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Thursday, 14 January 2016

What's new for 'birdRS' in PubMed. January Week 2, 2016

birdRS - Latest News

This message contains My NCBI what's new results from the National Center for Biotechnology Information (NCBI) at the U.S. National Library of Medicine (NLM).

PubMed Results

1. Mol Endocrinol. 2016 Jan 8:me20151270. [Epub ahead of print]

Research Resource: Hormones, genes and athleticism: effect of androgens on the avian muscular transcriptome. 
Fuxjager MJ(1,)(2,)(3), Lee JH(4,)(5,)(2), Chan TM(2), Bahn JH(2), Chew JG(2), Xiao X(2), Schlinger BA(2,)(3,)(6). Author information: (1)Department of Biology, Wake Forest University, 228 Winston Hall, Winston-Salem, NC 27109, USA. (2)Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA 90095, USA. (3)Laboratory of Neuroendocrinology, Brain Research Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA. (4)Department of Life and Nanopharmaceutical Sciences, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul 130-701, Republic of Korea. (5)Department of Maxillofacial Biomedical Engineering, School of Dentistry, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul 130-701, Republic of Korea. (6)Smithsonian Tropical Research Institute, Apartado Postal 0843-03092, Balboa, Ancón, Panama. 

Male vertebrate social displays vary from physically simple to complex, with the latter involving exquisite motor command of the body and appendages. Studies of these displays have, in turn, provided substantial insight into neuro-motor mechanisms. The neotropical golden-collared manakin (Manacus vitellinus) has been used previously as a model to investigate intricate motor skills, as adult males of this species perform an acrobatic and androgen-dependent courtship display. To support this behavior, these birds express elevated levels of androgen-receptors (AR) in their skeletal muscles. Here, we use RNA sequencing (RNA-Seq) to explore how testosterone modulates the muscular transcriptome to support male manakin courtship displays. In addition, we explore how androgens influence gene expression in muscles of the zebra finch (Taenopygia guttata), a model passerine bird with a limited courtship display and minimal muscle AR. We identify androgen-dependent, muscle-specific gene regulation in both species. In addition, we identify manakin-specific effects that are linked to muscle use during the manakin display, including androgenic regulation of genes associated with muscle fiber contractility, cellular homeostasis and energetic efficiency. Overall, our results point to numerous genes and gene networks impacted by androgens in male birds including some that underlie optimal muscle function necessary for performing acrobatic display routines. Manakins are excellent models to explore gene regulation promoting athletic ability. PMID: 26745669 [PubMed - as supplied by publisher] 

2. Poult Sci. 2016 Jan 6. pii: pev268. [Epub ahead of print] 

Heterogeneous size datasets of broiler intestinal microbial communities can be analyzed without normalisation. 
Aranda-Olmedo I(1), Rubio LA(2). Author information: (1)Fisiología y Bioquímica de la Nutrición Animal (EEZ, CSIC), Profesor Albareda, 1 18008 Granada, Spain. (2)Fisiología y Bioquímica de la Nutrición Animal (EEZ, CSIC), Profesor Albareda, 1 18008 Granada, Spain  

Next-generation sequencing technologies have become a powerful tool for the analysis of microbial communities. Sequencing of the hypervariable regions of the 16S ribosomal RNA gene following the amplitag amplification process has allowed the study of the diversity of samples of diverse origin. According to previous reports, the number of sequences required for the correct determination of the composition of a given sample may vary with the degree of diversity of that sample. In this paper, we investigate the correctness of comparing heterogeneous size datasets of bird intestinal microbial communities obtained from pyrosequencing data (Roche 454 technology) without prior normalization. We conclude that the differences observed between samples are due mainly to individual differences, not to differences in the number of readings in each sample, which makes data normalization unnecessary with the conditions described here. © 2016 Poultry Science Association Inc. PMID: 26740134 [PubMed - as supplied by publisher] 

