The Microbiome in Light of Host Evolution

Recent advances in sequencing technologies have provided an unprecedented window in the unseen biological world. Accompanying this revolution is a growing appreciation for the ubiquity and diversity of beneficial interactions between animals and the microbes they carry. Given the symbiotic roles of microbes in host nutrition, immunity, behavior, development, and nearly every other facet of host biology, it is becoming increasingly clear that any understanding of hosts and their evolution would be incomplete without also considering the microbial dimension. Yet despite the growing body of evidence that many of these partnerships are rooted deep in evolutionary time, the majority of studies have tended to focus on how the composition of the present-day microbiome is shaped by present-day factors. In order to place the microbiome in the larger context of host biology, a more complete understanding of the evolutionary interplay between hosts and their microbial associates is needed. Here, I use Odontotaenius disjunctus, a large xylophagous beetle found throughout eastern North America, to explore how its present-day gut microbiome has both shaped and been shaped by evolutionary processes that have acted on the host. First, I show that recent evolution in O. disjunctus reflects the influence of Pleistocene glaciation on the host’s demographic history. Next, I show that the present-day gut microbiome of O. disjunctus reflects both the influence of this recent host evolution and the more ancient influence of natural selection that has acted on the host to maintain these beneficial partnerships over a much longer timescale. Finally, I show that the persistence of certain members of the gut microbiome over evolutionary time may be explained by their role in host lignocellulose digestion. My findings demonstrate that, much like host genomes, the microbiome has been, is being, and will continue to be shaped simultaneously by forces of selection and neutrality along the arc of evolutionary history shared by these intimate partners

Wikipedia as an encyclopaedia of life

In his 2003 essay E O Wilson outlined his vision for an “encyclopaedia of life” comprising “an electronic page for each species of organism on Earth”, each page containing “the scientific name of the species, a pictorial or genomic presentation of the primary type specimen on which its name is based, and a summary of its diagnostic traits.” Although the “quiet revolution” in biodiversity informatics has generated numerous online resources, including some directly inspired by Wilson's essay (e.g., "http://ispecies.org":http://ispecies.org, "http://www.eol.org":http://www.eol.org), we are still some way from the goal of having available online all relevant information about a species, such as its taxonomy, evolutionary history, genomics, morphology, ecology, and behaviour. While the biodiversity community has been developing a plethora of databases, some with overlapping goals and duplicated content, Wikipedia has been slowly growing to the point where it now has over 100,000 pages on biological taxa. My goal in this essay is to explore the idea that, largely independent of the efforts of biodiversity informatics and well-funded international efforts, Wikipedia ("http://en.wikipedia.org/wiki/Main_Page":http://en.wikipedia.org/wiki/Main_Page) has emerged as potentially the best platform for fulfilling E O Wilson’s vision

Competition-based model of pheromone component ratio detection in the moth

For some moth species, especially those closely interrelated and sympatric, recognizing a specific pheromone component concentration ratio is essential for males to successfully locate conspecific females. We propose and determine the properties of a minimalist competition-based feed-forward neuronal model capable of detecting a certain ratio of pheromone components independently of overall concentration. This model represents an elementary recognition unit for the ratio of binary mixtures which we propose is entirely contained in the macroglomerular complex (MGC) of the male moth. A set of such units, along with projection neurons (PNs), can provide the input to higher brain centres. We found that (1) accuracy is mainly achieved by maintaining a certain ratio of connection strengths between olfactory receptor neurons (ORN) and local neurons (LN), much less by properties of the interconnections between the competing LNs proper. An exception to this rule is that it is beneficial if connections between generalist LNs (i.e. excited by either pheromone component) and specialist LNs (i.e. excited by one component only) have the same strength as the reciprocal specialist to generalist connections. (2) successful ratio recognition is achieved using latency-to-first-spike in the LN populations which, in contrast to expectations with a population rate code, leads to a broadening of responses for higher overall concentrations consistent with experimental observations. (3) when longer durations of the competition between LNs were observed it did not lead to higher recognition accuracy

Body composition in male elite athletes, comparison of bioelectrical impedance spectroscopy with dual energy X-ray absorptiometry

