Modeling Item-Level Spelling Variance in Adults: Providing Further Insights into Lexical Quality.

Purpose: The lexical quality (LQ) hypothesis predicts that a skilled reader's lexicon will be inhabited by a range of low- to high-quality items, and the probability of representing a word with high quality varies as a function of person-level, word-level, and item-specific variables. These predictions were tested with spelling accuracy as a gauge of LQ. Method: Item-response based crossed random effects models explored simultaneous contributions of person-level (e.g., participant's decoding skill), word-level (e.g., word's transparency rating), item-specific (e.g., participant's familiarity with specific word), and person-by-word interaction predictors (e.g., decoding by transparency rating interaction) to the spelling of 25 commonly misspelled irregular English words in 61 undergraduate university students (M = 19.4 years, 70.49% female, 39.34% Hispanic, 81.97% White). Results: Substantial variance among individuals in item-level spelling accuracy was accounted for by person-level decoding skill; item-specific familiarity, proportion of schwas correctly represented, and correctly identifying the word from its mispronunciation; and an interaction of transparency rating by general decoding skill. Conclusions: Consistent with the LQ hypothesis, results suggest that one's ability to form a high-quality lexical representation of a given word depends on a complex combination of person-level abilities, word-level characteristics, item-specific experiences, and an interaction between person- and word-level influences.

Induction of somatic cell haploidy by premature cell division.

Canonical mitotic and meiotic cell divisions commence with replicated chromosomes consisting of two sister chromatids. Here, we developed and explored a model of premature cell division, where nonreplicated, G0/G1-stage somatic cell nuclei are transplanted to the metaphase cytoplasm of mouse oocytes. Subsequent cell division generates daughter cells with reduced ploidy. Unexpectedly, genome sequencing analysis revealed proper segregation of homologous chromosomes, resulting in complete haploid genomes. We observed a high occurrence of somatic genome haploidization in nuclei from inbred genetic backgrounds but not in hybrids, emphasizing the importance of sequence homology between homologs. These findings suggest that premature cell division relies on mechanisms similar to meiosis I, where genome haploidization is facilitated by homologous chromosome interactions, recognition, and pairing. Unlike meiosis, no evidence of recombination between somatic cell homologs was detected. Our study offers an alternative in vitro gametogenesis approach by directly reprogramming diploid somatic cells into haploid oocytes.

Molecular basis for maternal inheritance of human mitochondrial DNA.

Uniparental inheritance of mitochondrial DNA (mtDNA) is an evolutionary trait found in nearly all eukaryotes. In many species, including humans, the sperm mitochondria are introduced to the oocyte during fertilization1,2. The mechanisms hypothesized to prevent paternal mtDNA transmission include ubiquitination of the sperm mitochondria and mitophagy3,4. However, the causative mechanisms of paternal mtDNA elimination have not been defined5,6. We found that mitochondria in human spermatozoa are devoid of intact mtDNA and lack mitochondrial transcription factor A (TFAM)-the major nucleoid protein required to protect, maintain and transcribe mtDNA. During spermatogenesis, sperm cells express an isoform of TFAM, which retains the mitochondrial presequence, ordinarily removed upon mitochondrial import. Phosphorylation of this presequence prevents mitochondrial import and directs TFAM to the spermatozoon nucleus. TFAM relocalization from the mitochondria of spermatogonia to the spermatozoa nucleus directly correlates with the elimination of mtDNA, thereby explaining maternal inheritance in this species.

