Comparative genome analysis of two Spiroplasma melliferum isolates

Figure 4 from Lo et al., 2013.  (Open Access)

About 1 year following the publication of a genome assembly for Spiroplasma melliferum KC3 by Dmitry Alexeev and colleagues comes an assembly from S. melliferum isolate IPMB4A by Wen-Sui Lo and colleagues. 

The papers:

Alexeev et al., 2012. Application of Spiroplasma melliferum proteogenomic profiling for the discovery of virulence factors and pathogenicity mechanisms in host-associated sprioplasmas. J. Proteome Res. 11(1), pp224-236.

 Wen-Sui Lo, L. Chen, W. Chung, G. Gasparich and C. Kuo. 2013. Comparative genome analysis of Spiroplasma melliferum IPMB4A, a honeybee-associated bacterium. BMC Genomics, 14:22.

Elroy the Bee Dog

Another Bee Dog to introduce!

This is Elroy, a springer spaniel trained by Martin Dominick in Australia to sniff out honey bee hives with American Foulbrood (AFB) disease.

Image from the Australian Government RIRDC.

Like Klinker the black lab from the Maryland Dept. of Agriculture, mentioned in an earlier post, Elroy is employed to seek out any honey bee colony that is infected with the AFB bacteria Paenibacillus larvae.  These bee dogs are able to do this work much faster and arguably more effectively than bee keepers (no offense intended to bee keepers).  Elroy even had a bee suit made especially for him so he could work at anytime and not worry about stings.  That's pretty darn cute.

Images of the article written about Elroy back in 2011 by the Australian Government Rural Industries Research and Development Corporation:

Taxonomic description of a Betaproteobacteria and a Gammaproteobacteria-1 from the honey bee gut

Nancy Moran's lab has worked with these two honey bee gut bugs previously, producing several prior publications.  A recent paper in the International Journal of Systemic and Evolutionary Microbiology by Waldan Kwong and Nancy Moran is important, however, as it provides the official and exhaustive work necessary to formally denominate these two new species.  It's also cool because they came up with some fun and worthy names for them!

The Beta, Snodgrassella alvi, is named after the American entomologist Robert Evans Snodgrass (1875-1962) whose numerous authorships include "The Anatomy of the Honeybee".  The specific epithet, alvi, is Latin for 'gut of bees'.  S. alvi was isolated not only from honey bees (Apis mellifera) but also from bumblebees (Bombus bimaculatus and Bombus vagrans).

The Gamma-1, Gilliamella apicola, is named in honor of the American microbiologist Martha A. Gilliam, who has worked extensively with the honey bee microbiota with interest in how these microbes can protect bees from harmful pathogens.  'Bee-dweller' is the translated Latin for the specific epithet apicola.  G. apicola was isolated not only from honey bees (Apis mellifera) but also from bumblebees (Bombus bimaculatus and Bombus vagrans).  In addition, Kwong and Moran determined that G. apicola-like bacteria also occur in a number of other bee species by analyzing previously identified bacteria sequences isolated from the Asian and giant honey bees (Apis cerana and Apis dorsata) and additional bumblebees (Bombus terrestris and Bombus impatiens).  As if describing the type species for this new genus wasn't enough, G. apicola belongs to a new Order (Orbales) and Family (Orbaceae), also described here by Kwong and Moran!

There is substantial genetic diversity in these groups, with isolates from the same bee host species more closely related to one another than to similar bacteria from other bee species.  This may be due to a close evolutionary history between bee host and their specific bacteria strain.  Thus, distinct Gilliamella and Snodgrassella species are likely to be discerned in future research.  

A link to the article published in the International Journal of Systemic and Evolutionary Microbiology is here:  Kwong and Moran, 2012

Cultivation and characterization of the gut symbionts of honey bees and bumble bees: Snodgrassella alvi gen. nov., sp. nov., a member of the Neisseriaceae family of the Betaproteobacteria; and Gilliamella apicola gen. nov., sp. nov., a member of Orbaceae fam. nov., Orbales ord. nov., a sister taxon to the Enterobacteriales order of the Gammaproteobacteria

1. Waldan K. Kwong and
2. Nancy A. Moran

1. Yale University

Dogs sniff out pathogenic bacteria in honey bee colonies

I'm a big fan of canines, and here is my favorite example of how to look for bee bugs.  This is William Troup and Klinker, working for the Maryland Department of Agriculture inspecting honey bee colonies.  Klinker, a black lab, was scent trained on American foul brood (AFB; Paenibacillus larvae), a pathogenic bacteria of European honey bee larvae that create a very distinct smell when present.

