186 research outputs found
Sialic Acid Receptors: The Key to Solving the Enigma of Zoonotic Virus Spillover
No full textEmerging viral diseases are a major threat to global health, and nearly two-thirds of emerging human infectious diseases are zoonotic. Most of the human epidemics and pandemics were caused by the spillover of viruses from wild mammals. Viruses that infect humans and a wide range of animals have historically caused devastating epidemics and pandemics. An in-depth understanding of the mechanisms of viral emergence and zoonotic spillover is still lacking. Receptors are major determinants of host susceptibility to viruses. Animal species sharing host cell receptors that support the binding of multiple viruses can play a key role in virus spillover and the emergence of novel viruses and their variants. Sialic acids (SAs), which are linked to glycoproteins and ganglioside serve as receptors for several human and animal viruses. In particular, influenza and coronaviruses, which represent two of the most important zoonotic threats, use SAs as cellular entry receptors. This is a comprehensive review of our current knowledge of SA receptor distribution among animal species and the range of viruses that use SAs as receptors. SA receptor tropism and the predicted natural susceptibility to viruses can inform targeted surveillance of domestic and wild animals to prevent the future emergence of zoonotic viruses.This article is published as Kuchipudi, Suresh V., Rahul K. Nelli, Abhinay Gontu, Rashmi Satyakumar, Meera Surendran Nair, and Murugan Subbiah. "Sialic acid receptors: the key to solving the enigma of zoonotic virus spillover." Viruses 13, no. 2 (2021): 262. doi: https://doi.org/10.3390/v13020262
Factors involved in the proliferation of blaCMY-2 plasmid-bearing Escherichia coli in cattle
No full textThesis (Ph.D.), College of Veterinary Medicine, Washington State UniversityThird-generation cephalosporins are a crucial component of the antibiotic arsenal for human and veterinary medicine. Resistance to third-generation cephalosporins is often conveyed by blaCMY-2 plasmids. The prevalence of blaCMY-2 plasmid-bearing Salmonella and Escherichia coli and ceftiofur (third-generation cephalosporin) use in livestock has been implicated in this process. Nevertheless, injection of ceftiofur results in limited effect on the enteric flora and the majority of drug excreted in the urine. We employed a series of in vitro and in vivo passage studies showing that blaCMY-2 plasmids impose a fitness cost on their bacterial host and this cost is not mitigated by conjugation or segregation systems (Chapter I). Thus, selection is required to maintain blaCMY-2 plasmids in a population. After administration to cattle ceftiofur is quickly converted in to pharmacologically active ceftiofur metabolite (CFM). Because most (~ 70%) CFM is excreted through urine, we hypothesized that selection for cefR E. coli occurs primarily ex vivo rather than in vivo. We first found that when mixed in soil ceftiofur remains bioavailable but some antibiotics (e.g. tetracycline) are not (Chapter II). To further evaluate the fate of CFM ex vivo, we used matrices consisting of soil and feces with urine containing CFM and examined the factors that impact the longevity of CFM. Our findings showed that CFM remains bioavailable in soil for a longer period with higher concentration (as expected) and at colder temperatures. CFM bioavailability is retained much longer in autoclaved soil indicating that the soil microflora is probably responsible for eventual degradation of CFM. Importantly, our findings show that CFM confers a significant numerical (1 to 1.5 log10 cfu per g matrix at 23°C) advantage to ceftiofur resistant bacteria in the soil and this advantage maintained well-beyond the period of CFM bioavailability; exposure to CFM extends survivorship of cefR E. coli an estimated 80 days compared to non-exposed populations. We also showed that exposing dairy calves to bedding with blaCMY-2 positive E. coli is sufficient for transmission (Chapter III). Consequently, the numerical advantage conferred by exposure to CFM in soil is likely to increase the likelihood transmitting cefR E. coli back to livestock.Department of Veterinary Microbiology and Pathology, Washington State Universit
Author Correction: COVID-19 vaccine guidance for patients with cancer participating in oncology clinical trials
No full textIn the original version of this Perspective, the name of the author Giuseppe Curigliano was incorrectly written as Guiseppe Curigiliano. The affiliations have been corrected in the HTML and PDF versions of the manuscrip
