymatic conversion of semi-bleached sulfate hardwood pulp to monosaccharides, carried out in the substrate concentration range from 100 to 300 g/l. The role of cellulases, xylanase, β-glucosidase and polysaccharide monooxygenase in the intensification of the process is shown.

Cellulase (Endo β-1,4 Glucanase) and Cell Wall Breakdown during Anther Development in the Sweet Pea ( Lathyrus odoratus L.): Isolation and Characterization of Partial cDNA Clones

The possible role of cellulase in cell wall breakdown during maturation of the anthers of Lathyrus odoratus L. was studied. Cellulase (β-1,4 glucanase) increased 150-fold from the premeiotic stage, reaching peak levels during the degradation of the primary walls around the tetrads and the tapetum. The enzyme activity declines as the pollen mature and anthers yellow but there is still large amounts of activity at the time of dehiscence. Four partial cDNA clones, which have a high degree of sequence identity with other plant cellulases, have been isolated by PCR from anther cDNA. Northern analysis showed that these clones differ dramatically in their mode of temporal expression.

The role of cellulase in hormonal regulation of shoot morphogenesis in tobacco callus

A polyclonal antibody raised against cellulase (EC 3.2.1.4.) from callus ofNicotiana tabacum L. cv. Petit Havana SR1 reduced cellulase activity and induced shoot formation in tobacco callus in the presence of callus maintaining concentrations of auxin and cytokinin. Shoot induction as well as reduction of the cellulase activity was also obtained by withdrawing auxin from the callus medium. The effect of the two hormones on cellulase activity in the tobacco tissue was examined by varying the concentration of one of the hormones α-naphthylacetic acid (NAA) or benzylaminopurine (BAP) at a time while the other was kept at a level sufficient for either callus growth or shoot induction. While NAA stimulated the enzyme activity increasingly with concentration in the range 5 × 10−7 M to 5 × 10−5 M at both levels of BAP, BAP only stimulated the cellulase activity at an optimum concentration of 5 × 10−6 M when NAA was present at a level sufficient to induce callus growth. The results point to a pivotal role of the downward regulation of cellulase in the initiation of shoot induction. A series of events leading to oriented cell divisions as a result of the lowered cellulase level during the initial phase of the morphogenetic process is discussed.

The Role of Cellulase (Endo‐1,4‐β‐Glucanase) in Gummosis Diseases in Apricot

AbstractApricot gummosis pathogens — the fungi Hendersonula toruloidea, a Cytosporina sp. and a Cytospora sp., produce cellulase (endo‐1,4‐β‐glucanase, carboxymethylcellulase, CMCase) in culture. Cytospora sp. produced significantly lower amounts of cellulase than H. toruloidea and Cytosporina sp. The tendency of cellulase accumulation inside apricot stems infected with either H. toruloidea or Cytosporina sp. is similar: most of the cellulase was found in the necrotic area, whereas comparatively small amounts accumulated at the advancing edge of the disease symptom. H. toruloidea produces cellulase with a molecular mass of 76 kDa.

Structure and regulation of the Erwinia carotovora subspecies carotovora SCC3193 cellulase gene celV1 and the role of cellulase in phytopathogenicity.

The celV1 gene encoding a secreted cellulase (CelV1) of Erwinia carotovora subsp. carotovora SCC3193 was cloned and its nucleotide sequence determined. The gene contains an open reading frame of 1511 bp and codes for an exported protein of 504 amino acids. The predicted amino acid sequence of CelV1 was highly similar to that of CelV of another E. c. subsp. carotovora strain SCR1193 but completely different from the previously characterized cellulase, CelS, of the strain SCC3193. Gene fusions to the lacZ reporter were employed to characterize the regulation of celV1 and celS. Both genes are coordinately induced in a growth phase-dependent manner and are catabolite repressed. Expression of celV1 but not celS was stimulated by plant extracts. The celS gene was expressed at a much lower level than celV1 under all conditions tested. Inactivation of the celV1 gene in E. c. subsp. carotovora strain SCC3193 by marker exchange showed that celV1 encodes the major cellulase of strain SCC3193, as the resulting mutant strain SCC6001 was devoid of cellulase activity. CelV1 mutants exhibited reduced virulence suggesting that CelV1, although not absolutely required for pathogenicity, enhances the ability of strain SCC3193 to macerate plant tissue. Inactivation of the celS gene in the celV1 mutant did not lead to any further decrease in virulence.

The role of cellulase in hormonal regulation of shoot morphogenesis in tobacco callus

The role of cellulase in hormonal regulation of shoot morphogenesis in tobacco callus

The role of cellulases in the mechanism of changes of cell walls of Funaria hygrometrica moss protonema at clinostating.

