Avian Influenza Ecology in North Atlantic Sea Ducks: Not All Ducks Are Created Equal

Wild waterfowl are primary reservoirs of avian influenza viruses (AIV). However the role of sea ducks in the ecology of avian influenza, and how that role differs from freshwater ducks, has not been examined. We obtained and analyzed sera from North Atlantic sea ducks and determined the seroprevalence in those populations. We also tested swab samples from North Atlantic sea ducks for the presence of AIV. We found relatively high serological prevalence (61%) in these sea duck populations but low virus prevalence (0.3%). Using these data we estimated that an antibody half-life of 141 weeks (3.2 years) would be required to attain these prevalences. These findings are much different than what is known in freshwater waterfowl and have implications for surveillance efforts, AIV in marine environments, and the roles of sea ducks and other long-lived waterfowl in avian influenza ecology.     

Not All Offspring Are Created Equal: Variation in Larval Characteristics in a Serially Spawning Damselfish

The way organisms allocate their resources to growth and reproduction are key attributes differentiating life histories. Many organisms spawn multiple times in a breeding season, but few studies have investigated the impact of serial spawning on reproductive allocation. This study investigated whether resource allocation was influenced by parental characteristics and prior spawning history in a serial spawning tropical damselfish (Pomacentrus amboinensis). The offspring attributes of isolated parents of known characteristics were monitored over a 6-week breeding period in the field. Smaller females produced larvae of longer length and larger energy reserves at hatching. This finding is contrary to several other studies that found larger females produce offspring of greater quality. We found that resource allocation in the form of reproductive output was not influenced by the number of spawning events within the breeding season, with larger females producing the greatest number of offspring. Larval characteristics changed as spawning progressed. There was a general decline in length of larvae produced, with an increase in the size of the larval yolk-sac, for all females regardless of size as spawning progressed. This trend was accentuated by the smallest females. This change in larval characteristics may reflect a parental ability to forecast unfavourable conditions as the season progresses or a mechanism to ensure that some will survive no matter what conditions they encounter. This study highlights the importance of accounting for temporal changes in reproductive allocation in studies of reproductive trade-offs and investigations into the importance of parental effects.     

Telomere Length Profiles in Humans: All Ends are Not Equal

Telomere length is an important parameter of telomere function since it determines number of aspects controlling chromosome stability and cell division. Since telomeres shorten with age in humans and premature aging syndromes are often associated with the presence of short telomeres, it has been proposed that telomere length is also an important parameter for organismal aging. How mean telomere lengths are determined in humans remains puzzling, but it is clear that genetic and epigenetic factors appear to be of great importance. Experimental evidence obtained from many different organisms has provided the basis for a widely accepted counting mechanism based on a negative feedback loop for telomerase activity at the level of individual telomeres. In addition, recent studies in both normal and pathological contexts point to the existence of chromosome-specific mechanisms of telomere length regulation determining a telomere length profile, which is inherited and maintained throughout life. In this review, we recapitulate the available data, propose a synthetic view of telomere length control mechanisms in humans and suggest new approaches to test current hypotheses.     

All SNPs Are Not Created Equal: Genome-Wide Association Studies Reveal a Consistent Pattern of Enrichment among Functionally Annotated SNPs

Recent results indicate that genome-wide association studies (GWAS) have the potential to explain much of the heritability of common complex phenotypes, but methods are lacking to reliably identify the remaining associated single nucleotide polymorphisms (SNPs). We applied stratified False Discovery Rate (sFDR) methods to leverage genic enrichment in GWAS summary statistics data to uncover new loci likely to replicate in independent samples. Specifically, we use linkage disequilibrium-weighted annotations for each SNP in combination with nominal p-values to estimate the True Discovery Rate (TDR = 1−FDR) for strata determined by different genic categories. We show a consistent pattern of enrichment of polygenic effects in specific annotation categories across diverse phenotypes, with the greatest enrichment for SNPs tagging regulatory and coding genic elements, little enrichment in introns, and negative enrichment for intergenic SNPs. Stratified enrichment directly leads to increased TDR for a given p-value, mirrored by increased replication rates in independent samples. We show this in independent Crohn''s disease GWAS, where we find a hundredfold variation in replication rate across genic categories. Applying a well-established sFDR methodology we demonstrate the utility of stratification for improving power of GWAS in complex phenotypes, with increased rejection rates from 20% in height to 300% in schizophrenia with traditional FDR and sFDR both fixed at 0.05. Our analyses demonstrate an inherent stratification among GWAS SNPs with important conceptual implications that can be leveraged by statistical methods to improve the discovery of loci.     

