A pan-European epidemiological study reveals honey bee colony survival depends on beekeeper education and disease control

Reports of honey bee population decline has spurred many national efforts to understand the extent of the problem and to identify causative or associated factors. However, our collective understanding of the factors has been hampered by a lack of joined up trans-national effort. Moreover, the impacts of beekeeper knowledge and beekeeping management practices have often been overlooked, despite honey bees being a managed pollinator. Here, we established a standardised active monitoring network for 5 798 apiaries over two consecutive years to quantify honey bee colony mortality across 17 European countries. Our data demonstrate that overwinter losses ranged between 2% and 32%, and that high summer losses were likely to follow high winter losses. Multivariate Poisson regression models revealed that hobbyist beekeepers with small apiaries and little experience in beekeeping had double the winter mortality rate when compared to professional beekeepers. Furthermore, honey bees kept by professional beekeepers never showed signs of disease, unlike apiaries from hobbyist beekeepers that had symptoms of bacterial infection and heavy Varroa infestation. Our data highlight beekeeper background and apicultural practices as major drivers of honey bee colony losses. The benefits of conducting trans-national monitoring schemes and improving beekeeper training are discussed

Heterozygous <i>De Novo</i> and Inherited Mutations in the Smooth Muscle Actin (<i>ACTG2</i>) Gene Underlie Megacystis-Microcolon-Intestinal Hypoperistalsis Syndrome

<div><p>Megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS) is a rare disorder of enteric smooth muscle function affecting the intestine and bladder. Patients with this severe phenotype are dependent on total parenteral nutrition and urinary catheterization. The cause of this syndrome has remained a mystery since Berdon's initial description in 1976. No genes have been clearly linked to MMIHS. We used whole-exome sequencing for gene discovery followed by targeted Sanger sequencing in a cohort of patients with MMIHS and intestinal pseudo-obstruction. We identified heterozygous <i>ACTG2</i> missense variants in 15 unrelated subjects, ten being apparent <i>de novo</i> mutations. Ten unique variants were detected, of which six affected CpG dinucleotides and resulted in missense mutations at arginine residues, perhaps related to biased usage of CpG containing codons within actin genes. We also found some of the same heterozygous mutations that we observed as apparent <i>de novo</i> mutations in MMIHS segregating in families with intestinal pseudo-obstruction, suggesting that <i>ACTG2</i> is responsible for a spectrum of smooth muscle disease. <i>ACTG2</i> encodes γ2 enteric actin and is the first gene to be clearly associated with MMIHS, suggesting an important role for contractile proteins in enteric smooth muscle disease.</p></div

CpG dinucleotides within arginine codons are targets of <i>de novo</i> events in MMIHS.

<p>A.) The coding exons are shown with translation for the <i>ACTG2</i> gene. CpG dinucleotides are highlighted in red. Arginine residues in the protein are highlighted in green, and the mutations associated with <i>ACTG2</i> smooth muscle disease are aligned above the sequence. B.) The frequency of codon usage per 1000 codons for 6 arginine codons is shown. The human genome as a whole (bottom bar) is compared to all human actin genes including <i>ACTG2</i>.</p

<i>ACTG2</i> mutations affect conserved residues that are also targets for Mendelian disease.

<p>A.) Depiction of the mutations on the exons of the gene. Introns are not shown to scale. The mutations associated with MMIHS and intestinal pseudo-obstruction (orange) and those associated with intestinal pseudo-obstruction (green), including the previously reported mutation in one Finnish family are shown. A nonsense allele at position R63 was identified in our exome database associated with no clinical phenotype. The black, red, and blue lines under specific mutations highlight areas of multi-sequence alignment in boxes of corresponding colors in B. B.) Comparison of the mutations in MMIHS/intestinal pseudo-obstruction with disease causing mutations in other actin genes.</p

Clinical features and inheritance of <i>ACTG2</i> mutations in <i>de novo</i> and familial cases.

<p>Family pedigrees with clinical features correlated with the severity of smooth muscle dysfunction are shown. The most severe features of TPN dependence and megacystic bladder noted as dark squares within the upper quarters. The diagnosis of MMIHS (orange) was made in all but one subject with <i>de novo ACTG2</i> mutations. One subject (Fam 12-1) was diagnosed with gastrointestinal hollow visceral myopathy but had megacystis prenatally. Three families exhibiting dominant inheritance patterns are depicted below. One subject (Fam 13-1) suffered from a megacystic bladder but had later onset functional GI pseudo-obstruction. Another family (Fam19) is shown with two affected siblings with functional GI obstruction. Both carry a nonsynonymous mutation in alternate exon 4 of a predicted short <i>ACTG2</i> isoform (Uc010fex.1 indicated by *). Another family exhibited more extensive dominant inheritance (Fam34) consistent with familial visceral myopathy. Multiple paternal relatives suffer from episodes of gastrointestinal obstruction, constipation, gastrointestinal dysmotility, and bladder dysmotility segregating with the same mutation.</p

Exome analysis summary for six probands with MMIHS due to <i>ACTG2</i> mutations.

<p>Exome analysis summary for six probands with MMIHS due to <i>ACTG2</i> mutations.</p

Clinical characteristics of the patients with MMIHS due to <i>ACTG2 de novo</i> mutations.

<p>+ Feature present, − Feature absent,</p><p>*M- Metaclopramide, Cis- Cisapride, E-Erythromycin, (+) responsive, (−) non-responsive.</p

Characteristics of the <i>ACTG2</i> mutations in the MMIHS cohort.

a<p>Deduced cDNA change in transcript NM_001615 unless otherwise indicated.</p>b<p>Transcript Uc010fex.1.</p>c<p>Deduced amino acid substitution.</p>d<p>Presence of the observed mutation in other exomes from the Baylor Center for Mendelian Genomics cohort.</p

Natural history of patients with MMIHS due to <i>ACTG2 de novo</i> mutations.

<p>Natural history of patients with MMIHS due to <i>ACTG2 de novo</i> mutations.</p