Using electroncytochemical and biochemical methods, differences between the cytochemical reaction intensity and activity of the cellulosolytic enzymes in Funaria hygrometrica moss cells grown for 30 days in the horizontal clinostat (2 rev/min) and in control have been studied. It has been shown that on clinostating the precipitate amount and size increases with the cellulase activity enhancement in the periplasmic space and protonema cell walls, when compared to control. Using biochemical methods it has been found that the activity of both endo-1,4-beta-glucanase and exo-1,4-beta-glucanase was higher under these conditions. A decrease of cellulose total content, its crystalline form, and pectic substances as well as an increase of hemicellulose content have been revealed in the clinostated material compared to control. Data obtained are discussed regarding the possible mechanism of cellulase activation and synthesis inhibition and cellulose crystallization in plant cell walls at clinostating.

The purification of an anther cellulase (β(1:4)4-glucan hydrolase) from Lathyrus odoratus L. and its relationship to the similar enzyme found in abscission zones

A cellulase (β(1:4)4-glucan hydrolase) has been purified 700-fold by cellulose affinity chromatography from anthers of Lathyrus odoratus L. Two forms are present. The major species has a molecular weight of 49 kDa and a p I value of 8.0; the minor a molecular weight of 51 kDa and a p I value of 7.8. Both proteins are recognized by antibodies raised against the ethylene/IAA regulated bean ( Phaseolus vulgaris L.) abscission zone cellulase which has a more basic p I value and some unique antigenic determinants. Ethylene induced Lathyrus flower bud abscission zones contain two forms of cellulase apparently identical to those in the anthers. The possible role of cellulase in the development of anthers is discussed.

Production of xylanolytic enzymes in association with the cellulolytic activities of Penicillium funiculosum

Penicillium funiculosum produced 16 and 0.4 units ml −1 of d-xylanase (1,4-β- d-xylan xylanohydrolase, EC 3.2.1.8) and β- d-xylosidase (1,4-β- d-xylan xylohydrolase, EC 3.2.1.37), respectively, in shake flasks. Both enzymes were 100% stable when heated at 50°C for 30 min and on prolonged heating d-xylanase and β- d-xylosidase showed 46 and 20% loss, respectively. Maximum hydrolysis (75%) of d-xylan was obtained when the end products were removed. The addition of β- d-xylosidase markedly influenced the degree of hydrolysis of d-xylan. End-product analysis of the d-xylan hydrolysate showed the presence of d-xylose, d-xylobiose, d-xylotriose, d-xylotetraose, d-xylopentose and l-arabinose. The fractionation of culture filtrate of Penicillium funiculosum grown on cellulose powder or in a combination of cellulose powder and wheat bran indicated the presence of two d-xylanases. The role of cellulase [see 1,4-(1,3;1,4)-β- d-glucan 4-glucanohydrolase, EC 3.2.1.4] and d-xylanase on the overall hydrolysis of pure cellulose and lignocellulosic substrates is discussed.

The Role of Cellulase in Hyalocyst Pore Formation in the Moss Syrrhopodon texanus

The Role of Cellulase in Hyalocyst Pore Formation in the Moss Syrrhopodon texanus

Ultrastructural Changes in the Walls of Ripening Avocados: Transmission, Scanning, and Freeze Fracture Microscopy

Avocado fruit at several documented stages of ripening was prepared for transmission, scanning, and freeze fracture electron microscopy. Changes in the ultrastructural organization of the cell wall were studied by each technique and correlated with changes in the activity of wall-hydrolytic enzymes. Initial wall breakdown apparently involves degradation of pectins in the matrix and in the middle lamella, corresponding to the reported increase in polygalacturonase activity in the tissue. In later stages of ripening, there is a loss of the organization and density of the wall striations accompanied by an increase in fruit softening. The role of cellulase, which becomes highly active during ripening of avocados and several other fruits, is still somewhat questionable. However, both thin sections and freeze fracture replicas of ripening avocados indicate a loss of fibrillar components of the wall during ripening and, therefore, indicate a possible role for cellulase in fruit softening. No correlation between ...

Role of Cellulase in Aerenchyma Development in Sunflower

A hypothesis that ethylene causes aerenchyma development in waterlogged plants through increased cellulase activity was tested with sunflower, Helianthus annuus L. Treatment with commercial cellulase induced aerenchyma development in sunflower stem sections. Some of the cellulase-treated cortical cells enlarged radially and some disintegrated, leading to intercellular space. Cell disintegration started with progressive plasmolysis and severe plasmolysis was associated with or was apparently followed by cell wall breakdown. Localized stem treatment of an intact sunflower with ethylene increased cellulase activity in that part of the stem. Localized stem treatment of an intact sunflower with a water jacket increased cellulase activity in that part of the stem. When the lower part of the sunflower was waterlogged, the cellulase activity in the waterlogged stem increased. Present and earlier results suggest that aerenchyma development is a plant adaptation to waterlogging conditions. The deficiency of oxygen in a waterlogged plant triggers the anaerobic stimulation of ethylene production, which causes an increase in cellulase activity leading to aerenchyma development and enhancing the transport of oxygen to the roots. It is proposed that there is competition between neighboring cortical cells for water after an increase in cell wall plasticity by the action of cellulase. The competition causes progressive plasmolysis and eventual disintegration of weaker cells.

