Acetylation of Rec8 cohesin complexes regulates reductional chromosome segregation in meiosis

For establishing sister chromatid cohesion and proper chromosome segregation in mitosis in fission yeast, the acetyltransferase Eso1 plays a key role. Eso1 acetylates cohesin complexes, at two conserved lysine residues K105 and K106 of the cohesin subunit Psm3. Although Eso1 also contributes to reductional chromosome segregation in meiosis, the underlying molecular mechanisms have remained elusive. Here, we purified meiosis-specific Rec8 cohesin complexes localized at centromeres and identified a new acetylation at Psm3-K1013, which largely depends on the meiotic kinetochore factor meikin (Moa1). Our molecular genetic analyses indicate that Psm3-K1013 acetylation cooperates with canonical acetylation at Psm3-K105 and K106, and plays a crucial role in establishing reductional chromosome segregation in meiosis.

RNA polymerase II dynamics and mRNA stability feedback scale mRNA amounts with cell size

A fundamental feature of cellular growth is that total protein and RNA amounts increase with cell size to keep concentrations approximately constant. A key component of this is that global transcription rates increase in larger cells. Here, we identify RNA polymerase II (RNAPII) as the limiting factor scaling mRNA transcription with cell size in budding yeast, as transcription is highly sensitive to the dosage of RNAPII but not to other components of the transcriptional machinery. Our experiments support a dynamic equilibrium model where global RNAPII transcription at a given size is set by the mass action recruitment kinetics of unengaged nucleoplasmic RNAPII to the genome. However, this only drives a sub-linear increase in transcription with size, which is then partially compensated for by a decrease in mRNA decay rates as cells enlarge. Thus, limiting RNAPII and feedback on mRNA stability work in concert to scale mRNA amounts with cell size.

Intestinal microbiota of Nearctic-Neotropical migratory birds vary more over seasons and years than between host species

Seasonal migration of Nearctic-Neotropical passerine birds may have profound effects on the diversity and abundance of their host-associated microbiota. Migratory birds experience seasonal change in environments and diets throughout the course of the annual cycle that, along with recurrent biological events such as reproduction, may significantly impact their microbiota. In this study, we characterize the intestinal microbiota of four closely related species of migratory Catharus thrushes at three time points of their migratory cycle: during spring migration, on the summer breeding territories and during fall migration. Using observations replicated over 3 years, we determined that microbial community diversity of Catharus thrushes was significantly different across distinct time periods of the annual cycle, whereas community composition was more similar within than across years. Elevated alpha diversity in the summer birds compared to either migratory period indicated that birds may harbour a reduced microbiota during active migration. We also found that community composition of the microbiota did not substantially differ between host species. Finally, we recovered two phyla, Cyanobacteria and Planctomycetota, which are not commonly described from birds, that were in relatively high abundance in specific years. This study contributes to our growing understanding of how microbiota in wild birds vary throughout disparate ecological conditions and reveals potential axes across which an animal's microbial flexibility adapts to variable environments and recurrent biological conditions throughout the annual cycle.

Genetic evidence for widespread population size expansion in North American boreal birds prior to the Last Glacial Maximum

Pleistocene climate cycles are well documented to have shaped contemporary species distributions and genetic diversity. Northward range expansions in response to deglaciation following the Last Glacial Maximum (LGM; approximately 21 000 years ago) are surmised to have led to population size expansions in terrestrial taxa and changes in seasonal migratory behaviour. Recent findings, however, suggest that some northern temperate populations may have been more stable than expected through the LGM. We modelled the demographic history of 19 co-distributed boreal-breeding North American bird species from full mitochondrial gene sets and species-specific molecular rates. We used these demographic reconstructions to test how species with different migratory strategies were affected by glacial cycles. Our results suggest that effective population sizes increased in response to Pleistocene deglaciation earlier than the LGM, whereas genetic diversity was maintained throughout the LGM despite shifts in geographical range. We conclude that glacial cycles prior to the LGM have most strongly shaped contemporary genetic diversity in these species. We did not find a relationship between historic population dynamics and migratory strategy, contributing to growing evidence that major switches in migratory strategy during the LGM are unnecessary to explain contemporary migratory patterns.

Search for Subsolar-Mass Binaries in the First Half of Advanced LIGO's and Advanced Virgo's Third Observing Run

We report on a search for compact binary coalescences where at least one binary component has a mass between 0.2  M_{⊙} and 1.0  M_{⊙} in Advanced LIGO and Advanced Virgo data collected between 1 April 2019 1500 UTC and 1 October 2019 1500 UTC. We extend our previous analyses in two main ways: we include data from the Virgo detector and we allow for more unequal mass systems, with mass ratio q≥0.1. We do not report any gravitational-wave candidates. The most significant trigger has a false alarm rate of 0.14  yr^{-1}. This implies an upper limit on the merger rate of subsolar binaries in the range [220-24200]  Gpc^{-3} yr^{-1}, depending on the chirp mass of the binary. We use this upper limit to derive astrophysical constraints on two phenomenological models that could produce subsolar-mass compact objects. One is an isotropic distribution of equal-mass primordial black holes. Using this model, we find that the fraction of dark matter in primordial black holes in the mass range 0.2  M_{⊙}<m_{PBH}<1.0  M_{⊙} is f_{PBH}≡Ω_{PBH}/Ω_{DM}≲6%. This improves existing constraints on primordial black hole abundance by a factor of ∼3. The other is a dissipative dark matter model, in which fermionic dark matter can collapse and form black holes. The upper limit on the fraction of dark matter black holes depends on the minimum mass of the black holes that can be formed: the most constraining result is obtained at M_{min}=1  M_{⊙}, where f_{DBH}≡Ω_{DBH}/Ω_{DM}≲0.003%. These are the first constraints placed on dissipative dark models by subsolar-mass analyses.