Detection of Differential Host Susceptibility to the Marine Oomycete Pathogen Eurychasma dicksonii by Real-Time PCR: Not All Algae Are Equal

In the marine environment, a growing body of evidence points to parasites as key players in the control of population dynamics and overall ecosystem structure. However, their prevalence and impact on marine macroalgal communities remain virtually unknown. Indeed, infectious diseases of seaweeds are largely underdocumented, partly because of the expertise required to diagnose them with a microscope. Over the last few years, however, real-time quantitative PCR (qPCR) has emerged as a rapid and reliable alternative to visual symptom scoring for monitoring pathogens. Thus, we present here a qPCR assay suitable for the detection and quantification of the intracellular oomycete pathogen Eurychasma dicksonii in its ectocarpalean and laminarialean brown algal hosts. qPCR and microscopic observations made of laboratory-controlled cultures revealed that clonal brown algal strains exhibit different levels of resistance against Eurychasma, ranging from high susceptibility to complete absence of symptoms. This observation strongly argues for the existence of a genetic determinism for disease resistance in brown algae, which would have broad implications for the dynamics and genetic structure of natural populations. We also used qPCR for the rapid detection of Eurychasma in filamentous brown algae collected in Northern Europe and South America and found that the assay is specific, robust, and widely applicable to field samples. Hence, this study opens the perspective of combining large-scale disease monitoring in the field with laboratory-controlled experiments on the genome model seaweed Ectocarpus siliculosus to improve our understanding of brown algal diseases.     

Not All Signals are Equal: Male Brown Anole Lizards (Anolis sagrei) Selectively Decrease Pushup Frequency Following a Simulated Predatory Attack

The use of conspicuous communication signals often increases a signaler's risk of predation. Many species communicate with a repertoire of signals that may differ in their conspicuousness to predators. Few studies have examined the ability of prey to selectively decrease the use of individual signals in their displays under heightened predation risk. Here, I examined the behavior of male brown anole lizards (Anolis sagrei) in response to a simulated predatory attack from a model kestrel. This species communicates with three major visual signal types, the head‐bob, pushup, and dewlap extension, which vary in their motion and spectral characteristics. I predicted that lizards would decrease frequencies of the dewlap extension and pushup following the attack, but not the head‐bob. Males modulated their use of individual signals by decreasing pushup rates, but not head‐bob rates. Decreases in dewlap frequency were marginally significant. One explanation for these results is that lizards decrease frequencies of signal types based partly on their conspicuousness. The energetic cost of each signal type may be an equally important factor that determines the signaler's response to predators, particularly if a predatory attack is perceived as imminent.     

Not All Bethesda 1 Thyroid Nodules Were Created Equal: Different B1 Subgroups

ObjectiveThe Bethesda System for Reporting Thyroid Cytopathology is a uniform method used worldwide to report thyroid fine-needle aspiration (FNA) outcomes. This study focuses on the Nondiagnostic/Unsatisfactory category, designated as Bethesda1 (B1). The documented risk of malignancy for B1 nodules can vary significantly, implying this category is not homogenous and might be composed of different subtypes. Our hypothesis was that B1 subgroups (blood only, insufficient thyrocytes, cyst content) will vary in their malignancy rate.MethodsThe study design was observational and retrospective. The study population included 154 patients in the Galilee Medical Center who underwent FNA examination of the thyroid gland from 2013-2018 and had a B1 result. We looked at the final diagnosis of malignant or benign for patients who underwent surgery and calculated the malignancy rate for each subgroup.ResultsMalignancy rates were higher in the Blood subgroup than in the other subgroups, and higher in the Thyrocytes subgroup than in the Cyst subgroup (P < .05). All malignancies were papillary thyroid carcinomas. There was no significant difference in the malignancy rate when we further divided the B1 samples into 2 groups based on the presence of epithelial cells. Many repeat FNA tests resulted in a different B1 subgroup.ConclusionThe different malignancy rates suggest that individual management approaches should be considered for each B1 subgroup.     

Human Islet Morphology Revisited: Human and Rodent Islets Are Not So Different After All

There has been great interest in understanding how human islets differ from rodent islets. Three major issues about human islet morphology have remained controversial over recent decades: 1) the proportion of the islet made up of β-cells; 2) whether islet cell types have a non-random mantle-core pattern, as seen in rodents, or are randomly scattered throughout the islet; 3) the relation of the different cell types to the blood vessels within the islet, which has implications for intraislet function. We re-examined these issues on immunostained sections of non-diabetic adult human pancreas. The composition of the islets can vary by the analysis method (number vs volume) and by the sampling of islets by size. The majority of adult human islets have clear, non-random clustering of β-cells and blood vessels that penetrate into the β-cell cores. We conclude that although there is far more variability in islet composition both within each human pancreas and among different human pancreas than in rodent pancreas, the islet architecture is not so different between the species. The intrapancreatic variability raises important questions about how islets evolve and function throughout life and how this might relate to the pathogenesis of diabetes.     