Identifying Preservice Teachers’ Belief Profiles and their Performance in a Web-based Training for Writing Instruction / [La identificación de los perfiles de creencias de maestros y maestras en formación y su desempeño en un programa web de enseñanza de la escritura]

This research aims to fill the need to provide writing education to preservice teachers by using web-based instruction. The novel contribution of this work lies in the consideration of beliefs as a methodological prerequisite when measuring the effects of a web-based program. For this purpose, latent profile analysis was conducted to explore unique profiles of preservice teachers’ beliefs about writing before the web-based instruction. Participants were classified into three profiles: eclectic profile (n = 129), socio-cultural profile (n = 85), and person-environment profile (n = 105). Linear mixed-effects models were employed to assess if belief profiles experienced changes in beliefs and knowledge after the training. Results showed that belief profiles differed from each other in the degree of attribution of the different beliefs but remarkably all of them experienced significant differences in content knowledge acquisition. Finally, educational implications for preservice teachers’ education are highlighted.(AU)

Esta investigación tiene como objetivo cubrir la necesidad de proporcionar formación en la enseñanza de la escritura a maestros y maestras en formación mediante el uso de un programa web. La aportación novedosa de este trabajo radica en la consideración de las creencias como prerrequisito metodológico a la hora de medir los efectos de un programa web. Con este fin, antes de la instrucción web se realizó un análisis de perfiles latentes con el fin de explorar perfiles únicos de creencias sobre la escritura en maestros y maestras en formación. Se clasificó a los participantes en tres perfiles: perfil ecléctico (n = 129), sociocultural (n = 85) y persona-ambiente (n = 105). Se emplearon modelos mixtos lineales para evaluar si los perfiles de creencias experimentaban cambios en las creencias y el conocimiento después de la formación. Los resultados muestran que los perfiles de creencias difieren entre si en el grado de atribución de las diferentes creencias, pero todos ellos experimentan diferencias significativas en la adquisición del conocimiento de contenidos. Finalmente, se destacan las implicaciones educativas para la formación de futuros docentes.(AU)

Set for Variability as a Critical Predictor of Word Reading: Potential Implications for Early Identification and Treatment of Dyslexia.

Quasiregular orthographies such as English contain substantial ambiguities between orthography and phonology that force developing readers to acquire flexibility during decoding of unfamiliar words, a skill referred to as a "set for variability" (SfV). The ease with which a child can disambiguate the mismatch between the decoded form of a word and its actual lexical phonological form has been operationalized using the SfV mispronunciation task (e.g., the word wasp is pronounced to rhyme with clasp [i.e., /wæsp/] and the child must recognize the actual pronunciation of the word to be /wɒsp/). SfV has been shown to be a significant predictor of word reading variance. However, little is known about the relative strength of SfV as a predictor of word reading compared to other well-established predictors or the strength of this relationship in children with dyslexia. To address these questions, we administered the SfV task to a sample of grade 2-5 children (N=489) along with other reading related measures. SfV accounted for 15% unique variance in word reading above and beyond other predictors, whereas phonological awareness (PA) accounted for only 1%. Dominance analysis indicated SfV is the most powerful predictor, demonstrating complete statistical dominance over other variables including PA. Quantile regression revealed SfV is a stronger predictor at lower levels of reading skill, indicating it may be an important predictor in students with dyslexia. Results suggest that SfV is a powerful and potentially highly sensitive predictor of early reading difficulties and, therefore, may be important for early identification and treatment of dyslexia.

Limitations of gene editing assessments in human preimplantation embryos.

Range of DNA repair in response to double-strand breaks induced in human preimplantation embryos remains uncertain due to the complexity of analyzing single- or few-cell samples. Sequencing of such minute DNA input requires a whole genome amplification that can introduce artifacts, including coverage nonuniformity, amplification biases, and allelic dropouts at the target site. We show here that, on average, 26.6% of preexisting heterozygous loci in control single blastomere samples appear as homozygous after whole genome amplification indicative of allelic dropouts. To overcome these limitations, we validate on-target modifications seen in gene edited human embryos in embryonic stem cells. We show that, in addition to frequent indel mutations, biallelic double-strand breaks can also produce large deletions at the target site. Moreover, some embryonic stem cells show copy-neutral loss of heterozygosity at the cleavage site which is likely caused by interallelic gene conversion. However, the frequency of loss of heterozygosity in embryonic stem cells is lower than in blastomeres, suggesting that allelic dropouts is a common whole genome amplification outcome limiting genotyping accuracy in human preimplantation embryos.

