Genetically engineered rpsL merodiploidy impacts secondary metabolism and antibiotic resistance in Streptomyces.

Certain point mutations within gene for ribosomal protein S12, rpsL, are known to dramatically change physiological traits of bacteria, most prominently antibiotic resistance and production of various metabolites. The rpsL mutants are usually searched among spontaneous mutants resistant to aminoglycoside antibiotics, such as streptomycin or paromomycin. The shortcomings of traditional selection are as follows: random rpsL mutants may carry undesired genome alterations; many rpsL mutations cannot be isolated because they are either not associated with increased antibiotic resistance or non-viable in the absence of intact rpsLWT gene. Introduction of mutant rpsL alleles in the rpsLWT background can be used to circumvent these obstacles. Here we take the latter approach and report the generation and properties of a set of stable rpsL merodiploids for Streptomyces albus J1074. We identified several rpsL alleles that enhance endogenous and heterologous antibiotic production by this strain and show that rpsLWTrpsLK88E merodiploid displays increased streptomycin resistance. We further tested several promising rpsL alleles in two more strains, Streptomyces cyanogenus S136 and Streptomyces ghanaensis ATCC14672. In S136, plasmid-borne rpsLK88E+P91S and rpsLK88R led to elevated landomycin production; no changes were detected for ATCC14672 merodiploids. Our data outline the prospects for and limitations to rpsL merodiploids as a tool for rapid enhancement of secondary metabolism in Streptomyces.

The spectrum of epilepsy in children with 15q13.3 microdeletion syndrome.

PURPOSE: To further define the epilepsy phenotype in a cohort of children with 15q13.3 microdeletion syndrome. METHODS: We retrospectively reviewed the phenotypic spectrum of all children aged < 18 years with epilepsy and 15q13.3 microdeletion syndrome. RESULTS: Thirteen children were included, 69% were female. The median age of children in the cohort was 12 years (age range: 3 years-15 years). Median age at seizure onset was 4 years. Eleven children (85%) had intellectual disability. Nine of 13 children (69%) had a history of typical absence seizures with median age of onset at 5 years (2 had absence status epilepticus). Thirty-one percent (4/13) had focal with impaired awareness non-motor onset seizures. ILAE recognized absence epilepsy syndromes were diagnosed in 6/13 (46%). The remainder were classified as having genetic generalized epilepsies with overlap clinical features, combined or focal epilepsies. Electroencephalogram in the cohort showed generalized (85%) and focal epileptiform discharges (62%) and posterior dominant rhythm slowing (33%). One child had electrical status epilepticus of sleep. Neuroimaging was performed in 5 children (38%) and revealed abnormal findings in 3. Seizures were drug resistant in a third of the cohort. Valproate resulted in seizure freedom in 5 (42%). Oxcarbazepine caused clinical worsening in one child with combined seizure types. Two children tried cannabidiol and one tried the ketogenic diet; neither was effective. CONCLUSIONS: The epilepsy phenotype in children with 15q13.3 microdeletion syndrome is defined by childhood onset absence seizures, and may have atypical features such as, early onset absences, persistence into adolescence, status epilepticus, intellectual disability and treatment resistance. Focal seizures and focal EEG findings may be observed and should be treated cautiously, given the possibility of combined seizure types. Valproate appeared effective, although other treatments must be explored further.

The McMaster Pediatric Migraine Questionnaire: a prospective validation study.

OBJECTIVE: Migraine affects approximately 4%-11% of elementary school children; yet reaching a diagnosis in this age group can be challenging. The goal of this study was to develop a screening migraine questionnaire that could be easily implemented by a general pediatrician and validate its use in diagnosing migraine in children 5-12 years old. METHODS: A questionnaire, the McMaster Migraine Tool, was developed using the International Classification of Headache Disorders-II criteria for migraine. The validity of the questionnaire was assessed by comparing the diagnosis based on the results of the questionnaire compared with the diagnosis made by a pediatric neurologist. RESULTS: The questionnaire was used to assess a cohort of 69 children referred to the Pediatric Neurology Clinic for headache. The sensitivity and specificity of the McMaster Migraine Tool were determined to be 84% and 69%, respectively. Families graded its ease of use to be 9 of 10 (10 being easy to use). CONCLUSION: The McMaster Migraine Tool may be useful in diagnosing migraine in 5-12-year-old children, as it is readily completed and regarded as easy to use. Application of this tool could lead to expedited diagnosis and management of migraine.