How Nordic Countries Enforce Impaired Driving Legislation

This article reviews how the Nordic countries of Denmark, Finland, Norway, and Sweden enforce their legislation pertaining to driving under the influence of alcohol and/or other impairing drugs. The evidence necessary for a successful prosecution of traffic offenders has undergone radical changes over the past 50 years. The once widely used clinical tests of impairment are no longer a major element of the prosecution case and a physician is more seldom required to examine apprehended drivers and document any clinical signs and symptoms of alcohol and/or drug influence. These clinical tests have been superseded by results derived from a comprehensive toxicological analysis of psychoactive substances in samples of the driver's blood. The current statutory limits of blood-alcohol concentration (BAC) are among the lowest in the world: Norway and Sweden (0.20 g/kg) and Denmark and Finland (0.50 g/kg). Results from using evidential quality breath-alcohol instruments are accepted as evidence in drunk-driving cases and this has necessitated setting statutory breath-alcohol concentration (BrAC) limits. Laws dealing with driving under the influence of drugs (DUID) other than alcohol have also been updated and made more pragmatic for prosecution of traffic offenders. In Finland and Sweden zero-tolerance laws exist, making it illegal to drive with any quantifiable amount of a scheduled drug in the driver's blood. Prescription drugs are exempt from this zero-tolerance mandate provided the medication was used in accordance with a physician's ordination. Lacking a valid prescription or if there is a supratherapeutic concentration of the drug in blood, this will lead to a prosecution for DUID. In Denmark and Norway threshold concentration limits have been established for many psychoactive drugs, both licit and illicit. After these stricter laws for DUID were introduced, the number of suspects apprehended by the police per year increased by as much as tenfold in some Nordic countries. There is increasing evidence that many traffic delinquents in the Nordic countries suffer from a substance-use disorder, because repeat-offending is a common occurrence. This suggests that some type of treatment and rehabilitation program might be more beneficial compared with conventional penalties for people arrested for DUI and/or DUID.

Core control principles of the eukaryotic cell cycle

Cyclin-dependent kinases (CDKs) lie at the heart of eukaryotic cell cycle control, with different cyclin-CDK complexes initiating DNA replication (S-CDKs) and mitosis (M-CDKs)^1,2. However, the principles on which cyclin-CDK complexes organize the temporal order of cell cycle events are contentious³. One model proposes that S-CDKs and M-CDKs are functionally specialized, with substantially different substrate specificities to execute different cell cycle events^4-6. A second model proposes that S-CDKs and M-CDKs are redundant with each other, with both acting as sources of overall CDK activity^7,8. In this model, increasing CDK activity, rather than CDK substrate specificity, orders cell cycle events^9,10. Here we reconcile these two views of core cell cycle control. Using phosphoproteomic assays of in vivo CDK activity in fission yeast, we find that S-CDK and M-CDK substrate specificities are remarkably similar, showing that S-CDKs and M-CDKs are not completely specialized for S phase and mitosis alone. Normally, S-CDK cannot drive mitosis but can do so when protein phosphatase 1 is removed from the centrosome. Thus, increasing S-CDK activity in vivo is sufficient to overcome substrate specificity differences between S-CDK and M-CDK, and allows S-CDK to carry out M-CDK function. Therefore, we unite the two opposing views of cell cycle control, showing that the core cell cycle engine is largely based on a quantitative increase in CDK activity through the cell cycle, combined with minor and surmountable qualitative differences in catalytic specialization of S-CDKs and M-CDKs.

The TOR-dependent phosphoproteome and regulation of cellular protein synthesis

Cell growth is orchestrated by a number of interlinking cellular processes. Components of the TOR pathway have been proposed as potential regulators of cell growth, but little is known about their immediate effects on protein synthesis in response to TOR‐dependent growth inhibition. Here, we present a resource providing an in‐depth characterisation of Schizosaccharomyces pombe phosphoproteome in relation to changes observed in global cellular protein synthesis upon TOR inhibition. We find that after TOR inhibition, the rate of protein synthesis is rapidly reduced and that notable phosphorylation changes are observed in proteins involved in a range of cellular processes. We show that this reduction in protein synthesis rates upon TOR inhibition is not dependent on S6K activity, but is partially dependent on the S. pombe homologue of eIF4G, Tif471. Our study demonstrates the impact of TOR‐dependent phospho‐regulation on the rate of protein synthesis and establishes a foundational resource for further investigation of additional TOR‐regulated targets both in fission yeast and other eukaryotes.

Clinical and forensic toxicology of methanol

Methanol has a very simple chemical structure (CH3OH) considering its potential health hazard, including the many poisoning deaths after ingestion. In countries where authentic alcoholic beverages are expensive, restricted, or banned for religious or other reasons, some people resort to purchasing alcoholic drinks made illegally. These clandestine sources of "booze" often contain high concentrations of methanol, added by the perpetrators to enhance potency and increase profits. Although an effective medical treatment for methanol poisoning exists, because most such incidents occur in socially deprived parts of the world, the hospital emergency facilities are scarce and/or inadequate. Trace amounts of methanol (median ~1.0 mg/L) are produced endogenously via certain enzymatic processes, such as one-carbon metabolism. Methanol and methyl esters are also contained in fresh fruits and vegetables as well as in alcoholic beverages. During a period of heavy drinking the blood-methanol concentration (BMC) increases and might surpass 10 mg/L, which is considered a biomarker for alcohol abuse and alcoholism. Methanol itself has a low intrinsic toxicity, but is converted in the body into two highly toxic metabolites, formaldehyde and formic acid. This metabolism is delayed by co-ingestion of ethanol, which creates a latent period of 12-24 h before toxic symptoms develop. Accordingly, when patients are admitted to hospital for diagnosis and treatment, a life-threatening metabolic acidosis has already developed and is irreversible. Symptoms of methanol poisoning include blurred vision, breathlessness, nausea, gastric pains, and acid-base disturbances and deficiency of oxygen in arterial blood. The visual disturbances might even develop into permanent blindness, owing to an interaction of toxic metabolites with the optic nerve. The minimum lethal dose of ethanol in humans is not easy to specify, because most poisonings involve co-ingestion of ethanol, which to some extent protects the patient from toxic sequelae. Effective antidotes for treatment of methanol poisoning are administration of ethanol or the therapeutic drug fomepizole (Antizol®), which is 4-methyl pyrazole (4-MP). Both treatments work by blocking the metabolism of methanol by liver alcohol dehydrogenase (ADH). The metabolic acidosis caused by the accumulation of formic acid in the body is treated with sodium bicarbonate, which helps to normalize pH in the bloodstream. Thereafter, methanol and its metabolites in the blood are removed by hemodialysis. However, the long-term prognosis for survivors of methanol poisoning is not good, because many are elderly males who are in poor health and often suffer from an alcohol-use disorder.

Constraints on Cosmic Strings Using Data from the Third Advanced LIGO-Virgo Observing Run

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.

Constraints on Cosmic Strings Using Data from the Third Advanced LIGO-Virgo Observing Run

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.

