Teaching a small foreign language vocabulary to children using tact and listener instruction with a prompt delay.

This study consisted of a systematic replication of previous research examining the effects of tact and listener instruction on the emergence of native-to-foreign (NF) and foreign-to-native (FN) intraverbals in children who had experienced difficulties learning to read and write. We assigned different sets of stimuli to tact and listener conditions, and taught 4 children to tact or respond as listeners in a foreign language using a progressive prompt delay with differential reinforcement. All participants mastered tacts and listener responses in the foreign language. For all participants, tact instruction yielded greater emergence of intraverbals compared to listener instruction. Tact instruction also produced all possible bidirectional (NF and FN) intraverbals relations for 3 of 4 participants, but listener instruction never resulted in the emergence of all possible relations. These results replicate previous findings suggesting that tact instruction is a more efficient way to teach a foreign language and extend them to progressive prompt-delay procedures.

Fungal endophytes from leaves of Mandevilla catimbauensis (Apocynaceae): diversity and potential for L-asparaginase production.

In this study, we examined endophytic fungi in leaves of Mandevilla catimbauensis, an endemic plant species found in the Brazilian dry forest (Caatinga), and endophytic fungi's potential to produce L-asparaginase (L-ASNase). In total, 66 endophytes were isolated, and the leaf-fragment colonisation rate was 11.78%. Based on morphology, internal transcribed spacer (ITS), and partial large subunit (LSU) of ribosomal DNA sequencing, the endophytic fungi isolated belonged to six Ascomycota orders (Botryosphaeriales, Capnodiales, Diaporthales, Eurotiales, Marthamycetales, and Pleosporales). Phyllosticta species were the most frequent endophytes isolated (23 isolates [45.1%] from two species). The Shannon-Wiener and Fisher alpha index average values were 0.56 and 3.26, respectively. Twenty endophytes were randomly selected for the L-ASNase production test, of which fourteen isolates showed potential to produce the enzyme (0.48-2.22 U g-1), especially Phyllosticta catimbauensis URM 7672 (2.22 U g-1) and Cladosporium sp. G45 (2.11 U g-1). Phyllosticta catimbauensis URM 7672 was selected for the partial optimisation of L-ASNase production because of its ability to generate considerable amounts of enzyme. We obtained the highest L-ASNase activity (3.47 U g-1), representing an increase of 36.02% in enzymatic production, under the following experimental conditions: a pH of 4.2, 1.0% inoculum concentration, and 2.5% L-asparagine concentration. Our study showed that M. catimbauensis harbours an important diversity of endophytic fungi with biotechnological potential for L-ASNase production.