Horizontal mtDNA transfer between cells is common during mouse development.

Cells transmit their genomes vertically to daughter cells during cell divisions. Here, we demonstrate the occurrence and extent of horizontal mitochondrial (mt)DNA acquisition between cells that are not in a parent-offspring relationship. Extensive single-cell sequencing from various tissues and organs of adult chimeric mice composed of cells carrying distinct mtDNA haplotypes showed that a substantial fraction of individual cardiomyocytes, neurons, glia, intestinal, and spleen cells captured donor mtDNA at high levels. In addition, chimeras composed of cells with wild-type and mutant mtDNA exhibited increased trafficking of wild-type mtDNA to mutant cells, suggesting that horizontal mtDNA transfer may be a compensatory mechanism to restore compromised mitochondrial function. These findings establish the groundwork for further investigations to identify mtDNA donor cells and mechanisms of transfer that could be critical to the development of novel gene therapies.

Haploidy in somatic cells is induced by mature oocytes in mice.

Haploidy is naturally observed in gametes; however, attempts of experimentally inducing haploidy in somatic cells have not been successful. Here, we demonstrate that the replacement of meiotic spindles in mature metaphases II (MII) arrested oocytes with nuclei of somatic cells in the G0/G1 stage of cell cycle results in the formation of de novo spindles consisting of somatic homologous chromosomes comprising of single chromatids. Fertilization of such oocytes with sperm triggers the extrusion of one set of homologous chromosomes into the pseudo-polar body (PPB), resulting in a zygote with haploid somatic and sperm pronuclei (PN). Upon culture, 18% of somatic-sperm zygotes reach the blastocyst stage, and 16% of them possess heterozygous diploid genomes consisting of somatic haploid and sperm homologs across all chromosomes. We also generate embryonic stem cells and live offspring from somatic-sperm embryos. Our finding may offer an alternative strategy for generating oocytes carrying somatic genomes.

Web-based Training Program for Writing Instruction: Preservice Teachers' Beliefs Profiles and Their Satisfaction.

BACKGROUND: Preservice teachers' satisfaction with online training should be considered to guarantee a successful e-learning experience. This study aims to determine whether preservice teachers' belief profiles influence their satisfaction with web-based training for teaching writing. METHOD: To achieve this purpose, two main analyses were conducted: (1) validation of a satisfaction's scale through Confirmatory Factor Analysis, and (2) MANOVA with independent inter-subject variables group belief profiles (i.e., Eclectic Profile, Socio-cultural Profile, and Person-environment Profile) and as dependent variables the five dimensions of the satisfaction scale. RESULTS: Results showed high satisfaction ratings with the web-based training in all the groups. Nevertheless, significant differences in satisfaction ratings were found between belief profiles. CONCLUSIONS: Finally, educational implications for preservice teachers' development are highlighted in the discussion.

Piloting the Response to Intervention Model in the Canary Islands: Prevention of Reading and Math Learning Disabilities.

The main objective of this study was to examine the effectiveness of an intervention implemented by elementary school teachers within the context of the Response to Intervention (RtI) model. For this purpose, a Tier 2 or secondary intervention was implemented by Spanish-speaking teachers in grades K-3 after receiving training to implement RtI components with fidelity. A total of 1,923 at-risk students were assigned to treatment (in reading, n = 542; in math, n = 483) or control (in reading, n = 406; in math, n = 492). Teachers were provided with a support system that included two web-based training programs for reading (i.e., Letra program) and math (i.e., Primate program). Implementation fidelity was analyzed using direct observations and self-reports. All students were assessed three times during the academic year. A hierarchical linear growth modeling was conducted, and differences in the growth rate of reading and math performance were analyzed between at-risk students who have received the intervention and those who have not received it. Children at-risk in the intervention condition appeared to benefit more than at-risk children in the control condition. Moreover, findings indicate that the earlier the intervention, the greater the percentage of students who leave the situation of risk of learning difficulties in reading and math.