3. Mol Biol Evol. 2016 Jan 6. pii: msv343. [Epub ahead of print] 

Selection on mitochondrial variants occurs between and within individuals in an expanding invasion. 
Rollins LA(1), Woolnough AP(2), Fanson BG(3), Cummins ML(4), Crowley TM(5), Wilton AN(6), Sinclair R(7), Butler A(3), Sherwin WB(8). Author information: (1)Deakin University, Geelong, Australia. School of Life and Environmental Sciences, Centre for Integrative Ecology, Locked Bag 20000, Geelong, Victoria, 3220, Australia Evolution & Ecology Research Centre; Biological, Earth and Environmental Sciences; University of New South Wales, Sydney, New South Wales, 2052, Australia (2)Biosecurity Branch, Department of Economic Development, Jobs, Transport and Resources, 475 Mickleham Road, Attwood, VIC, 3049, Australia Vertebrate Pest Research Section, Department of Agriculture and Food Western Australia, 100 Bougainvillea Avenue, Forrestfield, WA 6058, Australia. (3)Deakin University, Geelong, Australia. School of Life and Environmental Sciences, Centre for Integrative Ecology, Locked Bag 20000, Geelong, Victoria, 3220, Australia. (4)School of Medicine, Deakin University, Locked Bag 20000, Geelong, Victoria, 3220, Australia. (5)School of Medicine, Deakin University, Locked Bag 20000, Geelong, Victoria, 3220, Australia Biosecurity Flagship, CSIRO Australian Animal Health Laboratory, PO Box 24, Geelong, Victoria, 3220, Australia. (6)School of Biotechnology and Biomolecular Science, University of New South Wales, Sydney, New South Wales, 2052, Australia. (7)Biosecurity SA, GPO Box 1671, Adelaide, South Australia, 5001, Australia. (8)Evolution & Ecology Research Centre; Biological, Earth and Environmental Sciences; University of New South Wales, Sydney, New South Wales, 2052, Australia Murdoch University Cetacean Research Unit, Murdoch University, South Road, Murdoch, WA 6150, Australia. 

Mitochondria are critical for life, yet their underlying evolutionary biology is poorly understood. In particular, little is known about interaction between two levels of evolution: between individuals and within individuals (competition between cells, mitochondria or mitochondrial DNA molecules). Rapid evolution is suspected to occur frequently in mitochondrial DNA, whose maternal inheritance predisposes advantageous mutations to sweep rapidly though populations. Rapid evolution is also predicted in response to changed selection regimes after species invasion or removal of pathogens or competitors. Here, using empirical and simulated data from a model invasive bird species, we provide the first demonstration of rapid selection on the mitochondrial genome within individuals in the wild. Further, we show differences in mitochondrial DNA copy number associated with competing genetic variants, which may provide a mechanism for selection. We provide evidence for three rarely documented phenomena: selection associated with mitochondrial DNA abundance; selection on the mitochondrial control region; and contemporary selection during invasion. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: PMID: 26739881 [PubMed - as supplied by publisher] 

4. Ticks Tick Borne Dis. 2015 Dec 17. pii: S1877-959X(15)30042-X. doi: 10.1016/j.ttbdis.2015.12.001. [Epub ahead of print] 

Studies abound on how north Ixodes scapularis ticks are transported by birds. 
Scott JD(1). Author information: (1)Research Division, Lyme Ontario, 365 St. David Street South, Fergus, ON, Canada N1M 2L7. Electronic address: 

Several studies report migratory songbirds transporting ticks northward during spring migration in Canada. The blacklegged tick, Ixodes scapularis, has been documented on Neotropical songbirds as far as Slave Lake, Alberta during northbound spring migration. In addition, Ixodes ticks have been collected from passerine migrants as far north as Watson Lake, Yukon (north of 60th latitude). The presence of Amblyomma ticks parasitizing long-distance migrants, which are moving from wintering grounds in the Neotropics to breeding grounds in Canada, confirms Neotropical songbirds transport ixodid ticks into Canada. Our avian, tick-host studies document 22 species of ticks on wild birds in Canada, and the majority of these species are not indigenous in Canada. Some of these songbird-transported ticks originate from as far south as Brazil. Clearly, passerine migrants transport ticks long distances into Canada during northward spring migration. The importation of ticks into Canada by migratory songbirds is no longer a "hypothesis," it is a fact. Copyright © 2015 Elsevier GmbH. All rights reserved. PMID: 26739029 [PubMed - as supplied by publisher] 

5. BMC Res Notes. 2016 Jan 7;9(1):14. doi: 10.1186/s13104-015-1797-1. 

Molecular forensics in avian conservation: a DNA-based approach for identifying mammalian predators of ground-nesting birds and eggs. 
Hopken MW(1), Orning EK(2,)(3), Young JK(4,)(5), Piaggio AJ(6). Author information: (1)United States Department of Agriculture, Wildlife Services, National Wildlife Research Center, Fort Collins, CO, USA. (2)Department of Wildland Resources, Utah State University, Logan, UT, USA. (3)Oregon Cooperative Fish and Wildlife Research Unit, Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR, USA. (4)Department of Wildland Resources, Utah State University, Logan, UT, USA. (5)United States Department of Agriculture, Wildlife Services, National Wildlife Research Center, Logan, UT, USA. (6)United States Department of Agriculture, Wildlife Services, National Wildlife Research Center, Fort Collins, CO, USA. 

