scholarly journals Pectolytic Enzyme Production By Sclerotinia Fructicola (Wint.) Rehm, and Its Role in the Pathogenesis of Stone Fruits

1964 ◽  
Vol 17 (3) ◽  
pp. 705 ◽  
Author(s):  
C Reinganum

The production of pectolytic enzymes in vivo and in vitro by S. Jructicola and by Rhizopus arrhizu8 Fischer in vivo is established.

1972 ◽  
Vol 50 (4) ◽  
pp. 767-786 ◽  
Author(s):  
R. A. A. Morrall ◽  
L. J. Duczek ◽  
J. W. Sheard

One hundred and fourteen isolates of Sclerotinia from 23 different hosts in many parts of Saskatchewan were grouped, according to their morphology, on minimal medium. Two types of seedling pathogenicity tests on six host species were conducted on at least one isolate from each morphological group and one from each host species. A total of 38 isolates was tested. Assays for pectolytic enzyme activities of the same 38 isolates were done using a defined medium, and Swede turnip and carrot tissue as substrates. Polygalacturonase, pectin transeliminase, and pectin methylesterase were all tested. The results showed that an endopolygalacturonase was probably the most prevalent enzyme. Some isolates also produced exopolygalacturonase and pectin methylesterase, but pectin transeliminase was never detected. There was no correlation between pathogenicity of the isolates and their enzyme activities in vitro or in vivo, suggesting that pectolytic enzymes are not responsible alone for pathogenicity. Agglomerative classification was used to demonstrate relationships between the isolates. However, the isolates did not fall into discrete groups based on morphological, pathological, physiological, or even combined characteristics. Neither were there clear host or geographic associations. This continuous variation rather than a segregated population is consistent with Purdy's "broader concept of the species S. sclerotiorum."


2006 ◽  
pp. 48-57
Author(s):  
R. C. Ray

The study was conducted to determine the production in vitro and in vivo of cellulases by Botrydiplodia theobromae and Rhizopus oryzae. Isolates of these organisms were obtained from the postharvest decay of sweetpotato tubers. Results revealed that B. theobrornae and R. oryzae which were isolated from postharvest spoilage of sweetpotato tubers produced endo-13-1,4-glucanase and exo-V-1 ,4-glucanase in culture and in fungi-infected tissues of sweetpotato tubers. The optimum temperature and pH for cellulose synthesis and activity were 30°C and pH 6.5, respectively.


1970 ◽  
Vol 48 (6) ◽  
pp. 1073-1077 ◽  
Author(s):  
Yu-Ho Chan ◽  
W. E. Sackston

Pectin methylesterase (PME), endopolygalacturonase (Endo-PG), exopolygalacturonase (Exo-PG), pectin trans-eliminase (PTE), polygalacturonase trans-eliminase (PGTE), cellulase, and cellobiase activities were investigated in culture filtrates of Sclerotium bataticola, and in extracts of inoculated and uninoculated sunflower stems. All of the enzymes except PTE were produced in culture filtrates of the pathogen and in diseased host tissues. Only PME was detected in healthy control plants.


1987 ◽  
Vol 26 (12) ◽  
pp. 3137-3139 ◽  
Author(s):  
Graham B. Seymour ◽  
Yvonne Lasslett ◽  
Gregory A. Tucker

1969 ◽  
Vol 47 (6) ◽  
pp. 1007-1010 ◽  
Author(s):  
L. Van Den Berg ◽  
S. M. Yang

B. cinerea and S. sclerotiorum growing in a nutrient medium on the surface of carrots at 20 °C produced significantly more extracellular pectolytic enzymes when the carrots were exposed to 94–96% relative humidity than when exposed to 98–100% relative humidity. Tests in which these organisms were grown in a nutrient solution containing pectic substances showed that they produced pectolytic enzymes in significant quantities only when readily metabolizable sources of energy (e.g. ethanol, carbohydrates) were not available. These results suggest that the low relative humidity increased enzyme production by concentrating nutrients on the carrot surface to the point where they inhibited growth of the organisms and stimulated enzyme production. Tests also showed that pectolytic enzyme activity on the surface of unwashed carrots stored 9 months at 0–1 °C was substantially higher at 90–95% relative humidity than at 98–100% relative humidity. The results indicated that reduced decay at 98–100% relative humidity was largely due to lower pectolytic enzyme production.


