Can overmarking be considered as a means of chemical mate guarding in a wild callitrichid?

Mate guarding is a male strategy to monopolize matings and thus to ensure paternity. Since in callitrichids female reproductive status is advertised by scent marks, one may expect mate guarding by chemical means. We addressed this question during an episode of consortship observed in a polyandrous trio of wild saddleback tamarins (Saguinus fuscicollis). During consortship, the consort male was the only one to allomark the female. Scent marking frequency decreased for all individuals, although the consort male marked more than the other male during consortship, while there was no difference in the previous period. During consortship, almost 50% of female scents were overmarked by the consort, and more than 56% of the consort's scent marks were employed to overmark the female's scents. Therefore, the other male had limited access to female scent marks. Mate guarding may thus have a chemical component in tamarins, and olfactory communication may play an important role in mating competition.     

Community genetics: what have we accomplished and where should we be going?

Research in community genetics seeks to understand how the dynamic interplay between ecology and evolution shapes simple and complex communities and ecosystems. A community genetics perspective, however, may not be necessary or informative for all studies and systems. To better understand when and how intraspecific genetic variation and microevolution are important in community and ecosystem ecology, we suggest future research should focus on three areas: (i) determining the relative importance of intraspecific genetic variation compared with other ecological factors in mediating community and ecosystem properties; (ii) understanding the importance of microevolution in shaping ecological dynamics in multi-trophic communities; and (iii) deciphering the phenotypic and associated genetic mechanisms that drive community and ecosystem processes. Here, we identify key areas of research that will increase our understanding of the ecology and evolution of complex communities but that are currently missing in community genetics. We then suggest experiments designed to meet these current gaps.     

Is increased juvenile infection the key to recovery of wild rabbit populations from the impact of rabbit haemorrhagic disease?

The frequency and timing of rabbit haemorrhagic disease (RHD) epizootics and their impact on different age groups of rabbits were studied for 15 years in a recovering rabbit population in South Australia. We recorded the number and body size of rabbits dying during RHD epizootics, collected tissue for genetic analysis of rabbit haemorrhagic disease virus variants and compared the number of carcasses found to the number of susceptible rabbits present at the beginning of each epizootic. All RHD epizootics occurred between late winter and spring, but, progressively, epizootics started earlier and became more frequent and prolonged, fewer susceptible adult rabbits were present during epizootics, and the age of rabbits dying of RHD declined. Increased infection and virus shedding in juvenile rabbits offers the most plausible explanation for those epidemiological changes; the disease is now increasingly transmitted through populations of kittens, starting before young-of-the-year reach adult size and persisting late in the breeding season, so that most rabbits are challenged in their year of birth. These changes have increased juvenile mortality due to RHD but reduced total mortality across all age groups, because age-specific mortality rates are lower in young rabbits than in older rabbits. We hypothesise that this may be the proximate cause of recovery in rabbit populations across Australia and possibly elsewhere.     

Cryopreservation of threatened native Australian species—what have we learned and where to from here?

Cryogenic storage techniques have been developed and adopted for more than 100 (mainly agricultural) plant species worldwide, and within Australia, at least 30 critically endangered plants have been stored long term using cryogenic approaches. Nevertheless, there are many species that are very difficult to store using current procedures, and organizations involved in plant germplasm conservation (such as botanic gardens, agricultural institutions, etc.) that utilise cryogenic storage techniques are in some respects at a crossroads in their endeavours to cheaply and effectively store a wide selection of species and genotypes for conservation and agricultural/horticultural purposes. For taxa that are not amenable to current cryogenic approaches, new ways of developing cryogenic storage techniques need to be investigated, including research into the ways in which cell membranes interact and change when cooled to cryogenic temperatures (−196°C in liquid nitrogen) in the presence of various cryoprotective agents. This review highlights the current state of cryogenic research both within Australia and internationally, provides a case study on threatened plant species and also describes several new research initiatives that aim to provide answers to why some native species are quite amenable to widely utilised cryogenic approaches whilst others are currently non-responsive. New approaches aim to integrate laboratory and membrane modelling paradigms to provide guidelines for the development of new cryopreservation protocols and to assess the robustness of theoretical models in predicting optimum cryogenic conditions.     

Invasive trees and shrubs: where do they come from and what we should expect in the future?

