There is a growing demand to find an effective extraction process of sulfated polysaccharides from brown algae to conserve its structure and biological activity. Fucoidan was recovered from Sargassum sp. using a hot buffer extraction process. BoxeBenhken experimental design was evaluated to study different conditions of temperature, pH and buffer: alga ratio on fucoidan yield and its sulfate content. By solving the regression equations and analyzing 3-D plots, the optimum conditions were at extraction temperature 60
C, pH 4.0, and ratio of buffer: alga 10.0 mL/g. Under these conditions, the experimental fucoidan yield, and sulfate content were 19 and 47.6% (w/w), respectively, which were in good agreement with the predicted values. The use of hot buffer extraction was efficient to obtain a high fucoidan yield with maintaining high sulfate contents. Fucoidan preparations showed variations in antioxidant properties using various antioxidant assays. Increasing reducing antioxidant activity and hydroxyl radical scavenging of fucoidan extracts was attributed to increasing total sugars, fucose, and uronic acids. The data obtained suggested that the sulfate groups might act as reductones rather than radical scavengers to contribute to the antioxidant activity of fucoidan. Additionally, proteinaceous and phenolic compounds co-extracted with crude fucoidan contributed to its antioxidant potential. Crude fucoidan demonstrated good emulsion stabilizing capacities, especially with cedar wood oil and xylene. These results suggest the use of the crude fucoidan as a good alternative to many synthetic polymers, as well as other natural polysaccharides, in several applications in the food, pharmaceutical, cosmetic, textile, paper and petroleum industries.

There is a growing demand to find an effective extraction process of sulfated polysaccharides from brown algae to conserve its structure and biological activity. Fucoidan was recovered from Sargassum sp. using a hot buffer extraction process. BoxeBenhken experimental design was evaluated to study different conditions of temperature, pH and buffer: alga ratio on fucoidan yield and its sulfate content. By solving the regression equations and analyzing 3-D plots, the optimum conditions were at extraction temperature 60
C, pH 4.0, and ratio of buffer: alga 10.0 mL/g. Under these conditions, the experimental fucoidan yield, and sulfate content were 19 and 47.6% (w/w), respectively, which were in good agreement with the predicted values. The use of hot buffer extraction was efficient to obtain a high fucoidan yield with maintaining high sulfate contents. Fucoidan preparations showed variations in antioxidant properties using various antioxidant assays. Increasing reducing antioxidant activity and hydroxyl radical scavenging of fucoidan extracts was attributed to increasing total sugars, fucose, and uronic acids. The data obtained suggested that the sulfate groups might act as reductones rather than radical scavengers to contribute to the antioxidant activity of fucoidan. Additionally, proteinaceous and phenolic compounds co-extracted with crude fucoidan contributed to its antioxidant potential. Crude fucoidan demonstrated good emulsion stabilizing capacities, especially with cedar wood oil and xylene. These results suggest the use of the crude fucoidan as a good alternative to many synthetic polymers, as well as other natural polysaccharides, in several applications in the food, pharmaceutical, cosmetic, textile, paper and petroleum industries.

This study represents an analysis of the thermal aggregation of human serum albumin (HSA) induced by novel rosin modified compounds. The aggregation process causes conformational alterations in the secondary and tertiary structures of the proteins. The conversion of globular protein to amorphous aggregates was carried out by spectroscopic, calorimetric and microscopic techniques to investigate the factors that are responsible for the structural, conformational and morphological alteration in the protein. Our outcome results show that the aggregation of HSA was dependent on the hydrophobicity, charge and temperature, because the formation of amorphous aggregates occurs in the presence of a novel cationic rosin compound, quaternary amine of rosin diethylaminoethyl ester (QRMAE), at 40°C and pH 7.4 (at 25°C on similar pH value, there was no evidence of aggregate formation). In addition, the parent compound of QRMAE i.e.; abietic acid, and other derivatives such as nonionic rosin compounds [(RMPEG-750) and (RMA-MPEG-750)] do not shows the aggregating property. This work provides precise and necessary information that aid in the understanding the effects of rosin derivative compounds on HSA. This study also restrains important information for athletes, health providers, pharmaceutical companies, industries, and soft drink-processing companies.

Microbial lipase today occupies a place of prominence among biocatalysts owing to their ability to catalyze a wide variety of reactions in aqueous and non aqueous media. In this study, Aspergillus terreus showed high lipase production in submerged culture (15.463 ± 0.39 U/mg). The optimum conditions for lipase production by A. terreus were pH range 7-9, a temperature of 30-45ºC for a period of 6 days and ionic strength 60 mM NaCl. Lipase production was also detected when A. terreus was grown on different hydrocarbons, olive oil or tween 80 but not on sugars indicating that the enzyme is inducible by hydrocarbons as well as oils. The kinetics studies showed that the Km value for A. terreus was 8.12 μmol, the optimum pH for lipase activity was 6, the optimum temperature was 30 ± 1ºC and lipase activity could tolerate high levels of ionic strength; however the fungal growth and lipase productivity were very sensitive to increase ionic strength.