Drugs Are Not Enough: Some Principles of Psychopharmacology for General Medical Practice

There is no necessary antagonism between the judicious use of drugs and a psychotherapeutic approach to patients in general medical practice. A table is presented with a simple pragmatic classification of types of drugs for altering emotional and mental states. Three general principles are given for the use of such drugs, illustrated by examples of the use and misuse of tranquillizers.Some differentiation is made between sedatives and tranquillizers and between different types of tranquillizers, particularly with reference to the need to consider depressive features in patients. Suggestions are made for the use of drugs for mild depressions and for depressions accompanying organic disease.One may have to take an “experimental” approach to new drugs to determine which to them are of value in relation to the particular emotional states of one''s own patients.     

A Ewing's Sarcoma Cell Line Showing Some, but Not All, of the Traits of a Cholinergic Neuron

Abstract: The Ewing's sarcoma cell line ICB 112 was examined in detail for a cholinergic phenotype. Choline acetyltransferase activity (12.3 ± 2.9 nmol/h/mg of protein) was associated with the presence of multiple mRNA species labeled with a human choline acetyltransferase riboprobe. Choline was taken up by the cells by a high-affinity, hemicholinium-3-sensitive transporter that was partially inhibited when lithium replaced sodium in the incubation medium; the choline taken up was quickly incorporated into both acetylcholine and phosphorylcholine. High-affinity binding sites for vesamicol, an inhibitor of vesicular acetylcholine transport, were also present. The mRNAs for synaptotagmin (p65) and the 15-kDa proteolipid were readily detected and were identical in size to those observed in cholinergic regions of the human brain. Cumulative acetylcholine efflux was increased by raising the extracellular potassium level or the addition of a calcium ionophore, but the time course of stimulated efflux was slow and persistent. These results show that this morphologically undifferentiated cell line is capable of acetylcholine synthesis and expresses markers for synaptic vesicles as well as proteins implicated in calcium-dependent release but lacks an organized release mechanism.     

Tracking Changing Environments: Innovators Are Fast,but Not Flexible Learners

Behavioural innovations are increasingly thought to provide a rich source of phenotypic plasticity and evolutionary change. Innovation propensity shows substantial variation across avian taxa and provides an adaptive mechanism by which behaviour is flexibly adjusted to changing environmental conditions. Here, we tested for the first time the prediction that inter-individual variation in innovation propensity is equally a measure of behavioural flexibility. We used Indian mynas, Sturnus tristis, a highly successful worldwide invader. Results revealed that mynas that solved an extractive foraging task more quickly learnt to discriminate between a cue that predicted food, and one that did not more quickly. However, fast innovators were slower to change their behaviour when the significance of the food cues changed. This unexpected finding appears at odds with the well-established view that avian taxa with larger brains relative to their body size, and therefore greater neural processing power, are both faster, and more flexible learners. We speculate that the existence of this relationship across taxa can be reconciled with its absence within species by assuming that fast, innovative learners and non innovative, slow, flexible learners constitute two separate individual strategies, which are both underpinned by enhanced neural processing power. This idea is consistent with the recent proposal that individuals may differ consistently in ‘cognitive style’, differentially trading off speed against accuracy in cognitive tasks.     

Fruit,Minerals, and Forest Elephant Trails: Do All Roads Lead to Rome?

Tropical forests are among the most heterogeneous environments on earth, and food resources for many animals are patchy both in time and space. In Africa's equatorial forest, permanent trails created and maintained by forest elephants are conspicuous features. Trails may be several meters wide and continue for tens of kilometers. Speculation on which resources determine the distribution of trails has identified fruit, browse, and mineral deposits as candidates. In this study, the relationships between these habitat variables and elephant trails were investigated. The size of individual trails and the density of the trail system increased dramatically with proximity to mineral deposits. Fruit tree basal area decreased with perpendicular distance from trails, while that of non‐fruit trees did not. Fruit tree abundance and basal area were significantly higher on trail intersections than random sites and increased with intersection size. No relationship was found between monocotyledon browse abundance and elephant trail system characteristics. Clumped resources, which are at least partially reliable, provide a high nutritional payback, and are not rapidly depleted and can thus be visited repeatedly, appear to influence permanent trail formation by forest elephants. Permanent trails may allow naive individuals or those with imperfect knowledge to locate and acquire important resources.