Search

Abstract Background Giardia duodenalis, a single-celled intestinal parasite, is divided into eight assemblages (A-H), with differences in host specificity. Giardia duodenalis reproduces asexually and cycles between the binucleated trophozoite (4 N) and the infectious cyst with four nuclei (16 N). Interaction between the nuclei is limited. Therefore, genetic drift causes differences in genetic make-up between the non-daughter nuclei; the allelic sequence heterozygosity (ASH). The ASH is low (0.01%—0.0023%) for the related assemblages A and E, higher (0.43–0.53) for assemblage B and much higher (0.74% -0.89%) for the assemblage C and D at the root of the phylogenetic tree. The heterozygosity in assemblage F, in the same clade as assemblage A and E, was unknown. The heterozygosity in the sequences of the gdh and dis3 genes was used as proxy for the ASH and whole genome amplification of single cysts followed by cloning and Sanger sequencing of dis3 fragment could reveal the genetic variation within the cyst. The aim of the study was to determine the level of heterozygosity within pooled and single cysts of different assemblages. Results The heterozygosity in gdh and dis3 was determined in pooled cysts of the assemblages A to F. Heterozygosity in the isolates of the assemblages C (n = 2) and D (n = 1) ranged from 0.41% to 0.82% for gdh and dis3 and no heterozygosity was found in the isolates of the assemblages A (n = 4), E (n = 3) and F (n = 3). The heterozygosity in assemblage B (n = 7) was intermediate (0% to 0.62%). Next, the number of haplotypes of dis3 was determined for single cysts of assemblages C, D and E. In the assemblages C and D, two to four haplotypes were found per cyst, while in assemblage E only one haplotype was identified. Conclusions Having high heterozygosity is characteristic for the assemblages C and D, while having a low heterozygosity is characteristic for the clade with the assemblages A, E and F. Presence of more than 1 haplotype per cyst in assemblage C and D suggests differences between the non-daughter nuclei, in contrast to the one haplotype in assemblage E.

This study investigates the influences of early and intense L2 exposure on children's L1 causative verb production, assessed by an experimental causative verb production task. Turkish expresses causality by morphological and lexical means, whereas English does so by periphrastic and lexical means. Learning L2 English might enhance L1 Turkish causative verb production by highlighting the parallels and contrasts in causal expressions between the languages, which may result in an enriched L1 causative use. Five-, 7 -, and 9-year-old L1-Turkish L2-English bilingual (n = 80) and L1-Turkish monolingual (n = 80) children participated in the study in L1-Turkish. Results indicated that language group differences only emerged for the use of morphological causative verbs in favor of 5-year-old bilinguals compared with monolingual peers. Age group differences occurred only for the monolingual group and only for morphological verbs. Specifically, monolingual 7- and 9-year-olds performed better than monolingual 5-year-olds. Causative verb-type differences were only seen for 5-year-old monolinguals, who performed better for lexical than morphological verbs; in contrast, 5-year-old bilinguals performed equally well on the two types of causatives, and better than 5-year-old monolinguals on morphological causatives. Overall, these findings indicate that learning an L2 with structural similarities and differences compared with L1 might enhance children's awareness and correct use of causal linguistic structures.

DNA damage repair (DDR) is mediated by phosphorylating effectors ATM kinase, CHK2, p53, and γH2AX. We showed earlier that GH suppresses DDR by suppressing pATM, resulting in DNA damage accumulation. Here, we show GH acting through GH receptor (GHR) inducing wild-type p53-inducible phosphatase 1 (WIP1), which dephosphorylated ATM and its effectors in normal human colon cells and three-dimensional human intestinal organoids. Mice bearing GH-secreting xenografts exhibited induced colon WIP1 with suppressed pATM and γH2AX. WIP1 was also induced in buffy coats derived from patients with elevated GH from somatotroph adenomas. In contrast, decreased colon WIP1 was observed in GHR-/- mice. WIP1 inhibition restored ATM phosphorylation and reversed GH-induced DNA damage. We elucidated a novel GH signaling pathway activating Src/AMPK to trigger HIPK2 nuclear-cytoplasmic relocation and suppressing WIP1 ubiquitination. Concordantly, blocking either AMPK or Src abolished GH-induced WIP1. We identify WIP1 as a specific target for GH-mediated epithelial DNA damage accumulation.