BACKGROUND: The greater sage-grouse (Centrocercus urophasianus) is a ground-nesting bird from the Northern Rocky Mountains and a species at risk of extinction in in multiple U.S. states and Canada. Herein we report results from a proof of concept that mitochondrial and nuclear DNAs from mammalian predator saliva could be non-invasively collected from depredated greater sage-grouse eggshells and carcasses and used for predator species identification. Molecular forensic approaches have been applied to identify predators from depredated remains as one strategy to better understand predator-prey dynamics and guide management strategies. This can aid conservation efforts by correctly identifying predators most likely to impact threatened and endangered species. DNA isolated from non-invasive samples around nesting sites (e.g. fecal or hair samples) is one method that can increase the success and accuracy of predator species identification when compared to relying on nest remains alone. RESULTS: Predator saliva DNA was collected from depredated eggshells and carcasses using swabs. We sequenced two partial fragments of two mitochondrial genes and obtained microsatellite genotypes using canid specific primers for species and individual identification, respectively. Using this multilocus approach we were able to identify predators, at least down to family, from 11 out of 14 nests (79 %) and three out of seven carcasses (47 %). Predators detected most frequently were canids (86 %), while other taxa included rodents, a striped skunk, and cattle. We attempted to match the genotypes of individual coyotes obtained from eggshells and carcasses with those obtained from fecal samples and coyotes collected in the areas, but no genotype matches were found. CONCLUSION: Predation is a main cause of nest failure in ground-nesting birds and can impact reproduction and recruitment. To inform predator management for ground-nesting bird conservation, accurate identification of predator species is necessary. Considering predation can have a high impact on recruitment, predation events are very difficult to observe, and predator species are difficult to identify visually from nest remains, molecular approaches that reduce the need to observe or handle animals offer an additional tool to better understand predator-prey dynamics at nesting sites. PMID: 26738484 [PubMed - in process] 

6. J Food Prot. 2016 Jan;79(1):75-81. doi: 10.4315/0362-028X.JFP-15-331. 

Prevalence and Distribution of Campylobacter jejuni in Small-Scale Broiler Operations. 
Tangkham W(1), Janes M(2), LeMieux F(3). Author information: (1)Department of Agricultural Sciences, McNeese State University, Lake Charles, Louisiana 70609, USA. (2)School of Nutrition and Food Sciences, Louisiana State University Agricultural Center, Baton Rouge, Louisiana 70803, USA. (3)Department of Agricultural Sciences, McNeese State University, Lake Charles, Louisiana 70609, USA. 

Campylobacter jejuni has been recognized as one of the most prevalent causes of foodborne bacterial illnesses in humans. Previous studies have focused on the transmission routes of C. jejuni from commercial flock farms to the final retail product. The objective of this study was to determine the prevalence of C. jejuni and Campylobacter spp. in eggshells, live birds, feed, drinking water, and the rearing environment in a small-scale broiler operation. Broilers were raised under two different production systems: (i) environmentally controlled housing and (ii) open-air housing with two replications. Each week, samples were collected from eggshells, bird feces, feed, drinking water, enclosures (vertical walls of bird housing), and feed troughs for enumeration and isolation testing. All samples were plated on modified charcoal-cefoperazone-deoxycholate agar to determine the log CFU per gram and percent prevalence of Campylobacter spp. Isolation of C. jejuni was verified with latex agglutination and hippurate hydrolysis tests. The results from this study suggest that vertical transmission of these bacteria from egg surfaces to newly hatched chicks is not a significant risk factor. The results also suggest that the prevalence of C. jejuni at time of harvest (week 6) was significantly higher (P < 0.05) in the open-air housing broilers than in those in the environmentally controlled housing. Elevated levels of cross-contaminants, especially water and feed, may have played a role in this outcome. PMID: 26735032 [PubMed - in process] 

7. Front Microbiol. 2015 Dec 21;6:1403. doi: 10.3389/fmicb.2015.01403. eCollection 2015. 

Comparative Gut Microbiota of 59 Neotropical Bird Species. 
Hird SM(1), Sánchez C(1), Carstens BC(2), Brumfield RT(1). Author information: (1)Museum of Natural Science, Louisiana State UniversityBaton Rouge, LA, USA; Department of Biological Sciences, Louisiana State UniversityBaton Rouge, LA, USA. (2)Department of Evolution, Ecology and Organismal Biology, Ohio State University Columbus, OH, USA. 