Picture from the Maryland Dept. of Agriculture

Once scent trained, dogs can be used to quickly assess colonies for any scent of the bacteria.  Having such a sensitive sense of smell, dogs can detect AFB even at low levels.  This prevents cracking open a hive and pulling out frames one by one to assess them for signs of AFB, particularly beneficial in early Spring when it still may be quite cold out and the girls need to keep in warmth for the developing brood.

If anyone knows of additional dog nose work training in other states/countries to detect pathogens or has updates on Klinker and William Troup at the MDA, please share the knowledge and post a comment.  I'd love to learn more about this.

A link to the MDA Apiary Inspection site is here:  http://mda2.maryland.gov/plants-pests/Pages/apiary_inspection.aspx

The genome of Paenibacillus alvei

Researchers from Georg-August University Göttingen Germany have completed the genomic sequence of P. alvei isolate DSM 29 (6.83Mb)  This is an aerobic, Gram-positive bacteria that is often associated with Melissococcus plutonius, the bacterial causative agent of European foul brood disease in honey bees.

Paenibacillus alvei are the larger, elongated bacteria.  Melissococcus plutonius bacteria are clustered in the center.  Photo from the USDA/ARS.

Along with P. alvei, a number of other bacteria also seem to associate frequently with M. plutonius infections including Brevibacillus laterosporus and Enterococcus faecalis.  Of note from the genome are a number of chitinase genes (10) and a hyaluronate lyase homolog, each of which may be virulence factors involved in host cell invasion.  Also, a unique antimicrobial gene and several encoded toxin molecules (binary, mosquitocidal, alveolysin, insecticidal toxin complex) were identified.  454 GS-FLX with Titanium XL was used to sequence paired-end and shotgun DNA libraries, assembled to 18x coverage in 25 contigs.  The genome contains approximately 6,605 coding genes.

A link to the paper in the Journal of Bacteriology is here:
P. alvei genome by Djukic, Becker, Poehlein, Voget, and Daniel

American Bee Research Conference 2013

The annual American Bee Research Conference is a honey bee-centric meeting of bee keepers and researchers being held this week in Hershey, Pennsylvania alongside the somewhat more popular North American Beekeeping Conference.  Bee bug topics are on schedule to be presented, and are linked here:

https://docs.google.com/file/d/0B4dGydUTgVgRZVc5S1AzZUVnUTg/edit


Pollen mites

While not of concern to honey bees, pollen mite (Chaetodactyllus) infestations can be of concern to other bee species, particularly blue orchard bees (Osmia lignaria) and other Osmia species (mason bees, Japanese hornfaced bee, etc.) of the family Megachilidae.  The Krombein's hairy-footed mite (Chaetodactyllus krombeini) is a pollen mite native to North America.  Additional species of Chaetodactyllus occur on other parts of the globe, more commonly in humid rather than arid regions.

When they infest brood cells, they will kill and then feed on bee eggs and larvae.  They will also feed on pollen stores, hence the common name.  Reproduction in the cell can produce a shocking mass of mites: 

USDA/ARS image of C. krombeini mites in a blue orchard bee brood cell.

Emerging adult bees from other cells in the nest can become covered with the mites, and give them a lift to new frontiers.  Some mites may also stay behind in the nest and parasitize a new female bee looking into using the abandoned nest.

Here is a link to a good description of the pollen mite, Chaetodactylus krombeini, from the North American Bee Mite Project at the University of Michigan: Species_Accounts/Chaetodactylus_krombeini.htm.  The second image is from the USDA/ARS.

