Relationship between Severity of Lumbar Spinal Stenosis and Ligamentum Flavum Hypertrophy and Serum Inflammatory Factors.

Objective: This study is aimed at investigating the correlation between lumbar spinal stenosis (LSS) severity, ligamentum flavum hypertrophy, and the upregulation of inflammatory markers. Methods: From March 2019 and May 2022, eighty-five inpatients with LSS were enlisted as the study's research group, while sixty-five patients hospitalized for lumbar intervertebral disc herniation over the same time period served as the study's control group. Moreover, mild, moderate, and severe subgroups of patients were created within the research population based on their LSS severity. The ligamentum flavum thickness and the positive expression rates of TNF-α, TGF-ß1, and IL-1α were compared between the study group and the control group. The levels of TNF-α, TGF-ß1, and IL-1α that were found to be positively expressed were compared between the mild, moderate, and severe groups. Patients with LSS had their ligamentum flavum thickness and their positive expression rates of TNF-α, TGF-ß1, and IL-1α analyzed using Spearman correlation analysis. We evaluated the diagnostic utility of the positive expression rates of IL-α1, TGF-ß1, and TNF-α and ligamentum flavum thickness in distinguishing the severity of LSS using a receiver operating characteristic (ROC) curve. Results: The rates of both lower limb pain (40.00%) and intermittent claudication (80.00%) in the LSS group were higher than those in the lumbar disc herniation group (15.38%, 12.31%), with statistical significance (P < 0.05). However, no substantial disparity was observed in left lower limb pain, right lower limb pain, low back pain, lower limb sensation, muscle strength, and reflex abnormalities between the two groups (P > 0.05). Positive expressions of TGF-ß1, TNF-α, and IL-1α and thicker ligamentum flavum were more prevalent in the LSS group than in the lumbar intervertebral disc herniation group. All indexes were significantly (P < 0.05) higher in the moderate stenosis group than in the severe stenosis group. Additionally, the thickness of the ligamentum flavum and the positive expression rates of TNF-α, TGF-ß1, and IL-1α were higher in the mild and moderate stenosis groups than in the severe stenosis group. The expression levels of TNF-α, TGF-ß1, and IL-1α were favorably linked with ligamentum flavum thickness (P < 0.05). ROC curve analysis showed that the thickness of ligamentum flavum, the expression of IL-1α, the expression of TGF-ß1, and the expression of TNF-α could effectively diagnose mild, moderate, and severe LSS (P < 0.05). Conclusion: Ligamentum flavum hypertrophy and positive expression rates of IL-1α, TGF-ß1, and TNF-α are closely linked to LSS, which can effectively identify mild, moderate, and severe LSS.

An AAV-based, room-temperature-stable, single-dose COVID-19 vaccine provides durable immunogenicity and protection in non-human primates.

The SARS-CoV-2 pandemic has affected more than 185 million people worldwide resulting in over 4 million deaths. To contain the pandemic, there is a continued need for safe vaccines that provide durable protection at low and scalable doses and can be deployed easily. Here, AAVCOVID-1, an adeno-associated viral (AAV), spike-gene-based vaccine candidate demonstrates potent immunogenicity in mouse and non-human primates following a single injection and confers complete protection from SARS-CoV-2 challenge in macaques. Peak neutralizing antibody titers are sustained at 1 year and complemented by functional memory T cell responses. The AAVCOVID vector has no relevant pre-existing immunity in humans and does not elicit cross-reactivity to common AAVs used in gene therapy. Vector genome persistence and expression wanes following injection. The single low-dose requirement, high-yield manufacturability, and 1-month stability for storage at room temperature may make this technology well suited to support effective immunization campaigns for emerging pathogens on a global scale.

An aptly industrialized bioprocess for lactic acid production from corn stover using thermotolerant microbial consortia.