The gut microbiota of vertebrates are essential to host health. Most non-model vertebrates, however, lack even a basic description of natural gut microbiota biodiversity. Here, we sampled 116 intestines from 59 Neotropical bird species and used the V6 region of the 16S rRNA molecule as a microbial fingerprint (average coverage per bird ~80,000 reads). A core microbiota of Proteobacteria, Firmicutes, Bacteroidetes, and Actinobacteria was identified, as well as several gut-associated genera. We tested 18 categorical variables associated with each bird for significant correlation to the gut microbiota; host taxonomic categories were most frequently significant and explained the most variation. Ecological variables (e.g., diet, foraging stratum) were also frequently significant but explained less variation. Little evidence was found for a significant influence of geographic space. Finally, we suggest that microbial sampling during field collection of organisms would propel biological understanding of evolutionary history and ecological significance of host-associated microbiota. PMCID: PMC4685052 PMID: 26733954 [PubMed] 

8. Naturwissenschaften. 2016 Feb;103(1-2):4. doi: 10.1007/s00114-015-1328-x. Epub 2016 Jan 5. 

Side-specific effect of yolk testosterone elevation on second-to-fourth digit ratio in a wild passerine. 
Nagy G(1), Blázi G(1), Hegyi G(1), Török J(2). Author information: (1)Behavioural Ecology Group, Department of Systematic Zoology and Ecology, Eötvös Loránd University, Pázmány P. sétány 1/C, H-1117, Budapest, Hungary. (2)Behavioural Ecology Group, Department of Systematic Zoology and Ecology, Eötvös Loránd University, Pázmány P. sétány 1/C, H-1117, Budapest, Hungary. 

Second-to-fourth digit ratio is a widely investigated sexually dimorphic morphological trait in human studies and could reliably indicate the prenatal steroid environment. Conducting manipulative experiments to test this hypothesis comes up against ethical limits in humans. However, oviparous tetrapods may be excellent models to experimentally investigate the effects of prenatal steroids on offspring second-to-fourth digit ratio. In this field study, we injected collared flycatcher (Ficedula albicollis) eggs with physiological doses of testosterone. Fledglings from eggs with elevated yolk testosterone, regardless of their sex, had longer second digits on their left feet than controls, while the fourth digit did not differ between groups. Therefore, second-to-fourth digit ratio was higher in the testosterone-injected group, but only on the left foot. This is the first study which shows experimentally that early testosterone exposure can affect second-to-fourth digit ratio in a wild population of a passerine bird. PMID: 26732381 [PubMed - in process] 

9. PLoS One. 2016 Jan 5;11(1):e0144600. doi: 10.1371/journal.pone.0144600. eCollection 2016. 

Bird-Window Collisions at a West-Coast Urban Park Museum: Analyses of Bird Biology and Window Attributes from Golden Gate Park, San Francisco. 
Kahle LQ(1), Flannery ME(1), Dumbacher JP(1). Author information: (1)Department of Ornithology and Mammalogy, Institute of Biodiversity Science and Sustainability, The California Academy of Sciences, Golden Gate Park, 55 Music Concourse Drive, San Francisco, CA, 94118, United States of America. 

