7141 research outputs found
Sort by
Comparing Experiences of Constitutional Reforms to Enshrine the Right to Water in Brazil, Colombia, and Peru: Opportunities and Limitations
Get PDFIn this paper we compare recent efforts towards the constitutionalization of the right to water in Brazil, Colombia, and Peru to understand the opportunities and limitations related to the attempts to enhance access to piped water to the highest normative level. Peru passed a constitutional amendment in 2017 while Brazil and Colombia have seen much right-to-water activism but have not succeeded in passing such reforms. We explore the role of the existing domestic legal frameworks on drinkable water provision and water management towards the approval of constitutional amendments. We find that all three countries have specialized laws, water governing institutions, and constitutional jurisprudence connecting access to water with rights, but the legal opportunity structures to enforce socio-economic rights vary; they are stronger in Colombia and Brazil, and weaker in Peru. We argue that legal opportunity structures build legal environments that influence constitutional reform success. Legal opportunity structures act as incentives both for social movements to push for reforms and for actors with legislative power to accept or reject them. Our findings also show that in some contexts political cost is a key element of constitutional reforms that enshrine the right to water; therefore, this is an element that should be considered when analyzing these processes
Isolation and Characterization of Exoenzyme Over-Producing GFP-Tagged Mutant of Soft Rot Pathogen, Pectobacterium versatile
No full textSoft rot pathogens produce plant cell wall degrading enzymes (PCWDEs) as a major virulence factor. Mutants that over-produce the enzymes are hyper-virulent while enzyme-deficient mutants are non-virulent. The main objective of this research was to isolate and characterize pleiotropic mutants of Pectobacterium versatile and identify the mutated genes and their role in regulation of virulence. We constructed a stable, independent, and saturated GFP-tagged mutant library of Pectobacterium versatile by the process of mini-Tn5 transposon insertion mutagenesis with the conditional Pir-dependent R6K-based suicide vector. We screened for and isolated mutants that were over-producing extracellular protease (Prt). Quantitative, and semi-quantitative enzyme assays revealed the increased production of other extracellular enzymes such as- cellulase, polygalacturonase and pectate-lyase. The mutants and parental strains were inoculated on celery petioles, potato tubers and carrot root discs for pathogenicity test. The hyper virulent mutants macerated more host tissues than the parental strain. The mutant gene was identified using the modified protocol for direct Sanger sequencing of mutant genomes. We found that the mutants had transposon insertion in several previously known regulatory genes such as rsmA and rsmC, and unknown ones such as degQ. The cosmid clone of degQ obtained through the PCR screening of Ecc71 genomic library, complemented the mutant phenotype. An understanding of the role of these genes in the disease process can be used in designing effective management strategies for soft rot disease
The Cytotoxic Activity of Thymus vulgaris Extract on Cancer Cell Lines, and Antimicrobial Activity on Strains of Pathogenic Bacteria
No full textMedicinal plants and their phytochemicals have been used in the treatment of different diseases since antiquity. Extensive research into medicinal plants has shown that there is a significant influence for plant compounds in treating severe and chronic diseases that cause of death across the globe. Moreover, herbal plants prove to be an efficient way to treat different cancerous infections, and they have shown antimicrobial properties. In the present study, Thymus Vulgaris extract has been tested for cytotoxicity activity against Bt20 (breast cancer cell line) and PC3 (prostate cancer cell lines) for 24 hours, and for antibacterial activity against different strains of bacteria (Salmonella enterica, Escherichia coli, Staphylococcus aureus, and Bacillus cereus). This study hypothesized that Thymus Vulgaris extract has anticancer activity and has a tremendous antimicrobial effect on these bacteria strains. In cancer cell lines, a cell viability indicator Alamar blue reagent and a fluorescent plate reader were used to determine the cell viability. In bacteria, the growth of bacteria was determined by monitoring the increase around the thyme extract. This study showed that the section of Thymus vulgaris had shown inhibition in the growth activity of BT20 (breast cancer cell lines) at the three highest concentrations (1.384, 2.768, and 5.536 μg/ml). Thymus vulgaris extract at concentrations of 1.384, 2.768, and 5.536 μg/ml significantly inhibited PC3 cell viability. Thyme was most potent against BT-20 cell line, whereas it was the least effective against PC-3. Thymus vulgaris extract has antibacterial activities against bacteria. At the two highest concentrations (5.536 and 1.384 μg/ml), Thymus vulgaris extract inhibited the growth of bacteria (Salmonella enterica, Escherichia coli, Staphylococcus aureus, and Bacillus cereus); whereas at concentrations (0.346 and 0.0865 μg/ml), Thymus vulgaris extract showed slight antibacterial activities only against Bacillus cereus and Staphylococcus aureus. These findings highlight that Thymus vulgaris extract has anticancer and antibacterial activity, and this study supports our hypothesis. These studies show that the Thymus vulgaris has potential for use as anticancer and antimicrobial activity. Further research in the latter two studies is under consideration
A Case Study of the Factors that Influence Male Saudi Students’ Participation in University Classrooms in the United States
No full textSince the 1940’s, the United States has opened its doors for international students to study and gain knowledge and skills within its borders. However, there are considerable concerns about the integration of these international students and their participation in the classroom. Most international students hail from different cultural and social backgrounds and they are often met with challenges that impede their academic performance and participation in class. It is against this backdrop that this study explores factors that influence undergraduate male Saudi students\u27 participation in American university classrooms by examining their perceptions of classroom participation. This study employs a qualitative case study approach with multiple participants to address the research questions. Participants included eight undergraduate Saudi students at a single HBCU in the southern U.S. Data collection techniques included individual interviews, a focus group interview, and artifacts. The results show that language barriers, cultural differences, teaching methods, background knowledge, social context, personality, and other factors, such as interest in the subject, significantly influence student participation in the classroom
