Rethinking Literacy Intervention: Addressing a Practice Gap With Best Practices From Multisensory Structured Language Approaches.

PURPOSE: Dyslexia is increasingly being defined, assessed, diagnosed, and treated in the educational system. The purpose of this clinical focus article is to elucidate ways in which speech-language pathologists (SLPs) can rethink how to implement literacy interventions to incorporate best practices from multisensory structured language (MSL) approaches and how they can be influential participants in the conversations of how to define and implement services for students who have written language disorders, including dyslexia, in the school setting. METHOD: This clinical focus article provides an operational definition of dyslexia, discusses the various roles and responsibilities of SLPs with respect to dyslexia, and describes the well-established evidence-based practices of MSL approaches as a means of rethinking literacy intervention. RESULTS: Using a case study scenario based on an individual diagnosed with dyslexia, this clinical focus article presents similarities and differences between traditional speech-language pathology intervention approaches and MSL approaches to literacy intervention. CONCLUSIONS: MSL strategies may be considered in literacy intervention as a means to optimize the academic gains of children with dyslexia in a school setting. Furthermore, SLPs should be considered integral participants in discussions of policies and practices related to the diagnosis and treatment of literacy disorders, including dyslexia. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.23228483.

Phonological working memory in developmental stuttering: Potential insights from the neurobiology of language and cognition.

The current review examines how neurobiological models of language and cognition could shed light on the role of phonological working memory (PWM) in developmental stuttering (DS). Toward that aim, we review Baddeley's influential multicomponent model of PWM and evidence for load-dependent differences between children and adults who stutter and typically fluent speakers in nonword repetition and dual-task paradigms. We suggest that, while nonword repetition and dual-task findings implicate processes related to PWM, it is unclear from behavioral studies alone what mechanisms are involved. To address how PWM could be related to speech output in DS, a third section reviews neurobiological models of language proposing that PWM is an emergent property of cyclic sensory and motor buffers in the dorsal stream critical for speech production. We propose that anomalous sensorimotor timing could potentially interrupt both fluent speech in DS and the emergent properties of PWM. To further address the role of attention and executive function in PWM and DS, we also review neurobiological models proposing that prefrontal cortex (PFC) and basal ganglia (BG) function to facilitate working memory under distracting conditions and neuroimaging evidence implicating the PFC and BG in stuttering. Finally, we argue that cognitive-behavioral differences in nonword repetition and dual-tasks are consistent with the involvement of neurocognitive networks related to executive function and sensorimotor integration in PWM. We suggest progress in understanding the relationship between stuttering and PWM may be accomplished using high-temporal resolution electromagnetic experimental approaches.

SucA-dependent uptake of sucrose across the outer membrane of Caulobacter crescentus.

Caulobacter crescentus is an aquatic Gram-negative bacterium that lives in nutrient-poor environments. Like several other aquatic and phytopathogenic bacteria, Caulobacter cells have a relatively large number of genes predicted to encode TonB-dependent receptors (TBDRs). TBDRs transport nutrients across the outer membrane using energy from the proton motive force. We identified one TBDR gene, sucA, which is situated within a cluster of genes predicted to encode a lacI-family transcription factor (sucR), amylosucrase (sucB), fructokinase (sucC), and an inner membrane transporter (sucD). Given its genomic neighborhood, we proposed that sucA encodes a transporter for sucrose. Using RT-qPCR, we determined that expression of sucABCD is strongly induced by sucrose in the media and repressed by the transcription factor, SucR. Furthermore, cells with a deletion of sucA have a reduced uptake of sucrose. Although cells with a non-polar deletion of sucA can grow with sucrose as the sole carbon source, cells with a polar deletion that eliminates expression of sucABCD cannot grow with sucrose as the sole carbon source. These results show that the suc locus is essential for sucrose utilization while SucA functions as one method of sucrose uptake in Caulobacter crescentus. This work sheds light on a new carbohydrate utilization locus in Caulobacter crescentus.

Sugar concentration in nectar: a quantitative metric of crop attractiveness for refined pollinator risk assessments.