A century of intermittent eco-evolutionary feedbacks resulted in novel trait combinations in invasive Great Lakes alewives (Alosa pseudoharengus)

Species introductions provide opportunities to quantify rates and patterns of evolutionary change in response to novel environments. Alewives (Alosa pseudoharengus) are native to the East Coast of North America where they ascend coastal rivers to spawn in lakes and then return to the ocean. Some populations have become landlocked within the last 350 years and diverged phenotypically from their ancestral marine population. More recently, alewives were introduced to the Laurentian Great Lakes (~150 years ago), but these populations have not been compared to East Coast anadromous and landlocked populations. We quantified 95 years of evolution in foraging traits and overall body shape of Great Lakes alewives and compared patterns of phenotypic evolution of Great Lakes alewives to East Coast anadromous and landlocked populations. Our results suggest that gill raker spacing in Great Lakes alewives has evolved in a dynamic pattern that is consistent with responses to strong but intermittent eco-evolutionary feedbacks with zooplankton size. Following their initial colonization of Lakes Ontario and Michigan, dense alewife populations likely depleted large-bodied zooplankton, which drove a decrease in alewife gill raker spacing. However, the introduction of large, non-native zooplankton to the Great Lakes in later decades resulted in an increase in gill raker spacing, and present-day Great Lakes alewives have gill raker spacing patterns that are similar to the ancestral East Coast anadromous population. Conversely, contemporary Great Lakes alewife populations possess a gape width consistent with East Coast landlocked populations. Body shape showed remarkable parallel evolution with East Coast landlocked populations, likely due to a shared response to the loss of long-distance movement or migrations. Our results suggest the colonization of a new environment and cessation of migration can result in rapid parallel evolution in some traits, but contingency also plays a role, and a dynamic ecosystem can also yield novel trait combinations.

Increased sensitivity of higher-order laser beams to mode mismatches

This Letter derives explicit factors linking mode-mismatch-induced power losses in Hermite-Gauss optical modes to the losses of the fundamental spatial mode. Higher-order modes are found to be more sensitive to beam parameter mismatches. This is particularly relevant for gravitational-wave detectors, where lasers employing higher-order optical modes have been proposed to mitigate thermal noise, and quantum-enhanced detectors are very susceptible to losses. This work should inform mode matching and squeezing requirements for Advanced+ and third generation detectors.

Cdc14 and PP2A Phosphatases Cooperate to Shape Phosphoproteome Dynamics during Mitotic Exit

Temporal control over protein phosphorylation and dephosphorylation is crucial for accurate chromosome segregation and for completion of the cell division cycle during exit from mitosis. In budding yeast, the Cdc14 phosphatase is thought to be a major regulator at this time, while in higher eukaryotes PP2A phosphatases take a dominant role. Here, we use time-resolved phosphoproteome analysis in budding yeast to evaluate the respective contributions of Cdc14, PP2A^Cdc55, and PP2A^Rts1. This reveals an overlapping requirement for all three phosphatases during mitotic progression. Our time-resolved phosphoproteome resource reveals how Cdc14 instructs the sequential pattern of phosphorylation changes, in part through preferential recognition of serine-based cyclin-dependent kinase (Cdk) substrates. PP2A^Cdc55 and PP2A^Rts1 in turn exhibit a broad substrate spectrum with some selectivity for phosphothreonines and a role for PP2A^Rts1 in sustaining Aurora kinase activity. These results illustrate synergy and coordination between phosphatases as they orchestrate phosphoproteome dynamics during mitotic progression.

•

Cdc14, PP2A^Cdc55, and PP2A^Rts1 phosphatases cooperate during budding yeast mitosis

•

Cdc14 targets serine Cdk motifs for rapid dephosphorylation

•

PP2A^Cdc55 dephosphorylates Cdk and Plk substrates on threonine residues

•

PP2A^Rts1 displays regulatory crosstalk with Aurora kinase

GW190521: A Binary Black Hole Merger with a Total Mass of 150 M_{⊙}

On May 21, 2019 at 03:02:29 UTC Advanced LIGO and Advanced Virgo observed a short duration gravitational-wave signal, GW190521, with a three-detector network signal-to-noise ratio of 14.7, and an estimated false-alarm rate of 1 in 4900 yr using a search sensitive to generic transients. If GW190521 is from a quasicircular binary inspiral, then the detected signal is consistent with the merger of two black holes with masses of 85_{-14}^{+21}  M_{⊙} and 66_{-18}^{+17}  M_{⊙} (90% credible intervals). We infer that the primary black hole mass lies within the gap produced by (pulsational) pair-instability supernova processes, with only a 0.32% probability of being below 65  M_{⊙}. We calculate the mass of the remnant to be 142_{-16}^{+28}  M_{⊙}, which can be considered an intermediate mass black hole (IMBH). The luminosity distance of the source is 5.3_{-2.6}^{+2.4}  Gpc, corresponding to a redshift of 0.82_{-0.34}^{+0.28}. The inferred rate of mergers similar to GW190521 is 0.13_{-0.11}^{+0.30}  Gpc^{-3} yr^{-1}.

Genomic identification of intergeneric hybrids in New World wood-warblers (Aves: Parulidae)

The documentation of hybrids between distantly related taxa can illustrate an initial step to explain how genes might move between species that do not exhibit complete reproductive isolation. In birds, some of the most phylogenetically distant hybrid combinations occur between genera. Traditionally, morphological and plumage characters have been used to assign the identity of the parental species of a putative hybrid, although recently, nuclear introns also have been used. Here, we demonstrate how high-throughput short-read DNA sequence data can be used to identify the parentage of a putative intergeneric hybrid, in this case between a blue-winged warbler (Vermivora cyanoptera) and a cerulean warbler (Setophaga cerulea). This hybrid had mitochondrial DNA of a cerulean warbler, indicating the maternal parent. For hundreds of single nucleotide polymorphisms within six regions of the nuclear genome that differentiate blue-winged warblers and golden-winged warblers (Vermivora chrysoptera), the hybrid had roughly equal ancestry assignment to blue-winged and cerulean warblers, suggesting a blue-winged warbler as the paternal parent species and demonstrating that this was a first generation (F1) hybrid between these species. Unlike other recently characterized intergeneric warbler hybrids, this individual hybrid learned to song match its maternal parent species, suggesting that it might have been the result of an extra-pair mating and raised in a cerulean warbler nest.

Assessing Budding Yeast Phosphoproteome Dynamics in a Time-Resolved Manner using TMT10plex Mass Tag Labeling

Amine-reactive Tandem Mass Tag 10plex (TMT10plex) labeling permits multiplexed protein identification and quantitative analysis by tandem mass spectrometry (MS/MS). We have used this technology to label 20 Saccharomyces cerevisiae samples collected in a time-resolved manner from a wild-type and phosphatase mutant background to characterize phosphoproteome dynamics. Here, we provide a detailed protocol for biological and mass spectrometry sample preparation and analysis. For complete details on the use and execution of this protocol, please refer to Touati et al. (2019).

