Consideration on Efficient Recombinant Protein Production: Focus on Substrate Protein-Specific Compatibility Patterns of Molecular Chaperones

The Protein Journal - Expression of recombinant proteins requires at times the aid of molecular chaperones for efficient post-translational folding into functional structure. However, predicting...     

Studies of the implosion of cylindrical fiber arrays on the Angara-5-1 facility

Results are presented from experimental studies of the implosion of cylindrical kapron fiber arrays with addition of high- and medium-Z metal wires (tungsten, aluminum). The experiments were carried out on the Angara-5-1 facility at currents of 3–4 MA. The ablation rate in kapron fiber arrays is estimated and compared with that in tungsten wire arrays.     

Dynamics of Heterogeneous Liners with Prolonged Plasma Creation

Prolonged plasma creation in heterogeneous liners, in which the liner substance is separated into two phase states (a hot plasma and a cold skeleton), is investigated both experimentally and theoretically. This situation is typical of multiwire, foam, and even gas liners in high-current high-voltage facilities. The main mechanisms governing the rate at which the plasma is created are investigated, and the simplest estimates of the creation rate are presented. It is found that, during prolonged plasma creation, the electric current flows through the entire cross section of the produced plasma shell, whose thickness is comparable with the liner radius; in other words, a current skin layer does not form. During compression, such a shell is fairly stable because of its relatively high resilience. It is shown that, under certain conditions, even a thick plasma shell can be highly compressed toward the discharge axis. A simplified numerical simulation of the compression of a plasma shell in a liner with prolonged plasma creation is employed in order to determine the conditions for achieving regimes of fairly compact and relatively stable radial compression of the shell.     

Scavenger Receptors SR-AI/II and MARCO limit pulmonary dendritic cell migration and allergic airway inflammation

The class A scavenger receptors (SR-A) MARCO and SR-AI/II are expressed on lung macrophages (MPhis) and dendritic cells (DCs) and function in innate defenses against inhaled pathogens and particles. Increased expression of SR-As in the lungs of mice in an OVA-asthma model suggested an additional role in modulating responses to an inhaled allergen. After OVA sensitization and aerosol challenge, SR-AI/II and MARCO-deficient mice exhibited greater eosinophilic airway inflammation and airway hyperresponsiveness compared with wild-type mice. A role for simple SR-A-mediated Ag clearance ("scavenging") by lung MPhis was excluded by the observation of a comparable uptake of fluorescent OVA by wild-type and SR-A-deficient lung MPhis and DCs. In contrast, airway instillation of fluorescent Ag revealed a significantly higher traffic of labeled DCs to thoracic lymph nodes in SR-A-deficient mice than in controls. The increased migration of SR-A-deficient DCs was accompanied by the enhanced proliferation in thoracic lymph nodes of adoptively transferred OVA-specific T cells after airway OVA challenge. The data identify a novel role for SR-As expressed on lung DCs in the down-regulation of specific immune responses to aeroallergens by the reduction of DC migration from the site of Ag uptake to the draining lymph nodes.     

Immunostimulatory CpG oligonucleotides abrogate allergic susceptibility in a murine model of maternal asthma transmission

We tested the potential of CpG oligodeoxynucleotides (ODN) to reverse the increased susceptibility to allergic airways disease in neonatal mice in a model of maternal transmission of asthma risk. Offspring of OVA-sensitized and challenged BALB/c mother mice were subjected to an intentionally suboptimal sensitization protocol that has minimal effects on normal mice, but results in airway hyperresponsiveness (AHR) and airway inflammation (AI) in babies of asthmatic mother mice. We evaluated pulmonary function and AI in CpG- or control ODN-treated offspring. CpG treatment of neonates on day 4 of life prevents the AHR otherwise seen in this model (enhanced pause at 100 mg/ml methacholine: CpG, 0.9 +/- 0.1; ODN control, 3.8 +/- 0.6; n = 62; p < 0.005). It also prevented the development of AI, as evident in decreased bronchoalveolar lavage eosinophilia (CpG, 1.2 +/- 0.3%; ODN, 31.4 +/- 4.1%; n = 56; p < 0.005), diminished the severity of AI on histopathology, and resulted in lower IL-5 levels in bronchoalveolar lavage fluid. The effect of CpG persisted for at least 4-6 wk and was allergen independent. Treatment with CpG just before OVA aerosol challenge also prevented allergic responses. The data support the potential for immunomodulatory therapy with CpG in early life to reduce susceptibility to asthma.     