2020 ◽  
Vol 9 (2) ◽  
pp. 71-91
Author(s):  
Tinatin Doolotkeldieva ◽  
Saikal Bobusheva

The plant diseases caused by the Pseudomonas syringae сomplex bacteria are economically important and occur worldwide on various plants, and it is as a pathogen that has not been the object of studies and little is known about its epidemiology in Kyrgyzstan. The conventional phenotypic (LOPAT, API tests) and PCR-assisted isolation were used for the identificationof Pseudomonas syringae pv. syringaе isolates from the affected organs of local stone fruits, such as peach (Prunus persica), cherry (Prunus subgen), apricot (Prunus armeniaca), and plum (Prunus salicina) samples taken from the Chy, Issuk-Kul, and Batken regions of the country. 16S rRNA gene amplification was performed with primers 27F (5'-AGA GTT TGA TCC TGG CTC AG -3') and 907R (5 '–CCG TCA ATT CCT TTG AGT TT-3') for the identification of obtained P.syringae pv. syringaе isolates. From 40 primary isolates of Gram-negative rod-shaped bacteria, 12 were identified as Pseudomonas syringae pv. syringae, while the remaining isolates were identified as bacteria from Stenotrophomonas, Xanthomonas, Erwinia genera. The antagonist bio control agent—Streptomyces bacteria strains were screened and selected against the bacterial canker pathogen in in vitro experiments and on apricot seedlings in vivo conditions. Obtained results could encourage to develop a local bio-product based on this bioagent for spraying stone fruits with the initial manifestation of disease symptoms and to conduct preventive treatments in the fall and spring to increase the plant's resistance to pathogens.


Author(s):  
E. J. Kollar

The differentiation and maintenance of many specialized epithelial structures are dependent on the underlying connective tissue stroma and on an intact basal lamina. These requirements are especially stringent in the development and maintenance of the skin and oral mucosa. The keratinization patterns of thin or thick cornified layers as well as the appearance of specialized functional derivatives such as hair and teeth can be correlated with the specific source of stroma which supports these differentiated expressions.


Author(s):  
M.J. Murphy ◽  
R.R. Price ◽  
J.C. Sloman

The in vitro human tumor cloning assay originally described by Salmon and Hamburger has been applied recently to the investigation of differential anti-tumor drug sensitivities over a broad range of human neoplasms. A major problem in the acceptance of this technique has been the question of the relationship between the cultured cells and the original patient tumor, i.e., whether the colonies that develop derive from the neoplasm or from some other cell type within the initial cell population. A study of the ultrastructural morphology of the cultured cells vs. patient tumor has therefore been undertaken to resolve this question. Direct correlation was assured by division of a common tumor mass at surgical resection, one biopsy being fixed for TEM studies, the second being rapidly transported to the laboratory for culture.


Author(s):  
Raul I. Garcia ◽  
Evelyn A. Flynn ◽  
George Szabo

Skin pigmentation in mammals involves the interaction of epidermal melanocytes and keratinocytes in the structural and functional unit known as the Epidermal Melanin Unit. Melanocytes(M) synthesize melanin within specialized membrane-bound organelles, the melanosome or pigment granule. These are subsequently transferred by way of M dendrites to keratinocytes(K) by a mechanism still to be clearly defined. Three different, though not necessarily mutually exclusive, mechanisms of melanosome transfer have been proposed: cytophagocytosis by K of M dendrite tips containing melanosomes, direct injection of melanosomes into the K cytoplasm through a cell-to-cell pore or communicating channel formed by localized fusion of M and K cell membranes, release of melanosomes into the extracellular space(ECS) by exocytosis followed by K uptake using conventional phagocytosis. Variability in methods of transfer has been noted both in vivo and in vitro and there is evidence in support of each transfer mechanism. We Have previously studied M-K interactions in vitro using time-lapse cinemicrography and in vivo at the ultrastructural level using lanthanum tracer and freeze-fracture.


Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.


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