Chemical pretreatment of lignocellulosic biomass is a critical step in the conversion of lignocellulose to biofuels and biochemical. The main drawback of this pretreatment process is the formation of inhibitors which exhibit combined toxicity to microorganisms and result to low product concentrations and yields. In this study, the selection of microbial consortia by enrichment on hydrolysate of H2SO4-pretreated corn stover (pre-CS) without detoxification has been investigated as an efficient way to develop new strategies for lignocellulose utilization. The analysis of cattle stomach-dervied microbial consortia domesticated to degrade hydrolysate of pre-CS to produce lactic acid (LA) at different temperatures was investigated. Bacterial 16S rRNA gene amplicon sequencing analyses indicated that the three microbial consortia were taxonomically distinct and Enterococcus became dominant at high temperature. The highest glucose consumption rate was observed at 45 °C, while the three microbial consortia showed similar consumption rates of xylose and arabinose. The selected microbial consortia DUT37, DUT45 and DUT47 showed preferable resistances to inhibitors in hydrolysate of pre-CS and abilities of xylose utilization. A batch simultaneous saccharification and fermentation (SSF) process was developed by microbial consortium DUT47 at 47 °C to produce LA from pre-CS under non-detoxified and non-sterile conditions. The LA concentration and yield were 43.73 g/L and 0.50 g/g-corn stover (CS), respectively. Microbial consortium DUT47 has been shown to be suitable for LA production from H2SO4-pretreated corn stover without detoxification due to its thermophilic growth characteristics, robust tolerance of inhibitors, and the simultaneous utilization of glucose and xylose.

Immunogenicity of an AAV-based, room-temperature stable, single dose COVID-19 vaccine in mice and non-human primates.

The SARS-CoV-2 pandemic has affected more than 70 million people worldwide and resulted in over 1.5 million deaths. A broad deployment of effective immunization campaigns to achieve population immunity at global scale will depend on the biological and logistical attributes of the vaccine. Here, two adeno-associated viral (AAV)-based vaccine candidates demonstrate potent immunogenicity in mouse and nonhuman primates following a single injection. Peak neutralizing antibody titers remain sustained at 5 months and are complemented by functional memory T-cells responses. The AAVrh32.33 capsid of the AAVCOVID vaccine is an engineered AAV to which no relevant pre-existing immunity exists in humans. Moreover, the vaccine is stable at room temperature for at least one month and is produced at high yields using established commercial manufacturing processes in the gene therapy industry. Thus, this methodology holds as a very promising single dose, thermostable vaccine platform well-suited to address emerging pathogens on a global scale.

Impact of virus-antibody interactions on viral clearance in anion exchange chromatography.

Viral clearance is an important performance metric for the downstream process of monoclonal antibodies (mAbs) due to its impact on patient safety. Anion exchange chromatography (AEX) has been well-accepted in the industry as one of the workhorse techniques for removing viruses, and is considered to be able to achieve high log clearance values under most operating conditions. However, it is not uncommon for viral clearance results on AEX to fall below the desired level despite operating under conditions that should achieve high clearance levels according to conventional wisdom of how this mode of chromatography operates. In this study, a design of experiment (DoE) approach was used to develop a more fundamental understanding of viral clearance during AEX chromatography using Minute Virus of Mice (MVM) on POROS HQ resin. Load pH, conductivity and virus concentration were evaluated as design factors for three mAbs with varying physical and chemical properties. The hydrophobicity and surface charge distributions of the molecules were found to be the most significant factors in influencing viral clearance performance, and the viral clearance trends did not seem to fit with conventional wisdom. To explain this seemingly unconventional behavior, we propose a new mechanism that suggests that interactions between the mAb and the virus have a major contribution on retention of the virus on the resin. This furthered understanding may help improve the predictability, performance and robustness of viral clearance during AEX chromatography.

Simultaneous liquefaction, saccharification, and fermentation of L-lactic acid using aging paddy rice with hull by an isolated thermotolerant Enterococcus faecalis DUT1805.

