Optimization of Bacillus subtilis natto growth parameters in glycerol-based medium for vitamin K (Menaquinone-7) production in biofilm reactors

Bioprocess and Biosystems Engineering - Menaquinone-7 (MK-7) is the key form of vitamin K used as a dietary supplement and its production revolves around Bacillus subtilis natto. Current...     

Probiotics with ameliorating effects on the severity of skin inflammation in psoriasis: Evidence from experimental and clinical studies

Experimental and clinical studies have confirmed safety and the medical benefits of probiotics as immunomodulatory medications. Recent advances have emphasized the critical effect of gastrointestinal bacteria in the pathology of inflammatory disorders, even, outside the gut. Probiotics have shown promising results for curing skin-influencing inflammatory disorders through modulating the immune response by manipulating the gut microbiome. Psoriasis is a complex inflammatory skin disease, which exhibits a microbiome distinct from the normal skin. In the present review, we considered the impact of gastrointestinal microbiota on the psoriasis pathogenesis, and through literature survey, attempted to explore probiotic species utilized for psoriasis treatment.     

Caspase-3 is a component of Fas death-inducing signaling complex in lipid rafts and its activity is required for complete caspase-8 activation during Fas-mediated cell death

Since its discovery, caspase-8 has been placed at the apex of the proteolytic cascade triggered by death receptor (DR) cross-linking. Because of its capacity to interact with the cytoplasmic portion of DR, it has been suggested that caspase-8 acts independently of other caspases in the initiation of Fas and other DR signaling. In this study, we demonstrate that in Jurkat cells, caspase-3 cleavage is an early step during Fas-induced apoptosis. We show that caspase-3 processing into its p20 occurs rapidly after Fas cross-linking, in the absence of mitochondrial depolarization and caspase-9 activation. Moreover, caspase-3 is present in lipid rafts of untreated Jurkat cells and peripheral T lymphocytes. Caspase-3, caspase-8, and Fas-associated death domain are further recruited to lipid rafts of Jurkat cells following anti-Fas treatment. Fas immunoprecipitation reveals that caspase-3 is a component of the death-inducing signaling complex, suggesting that this cysteine protease is in close proximity to caspase-8. Furthermore, transduction of Jurkat cells with a caspase-3 dominant-negative form inhibits caspase-8 processing and results in inhibition of apoptosis, suggesting that caspase-3 activity is required for caspase-8 activation. Overall, these findings support a model whereby caspase-3 is a component of the death-inducing signaling complex located in lipid rafts, and as such, is involved in the amplification of caspase-8 activity by the mitochondrion.     

A preliminary biomechanical assessment of a polymer composite hip implant using an infrared thermography technique validated by strain gage measurements

With the resurgence of composite materials in orthopaedic applications, a rigorous assessment of stress is needed to predict any failure of bone-implant systems. For current biomechanics research, strain gage measurements are employed to experimentally validate finite element models, which then characterize stress in the bone and implant. Our preliminary study experimentally validates a relatively new nondestructive testing technique for orthopaedic implants. Lock-in infrared (IR) thermography validated with strain gage measurements was used to investigate the stress and strain patterns in a novel composite hip implant made of carbon fiber reinforced polyamide 12 (CF/PA12). The hip implant was instrumented with strain gages and mechanically tested using average axial cyclic forces of 840 N, 1500 N, and 2100 N with the implant at an adduction angle of 15 deg to simulate the single-legged stance phase of walking gait. Three-dimensional surface stress maps were also obtained using an IR thermography camera. Results showed almost perfect agreement of IR thermography versus strain gage data with a Pearson correlation of R(2) = 0.96 and a slope = 1.01 for the line of best fit. IR thermography detected hip implant peak stresses on the inferior-medial side just distal to the neck region of 31.14 MPa (at 840 N), 72.16 MPa (at 1500 N), and 119.86 MPa (at 2100 N). There was strong correlation between IR thermography-measured stresses and force application level at key locations on the implant along the medial (R(2) = 0.99) and lateral (R(2) = 0.83 to 0.99) surface, as well as at the peak stress point (R(2) = 0.81 to 0.97). This is the first study to experimentally validate and demonstrate the use of lock-in IR thermography to obtain three-dimensional stress fields of an orthopaedic device manufactured from a composite material.     