Polymeric design of cell culture materials that guide the differentiation of human pluripotent stem cells
No full textHuman pluripotent stem cells (hPSCs), including embryonic stem cells (hESCs) and induced pluripotent stem cells (hiPSCs), have the potential to differentiate into many cell types that originate from the three germ layers, such as dopamine-secreting cells and insulin-secreting cells for the treatment of Alzheimer's disease and diabetes, respectively. However, it is challenging to guide hPSC differentiation into desired cell lineages due to their varying differentiation ability. A reasonable strategy is to mimic the stem cell microenvironment for the differentiation of hPSCs into specific cell lineages using optimal polymeric biomaterials for hPSC culture. This review summarizes various methods for differentiating hPSCs cultured on polymeric biomaterials and discusses the optimal methods and cell culture polymeric biomaterials for hPSC differentiation into specific cell lineages. The recent trend in protocols avoids embryoid body (EB, aggregated cells) formation because EBs contain different types of cells. The combination of appropriate differentiation protocols and cell culture polymeric biomaterials for the differentiation of hPSCs into specific cell lineages will produce a large quantity of highly pure GMP-grade differentiated cells for use in translational medicine
Author Correction: EGFR and HER2 exon 20 insertions in solid tumours: from biology to treatment (Nature Reviews Clinical Oncology, (2022), 19, 1, (51-69), 10.1038/s41571-021-00558-1)
No full textRainfall changes over tropical montane cloud forests of southern Western Ghats, India
No full textCitation: Murugan, M., Shetty, P., Anandhi, A., Vasudevan, M., & Gopalan, S. (2009). Rainfall changes over tropical montane cloud forests of southern Western Ghats. Current Science, 97(12), 1755-1760.The southern Western Ghats tropical montane cloud forest sites (Gavi, Periyar, High wavys and Venniyar), which are characterized by frequent or seasonal cloud cover at the vegetation level, are considered one of the most threatened ecosystems in India and the world. Three out of four montane cloud forest sites studied in the southern Western Ghat had experienced diminishing trends of seasonal average and total rainfall, especially during summer monsoon season. The highest level of reduction for summer monsoon season was observed at Gavi rainforest station (>20 mm/14 years) in Kerala followed by Venniyar (>20 mm/20 years) site in Tamil Nadu. Average annual and total precipitation increased during the study period irrespective of the seasons over Periyar area, and the greatest values were recorded for season 2 (>25 mm/28 years). Positive trends for winter monsoon rainfall has been observed for three stations (Periyar, High wavys and Venniyar) except Gavi, and the trend was positive and significant (90%) for Periyar and High wavys. Increase in summer monsoon rainfall was observed for Periyar site and the trend was found to be significant (95%)
Novel Simulator for Wireline Mini-Fracture Testing
No full textWireline Mini-Fracture testing jobs consist of a short duration, small volume fracturing operation inside an open-hole borehole, where a certain amount of fluid is injected into the formation at constant rate using a Wireline Modular conveyed tool as a source of hydraulic power to pressurize the wellbore. The tool is configured with an inflatable straddle packer and an internal pump, which inflate/deflates the packers and supplies pressure to the formation until a hydraulic fracture is induced. This procedure is used to determine in–situ formation breakdown and closure pressure also known as minimum horizontal closure pressure. This provides vital information regarding hydraulic fracture design, water and gas injection management, fault re-activation, wellbore stability, sand production, rock mechanical properties, casing string design, cap and base rock integrity and gas storage design. Geomechanical and operational parameters such as, elastic properties, poro-elasticity, rock strength, formation pore pressure, far field horizontal stress, permeability/porosity distributions, borehole fluid properties among others, influences the performance of the Mini-Frac Jobs. In many cases poor understanding of the reservoir response to the fracture process, caused that the hydraulic fracture did not propagate deep into the formation. In other cases the pressure applied to the formation might be insufficient to break down the formation, leading to unsatisfactory application of the Mini-Fracture technique in the process. The objective of this thesis is to develop a Mini-Facture