Pre-dawn infidelity: females control extra-pair mating in superb fairy-wrens

Despite great interest in the use of extra-pair mating as a tool for examining female choice and intersexual selection, the underlying assumption of female control has proved difficult to verify empirically. We combined microsatellite genotyping and radiotelemetry of fertile females in order to investigate mate choice in superb fairy-wrens Malurus cyaneus, the bird with the highest known rate of extra-pair fertilization. All five females radio tracked during the peak of fertility, two to four days before the first egg is laid, undertook pre-dawn forays. All extra-pair young produced by the female were sired by a male visited during their forays, indicating that females control extra-pair fertilizations. In a larger sample of paternity data, some broods were sired by two extra-group males. In virtually all the cases the territory of the two sires were on an identical linear trajectory from the female's territory. This again suggests that extra-group paternity in superb fairy-wrens is directly linked to female extra-territorial forays. In other species mixed paternity has been taken to indicate that females attempt to insure against infertile pairings or try to maximize the genetic diversity of their brood. However, in fairy-wrens the likelihood of multiple extra-group paternity increased greatly as females traversed more territories in order to mate, perhaps suggesting that females which foray further are more likely to have difficulties locating the preferred male.     

Systems analysis of primary Sjögren's syndrome pathogenesis in salivary glands identifies shared pathways in human and a mouse model

Bone tissue has an exceptional quality to regenerate to native tissue in response to injury. However, the fracture repair process requires mechanical stability or a viable biological microenvironment or both to ensure successful healing to native tissue. An improved understanding of the molecular and cellular events that occur during bone repair and remodeling has led to the development of biologic agents that can augment the biological microenvironment and enhance bone repair. Orthobiologics, including stem cells, osteoinductive growth factors, osteoconductive matrices, and anabolic agents, are available clinically for accelerating fracture repair and treatment of compromised bone repair situations like delayed unions and nonunions. Preclinical and clinical studies using biologic agents like recombinant bone morphogenetic proteins have demonstrated an efficacy similar or better than that of autologous bone graft in acute fracture healing. A lack of standardized outcome measures for comparison of biologic agents in clinical fracture repair trials, frequent off-label use, and a limited understanding of the biological activity of these agents at the bone repair site have limited their efficacy in clinical applications.     

MicroRNAs in systemic rheumatic diseases

MicroRNAs (miRNAs) are endogenous, non-coding, single-stranded RNAs about 21 nucleotides in length. miRNAs have been shown to regulate gene expression and thus influence a wide range of physiological and pathological processes. Moreover, they are detected in a variety of sources, including tissues, serum, and other body fluids, such as saliva. The role of miRNAs is evident in various malignant and nonmalignant diseases, and there is accumulating evidence also for an important role of miRNAs in systemic rheumatic diseases. Abnormal expression of miRNAs has been reported in autoimmune diseases, mainly in systemic lupus erythematosus and rheumatoid arthritis. miRNAs can be aberrantly expressed even in the different stages of disease progression, allowing miRNAs to be important biomarkers, to help understand the pathogenesis of the disease, and to monitor disease activity and effects of treatment. Different groups have demonstrated a link between miRNA expression and disease activity, as in the case of renal flares in lupus patients. Moreover, miRNAs are emerging as potential targets for new therapeutic strategies of autoimmune disorders. Taken together, recent data demonstrate that miRNAs can influence mechanisms involved in the pathogenesis, relapse, and specific organ involvement of autoimmune diseases. The ultimate goal is the identification of a miRNA target or targets that could be manipulated through specific therapies, aiming at activation or inhibition of specific miRNAs responsible for the development of disease.     

Frequent coexistence of anti-topoisomerase I and anti-U1RNP autoantibodies in African American patients associated with mild skin involvement: a retrospective clinical study

Introduction  

The presence of anti-topoisomerase I (topo I) antibodies is a classic scleroderma (SSc) marker presumably associated with a unique clinical subset. Here the clinical association of anti-topo I was reevaluated in unselected patients seen in a rheumatology clinic setting.     

Breaking the rules: sex roles and genetic mating system of the pheasant coucal

Generally in birds, the classic sex roles of male competition and female choice result in females providing most offspring care while males face uncertain parentage. In less than 5% of species, however, reversed courtship sex roles lead to predominantly male care and low extra-pair paternity. These role-reversed species usually have reversed sexual size dimorphism and polyandry, confirming that sexual selection acts most strongly on the sex with the smaller parental investment and accordingly higher potential reproductive rate. We used parentage analyses and observations from three field seasons to establish the social and genetic mating system of pheasant coucals, Centropus phasianinus, a tropical nesting cuckoo, where males are much smaller than females and provide most parental care. Pheasant coucals are socially monogamous and in this study males produced about 80% of calls in the dawn chorus, implying greater male sexual competition. Despite the substantial male investments, extra-pair paternity was unusually high for a socially monogamous, duetting species. Using two or more mismatches to determine extra-pair parentage, we found that 11 of 59 young (18.6%) in 10 of 21 broods (47.6%) were not sired by their putative father. Male incubation, starting early in the laying sequence, may give the female opportunity and reason to seek these extra-pair copulations. Monogamy, rather than the polyandry and sex-role reversal typical of its congener, C. grillii, may be the result of the large territory size, which could prevent females from monopolising multiple males. The pheasant coucal’s exceptional combination of classic sex-roles and male-biased care for extra-pair young is hard to reconcile with current sexual selection theory, but may represent an intermediate stage in the evolution of polyandry or an evolutionary remnant of polyandry.     