•

Characterization of the phosphoproteome in a time-resolved manner

•

TMT10plex Mass Tag labelling of budding yeast extracts

•

Mass spectrometry sample preparation and analysis

Drivers of community turnover differ between avian hemoparasite genera along a North American latitudinal gradient

The latitudinal diversity gradient (LDG) is an established macroecological pattern, but is poorly studied in microbial organisms, particularly parasites. In this study, we tested whether latitude, elevation, and host species predicted patterns of prevalence, alpha diversity, and community turnover of hemosporidian parasites. We expected parasite diversity to decrease with latitude, alongside the diversity of their hosts and vectors. Similarly, we expected infection prevalence to decrease with latitude as vector abundances decrease. Lastly, we expected parasite community turnover to increase with latitudinal distance and to be higher between rather than within host species. We tested these hypotheses by screening blood and tissue samples of three closely related avian species in a clade of North American songbirds (Turdidae: Catharus, n = 466) across 17.5° of latitude. We used a nested PCR approach to identify parasites in hemosporidian genera that are transmitted by different dipteran vectors. Then, we implemented linear-mixed effects and generalized dissimilarity models to evaluate the effects of latitude, elevation, and host species on parasite metrics. We found high diversity of hemosporidian parasites in Catharus thrushes (n = 44 lineages) but no evidence of latitudinal gradients in alpha diversity or prevalence. Parasites in the genus Leucocytozoon were most prevalent and lineage rich in this study system; however, there was limited turnover with latitude and host species. Contrastingly, Plasmodium parasites were less prevalent and diverse than Leucocytozoon parasites, yet communities turned over at a higher rate with latitude and host species. Leucocytozoon communities were skewed by the dominance of one or two highly prevalent lineages with broad latitudinal distributions. The few studies that evaluate the hemosporidian LDG do not find consistent patterns of prevalence and diversity, which makes it challenging to predict how they will respond to global climate change.

High dynamic range spatial mode decomposition

An accurate readout of low-power optical higher-order spatial modes is of increasing importance to the precision metrology community. Mode sensors are used to prevent mode mismatches from degrading quantum and thermal noise mitigation strategies. Direct mode analysis sensors (MODAN) are a promising technology for real-time monitoring of arbitrary higher-order modes. We demonstrate MODAN with photo-diode readout to mitigate the typically low dynamic range of CCDs. We look for asymmetries in the response of our sensor to break degeneracies in the relative alignment of the MODAN and photo-diode and consequently improve the dynamic range of the mode sensor. We provide a tolerance analysis and show methodology that can be applied for sensors beyond first order spatial modes.

High Correlation between Ethanol Concentrations in Postmortem Femoral Blood and in Alternative Biological Specimens, but Large Uncertainty When the Linear Regression Model Was Used for Prediction in Individual Cases

In connection with medicolegal autopsies peripheral blood (e.g. from a femoral vein) is the specimen of choice for toxicological analysis, although alternative specimens are also sometimes submitted, such as bile, cerebrospinal fluid (CSF), vitreous humor (VH), bladder urine, pleural effusions and/or lung fluid. Ethanol concentrations were determined in duplicate in femoral blood and in various alternative biological specimens by headspace gas chromatography. The analysis was carried out on two different fused silica capillary columns furnishing different retention times for ethanol and both n-propanol and t-butanol were used as internal standards. The results were evaluated by linear regression using blood alcohol concentration (BAC) as dependent or outcome variable and the concentrations in an alternative specimen as independent or predictor variable. The Pearson correlation coefficients were all statistically highly significant (P &lt; 0.001); r = 0.94 (bile), r = 0.98 (CSF), r = 0.97 (VH), r = 0.92 (urine), r = 0.94 (lung fluid) and r = 0.96 (pleural cavity effusions). When the regression model was used to predict femoral BAC from the mean concentration in an alternative specimen the mean and 95% prediction intervals were 1.12 ± 0.824 g/L (bile), 1.41 ± 0.546 g/L (CSF), 1.15 ± 0.42 g/L (VH), 1.29 ± 0.780 g/L (urine), 1.25 ± 0.772 g/L (lung fluid) and 0.68 ± 0.564 g/L (pleural cavity effusions). This large uncertainty for a single new observation needs to be considered when alcohol-related deaths are evaluated and interpreted. However, the analysis of alternative specimens is recommended in medical examiner cases to provide supporting evidence with regard to the origin of ethanol, whether this reflects antemortem (AM) ingestion or postmortem (PM) synthesis.

The Hydrophobic Patch Directs Cyclin B to Centrosomes to Promote Global CDK Phosphorylation at Mitosis

The cyclin-dependent kinases (CDKs) are the major cell-cycle regulators that phosphorylate hundreds of substrates, controlling the onset of S phase and M phase [1, 2, 3]. However, the patterns of substrate phosphorylation increase are not uniform, as different substrates become phosphorylated at different times as cells proceed through the cell cycle [4, 5]. In fission yeast, the correct ordering of CDK substrate phosphorylation can be established by the activity of a single mitotic cyclin-CDK complex [6, 7]. Here, we investigate the substrate-docking region, the hydrophobic patch, on the fission yeast mitotic cyclin Cdc13 as a potential mechanism to correctly order CDK substrate phosphorylation. We show that the hydrophobic patch targets Cdc13 to the yeast centrosome equivalent, the spindle pole body (SPB), and disruption of this motif prevents both centrosomal localization of Cdc13 and the onset of mitosis but does not prevent S phase. CDK phosphorylation in mitosis is compromised for approximately half of all mitotic CDK substrates, with substrates affected generally being those that require the highest levels of CDK activity to become phosphorylated and those that are located at the SPB. Our experiments suggest that the hydrophobic patch of mitotic cyclins contributes to CDK substrate selection by directing the localization of Cdc13-CDK to centrosomes and that this localization of CDK contributes to the CDK substrate phosphorylation necessary to ensure proper entry into mitosis. Finally, we show that mutation of the hydrophobic patch prevents cyclin B1 localization to centrosomes in human cells, suggesting that this mechanism of cyclin-CDK spatial regulation may be conserved across eukaryotes.