Analyzing the role of fidelity of RTI Tier 2 reading intervention in Spanish kindergarten and first grade students.

This study examined the role of fidelity in the reading outcomes within a Tier 2 intervention implemented by Spanish kindergarten and first grade school teachers. For this purpose, differences in reading performance growth were analyzed among at-risk students who received a Tier 2 intervention with high fidelity, at-risk students who received the same intervention with medium fidelity, and an at-risk control group that did not receive a Tier 2 intervention. Implementation fidelity was analyzed using direct observations and self-reports. All students were assessed three times during the academic year. Hierarchical linear modeling analyses were conducted to explore differences in growth rate. The at-risk children in the intervention condition showed a higher growth compared to at-risk children in the control condition, and specifically when the intervention was delivered with a high degree of fidelity.

Germline transmission of donor, maternal and paternal mtDNA in primates.

STUDY QUESTION: What are the long-term developmental, reproductive and genetic consequences of mitochondrial replacement therapy (MRT) in primates? SUMMARY ANSWER: Longitudinal investigation of MRT rhesus macaques (Macaca mulatta) generated with donor mtDNA that is exceedingly distant from the original maternal counterpart suggest that their growth, general health and fertility is unremarkable and similar to controls. WHAT IS KNOWN ALREADY: Mitochondrial gene mutations contribute to a diverse range of incurable human disorders. MRT via spindle transfer in oocytes was developed and proposed to prevent transmission of pathogenic mtDNA mutations from mothers to children. STUDY DESIGN, SIZE, DURATION: The study provides longitudinal studies on general health, fertility as well as transmission and segregation of parental mtDNA haplotypes to various tissues and organs in five adult MRT rhesus macaques and their offspring. PARTICIPANTS/MATERIALS, SETTING, METHODS: MRT was achieved by spindle transfer between metaphase II oocytes from genetically divergent rhesus macaque populations. After fertilization of oocytes with sperm, heteroplasmic zygotes contained an unequal mixture of three parental genomes, i.e. donor (≥97%), maternal (≤3%), and paternal (≤0.1%) mitochondrial (mt)DNA. MRT monkeys were grown to adulthood and their development and general health was regularly monitored. Reproductive fitness of male and female MRT macaques was evaluated by time-mated breeding and production of live offspring. The relative contribution of donor, maternal, and paternal mtDNA was measured by whole mitochondrial genome sequencing in all organs and tissues of MRT animals and their offspring. MAIN RESULTS AND THE ROLE OF CHANCE: Both male and female MRT rhesus macaques containing unequal mixture of three parental genomes, i.e. donor (≥97%), maternal (≤3%), and paternal (≤0.1%) mtDNA reached healthy adulthood, were fertile and most animals stably maintained the initial ratio of parental mtDNA heteroplasmy and donor mtDNA was transmitted from females to offspring. However, in one monkey out of four analyzed, initially negligible maternal mtDNA heteroplasmy levels increased substantially up to 17% in selected internal tissues and organs. In addition, two monkeys showed paternal mtDNA contribution up to 33% in selected internal tissues and organs. LARGE SCALE DATA: N/A. LIMITATIONS, REASONS FOR CAUTION: Conclusions in this study were made on a relatively low number of MRT monkeys, and on only one F1 (first generation) female. In addition, monkey MRT involved two wildtype mtDNA haplotypes, but not disease-relevant variants. Clinical trials on children born after MRT will be required to fully determine safety and efficacy of MRT for humans. WIDER IMPLICATIONS OF THE FINDINGS: Our data show that MRT is compatible with normal postnatal development including overall health and reproductive fitness in nonhuman primates without any detected adverse effects. 'Mismatched' donor mtDNA in MRT animals even from the genetically distant mtDNA haplotypes did not cause secondary mitochondrial dysfunction. However, carry-over maternal or paternal mtDNA contributions increased substantially in selected internal tissues / organs of some MRT animals implying the possibility of mtDNA mutation recurrence. STUDY FUNDING/COMPETING INTEREST(S): This work has been funded by the grants from the Burroughs Wellcome Fund, the National Institutes of Health (RO1AG062459 and P51 OD011092), National Research Foundation of Korea (2018R1D1A1B07043216) and Oregon Health & Science University institutional funds. The authors declare no competing interests.