Despite the recent completion of the human genome project, the mapping of disease-related chromosomal translocation breakpoints and genes has remained laborious. Here, we describe a novel and rapid procedure to map such translocation breakpoints using flow-sorted chromosomes in combination with array-based comparative genomic hybridization (arrayCGH). To test the feasibility of this approach, we used a t(12;15)(q13;q25)-positive cell line with known breakpoint positions as a model. The derivative 12 chromosomes were flow-sorted, labeled, and hybridized to a genome-wide array containing 3648 well-characterized human genomic clones. The exact locations of the breakpoints on both chromosome 12 and 15 could be determined in a single hybridization experiment. In addition, we have tested the minimal amount of material necessary to perform these experiments and show that it is possible to obtain highly reliable profiles using as little as 10,000 flow-sorted chromosomes.

Three colleagues critically reflect on their experiences as educators, curriculum designers, leaders, and activists who set out to apply social justice education and transformative leadership scholarship to the creation of a Leaders of Social Justice in Education course. They begin with their background, the diverse change agents selected to build a movement of leaders, and the educational context. Second, a theoretical framework is presented to explain the overall goals of the project and the development of the course. Third, the course curriculum and website created during the COVID-19 pandemic is described, specifically the culminating Social Justice Action Project. Fourth, outcomes of the project are identified, including lessons learned about transformative leadership in the context of social justice education. At the paper's conclusion, the authors reflect on the course and explain why ongoing learning opportunities, structures, and collaboratives are needed for cultivating and nurturing the next generation of leaders in social justice education.

The Hmong people are an ethnic group from Southeast Asia. Hmong Americans came to this country as refugees from Laos. Serving as the fabric of the Hmong community, the "1.5 generation" is the unique generation of those born in Laos or Thai refugee camps and transported to America in their childhood. They represent the link between their parents, who lived through the war and are fluent in Hmong, and their children or younger family members, who were born in America and are fluent in English. They successfully made the transition from immigrants to active citizens. They are the community advocates that are trying to bridge the Hmong communities they live in with the mainstream. This generation are the mentors and role models that pave the way for future and younger generations of Hmong Americans to follow. Ger Thao is of the 1.5 generation and and presents her story herein. As a doctoral student and educator who strives to teach and engage in anti-bias, multicultural/multilingual, and social justice education, she uses the Teaching Tolerance (Southern Poverty Law Center, 1991) Social Justice Standards as a framework to walk the reader through her journey from immigrant to scholar. The standards are divided into four domains: Identity, Diversity, Justice, and Action. These are based on Louise Derman-Sparks' (Derman-Sparks, Edwards, & NAEYC, 2010) four goals for anti-bias education in early childhood: Identity, Diversity, Justice, and Activism.

Becoming productive with grammatical categories is a gradual process in children's language development. Here, we investigated this transition process by focusing on Turkish causatives. Previous research examining spontaneous and elicited production of Turkish causatives with familiar verbs attested the onset and early stages of productivity at ages 2 to 3 (Aksu-Koç & Slobin, 1985; Nakipoglu, Uzundag, & Sarigül, 2021). So far, however, we know very little about children's understanding of causatives with novel verbs. In the present study, we asked: (a) When does the generalization of causative morphology in a novel context emerge? and (b) What role does child-directed input play in this development? To answer the first question, we conducted comprehension-judgment experiments with children aged 2;6-6;1 using pseudo-verbs (Study 1 & 2). Results showed that children preferred the Turkish causative suffix -DIr over an unrelated or no suffix to denote caused events earliest at age 4;10. To answer the second question, we analyzed child-directed speech from a longitudinal corpus of Turkish language acquisition (Study 3). Results showed that when addressing children younger than age 3, caregivers used the -DIr suffix with little variation considering the overall variability of verbs they could utter. Overall, these findings suggest that productivity with morphological causatives in a novel context emerges in a later stage of acquisition. This later development might partly be accounted for by the insufficient variation of morphological causatives in the early input.