An Examination of Opportunities and Constraints of Marketing Local Foods in Tennessee
No full textIn recent years, the demand for food produced in the same locality it is distributed has increased. The major driving factor is the increase in consumer demand for food with better quality. Consumer’ preference for less processed food naturally creates an opportunity to produce and market high-quality food to satisfy demand. The logistics breakdown in the agricultural sector during the COVID-19 pandemic and food shortage shows that researchers have widely neglected adequate and comprehensive research on the local food marketing system. The purpose of the study is to evaluate the performance of existing farm-to-consumer marketing efforts, better understand the potential expansion of the market, and identify barriers preventing producers from utilizing existing marketing channels. Primary data (Direct information from producers) was collected to test the assumption that there are marketing opportunities for local food in Tennessee. The research analyzed primary data collected from local food producers via an online survey to examine the options found in the production and marketing of local food in Tennessee. The focus was on marketing local food directly to consumers and retailers through various marketing channels. The research considered the factors (challenges and opportunities) that encourage or discourage producers in the marketing of local foods. There were 56 actual respondents between April and August 2021 to the survey. The analyzed collected data demonstrated factors that affect the choice of selected marketing channels by producers. The results of the statistical analysis of nine marketing channels in the study demonstrated how the demographical variables (age, education, etc.) impact the choice of each marketing channel. One or more of a farmer\u27s demographical variables significantly impact tested markets. The two most impacted markets are the farmers\u27 market and the direct-2-restaurant market. The most significant challenge that farmers encounter is the impact of the covid-19 pandemic and a lack of funds to either start a new business or expand an existing business. The most significant opportunity in marketing local food in Tennessee is the increasing demand for local food.Improved understanding of Tennessee\u27s local food marketing system will continually help local food producers increase production efficiencies with better marketing strategies
Biophysical Studies of the Effects of Antimicrobial and Cell Penetrating Peptides on Vesicles Mimicking Bacterial and Mammalian Membranes
No full textDrug-resistant bacteria remains a challenge in infectious diseases, and the need for the development of new antimicrobial agents cannot be overstated. Antimicrobial peptides (AMPs) from innate immunity of animals are among the most interesting candidates for this role, due to their efficacy against pathogens and their likelihood to not induce drug resistance. However, their physical properties present challenges in the creation of biologically stable agents and in balancing antimicrobial efficacy against host cell membrane toxicity, and their killing mechanism is still open to debate. On the other hand, the prevalence of neurodegenerative diseases in USA and high-income countries is devastating the healthcare system. There is a need for drug delivery systems. Cell penetrating peptides (CPPs) are considered as potential drug delivery vectors, because they are able to cross the cell membrane either by themselves or together with a molecule cargo. Nevertheless, their entry mechanism into cell is still unclear.These two families of peptides are a possible answer to the treatment of drug-resistant bacteria and the exploration of drug delivery systems. The objective of this project is to carry out a detailed analysis of the interaction between selected AMPs and CPPs and vesicles mimicking bacterial and mammalian membranes using biophysical techniques. AMPs composed of RW units seem to be very powerful against pathogens. We hypothesize that increasing the net positive charge and the hydrophobic moment will improve their affinity for bacterial membranes and moderate their toxicity. We also hypothesize that the use of advanced model membranes will provide new insights into the mechanism of entry of CPPs and AMPs into the cells. We used spectroscopic techniques as well as biological assays measuring the minimum inhibitory concentration (MIC) values for AMPs. Some AMPs have shown ultralow MIC values against some WHO top priority pathogens. Overall, this project has presented (1) a sequence template composed of (RW)n units that can be used to design potential alternatives for conventional antimicrobial agents and (2) the threshold concentrations that trigger direct translocation of the CPPs Pep-1 and penetratin. The techniques employed here can be used in a complementary way to study peptide-lipid interactions
Elevated atmospheric CO2 concentration triggers redistribution of nitrogen to promote tillering in rice
Get PDFElevated atmospheric CO2 concentration (eCO2) often reduces nitrogen (N) content in rice plants and stimulates tillering. However, there is a general consensus that reduced N would constrain rice tillering. To resolve this contradiction, we investigated N distribution and transcriptomic changes in different rice plant organs after subjecting them to eCO2 and different N application rates. Our results showed that eCO2 significantly promoted rice tillers (by 0.6, 1.1, 1.7, and 2.1 tillers/plant at 0, 75, 150, and 225 kg N ha−1 N application rates, respectively) and more tillers were produced under higher N application rates, confirming that N availability constrained tillering in the early stages of growth. Although N content declined in the leaves (−11.0 to −20.7 mg g−1) and sheaths (−9.8 to −28.8 mg g−1) of rice plants exposed to eCO2, the N content of newly emerged tillers on plants exposed to eCO2 equaled or exceeded the N content of tillers produced under ambient CO2 conditions. Apparently, the redistribution of N within the plant per se was a critical adaptation strategy to the eCO2 condition. Transcriptomic analysis revealed that eCO2 induced less extensive alteration of gene expression than did N application. Most importantly, the expression levels of multiple N-related transporters and receptors such as nitrate transporter NRT2.3a/b and NRT1.1a/b were differentially regulated in leaf and shoot apical meristem, suggesting that multiple genes were involved in sensing the N signal and transporting N metabolites to adapt to eCO2. The redistribution of N in different organs could be a universal adaptation strategy of terrestrial plants to eCO2
