Willingness to communicate (WTC), which plays a crucial role in second or foreign language learning, has a dynamic and complex nature, fluctuating during communicative events. This study examines how ...the situational WTC of four Japanese speakers of English as a foreign language (EFL) emerges and fluctuates, focusing on the roles of language proficiency and affective and conditional factors. Low-intermediate and advanced speakers were engaged in an interactive, communicative activity with an interlocutor. All utterances were recorded, transcribed, and analysed and combined with the qualitative data from participants’ self-ratings and a stimulated recall interview after the activity to assess fluctuations in WTC. The findings indicate that levels of WTC are influenced differently between low-intermediate and advanced speakers. Although the WTC of all speakers was negatively affected when they sensed a lack of English proficiency, low-intermediate speakers were affected by interest in the topic, influence of interlocutors on sense of security, and self-confidence, while opportunity to talk about oneself and one’s opinions contributed to the WTC of advanced speakers. It is suggested that teaches of EFL should be considerate of these factors that can affect EFL learners’ WTC.
Willingness to Communicate (WTC) plays a crucial role in second language (L2) learning, and is believed to be closely related to learning in general; the higher a learner's WTC, the better their ...fluency with the L2. WTC can also be conceptualized as fluctuating from moment to moment during the course of L2 use and communication. This also seems to be true for EFL teachers when conducting classes in the target language, but to date, this has not been tested empirically. Thus, this study explores a Japanese EFL teacher's WTC, focusing on its fluctuation over the course of a lesson. All the teacher's oral L2 and L1 utterances in an EFL class were audio and video-recorded for the analysis, which was based on the quantitative data of the teacher's self-rating of WTC for each utterance, and qualitative data obtained through a stimulated recall interview after the lesson. The results of this observational case study show that the teacher's WTC both increased and decreased. The factors underlying this fluctuating WTC are analyzed through the interview, while the implications of the study and further study directions are also discussed.
Diols are versatile chemicals used for multiple manufacturing products. In some previous studies,
Escherichia coli
has been engineered to produce 1,2-propanediol (1,2-PDO) and 1,3-propanediol ...(1,3-PDO) from glucose. However, there are no reports on the direct production of these diols from starch instead of glucose as a substrate. In this study, we directly produced 1,2-PDO and 1,3-PDO from starch using
E. coli
engineered for expressing a heterologous α-amylase, along with the expression of 1,2-PDO and 1,3-PDO synthetic genes. For this, the recombinant plasmids, pVUB3-SBA harboring
amyA
gene for α-amylase production, pSR5 harboring
pct
,
pduP
, and
yahK
genes for 1,2-PDO production, and pSR8 harboring
gpd1-gpp2
,
dhaB123
,
gdrAB
, and
dhaT
genes for 1,3-PDO production, were constructed. Subsequently,
E. coli
BW25113 (
ΔpflA
) and BW25113 strains were transformed with pVUB3-SBA, pSR5, and/or pSR8. Using these transformants, direct production of 1,2-PDO and 1,3-PDO from starch was demonstrated under microaerobic condition. As a result, the maximum production titers of 1,2-PDO and 1,3-PDO from 1% glucose as a sole carbon source were 13 mg/L and 150 mg/L, respectively. The maximum production titers from 1% starch were similar levels (30 mg/L 1,2-PDO and 120 mg/L 1,3-PDO). These data indicate that starch can be an alternative carbon source for the production of 1,2-PDO and 1,3-PDO in engineered
E. coli
. This technology could simplify the upstream process of diol bioproduction.
This paper describes an observational study with three Japanese EFL teachers that examined: (1) the difference in the frequencies of non-verbal behaviors (NVBs) depending on the amount of the second ...language (L2) used by the teacher; (2) the kinds of NVBs the Japanese EFL teachers used in the classes, and (3) the difference in frequency of NVB use depending on whether the same teacher used their first language (L1) or L2. An analysis of the findings indicated the following: (1) the greater the amount of teacher output of L2, the more frequently NVBs were used; (2) the teachers used different types of NVBs depending on the situation; and (3) NVBs were more frequently used when the teacher spoke L2. These findings suggest that NVBs play a crucial role in providing comprehensible input in EFL classrooms. The pedagogical implications for EFL teachers and teacher educators are also suggested in the conclusion.
Bacillus subtilis 168 has been explored as a platform for the synthesis and transmission of large DNA. Two inherent DNA incorporation systems, natural transformation and pLS20-based conjugation ...transfer, enable rapid handling of target DNA. Both systems are affected by the Bsu restriction-modification system that recognizes and cleaves unmethylated XhoI sites, limiting the choice of target DNA. We constructed B. subtilis 168 with stable mutation for restriction-deficient and modification-proficient (r-m+). It was demonstrated that the r - m ± strains can incorporate and transfer synthesized DNA with multiple Xho I sites. These should be of value as hub strains to integrate and disseminate giant DNA between B. subtilis 168 derivatives.