Bird-window collisions are a major and poorly-understood generator of bird mortality. In North America, studies of this topic tend to be focused east of the Mississippi River, resulting in a paucity of data from the Western flyways. Additionally, few available data can critically evaluate factors such as time of day, sex and age bias, and effect of window pane size on collisions. We collected and analyzed 5 years of window strike data from a 3-story building in a large urban park in San Francisco, California. To evaluate our window collision data in context, we collected weekly data on local bird abundance in the adjacent parkland. Our study asks two overarching questions: first-what aspects of a bird's biology might make them more likely to fatally strike windows; and second, what characteristics of a building's design contribute to bird-window collisions. We used a dataset of 308 fatal bird strikes to examine the relationships of strikes relative to age, sex, time of day, time of year, and a variety of other factors, including mitigation efforts. We found that actively migrating birds may not be major contributors to collisions as has been found elsewhere. We found that males and young birds were both significantly overrepresented relative to their abundance in the habitat surrounding the building. We also analyzed the effect of external window shades as mitigation, finding that an overall reduction in large panes, whether covered or in some way broken up with mullions, effectively reduced window collisions. We conclude that effective mitigation or design will be required in all seasons, but that breeding seasons and migratory seasons are most critical, especially for low-rise buildings and other sites away from urban migrant traps. Finally, strikes occur throughout the day, but mitigation may be most effective in the morning and midday. PMID: 26731417 [PubMed - in process] 

10. Sci Rep. 2016 Jan 4;6:17489. doi: 10.1038/srep17489. 

Impact of multiple bird partners on the seed dispersal effectiveness of China's relic trees. 
Li N(1,)(2), Li XH(3), An SQ(2), Lu CH(1). Author information: (1)Laboratory of Plant-Animal Interactions, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China. (2)School of Life Science, Nanjing University, Nanjing 210046, Jiangsu, China. (3)Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China. 

Frugivorous birds generally exhibit an unequal contribution to dispersal effectiveness of plant species as a function of their habitat adaptation and body size. In our study, we compared the effectiveness of multiple bird species that contribute to the dispersal of the endangered relic Chinese yew, Taxus chinensis. Seven bird species dispersed T. chinensis seeds, with Picus canus, Turdus hortulorum, and Urocissa erythrorhyncha being the main dispersers. The quantity part of dispersal effectiveness was strongly influenced by two inherent characteristics of disperser species: body size and habitat adaptation. However, the quality part of dispersal effectiveness was only influenced by disperser type. For instance, small generalist birds and large specialist birds removed more seeds than other type dispersers. Moreover, small birds and specialist birds contributed slightly more to the dispersal quality of T. chinensis than large birds and generalist birds respectively; however, these differences were not significant. Our results suggest that dispersal effectiveness is affected by variety in the body size and habitat adaptation of different dispersers. Therefore, such variation should be incorporated into spatial and temporal management actions of relic plant species in patchy, human-disturbed habitats. PMID: 26725517 [PubMed - in process] 

11. Theriogenology. 2015 Nov 30. pii: S0093-691X(15)00648-2. doi: 10.1016/j.theriogenology.2015.11.023. [Epub ahead of print] 

Semen evaluation in four autochthonous wild raptor species using computer-aided sperm analyser. 
Dogliero A(1), Rota A(2), Lofiego R(2), Mauthe von Degerfeld M(2), Quaranta G(2). Author information: (1)Dipartimento Scienze Veterinarie, Università di Torino, Grugliasco, Italy. Electronic address: (2)Dipartimento Scienze Veterinarie, Università di Torino, Grugliasco, Italy. 

At least 10 percent of the approximately 300 species of the order Falconiformes are listed as being globally threatened. The present work describes the seminal characteristics of three diurnal and one nocturnal raptor species. Semen was collected from clinically healthy Accipiter nisus (n = 1), Falco subbuteo (n = 6), and Falco tinnunculus (n = 5) adult males that were housed at the 'Centro Animali Non Convenzionali' of the Department of Veterinary Sciences of the University of Turin. The semen was collected after a period of recovery and before their release as well as from seven Bubo bubo males bred in captivity as part of a raptor conservation project. All the potential semen donors were trained in semen collection during the breeding season via a ritualized procedure. Ejaculation was achieved using a massaging technique. Each sample was evaluated for volume, degree of contamination, and spermatozoa concentration. The semen motility and kinetic parameters were assessed on diluted semen (modified tyroides albumin lactate pyruvate, pH 7.5, temperature 37.5 °C) using a computer-aided sperm analyzer. Semen collection was successful in all the diurnal species and in five B bubo individuals. The sperm motility and sperm kinetic parameters were very variable both among and within species. In contrast with previous studies that involved raptors bred in captivity and imprinted on humans, we worked with wild birds and attempted to overcome the problem of poor semen quality, which is strongly influenced by stress, by adopting a ritualized procedure that has never been reported for semen collection purposes. Copyright © 2015 Elsevier Inc. All rights reserved. PMID: 26725000 [PubMed - as supplied by publisher] 