Those involved with pollinator risk assessment know that agricultural crops vary in attractiveness to bees. Intuitively, this means that exposure to agricultural pesticides is likely greatest for attractive plants and lowest for unattractive plants. While crop attractiveness in the risk assessment process has been qualitatively remarked on by some authorities, absent is direction on how to refine the process with quantitative metrics of attractiveness. At a high level, attractiveness of crops to bees appears to depend on several key variables, including but not limited to: floral, olfactory, visual and tactile cues; seasonal availability; physical and behavioral characteristics of the bee; plant and nectar rewards. Notwithstanding the complexities and interactions among these variables, sugar content in nectar stands out as a suitable quantitative metric by which to refine pollinator risk assessments for attractiveness. Provided herein is a proposed way to use sugar nectar concentration to adjust the exposure parameter (with what is called a crop attractiveness factor) in the calculation of risk quotients in order to derive crop-specific tier I assessments. This Perspective is meant to invite discussion on incorporating such changes in the risk assessment process. © 2016 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

"I was born full deaf." Written language outcomes after 1 year of strategic and interactive writing instruction.

Nonstandard grammatical forms are often present in the writing of deaf students that are rarely, if ever, seen in the writing of hearing students. With the implementation of Strategic and Interactive Writing Instruction (SIWI) in previous studies, students have demonstrated significant gains in high-level writing skills (e.g., text structure) but have also made gains with English grammar skills. This 1-year study expands on prior research by longitudinally examining the written language growth (i.e., writing length, sentence complexity, sentence awareness, and function words) of 29 deaf middle-school students. A repeated-measures analysis of variance with a between-subjects variable for literacy achievement level was used to examine gains over time and the intervention's efficacy when used with students of various literacy levels. Students, whether high or low achieving, demonstrated statistically significant gains with writing length, sentence complexity, and sentence awareness. Subordinate clauses were found to be an area of difficulty, and follow up strategies are suggested. An analysis of function word data, specifically prepositions and articles, revealed different patterns of written language growth by language group (e.g., American Sign Language users, oral students, users of English-based sign).

The BAM complex subunit BamE (SmpA) is required for membrane integrity, stalk growth and normal levels of outer membrane {beta}-barrel proteins in Caulobacter crescentus.

The outer membrane of Gram-negative bacteria is an essential compartment containing a specific complement of lipids and proteins that constitute a protective, selective permeability barrier. Outer membrane beta-barrel proteins are assembled into the membrane by the essential hetero-oligomeric BAM complex, which contains the lipoprotein BamE. We have identified a homologue of BamE, encoded by CC1365, which is located in the outer membrane of the stalked alpha-proteobacterium Caulobacter crescentus. BamE associates with proteins whose homologues in other bacteria are known to participate in outer membrane protein assembly: BamA (CC1915), BamB (CC1653) and BamD (CC1984). Caulobacter cells lacking BamE grow slowly in rich medium and are hypersensitive to anionic detergents, some antibiotics and heat exposure, which suggest that the membrane integrity of the mutant is compromised. Membranes of the DeltabamE mutant have normal amounts of the outer membrane protein RsaF, a TolC homologue, but are deficient in CpaC*, an aggregated form of the outer membrane secretin for type IV pili. Delta bamE membranes also contain greatly reduced amounts of three TonB-dependent receptors that are abundant in wild-type cells. Cells lacking BamE have short stalks and are delayed in stalk outgrowth during the cell cycle. Based on these findings, we propose that Caulobacter BamE participates in the assembly of outer membrane beta-barrel proteins, including one or more substrates required for the initiation of stalk biogenesis.

Who's in charge here? Regulating cell cycle regulators.

Recent studies have illuminated key features of the transcriptional and signal transduction networks governing the cell division cycle of Caulobacter crescentus. These mechanisms generate oscillations in the activity of CtrA, a key regulator of DNA replication and transcription of cell cycle regulated genes. ctrA transcription is itself regulated as part of a cascade of transcriptional regulators, each of which drives the synthesis of proteins needed at different stages of the cell cycle. The CtrA protein is post-transcriptionally regulated by an extended network of two-component signaling proteins and by proteolysis. Proteins within these pathways are localized at opposite ends of the cell to generate two progenies in different stages of the cell cycle upon cell division.

