L2 Acquisition of English Binding Domains

Many biological effects of complex carbohydrates are mediated by lectins that contain discrete carbohydrate-recognition domains. At least seven structurally distinct families of carbohydrate-recognition domains are found in lectins that are involved in intracellular trafficking, cell adhesion, cell–cell signalling, glycoprotein turnover and innate immunity. Genome-wide analysis of potential carbohydrate-binding domains is now possible. Two classes of intracellular lectins involved in glycoprotein trafficking are present in yeast, model invertebrates and vertebrates, and two other classes are present in vertebrates only. At the cell surface, calcium-dependent (C-type) lectins and galectins are found in model invertebrates and vertebrates, but not in yeast; immunoglobulin superfamily (I-type) lectins are only found in vertebrates. The evolutionary appearance of different classes of sugar-binding protein modules parallels a development towards more complex oligosaccharides that provide increased opportunities for specific recognition phenomena. An overall picture of the lectins present in humans can now be proposed. Based on our knowledge of the structures of several of the C-type carbohydrate-recognition domains, it is possible to suggest ligand-binding activity that may be associated with novel C-type lectin-like domains identified in a systematic screen of the human genome. Further analysis of the sequences of proteins containing these domains can be used as a basis for proposing potential biological functions.

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A View of the Lexical–Grammatical Link in Young Latinos With Specific Language Impairment Using Language-Specific and Conceptual Measures

Journal of Speech Language and Hearing Research ◽

10.1044/2019_jslhr-l-18-0315 ◽

2019 ◽

Vol 62 (6) ◽

pp. 1775-1786 ◽

Cited By ~ 2

Author(s):

Lucía I. Méndez ◽

Gabriela Simon-Cereijido

Keyword(s):

Low Income ◽

Language Impairment ◽

Specific Language Impairment ◽

L2 Acquisition ◽

Cross Sectional ◽

Specific Language ◽

Vocabulary Skills ◽

In The Beginning ◽

Study Participants ◽

L1 And L2

Purpose This study investigated the nature of the association of lexical–grammatical abilities within and across languages in Latino dual language learners (DLLs) with specific language impairment (SLI) using language-specific and bilingual measures. Method Seventy-four Spanish/English–speaking preschoolers with SLI from preschools serving low-income households participated in the study. Participants had stronger skills in Spanish (first language [L1]) and were in the initial stages of learning English (second language [L2]). The children's lexical, semantic, and grammar abilities were assessed using normative and researcher-developed tools in English and Spanish. Hierarchical linear regressions of cross-sectional data were conducted using measures of sentence repetition tasks, language-specific vocabulary, and conceptual bilingual lexical and semantic abilities in Spanish and English. Results Results indicate that language-specific vocabulary abilities support the development of grammar in L1 and L2 in this population. L1 vocabulary also contributes to L2 grammar above and beyond the contribution of L2 vocabulary skills. However, the cross-linguistic association between vocabulary in L2 and grammar skills in the stronger or more proficient language (L1) is not observed. In addition, conceptual vocabulary significantly supported grammar in L2, whereas bilingual semantic skills supported L1 grammar. Conclusions Our findings reveal that the same language-specific vocabulary abilities drive grammar development in L1 and L2 in DLLs with SLI. In the early stages of L2 acquisition, vocabulary skills in L1 also seem to contribute to grammar skills in L2 in this population. Thus, it is critical to support vocabulary development in both L1 and L2 in DLLs with SLI, particularly in the beginning stages of L2 acquisition. Clinical and educational implications are discussed.

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Combination of ribosome and phage display for fast selection of high affinity VHH antibody fragments

Bulletin of Russian State Medical University ◽

10.24075/brsmu.2019.002 ◽

2019 ◽

pp. 27-33

Author(s):

YuE Kravchenko ◽

SV Ivanov ◽

DS Kravchenko ◽

EI Frolova ◽

SP Chumakov

Keyword(s):

Phage Display ◽

Selection Procedure ◽

Free System ◽

Phage Displays ◽

High Affinity ◽

Binding Domains ◽

A Cell ◽

Vhh Antibodies ◽

Efficiency Of Selection ◽

Selection Of

Selection of antibodies using phage display involves the preliminary cloning of the repertoire of sequences encoding antigen-binding domains into phagemid, which is considered the bottleneck of the method, limiting the resulting diversity of libraries and leading to the loss of poorly represented variants before the start of the selection procedure. Selection in cell-free conditions using a ribosomal display is devoid from this drawback, however is highly sensitive to PCR artifacts and the RNase contamination. The aim of the study was to test the efficiency of a combination of both methods, including pre-selection in a cell-free system to enrich the source library, followed by cloning and final selection using phage display. This approach may eliminate the shortcomings of each method and increase the efficiency of selection. For selection, alpaca VHH antibody sequences suitable for building an immune library were used due to the lack of VL domains. Analysis of immune libraries from the genes of the VH3, VHH3 and VH4 families showed that the VHH antibodies share in the VH3 and VH4 gene groups is insignificant, and selection from the combined library is less effective than from the VHH3 family of sequences. We found that the combination of ribosomal and phage displays leads to a higher enrichment of high-affinity fragments and avoids the loss of the original diversity during cloning. The combined method allowed us to obtain a greater number of different high-affinity sequences, and all the tested VHH fragments were able to specifically recognize the target, including the total protein extracts of cell cultures.

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An exploration of target L2 morphemes in the oral production of young EFL learners in Croatia

10.31234/osf.io/w6j2z ◽

2020 ◽

Author(s):

Jelena O'Reilly ◽

Eva Jakupčević

Keyword(s):

Foreign Language ◽

Research Area ◽

Simple Construction ◽

L2 Acquisition ◽

Efl Learners ◽

Oral Production ◽

The Past ◽

Base Form ◽

Production Study ◽

Efl Students

Although the second language (L2) acquisition of morphology by late L2 learners has been a popular research area over the past decades, comparatively little is known about the acquisition and development of morphology in children who learn English as a foreign language (EFL). Therefore, the current study presents the findings from a longitudinal oral production study with 9/10-year-old L1 Croatian EFL students who were followed up at the age of 11/12. Our results are largely in line with the limited research so far in this area: young EFL learners have few issues using the be copula and, eventually, the irregular past simple forms, but had considerable problems with accurately supplying the 3rd person singular -s at both data collection points. We also observed a be + base form structure, especially at the earlier stage, which appears to be an emergent past simple construction.

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