Infection with Phloem Limited Abutilon Mosaic Virus Causes Localized Carbohydrate Accumulation in Leaves of Abutilon striatum: Relationships to Symptom Development and Effects on Chlorophyll Fluorescence Quenching During Photosynthetic Induction

Abstract: Infection with phloem limited Abutilon Mosaic Virus caused localized carbohydrate accumulation (high levels of starch, sucrose, and hexoses) in leaves of Abutilon striatum during early symptom development. In mature leaves with attenuated symptoms, tissues showing faint vein-clearing had markedly higher carbohydrate contents than uniformly green areas of the same leaf. A similar pattern of carbohydrate accumulation was found in pale-green mosaics in mature leaves with overt symptoms when compared to green-islands of the same leaf, but overnight carbohydrate loses were comparable to controls. Because leaves with attenuated symptoms showed no further symptom development whereas the pale-green mosaics became yellow and eventually necrotic in leaves with overt symptoms, it seems unlikely that carbohydrate accumulation following impaired translocation was responsible for symptom expression. High carbohydrate status in leaves with attenuated symptoms had little effect on nonphotochemical quenching during early stages of photosynthetic induction. In leaves with overt symptoms, areas of high carbohydrate status with pale-green mosaics showed markedly slower nonphotochemical quenching. Early symptom areas of young leaves, and advanced symptom areas of mature leaves had low starch contents but were otherwise similar to controls in carbohydrate status. Impaired nonphotochemical quenching in these tissues tended to reflect the state of symptom development, rather than carbohydrate status. Plants with overt symptoms grew about half as fast as plants with attenuated symptoms.     

Multimodal peptide ligand extracts parvovirus from interface in affinity aqueous two-phase system

Aqueous two-phase systems (ATPS) have found various applications in bioseparations and microencapsulation. The primary goal of this technique is to partition target biomolecules in a preferred phase, rich in one of the phase-forming components. However, there is a lack of understanding of biomolecule behavior at the interface between the two phases. Biomolecule partitioning behavior is studied using tie-lines (TL), where each TL is a group of systems at thermodynamic equilibrium. Across a TL, a system can either have a bulk PEG-rich phase with citrate-rich droplets, or the opposite can occur. We found that porcine parvovirus (PPV) was recovered at a higher amount when PEG was the bulk phase and citrate was in droplets and that the salt and PEG concentrations are high. To improve the recovery, A PEG 10 kDa-peptide conjugate was formed using the multimodal WRW ligand. When WRW was present, less PPV was caught at the interface of the two-phase system, and more was recovered in the PEG-rich phase. While WRW did not significantly increase the PPV recovery in the high TL system, which was found earlier to be optimal for PPV recovery, the peptide did greatly enhance recovery at a lower TL. This lower TL has a lower viscosity and overall system PEG and citrate concentration. The results provide both a method to increase virus recovery in a lower viscosity system, as well as provide interesting thoughts into the interfacial phenomenon and how to recover virus in a phase and not at the interface.