The Draft Genome of the Invasive Walking Stick, Medauroidea extradendata, Reveals Extensive Lineage-Specific Gene Family Expansions of Cell Wall Degrading Enzymes in Phasmatodea.

Plant cell wall components are the most abundant macromolecules on Earth. The study of the breakdown of these molecules is thus a central question in biology. Surprisingly, plant cell wall breakdown by herbivores is relatively poorly understood, as nearly all early work focused on the mechanisms used by symbiotic microbes to breakdown plant cell walls in insects such as termites. Recently, however, it has been shown that many organisms make endogenous cellulases. Insects, and other arthropods, in particular have been shown to express a variety of plant cell wall degrading enzymes in many gene families with the ability to break down all the major components of the plant cell wall. Here we report the genome of a walking stick, Medauroidea extradentata, an obligate herbivore that makes uses of endogenously produced plant cell wall degrading enzymes. We present a draft of the 3.3Gbp genome along with an official gene set that contains a diversity of plant cell wall degrading enzymes. We show that at least one of the major families of plant cell wall degrading enzymes, the pectinases, have undergone a striking lineage-specific gene family expansion in the Phasmatodea. This genome will be a useful resource for comparative evolutionary studies with herbivores in many other clades and will help elucidate the mechanisms by which metazoans breakdown plant cell wall components

Forager bees (Apis mellifera) highly express immune and detoxification genes in tissues associated with nectar processing.

Pollinators, including honey bees, routinely encounter potentially harmful microorganisms and phytochemicals during foraging. However, the mechanisms by which honey bees manage these potential threats are poorly understood. In this study, we examine the expression of antimicrobial, immune and detoxification genes in Apis mellifera and compare between forager and nurse bees using tissue-specific RNA-seq and qPCR. Our analysis revealed extensive tissue-specific expression of antimicrobial, immune signaling, and detoxification genes. Variation in gene expression between worker stages was pronounced in the mandibular and hypopharyngeal gland (HPG), where foragers were enriched in transcripts that encode antimicrobial peptides (AMPs) and immune response. Additionally, forager HPGs and mandibular glands were enriched in transcripts encoding detoxification enzymes, including some associated with xenobiotic metabolism. Using qPCR on an independent dataset, we verified differential expression of three AMP and three P450 genes between foragers and nurses. High expression of AMP genes in nectar-processing tissues suggests that these peptides may contribute to antimicrobial properties of honey or to honey bee defense against environmentally-acquired microorganisms. Together, these results suggest that worker role and tissue-specific expression of AMPs, and immune and detoxification enzymes may contribute to defense against microorganisms and xenobiotic compounds acquired while foraging

Diagnosing Prince Myshkin

The article presents literary criticism of the book \u22The Idiot\u22 by Fyodor Dostoyevsky. It focuses on the medical history of the character Prince Myshkin. According to the author, Myshkin\u27s diagnosis of and treatment for epilepsy play an important role in his character and in the plot of the novel. Topics discussed include recognition, Dostoyevsky\u27s medical knowledge, and the 19th-century medical concept of idiotism

Intersecting Nervous Disorders in Dostoevsky’s

Intersecting Nervous Disordersin Dostoevsky’

Nestmate recognition in social insects: overcoming physiological constraints with collective decision making.

Social insects rank among the most abundant and influential terrestrial organisms. The key to their success is their ability to form tightly knit social groups that perform work cooperatively, and effectively exclude non-members from the colony. An extensive body of research, both empirical and theoretical, has explored how optimal acceptance thresholds could evolve in individuals, driven by the twin costs of inappropriately rejecting true nestmates and erroneously accepting individuals from foreign colonies. Here, in contrast, we use agent-based modeling to show that strong nestmate recognition by individuals is often unnecessary. Instead, highly effective nestmate recognition can arise as a colony-level property from a collective of individually poor recognizers. Essentially, although an intruder can get by one defender when their odor cues are similar, it is nearly impossible to get past many defenders if there is the slightest difference in cues. The results of our models match observed rejection rates in studies of ants, wasps, and bees. We also show that previous research in support of the optimal threshold theory approach to the problem of nestmate recognition can be alternatively viewed as evidence in favor of the collective formation of a selectively permeable barrier that allows in nestmates (at a significant cost) while rejecting non-nestmates. Finally, this work shows that nestmate recognition has a stronger task allocation component than previously thought, as colonies can nearly always achieve perfect nestmate recognition if it is cost effective for them to do so at the colony level. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00265-010-1094-x) contains supplementary material, which is available to authorized users

Continuity properties of vectors realizing points in the classical field of values

For an $n$-by-$n$ matrix $A$, let $f_A$ be its "field of values generating function" defined as $f_A\colon x\mapsto x^*Ax$. We consider two natural versions of the continuity, which we call strong and weak, of $f_A^{-1}$ (which is of course multi-valued) on the field of values $F(A)$. The strong continuity holds, in particular, on the interior of $F(A)$, and at such points $z \in \partial F(A)$ which are either corner points, belong to the relative interior of flat portions of $\partial F(A)$, or whose preimage under $f_A$ is contained in a one-dimensional set. Consequently, $f_A^{-1}$ is continuous in this sense on the whole $F(A)$ for all normal, 2-by-2, and unitarily irreducible 3-by-3 matrices. Nevertheless, we show by example that the strong continuity of $f_A^{-1}$ fails at certain points of $\partial F(A)$ for some (unitarily reducible) 3-by-3 and (unitarily irreducible) 4-by-4 matrices. The weak continuity, in its turn, fails for some unitarily reducible 4-by-4 and untiarily irreducible 6-by-6 matrices.Comment: 9 pages, 2 figures. Linear and Multilinear Algebra 201

Taxonomically restricted genes are associated with the evolution of sociality in the honey bee

<p>Abstract</p> <p>Background</p> <p>Studies have shown that taxonomically restricted genes are significant in number and important for the evolution of lineage specific traits. Social insects have gained many novel morphological and behavioral traits relative to their solitary ancestors. The task repertoire of an advanced social insect, for example, can be 40-50 tasks, about twice that of a solitary wasp or bee. The genetic basis of this expansion in behavioral repertoire is still poorly understood, and a role for taxonomically restricted genes has not been explored at the whole genome level.</p> <p>Results</p> <p>Here we present comparative genomics results suggesting that taxonomically restricted genes may have played an important role in generating the expansion of behavioral repertoire associated with the evolution of eusociality. First, we show that the current honey bee official gene set contains about 700 taxonomically restricted genes. These are split between orphans, genes found only in the Hymenoptera, and genes found only in insects. Few of the orphans or genes restricted to the Hymenoptera have been the focus of experimental work, but several of those that have are associated with novel eusocial traits or traits thought to have changed radically as a consequence of eusociality. Second, we predicted that if taxonomically restricted genes are important for generating novel eusocial traits, then they should be expressed with greater frequency in workers relative to the queen, as the workers exhibit most of the novel behavior of the honey bee relative to their solitary ancestors. We found support for this prediction. Twice as many taxonomically restricted genes were found amongst the genes with higher expression in workers compared to those with higher expression in queens. Finally, we compiled an extensive list of candidate taxonomically restricted genes involved in eusocial evolution by analyzing several caste specific gene expression data sets.</p> <p>Conclusions</p> <p>This work identifies a large number of candidate taxonomically restricted genes that may have played a role in eusocial evolution. This work thus lays the foundation for future functional genomics work on the evolution of novelty in the context of social behavior. We also present preliminary evidence, based on biased patterns of gene expression, that taxonomically restricted genes may have played a role in the evolution of caste systems, a characteristic lineage specific social trait.</p