Cooperative binding mode of the inhibitors of R6K replication, pi dimers.

The replication initiator protein, pi, plays an essential role in the initiation of plasmid R6K replication. Both monomers and dimers of pi bind to iterons in the gamma origin of plasmid R6K, yet monomers facilitate open complex formation, while dimers, the predominant form in the cell, do not. Consequently, pi monomers activate replication, while pi dimers inhibit replication. Recently, it was shown that the monomeric form of pi binds multiple tandem iterons in a strongly cooperative fashion, which might explain how monomers outcompete dimers for replication initiation when plasmid copy number and pi supply are low. Here, we examine cooperative binding of pi dimers and explore the role that these interactions may have in the inactivation of gamma origin. To examine pi dimer/iteron interactions in the absence of competing pi monomer/iteron interactions using wild-type pi, constructs were made with key base changes to each iteron that eliminate pi monomer binding yet have no impact on pi dimer binding. Our results indicate that, in the absence of pi monomers, pi dimers bind with greater cooperativity to alternate iterons than to adjacent iterons, thus preferentially leaving intervening iterons unbound and the origin unsaturated. We discuss new insights into plasmid replication control by pi dimers.

Mechanism of origin activation by monomers of R6K-encoded pi protein.

One recurring theme in plasmid duplication is the recognition of the origin of replication (ori) by specific Rep proteins that bind to DNA sequences called iterons. For plasmid R6K, this process involves a complex interplay between monomers and dimers of the Rep protein, pi, with seven tandem iterons of gamma ori. Remarkably, both pi monomers and pi dimers can bind to iterons, a new paradigm in replication control. Dimers, the predominant form in the cell, inhibit replication, while monomers facilitate open complex formation and activate the ori. Here, we investigate a mechanism by which pi monomers out-compete pi dimers for iteron binding, and in so doing activate the ori. With an in vivo plasmid incompatibility assay, we find that pi monomers bind cooperatively to two adjacent iterons. Cooperative binding is eliminated by insertion of a half-helical turn between two iterons but is diminished only slightly by insertion of a full helical turn between two iterons. These studies show also that pi bound to a consensus site promotes occupancy of an adjacent mutated site, another hallmark of cooperative interactions. pi monomer/iteron interactions were quantified using a monomer-biased pi variant in vitro with the same collection of two-iteron constructs. The cooperativity coefficients mirror the plasmid incompatibility results for each construct tested. pi dimer/iteron interactions were quantified with a dimer-biased mutant in vitro and it was found that pi dimers bind with negligible cooperativity to two tandem iterons.

Bacterial expression system with tightly regulated gene expression and plasmid copy number.

A new Escherichia coli host/vector system has been engineered to allow tight and uniform modulation of gene expression and gamma origin (ori) plasmid copy number. Regulation of gamma ori plasmid copy number is achieved through arabinose-inducible expression of the necessary Rep protein, pi, whose gene was integrated into the chromosome of the host strain under control of the P(BAD) promoter. gamma ori replication can be uniformly modulated over 100-fold by changing the concentration of l-arabinose in the growth medium. This strain avoids the problem of all-or-nothing induction of P(BAD) because it is deficient in both arabinose uptake and degradation genes. Arabinose enters the cell by a mutant LacY transporter, LacYA177C, which is expressed from the host chromosome. Although this strain could be compatible with any gamma ori plasmid, we describe the utility of a gamma ori expression vector that allows especially tight regulation of gene expression. With this host/vector system, it is possible to independently modulate gene expression and gene dosage, facilitating the cloning and overproduction of toxic gene products. We describe the successful use of this system for cloning a highly potent toxin, Colicin E3, in the absence of its cognate immunity protein. This system could be useful for cloning genes encoding other potent toxins, screening libraries for potential toxins, and maintaining any gamma ori vector at precise copy levels in a cell.