Composite films based on carboxy methyl cellulose and sodium alginate incorporated Thymus vulgaris purified leaves extract for food application: Assessment, antimicrobial and antioxidant properties.

The current study was conducted to develop biodegradable films with matrix composed from carboxymethyl cellulose (CMC), sodium alginate (SA) and different concentrations from Thymus vulgaris purified leaves extract (TVE). The color properties, physical properties, shape of surface, manners of crystallinity, mechanical properties and thermal properties of produced films were investigated. The continuous addition of TVE up to 1.6 % inside films matrix imparted the yellow color of extract that increased opacity to 2.98 and reduced moisture, swelling, solubility and water vapor permeability (WVP) of films up to 10.31 %, 30.17 %, 20.18 % and (1.12× 10-10 g.m-1 s-1 pa-1), respectively. Furthermore, the surface micrographs showed smoother surface after using small concentrations of TVE and turned to irregular with rough surface at higher concentrations. The FT-IR analysis indicated typically bands that demonstrated physical interaction between TVE extract and CMC/SA matrix. The fabricated films showed suitable thermal stability with decreasing trend by incorporation of TVE inside CMC/SA films. Furthermore, the developed CMC/SA/TVE2 showed significant effects on preserving the levels of moisture content, titrable acidity, force to puncture and sensory properties of cheddar cheese during cold storage days compared with commercial packaging materials.

Biochemical studies on different field strains of the pink bollworm Pectinophora gossypiella (Saund.) (Lepidoptera: Gelechiidae) in Egypt.

The specific activity of the esterases and the corresponding total proteins of the diapaused pink bollworm, Pectinophora gossypiella larvae taken from dry bolls which had been left in the cotton fields of the growing seasons of 2000&2001 were measured in four field strains representing the four Governorates: Alexandria, Al-Behaira , Kafr El-Shaikh, and Al-Gharbia. Parallel to these larvae the last generation of the pink bollworm moths trapped from Al-Behaira fields at the end of the same seasons were included in the comparative study. Besides, the susceptible strain larvae and moths from the Lab. of Bollworms Department at the Institute of Plant Protection, Cairo were used as a reference for comparing levels of resistance in the four bollworm strains representing the four Governorates and its impact on proteins and esterases types and activity. Gel scanning with respective standard molecular weights revealed variation in protein bands number and molecular weight type among the four tested field strains. Similarly, the sites of esterases on the SDS-PAGE proved high level of resistance reflected in appearance of isozymes, especially in Al-Gharbia field strain. Generally, Alexandria field strain showed the least level of resistance due to the limited area of cotton fields and the less use of insecticides in Alexandria fields. It is suggested that SDS-PAGE technique can be a biomarker for detection of susceptibility levels or resistance in the field strains, which should lead to a change in the currently applied chemicals. All field strains which had exposed annually to successive insecticide applications revealed an increase of protein bands and a decrease of esterases of lower molecular weight than those in the susceptible strain. Chemical insecticides are known to be able to act as inducers for the biosynthesis of cellular proteins or as inhibitors of enzymes; so, the molecular biochemical explanation of variations among the tested field strains can be attributed to either variation or similarity in the background exposure to the chemical control programs.

Bacterial triterpenoids of the hopane series as biomarkers for the chemotaxonomy of Burkholderia, Pseudomonas and Ralstonia spp.

Hopanoid fingerprints allowed to differentiate bacteria formerly connected to the genus Pseudomonas. Whereas all strains related to Pseudomonas and Ralstonia were devoid of any detectable hopanoid, these pentacyclic triterpenoids were found in the Burkholderia species and in related soil isolates, which contained as main hopanoid a bacteriohopanetetrol carbapseudopentose ether, accompanied by significant amounts of its novel Delta(6) unsaturated homologue. Unsaturated hopanoids represent an extremely rare feature in soil bacteria and the only known indication for a catabolism of this pentacyclic carbon skeleton in bacteria.

Advances in soil microbial ecology and the biodiversity.

Recent studies on the colony formation of soil bacteria opened the way to categorize soil bacteria into colony forming curve (CFC) groups of different growth rates. A bacterial culture collection comprising organisms from every CFC group is called an ecocollection (EC). Outlines of ECs of paddy soil 1992 and grassland soil 1987 and 1992 were described. Phylogenetic studies by 16S rDNA sequencing showed a great diversity of culture strains of the ecocollections. A set of alternative concepts was proposed; the active and the quiescent forms of bacterial cells in soil. The former is able to be cultivated and thus counted by the plate method, while the latter is not unless it transforms into the former. Based on the results several points required for extensive cataloguing of soil bacteria were noted.