Simultaneous liquefaction, saccharification, and fermentation (SLSF) has attracted much attention for the production of bio-based chemicals, including L-lactic acid, due to its high efficiency and low cost. In this study, a lactic acid-producing bacterium with high tolerance of temperature up to 55 °C was isolated and characterized as Enterococcus faecalis DUT1805. Various strategies of stepwise controlled temperature were proposed and investigated for glucose utilization. The results indicated that E. faecalis DUT 1805 exhibited an optimal temperature at 50 °C, which could achieve temperature compatibility of enzyme, saccharification, and fermentation, and decrease the possibility of contamination by the other microorganisms during the large-scale fermentation. To reduce the cost of raw material and operation for lactic acid production, aging paddy rice with hull (APRH) was used in L-lactic acid production by simultaneous liquefaction, saccharification, and fermentation (SLSF). An open SLSF operation at 50 °C and pH 6.5, and 17% (w/v) solid loading in 5 L bioreactors was demonstrated with the lactic acid titer, yield, and productivity of 73.75 g/L, 87% to initial starch, and 2.17 g/(L h), respectively.

Understanding the Effect of Atomic-Scale Surface Migration of Bridging Ions in Binding Li3PO4 to the Surface of Spinel Cathode Materials.

Spinel cathode materials (e.g., LiMn2O4 and LiNi0.5Mn1.5O4) with strongly bonded surface coatings are desirable for delivering improved electrochemical performance in long-term cycling. Here, we report that the introduction of bridging ions such as Fe and Co, which can diffuse into both the spinel cathode materials and Li3PO4, the latter is found to cover the spinel surface in the form of dense and uniform particles (∼2-3 nm). Detailed structural analysis of the surface reveals that the bridging ions diffuse into the 16c site of the spinel structure to form ion-doped spinel cathode materials, which contribute to the formation of strong bonds between the surface and Li3PO4, possibly via spinel-(surface bridging ions)-Li3PO4 bonds. The critical role of the surface bridging ions is further investigated by heating the as-formed Li3PO4-coated spinel cathode materials (with bridging ions) to high temperatures, resulting in further diffusion of bringing ions from the surface to the interior of the spinel materials and consequently depletion of the surface spinel-(surface bridging ions)-Li3PO4 bonds. This leads to the gradual growth of surface Li3PO4 particles (∼20 nm) and the exposure of the spinel surface.

A structural model for glutathione-complexed iron-sulfur cluster as a substrate for ABCB7-type transporters.

Glutathione-complexed [2Fe-2S] cluster is shown to significantly stimulate the ATPase activity of an ABCB7-type transporter in both solution and proteoliposome-bound forms (KD ∼ 68 µM). The cluster is a likely natural substrate for this transporter, which has been implicated in cytosolic Fe-S cluster protein maturation. A possible substrate-binding site is identified on a new structural model for the active transporter.

Glutathione-complexed iron-sulfur clusters. Reaction intermediates and evidence for a template effect promoting assembly and stability.

Assembly and stabilization of a glutathione-complexed [2Fe-2S] cluster is promoted by aggregation of glutathione. The cluster core selects the tetramer species from a collection of equilibrating solution aggregate species, and in turn the core is stabilized toward hydrolytic degradation. Studies of glutathione derivatives, in combination with mass spectrometric and Mössbauer investigations provide insight on reaction intermediates during formation of [2Fe-2S](GS)4(2-).

Human ferredoxin-2 displays a unique conformational change.

Human ferredoxin-1 (hFd1) and human ferredoxin-2 (hFd2) share high sequence similarity but serve on distinct cellular pathways. A unique conformational change is observed when holo hFd2 is warmed to physiological temperatures, or higher. Enzymatic studies show that this conformational change causes the increase of affinity between hFd2 and adrenodoxin reductase. No such change was observed for hFd1, which may contribute to the distinct cellular functions of hFd1 and hFd2 under physiological conditions.

Glutathione complexed Fe-S centers.