<p>Abstract</p> <p>Background</p> <p>The aim of this study was to compare body composition results from bioelectrical spectroscopy (BIS) with results from dual energy X-ray absorptiometry (DXA) in a population of male elite athletes. Body composition was assessed using DXA (Lunar Prodigy, GE Lunar Corp., Madison, USA) and BIS (Hydra 4200, Xitron Technologies Inc, San Diego, California, USA) at the same occasion. Agreement between methods was assessed using paired t-tests and agreement-plots.</p> <p>Results</p> <p>Thirty-three male elite athletes (soccer and ice hockey) were included in the study. The results showed that BIS underestimates the proportion of fat mass by 4.6% points in the ice hockey players. In soccer players the BIS resulted in a lower mean fat mass by 1.1% points. Agreement between the methods at the individual level was highly variable.</p> <p>Conclusion</p> <p>Body composition results assessed by BIS in elite athletes should be interpreted with caution, especially in individual subjects. BIS may present values of fat mass that is either higher or lower than fat mass assessed by DXA, independent of true fat content of the individual.</p

1940: Abilene Christian College Bible Lectures - Full Text

Delivered in the Auditorium of Abilene Christian College, February, 1940, Abilene, Texas. Published April, 1940 PRICE, $1.00 FIRM FOUNDATION PUBLISHING HOUSE Austin, Texas

Oral health of Chinese people with systemic sclerosis

The aim was to study oral health status, salivary function, and oral features of Chinese people with Systemic Sclerosis (SSc). Chinese people with SSc attending a university specialist clinic were invited for a questionnaire survey and a clinical examination. Ethics approval was sought (UW 08-305). Gender- and age-matched individuals without SSc who attended a university dental hospital were recruited for comparison. Forty-two SSc patients with a mean age of 54.0 ± 12.2 were examined. This study found no Chinese people with systemic sclerosis were periodontally healthy and many (76%) had periodontal pockets despite most of them (93%) practiced daily tooth-brushing. They all had caries experience (DMFT = 10.5) and many (65%) had untreated decay. Mucosal telangiectasia was a common oral feature (80%). They had lower resting salivary flow rates (0.18 ± 0.17 ml/min vs. 0.31 ± 0.21 ml/min; p = 0.003) and pH values (6.90 ± 0.40 vs. 7.28 ± 0.31; p < 0.001) and reduced maximal mouth opening (40.1 ± 6.5 mm vs. 43.6 ± 7.0 mm) than people without SSc

The role of conversation in health care interventions: enabling sensemaking and learning

<p>Abstract</p> <p>Background</p> <p>Those attempting to implement changes in health care settings often find that intervention efforts do not progress as expected. Unexpected outcomes are often attributed to variation and/or error in implementation processes. We argue that some unanticipated variation in intervention outcomes arises because unexpected conversations emerge during intervention attempts. The purpose of this paper is to discuss the role of conversation in shaping interventions and to explain why conversation is important in intervention efforts in health care organizations. We draw on literature from sociolinguistics and complex adaptive systems theory to create an interpretive framework and develop our theory. We use insights from a fourteen-year program of research, including both descriptive and intervention studies undertaken to understand and assist primary care practices in making sustainable changes. We enfold these literatures and these insights to articulate a common failure of overlooking the role of conversation in intervention success, and to develop a theoretical argument for the importance of paying attention to the role of conversation in health care interventions.</p> <p>Discussion</p> <p>Conversation between organizational members plays an important role in the success of interventions aimed at improving health care delivery. Conversation can facilitate intervention success because interventions often rely on new sensemaking and learning, and these are accomplished through conversation. Conversely, conversation can block the success of an intervention by inhibiting sensemaking and learning. Furthermore, the existing relationship contexts of an organization can influence these conversational possibilities. We argue that the likelihood of intervention success will increase if the role of conversation is considered in the intervention process.</p> <p>Summary</p> <p>The generation of productive conversation should be considered as one of the foundations of intervention efforts. We suggest that intervention facilitators consider the following actions as strategies for reducing the barriers that conversation can present and for using conversation to leverage improvement change: evaluate existing conversation and relationship systems, look for and leverage unexpected conversation, create time and space where conversation can unfold, use conversation to help people manage uncertainty, use conversation to help reorganize relationships, and build social interaction competence.</p

Prominent radiative contributions from multiply-excited states in laser-produced tin plasma for nanolithography

Extreme ultraviolet (EUV) lithography is currently entering high-volume manufacturing to enable the continued miniaturization of semiconductor devices. The required EUV light, at 13.5 nm wavelength, is produced in a hot and dense laser-driven tin plasma. The atomic origins of this light are demonstrably poorly understood. Here we calculate detailed tin opacity spectra using the Los Alamos atomic physics suite ATOMIC and validate these calculations with experimental comparisons. Our key finding is that EUV light largely originates from transitions between multiply-excited states, and not from the singly-excited states decaying to the ground state as is the current paradigm. Moreover, we find that transitions between these multiply-excited states also contribute in the same narrow window around 13.5 nm as those originating from singly-excited states, and this striking property holds over a wide range of charge states. We thus reveal the doubly magic behavior of tin and the origins of the EUV light