•

The hydrophobic patch of human and yeast cyclin B directs it to the centrosome

•

Loss of the yeast cyclin B hydrophobic patch allows S phase but prevents mitosis

•

Compartmentalized mitotic CDK phosphorylation relies on the hydrophobic patch

Variation in individual autumn migration and winter paths of Great Lakes red-headed woodpeckers (Melanerpes erythrocephalus)

Migratory movements of facultative migrants are poorly understood due to their irregular and often unpredictable occurrence. However, tracking such movements is important for understanding population dynamics, informing annual cycle conservation plans, and identifying possible cues of facultative migration. We used pinpoint GPS tags to track autumn and winter movements of migratory red-headed woodpeckers (Melanerpes erythrocephalus) to better understand migration frequency, timing, and routes for birds breeding in managed oak savanna systems in the North American Great Lakes region. Proportions of individuals migrating differed between the two sites, with 72% of the Ohio population migrating, while no individuals in the Minnesota population migrated. Of the Ohio birds that migrated, their movements were highly variable in distance and direction but generally occurred south of the breeding site. Wintering sites ranged from 111 – 218 km from the breeding site. Cover types occupied during migration and wintering were almost exclusively small patches of closed-canopy hardwood forest within agricultural matrices. We documented one-time movements in migratory and non-migratory individuals during the year that have not previously been described in facultative migrants. We found no evidence of a harness or marker effect on proportions of individuals migrating, migration return rates, or annual survival regardless of migration.

Pharmacokinetics of ethanol in saliva: comparison with blood and breath alcohol profiles, subjective feelings of intoxication, and diminished performance

The concentration-time profiles of ethanol were determined for capillary blood, end-expired breath, and saliva after 21 healthy men ingested ethanol at 0.68 g/kg body weight. Near the time of obtaining body fluids, the volunteers estimated their feelings of intoxication, and body sway (with open and closed eyes), hand tremor, positional alcohol nystagmus (PAN), and roving ocular movements (ROM) were quantitatively recorded. The concentration-time profiles of ethanol in blood, breath, and saliva agreed well within individuals but there were large variations between subjects. The mean saliva-ethanol profiles ran slightly above those for blood and breath. Subjective ratings of intoxication and impairment of body function (standing steadiness and hand steadiness) were highest at the time of reaching the peak concentrations of ethanol in body fluids. PAN was evident in most subjects between 60 and 120 min after the start of drinking, whereas ROM appeared mainly during the postabsorptive phase of ethanol kinetics (120-420 min). The blood ethanol concentration thresholds were between 500 and 700 mg/L (50-70 mg/dL) when the diminished performance had recovered to baseline values.

Quantitative Phosphoproteomics Reveals the Signaling Dynamics of Cell-Cycle Kinases in the Fission Yeast Schizosaccharomyces pombe

Multiple protein kinases regulate cell-cycle progression, of which the cyclin-dependent kinases (CDKs) are thought to act as upstream master regulators. We have used quantitative phosphoproteomics to analyze the fission yeast cell cycle at sufficiently high temporal resolution to distinguish fine-grain differences in substrate phosphorylation dynamics on a proteome-wide scale. This dataset provides a useful resource for investigating the regulatory dynamics of cell-cycle kinases and their substrates. For example, our analysis indicates that the substrates of different mitotic kinases (CDK, NIMA-related, Polo-like, and Aurora) are phosphorylated in sequential, kinase-specific waves during mitosis. Phosphoproteomics analysis after chemical-genetic manipulation of CDK activity suggests that the timing of these waves is established by the differential dependency of the downstream kinases on upstream CDK. We have also examined the temporal organization of phosphorylation during G1/S, as well as the coordination between the NDR-related kinase Orb6, which controls polarized growth, and other cell-cycle kinases.

•

Global analysis of phosphorylation dynamics during the fission yeast cell cycle

•

Reveals kinase-specific waves of phosphorylation throughout interphase and mitosis

•

Mitotic kinases show significantly different dependencies on upstream CDK activity

•

Kinases directly downstream of CDK mediate earlier waves of mitotic phosphorylation

Search for Subsolar Mass Ultracompact Binaries in Advanced LIGO's Second Observing Run

We present a search for subsolar mass ultracompact objects in data obtained during Advanced LIGO's second observing run. In contrast to a previous search of Advanced LIGO data from the first observing run, this search includes the effects of component spin on the gravitational waveform. We identify no viable gravitational-wave candidates consistent with subsolar mass ultracompact binaries with at least one component between 0.2  M_{⊙}-1.0  M_{⊙}. We use the null result to constrain the binary merger rate of (0.2  M_{⊙}, 0.2  M_{⊙}) binaries to be less than 3.7×10^{5}  Gpc^{-3} yr^{-1} and the binary merger rate of (1.0  M_{⊙}, 1.0  M_{⊙}) binaries to be less than 5.2×10^{3}  Gpc^{-3} yr^{-1}. Subsolar mass ultracompact objects are not expected to form via known stellar evolution channels, though it has been suggested that primordial density fluctuations or particle dark matter with cooling mechanisms and/or nuclear interactions could form black holes with subsolar masses. Assuming a particular primordial black hole (PBH) formation model, we constrain a population of merging 0.2  M_{⊙} black holes to account for less than 16% of the dark matter density and a population of merging 1.0  M_{⊙} black holes to account for less than 2% of the dark matter density. We discuss how constraints on the merger rate and dark matter fraction may be extended to arbitrary black hole population models that predict subsolar mass binaries.

Driving under the influence of psychoactive substances - A historical review

Important events in the history of driving under the influence of alcohol (DUI) and/or other drugs (DUID) are reviewed covering a period of approximately 100 years. This coincides with major developments in the pharmaceutical industry and the exponential growth in motor transportation worldwide. DUID constitutes an interaction between the driver, the motor-driven vehicle, and one or more psychoactive (mind-altering) substances. In this connection, it is important to differentiate between drugs intended and used for medical purposes (prescription or licit drugs) and recreational drugs of abuse (illicit drugs). All chemicals with a mechanism of action in the central nervous system (brain and spinal cord) are potentially dangerous to use when skilled tasks, such as driving, are performed. The evidence necessary to charge a person with drug-impaired driving has evolved over many years and initially rested on a driver's own admissions and observations made about the driving by police officers or eyewitnesses. Somewhat later, all suspects were examined by a physician, whose task was to ask questions about any recent ingestion of alcohol and/or other drugs and to administer various clinical tests of impairment. By the 1940s-1950s, the driver was asked to provide samples of blood, breath, or urine for toxicological analysis, although the test results served only to verify the type of drug causing impairment of the driver. The current trend in DUID legislation is toward zero-tolerance or concentration per se statutes, which are much more pragmatic, because behavioral evidence of impairment is no longer a lynchpin in the prosecution case. This legal framework puts considerable emphasis on the results of toxicological analysis; therefore, the methods used must be accurate, precise, and fit for forensic purposes. Many traffic delinquents charged with DUI or DUID suffer from a substance use and/or personality disorder, with high recidivism rates. In addition to conventional penalties and sanctions for drug-related traffic crimes, many offenders would probably benefit from a medical intervention, such as counseling, rehabilitation, and treatment for substance use disorder, which often coexists with a mental health problem.

