Behavioral plasticity in honey bees is associated with differences in brain microRNA transcriptome.

Small, non-coding microRNAs (miRNAs) have been implicated in many biological processes, including the development of the nervous system. However, the roles of miRNAs in natural behavioral and neuronal plasticity are not well understood. To help address this we characterized the microRNA transcriptome in the adult worker honey bee head and investigated whether changes in microRNA expression levels in the brain are associated with division of labor among honey bees, a well-established model for socially regulated behavior. We determined that several miRNAs were downregulated in bees that specialize on brood care (nurses) relative to foragers. Additional experiments showed that this downregulation is dependent upon social context; it only occurred when nurse bees were in colonies that also contained foragers. Analyses of conservation patterns of brain-expressed miRNAs across Hymenoptera suggest a role for certain miRNAs in the evolution of the Aculeata, which includes all the eusocial hymenopteran species. Our results support the intriguing hypothesis that miRNAs are important regulators of social behavior at both developmental and evolutionary time scales.

A unique haplotype of the apolipoprotein B-100 allele associated with familial defective apolipoprotein B-100 in a Chinese man discovered during a study of the prevalence of this disorder.

The prevalence of familial defective apolipoprotein (apo) B-100 (FDB) was determined by sampling 5,160 volunteer subjects from among 14,058 eligible employees of a bank in California. The sample was ethnically diverse (44.6% of the population was non-Caucasian). The prevalence of FDB in the study population was 0.08% with a 90% confidence interval of 0.01-0.14%. Four subjects were found to have the apoB 3500 codon mutation by mutagenic polymerase chain reaction, which creates an MspI site at the 3500 codon of normal alleles but not alleles coding for the Arg-->Gln mutation of FDB. Three of these were Caucasian and born in North America. The fourth was a native of China. Haplotype analysis of the affected allele of the Chinese subject using 10 markers described by Ludwig and McCarthy (1990. Am. J. Hum. Genet. 47: 712-720) revealed a unique haplotype that differed from the haplotype of all other subjects with FDB. This unique allele had 30 repeats of a 3' hypervariable element instead of 48 as was found in the allele associated with FDB in other subjects, and in the 3' region there was an EcoRI site that was also not present in the allele most commonly found in association with FDB. We conclude that the prevalence of FDB in our ethnically diverse population is lower than that reported in previous studies of predominantly Caucasian populations and that the Chinese subject represents either an independent mutation or possibly recombination at the 3' end of the apoB gene, an event not previously described.

Hypolipidemic effects of nicotinic acid in patients with familial defective apolipoprotein B-100.

Familial defective apolipoprotein B-100 (FDB) is a dominantly inherited disorder associated with hypercholesterolemia, in which an amino acid substitution in apolipoprotein B-100 results in low-density lipoprotein (LDL) particles that bind poorly to the LDL receptor and accumulate in plasma. Patients with FDB described to date have been heterozygous for this disorder, and their plasma contains both normal and defective-binding LDL particles. We have evaluated the hypocholesterolemic effects of nicotinic acid (3 g/d) in four patients with FDB, and compared the response to that of nine patients with heterozygous familial hypercholesterolemia (FH). Concentrations of LDL decreased by 24% in patients with FDB and by 14% in patients with FH. These results support the view that drugs which reduce LDL synthesis may be particularly effective in the treatment of patients with FDB.