Escherichia coli JM109 (pGV3-SBA) can assimilate starch by fusing the starch-digesting enzyme α-amylase from Streptococcus bovis NRIC1535 to an OprI′ lipoprotein anchor on the cell membrane. This ...study shows microbial fuel cells (MFCs) development using this recombinant type of E. coli and starch as fuel. We observed the current generation of MFCs with E. coli JM109 (pGV3-SBA) for 120 h. During this period, it consumed 7.1 g/L of starch. A mediator in the form of anthraquinone-2,6-disulfonic acid disodium salt at 0.2, 0.4, and 0.8 mM was added to the MFCs. The highest maximum-current density (271 mA/m2) and maximum-power density (29.3 mW/m2) performances occurred in the 0.4 mM mediator solution. Coulomb yields were calculated as 3.4%, 3.0%, and 3.5% in 1.0, 5.0, and 10.0 g/L of initial starch, respectively. The concentrations of acetic acid, succinic acid, fumaric acid, and ethanol as metabolites were determined. In particular, 38.3 mM of ethanol was produced from 7.1 g/L of starch. This study suggests the use of recombinant E. coli which can assimilate starch present in starch-fueled MFCs. Moreover, it proposes the possibility of gene recombination technology for using wide variety of biomass as fuel and improving MFC's performance.
Abstract
Synechococcus elongatus PCC7942, a cyanobacterium that uses light and carbon dioxide to grow, has a high ability to incorporate DNA by transformation. To assess the effective delivery of ...large DNA in plasmid form, we cloned the endogenous plasmid pANL (46.4 kbp) into a BAC vector of Escherichia coli. The plasmid p38ANL (54.3 kbp) replaced the native plasmid. To assess the delivery of larger DNA into PCC7942, p38ANL was fused to the broad-host-range conjugal transfer plasmid pUB307IP (53.5 kbp). The resulting plasmid pUB307IP501 (107.9 kbp) was transmitted from E. coli to PCC7942 by simple mixing of donor and recipient cultures. PCC7942 transcipients possessed only pUB307IP501, replacing the preexisting pANL. In contrast, the pUB307IP501 plasmid was unable to transform PCC7942, indicating that natural transformation of DNA may be restricted by size limitations. The ability to deliver large DNA by conjugation may lead to genetic engineering in PCC7942.
1,2-propanediol (1,2-PDO) is a versatile chemical used in multiple manufacturing processes. To date, some engineered and non-engineered microbes, such as
Escherichia coli, Lactobacillus buchneri,
and
...Clostridium thermosaccharolyticum,
have been used to produce 1,2-PDO. In this study, we demonstrated the production of
R
- and
S
-1,2-PDO using engineered
Lactococcus lactis
. The L- and D-lactic acid-producing
L. lactis
strains NZ9000 and AH1 were transformed with the plasmid pNZ8048-ppy harboring
pct
,
pduP
, and
yahK
genes for 1,2-PDO biosynthesis, resulting in
L. lactis
LL1 and LL2, respectively. These engineered
L. lactis
produced
S
- and
R
-1,2-PDO at concentrations of 0.69 and 0.50 g/L with 94.4 and 78.0%
ee
optical purities, respectively, from 1% glucose after 72 h of cultivation. Both 1% mannitol and 1% gluconate were added instead of glucose to the culture of
L. lactis
LL1 to supply NADH and NADPH to the 1,2-PDO production pathway, resulting in 75% enhancement of
S
-1,2-PDO production. Production of
S
-1,2-PDO from 5% mannitol and 5% gluconate was demonstrated using
L. lactis
LL1 with a pH–stat approach. This resulted in
S
-1,2-PDO production at a concentration of 1.88 g/L after 96 h of cultivation. To our knowledge, this is the first report on the production of
R
- and
S
-1,2-PDO using engineered lactic acid bacteria.
Glyoxylates are essential intermediates in several metabolic pathways and have a broad range of industrial applications. In this study, we propose a novel method for producing glyoxylate from glucose ...using engineered Escherichia coli BW25113. To direct the production of glyoxylate from glucose, malate synthase A (aceB), malate synthase G (glcB), glyoxylate carboligase (gcl), and glyoxylate/hydroxypyruvate reductase A (ycdW) genes were disrupted, and the glyoxylate shunt was reinforced in the disruptants by the overexpression of citrate synthase (gltA) and isocitrate lyase (aceA). In flask cultivation using M9 medium supplemented with 1% glucose, the disruptant E. coli BW25113 ΔaceB ΔglcB Δgcl ΔycdW produced 0.93 ± 0.17 g/L of glyoxylate. Further overexpression of gltA and aceA in the disruptant resulted in an improvement in glyoxylate production to 1.15 ± 0.02 g/L. By expressing a heterologous gene, pyc, in the engineered E. coli, the accumulation of intracellular oxaloacetate remarkably improved, leading to glyoxylate production of up to 2.42 ± 0.00 g/L with specific productivity at 4.22 ± 0.09 g/g-cell. To date, this is the highest reported titer and specific productivity of glyoxylate in E. coli.
This observational study was conducted to examine the effects of Japanese English as a foreign language (EFL) teachers' gestures on their second language (L2) utterances in EFL lessons. Two English ...lessons, one in a public senior high school and another in a private junior high school, taught by Japanese EFL teachers were video and audio recorded, transcribed, and analyzed. The teachers' L2 utterances were analyzed in terms of complexity, accuracy, and fluency to examine the following: (1) whether there is a difference between L2 utterances with and without gestures and (2) whether there is a difference in the effect of gestures according to their types. The results were as follows: (1) L2 utterances are more complex and fluent with gestures but accuracy was equal when accompanied by gestures and (2) there is a difference in the relations of some specific types of gestures to L2 utterances, with metaphoric gestures showing the highest scores in complexity and fluency and emblems the lowest. These findings suggest that teachers’ gestures play a crucial role in EFL classrooms, and therefore, should be given more consideration in L2 teacher education and training programs.
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