Lipid-transfer proteins (LTP) are basic, 9-kDa proteins present in high amounts (as much as 4% of the total soluble proteinss) in higher plants. LTPs can enhance the in vitro transfer of phospholipids between membranes and can bind acyl chains. On the basis of these properties, LTPs were thought to participate in membrane biogenesis and regulation of the intracellular fatty acid pools. However, the isolation of several cDNAs and genes revealed the presence of a signal peptide indicating that LTPs could enter the secretory pathway. They were found to be secreted and located in the cell wall. Thus, novel roles were suggested for plant LTPs: participation in cutin formation, embryogenesis, defense reactions against phytopathogens, symbiosis, and the adaptation of plants to various environmental conditions. The validity of these suggestions needs to be determined, in the hope that they will elucidate the role of this puzzling family of plant proteins.

Lipid-transfer proteins in plants

Circadian (∼24 hour) clocks are fundamentally important for coordinated physiology in organisms as diverse as cyanobacteria and humans All current models of the molecular circadian clockwork in eukaryotic cells are based on transcription–translation feedback loops Non-transcriptional mechanisms in the clockwork have been difficult to study in mammalian systems We circumvented these problems by developing novel assays using human red blood cells, which have no nucleus (or DNA) and therefore cannot perform transcription Our results show that transcription is not required for circadian oscillations in humans, and that non-transcriptional events seem to be sufficient to sustain cellular circadian rhythms Using red blood cells, we found that peroxiredoxins, highly conserved antioxidant proteins, undergo ∼24-hour redox cycles, which persist for many days under constant conditions (that is, in the absence of external cues) Moreover, these rhythms are entrainable (that is, tunable by environmental stimuli) and temperature-compensated, both key features of circadian rhythms We anticipate that our findings will facilitate more sophisticated cellular clock models, highlighting the interdependency of transcriptional and non-transcriptional oscillations in potentially all eukaryotic cells Circadian clocks are critical timing regulators of physiology and behaviour that are ubiquitous in eukaryotes Most mechanistic models of the clock are based on transcription cycles, but evidence for post-translational regulation has recently surfaced in plants and cyanobacteria Two groups now demonstrate a role for the oxidation of peroxiredoxin proteins in maintaining an entrainable oscillation in human red blood cells and in the unicellular alga Ostreococcus tauri These data suggest a role for non-transcriptional mechanisms in clock models and open the door to future work exploring the connections between the transcriptional and non-transcriptional circadian machinery Circadian clocks are critical timing regulators of physiology and behaviour that are ubiquitous in eukaryotes Most mechanistic models of the this clock are based on transcription cycles, but some evidence for post-translational regulation has recently surfaced in plants and cyanobacteria This is one of two groups demonstrating a role for the oxidation of peroxiredoxin proteins in maintaining an entrainable oscillation in human red blood cells and a unicellular alga These data indicate a role for non-transcriptional mechanisms in clock models and open the door to future work exploring the connections between the transcriptional and non-transcriptional circadian machinery

Circadian clocks in human red blood cells

Oxygen Carriers (“Blood Substitutes”)Raison d'Etre, Chemistry, and Some Physiology Blut ist ein ganz besondrer Saft1

Plants have considerable potential for the production of biopharmaceutical proteins and peptides because they are easily transformed and provide a cheap source of protein. Several biotechnology companies are now actively developing, field testing, and patenting plant expression systems, while clinical trials are proceeding on the first biopharmaceuticals derived from them. One transgenic plant-derived biopharmaceutical, hirudin, is now being commercially produced in Canada for the first time. Product purification is potentially an expensive process, and various methods are currently being developed to overcome this problem, including oleosin-fusion technology, which allows extraction with oil bodies. In some cases, delivery of a biopharmaceutical product by direct ingestion of the modified plant potentially removes the need for purification. Such biopharmaceuticals and edible vaccines can be stored and distributed as seeds, tubers, or fruits, making immunization programs in developing countries cheaper and potentially easier to administer. Some of the most expensive biopharmaceuticals of restricted availability, such as glucocerebrosidase, could become much cheaper and more plentiful through production in transgenic plants.

