A total of 54 broiler flocks during the first two weeks of life was used to investigate the incidence of avian pathogenic E. coli in Egypt; 28 isolates (51.85%) were revealed by colony morphology and ...biochemical identification which then investigated for their serogroups and only 18/28 isolates were serotyped. The most prevalent serotypes were O115, O142, O158, O55, O125, O114, O27, O20, and O15. By application of polymerase chain reaction (PCR), 83.3% (15/18) of the serotyped isolates were confirmed to be
, and 93.3% (14/15), 46.6% (7/15), and 20% (3/15) of isolates harbored the
,
and
genes, respectively. Virulence testing of the selected 13 APEC isolates on the specific-pathogen-free (SPF) chicks revealed them to be highly virulent (15.4%), moderately virulent (23.1%), and avirulent (61.5%); however, all isolates (100%) were extremely virulent towards SPF embryonated chicken eggs. Antibiotic resistance (100% of isolates (n = 13)) was observed for ampicillin, amoxycillin-clavulanic acid, and tetracyclines, colistin (92.31%; 12/13), doxycycline and spiramycin (84.62%; 11/13), florfenicol (69.23%; 9/13), cefotaxime (61.54%; 8/13), and ciprofloxacin (53.85%; 7/13). The highest percentage of sensitivity (53.85% of isolates; 7/13) was recorded for ofloxacin and enrofloxacin followed by gentamycin (46.15%; 6/13). The results suggest that the diagnosis of
with PCR is rapid and more accurate than traditional methods for
identification; moreover, the presence or absence of
and/or
genes is not an indicator of in vivo pathogenicity of
. Thus, further studies, including a wider range of virulence genes and gene sequencing, are required. In addition, serotyping has no effect on the virulence of
.
Abstract Random Amplified Polymorphic DNA (RAPD) markers were used to investigate genetic diversity and phylogenetic relationships among 10 species belonging to the genus Amaranthus L. The results ...showed that the polymorphism in cultivated species was lower than that in wild ones, reflecting the selection pressures of domestication on genetic diversity in cultivated species. A specific RAPD marker was detected for each of A. powellii PI 572262, A. tricolor PI 462129, A. palmeri PI 607455, A. caudatus PI 511679 and A. quitensis PI 511744. The overall mean similarity index of amplified fragments generated by RAPD primers on genomic DNA of Amaranthus accessions indicated that A. hypochondriacus was the closest grain amaranth to A. hybridus, followed by A. caudatus and A. cruentus. A. tricolor had a maximum genetic distance from grain amaranth species, confirming its morphological classification in a distinct subgenus Albersia. Similarly, the accessions of A. palmeri were separated in a distinct cluster, supporting its classification in a distinct subgenus Acnida. A. hybridus accessions were gathered together with grain amaranth species, thereby supporting the single progenitor hypothesis for grain amaranths. A. spinosus was separated on a distinct principal coordinate axe, indicating its low correlation with other species and confirming its morphological classification in a distinct section, i.e. Centrusa.
Eighteen L. inconspicuous accessions collected from different countries were evaluated for variations of seed weight, seed protein content, and electrophoretic patterns of the total seed proteins ...analyzed under reducing conditions. They exhibited a reasonable genetic variability for the evaluated traits. This genetic variability revealed that improvement through simple selection for these traits is possible. The variation between the seed size of this accessions was attributed to the development process or the life cycle of the plant, and the environmental condition to which the mother plant is exposed. On the other hand, the variation in protein content among the different accessions may be due to genotype and/or seasonal influences. The relationship between protein content and 100 seeds weight in the evaluated accessions was reversible, the accession showed the lowest quantity of the total seed proteins was the accession that exhibited highest weight of 100 seeds and nearly vice versa. Each accession gave a different electrophoretic pattern except the two accessions collected from Iran, exhibited an identical one. The difference in 100 seed weight and total protein content of these accessions indicated that they are not genetically identical. The variation in the electrophoregram of the evaluated accessions located in the bands with molecular weight more than 98 kDa, the heavy subunits of alpha-lathyrin subunits and the region molecular weight around 70 kDa. The results of cluster analysis based of SDS/PAGE under reduction conditions indicated that genetic diversity between Turkish, Syrian, and Iranian and Australian accessions is pronounced, and Turkish accessions are closer to both Syrian and Iranian accessions than the relation between Syrian and Iranian. This suggested that crosses between the Iranian and Syrian accessions could create more genetic variability than crosses with Turkish accessions. The distribution of Turkish and Syrian accessions between more than one clusters revealed that genetic diversity and geographic distribution were independent of each other. PCA showed that all accessions were separated on the first principal component, indicating that the accessions showed a good association, due, probably, to parallel evolution.
