SPARK regulates AGC kinases central to the Toxoplasma gondii asexual cycle.

Apicomplexan parasites balance proliferation, persistence, and spread in their metazoan hosts. AGC kinases, such as PKG, PKA, and the PDK1 ortholog SPARK, integrate environmental signals to toggle parasites between replicative and motile life stages. Recent studies have cataloged pathways downstream of apicomplexan PKG and PKA; however, less is known about the global integration of AGC kinase signaling cascades. Here, conditional genetics coupled to unbiased proteomics demonstrates that SPARK complexes with an elongin-like protein to regulate the stability of PKA and PKG in the model apicomplexan Toxoplasma gondii. Defects attributed to SPARK depletion develop after PKG and PKA are down-regulated. Parasites lacking SPARK differentiate into the chronic form of infection, which may arise from reduced activity of a coccidian-specific PKA ortholog. This work delineates the signaling topology of AGC kinases that together control transitions within the asexual cycle of this important family of parasites.

Functionally uncoupled transcription-translation in Bacillus subtilis.

Tight coupling of transcription and translation is considered a defining feature of bacterial gene expression1,2. The pioneering ribosome can both physically associate and kinetically coordinate with RNA polymerase (RNAP)3-11, forming a signal-integration hub for co-transcriptional regulation that includes translation-based attenuation12,13 and RNA quality control2. However, it remains unclear whether transcription-translation coupling-together with its broad functional consequences-is indeed a fundamental characteristic of bacteria other than Escherichia coli. Here we show that RNAPs outpace pioneering ribosomes in the Gram-positive model bacterium Bacillus subtilis, and that this 'runaway transcription' creates alternative rules for both global RNA surveillance and translational control of nascent RNA. In particular, uncoupled RNAPs in B. subtilis explain the diminished role of Rho-dependent transcription termination, as well as the prevalence of mRNA leaders that use riboswitches and RNA-binding proteins. More broadly, we identified widespread genomic signatures of runaway transcription in distinct phyla across the bacterial domain. Our results show that coupled RNAP-ribosome movement is not a general hallmark of bacteria. Instead, translation-coupled transcription and runaway transcription constitute two principal modes of gene expression that determine genome-specific regulatory mechanisms in prokaryotes.

A second RNA-binding protein is essential for ethanol tolerance provided by the bacterial OLE ribonucleoprotein complex.

OLE (ornate, large, extremophilic) RNAs comprise a class of structured noncoding RNAs (ncRNAs) found in many extremophilic bacteria species. OLE RNAs constitute one of the longest and most widespread bacterial ncRNA classes whose major biochemical function remains unknown. In the Gram-positive alkaliphile Bacillus halodurans, OLE RNA is abundant, and localizes to the cell membrane by association with the transmembrane OLE-associated protein called OapA (formerly OAP). These characteristics, along with the well-conserved sequence and structural features of OLE RNAs, suggest that the OLE ribonucleoprotein (RNP) complex performs important biological functions. B. halodurans strains lacking OLE RNA (∆ole) or OapA (∆oapA) are less tolerant of cold (20 °C) and short-chain alcohols (e.g., ethanol). Here, we describe the effects of a mutant OapA (called PM1) that more strongly inhibits growth under cold or ethanol stress compared with strains lacking the oapA gene, even when wild-type OapA is present. This dominant-negative effect of PM1 is reversed by mutations that render OLE RNA nonfunctional. This finding demonstrates that the deleterious PM1 phenotype requires an intact RNP complex, and suggests that the complex has one or more additional undiscovered components. A genetic screen uncovered PM1 phenotype suppressor mutations in the ybzG gene, which codes for a putative RNA-binding protein of unknown biological function. We observe that YbzG protein (also called OapB) selectively binds OLE RNA in vitro, whereas a mutant version of the protein is not observed to bind OLE RNA. Thus, YbzG/OapB is an important component of the functional OLE RNP complex in B. halodurans.

Examining the impact of modality and learning style preferences on recall of psychiatric nursing and pharmacology terms.

The purpose of this experimental research study was to explore how modality and learning style preferences impact non-prescribing, first-year Licensed Vocational Nurse (LVN) students' recall of vocabulary. Independent t-test results indicated a statistically significant mean difference in short-term recall of pharmacological and psychiatric terms, with learners receiving visual text instruction recalling significantly more vocabulary than learners receiving audio text instruction. A correlation was not found between learning preferences and vocabulary recall.

Spelling patterns in preadolescents with atypical language skills: phonological, morphological, and orthographic factors.

Several investigations have considered the spelling abilities of children with reading disability; however, the spelling patterns of children with a language learning disability (LLD) have been largely ignored. This study examined the spelling error patterns of three groups of children who met strict inclusion criteria-those with a known LLD (n = 8), chronological-age-matched peers (CA; n = 8), and a younger spelling-age-matched group (SA; n = 8). An experimental spelling measure was specially designed and administered to elucidate the underlying linguistic features (clusters, digraphs, etc.) and linguistic classifications (phonological, orthographical, morphological) of misspellings. Based on inferential statistical analyses, a general pattern was that the LLD group and the SA group always differed from the CA group, whereas the LLD group performed similarly to the SA group. This finding lends credence to the hypothesis that children with an LLD, like children with reading disability, are delayed in spelling development rather than following a deviant developmental process. However, a qualitative analysis indicated two specific patterns. First, the LLD group had more trouble than did the SA group in representing the basic phonological structure of words, when complexity was increased by word length or linguistic structure. Second, in contrast to the SA group, the LLD group had greater omissions of inflected and derived morphological markers. These findings point to the critical role of morphology as the mediator between and form and meaning.