Preparation of electrospun polycaprolactone nanofiber mats loaded with microalgal extracts

Sustainable, ecological, and biocompatible materials are emerging for the development of novel components for tissue engineering. Microalgae being one of the unique organisms on Earth to provide various novel compounds with certain bioactivities are also a good source for the development of novel tissue scaffold materials. In this study, electrospinning technique was utilized to fabricate nanofibers from polycaprolactone loaded with microalgal extracts obtained from Haematococcus pluvialis (vegetative and carotenoid producing form) and Chlorella vulgaris. The FTIR results showed that, blending microalgae with polycaprolactone give unique bands rooted from microalgae and polycaprolactone structure. The samples were not diversified from each other, however stable bands were observed. SEM analysis revealed a uniform fiber fabrication with an average diameter of 810 ± 55 nm independent from microalgal extracts. MTT assay was done on HUVEC cell lines and results showed that nanofiber mats helped cell proliferation with extended time. Biodegradation resulted with mineral accumulation on the surface of same samples however the fiber degradation was uniform. With slow but stable biodegradation characteristics, microalgal extract loaded nanofiber mats holds great potential to be novel tissue scaffold material.     

Multiplex Conditional Mutagenesis Using Transgenic Expression of Cas9 and sgRNAs

Determining the mechanism of gene function is greatly enhanced using conditional mutagenesis. However, generating engineered conditional alleles is inefficient and has only been widely used in mice. Importantly, multiplex conditional mutagenesis requires extensive breeding. Here we demonstrate a system for one-generation multiplex conditional mutagenesis in zebrafish (Danio rerio) using transgenic expression of both cas9 and multiple single guide RNAs (sgRNAs). We describe five distinct zebrafish U6 promoters for sgRNA expression and demonstrate efficient multiplex biallelic inactivation of tyrosinase and insulin receptor a and b, resulting in defects in pigmentation and glucose homeostasis. Furthermore, we demonstrate temporal and tissue-specific mutagenesis using transgenic expression of Cas9. Heat-shock-inducible expression of cas9 allows temporal control of tyr mutagenesis. Liver-specific expression of cas9 disrupts insulin receptor a and b, causing fasting hypoglycemia and postprandial hyperglycemia. We also show that delivery of sgRNAs targeting ascl1a into the eye leads to impaired damage-induced photoreceptor regeneration. Our findings suggest that CRISPR/Cas9-based conditional mutagenesis in zebrafish is not only feasible but rapid and straightforward.     

Crystal structures and fragment screening of SARS-CoV-2 NSP14 reveal details of exoribonuclease activation and mRNA capping and provide starting points for antiviral drug development

NSP14 is a dual function enzyme containing an N-terminal exonuclease domain (ExoN) and C-terminal Guanine-N7-methyltransferase (N7-MTase) domain. Both activities are essential for the viral life cycle and may be targeted for anti-viral therapeutics. NSP14 forms a complex with NSP10, and this interaction enhances the nuclease but not the methyltransferase activity. We have determined the structure of SARS-CoV-2 NSP14 in the absence of NSP10 to 1.7 Å resolution. Comparisons with NSP14/NSP10 complexes reveal significant conformational changes that occur within the NSP14 ExoN domain upon binding of NSP10, including helix to coil transitions that facilitate the formation of the ExoN active site and provide an explanation of the stimulation of nuclease activity by NSP10. We have determined the structure of NSP14 in complex with cap analogue ^7MeGpppG, and observe conformational changes within a SAM/SAH interacting loop that plays a key role in viral mRNA capping offering new insights into MTase activity. We perform an X-ray fragment screen on NSP14, revealing 72 hits bound to sites of inhibition in the ExoN and MTase domains. These fragments serve as excellent starting point tools for structure guided development of NSP14 inhibitors that may be used to treat COVID-19 and potentially other future viral threats.     

Fundamentals of estimating the net benefits of ecosystem preservation: the case of the Salton Sea

This article, both theoretical and methodological in nature, argues the potential merits of using a net benefits’ framework as a tool to aid policy makers in their efforts to compare Salton Sea restoration alternatives and inform the public as to the potential magnitude and distribution of trade-offs associated with each alternative. A net benefits’ approach can provide a more accurate comparison and evaluation of the potential net returns from public spending on Salton Sea restoration than what would be provided under the suggested criteria of current legislative mandates. Furthermore, a net benefits’ framework provides a more lucid and systematic accounting framework by which to enumerate the full array of benefits and costs of each alternative for policy analysis. Finally, net benefits’ analysis serves to add transparency to the decision-making process so that the public gains an understanding of how its scarce resources, including both financial and natural capital, are being appropriated. Additionally, we illustrate and emphasize the importance of estimating the non-market values associated with many of the ecosystem services provided by the Salton Sea and describe the major techniques that do so. Guest editor: S. H. Hurlbert The Salton Sea Centennial Symposium. Proceedings of a Symposium Celebrating a Century of Symbiosis Among Agriculture, Wildlife and People, 1905–2005, held in San Diego, California, USA, March 2005     

Effect of taxifolin on cyclophosphamide-induced oxidative and inflammatory bladder injury in rats

The role of oxidative stress and inflammation in the pathogenesis of cyclophosphamide-related side effects has been demonstrated in previous studies. This study aimed to investigate the effect of taxifolin, due to its antioxidant and anti-inflammatory properties, on cyclophosphamide-induced oxidative and inflammatory bladder injury in albino Wistar rats. The taxifolin+cyclophosphamide (TCYC) group was given 50 mg/kg of taxifolin orally by gavage. Normal saline was used as a solvent for the cyclophosphamide (CYC) group and the healthy control (HC) group. One hour after taxifolin administration, 75 mg/kg of cyclophosphamide was intraperitoneally injected in the TCYC and CYC groups. This procedure was repeated once a day for 30 days. At the end of this period, biochemical markers were studied in the excised bladder tissues and histopathological evaluations were conducted. In the histopathological evaluation of the CYC group, severe epithelial irregularity, dilatation, congestion, and polymorphonuclear leukocyte accumulation in the vascular structures were observed. Additionally, the malondialdehyde (MDA), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) levels, the total oxidant status (TOS), and the oxidative stress index (OSI) values were significantly higher, and the total glutathione (tGSH) levels and total antioxidant status (TAS) were significantly lower in the CYC group in comparison to the HC group (P<0.001). Taxifolin reduced the cyclophosphamide-induced increases in the MDA, TNF-α, IL-1β, and IL-6 levels and the TOS and OSI values; it decreased the tGSH and TAS levels and reduced histopathological damage (P<0.001). Taxifolin may be useful in the treatment of cyclophosphamide-induced bladder damage.     

Beyond multiculturalism: interculturalism,diversity and urban governance

This review article discusses the volume by Giovanna Marconi and Elena Ostanel, eds. The Intercultural City: Migration, Minorities and the Management of Diversity, I.B. Tauris, 2016, in the larger context of studies on inclusion of migrants in cities. It evaluates the merits of interculturalism argument presented by the editors and contributing authors as it is applied to the migrants’ and refugees’ needs and demands from the city and public at large, and the transformation of identities of public spaces challenging assumptions of cultural uniformity at the national level. The issue of the viability of equitable and normatively justifiable governance of difference above and beyond multiculturalism is a very important one, especially so in an era where Deferred Action for Childhood Arrivals and expulsions of the Dreamers from the American cities have become part of our daily reality.