A recent paper "Distribution of Chaetodactyllus krombeini (Acari: Chaetodactylidae) within Osmia cornifrons (Hymenoptera: Megachilidae) nests: implications for population management" by Matthew McKinney and Yong-Lak Park is here:  http://link.springer.com/article/10.1007/s10493-012-9629-7

Abstract

Chaetodactylus krombeini (Baker) (Acari: Chaetodactylidae) is a cleptoparasitic mite that negatively affects propagation of Osmia spp. (Hymenoptera: Megachilidae) for orchard pollination in the USA. This study was conducted to determine the effect of C. krombeini on mortality of male and female Osmia cornifrons, the Japanese hornfaced bee. A total of 107 O. cornifrons nests were examined to determine within-nest distribution of C. krombeini with regression analyses. A total of 30 mite-free O. cornifrons nests were observed and within-nest distribution of male and female O. cornifrons was determined with non-linear regression analyses. In addition, cocoons from 20 mite-infested O. cornifrons cells were examined to determine whether C. krombeini could be found inside cocoons of O. cornifrons. The results of this study showed that female O. cornifrons and C. krombeini were found more frequently in the inner part of the nest, and male O. cornifrons were found mostly in the center of the nest. No C. krombeini were found inside O. cornifrons cocoons. These results indicate that C. krombeini have a greater negative impact on mortality in the egg and larval stages of female O. cornifrons than in male O. cornifrons. Implications for management of C. krombeini and O. cornifrons populations for orchard pollination are discussed in this article.

The spread of antibiotic resistance genes due to pressure asserted by prolific antibiotic exposure in animals, in this case honey bees.

Antibiotics (oxytetracycline in this case) affect not only targeted pathogens like foul brood bacteria (Paenibacillus and Melissococcus) but also non-targeted endosymbiotic gut flora.  The latest from Nancy Moran's lab.  :

Long-Term Exposure to Antibiotics Has Caused Accumulation of Resistance Determinants in the Gut Microbiota of Honeybees

1. Baoyu Tian^a*, 
2. Nibal H. Fadhil^a, 
3. J. Elijah Powell^a, 
4. Waldan K. Kwong^a, and
5. Nancy A. Moran

http://mbio.asm.org/content/3/6/e00377-12

ABSTRACT

Antibiotic treatment can impact nontarget microbes, enriching the pool of resistance genes available to pathogens and altering community profiles of microbes beneficial to hosts. The gut microbiota of adult honeybees, a distinctive community dominated by eight bacterial species, provides an opportunity to examine evolutionary responses to long-term treatment with a single antibiotic. For decades, American beekeepers have routinely treated colonies with oxytetracycline for control of larval pathogens. Using a functional metagenomic screen of bacteria from Maryland bees, we detected a high incidence of tetracycline/oxytetracycline resistance. This resistance is attributable to known resistance loci for which nucleotide sequences and flanking mobility genes were nearly identical to those from human pathogens and from bacteria associated with farm animals. Surveys using diagnostic PCR and sequencing revealed that gut bacteria of honeybees from diverse localities in the United States harbor eight tetracycline resistance loci, including efflux pump genes (tetB, tetC, tetD, tetH,tetL, and tetY) and ribosome protection genes (tetM and tetW), often at high frequencies. Isolates of gut bacteria from Connecticut bees display high levels of tetracycline resistance. Resistance genes were ubiquitous in American samples, though rare in colonies unexposed for 25 years. In contrast, only three resistance loci, at low frequencies, occurred in samples from countries not using antibiotics in beekeeping and samples from wild bumblebees. Thus, long-term antibiotic treatment has caused the bee gut microbiota to accumulate resistance genes, drawn from a widespread pool of highly mobile loci characterized from pathogens and agricultural sites.

IMPORTANCE We found that 50 years of using antibiotics in beekeeping in the United States has resulted in extensive tetracycline resistance in the gut microbiota. These bacteria, which form a distinctive community present in healthy honeybees worldwide, may function in protecting bees from disease and in providing nutrition. In countries that do not use antibiotics in beekeeping, bee gut bacteria contained far fewer resistance genes. The tetracycline resistance that we observed in American samples reflects the capture of mobile resistance genes closely related to those known from human pathogens and agricultural sites. Thus, long-term treatment to control a specific pathogen resulted in the accumulation of a stockpile of resistance capabilities in the microbiota of a healthy gut. This stockpile can, in turn, provide a source of resistance genes for pathogens themselves. The use of novel antibiotics in beekeeping may disrupt bee health, adding to the threats faced by these pollinators.

Previous SectionNext Section