Does low daily energy expenditure drive low metabolic capacity in the tropical robin, Turdus grayi?

Temperate and tropical birds possess divergent life history strategies. Physiological parameters including energy metabolism correlate with the life history such that tropical species with a slower ‘pace of life’ have lower resting and maximal metabolic rates than temperate congeners. To better understand the physiological mechanisms underlying these differences, we investigated the relationship of metabolic capacity, muscle oxidative capacity and activity patterns to variation in life history patterns in American robins (Turdus migratorius), while resident in central North America and Clay-colored robins (Turdus grayi) resident in Panama. We measured summit metabolism $ \left( {\dot{V}{\text{O}_{2\text{summit}}}} \right) $ in birds from both tropical and temperate habitats and found that the temperate robins have a 60 % higher metabolic capacity. We also measured the field metabolic rate (FMR) of free-living birds using heart rate (HR) telemetry and found that temperate robins’ daily energy expenditure was also 60 % higher. Thus, $\dot{V}{\text{O}_{2\text{summit}}} $ and FMR both reflect life history differences between the species. Further, both species operate at a nearly identical ~50 % of their thermogenic capacity throughout a given day. As a potential mechanism to explain differences in activity and metabolic capacity, we ask whether oxidative properties of flight muscle are altered in accordance with life history variation and found minimal differences in oxidative capacity of skeletal muscle. These data demonstrate a close relationship between thermogenic capacity and daily activity in free-living birds. Further, they suggest that the slow pace of life in tropical birds may be related to the maintenance of low activity rather than functional capacity of the muscle tissue.     

Claudin expression in breast cancer: High or low, what to expect?

The evaluation of claudins (CLDNs) expression pattern in tumours can be important to understand breast carcinogenesis. The study of CLDNs became more appealing since it was found that CLDN3 and CLDN4 are putative therapeutic targets for Clostridium perfrigens enterotoxin (CPE), as well as for monoclonal antibody-based therapy. Moreover, the recently characterized CLDN-low molecular subgroup of breast tumours increased the interest in these molecules. Based on these facts, our aim was to explore the pattern of expression of CLDNs among a large series of invasive breast carcinomas. We also analysed the correlation between the combinatorial expression of CLDN3/CLDN4 and classical prognostic factors and biological markers. In addition, we also compared the characteristics of tumours with low expression of CLDN3, CLDN4 and CLDN7, assessed by immunohistochemistry (IHC), and the ones from CLDN-low subgroup of tumours previously defined by genomic assays. The combinatorial analysis of the expression of CLDN3/CLDN4 showed a significant association between high CLDN3/CLDN4 levels and triple-negative tumours, as well as with worse patient outcome. This combined analysis may provide useful information for breast carcinomas, since these two CLDN members are putative therapeutic targets. Comparing tumours with low expression of CLDN3, CLDN4 and CLDN7 with tumours previously referred to as CLDN-low by genomic assays, we demonstrated that the single IHC evaluation of these three specific CLDNs is insufficient to identify the CLDN-low molecular subtype of breast tumours. The analysis of several other molecular markers, such as EMT (epithelial-to-mesenchymal transition) and CSC (cancer stem cell) markers should probably be added to improve the identification of this subgroup of tumours by IHC, which probably are enriched in carcinomas with metaplastic differentiation.     

The conservative low‐phosphorus niche in Proteaceae

Plant and Soil - Intercropping cereals with legumes may achieve high crop yields at reduced input levels. Several studies have indicated that intercropping increases phosphorus use efficiency but...     

Low blood pressure,low mood?

OBJECTIVE--To determine whether a set of physical symptoms is associated with low blood pressure and to investigate the possible role of psychological factors in their occurrence. DESIGN--Analysis of data collected by questionnaire and physical screening from the first phase of the Whitehall II study, a cohort study of an employed population. SETTING--23 civil service departments in London. SUBJECTS--10,314 male and female London based civil servants aged between 35 and 55. MAIN OUTCOME MEASURES--Symptoms of dizziness-giddiness and unexplained tiredness; psychological functioning as measured by the 30 item general health questionnaire in which the response "no more than usual" to an item about disease was scored as indicating chronic illness. RESULTS--Dizziness-giddiness in men and unexplained tiredness in both men and women were significantly related to low systolic blood pressure. There was a highly significant inverse relation between general health questionnaire score and systolic blood pressure for both men and women, which persisted after controlling for potentially confounding variables, including age, body mass index, drug treatment, physical illness, and exercise. This association of low blood pressure with physical symptoms was no longer significant when general health questionnaire score was controlled for. CONCLUSIONS--There seems a strong relation between low systolic blood pressure and minor psychological dysfunction. Associated physical symptoms seem to be secondary to the primary disturbance in mental state.     

