ABSTRACT
In order to explore the effect of influent PO43--P concentration on the relationship of phosphorus remove performance and sludge settleability, three sequencing batch reactors (SBRs) operated as anaerobic/aerobic mode were used to treat wastewater with different PO43--P concentrations (same COD), and the organic loading rate (OLR) was changed through adjusting the anaerobic (aerobic) duration. The sludge settleability, nutrients removal, and microorganism species were investigated. The results showed that when the influent PO43--P were 4.3 mg·L-1 and 8.6 mg·L-1, increasing the OLR through decreasing aerobic duration could significantly improve sludge settleability, while decreasing anaerobic duration could not. It was found that increase the OLR could promote the denitrification compete for carbon sources with phosphorus release process by inhibiting the accumulation of NO2--N, leading to the decrease of phosphorus removal ability. When the influent PO43--P was 17.2 mg·L-1, sufficient nitrification was beneficial to enrich denitrifying phosphorus accumulating bacteria (DPAO), and the activities of Thauera and Flavobacterium (DPAO) were stronger. Therefore, increasing influent PO43--P concentration and reducing aerobic duration could help phosphorus accumulating bacteria (PAO) compete with denitrification for COD and enrich DPAO, thus reducing carbon source consumption.
Subject(s)
Denitrification , Sewage , Sewage/microbiology , Waste Disposal, Fluid , Bioreactors/microbiology , Nitrogen , Nitrification , Phosphorus , Wastewater , Carbon , Nutrients , BacteriaABSTRACT
To study the agricultural production of biosimilar antibodies, trastuzumab (Herceptin) was expressed in Nicotiana benthamiana using the magnICON viral-based transient expression system. Immunoblot analyses of crude plant extracts revealed that trastuzumab accumulates within plants mostly in the fully assembled tetrameric form. Purification of trastuzumab from N. benthamiana was achieved using a scheme that combined ammonium sulfate precipitation with affinity chromatography. Following purification, the specificity of the plant-produced trastuzumab for the HER2 receptor was compared with Herceptin and confirmed by western immunoblot. Functional assays revealed that plant-produced trastuzumab and Herceptin have similar in vitro antiproliferative effects on breast cancer cells that overexpress HER2. Results confirm that plants may be developed as an alternative to traditional antibody expression systems for the production of therapeutic mAbs.
Subject(s)
Adenocarcinoma/drug therapy , Antibodies, Monoclonal/biosynthesis , Antibodies, Monoclonal/pharmacology , Antineoplastic Agents/metabolism , Antineoplastic Agents/pharmacology , Nicotiana/metabolism , Receptor, ErbB-2/metabolism , Adenocarcinoma/metabolism , Antibodies, Monoclonal/chemistry , Antibodies, Monoclonal/genetics , Antibodies, Monoclonal, Humanized , Antineoplastic Agents/chemistry , Antineoplastic Agents/isolation & purification , Bioreactors , Cell Line, Tumor , Cell Proliferation/drug effects , Humans , Plantibodies/chemistry , Plantibodies/genetics , Plantibodies/metabolism , Plantibodies/pharmacology , Plants, Genetically Modified/metabolism , Nicotiana/genetics , TrastuzumabABSTRACT
Botulinum neurotoxins (BoNTs) are the most poisonous substances known and are thus classified as high-risk threats for use as bioterror agents. To examine the potential of transgenic plants as bioreactors for the production of BoNT antidotes, we transformed tobacco with an optimized, synthetic gene encoding a botulinum neurotoxin A (BoNT/A) neutralizing single-chain Fv (scFv) recombinant antibody fragment. In vitro mouse muscle twitch assays demonstrated the functional utility of this scFv extracted from tobacco for neutralizing the paralytic effects of BoNT/A at neuromuscular junctions. Based on the efficiency of the scFv capture process and the dose required to antidote a human being, 1-2 ha of this tobacco could yield up to 4 kg of scFv, which would be enough to contribute to the manufacture of 1,000,000 therapeutic doses of a monoclonal antibody (mAb) cocktail capable of neutralizing the effects of BoNT poisoning. Transgenic plants could provide an inexpensive production platform for expression of multiple mAbs toward the creation of polyclonal therapies (i.e. pooled mAbs) as the next improvement in recombinant antibody therapy.
Subject(s)
Botulinum Toxins, Type A/immunology , Clostridium botulinum/genetics , Immunoglobulin Fragments/metabolism , Plants, Genetically Modified/metabolism , Botulinum Toxins, Type A/antagonists & inhibitors , Botulinum Toxins, Type A/genetics , Clostridium botulinum/chemistry , Clostridium botulinum/immunology , Immunoglobulin Fragments/genetics , Immunoglobulin Fragments/immunology , Pharmaceutical Preparations , Plants, Genetically Modified/genetics , Recombinant Fusion Proteins/immunology , Recombinant Fusion Proteins/metabolism , NicotianaABSTRACT
In order to create a novel mechanism for herbicide resistance in plants, we expressed a single-chain antibody fragment (scFv) in tobacco with specific affinity to the auxinic herbicide picloram. Transgenic tobacco plants and seedlings expressing this scFv against picloram were protected from its effect in a dose-dependent manner. This is the first successful use of an antibody to confer in vivo resistance to a low molecular weight xenobiotic (i.e. < 1000 Da). Our results suggest the possibility for a generic antibody-based approach to create crops resistant to low molecular weight xenobiotics for subsequent use in the bioremediation of contaminated soils, crop protection and as novel selectable markers.