Introduction No one can deny the importance of taxonomy in the field of science. One of its major goals is to identify species that inhabit a certain habitat. Zooplankton refers to the weak swimming animals or those which move under the mercy of water current. They occupy a central position in the food chain in the aquatic ecosystems between primary producers and higher consumers. Zooplankton plays an important role in a lake’s ecosystem and food chain. Unlike algae, or phytoplankton, zooplanktons are microscopic animals that do not produce their own food. They are responsible for eating millions of little algae that may otherwise grow to an out-of control state. Through their consumption and processing of phytoplankton and other food sources, zooplankton plays a role in aquatic food webs, as a resource for consumers on higher trophic levels (including fish), and as a conduit for packaging the organic material in the biological pump. Since they are typically small, zooplankton can respond rapidly to increases in phytoplankton abundance for instance, during the spring bloom. The present book is an attempt to identify the common species of zooplankton inhabiting north-west region of Saudi Arabia (Tabuk). The species recorded in the book were collected by the authors through a project funded by Tabuk University in 2014 (project No. 0151-1434-S). The sites of collection included 76 sites covered the region. The sites included a variety of habitat that covered temporary and permanent ponds, streams, wells, reservoirs, and hot springs. Some specimens were identified till species level but others could not be identified due to that they were larvae or immature stages which make the task very difficult. The book is considered as a preliminary guide to identify common zooplankton inhabiting inland waters of Tabuk region and other regions of Saudi Arabia. The need for such a book arises from the fact that few previous attempts were made to record zooplankton in the region. In addition that the region can be considered as a unique habitat in its characteristics as an arid habitat. The nature of the habitat is mainly desert, so it is not easy to reach the areas of collecting without a guide and the majority of sites were temporary lakes or ponds. So, the authors of the book hope that this work will initiate future works in this field in Tabuk and other regions of the Kingdom of Saudi Arabia to cover the whole region. It was found better and more beneficial to add some information about the collected taxa from different references published around the world. The book includes the following main topics: an overview on zooplankton, the investigated sites for collecting zooplankton at Tabuk region, review on zooplankton of Saudi Arabia, List of zooplankton recorded at Tabuk region, description of the common species and the references. The authors hope that the guide will help the taxonomists to identify common zooplankton taxa inhabiting inland water of Tabuk region and other regions in the Kingdom of Saudi Arabia. Consequently, we hope that this identification of the taxa will initiate further studies on this important group of animals. The authors

The main objective of this paper to investigate the diversity of common zooplankton inhabiting inland waters of North West region (Tabuk) of Saudi Arabia. The study covered 76 sites. The results revealed the presence of 38 taxa belonging to phylum Arthropoda and Rotifera. Based on the frequency of occurrence, taxa recorded could be ordered into: constant, accessory and accidental taxa. The constant taxa recorded were represented by one taxon namely: Family Chironomidae. The accessory taxa were represented by 4 taxa: Ostracoda, Diptera pupae, Cyclopoida (Copepoda), and Culicidae larvae. The accidental taxa were represented by the rest of taxa (33 taxa).

2-Alkylmercapto- 4-Chloro-6-phenyl-pyrimidine-5-carbonitrile (4a-c) were synthesized and converted into 2-alkylmercapto 4-mercapto-6- phenyl-pyrimidine-5-carbonitriles (7a-c). Compounds (7a-b) were alkylated with halogenated compounds to afford compounds (8a-g). Compounds (8a-g) underwent Thorpe-Ziegler Cyclization to give thienopyrimidines (9a-g). 5-Amino-2-alkylmercapto-4-phenyl-thieno- [2,3-d]pyrimidine-6-carboxamide derivatives (9a-f) underwent cyclization reaction using triethyl orthoformate to afford pyrimidothienopyrimidines (10a-e).

2-Alkylmercapto- 4-Chloro-6-phenyl-pyrimidine-5-carbonitrile (4a-c) were synthesized and converted into 2-alkylmercapto 4-mercapto-6- phenyl-pyrimidine-5-carbonitriles (7a-c). Compounds (7a-b) were alkylated with halogenated compounds to afford compounds (8a-g). Compounds (8a-g) underwent Thorpe-Ziegler Cyclization to give thienopyrimidines (9a-g). 5-Amino-2-alkylmercapto-4-phenyl-thieno- [2,3-d]pyrimidine-6-carboxamide derivatives (9a-f) underwent cyclization reaction using triethyl orthoformate to afford pyrimidothienopyrimidines (10a-e).

2-Alkylmercapto- 4-Chloro-6-phenyl-pyrimidine-5-carbonitrile (4a-c) were synthesized and converted into 2-alkylmercapto 4-mercapto-6- phenyl-pyrimidine-5-carbonitriles (7a-c). Compounds (7a-b) were alkylated with halogenated compounds to afford compounds (8a-g). Compounds (8a-g) underwent Thorpe-Ziegler Cyclization to give thienopyrimidines (9a-g). 5-Amino-2-alkylmercapto-4-phenyl-thieno- [2,3-d]pyrimidine-6-carboxamide derivatives (9a-f) underwent cyclization reaction using triethyl orthoformate to afford pyrimidothienopyrimidines (10a-e).

2-Alkylmercapto- 4-Chloro-6-phenyl-pyrimidine-5-carbonitrile (4a-c) were synthesized and converted into 2-alkylmercapto 4-mercapto-6- phenyl-pyrimidine-5-carbonitriles (7a-c). Compounds (7a-b) were alkylated with halogenated compounds to afford compounds (8a-g). Compounds (8a-g) underwent Thorpe-Ziegler Cyclization to give thienopyrimidines (9a-g). 5-Amino-2-alkylmercapto-4-phenyl-thieno- [2,3-d]pyrimidine-6-carboxamide derivatives (9a-f) underwent cyclization reaction using triethyl orthoformate to afford pyrimidothienopyrimidines (10a-e).