ABSTRACT
Recombinant protein (RP) production from Escherichia coli has been extensively studied to find strategies for increasing product yields. The thermoinducible expression system is commonly ...employed at the industrial level to produce various RPs, which avoids the addition of chemical inducers, thus minimizing contamination risks. Multiple aspects of the molecular origin and biotechnological uses of its regulatory elements (pL/pR promoters and cI857 thermolabile repressor) derived from bacteriophage λ provide knowledge to improve the bioprocesses using this system. Here, we discuss the main aspects of the potential use of the λpL/pR-cI857 thermoinducible system for RP production in E. coli, focusing on the approaches of investigations that have contributed to the advancement of this expression system. Metabolic and physiological changes that occur in the host cells caused by heat stress and RP overproduction are also described. Therefore, the current scenario and the future applications of systems that use heat to induce RP production are discussed to understand the relationship between the activation of the bacterial heat shock response, RP accumulation and its possible aggregation to form inclusion bodies.
This review highlights the use of Escherichia coli thermoinducible system for recombinant protein production, and the relationship between the heat shock response, the concomitant expression of chaperones and formation of inclusion bodies.
We describe a sibling pair of Mennonite origin born from consanguineous parentage with a likely new phenotype of limb–girdle muscular dystrophy, short stature, ptosis, and tracheomalacia. Exome ...sequencing in the affected subjects identified a novel homozygous RAB3GAP2 missense variant as the potential causal variant. As RAB3GAP2 has been recently shown to be involved in the autophagy process, we analyzed patient‐derived fibroblasts by fluorescence microscopy and demonstrated defective autophagic flux under rapamycin and serum starvation conditions when compared with wild‐type cells. The phenotype in the siblings described here is distinct from Martsolf and Warburg's micro syndromes, the currently known diseases arising from RAB3GAP2 pathogenic variants. Thus, this work describes a potentially novel recessive phenotype associated with a RAB3GAP2 defect and manifesting as a muscular dystrophy–short stature disorder with no ocular anomalies. Functional analyses indicated defective autophagy in patient‐derived fibroblasts, supporting the involvement of RAB3GAP2 in the etiology of this disorder. Our results contribute to a better characterization of the Martsolf/micro spectrum phenotype.
Camel production in Saudi Arabia is severely affected by various diseases and by inadequate veterinary services. Ticks and tick-borne pathogens (TBPs) affect the health and wellbeing of camels ...consequently diminishing their productivity and performances. In addition, camels may act as hosts for TBPs (e.g. Anaplasma phagocytophilum) causing diseases in humans. The current study aimed to determine the prevalence of ixodid ticks and molecularly investigate the associated pathogens in camels from Saudi Arabia.
Blood and tick samples were collected from camels (n = 170) in Riyad Province of Saudi Arabia. Ticks were morphologically identified, and blood of camels were molecularly screened for apicomplexan (i.e. Babesia spp., Theileria spp., Hepatozoon spp.) and rickettsial parasites (i.e. Ehrlichia spp. and Anaplasma spp.).
Of the 170 camels examined, 116 (68.2%; 95% CI: 60.9-75.1%) were infested by ticks with a mean intensity of 2.53 (95% CI: 2.4-2.6). In total of 296 ticks collected, Hyalomma dromedarii was the most prevalent (76.4%), followed by Hyalomma impeltatum (23.3%) and Hyalomma excavatum (0.3%). Of the tested animals, 13 (7.6%; 95% CI: 4.3-12.8%) scored positive to at least one TBP, with Anaplasma platys (5.3%; 95% CI: 2.7-9.9%) being the most prevalent species, followed by Anaplasma phagocytophilum, Anaplasma sp., Ehrlichia canis and Hepatozoon canis (0.6% each; 95% CI: 0.04-3.4%). None of the camels were found to be co-infected with more than one pathogen. All samples tested negative for Babesia spp. and Theileria spp.
The present study reveals the occurrence of different tick species and TBPs in camels from Saudi Arabia. Importantly, these camels may carry A. phagocytophilum and A. platys, representing a potential risk to humans.
Objective Magnetic resonance imaging (MRI) often demonstrates brain lesions in neuropsychiatric systemic lupus erythematosus (NPSLE). The present study compared postmortem histopathology with ...premortem MRI in NPSLE. Methods Two hundred subjects with NPSLE were studied prospectively with MRI over a 10-year period during which 22 subjects died. In 14 subjects, a brain autopsy with histopathology, that permitted direct comparison with premortem MRI, was successfully obtained. Surface anatomy was used to determine the approximate location of individual lesions. Results Premortem MRI findings in fatal NPSLE were small focal white matter lesions (100%), cortical atrophy (64%), ventricular dilation (57%), cerebral edema (50%), diffuse white matter abnormalities (43%), focal atrophy (36%), cerebral infarction (29%), acute leukoencephalopathy (25%), intracranial hemorrhage (21%), and calcifications (7%). Microscopic findings in fatal NPSLE included global ischemic changes (57%), parenchymal edema (50%), microhemorrhages (43%), glial hyperplasia (43%), diffuse neuronal/axonal loss (36%), resolved cerebral infarction (33%), microthomboemboli (29%), blood vessel remodeling (29%), acute cerebral infarction (14%), acute macrohemorrhages (14%), and resolved intracranial hemorrhages (7%). Cortical atrophy and ventricular dilation seen by MRI accurately predicted brain mass at autopsy (r = −0.72, P = 0.01, and r = −0.77, P = 0.01, respectively). Cerebral autopsy findings, including infarction, cerebral edema, intracranial hemorrhage, calcifications, cysts, and focal atrophy, were also predicted accurately by premortem MRI. Conclusion Brain lesions in NPSLE detected by MRI accurately represent serious underlying cerebrovascular and parenchymal brain injury on pathology.
