Rapid toxicity assessment of six antifouling booster biocides using a microplate-based chlorophyll fluorescence in Undaria pinnatifida gametophytes

Biocides of antifouling agents can cause problems in marine ecosystems by damaging to non-target algal species. Aquatic bioassays are important means of assessing the quality of water containing mixtures of contaminants and of providing a safety standard for water management in an ecological context. In this study, a rapid, sensitive and inexpensive test method was developed using free-living male and female gametophytes of the brown macroalga Undaria pinnatifida. A conventional fluorometer was employed to evaluate the acute (48 h) toxic effects of six antifouling biocides: 4,5-Dichloro-2-octyl-isothiazolone (DCOIT), diuron, irgarol, medetomidine, tolylfluanid, zinc pyrithione (ZnPT). The decreasing toxicity in male and female gametophytes as estimated by EC50 (effective concentration at which 50% inhibition occurs) values was: diuron (0.037 and 0.128 mg l(-1), respectively) > irgarol (0.096 and 0.172 mg l(-1), respectively) > tolylfluanid (0.238 and 1.028 mg l(-1), respectively) > DCOIT (1.015 and 0.890 mg l(-1), respectively) > medetomidine (12.032 and 12.763 mg l(-1), respectively). For ZnPT, 50% fluorescence inhibition of U. pinnatifida gametophytes occurred at concentrations above 0.4 mg l(-1). The Undaria method is rapid, simple, practical, and cost-effective for the detection of photosynthesis-inhibiting biocides, thus making a useful tool for testing the toxicity of antifouling agents in marine environments

Voz, identidad y escucha: reflexiones de un refugiado

Para entender y responder mejor a las necesidades reales de las personas refugiadas, debemos aprender de las historias de personas como Meh Sod, que se reasentó en Estados Unidos con 12 años

Reappraisal of the toxicity test method using the green alga Ulva pertusa Kjellman (Chlorophyta),

This study was aimed to develop an objective way of quantifying the reproductive status of the green macroalga, Ulva pertusa using a vital stain and programmed automated analysis (by Image J program). The EC50 values (with 95% CI), the concentrations of toxicants inducing a reduction of 50% in sporulation after 96 h exposure, from the newly developed method were similar to those obtained by the conventional method: 0.651 (0.598-0.705) mg l(-1) for Cd, 0.144 (0.110-0.162) mg l(-1) for Cu, 0.180 (0.165-0.195) mg l(-1) for atrazine, 0.076 (0.049-0.094) mg l(-1) for diuron and 30.6 (26.5-34.4) ml l(-1) for DMSO, respectively. When the EC50 values from this study were compared to that those from literatures, the sensitivity for some toxicants was similar or higher than that of U. fasciata (1.930 mg l(-1) for germination for Cd), U. armoricana (0.250 mg l(-1) for Fv/Fm for Cu), U. reticulata (0.126-1.585 mg l(-1) for growth for Cu), and U. intestinalis (0.650 mg l(-1) for Fv/Fm for atrazine). The subjective views of the experimental performers can be eliminated using the newly developed method. The Ulva method gave consistent responses to Cu and Cd of internationally allowable ranges for effluents, implying that the method is a useful tool for monitoring industrial wastewaters containing these metals

Multiple and Consecutive Genome Editing Using i-GONAD and Breeding Enrichment Facilitates the Production of Genetically Modified Mice

Genetically modified (GM) mice are essential tools in biomedical research. Traditional methods for generating GM mice are expensive and require specialized personnel and equipment. The use of clustered regularly interspaced short palindromic repeats (CRISPR) coupled with improved-Genome editing via Oviductal Nucleic Acids Delivery (i-GONAD) has highly increased the feasibility of producing GM mice in research laboratories. However, genetic modification in inbred mouse strains of interest such as C57BL/6 (B6) is still challenging because of their low fertility and embryo fragility. We have successfully generated multiple novel GM mouse strains in the B6 background while attempting to optimize i-GONAD. We found that i-GONAD reduced the litter size in superovulated pregnant females but did not impact pregnancy rates. Natural mating or low-hormone dose did not increase the low fertility rate observed in superovulated B6 females. However, diet enrichment had a positive effect on pregnancy success. We also optimized breeding conditions to increase the survival of small litters by co-housing i-GONAD-treated pregnant B6 females with synchronized pregnant FVB/NJ companion mothers. Thus, GM mice generation was increased by an enriched diet and shared pup rearing with highly fertile females such as FVB/NJ. In the present study, we generated 16 GM mice using a CRISPR/Cas system to target individual and multiple loci simultaneously or consecutively. We also compared homology-directed repair efficiency using different methods for LoxP insertion for conditional knockout mouse production. We found that a two-step serial LoxP insertion, in which each LoxP sequence was inserted individually in different i-GONAD procedures, was a low-risk high-efficiency method for generating floxed mice