Glutathione (γ-glutamyl-cysteinyl-glycine, GSH) is a major thiol-containing peptide with cellular levels of up to 10 mM. (1) Several recent reports have demonstrated glutaredoxins (Grx) to form [Fe(2)S(2)] cluster-bridged dimers, where glutathione provides two exogenous thiol ligands, and have implicated such species in cellular iron sulfur cluster biosynthesis. We report the finding that glutathione alone can coordinate and stabilize an [Fe(2)S(2)] cluster under physiological conditions, with optical, redox, Mössbauer, and NMR characteristics that are consistent with a [Fe(2)S(2)](GS)(4) composition. The Fe-S assembly protein ISU catalyzes formation of [Fe(2)S(2)](GS)(4) from iron and sulfide ions in the presence of glutathione, and the [Fe(2)S(2)] core undergoes reversible exchange between apo ISU and free glutathione.

Structural, Mechanistic and Coordination Chemistry of Relevance to the Biosynthesis of Iron-Sulfur and Related Iron Cofactors.

Iron-sulfur clusters are an important class of protein-bound prosthetic center that find wide utility in nature. Roles include electron transfer, enzyme catalysis, protein structure stabilization, and regulation of gene expression as transcriptional and translational sensors. In eukaryotes their biosynthesis requires a complex molecular machinery that is located within the mitochondrion, while bacteria exhibit up to three independent cluster assembly pathways. All of these paths share common themes. This review summarizes some key structural and functional properties of three central proteins dedicated to the Fe-S cluster assembly process: namely, the sulfide donor (cysteine desulfurase); iron donor (frataxin), and the iron-sulfur cluster scaffold protein (IscU/ISU).

Mechanism of glutaredoxin-ISU [2Fe-2S] cluster exchange.

Exchange of [2Fe-2S] centers between Grx2 and the cluster scaffold protein ISU, and characterization of two mutually exclusive Grx2 binding sites on ISU by isothermal titration calorimetry supports a direct link for Grx and glutathione involvement in ISU promoted Fe-S cluster biosynthesis.

A structural and functional homolog supports a general role for frataxin in cellular iron chemistry.

Bacillus subtilis YdhG lacks sequence homology, but demonstrates structural and functional similarity to the frataxin family, supporting a general cellular role for frataxin-type proteins in cellular iron homeostasis.

Iron-sulfur cluster biosynthesis: functional characterization of the N- and C-terminal domains of human NFU.

Human NFU (also known as HIRIP5) has been implicated in cellular iron-sulfur cluster biosynthesis. Bacterial and yeast forms are smaller than the human protein and are homologous to the C-terminal domain of the latter. This C-terminal domain contains a pair of redox active cysteines and demonstrates thioredoxin-like activity by mediating persulfide bond cleavage of sulfur-loaded NifS (an IscS-type protein), the sulfide donor for [2Fe-2S] cluster assembly on ISU-type scaffold proteins. Herein, the affinity of full-length human NFU and the individual N- and C-terminal domains for sulfide donor and cluster scaffold proteins is assessed. The influence of the N-terminal domain on C-terminal NFU binding to NifS and persulfide reductase activity is also examined. Only the C-terminal domain is required for persulfide reductase activity, while complex formation of NifS with full-length NFU is similar to that of the C-terminal domain alone (K(D) approximately 9.7 +/- 0.7 and 10.1 +/- 0.6 microM, respectively). There is negligible affinity between the isolated C- and N-terminal domains, while the N-terminal domain has negligible affinity for either sulfide donor or cluster scaffold proteins. The temperature dependence of the binding enthalpy for formation of the complex between NifS and the C-terminal domain of NFU yields a change in molar heat capacity (DeltaC(p) approximately 138 cal mol(-1) K(-1)) that suggests bonding at the protein-protein interface is dominated by electrostatic interactions. This is consistent with electrostatic potential maps for bacterial homologues of the N- and C-terminal domains of human NFU, which most likely reflect the structural characteristics expected for full-length human NFU.