Vitiligo: Where Do We Stand?

Vitiligo is a puzzling disorder characterized by a disappearance of epidermal and/or follicular melanocytes by unknown mechanisms. This very common disorder involving 1–4% of the world population is thus of great importance for the practicing dermatologist. The cellular and molecular mechanisms leading to the destruction of melanocytes in this disorder have not yet been elucidated, making it of major interest for the cell biologist involved in melanocyte research. Recent advances in this field, due largely to the availability of techniques for culturing normal human melanocytes, opened new perspectives in the understanding of vitiligo. Although vitiligo has long been considered a disorder confined to the skin, there is now good evidence that it also involves the extracutaneous compartment of the “melanocyte organ.” It is also clear that vitiligo is not only a melanocyte disorder, but that it also involves cells, such as keratinocytes and Langerhans cells, found in the epidermis and follicular epithelium. The three prevailing theories of the pathogenesis of vitiligo are the immune hypothesis, the neural hypothesis, and the self-destruct hypothesis. New hypotheses suggest that vitiligo may be due to (1) a deficiency in an unidentified melanocyte growth factor, (2) an intrinsic defect of the structure and function of the rough endoplasmic reticulum in vitiligo melanocytes, (3) abnormalities in a putative melatonin receptor on melanocytes and (4) a breakdown in free radical defense in the epidermis. None of these hypotheses has been demonstrated, and according to the available data, it is likely that the loss of epidermal and follicular melanocytes in vitiligo may be the result of several different pathogenetic mechanisms.     

Do We Practice What We Preach? Goal Setting for Ecological Restoration

Over the last decade, several research and opinion pieces have challenged the tenets of restoration ecology but a lack of centralized data has impeded assessment of how scientific developments relate to on‐the‐ground restoration. In response, the Society for Ecological Restoration (SER) launched the Global Restoration Network (GRN) to catalog worldwide restoration efforts. We reviewed over 200 GRN projects to identify the goals governing restoration and the frequency with which they are measured. We used the SER Primer on Ecological Restoration to frame our analysis, categorizing goals by SER's attributes of restored ecosystems. We developed additional attributes to characterize goals not encompassed by the SER‐defined attributes. Nearly all projects included goals related to ecosystem form, namely similarity to reference conditions and the presence of indigenous species, and these goals were frequently measured. Most projects included goals related to ecosystem function, and many highlighted interactions between abiotic and biotic factors by either modifying abiotic conditions to support focal species or manipulating species to achieve desired ecosystem functions. Few projects had goals related to ecosystem stability, whereas the majority of projects had goals related to social values. Although less frequently measured, social goals were described as important for long‐term project success. In conclusion, science and practice frequently aligned on goals related to ecosystem composition and function, but scientific guidelines on resilience and self‐sustainability appear insufficient to guide practice. In contrast, the common inclusion of goals for human well‐being indicates that, if intended to advise practice, restoration guidelines should give direction on social goals.     

Mangrove Restoration: Do We Know Enough?

Mangrove restoration projects have been attempted, with mixed results, throughout the world. In this paper, I first examine goals of existing mangrove restoration projects and determine whether these goals are clear and adequate, and whether or not they account for the full range of biological diversity and ecological processes of mangrove ecosystems. Many restored mangrove forests resemble forest plantations rather than truly integrated ecosystems, but mangrove plantations can be a first step toward mangrove rehabilitation. Mangrove restoration projects that involve associated aquaculture or mariculture operations tend to be more likely to approximate the biological diversity and ecological processes of undisturbed mangrove ecosystems than are projects that focus only on the trees. These integrated restoration projects also provide a higher economic return than do silvicultural projects alone. Second, I briefly assess whether existing ecological data are sufficient to undergird successful restoration of mangal and define criteria for determining whether or not a mangrove ecosystem has been restored successfully. These criteria include characteristics of vegetation (forest) structure, levels of primary production, composition of associated animal communities, and hydrology. Finally, I suggest ways to improve mangrove restoration projects and identify key research needs required to support these efforts. Ecological theories derived from other wetland and upland systems rarely have been applied to either “basic” or “applied” mangrove forest studies, to the detriment of restoration projects, whereas lessons from restoration of the relatively species‐poor mangrove ecosystems could be beneficially applied to restoration projects in other contexts. An international database of mangrove restoration projects would reduce the likelihood that unsuccessful restoration projects would be repeated elsewhere. Clear criteria for evaluating success, greater accessibility of information by managers in the developing world, intensified international cooperation, and application of relevant ecological theories will improve the success rate of mangrove restoration projects.     

Vaccines against Tuberculosis: Where Are We and Where Do We Need to Go?