Heterokaryon formation and parasexual recombination between vegetatively incompatible lineages in a population of the chestnut blight fungus, Cryphonectria parasitica

Heterokaryosis was recently reported in the chestnut blight fungus, Cryphonectria parasitica, in which individuals contain nuclei that are isogenic except at the mating-type locus (MAT). MAT heterokaryons were found in several natural populations, including a putatively clonal population in West Salem, Wisconsin, providing an opportunity to address the question of how heterokaryons arise. We represented relationships among RFLP fingerprint haplotypes as networks in which loop formation is considered evidence of recombination. From 1990 to 1995, this population was clonal, as indicated by a simple haplotype network without loops, and the correlation of vegetative compatibility (vc) types and mating types with haplotype lineages. By 1999, we observed loops in the haplotype network involving isolates of two vc types (WS-2 and WS-3). Isolates with haplotypes in the loops were either MAT heterokaryons, carried the opposite mating type from other isolates of the same vc type, and/or had two alleles at two or more codominant SCAR (sequence-characterized amplified region) loci. Segregation of markers and recombination were evident among single-spore isolates from one heterokaryon; these single-spore isolates had novel fingerprint haplotypes, also within the loops. In contrast, vc type WS-1, which comprises 85% of the population, was represented by a simple network with no loops, indicating a clonal lineage varying only by mutation. Almost all isolates of WS-1 had the same mating type; the exceptions were five isolates that were MAT heterokaryons. These results are consistent with the hypothesis that heterokaryons formed between vegetatively incompatible individuals, and recombination occurred by a parasexual process.     

Species loss of stoneflies (Plecoptera) in the Czech Republic during the 20th century

1. Rapid expansion and intensification of anthropogenic activities in the 20th century has caused profound changes in freshwater assemblages. Unfortunately, knowledge of the extent and causes of species loss (SL) is limited due to the lack of reliable historical data. An unusual data set allows us to compare changes in the most sensitive of aquatic insect orders, the Plecoptera, at some 170 locations in the Czech Republic between two time periods, 1955–1960 and 2006–2010. Historical data (1890–1911) on assemblages of six lowland rivers allow us to infer even earlier changes. 2. Regional stonefly diversity decreased in the first half of the 20th century. Streams at lower altitudes lost a substantial number of species, which were never recovered. In the second half of the century, large‐scale anthropogenic pressure caused SL in all habitats, leading to a dissimilarity of contemporary and previous assemblages. The greatest changes were found at sites affected by organic pollution and a mixture of organic pollution and channelisation or impoundment. Colonisation of new habitats was observed in only three of the 80 species evaluated. 3. Species of moderate habitat specialisation and tolerance to organic pollution were most likely to be lost. Those with narrow specialisations in protected habitats were present in both historical and contemporary collections. 4. Contemporary assemblages are the consequence of more than a 100 years of anthropogenic impacts. In particular, streams at lower altitude and draining intensively exploited landscapes host a mere fragment of the original species complement. Most stonefly species are less frequently present than before, although their assemblages remain almost intact in near‐natural mountain streams. Our analyses demonstrate dramatic restriction of species ranges and, in some cases, apparent changes in altitudinal preference throughout the area.     

Activation of hypothalamic RIP‐Cre neurons promotes beiging of WAT via sympathetic nervous system

Activation of brown adipose tissue (BAT) and beige fat by cold increases energy expenditure. Although their activation is known to be differentially regulated in part by hypothalamus, the underlying neural pathways and populations remain poorly characterized. Here, we show that activation of rat‐insulin‐promoter‐Cre (RIP‐Cre) neurons in ventromedial hypothalamus (VMH) preferentially promotes recruitment of beige fat via a selective control of sympathetic nervous system (SNS) outflow to subcutaneous white adipose tissue (sWAT), but has no effect on BAT. Genetic ablation of APPL2 in RIP‐Cre neurons diminishes beiging in sWAT without affecting BAT, leading to cold intolerance and obesity in mice. Such defects are reversed by activation of RIP‐Cre neurons, inactivation of VMH AMPK, or treatment with a β3‐adrenergic receptor agonist. Hypothalamic APPL2 enhances neuronal activation in VMH RIP‐Cre neurons and raphe pallidus, thereby eliciting SNS outflow to sWAT and subsequent beiging. These data suggest that beige fat can be selectively activated by VMH RIP‐Cre neurons, in which the APPL2–AMPK signaling axis is crucial for this defending mechanism to cold and obesity.