The adaptive value of camouflage and colour change in a polymorphic prawn

This is the author accepted manuscript. The final version is available from Springer Nature via the DOI in this record.Camouflage has been a textbook example of natural selection and adaptation since the time of the earliest evolutionists. However, aside from correlational evidence and studies using artificial dummy prey, experiments directly showing that better camouflaged prey to predator vision are at reduced risk of attack are lacking. Here, we show that the level of camouflage achieved through colour adjustments towards the appearance of seaweed habitats is adaptive in reducing predation pressure in the prawn Hippolyte obliquimanus. Digital image analysis and visual modelling of a fish predator (seahorse) predicted that brown prawns would be imperfectly concealed against both brown and red seaweed respectively, whereas pink prawns should be well camouflaged only in red weed. Predation trials with captive seahorses (Hippocampus reidi), coupled with high-speed video analyses, closely matched model predictions: predation rates were similar for brown prawns between seaweed types, but pink individuals were attacked significantly less on red than brown weed. Our work provides some of the clearest direct evidence to date that colour polymorphism and colour change provides a clear adaptive advantage for camouflage, and also highlights how this can be asymmetric across morphs and habitats (i.e. dependent on the specific background-morph combination).This study was funded by the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) which granted a PhD fellowship to RCD (#2012/17003-0, #2015/04484-8), and a visiting professor grant to MS (#2015/22258-5)

Different ontogenetic trajectories of body colour, pattern, and crypsis in two sympatric intertidal crab species

This is the author accepted manuscript. The final version is available from Oxford University Press via the DOI in this recordAnimals frequently exhibit high appearance variation, especially in heterogeneous habitats where individuals may be differentially concealed against backgrounds. While background matching is a common anti-predator strategy, gaps exist in understanding within- and among-species variation. Specifically, the drivers of appearance changes associated with habitat use and occurring through ontogeny are poorly understood. Using image analysis, we tested how individual appearance and camouflage in two intertidal crab species – the mud crab Panopeus americanus and the mottled crab Pachygrapsus transversus – relates to ontogeny and habitat use. We predicted that both species would change appearance with ontogeny, but resident mud crabs would exhibit higher background similarity than generalist mottled crabs. Both species showed ontogenetic changes, but while mud crabs become darker, mottled crabs turn greener. Small mud crabs were highly variable in colour and pattern, likely stemming from utilising camouflage in heterogeneous habitats during the most vulnerable life-stage. Being habitat specialists, mud crabs concealed better against all backgrounds than mottled crabs. Mottled crabs are motile and generalist, occupying macroalgal-covered rocks when adults, which explain why they are greener and why matches to specific habitats are less valuable. Differential habitat use in crabs can be associated with different coloration and camouflage strategies to avoid predation.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológic

High star formation rates as the origin of turbulence in early and modern disk galaxies

High spatial and spectral resolution observations of star formation and kinematics in early galaxies have shown that two-thirds are massive rotating disk galaxies with the remainder being less massive non-rotating objects. The line of sight averaged velocity dispersions are typically five times higher than in today's disk galaxies. This has suggested that gravitationally-unstable, gas-rich disks in the early Universe are fuelled by cold, dense accreting gas flowing along cosmic filaments and penetrating hot galactic gas halos. However these accreting flows have not been observed, and cosmic accretion cannot power the observed level of turbulence. Here we report on a new sample of rare high-velocity-dispersion disk galaxies we have discovered in the nearby Universe where cold accretion is unlikely to drive their high star-formation rates. We find that the velocity dispersion is most fundamentally correlated with their star-formation rates, and not their mass nor gas fraction, which leads to a new picture where star formation itself is the energetic driver of galaxy disk turbulence at all cosmic epochs.Comment: 9 pages, 2 figures, Supplimentary Info available at: http://pulsar.swin.edu.au/~agreen/nature/sigma_mean_arXiv.pdf. Accepted for publication in Natur

Risk Factors of Porcine Cysticercosis in the Eastern Cape Province, South Africa

There is a high prevalence of Taenia solium taeniosis/cysticercosis in humans and pigs in the Eastern Cape Province (ECP) of South Africa. The objective of this study was to identify risk factors of porcine cysticercosis in select districts of the ECP. Data were collected in 2003 by interviewing 217 pig producers from the area. Blood samples were collected from 261 of their pigs, which were tested using two enzyme-linked immunosorbent assays (ELISA) for the presence of antibodies to cysticercosis. Frequencies of both owner- and pig-level characteristics were determined. For pig-level analysis, all bivariable and multivariable associations were determined using the surveylogistic procedure of the SAS/STAT® software to accommodate for the intraclass correlation that exists for clusters of pigs within one owner and for clusters of owners within a district. All tests for significance were performed at the α = 0.05 level, and adjusted odds ratios (aOR) and 95% confidence intervals (CI) were determined. Among the respondents, 48% of their households lacked a latrine, 98% slaughtered pigs at home, and 99% indicated that meat inspection services were not available. On bivariable analysis, there was a significant association between porcine infection and district (p = 0.003), breed (p = 0.041) and the absence of a latrine (p = 0.006). On multivariable analysis, the absence of a latrine was the only variable significantly associated with porcine infection (aOR = 1.89; 95% CI = 1.07, 3.35) (p = 0.028). The increased odds of porcine infection with households lacking a latrine contributes to our understanding of the transmission of this parasite in the ECP. Determining and addressing the risk factors for T. solium infection can potentially lower the very high prevalence in humans and pigs in this endemic area