Reducing preharvest drop of ‘Temple’ orange fruits by 2,4-D — Role of cellulase in the calyx abscission zone

One or two treatments of 2,4-D (18 p.p.m.) applied to ‘Temple’ orange trees during the last 6 weeks before the regular picking-period in late January, successfully reduced natural preharvest fruit abscission, allowing picking to be delayed by at least one month, and thus producing better external and internal fruit quality. It has been demonstrated for the first time that the delaying effect of auxin treatment on preharvest abscission was directly related to the decrease in the activity of endo- and exo-cellular cellulase. Most of the increase in cellulase activity during the abscission process was, however, due mainly to the activity of exo-cellular cellulase. When frost occurred a few days after application of 2,4-D, the auxin treatment significantly decreased total cellulase activity, thus reducing fruit abscission. The data proved that, except for the difference in the length of time between application and the onset of the hormone effect, the control mechanism of 2,4-D on abscission and on cellulase activity in intact fruit is similar to that previously reported for fruit explants.

The digestion of cellulose and other dietary components, and pH of the gut in the amphipod Gammarus pulex (L.)

SUMMARY. Gut extracts from Gammarus pulex hydrolysed native and other cellulose substrates in vitro. Digestive fluid cellulase is probably endogenous as cell‐free fluid mediated cellulose hydrolysis, but no bacteria were isolated from the fluid which produced a detectable extra‐cellular cellulase. There was no apparent digestion of plant cell walls during their passage along the digestive tract, which took about 5–7 h at 10°C. The pH sensitivities of the digestive enzymes and the pH of the various regions of the gut suggest that carbohydrate digestion occurs in the proventriculus, midgut glands and anterior midgut, but protein digestion may be largely limited to the posterior midgut. The pH of the digestive fluid was altered slightly, but significantly, by the consumption of different natural and artificial test diets and by starvation. The most probable reason for the non‐digestion of plant cell‐walls is the lack of necessary enzymes other than cellulase. The role of cellulase may be confined to digesting the many small, non‐cellular particles which are present in the gut.

The Role of Cellulase and Polygalacturonase in Abscission of Young and Mature Shamouti Orange Fruits

AbstractDuring the first eight weeks after setting young citrus fruits gradually lose their ability to abscise at the abscission zone between the stem and the pedicel; in fruits older than eight weeks abscission occurs at the calyx area. The activity of cellulase and polygalacturonase in the two abscission zones was markedly increased before and during abscission, and was localized mainly in the abscission zone. Ethylene accelerated the increase in enzymic activity after an 8‐ to 10‐h lag period; 2,4‐D delayed abscission and enzymic activity when applied during the first 24 h after excision. During this period 2,4‐D also partly suppressed the enhancing effect of ethylene. Early application of cyclo‐heximide inhibited the formation of the enzymes and thus abscission was delayed to a certain extent.Although there are some indications that the relationship between enzymic activity and abscission is a complex one, the data presented indicate that cellulase and polygalacturonase play a significant role in abscission of citrus fruits at various developmental stages. Both enzymes act almost simultaneously and are equally controlled by ethylene and 2,4‐D.

Role of Cellulase in Abscission of Citrus Fruits1

Abstract The concept of cellulolytic enzymes being involved in abscission has been confirmed and extended in this study to include the fruits of ‘Calamondin’ (Citrus madurensis Lour.) and ‘Valencia’ sweet orange [C. sinensis (L.) Osbeck]. Data have been presented which demonstrate that an increase in cellulase activity is associated with natural and chemically accelerated abscission of citrus fruits. Ethylene, the most effective accelerant of abscission studied, shortened the time for attainment of measurable increases in cellulase activity preceding separation and shortened the time between detectable increases in cellulase activity and attainment of high cellulase activity. Pectinase did not seem to be a major factor associated with abscission of ‘Calamondin’ and ‘Valencia’ fruit. The effect of inhibitors of protein and RNA synthesis on abscission of ‘Calamondin’ and ‘Valencia’ fruit was determined and cycloheximide was found to inhibit both abscission and increased cellulase activity. Cellulase-containing proteins extracted from tissues immediately surrounding and including abscission zones were separated electrophoretically and the appearance of a new protein band with carboxymethyl-cellulase activity was noted in this tissue during abscission.

Abscission: Role of Cellulase

Cellulase (beta-1,4-glucan-glucanohydrolase EC 3.2.1.4) activity increased during abscission and was localized in the cell separation layer of Phaseolus vulgaris L. cv. Red Kidney (bean), Gossypium hirsutum L. cv. Acala 4-42 (Cotton) and Coleus blumei Benth. Princeton strain (Coleus) abscission zone explants. Cellulase activity was optimum at pH 7, was reduced by one-half after heating to 55 degrees for 10 min, and was associated with the soluble components of the cell. Explants treated with aging retardants (indoleacetic acid, (6)N-benzyladenine, and coumarin), CO(2), actinomycin D or cycloheximide had less cellulase activity than untreated controls. Ethylene increased cellulase activity of aged explants after a 3-hr lag period but had no effect on cellulase activity of freshly excised explants. It was concluded that 1 of the roles of ethylene in abscission is to regulate the production of cellulase which in turn is required for cell separation.