Why is liana abundance low in semiarid climates?

Lianas are abundant in seasonal tropical forests, where they avoid seasonal water stress presumably by accessing deep‐soil water reserves. Although lianas are favoured in seasonal environments, their occurrence and abundance are low in semiarid environments. We hypothesized that lianas do not tolerate the great water shortage in the soil and air characteristic of semiarid environments, which would increase the risk of embolism. We compared the rooting depth of coarse roots, leaf dynamics, leaf water potential (ψ_leaf), embolism resistance (P₅₀) and lethal levels of embolism (P₈₈) between congeneric lianas that occur with different abundances in two semiarid sites differing in soil characteristics and vapour pressure deficit in the air (VPD_air). Regardless of soil texture and depth, water availability was restricted to the rainy season. All liana species were drought deciduous and had superficial coarse roots (not deeper than 35 cm). P₅₀ varied from ?1.8 to ?2.49 MPa, and all species operated under narrow safety margins against catastrophic (P₅₀) and irreversible hydraulic failure (P₈₈), even during the rainy season. In short, lianas that occur in semiarid environments have lower resistance to cavitation and limit carbon fixation to the rainy season because of leaf fall in the early dry season. We suggest that leaf shedding and shallow roots impairing carbon gain and growth in the dry season may explain why liana abundance is lower in semiarid than in other seasonally dry environments.     

Assessing genetic diversity in clonal organisms: low diversity or low resolution? Combining power and cost efficiency in selecting markers

The increasing use of molecular tools to study populations of clonal organisms leads us to question whether the low polymorphism found in many studies reflects limited genetic diversity in populations or the limitations of the markers used. Here we used microsatellite datasets for two sea grass species to provide a combinatory statistic, combined with a likelihood approach to estimate the probability of identical multilocus genotypes (MLGs) to be shared by distinct individuals, in order to ascertain the efficiency of the markers used and to optimize cost-efficiently the choice of markers to use for deriving unbiased estimates of genetic diversity. These results strongly indicate that conclusions from studies on clonal organisms derived using markers showing low polymorphism, including microsatellites, should be reassessed using appropriate polymorphic markers.     

Why are aggregates destroyed in low intensity fire?

Soil structure is often severely affected during high intensity burning, while low intensity prescribed burning has often been thought to have a low or neutral effect on soil aggregation. In this issue of Plant and Soil, (Albalasmeh et al. 2012) report a novel mechanism of aggregate disruption during low intensity burning that may explain some contradictory results reported in previous studies. Albalasmeh et al. (2012) suggest that during rapid heating of moist soil aggregates, intra-aggregate water is vaporized and the increased pressure causes rupture of the internal bonds and leads to aggregate breakdown. This mechanism can be compared to the aggregate breakdown due to slaking, when dry aggregates are suddenly wetted or submerged in water. Identification of the reasons for the aggregate disruption at low temperatures is important for choosing optimal soil and weather conditions for prescribed fires.     

Independent localization of MAP2, CaMKIIα and β-actin RNAs in low copy numbers

Messenger RNA localization involves the assembly of ribonucleoprotein particles (RNPs) and their subsequent transport along the cytoskeleton to their final destination. Here, we provide new evidence that microtubule-associated protein 2 (MAP2), calcium/calmodulin-dependent protein kinase II (CaMKIIα) and β-actin RNAs localize to dendrites in distinct RNPs, which contain--unexpectedly--very few RNA molecules. The number of MAP2 molecules per particle is affected by synaptic activity and Staufen 2, indicating that RNP composition is tightly controlled. Our data suggest that the independent localization of individual RNAs in low copy numbers could contribute to tighter temporal and spatial control of expression in neurons and synapse-specific plasticity.     