12. Environ Res. 2015 Dec 24;146:73-84. doi: 10.1016/j.envres.2015.12.004. [Epub ahead of print] 

Short-term fasts increase levels of halogenated flame retardants in tissues of a wild incubating bird. 
Marteinson SC(1), Drouillard KG(2), Verreault J(3). Author information: (1)Centre de recherche en toxicologie de l'environnement (TOXEN), Département des sciences biologiques, Université du Québec à Montréal, C.P. 8888, Succursale Centre-ville, Montreal, QC, Canada H3C 3P8. (2)Great Lakes Institute for Environmental Research (GLIER), University of Windsor, 401 Sunset Avenue, Windsor, ON, Canada N9B 3P4. (3)Centre de recherche en toxicologie de l'environnement (TOXEN), Département des sciences biologiques, Université du Québec à Montréal, C.P. 8888, Succursale Centre-ville, Montreal, QC, Canada H3C 3P8. Electronic address: 

Many species are adapted for fasting during parts of their life cycle. For species undergoing extreme fasts, lipid stores are mobilized and accumulated contaminants can be released to exert toxicological effects. However, it is unknown if short-term fasting events may have a similar effect. The objective of this study was to determine if short successive fasts are related to contaminant levels in liver and plasma of birds. In ring-billed gulls (Larus delawarensis), both members of the pair alternate between incubating the nest for several hours (during which they fast) and foraging, making them a useful model for examining this question. Birds were equipped with miniature data loggers recording time and GPS position for two days to determine the proportion and duration of time birds spent in these two activities. Liver and plasma samples were collected, and halogenated flame retardants (HFRs) (PBDEs and dechlorane plus) and organochlorines (OCs) (PCBs, DDTs, and chlordane-related compounds) were determined. Most birds (79%) exhibited plasma lipid content below 1%, indicating a likely fasted state, and plasma lipid percent declined with the number of hours spent at the nest site. The more time birds spent at their nest site, the higher were their plasma and liver concentrations of HFRs. However, body condition indices were unrelated to either the amount of time birds fasted at the nest site or contaminant levels, suggesting that lipid mobilization might not have been severe enough to affect overall body condition of birds and to explain the relationship between fasting and HFR concentrations. A similar relationship between fasting and OC levels was not observed, suggesting that different factors are affecting short-term temporal variations in concentrations of these two classes of contaminants. This study demonstrates that short fasts can be related to increased internal contaminant exposure in birds and that this may be a confounding factor in research and monitoring involving tissue concentrations of HFRs in wild birds. Copyright © 2015 Elsevier Inc. All rights reserved. PMID: 26724461 [PubMed - as supplied by publisher] 

13. J Therm Biol. 2016 Jan;55:7-13. doi: 10.1016/j.jtherbio.2015.10.009. Epub 2015 Nov 28. 

The cooling time of fertile chicken eggs at different stages of incubation. 
Mortola JP(1), Gaonac'h-Lovejoy V(1). Author information: (1)McGill University, Department of Physiology, McIntyre Medical Sciences Bldg, Room 1121, 3655 Sir William Osler promenade, Montreal, Quebec, Canada H3G 1Y6. 

We asked whether or not the thermal characteristics of fertile avian eggs changed throughout incubation. The cooling and warming times, expressed by the time constant τ of the egg temperature response to a rapid change in ambient temperature, were measured in fertile chicken eggs at early (E7), intermediate (E11) and late (E20) stages of embryonic development. Same measurements were conducted on eggs emptied of their content and refilled with water by various amounts. The results indicated that (1) the τ of a freshly laid egg was ~50min; (2) τ decreased linearly with the drop in egg water volume; (3) the dry eggshell had almost no thermal resistance but its wet inner membrane contributed about one-third to the stability of egg temperature; (4) the egg constituents (yolk, albumen and embryonic tissues) and the chorioallantoic circulation had no measurable effect on τ; (5) the presence of an air pocket equivalent in volume to the air cell of fertile eggs reduced τ by about 3min (E7), 5min (E11) and 11min (E20). Hence, in response to warming the egg τ at E20 was slightly shorter than at E7. In response to cooling, the egg τ at E20 was similar to, or longer than, E7 because embryonic thermogenesis (evaluated by measurements of oxygen consumption during cold) offset the reduction in τ introduced by the air cell. In conclusion, until the onset of thermogenesis the thermal behavior of a fertile egg is closely approximated by that of a water-filled egg with an air volume equivalent to the air cell. It is possible to estimate the cooling τ of avian eggs of different species from their weight and incubation time. Copyright © 2015 Elsevier Ltd. All rights reserved. PMID: 26724192 [PubMed - in process] 

14. Ecology. 2015 Oct;96(10):2715-25. 

Invasive carnivores alter ecological function and enhance complementarity in scavenger assemblages on ocean beaches. 
Brown MB, Schlacher TA, Schoeman DS, Weston MA, Huijbers CM, Olds AD, Connolly RM. 