application simulator that uses the geomechanical and operational parameters that control the performance of a Mini-Fracture job and estimate the possibility of the occurrence of a tensile failure in the formation. The simulator is then validated by comparing its output with the results of stress test done in the field. With this simulator petrotechnical professionals and field engineers will have a platform that simulates the pressure responses and fracture initialization during Mini-Frac treatments, incorporating all the variables affecting a Wireline Mini-Fracture job, helping the design engineer to make key decisions about the ultimate or required fracture plan. Furthermore the simulator will reduce the uncertainties that limit the reliability of the Wireline Mini-Fracture treatment by allowing the selection of appropriate tool configuration based on the job objectives and the geological environmental conditions. Finally this project demonstrates that combining the appropriate constitutive relations that reflect the coupling among the tool operational performance with wellbore flow, reservoir and geomechanics modelling a Mini-Fracture simulator can be developed.Petroleum EngineeringGeoscience & EngineeringCivil Engineering and Geoscience
Synthesis and Preliminary Investigation of Metal Nanoparticles from the Stem Extract of Bacopa sp. for the Treatment of Lung Cancer
No full textLung cancer is the third most common cancer in women and the most common cancer in males. Chemotherapy, allopathy, hormone therapy, radiation therapy, surgery, immune system, and targeted therapies are frequently used to treat lung cancer. These medications induce other diseases and have a variety of negative effects. Thus, we used a different strategy and sought to treat lung cancer with medicinal herbs. We selected the perennial creeping herb Bacopa monnieri, which belongs to the Scrophulariaceae family, among other medicinal herbs. It contains several active phytoconstituents, including sterols, alkaloids, flavanoids, terpenoids, and saponins. The primary component with anti-lung cancer efficacy is phytosterol, according to the components. According to the phytochemical investigation, this plant contained it. The literature review indicates that the problem is lessened by nanoparticle production. Thus, the novelty of our work is the manufacture of zinc oxide nanoparticles for the treatment of lung cancer using BM stem extracts. Researchers have been interested in ZnO material because of its huge band gap (3.37 eV) with n-type semi-conductivity and high excitonic binding energy (60 meV) with regards to the different semiconductor nanomaterials, such as TiO2, SnO2, GaN, CuO, GaAs, Si, and ZnO. Zinc oxide in bulk is economical and can be used for many different industrial processes, such as the creation of nanoparticles. Zinc acetate serves as the precursor and stem extract serves as the reducing agent in the synthesis. The absorbance peak between 300 and 400 nm in UV spectroscopy was used to characterize the ZnO nanoparticles that were produced from hydromethanolic BM stem extract. In later research, lung cancer treatment might be considered. Given that lung (A549) cell lines will be treated with phytosterol-containing hydromethanolic BM stem extract in the form of ZnO nanoparticles, which will cause cell death by reducing cell proliferation, DNA damage and apoptosis may occur
Reducing indicator organism E.coli in drinking water using Chitosan nano coated pot system: An inexpensive technique
No full textIn this study the drinking water is treated by nano coated pottery was produced by using chitosan nano particles prepared from marine crab shells. It is an alternative method for physical and chemical water treatment. In this experiment the low cost, non toxic and pollution free chitosan nano particles was prepared in laboratory level then it was integrated into existing traditional water storage pot system and through which indicator organism E.coli number was reduced effectively. The presence of nano sized particles in the prepared samples and capacity of integration and elution of nano particles in the pot systems were determined by XRD and AFMN and N2 compound elementary analysis method respectively. The result from this experiment showed that compared with control pot system the chitosan coated pot has more potential for reducing indicator microorganisms E.coli in the water sample. Also, it was concluded that this low cost and pollution free technology is suitable for purification of contaminated water sample in rural as well as urban areas. However it has some limitations that will be overcome by further research. </jats:p
- …