The global database of invasive trees and shrubs has been updated, resulting in a total of 751 species (434 trees and 317 shrubs) from 90 families (Rejmánek and Richardson 2013 Divers Distrib 19:1093–1094). This database is used to assess major trends in human-assisted exchanges of dendrofloras among 15 major geographical regions. Areas most invaded by non-native trees are Pacific Islands (136 species), Southern Africa (118), Australia (116), and North America (114). Areas most invaded by non-native shrubs are North America (98), Australia (87), Pacific Islands (71), and Europe (61). The most important sources of invasive trees are Asia (122–146 species, depending on how many Eurasian species are considered to have been introduced only from Europe), Australia (81), and South America (81). The most important sources of invasive shrubs are Asia (103–118), Europe (68), and South America (54). Mean number of native geographical regions for invasive trees is 1.64, while the mean number of invaded regions by trees is 2.51. The difference is smaller for shrubs: 1.60 versus 2.11. Asia is the major source of invasive Rosaceae shrubs, as well as invasive Arecaceae and Oleaceae species. South America and Australia are major sources of invasive Fabaceae trees. North America and Europe are major sources of invasive Pinaceae. Most of the invasive Salicaceae are of Eurasian origin. The identified trends will very likely continue in this century. Because of increasing interactions with many states in Asia, even more invasive woody species will be introduced from this part of the world.     

Pulmonary and renal pressure-flow relationships: what should be taught?

This article is from a symposium presented at the annual meeting of the Human Anatomy and Physiology Society (HAPS) on June 11, 2000. The presentation was funded under the auspices of a National Science Foundation Course, Curriculum, and Laboratory Improvement Program entitled "Development of Active Learning Materials for Physiology and Functional Anatomy: A Cooperative HAPS-APS Initiative." This symposium was part of the first module to be developed on "gradients and conductances: what flows where and why?" This presentation was designed to model the usefulness of the general model of gradients and conductances in the physiology and pathophysiology of the respiratory and renal systems. Thirteen different examples of pressure-flow-resistance and concentration-flux relationships are introduced; several ideas for active-learning activities and simple figures appropriate for undergraduate physiology classes are included. The symposium assumes that undergraduate students have already learned about diffusion, osmosis, and the basic principles of cardiovascular physiology. The presentation was designed to follow a symposium entitled: "Cardiovascular pressure-flow relationships: what should be taught?"     

Tachinid parasitoids: are they to be considered as koinobionts?

Tachinids are usually considered as koinobionts as none of them kills or paralyzes the host when first entering it. These parasitoids, however, do not fit well into the koinobiont/idiobiont dichotomy because only some species show a high degree of physiological adaptation to the host, whereas the larvae of other species grow quickly following attack and kill the host rapidly, thus behaving more as idiobionts. The in vitro rearing technique provides further evidence for the poor adequacy of the koinobiont/idiobiont dichotomy for tachinids. In fact, while typical koinobionts are known to be difficult to culture on artificial media, some tachinids displaying non-synchronized development with the host have been successfully reared in vitro on insect material-free artificial media, thus behaving similarly to idiobionts. I therefore suggest not to use the koinobiont/idiobiont classification for tachinids and to class them instead only on the basis of the presence or absence of developmental synchrony with their hosts.     

Beta-arrestins as regulators of signal termination and transduction: how do they determine what to scaffold?

Over the last decade β-arrestins have emerged as pleiotropic scaffold proteins, capable of mediating numerous diverse responses to multiple agonists. Most well characterized are the G-protein-coupled receptor (GPCR) stimulated β-arrestin signals, which are sometimes synergistic with, and sometimes independent of, heterotrimeric G-protein signals. β-arrestin signaling involves the recruitment of downstream signaling moieties to β-arrestins; in many cases specific sites of interaction between β-arrestins and the downstream target have been identified. As more information unfolds about the nature of β-arrestin scaffolding interactions, it is evident that these proteins are capable of adopting multiple conformations which in turn reveal a specific set of interacting domains. Recruitment of β-arrestin to a specific GPCR can promote formation of a specific subset of available β-arrestin scaffolds, allowing for a higher level of specificity to given agonists. This review discusses recent advances in β-arrestin signaling, discussing the molecular details of a subset of known β-arrestin scaffolds and the significance of specific binding interactions on the ultimate cellular response.     

Phenylphenalenone phytoalexins, will they be a new type of fungicide?