Evidence that αC region is origin of low modulus, high extensibility, and strain stiffening in fibrin fibers

Fibrin fibers form the structural scaffold of blood clots and perform the mechanical task of stemming blood flow. Several decades of investigation of fibrin fiber networks using macroscopic techniques have revealed remarkable mechanical properties. More recently, the microscopic origins of fibrin's mechanics have been probed through direct measurements on single fibrin fibers and individual fibrinogen molecules. Using a nanomanipulation system, we investigated the mechanical properties of individual fibrin fibers. The fibers were stretched with the atomic force microscope, and stress-versus-strain data was collected for fibers formed with and without ligation by the activated transglutaminase factor XIII (FXIIIa). We observed that ligation with FXIIIa nearly doubled the stiffness of the fibers. The stress-versus-strain behavior indicates that fibrin fibers exhibit properties similar to other elastomeric biopolymers. We propose a mechanical model that fits our observed force extension data, is consistent with the results of the ligation data, and suggests that the large observed extensibility in fibrin fibers is mediated by the natively unfolded regions of the molecule. Although some models attribute fibrin's force-versus-extension behavior to unfolding of structured regions within the monomer, our analysis argues that these models are inconsistent with the measured extensibility and elastic modulus.     

Specific activity of α-l-fucosidase in sera with phenotypes of either low,intermediate, or high total enzyme activity and in a fucosidosis serum

The quantity of -l-fucosidase activity in human serum is determined by heredity. An individual may inherit either low, intermediate, or high serum enzyme activity. An enzyme-linked immunoabsorbent assay has been developed that can detect 0.3 ng of -l-fucosidase protein. Enzyme protein in serum of 102 individuals ranged from 20 to 835 ng/ml. The group included individuals with low, intermediate, and high enzyme activity. The specific activity of -l-fucosidase within this group was statistically the same (mean±SD=11,002±1051 U/mg). Thus, individuals with low and intermediate enzyme activity in serum had lower amounts of enzyme protein with the same specific activity as in individuals with high enzyme activity. Fucosidosis is a rare inherited disease in which -l-fucosidase activity in tissues and body fluids is low or absent. The concentrations of enzyme protein in sera of a fucosidosis patient and parents were 76, 565, and 604 ng/ml, respectively, and the specific activities of enzyme were 1316, 8938, and 8858 U/mg, respectively. Thus, the fucosidosis serum probably contained a structurally altered enzyme with reduced catalytic activity. The somewhat low specific activities in the parents suggested that their sera contained both structurally altered and normal protein.This research was supported by National Institutes of Health Grants AM 32161 and GM 31425.     

Left–Right-Position,party affiliation and regional differences explain low COVID-19 vaccination rates in Germany

Established vaccine hesitancy measurement instruments, such as the Vaccine Hesitancy Determinants Matrix, are not sufficiently equipped to adequately and consistently measure political and ideological attitudes. Focusing on Germany, which is a particularly interesting case since it witnessed the establishment of the by far most well-organized and sustained ‘anti-Covid’ movement in Europe, this quantitative study explores the impact of political ideology and partisanship on the degree of vaccine hesitancy based on four surveys (February—October 2021) among more than 30,000 individuals. We demonstrate that party affiliation, political ideology and region of residence all impact vaccine hesitancy. In fact, they turn out to have a greater impact than two factors often analysed with respect to vaccine hesitancy: gender and educational background. Further interaction models show that the effect of political ideology on vaccine hesitancy is moderated by age, gender and region of residency. For instance, while the more rightwing a young individual is, the more hesitant they are towards SARS-CoV-2 vaccination—for older individuals, this is not the case. Our findings are relevant for future investigators measuring vaccine hesitancy and policy makers contemplating the differential impact of complex public health interventions: as the impact of political and ideological attitudes on vaccine hesitancy are not adequately captured by established vaccine hesitancy measurement instruments, we recommend its modification to include a clear and harmonised definition of the political-ideological dimension of vaccine hesitancy together with pre-validated measurement items that improve future studies. In addition, we reason that vaccine hesitancy, while being an outcome of complex socio-political factors, is in itself an indicator for societal cohesion and anomie, the degree of which is associated with trust in (health) policy makers, (public) health authorities, health service providers, etc. Therefore, we further recommend that vaccine hesitancy questions should be integrated in pertinent national surveys.     

Seed dispersal in an African fig tree: birds as high quantity,low quality dispersers?

Abstract. Ficus burtt-davyi is a shrub or small tree found in the south and east of South Africa. Based on studies carried out in an area where the plant grows mainly as a rock-splitter, we first describe the nature and timing of the fruit resources it offers to potential dispersal agents, and then the animals that feed on the fruits. The figs are eaten by a diverse avian disperser assemblage, although just two species comprised about half of the recorded visits to the trees. Germination trials with seeds defecated by the birds found that they germinated more quickly than control seeds. Small terrestrial mammals and ants were also found to have a role in fig seed dispersal which may be disproportionate to the number of seeds they transport.     

