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A novel kind of lutein-protein complex (LPC) was extracted from heterotrophic Chlorella vulgaris through aqueous extraction. The purification procedure contained solubilization of thylakoid proteins by a zwitterionic detergent CHAPS, anion exchange chromatography and gel filtration chromatography. Both wavelength scanning and HPLC analysis confirmed that lutein was the major pigment of the protein-based complex, and the mass ratio of lutein and protein was determined to be 9.72 : 100. Besides showing lipid peroxidation inhibition activity in vitro, LPC exerted significant antioxidant effects against ABTS and DPPH radicals with IC50 of 2.90 and 97. 23 μg mL(-1), respectively. Meanwhile, in vivo antioxidant activity of the complex was evaluated using the mice hepatotoxicity model; LPC significantly suppressed the carbon tetrachloride-induced elevation of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities, and decreased hepatic malondialdehyde (MDA) levels and the hepatosomatic index. Moreover, LPC could effectively restore the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) in the treated mice livers. Our findings further the progress in the research of natural protein-based lutein complexes, suggesting that LPC has the potential in hepatoprotection against chemical induced toxicity and in increasing the antioxidant capacity of the defense system in the human body.

Ribosome-inactivating proteins (RIPs) either single-chain (type 1) or two-chain (type 2) are frequent in plants, often in multiple forms. They are RNA N-glycosidases, have antiviral, antifungal and insecticidal activity. Their expression in plants is increased under stressful conditions. They are investigated for practical applications in medicine and in agriculture. In medicine, RIPs have been linked to, or fused with, appropriate antibodies or other carriers to form "immunotoxins" or other conjugates specifically toxic to the cells target of the carrier, with the aim of eliminating malignant or other undesired cells. In agriculture, it has been observed that an enhanced expression of RIPs confers to plants an increased resistance to viruses, fungi, insects, and also to drought and salinity., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Viruses of the family Coronaviridae have recently emerged through zoonotic transmission to become serious human pathogens. The pathogenic agent responsible for severe acute respiratory syndrome (SARS), the SARS coronavirus (SARS-CoV), is a member of this large family of positive-strand RNA viruses that cause a spectrum of disease in humans, other mammals, and birds. Since the publicized outbreaks of SARS in China and Canada in 2002-2003, significant efforts successfully identified the causative agent, host cell receptor(s), and many of the pathogenic mechanisms underlying SARS. With this greater understanding of SARS-CoV biology, many researchers have sought to identify agents for the treatment of SARS. Here we report the utility of the potent antiviral protein griffithsin (GRFT) in the prevention of SARS-CoV infection both in vitro and in vivo. We also show that GRFT specifically binds to the SARS-CoV spike glycoprotein and inhibits viral entry. In addition, we report the activity of GRFT against a variety of additional coronaviruses that infect humans, other mammals, and birds. Finally, we show that GRFT treatment has a positive effect on morbidity and mortality in a lethal infection model using a mouse-adapted SARS-CoV and also specifically inhibits deleterious aspects of the host immunological response to SARS infection in mammals.

A number of lectins that bind high-mannose carbohydrates on the surface of the envelopes of virus has been found to have antiviral activity. In particular, some algal lectins such as Cyanovirin-N, Microcystis viridis lectin, Scytovirin, Griffithsin and Oscillatoria agardhii agglutinin, exhibit high anti-HIV activity, and provide an alternative route to prevention of HIV transmission. This review focuses on the structural property, antiviral activity and possible mechanism of these lectins, and future challenges for potential prophylactic or therapeutic applications are also discussed.

Antibody-based therapeutics have had great success over the last few years, and continue to be one of the fastest growing sectors of drug development. The efficacy and specificity of antibody-based drugs makes them ideal candidates for new drug development, but the specificity of these drugs comes from their complexity, and this complexity makes antibodies very expensive to produce. To address this problem, the authors have developed a system for the expression of recombinant proteins using the unicellular eukaryotic green algae, Chlamydomonas reinhardtii. As proof of concept, the authors have engineered microalgae to produce several forms of a human IgA antibody directed against herpes simplex virus. The expression of human monoclonal antibodies in C. reinhardtii offers an attractive alternative to traditional mammalian-based expression systems, as both the plastid and nuclear genomes are easily and quickly transformed, and the production of proteins in algae has an inherently low cost of capitalisation and production.