Phenylphenalenones represent a kind of phytoalexins produced in leaves and rhyzomes of banana and plantains (Musaceae), as well as in species of other families. These compounds are synthesized in plants by induction with aminoglycosides, or in the first stages of attack by the pathogenic fungus Mycosphaerella fijensis, a causal agent of the disease known as Black Sigatoka, which reduces banana production. In this paper we report the biosynthesis, synthesis and antifungal activities of these kinds of compounds and discus the possibility to use phytoalexins inductors as plant protectants.     

Cancer of the lung: what should be the present approach?

The best opportunities at present for improving the results in the treatment of patients with cancer of the lung are by way of (a) utilizing the information obtained on routine x-ray examination of the chest, (b) decreasing the delay between the time of the first symptoms and the time the patient consults a physician, and (c) decreasing the delay between the time the patient first consults a physician and the time the cancer is surgically removed. The medical profession must increase its index of suspicion of cancer of the lung and persist in efforts to make a diagnosis when lung cancer is suspected. Exploratory thoracotomy should be used in suspicious cases when the diagnosis cannot be established by other methods.     

Investigating physiological changes in the aerial parts of AM plants: what do we know and where should we be heading?

Research in the field of arbuscular mycorrhizal (AM) symbiosis has taken a giant leap in the past two decades, as demonstrated by the large amount of literature being published every year. Most of the research efforts have been put towards the understanding of the mechanisms of this symbiosis. However, there are still several unknowns on the systemic effects of the AM symbiosis, and our understanding of non-nutritional effects on the physiological changes occurring in the aerial parts of the host plant is yet quite limited. In this short note, I briefly address the question, if there are any changes in metabolic activities that are triggered by AM fungi, and assess the importance of such changes for mycorrhizal research and application.     

The point of no return: Up to what point should we be allowed to withdraw consent to the storage and use of embryos and gametes?

This article discusses when it is ethically acceptable to withdraw consent for the storage and use of embryos and gametes. Currently, the law in the UK states that consent to use of a gamete or embryo can be withdrawn up to the point of the embryo's transfer to the recipient's uterus or when the gamete is used in providing treatment services; that is, the ‘point of no return’. In this article, we will consider other points of no return and argue that having a single point of no return, a one size fits all form of consent can, in some cases, lead to restrictions on individuals’ autonomy and cause particular types of harm. Therefore, having different points of no return that fit different circumstances could extend autonomy and allow people to enter into agreements that are tailored more to their own particular needs and circumstances.     

Mild stress as a means to modulate aging: from fly to human?

Hormesis is the phenomenon by which adaptive responses to low doses of otherwise harmful conditions improve the functional ability of organisms. Some mild stresses have beneficial effects on longevity, aging and resistance to strong stresses (heat or cold shocks, infection) in Drosophila flies. Studies on rodents are indeed scarce but mild stress seems to be effective in humans because, for instance, patients suffering from angina have a higher survival when confronted with a heart attack. A few studies, in less tragic situations however, suggest that mild stress could have positive effects in elderly people. Performing more experiments on the effects of mild stress in humans would help to know whether it could be used in therapy or to improve healthspan of elderly.     

Debate: at what level of coronary heart disease risk should a statin be prescribed?

3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) are effective treatments for the primary and secondary prevention of coronary heart disease, but an outstanding issue is determining who should have such treatment. The benefit from treatment with statins appears to be proportional to the underlying risk of coronary heart disease and independent of the factors increasing risk. Most benefit will therefore be achieved by treating people at increased risk of coronary heart disease. Statins reduce coronary morbidity even when the risk of coronary heart disease is relatively low (6% over 10 years), but reduction in all-cause mortality, the true measure of safety has been shown only when the risk of a major coronary heart disease event is 15% over 10 years or greater. At this level of risk patients appear willing to take treatment to gain the benefit expected from statin treatment, and the cost effectiveness of statin treatment is within the range accepted for other treatments. The major impediments to the systematic introduction of statin treatment at this level of risk are the very high overall cost and the large workload in countries like Britain, where the population risk of coronary heart disease is high. For this reason, recent British guidelines correctly advise statin treatment for secondary prevention and primary prevention when the 10 year coronary heart disease risk is 30% or greater as the first priority, moving to a lower coronary heart disease threshold for primary prevention only when resources permit.