The genes encoding the glycinin subunits G2 and G4 were molecularly manipulated and modified to test the possibility of increasing the nutritional value of soybean seed proteins. The recombinant DNAs ...pSP65/G2HG4, PSP65/G4HG2, pSP65/248 Metl, pSP65/248 Met2,3 and pSP65/248 Metl.2,3 were used in in vitro translation to produce (i) chimeric proteins consisting of reciprocally exchanged acidic and basic G2 and G4 domains and (ii) Gy4 point mutants with an increased number of methionine residues. The ability of the recombinant proteins to assemble into proper quaternary structures was investigated using sucrose gradient fractionation. The data produced by this study could provide valuable clues for the potential improvement of genetically modified crops.
Electrophoretic analysis of germinating linseed proteins showed a gradual decrease in the quantity of a protein with a molecular weight of 42 kDa. This protein accumulates after 36 h of germination ...in synchronisation with an increase in lipase activity, and a decrease in the quantity of the total lipids. The 42 kDa subunit was found to be a lipid body membrane protein. This protein was isolated and identified by immunoprecipitation as a subunit of lipase. The linseed lipase acted on a wide range of triacylglycerols and had optimal activity at pH 4.7. The activity of the enzyme was slightly affected by a high concentration of salts and EDTA, while high concentrations of non-ionic detergents exhibited a pronounced inhibitory effect. These data suggest that the isolated 42 kDa protein is most likely a linseed acid lipase responsible for the breakdown of lipids during germination.
Buffer and water extracted proteins were quantitatively measured by Bradford method (1976) for 18 taxa of five species of genus Lotus. The somatic chromosome number, chromosome length, and chromosome ...arm ratio were determined. The effect of supernumerary chromosome on protein percentage and an interpretation for the variation in protein quantities between the different taxa of each species were discussed.
Whitefly (
)-transmitted Geminiviruses cause serious diseases of crop plants in tropical and sub-tropical regions. Plants, animals, and their microbial symbionts have evolved complex ways to interact ...with each other that impact their life cycles. Blocking virus transmission by altering the biology of vector species, such as the whitefly, can be a potential approach to manage these devastating diseases. Virus transmission by insect vectors to plant hosts often involves bacterial endosymbionts. Molecular chaperonins of bacterial endosymbionts bind with virus particles and have a key role in the transmission of Geminiviruses. Hence, devising new approaches to obstruct virus transmission by manipulating bacterial endosymbionts before infection opens new avenues for viral disease control. The exploitation of bacterial endosymbiont within the insect vector would disrupt interactions among viruses, insects, and their bacterial endosymbionts. The study of this cooperating web could potentially decrease virus transmission and possibly represent an effective solution to control viral diseases in crop plants.
The major storage protein of jackbean (Canavalia ensiformis) has been purified by a protocol involving ammonium-sulphate precipitation, gel filtration and ion-exchange chromatography. The protein was ...shown by partial amino-acid-sequence data to be homologous to vicilin, a major storage protein of pea (Pisum sativum), and is thus a member of the family of legume 7S proteins exemplified by pea vicilin. This protein is thus referred to as jack-bean vicilin rather than "canavalin" or "precanavalin" as previously used. Other properties of the jack-bean vicilin (e.g. subunit relative molecular mass (Mr) and structure, resistance to proteolysis) show similarity to phaseolin, the major 7S storage protein of Phaseolus vulgaris. Jack-bean vicilin contained no detectable α-mannosidase activity, either as isolated from mature or germinating seeds, or after proteolytic treatment. α-Mannosidase was also purified from jack beans, and was shown to have a subunit Mr of approx. 120,000; it was separated completely from jack-bean vicilin by a similar protocol to that used for purifying the latter. The α-mannosidase was proteolytically cleaved after seed germination, but did not give polypeptides of the same Mr as jack-bean vicilin. It was concluded that α-mannosidase and jack-bean vicilin are not related proteins.
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