Spleen and thymus lymphoid tissue in hypoxia (a biometric study)

The spleen and thymus have been studied macro- and microscopically in rats (180-200 g body mass) on the 1st, 3d, 5th, 7th, 14th and 28th days of adaptation to a decreased atmospheric pressure in the altitude chamber corresponding to lifting to 5,000 and 7,500 m (after a preliminary gradual acclimatization) and on the 14th, 28th, 42d, 56th days of readaptation. A relative mass of the organs, the white pulp section area--the transversal section area of the spleen ratio, the summation section area of its lymph nodules have been estimated. In the thymus the cortico-medullary index (CMI) has been defined. A relative mass of the spleen increases during the first week of hypoxia, and during adaptation period it somewhat decreases and stabilizes, remaining higher than in the control. At the altitude of 5,000 m the cross section area of the lymph nodules decreases by 17% on the 28th adaptation day and at the altitude of 7,500 m--by 27% beginning from the 14th up to the 28th adaptation days. In the thymus the CMI, after some decrease during the first days of hypoxia at the altitude of 5,000 m, increases and normalizes on the 28th adaptation day, and at the altitude of 7,500 m stabilizes on the 14th - 28th days of hypoxia. When the rats are at the altitudes of 5,000 and 7,500 m the thymus lymphoid tissue reacts more quickly to the hypoxia effect and much sooner normalizes during the readaptation period than does the white pulp of the spleen. The main changes in the lymphoid tissue of the spleen and thymus take place on the 7th - 28th days of hypoxia.     

Study of soft X-ray emission from Z-pinches with a complex atomic composition

Results are presented from experimental studies of Z-pinches produced by implosion of aluminum and tungsten cylindrical wire arrays in the Angara-5-1 facility. The electron temperature T _e and density n _e of the high-temperature pinch plasma have been determined by analyzing line emission from multicharged ions. For the same mass and radius of the array and the same number of wires in it, the intensity of line emission of H- and He-like Al ions from an imploded Al + W wire array containing even a small amount of tungsten (7 wt %) is one order of magnitude lower than that from an Al array. As the W content increases, the total soft X-ray (SXR) yield increases, while the duration of the SXR pulse decreases. For the 30% W content in the array, the power and duration of the SXR pulse are nearly the same as those recorded during the implosion of a W array with the same linear mass and radius and the same number of wires. Results are also presented from experiments with nested wire arrays in which the outer and inner shells were made of Al and W wires, respectively. It is found that, in this case, the effect of tungsten on the line emission of aluminum is much weaker than that in experiments with arrays in which tungsten and aluminum wires were placed in the same shell, even if the mass of the inner (tungsten) shell was larger than that of the outer (aluminum) one. At the same time, the inner W shell plays a significant role in the implosion dynamics of a nested wire array, reducing the duration of the SXR pulse and increasing the SXR power.     

Photocurable Hydrogels Containing Spidroin or Fibroin

Photocurable biocompatible hydrogels were fabricated from methacrylated gelatin and silk proteins (a recombinant analogue of spidroin from Nephila clavipes spider web and fibroin from the cocoons of the silkworm Bombyx mori). These polymers are widely applicable in tissue engineering due to their biocompatibility and biodegradability. Hydrogels were fabricated using two different methods that allowed to obtain either the macroscopic scaffolds or microstructures with a defined shape. Three-dimensional hydrogel samples were prepared via monomers solution photopolymerization for 10 min. As a result, the disk-shaped samples of hydrogels approximately 13 mm in diameter were fabricated. Their porous structure was confirmed by scanning electron microscopy. Microstructures were formed on coverslips using an Eclipse Ti-E microscope equipped with an A1 confocal module (Nikon, Japan) and 405 nm laser. This approach allows to control the topographic features of the obtained substrates, and it is viable for creating the micropattern surfaces to reveal for studying the interaction of cells with a substrate.