Primordial germ cell differentiation of nuclear transfer embryonic stem cells using surface modified electroconductive scaffolds

A combination of nanotopographical cues and surface modification of collagen and fibronectin is a potential platform in primordial germ cells (PGCs) differentiation. In the present study, the synergistic effect of nanotopography and surface modification on differentiation of nuclear transfer embryonic stem cells (nt-ESCs) toward PGC lineage was investigated. In order to achieve this goal, poly-anyline (PANi) was mix within poly-l-lactic acid (PLLA). Afterward, the random composite mats were fabricated using PLLA and PANi mix solution. The nanofiber topography notably upregulated the expressions of prdm14, mvh and c-kit compared with tissue culture polystyrene (TCP). Moreover, the combination of nanofiber topography and surface modification resulted in more enhancement of PGCs differentiation compared with non-modified nanofibrous scaffold. Additionally, gene expression results showed that mvh and c-kit were expressed at higher intensity in cells exposed to collagen and fibronectin rather than collagen or fibronectin solitary. These results demonstrated the importance of combined effect of collagen and fibronectin in order to develop a functional extracellular matrix (ECM) mimic in directing stem cell fate and the potential of such biofunctional scaffolds for treatment of infertility.     

The role of nitric oxide signaling in renoprotective effects of hydrogen sulfide against chronic kidney disease in rats: Involvement of oxidative stress,autophagy and apoptosis

The interplay between H₂S and nitric oxide (NO) is thought to contribute to renal functions. The current study was designed to assess the role of NO in mediating the renoprotective effects of hydrogen sulfide in the 5/6 nephrectomy (5/6 Nx) animal model. Forty rats were randomly assigned to 5 experimental groups: (a) Sham; (b) 5/6 Nx; (c) 5/6Nx+sodium hydrosulfide-a donor of H ₂S, (5/6Nx+sodium hydrosulfide [NaHS]); (d) 5/6Nx+NaHS+ L -NAME (a nonspecific nitric oxide synthase [NOS] inhibitor); (e) 5/6Nx+NaHS+aminoguanidine (a selective inhibitor of inducible NOS [iNOS]). Twelve weeks after 5/6 Nx, we assessed the expressions of iNOS and endothelial NOS (eNOS), oxidative/antioxidant status, renal fibrosis, urine N-acetyl-b-glucosaminidase (NAG) activity as the markers of kidney injury and various markers of apoptosis, inflammation, remodeling, and autophagy. NaHS treatment protected the animals against chronic kidney injury as depicted by improved oxidative/antioxidant status, reduced apoptosis, and autophagy and attenuated messenger RNA (mRNA) expression of genes associated with inflammation, remodeling, and NAG activity. Eight weeks Nω-nitro-l-arginine methyl ester ( L -NAME) administration reduced the protective effects of hydrogen sulfide. In contrast, aminoguanidine augmented the beneficial effects of hydrogen sulfide. Our finding revealed some fascinating interactions between NO and H ₂S in the kidney. Moreover, the study suggests that NO, in an isoform-dependent manner, can exert renoprotective effects in 5/6 Nx model of CKD.     

Accurate and rapid estimation of phosphene thresholds (REPT)

To calibrate the intensity of transcranial magnetic stimulation (TMS) at the occipital pole, the phosphene threshold is used as a measure of cortical excitability. The phosphene threshold (PT) refers to the intensity of magnetic stimulation that induces illusory flashes of light (phosphenes) on a proportion of trials. The existing PT estimation procedures lack the accuracy and mathematical rigour of modern threshold estimation methods. We present an improved and automatic procedure for estimating the PT which is based on the well-established Ψ Bayesian adaptive staircase approach. To validate the new procedure, we compared it with another commonly used procedure for estimating the PT. We found that our procedure is more accurate, reliable, and rapid when compared with an existing PT measurement procedure. The new procedure is implemented in Matlab and works automatically with the Magstim Rapid(2) stimulator using a convenient graphical user interface. The Matlab program is freely available for download.