Stories told by refugee youth: alternatives to dominant narratives

Stories of children moving in and out of refugee camps are not uncommon yet are often overshadowed by the dominant narratives of oppression, political failure, and war—the stories told of rather than told by refugees. Dominant narratives on refugees largely shape perceptions about children and youth in displacement as vulnerable, voiceless, and passive. Instead, stories told by these populations highlight their identities as capable and determined. Employing a narrative approach to inquiry in relation to agency, this study seeks to understand how lived experiences of female refugee youth are shared through storytelling. Written narratives of 55 adolescent girls in Kakuma refugee camp in Kenya revealed not only the complex and complicated circumstances of their educational journey but also their agency. This paper concludes by emphasizing the importance of storytelling, which enables us to better understand the needs of the displaced populations, but also their capabilities, aspirations and agency

Can CRISPR Improve the Protein Secretion of Pichia pastoris

Pichia pastoris is a methylotrophic yeast that is widely used for protein expression, such as vaccines, anti-cancer proteins, and rheumatoid arthritis treatment proteins. Previously, the lab isolated a mutant strain called bgs13. It was assumed that the strain was a knockout; however, it was not. In this mutant, the bgs13 gene sequence was changed, and a modified protein was still being made that had kinase activity. The mutant had a lower than normal kinase activity and was a super secretor, meaning it was able to secrete increased levels of beta-galactosidase and other proteins. Our goal is to make a true knockout of bgs13 and observe its effect on the secretion levels of reporter proteins. We have attempted to abolish kinase activity by making a knockout with CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats), which targets the bgs13 gene in our studies. Having performed CRISPR, we are using colony PCR and sequence analysis to confirm that we have a strain in which the bgs13 sequence is edited to create an actual knockout. If we cannot isolate such a knockout strain, this would suggest that the bgs13 gene is necessary for survival. Thus, by searching for true knockouts of bgs13 with these methods, our results will help us figure out whether the bgs13 gene is essential for survival or can be knocked out to provide high levels of secretion

Origin of distorted 1T-ReS2 and quasi-1D phase transition in WxRe1-xS2

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Can CRISPR Improve the Protein Secretion of Pichia pastoris

Pichia pastoris is a methylotrophic yeast that is widely used for protein expression, such as vaccines, anti-cancer proteins, and rheumatoid arthritis treatment proteins. Previously, the lab isolated a mutant strain called bgs13. It was assumed that the strain was a knockout; however, it was not. In this mutant, the bgs13 gene sequence was changed, and a modified protein was still being made that had kinase activity. The mutant had a lower than normal kinase activity and was a super secretor, meaning it was able to secrete increased levels of beta-galactosidase and other proteins. Our goal is to make a true knockout of bgs13 and observe its effect on the secretion levels of reporter proteins. We have attempted to abolish kinase activity by making a knockout with CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats), which targets the bgs13 gene in our studies. Having performed CRISPR, we are using colony PCR and sequence analysis to confirm that we have a strain in which the bgs13 sequence is edited to create an actual knockout. If we cannot isolate such a knockout strain, this would suggest that the bgs13 gene is necessary for survival. Thus, by searching for true knockouts of bgs13 with these methods, our results will help us figure out whether the bgs13 gene is essential for survival or can be knocked out to provide high levels of secretion

Structural origin of ReS2 and quasi-1D phase transition in AxRe1-xS2 (A; W, Mo)

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Clinical practice experience of doctor of philosophy nurses in South Korea: a qualitative study

Purpose This study aimed to gain a broader understanding of the clinical practice experience of Doctor of Philosophy nurses working in nursing positions. Method Participants were 15 full-time nurses who are current Doctor of Philosophy candidates or have acquired a Doctor of Philosophy in nursing. Data were collected through face-to-face interviews and the participants’ diaries, which were analysed using a descriptive qualitative method. Results The patient care experiences of Doctor of Philosophy nurses in clinical practice were grouped into four themes: “providing evidence-based and patient-specific education,” “proactively taking responsible for communicating with patients,” “enhancing the quality of nursing through reflective attitudes,” and “advocating for patients using a multifaceted approach.” The factors facilitating or inhibiting clinical practice were identified with three themes. Conclusion This study revealed that the Doctor of Philosophy nurses used the knowledge and experience they gained in their Doctor of Philosophy nursing programme to serve as role models for the advancement of nursing education and evidence-based practice