Web-based Training Program for Writing Instruction: Preservice Teachers’ Beliefs Profiles and Their Satisfaction / Programa Web Para la Enseñanza de la Escritura: Perfiles de Creencias y Satisfacción de Maestros en Formación

Background: Preservice teachers’ satisfaction with online training should be considered to guarantee a successful e-learning experience. This study aims to determine whether preservice teachers’ belief profiles influence their satisfaction with web-based training for teaching writing. Method: To achieve this purpose, two main analyses were conducted: (1) validation of a satisfaction’s scale through Confirmatory Factor Analysis, and (2) MANOVA with independent inter-subject variables group belief profiles (i.e., Eclectic Profile, Socio-cultural Profile, and Person-environment Profile) and as dependent variables the five dimensions of the satisfaction scale. Results: Results showed high satisfaction ratings with the web-based training in all the groups. Nevertheless, significant differences in satisfaction ratings were found between belief profiles. Conclusions: Finally, educational implications for preservice teachers’ development are highlighted in the discussion. (AU)

Antecedentes: para garantizar experiencias de formación en línea exitosas debe tenerse en consideración la satisfacción de los maestros/as en formación con la formación en línea. Este estudio tiene como objetivo determinar si los perfiles de creencias de los futuros maestros/as influyen en su satisfacción con una formación web para la enseñanza de la escritura. Método: para alcanzar este objetivo se llevaron a cabo dos análisis: (1) validación de una escala de satisfacción a través de un Análisis Factorial Confirmatorio, y (2) MANOVA con variables independientes inter-sujetos, perfiles de creencias grupales (i.e., Perfil Ecléctico, Perfil Sociocultural y Perfil Persona-Ambiente) y como variables dependientes las cinco dimensiones de la escala de satisfacción. Resultados: los resultados mostraron altos índices de satisfacción con la formación web en todos los grupos. Sin embargo, se encontraron diferencias significativas en las calificaciones de satisfacción entre los perfiles de creencias. Conclusiones: por último, en la discusión se destacan implicaciones educativas para el desarrollo profesional de los futuros maestros/as. (AU)

Universal Screening for Prevention of Reading, Writing, and Math Disabilities in Spanish.

The purpose of this study was to describe a Spanish protocol that includes reading, writing, and math Curriculum-Based Measures (CBMs) aimed at early detection of students at risk of presenting learning disabilities (LD). Early identification of LD is a critical component of the Response to Intervention (RtI) model. In early grades, the screening of foundational skills mentioned above can provide a data-based guideline for identifying students requiring a more intensive response-based intervention before starting elementary school. We designed different CBMs based on indicators of basic early reading, writing, and math skills [Indicadores de Progreso de Aprendizaje en Lectura, Escritura y Matemáticas, IPAL, IPAE, and IPAM respectively] that aim to fulfill the twofold objective of universal screening and evaluation of the Spanish students' progress. For reading, IPAL includes alphabetic principle, phonological awareness, concepts about print, and riddles in kindergarten. In first and second grades, IPAL includes alphabetic principle, nonsense words fluency, maze sentences, and oral reading fluency. In addition, it includes phonemic segmentation for first grade and prosody for second grade. For writing, IPAE includes copying letters, writing allographs, dictated letters, dictated words with arbitrary spelling, dictated words with rule-based spelling, dictated nonsense words, dictated sentences, writing sentences, and writing a story for first-third grades. Finally, for math, IPAM includes number comparison, missing number, number identification, quantity array, and counting aloud for kindergarten, and number comparison, multi-digit computation, missing number, single-digit computation, and place value for first-third grades.