Nocturnal flight-calling behaviour predicts vulnerability to artificial light in migratory birds

Understanding interactions between biota and the built environment is increasingly important as human modification of the landscape expands in extent and intensity. For migratory birds, collisions with lighted structures are a major cause of mortality, but the mechanisms behind these collisions are poorly understood. Using 40 years of collision records of passerine birds, we investigated the importance of species' behavioural ecologies in predicting rates of building collisions during nocturnal migration through Chicago, IL and Cleveland, OH, USA. We found that the use of nocturnal flight calls is an important predictor of collision risk in nocturnally migrating passerine birds. Species that produce flight calls during nocturnal migration tended to collide with buildings more than expected given their local abundance, whereas those that do not use such communication collided much less frequently. Our results suggest that a stronger attraction response to artificial light at night in species that produce flight calls may mediate these differences in collision rates. Nocturnal flight calls probably evolved to facilitate collective decision-making during navigation, but this same social behaviour may now exacerbate vulnerability to a widespread anthropogenic disturbance. Our results also suggest that social behaviour during migration may reflect poorly understood differences in navigational mechanisms across lineages of birds.

Reduced Swimming Performance Repeatedly Evolves on Loss of Migration in Landlocked Populations of Alewife

Whole-organism performance tasks are accomplished by the integration of morphological traits and physiological functions. Understanding how evolutionary change in morphology and physiology influences whole-organism performance will yield insight into the factors that shape its own evolution. We demonstrate that nonmigratory populations of alewife (Alosa pseudoharengus) have evolved reduced swimming performance in parallel, compared with their migratory ancestor. In contrast to theoretically and empirically based predictions, poor swimming among nonmigratory populations is unrelated to the evolution of osmoregulation and occurs despite the fact that nonmigratory alewives have a more fusiform (torpedo-like) body shape than their ancestor. Our results suggest that elimination of long-distance migration from the life cycle has shaped performance more than changes in body shape and physiological regulatory capacity.

Phosphoproteome dynamics during mitotic exit in budding yeast

The cell division cycle culminates in mitosis when two daughter cells are born. As cyclin-dependent kinase (Cdk) activity reaches its peak, the anaphase-promoting complex/cyclosome (APC/C) is activated to trigger sister chromatid separation and mitotic spindle elongation, followed by spindle disassembly and cytokinesis. Degradation of mitotic cyclins and activation of Cdk-counteracting phosphatases are thought to cause protein dephosphorylation to control these sequential events. Here, we use budding yeast to analyze phosphorylation dynamics of 3,456 phosphosites on 1,101 proteins with high temporal resolution as cells progress synchronously through mitosis. This reveals that successive inactivation of S and M phase Cdks and of the mitotic kinase Polo contributes to order these dephosphorylation events. Unexpectedly, we detect as many new phosphorylation events as there are dephosphorylation events. These correlate with late mitotic kinase activation and identify numerous candidate targets of these kinases. These findings revise our view of mitotic exit and portray it as a dynamic process in which a range of mitotic kinases contribute to order both protein dephosphorylation and phosphorylation.

Heteromeric interactions regulate butyrophilin (BTN) and BTN-like molecules governing γδ T cell biology

The long-held view that gamma delta (γδ) T cells in mice and humans are fundamentally dissimilar, as are γδ cells in blood and peripheral tissues, has been challenged by emerging evidence of the cells' regulation by butyrophilin (BTN) and butyrophilin-like (BTNL) molecules. Thus, murine Btnl1 and the related gene, Skint1, mediate T cell receptor (TCR)-dependent selection of murine intraepithelial γδ T cell repertoires in gut and skin, respectively; BTNL3 and BTNL8 are TCR-dependent regulators of human gut γδ cells; and BTN3A1 is essential for TCR-dependent activation of human peripheral blood Vγ9Vδ2+ T cells. However, some observations concerning BTN/Btnl molecules continue to question the extent of mechanistic conservation. In particular, murine and human gut γδ cell regulation depends on pairings of Btnl1 and Btnl6 and BTNL3 and BTNL8, respectively, whereas blood γδ cells are reported to be regulated by BTN3A1 independent of other BTNs. Addressing this paradox, we show that BTN3A2 regulates the subcellular localization of BTN3A1, including functionally important associations with the endoplasmic reticulum (ER), and is specifically required for optimal BTN3A1-mediated activation of Vγ9Vδ2+ T cells. Evidence that BTNL3/BTNL8 and Btnl1/Btnl6 likewise associate with the ER reinforces the prospect of broadly conserved mechanisms underpinning the selection and activation of γδ cells in mice and humans, and in blood and extralymphoid sites.

A systematic genomic screen implicates nucleocytoplasmic transport and membrane growth in nuclear size control

How cells control the overall size and growth of membrane-bound organelles is an important unanswered question of cell biology. Fission yeast cells maintain a nuclear size proportional to cellular size, resulting in a constant ratio between nuclear and cellular volumes (N/C ratio). We have conducted a genome-wide visual screen of a fission yeast gene deletion collection for viable mutants altered in their N/C ratio, and have found that defects in both nucleocytoplasmic mRNA transport and lipid synthesis alter the N/C ratio. Perturbing nuclear mRNA export results in accumulation of both mRNA and protein within the nucleus, and leads to an increase in the N/C ratio which is dependent on new membrane synthesis. Disruption of lipid synthesis dysregulates nuclear membrane growth and results in an enlarged N/C ratio. We propose that both properly regulated nucleocytoplasmic transport and nuclear membrane growth are central to the control of nuclear growth and size.

CDK Substrate Phosphorylation and Ordering the Cell Cycle

S phase and mitotic onset are brought about by the action of multiple different cyclin-CDK complexes. However, it has been suggested that changes in the total level of CDK kinase activity, rather than substrate specificity, drive the temporal ordering of S phase and mitosis. Here, we present a phosphoproteomics-based systems analysis of CDK substrates in fission yeast and demonstrate that the phosphorylation of different CDK substrates can be temporally ordered during the cell cycle by a single cyclin-CDK. This is achieved by rising CDK activity and the differential sensitivity of substrates to CDK activity over a wide dynamic range. This is combined with rapid phosphorylation turnover to generate clearly resolved substrate-specific activity thresholds, which in turn ensures the appropriate ordering of downstream cell-cycle events. Comparative analysis with wild-type cells expressing multiple cyclin-CDK complexes reveals how cyclin-substrate specificity works alongside activity thresholds to fine-tune the patterns of substrate phosphorylation.

