Background. Rosemary (Rosmarinus offi cinalis L.) is a spice and medicinal herb widely used around the world of the natural antioxidants, and it has been widely accepted as one of the spices with the highest antioxidant activity. Transglutaminase (EC 2.3.2.13; TGase) is an enzyme capable of catalysing acyl transfer reactions by introducing covalent cross-links between proteins, as well as peptides and various primary amines. TGase activity in plants was fi rst observed in pea seedlings, and subsequently found in organs of both lower and higher plants. Recently, TGase has captured researchers' interest due to its attractive potential application in food industries. Therefore, the objectives of this study are isolation and purifi cation of TGase from new plant source rosemary (Rosmarinus offi cinalis L.) leaves at the laboratory scale. Moreover, investigation of the biochemical properties of the purifi ed TGase to provide a suitable TGase enzyme for food industry applications are in focus. Material and methods. Rosemary (Rosmarinus offi cinalis L.) leaves was used as a new plant source to TGase. The biochemical characteristics of the crude and purifi ed enzyme were determined. Results. Rosemary (Rosmarinus offi cinalis L.) TGase was purifi ed to homogeneity by successive three purifi cation steps including ammonium sulfate precipitatation, ion exchange chromatography on DEAE-Sephadex A-50 column and Size exclusion column chromatography on Sephadex G-100 column. Under experimental conditions, 20-30% of ammonium sulfate saturation in the enzyme solution had a high yield of enzyme activity could be obtained. The purifi ed enzyme from the Sephadex G-100 column had 21.35% yield with increased about 7.31 in purifi cation fold. Rosemary TGase exhibited optimum activity at pH 7.0 and 55°C for the catalytic reaction of hydroxylamine and Z-Gln-Gly. The purifi ed TGase almost maintained full activity after incubation for 15 min up to 60°C and it was completely inactivated at 85°C. The rosemary TGase was stimulated at 2-6 mM CaCl 2 concentrations while it lost about 5-20% from its activity by increasing CaCl 2 concentration. Sodium chloride (2-14%) shows no noticeable inhibition of the purifi ed TGase activity. Mg +2 , Ba +2 were acivited by the purifi ed TGase while it was strongly inhibited by Fe +2 , moderately by Cu +2 and Mn +2 . Conclusion. This paper reports on the purifi cation and characterisation of TGase from newly isolated plant, rosemary (Rosmarinus offi cinalis L.) leaves. Finding results of the TGase properties make this enzyme a good candidate for application in the food industry. However, additional work is required to increase activity yield during extraction and purifi cation for commercial scale of TGase from this plant.
SUMMARYThe viruses causing two tomato leaf‐curl diseases, tomato leaf curl without vein thickening (TLCV) and tomato leaf curl with vein thickening (TVTV), were both transmissible (to tomato and other hosts) by the aleurodid Bemisia tabaci (=B. gossypiperda M. & L.) and by grafting, but not by mechanical inoculation of expressed sap. A third virus, which arrested growth of the shoot apices and caused a disease referred to as tomato condensed top (CT), was transmissible only by grafting and was not studied in detail.Both TLCV and TVTV belong to the complex of tobacco leaf‐curl viruses described by other workers, but the different effects of the two and their failure to interfere with one another in plants suggest that they are not strains of one virus.TLCV and TVTV were not transmissible to cotton nor was cotton leafcurl virus transmissible to tobacco, tomato or Datura stramonium L. Virus transmitted from okra with leaf curl caused leaf curl both in cotton and tobacco, suggesting that the okra was infected with a mixture of viruses or with a virus having a new combination of properties. TVTV was transmitted with difficulty to okra, causing vein thickening.
SUMMARY : Ultraviolet irradiation of spores of three leaf-infecting fungi, Botrytis fabae, Uromyces fabae (causes of 'chocolate spot' and rust of broad beans, respectively) and Erysiphe graminis (cause of barley powdery mildew), decreased their pathogenicity, as assessed by counts of local lesions or pustules. The infectivity of B. fabae was lost more rapidly than the ability to form colonies on agar; with E . graminis infectivity was lost more rapidly than the ability to germinate. Ultraviolet radiation damage to spores of all three fungi was mitigated by exposure to daylight after irradiation. The extent of such photoreactivation of B. fabae was the same whether the spores were on the host plant or in vitro. Ultraviolet irradiation of leaves before inoculation decreased the number of pustules of E. graminis on barley, had no effect on the pustule number caused by U . fabae and increased the number of lesions caused by B. fabae on broad beans. Rubbing leaves with Celite before inoculation also increased the number of B. fabae lesions. Retaining u.v.-irradiated broad bean plants in daylight or darkness after inoculation with unirradiated spores of B. fabae did not significantly alter the lesion number. In contrast, more pustules of E . graminis developed on u.v.-irradiated barley leaves kept in daylight than in darkness.Ultraviolet (u.v.) radiation can affect micro-organisms in many ways, and some of the consequences can be mitigated by exposure to visible light afterwards, Kelner (1949) found that u.v.-irradiated bacteria and spores of fungi that would not grow when left in darkness, grew when illuminated.
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