Deleterious mtDNA mutations are common in mature oocytes.

Heritable mitochondrial DNA (mtDNA) mutations are common, yet only a few recurring pathogenic mtDNA variants account for the majority of known familial cases in humans. Purifying selection in the female germline is thought to be responsible for the elimination of most harmful mtDNA mutations during oogenesis. Here we show that deleterious mtDNA mutations are abundant in ovulated mature mouse oocytes and preimplantation embryos recovered from PolG mutator females but not in their live offspring. This implies that purifying selection acts not in the maternal germline per se, but during post-implantation development. We further show that oocyte mtDNA mutations can be captured and stably maintained in embryonic stem cells and then reintroduced into chimeras, thereby allowing examination of the effects of specific mutations on fetal and postnatal development.

Assessing Foundational Reading Skills in Kindergarten: A Curriculum-Based Measurement in Spanish.

Early identification of learning difficulties is a critical component of the Response to Intervention (RtI) model. In kindergarten, the screening of foundational reading skills can provide a data-based guideline for identifying students requiring a more intensive response-based intervention before starting elementary school. This study examines the classification accuracy and best predictors of a set of Spanish curriculum-based measures administered during kindergarten. The study's sample included 189 students tested in the fall, winter, and spring. Receiver operating characteristic (ROC) analysis was conducted. The composite score of the curriculum-based measurement (CBM) revealed area under the ROC curve (AUC) values of 0.83, 0.97, and 0.94 in the fall, winter, and spring, respectively. Phonemic awareness and letter-sound knowledge were the only isolated measures that demonstrated excellent AUC values throughout kindergarten. Logistic regression models showed that, when entered simultaneously, all measures were significant predictors of reading risk at some moment of the school year.

Author Correction: Mitochondrial replacement in human oocytes carrying pathogenic mitochondrial DNA mutations.

Change history In this Letter, there are several errors regarding the assignments of mtDNA haplotypes for a subset of egg donors from our study. These errors have not been corrected online.

Fibroblasts Mobilize Tumor Cell Glycogen to Promote Proliferation and Metastasis.

Successful metastasis requires the co-evolution of stromal and cancer cells. We used stable isotope labeling of amino acids in cell culture coupled with quantitative, label-free phosphoproteomics to study the bidirectional signaling in ovarian cancer cells and human-derived, cancer-associated fibroblasts (CAFs) after co-culture. In cancer cells, the interaction with CAFs supported glycogenolysis under normoxic conditions and induced phosphorylation and activation of phosphoglucomutase 1, an enzyme involved in glycogen metabolism. Glycogen was funneled into glycolysis, leading to increased proliferation, invasion, and metastasis of cancer cells co-cultured with human CAFs. Glycogen mobilization in cancer cells was dependent on p38α MAPK activation in CAFs. In vivo, deletion of p38α in CAFs and glycogen phosphorylase inhibition in cancer cells reduced metastasis, suggesting that glycogen is an energy source used by cancer cells to facilitate metastatic tumor growth.

Germline and somatic mtDNA mutations in mouse aging.

The accumulation of acquired mitochondrial genome (mtDNA) mutations with aging in somatic cells has been implicated in mitochondrial dysfunction and linked to age-onset diseases in humans. Here, we asked if somatic mtDNA mutations are also associated with aging in the mouse. MtDNA integrity in multiple organs and tissues in young and old (2-34 months) wild type (wt) mice was investigated by whole genome sequencing. Remarkably, no acquired somatic mutations were detected in tested tissues. However, we identified several non-synonymous germline mtDNA variants whose heteroplasmy levels (ratio of normal to mutant mtDNA) increased significantly with aging suggesting clonal expansion of inherited mtDNA mutations. Polg mutator mice, a model for premature aging, exhibited both germline and somatic mtDNA mutations whose numbers and heteroplasmy levels increased significantly with age implicating involvement in premature aging. Our results suggest that, in contrast to humans, acquired somatic mtDNA mutations do not accompany the aging process in wt mice.