Structural Basis of Eco1-Mediated Cohesin Acetylation

Sister-chromatid cohesion is established by Eco1-mediated acetylation on two conserved tandem lysines in the cohesin Smc3 subunit. However, the molecular basis of Eco1 substrate recognition and acetylation in cohesion is not fully understood. Here, we discover and rationalize the substrate specificity of Eco1 using mass spectrometry coupled with in-vitro acetylation assays and crystallography. Our structures of the X. laevis Eco2 (xEco2) bound to its primary and secondary Smc3 substrates demonstrate the plasticity of the substrate-binding site, which confers substrate specificity by concerted conformational changes of the central β hairpin and the C-terminal extension.

Structure of the cohesin loader Scc2

The functions of cohesin are central to genome integrity, chromosome organization and transcription regulation through its prevention of premature sister-chromatid separation and the formation of DNA loops. The loading of cohesin onto chromatin depends on the Scc2-Scc4 complex; however, little is known about how it stimulates the cohesion-loading activity. Here we determine the large 'hook' structure of Scc2 responsible for catalysing cohesin loading. We identify key Scc2 surfaces that are crucial for cohesin loading in vivo. With the aid of previously determined structures and homology modelling, we derive a pseudo-atomic structure of the full-length Scc2-Scc4 complex. Finally, using recombinantly purified Scc2-Scc4 and cohesin, we performed crosslinking mass spectrometry and interaction assays that suggest Scc2-Scc4 uses its modular structure to make multiple contacts with cohesin.

Relation between bloodand urine-amphetamine concentrations in impaired drivers as influenced by urinary pH and creatinine

Amphetamine undergoes extensive renal excretion and significant amounts are present in urine as the unchanged parent drug. This prompted us to investigate whether a quantitative relationship existed between blood and urine concentrations of amphetamine in the body fluids of drug-impaired drivers apprehended in Sweden, where this stimulant is the major drug of abuse. The relationship between blood and urine concentrations of amphetamine was determined by multivariate analysis with urinary pH and creatinine as predictor variables. Amphetamine was determined in blood and urine by gas chromatography-mass spectrometry with deuterium labelled internal standards. The concentration of amphetamine in urine was about 200 times greater than the concentration in blood; the mean and median urine/blood ratios were 214 and 160, respectively, with large individual variations. The Pearson correlation coefficient between urine (y) and blood (x) amphetamine was r=0.53, n=48, which was statistically highly significant (P<0.001), although the residual standard deviation (SD) was large (±181 mg/L). The correlation coefficient increased (r=0.60) when the concentration of amphetamine in urine was normalized for dilution by dividing with the creatinine content. When urinary pH and creatinine were both included as predictor variables, the correlation coefficient was even higher (r=0.69), now explaining 48% (r2=0.48) of the variation in urine amphetamine concentration. However, the partial regression coefficient for creatinine (53±28.7) was not statistically significant (t=1.85, P>0.05), whereas the corresponding regression coefficient for pH was highly significant and had a negative sign (-1029±32.6, t=- 3.12, P < 0.005). Other factors could impact on the urine-blood amphetamine relationship, such as route of administration, pattern of voiding and time elapsed after use of the drug.

Longitudinal quantification of the gingival crevicular fluid proteome during progression from gingivitis to periodontitis in a canine model

Aim

Inflammatory periodontal disease is widespread in dogs. This study evaluated site‐specific changes in the canine gingival crevicular fluid (GCF) proteome during longitudinal progression from very mild gingivitis to mild periodontitis. Periodontitis diagnosis in dogs requires general anaesthesia with associated risks and costs; our ultimate aim was to develop a periodontitis diagnostic for application in conscious dogs. The objective of this work was to identify potential biomarkers of periodontal disease progression in dogs.

Material and Methods

Gingival crevicular fluid was sampled from a total of 10 teeth in eight dogs at three different stages of health/disease and samples prepared for quantitative mass spectrometry (data available via ProteomeXchange; identifier PXD003337). A univariate mixed model analysis determined significantly altered proteins between health states and six were evaluated by ELISA.

Results

Four hundred and six proteins were identified with 84 present in all samples. The prevalence of 40 proteins was found to be significantly changed in periodontitis relative to gingivitis. ELISA measurements confirmed that haptoglobin was significantly increased.

Conclusions

This study demonstrates for the first time that proteins detected by mass spectrometry have potential to identify novel biomarkers for canine periodontal disease. Further work is required to validate additional biomarkers for a periodontitis diagnostic.

Cause and manner of death and phase of the blood alcohol curve

In a large number of forensic autopsies (N = 28,184) the concentrations of ethanol in femoral blood and bladder urine were determined and the urine-to-blood concentration ratios of ethanol were calculated. Based on the differences in ethanol concentration between urine and blood, the deaths were classified as having occurred during the absorptive, the peak or the post-absorptive phase of the blood–alcohol curve. Most people died in the post-absorptive phase, N = 24,223 (86%), whereas 1538 individuals (5.5%) were still absorbing alcohol and 2423 (8.6%) were at or close to the peak BAC at time of death. Both blood–alcohol concentration (BAC) and urine–alcohol concentration (UAC) were significantly higher in the post-absorptive phase (p < 0.001). The proportions of people dying in the absorptive and peak phases increased with advancing age. The cause of death (CoD) and manner of death (MoD) according to death certificates were compared with phase of the blood–alcohol curve using a multinomial regression model with and without making adjustment for possible effects of age, gender and BAC. The relative risk (RR) and relative risk ratios (RRR) showed some associations between CoD and phase of the blood–alcohol curve. Undetermined MoD was significantly higher in the absorptive phase compared with the post-absorptive phase (RRR = 2.12). Deaths related to esophagus, stomach and duodenum (RRR = 2.04) and alcoholic liver diseases (RRR = 1.85) were significantly higher at or close to peak phase compared to the post-absorptive phase. Road-traffic fatalities were more prevalent in the peak BAC phase (RRR = 1.33) and deaths by accidental falls were less in the absorptive phase (RRR = 0.58) compared with the post-absorptive phase. The phase of alcohol intoxication seems relevant to consider by forensic experts when alcohol-related deaths are investigated.