Additive nanotechnology enable curvilinear and three-dimensional (3D) magnetic architectures with tunable topology and functionalities surpassing their planar counterparts. Here, we experimentally ...reveal that 3D soft magnetic wireframe structures resemble compact manifolds and accommodate magnetic textures of high order vorticity determined by the Euler characteristic, χ. We demonstrate that self-standing magnetic tetrapods (homeomorphic to a sphere; χ = + 2) support six surface topological solitons, namely four vortices and two antivortices, with a total vorticity of + 2 equal to its Euler characteristic. Alternatively, wireframe structures with one loop (homeomorphic to a torus; χ = 0) possess equal number of vortices and antivortices, which is relevant for spin-wave splitters and 3D magnonics. Subsequent introduction of n holes into the wireframe geometry (homeomorphic to an n-torus; χ < 0) enables the accommodation of a virtually unlimited number of antivortices, which suggests their usefulness for non-conventional (e.g., reservoir) computation. Furthermore, complex stray-field topologies around these objects are of interest for superconducting electronics, particle trapping and biomedical applications.
In semiarid climate soils, the establishment of a plant cover is fundamental to avoid degradation and desertification processes. A better understanding of the ability of plants to promote soil ...microbial processes in these conditions is necessary for successful soil reclamation. Six different plant species were planted in a semiarid soil, in order to know which species are the most effective for the reclamation of semiarid areas. Six years after planting, the rhizosphere soils were studied by measuring chemical (pH, electrical conductivity, total organic carbon and other carbon fractions), physical (% of saggregates), microbiological (microbial biomass carbon and soil respiration), and biochemical (dehydrogenase, phosphatase, β-glucosidase and urease activities) parameters. In general, in all the soil–plant systems plant nutrients, organic matter and microbial activity increased compared to the control soil. For some species, such as
Rhamnus lycioides, the increase in the total organic carbon content (TOC) in the rhizosphere zone was almost 200%. A positive correlation was found between TOC and water-soluble carbon (
p<0.001); both parameters were negatively correlated with electrical conductivity. Microbial biomass carbon and soil respiration were highest in the rhizosphere of
Stipa tenacissima (98% and 60%, respectively, of increase on soil control values) and
Rosmarinus officinalis (94% and 51%, respectively, of increase on soil control values). These microbiological parameters were correlated with the percentage of stable aggregates (
p<0.01). Enzyme activities were affected by the rhizosphere, their values depending on the shrub species.
Domain wall propagation in modulated-diameter cylindrical nanowires is a key phenomenon to be studied with a view to designing three-dimensional magnetic memory devices. This paper presents a ...theoretical study of transverse domain wall behavior under the influence of a magnetic field within a cylindrical nanowire with diameter modulations. In particular, domain wall pinning close to the diameter modulation was quantified, both numerically, using finite element micromagnetic simulations, and analytically. Qualitative analytical model for gently sloping modulations resulted in a simple scaling law which may be useful to guide nanowire design when analyzing experiments. It shows that the domain wall depinning field value is proportional to the modulation slope.
The iron sulfide mineral greigite, Fe3S4, has shown promising capability as a hydrogenating catalyst, in particular in the reduction of carbon dioxide to produce small organic molecules under mild ...conditions. We employed density functional theory calculations to investigate the {001},{011} and {111} surfaces of this iron thiospinel material, as well as the production of hydrogen ad-atoms from the dissociation of water molecules on the surfaces. We systematically analysed the adsorption geometries and the electronic structure of both bare and hydroxylated surfaces. The sulfide surfaces presented a higher flexibility than the isomorphic oxide magnetite, Fe3O4, allowing perpendicular movement of the cations above or below the top atomic sulfur layer. We considered both molecular and dissociative water adsorption processes, and have shown that molecular adsorption is the predominant state on these surfaces from both a thermodynamic and kinetic point of view. We considered a second molecule of water which stabilizes the system mainly by H-bonds, although the dissociation process remains thermodynamically unfavourable. We noted, however, synergistic adsorption effects on the Fe3S4{001} owing to the presence of hydroxyl groups. We concluded that, in contrast to Fe3O4, molecular adsorption of water is clearly preferred on greigite surfaces.
Chinese hamster ovary cells have been the workhorse for the production of recombinant proteins in mammalian cells. Since biochemical, cellular and omics studies are usually affected by the lack of ...suitable fractionation procedures to isolate compartments from these cells, differential and isopycnic centrifugation based techniques were characterized and developed specially for them. Enriched fractions in intact nuclei, mitochondria, peroxisomes, cis-Golgi, trans-Golgi and endoplasmic reticulum (ER) were obtained in differential centrifugation steps and subsequently separated in discontinuous sucrose gradients. Nuclei, mitochondria, cis-Golgi, peroxisomes and smooth ER fractions were obtained as defined bands in 30-60% gradients. Despite the low percentage represented by the microsomes of the total cell homogenate (1.7%), their separation in a novel sucrose gradient (10-60%) showed enough resolution and efficiency to quantitatively separate their components into enriched fractions in trans-Golgi, cis-Golgi and ER. The identity of these organelles belonging to the classical secretion pathway that came from 10-60% gradients was confirmed by proteomics. Data are available via ProteomeXchange with identifier PXD019778. Components from ER and plasma membrane were the most frequent contaminants in almost all obtained fractions. The improved sucrose gradient for microsomal samples proved being successful in obtaining enriched fractions of low abundance organelles, such as Golgi apparatus and ER components, for biochemical and molecular studies, and suitable for proteomic research, which makes it a useful tool for future studies of this and other mammalian cell lines.
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