Species composition is expected to alter ecological function in assemblages if species traits differ strongly. Such effects are often large and persistent for nonnative carnivores invading islands. Alternatively, high similarity in traits within assemblages creates a degree of functional redundancy in ecosystems. Here we tested whether species turnover results in functional ecological equivalence or complementarity, and whether invasive carnivores on islands significantly alter such ecological function. The model system consisted of vertebrate scavengers (dominated by raptors) foraging on animal carcasses on ocean beaches on two Australian islands, one with and one without invasive red foxes (Vulpes vulpes). Partitioning of scavenging events among species, carcass removal rates, and detection speeds were quantified using camera traps baited with fish carcasses at the dune-beach interface. Complete segregation of temporal foraging niches between mammals (nocturnal) and birds (diurnal) reflects complementarity in carrion utilization. Conversely, functional redundancy exists within the bird guild where several species of raptors dominate carrion removal in a broadly similar way. As predicted, effects of red foxes were large. They substantially changed the nature and rate of the scavenging process in the system: (1) foxes consumed over half (55%) of all carrion available at night, compared with negligible mammalian foraging at night on the fox-free island, and (2) significant shifts in the composition of the scavenger assemblages consuming beach-cast carrion are the consequence of fox invasion at one island. Arguably, in the absence of other mammalian apex predators, the addition of red foxes creates a new dimension of functional complementarity in beach food webs. However, this functional complementarity added by foxes is neither benign nor neutral, as marine carrion subsidies to coastal red fox populations are likely to facilitate their persistence as exotic carnivores. PMID: 26649392 [PubMed - indexed for MEDLINE] 

15. Science. 2015 Nov 20;350(6263):928-32. doi: 10.1126/science.aad0843. 

Stable recombination hotspots in birds. 
Singhal S(1), Leffler EM(2), Sannareddy K(3), Turner I(4), Venn O(4), Hooper DM(5), Strand AI(6), Li Q(7), Raney B(8), Balakrishnan CN(9), Griffith SC(10), McVean G(4), Przeworski M(1). Author information: (1)Department of Biological Sciences, Columbia University, New York, NY 10027, USA. Department of Systems Biology, Columbia University, New York, NY 10032, USA. (2)Department of Human Genetics, University of Chicago, Chicago, IL 60637, USA. Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK. (3)Department of Human Genetics, University of Chicago, Chicago, IL 60637, USA. (4)Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK. (5)Committee on Evolutionary Biology, University of Chicago, Chicago, IL 60637, USA. (6)Department of Biological Sciences, Columbia University, New York, NY 10027, USA. (7)China National Genebank, BGI-Shenzhen, Shenzhen 518083, China. (8)Center for Biomolecular Science and Engineering, University of California-Santa Cruz, Santa Cruz, CA 95064, USA. (9)Department of Biology, East Carolina University, Greenville, NC 27858, USA. (10)Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia. Comment in Science. 2015 Nov 20;350(6263):913. 

The DNA-binding protein PRDM9 has a critical role in specifying meiotic recombination hotspots in mice and apes, but it appears to be absent from other vertebrate species, including birds. To study the evolution and determinants of recombination in species lacking the gene that encodes PRDM9, we inferred fine-scale genetic maps from population resequencing data for two bird species: the zebra finch, Taeniopygia guttata, and the long-tailed finch, Poephila acuticauda. We found that both species have recombination hotspots, which are enriched near functional genomic elements. Unlike in mice and apes, most hotspots are shared between the two species, and their conservation seems to extend over tens of millions of years. These observations suggest that in the absence of PRDM9, recombination targets functional features that both enable access to the genome and constrain its evolution. Copyright © 2015, American Association for the Advancement of Science. PMID: 26586757 [PubMed - indexed for MEDLINE]

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