Transgenic plants as factories for biopharmaceuticals.

In the science and engineering communities, the nanoscience revolution is intensifying. As many types of nanomaterials are becoming more reliably synthesized, they are being used for novel applications in all branches of nanoscience and nanotechnology. Since it is sometimes desirable for single nanomaterials to perform multiple functions simultaneously, multicomponent nanomaterials, such as core-shell, alloyed, and striped nanoparticles, are being more extensively researched. Nanoscientists hope to design multicomponent nanostructures and exploit their inherent multiple functionalities for use in many novel applications. This review highlights recent advances in the synthesis of multisegmented one-dimensional nanorods and nanowires with metal, semiconductor, polymer, molecular, and even gapped components. It also discusses the applications of these multicomponent nanomaterials in magnetism, self-assembly, electronics, biology, catalysis, and optics. Particular emphasis is placed on the new materials and devices achievable using these multicomponent, rather than single-component, nanowire structures.

Multisegmented One‐Dimensional Nanorods Prepared by Hard‐Template Synthetic Methods

Human haemoglobin from transgenic tobacco

One of the main difficulties with blood substitutes based on hemoglobin (Hb) solutions is the auto-oxidation of the hemes, a problem aggravated by the dimerization of Hb tetramers. We have employed a method to study the oxyHb tetramer-dimer equilibrium based on the rate of auto-oxidation as a function of protein concentration. The 16-fold difference in dimer and tetramer auto-oxidation rates (in 20 mM phosphate buffer at pH 7.0, 37 degrees C) was exploited to determine the fraction dimer. The results show a transition of the auto-oxidation rate from low to high protein concentrations, allowing the determination of the tetramer-dimer dissociation coefficient K4,2 = [Dimer] 2/[Tetramer]. A 14-fold increase in K4,2 was observed for addition of 10 mM of the allosteric effector inositol hexaphosphate (IHP). Recombinant hemoglobins (rHb) were genetically engineered to obtain Hb with a lower oxygen affinity than native Hb (Hb A). The rHb alpha2beta2 [(C7) F41Y/(G4) N102Y] shows a fivefold increase in K4,2 at pH 7.0, 37 degrees C. An atmosphere of pure oxygen is necessary in this case to insure fully oxygenated Hb. When this condition is satisfied, this method provides an efficient technique to characterize both the tetramer-dimer equilibrium and the auto-oxidation rates of various oxyHb. For low oxygen affinity Hb equilibrated under air, the presence of deoxy subunits accelerates the auto-oxidation. Although a full analysis is complicated, the auto-oxidation studies for air equilibrated samples are more relevant to the development of a blood substitute based on Hb solutions. The double mutants, rHb alpha2beta2 [(C7) F41Y/(G4) N102A] and rHb alpha2beta2 [(C7) F41Y/(E10) K66T], show a lower oxygen affinity and a higher rate of oxidation than Hb A. Simulations of the auto-oxidation rate versus Hb concentration indicate that very high protein concentrations are required to observe the tetramer auto-oxidation rate. Because the dimers oxidize much more rapidly, even a small fraction dimer will influence the observed oxidation rate.

https://www.onlinelibrary.wiley.com/doi/pdf/10.1002/pro.5560070316

Tetramer‐dimer equilibrium of oxyhemoglobin mutants determined from auto‐oxidation rates

Purification process of recombinant monoclonal antibodies with mixed mode chromatography

https://escholarship.org/content/qt7xc2j6r8/qt7xc2j6r8.pdf?t=oph5sa

Wilfrid Dieryck

Papers

Human haemoglobin from transgenic tobacco

Tetramer‐dimer equilibrium of oxyhemoglobin mutants determined from auto‐oxidation rates

Purification process of recombinant monoclonal antibodies with mixed mode chromatography

Selective Tuning of Elastin-like Polypeptide Properties via Methionine/Oxidation

Structure-activity relationship of human liver-expressed antimicrobial peptide 2