Safety, immunogenicity and dose ranging of a new Vi-CRM₁₉₇ conjugate vaccine against typhoid fever: randomized clinical testing in healthy adults

Background

Typhoid fever causes more than 21 million cases of disease and 200,000 deaths yearly worldwide, with more than 90% of the disease burden being reported from Asia. Epidemiological data show high disease incidence in young children and suggest that immunization programs should target children below two years of age: this is not possible with available vaccines. The Novartis Vaccines Institute for Global Health developed a conjugate vaccine (Vi-CRM₁₉₇) for infant vaccination concomitantly with EPI vaccines, either starting at 6 weeks with DTP or at 9 months with measles vaccine. We report the results from a Phase 1 and a Phase 2 dose ranging trial with Vi-CRM₁₉₇ in European adults.

Methodology

Following randomized blinded comparison of single vaccination with either Vi-CRM₁₉₇ or licensed polysaccharide vaccines (both containing 25·0 µg of Vi antigen), a randomised observer blinded dose ranging trial was performed in the same center to compare three concentrations of Vi-CRM₁₉₇ (1·25 µg, 5·0 µg and 12·5 µg of Vi antigen) with the polysaccharide vaccine.

Principal Findings

All vaccines were well tolerated. Compared to the polysaccharide vaccine, Vi-CRM₁₉₇ induced a higher incidence of mild to moderate short lasting local pain. All Vi-CRM₁₉₇ formulations induced higher Vi antibody levels compared to licensed control, with clear dose response relationship.

Conclusions

Vi-CRM₁₉₇ did not elicit safety concerns, was highly immunogenic and is therefore suitable for further clinical testing in endemic populations of South Asia.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT01123941","term_id":"NCT01123941"}}NCT01123941 {"type":"clinical-trial","attrs":{"text":"NCT01193907","term_id":"NCT01193907"}}NCT01193907     

Safety and immunogenicity of an MF59™-adjuvanted subunit influenza vaccine in elderly Chinese subjects

Background

The safety and immunogenicity of an MF59?-adjuvanted subunit influenza vaccine (Sub/MF59?; FLUAD^®, Novartis Vaccines) was evaluated among elderly Chinese subjects (≥ 60 years of age). After a preliminary Phase I, open-label study (n = 25) to assess safety 1–14 days post-vaccination, a comparative observer-blind, randomised, controlled clinical trial (n = 600) was performed to assess safety and immunogenicity versus a non-adjuvanted subunit influenza vaccine (Subunit; Agrippal^®, Novartis Vaccines). Subjects were randomised (2:1) to receive Sub/MF59? or Subunit.

Results

Both vaccines were well tolerated, with no vaccine-related serious adverse events reported during the Phase I trial. During the observer-blind study, local and systemic reactions were generally similar for both vaccines 1–22 days post-vaccination; however, injection-site induration was more frequent among the Subunit group (P < 0.05), and mild pain at the injection site and fever were more frequent among Sub/MF59? recipients (P ≤ 0.005). Both vaccines induced a significant (P < 0.001) increase in geometric mean titres (GMTs) for the three strains tested, versus baseline; GMTs against A/H1N1, A/H3N2 and B were significantly higher in the Sub/MF59? group (P = 0.034, P < 0.001 and P = 0.005, respectively). GMT ratios against A/H1N1, A/H3N2 and B were also significantly higher in the Sub/MF59? group (P = 0.038, P < 0.001 and P = 0.006, respectively). Similarly, the percentage of subjects achieving seroprotection or seroconversion on Day 22 was greater for Sub/MF59? recipients, reaching significance for A/H3N2 (P < 0.001).

Conclusion

MF59?-adjuvanted subunit influenza vaccine is well tolerated by elderly Chinese subjects and induces a higher level of immunogenicity than a non-adjuvanted subunit influenza vaccine in this population that is at high risk of influenza-related complications.

Clinical trial registry

http://www.clinicaltrials.gov, NCT00310648

     

Fisher's sons’ effect in sexual selection: absent,intermittent or just low experimental power?

The Fisherian sexual selection paradigm has been called the null model of sexual selection. At its heart is the expectation of a genetic correlation (r_G) between female preference and male trait. However, recent meta‐analysis has shown estimated correlations are often extremely weak and not statistically significant. We show here that systematic failure of studies to reject the null hypothesis that r_G = 0 is almost certainly due to the low power of most experimental designs used. We provide an easy way to assess experimental power a priori and suggest that current data make it difficult to definitively test a key component of the Fisher effect.     