Does intraspecific competition promote variation? A test via synthesis

Competitive diversification, that is, when increasing intraspecific competition promotes population niche expansion, is commonly invoked in evolutionary studies and currently plays a central role in how we conceptualize the process of adaptive diversification. Despite the frequency with which this idea is cited, the empirical evidence for the process is somewhat limited, and the findings of these studies have yet to be weighed objectively through synthesis. Here, we sought to fill this gap by reviewing the existing literature and collecting the data necessary to assess the evidence for competition as a diversifying force. Additionally, we sought to test a more recent hypothesis, which suggests that competition can act to both promote and inhibit dietary diversification depending on the degree to which a consumer depletes its resources. The surprising result of this synthesis was that increasing competition did not have a mean positive effect on population‐level diet breadth or the degree of individual specialization. Instead, we found that increasing intraspecific competition had a restricting effect on population‐level diet breadth in as many cases as it had a diversifying effect. This wide disparity in the effect of competition on consumer diet variation was negatively related to a metric for consumer resource depletion. Altogether, these findings call into question a long‐standing assumption of basic evolutionary models and lend some support to recent theoretical predictions. Specifically, these findings support the idea that competition is primarily diversifying for species with a small effect (per unit biomass) on their resources and that resource depletion limits the diversifying effect of competition for consumers with larger ecological effects.

Decreases in blood ethanol concentrations during storage at 4 °C for 12 months were the same for specimens kept in glass or plastic tubes

Background

The stability of ethanol was investigated in blood specimens in glass or plastic evacuated tubes after storage in a refrigerator at 4 °C for up to 12 months.

Methods

Sterile blood, from a local hospital, was divided into 50 mL portions and spiked with aqueous ethanol (10% w/v) to give target concentrations of 0.20, 1.00, 2.00 and 3.00 g/L. Ethanol was determined in blood by headspace gas chromatography (HS-GC) with an analytical imprecision of <3% (coefficient of variation, CV%). Aliquots of blood were re-analysed after 2, 7, 14, 28, 91, 182 and 364 days of storage at 4 °C.

Results

The standard deviation (SD) of analysis by HS-GC was 0.0059 g/L at 0.20 g/L and 0.0342 g/L at 3.00 g/L, corresponding to CVs of 2.9% and 1.1%, respectively. The decreases in blood ethanol content were analytically significant after 14–28 days of storage for both glass and plastic tubes The mean (lowest and highest) loss of ethanol after 12 months storage was 0.111 g/L (0.084–0.129 g/L) for glass tubes and 0.112 g/L (0.088–0.140 g/L) for plastic tubes. The corresponding percentage losses of ethanol were 43–45% at a starting concentration of 0.20 g/L and 3.9–4.1% at 3.00 g/L.

Conclusion

The concentration of ethanol in blood gradually decreases during storage at 4 °C. After 12 months storage the absolute decrease in concentration was ~0.11 g/L when the starting concentration ranged from 0.20 to 3.0 g/L. Decreases in ethanol content were the same for specimens kept in glass or plastic evacuated tubes.

Probing the electron capture dissociation mass spectrometry of phosphopeptides with traveling wave ion mobility spectrometry and molecular dynamics simulations

Electron capture dissociation mass spectrometry offers several advantages for the analysis of peptides, most notably that backbone c and z fragments typically retain labile modifications such as phosphorylation. We have shown previously that, in some cases, the presence of phosphorylation has a deleterious effect on peptide sequence coverage, and hypothesized that intramolecular interactions involving the phosphate group were preventing separation of backbone fragments. In the present work, we seek to rationalize the observed ECD behavior through a combination of ECD of model peptides, traveling wave ion mobility mass spectrometry and molecular dynamics simulations. The results suggest that for doubly protonated ions of phosphopeptide APLpSFRGSLPKSYVK a salt-bridge structure is favored, whereas for the doubly-protonated ions of APLSFRGSLPKpSYVK ionic hydrogen bonds predominate.

Precision, accuracy and relevance of breath alcohol measurements

The methods employed for evaluating the performance of some currently available breath alcohol devices are described. A program consisting of in vitro experiments, extensive in vivo laboratory studies, controlled field studies, and finally roadside random testing has been used. The importance of considering the underlying physiological mechanisms particularly with regard to the blood/breath partition ratio and its variability is emphasized. An important finding is that the relationship varies with the phase of alcohol metabolism in a regular and systematic way. Some statistical techniques are outlined for calculating the precision and accuracy of breath-testing instruments, which are important properties of a method to be used for medico-legal purposes.

Influence of 4 weeks of bovine colostrum supplementation on neutrophil and mucosal immune responses to prolonged cycling

Bovine colostrum (COL) has been advocated as a nutritional countermeasure to exercise-induced immune dysfunction. The aims of this study were to identify the effects of 4 weeks of COL supplementation on neutrophil responses and mucosal immunity following prolonged exercise. In a randomized double-blind, parallel group design, participants [age 28 ± 8 years; body mass 79 ± 7 kg; height 182 ± 6 cm; maximal oxygen uptake (V̇O2max) 55 ± 9 mL/kg/min] were assigned to 20 g per day of COL (n = 10) or an isoenergetic/isomacronutrient placebo (PLA; n = 10) for 4 weeks. Venous blood and unstimulated saliva samples were obtained before and after 2.5 h of cycling at 15% Δ (∼55-60% V̇O2max). A significantly greater formyl-methionyl-leucyl phenylalanine-stimulated oxidative burst was observed in the COL group compared with PLA group (P < 0.05) and a trend toward a time × group interaction (P = 0.06). However, there was no effect of COL on leukocyte trafficking, phorbol-12-myristate-13-acetate-stimulated oxidative burst, bacterial-stimulated neutrophil degranulation, salivary secretory IgA, lactoferrin or lysozyme (P > 0.05). These findings provide further evidence of the beneficial effects of COL on receptor-mediated stimulation of neutrophil oxidative burst in a model of exercise-induced immune dysfunction.

De novo design of Ln(III) coiled coils for imaging applications

A new peptide sequence (MB1) has been designed which, in the presence of a trivalent lanthanide ion, has been programmed to self-assemble to form a three stranded metallo-coiled coil, Ln(III)(MB1)₃. The binding site has been incorporated into the hydrophobic core using natural amino acids, restricting water access to the lanthanide. The resulting terbium coiled coil displays luminescent properties consistent with a lack of first coordination sphere water molecules. Despite this the gadolinium coiled coil, the first to be reported, displays promising magnetic resonance contrast capabilities.