Management of Septated Malignant Pleural Effusions

Purpose of Review: We review recent studies of patients with septated malignant pleural effusions, to understand what the clinical implications for patients are and what evidence-based methods should be used to manage these effusions. Recent Findings: Fibrinolytics improve effusion size assessed radiologically in patients with a chest drain inserted for septated malignant pleural effusions but this does not translate into an improvement in breathlessness relief or pleurodesis success. Fibrinolytics have also been used in patients with septated effusions associated with indwelling pleural catheters, but dyspnoea relief has not been assessed in this population. Patients with septated effusions or extensive adhesions appear to have a worse prognosis. Summary: Patients with septated malignant pleural effusions have a poor prognosis and do not gain clinical benefit from fibrinolytics via chest drain. The role of fibrinolytics for septated effusions associated with indwelling pleural catheters requires further study

Transient Changes in Bacterioplankton Communities Induced by the Submarine Volcanic Eruption of El Hierro (Canary Islands)

Postprint4,411

ruvA Mutants that resolve Holliday junctions but do not reverse replication forks

RuvAB and RuvABC complexes catalyze branch migration and resolution of Holliday junctions (HJs) respectively. In addition to their action in the last steps of homologous recombination, they process HJs made by replication fork reversal, a reaction which occurs at inactivated replication forks by the annealing of blocked leading and lagging strand ends. RuvAB was recently proposed to bind replication forks and directly catalyze their conversion into HJs. We report here the isolation and characterization of two separation-of-function ruvA mutants that resolve HJs, based on their capacity to promote conjugational recombination and recombinational repair of UV and mitomycin C lesions, but have lost the capacity to reverse forks. In vivo and in vitro evidence indicate that the ruvA mutations affect DNA binding and the stimulation of RuvB helicase activity. This work shows that RuvA's actions at forks and at HJs can be genetically separated, and that RuvA mutants compromised for fork reversal remain fully capable of homologous recombination

Coxiella burnetii Phagocytosis Is Regulated by GTPases of the Rho Family and the RhoA Effectors mDia1 and ROCK

The GTPases belonging to the Rho family control the actin cytoskeleton rearrangements needed for particle internalization during phagocytosis. ROCK and mDia1 are downstream effectors of RhoA, a GTPase involved in that process. Coxiella burnetii, the etiologic agent of Q fever, is internalized by the host´s cells in an actin-dependent manner. Nevertheless, the molecular mechanism involved in this process has been poorly characterized. This work analyzes the role of different GTPases of the Rho family and some downstream effectors in the internalization of C. burnetii by phagocytic and non-phagocytic cells. The internalization of C. burnetii into HeLa and RAW cells was significantly inhibited when the cells were treated with Clostridium difficile Toxin B which irreversibly inactivates members of the Rho family. In addition, the internalization was reduced in HeLa cells that overexpressed the dominant negative mutants of RhoA, Rac1 or Cdc42 or that were knocked down for the Rho GTPases. The pharmacological inhibition or the knocking down of ROCK diminished bacterium internalization. Moreover, C. burnetii was less efficiently internalized in HeLa cells overexpressing mDia1-N1, a dominant negative mutant of mDia1, while the overexpression of the constitutively active mutant mDia1-ΔN3 increased bacteria uptake. Interestingly, when HeLa and RAW cells were infected, RhoA, Rac1 and mDia1 were recruited to membrane cell fractions. Our results suggest that the GTPases of the Rho family play an important role in C. burnetii phagocytosis in both HeLa and RAW cells. Additionally, we present evidence that ROCK and mDia1, which are downstream effectors of RhoA, are involved in that processFil: Salinas Ojeda, Romina Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Cienicas Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Ortiz Flores, Rodolfo Matias. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Cienicas Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Distel, Jesús Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Cienicas Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Aguilera, Milton Osmar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Cienicas Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Colombo, Maria Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Cienicas Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Beron, Walter. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Cienicas Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; Argentin

Decontamination of 16S rRNA gene amplicon sequence datasets based on bacterial load assessment by qPCR

Identification of unexpected taxa in 16S rRNA surveys of low-density microbiota, diluted mock communities and cultures demonstrated that a variable fraction of sequence reads originated from exogenous DNA. The sources of these contaminants are reagents used in DNA extraction, PCR, and next-generation sequencing library preparation, and human (skin, oral and respiratory) microbiota from the investigators