Identification of a sub-micromolar,non-peptide inhibitor of β-secretase with low neural cytotoxicity through in silico screening

Nowadays identification of novel non-peptide β-secretase (BACE-1, hereinafter) inhibitors with low cytotoxicity and good blood–brain barrier (BBB) property holds common interest of drug discovery for Alzheimer’s disease. Twenty SPECS compounds were tested in BACE-1 FRET assays and methylthiazoletetrazolium (MTT) cytotoxicity experiment. Two compounds: 2 and 15 demonstrated IC₅₀ values of 0.53 and 9.4 μM. In addition, 2 showed least toxic effect to the neuroblastoma cells. The results from both in silico and in vitro studies provided new pharmacophoric entities for chemical synthesis and optimization on the current discovered BACE-1 small molecule inhibitors.     

Do spatial effects appear at low dilution rate in chemostat?

The chemostat theory on two species competition has shown that the dilution rate where transition of dominance occurs – transition-dilution rate – is independent of limiting-nutrient concentration. However, we obtained the experimental data indicating that the transition-dilution rate changed with variations in limiting-ammonium concentrations, using the chemostat mixed-culture of the cyanobacterium Microcystis novacekii and the green alga Scenedesmus quadricauda. The transition-dilution rate was dependent on the concentration of limiting ammonium in the influx culture medium. We tried to simulate the experimental results. Though the dilution rate has been considered independent of nutrient concentration, we introduce the effective dilution rate that depends on nutrient concentration (ammonium concentration in this study). A hyperbolic Monod-type function is used to represent the effective dilution rate for each species. The maximum dilution rate of the function is set to be the mechanical dilution rate (nominal dilution rate) of the chemostat culture. The calculation shows that the nominal transition-dilution rate where transition of dominance occur decreases with increased concentration. This simulation is well consistent with our experimental data. These results may suggest that the species-specificity of limiting nutrients, here nitrogen. Or they may imply that the depreciation of nitrogen becomes critical when both dilution rate and concentration are very low, especially for the green algae. In the latter case, spatial effects are induced internally in the ecosystem.     

Substrate activation in acetylcholinesterase induced by low pH or mutation in the π-cation subsite

Substrate inhibition is considered a defining property of acetylcholinesterase (AChE), whereas substrate activation is characteristic of butyrylcholinesterase (BuChE). To understand the mechanism of substrate inhibition, the pH dependence of acetylthiocholine hydrolysis by AChE was studied between pH 5 and 8. Wild-type human AChE and its mutants Y337G and Y337W, as well as wild-type Bungarus fasciatus AChE and its mutants Y333G, Y333A and Y333W were studied. The pH profile results were unexpected. Instead of substrate inhibition, wild-type AChE and all mutants showed substrate activation at low pH. At high pH, there was substrate inhibition for wild-type AChE and for the mutant with tryptophan in the π-cation subsite, but substrate activation for mutants containing small residues, glycine or alanine. This is particularly apparent in the B. fasciatus AChE. Thus a single amino acid substitution in the π-cation site, from the aromatic tyrosine of B. fasciatus AChE to the alanine of BuChE, caused AChE to behave like BuChE. Excess substrate binds to the peripheral anionic site (PAS) of AChE. The finding that AChE is activated by excess substrate supports the idea that binding of a second substrate molecule to the PAS induces a conformational change that reorganizes the active site.     

Alleviation of salt stress by low dose γ-irradiation in rice

The effects of salt stress on the growth, photosynthesis, and antioxidative ability of the rice (Oryza sativa L.) plants raising from -irradiated seeds were investigated using two cultivars, Ilpumbyeo and Sanghaehyanghyella. The 50 and 100 mM NaCl solutions caused a remarkable decrease of the early germination rate and seedling growth. However, the salt stress-induced inhibition of the growth was significantly alleviated in the -irradiated plants. The chlorophyll contents and the effective quantum yield of photosystem 2 ( _{PS 2}) were lower in the NaCl-treated plants than in the control ones, while the non-photochemical quenching was higher in the former ones. Activities of the antioxidant enzymes such as superoxide dismutase (SOD) and ascorbate peroxidase (APX) increased with increasing NaCl concentrations, and the irradiated groups had even higher SOD and APX activities than the non-irradiated ones. These alleviation effects were observed similarly in both the cultivars tested.