In this review we discuss recent progress in the development, testing, and clinical evaluation of new vaccines against tuberculosis (TB). Over the last 20 years, tremendous progress has been made in TB vaccine research and development: from a pipeline virtually empty of new TB candidate vaccines in the early 1990s, to an era in which a dozen novel TB vaccine candidates have been and are being evaluated in human clinical trials. In addition, innovative approaches are being pursued to further improve existing vaccines, as well as discover new ones. Thus, there is good reason for optimism in the field of TB vaccines that it will be possible to develop better vaccines than BCG, which is still the only vaccine available against TB.     

Replication Origins: Why Do We Need So Many?

During the G1 phase of the cell cycle, replication origins are prepared to fire, a process that is referred to as origin licensing. It was often pondered what a cell’s fate would be if not all of its replication origins were licensed and subsequently activated during S phase. One obvious prediction was that S phase would simply be prolonged. As it turns out, however, the consequences are much more complex. A short G1 phase enforced by premature entry into S phase, or other events that negatively affect origin licensing, will ultimately compromise the cell’s ability to complete DNA replication before entering mitosis. As a result, the cell becomes genomically unstable when it attempts to repair unreplicated DNA during anaphase. Thus, the density of active replication origins in the chromosomes of eukaryotic cells determines S phase dynamics and chromosome stability during mitosis.     

From Habits to Self-Regulation: How Do We Change?

The Yale Cognitive Science department hosted the conference “From Habits to Self-Regulation: How Do We Change?” on November 4 and 5, 2011, to showcase current research on self-control in cognitive science, psychology, and neuroscience. The conference included a panel discussion by four philosophers who gave context for the scope and limitations of research on self-control. The common theme concerning the best method to attain lasting change included becoming aware of what one wants to change, increasing commitment to the goal of change, and imagining all of the potential problems and solutions to those problems.     

Characterizing Protease Specificity: How Many Substrates Do We Need?

Calculation of cleavage entropies allows to quantify, map and compare protease substrate specificity by an information entropy based approach. The metric intrinsically depends on the number of experimentally determined substrates (data points). Thus a statistical analysis of its numerical stability is crucial to estimate the systematic error made by estimating specificity based on a limited number of substrates. In this contribution, we show the mathematical basis for estimating the uncertainty in cleavage entropies. Sets of cleavage entropies are calculated using experimental cleavage data and modeled extreme cases. By analyzing the underlying mathematics and applying statistical tools, a linear dependence of the metric in respect to 1/n was found. This allows us to extrapolate the values to an infinite number of samples and to estimate the errors. Analyzing the errors, a minimum number of 30 substrates was found to be necessary to characterize substrate specificity, in terms of amino acid variability, for a protease (S4-S4’) with an uncertainty of 5 percent. Therefore, we encourage experimental researchers in the protease field to record specificity profiles of novel proteases aiming to identify at least 30 peptide substrates of maximum sequence diversity. We expect a full characterization of protease specificity helpful to rationalize biological functions of proteases and to assist rational drug design.     

Why Do We Expect Carotenoids to be Antioxidants in vivo?

The antioxidant properties of β-carotene, in addition to its proposed immunomodulatory effects, have often been cited as the factors underlying its role in preventing disease initiation and propagation, yet the strongest evidence for diet and cancer prevention is based on fruit and vegetable intake and not β-carotene or other dietary carotenoids, per se. In the light of the outcome of the ATBC trial, the Physicians Health Study and the premature termination of the CARET study, this review addresses the issue of the antioxidant properties of the carotenoids and poses the questions: do dietary carotenes and xanthophylls have a clear role in disease prevention and are their antioxidant properties relevant to this role? What. do we know about their mechanisms of action in vitro as free radical scavengers?     

Do ectotherms partition thermal resources? We still do not know

Partitioning of the niche space is a mechanism used to explain the coexistence of similar species. Ectotherms have variable body temperatures and their body temperatures influence performance and, ultimately, fitness. Therefore, many ectotherms use behavioral thermoregulation to avoid reduced capacities associated with body temperatures far from the optimal temperature for performance. Several authors have proposed that thermal niche partitioning in response to interspecific competition is a mechanism that allows the coexistence of similar species of ectotherms. We reviewed studies on thermal resource partitioning to evaluate the evidence for this hypothesis. In almost all studies, there was insufficient evidence to conclude unequivocally that thermal resource partitioning allowed species coexistence. Future studies should include sites where species are sympatric and sites where they are allopatric to rule out alternative mechanisms that cause differences in thermal traits between coexisting species. There is evidence of conservatism in the evolution of most thermal traits across a wide range of taxa, but thermal performance curves and preferred temperatures do respond to strong selection under laboratory conditions. Thus, there is potential for selection to act on thermal traits in response to interspecific competition. Nevertheless, more stringent tests of the thermal resource partitioning hypothesis are required before we can assess whether it is widespread in communities of ectotherms in nature.     

Do We Feel the Same Empathy for Loved and Hated Peers?

Empathy allows us to understand and react to other people''s feelings and sensations; we can more accurately judge another person’s situation when we are aware of his/her emotions. Empathy for pain is a good working model of the behavioral and neural processes involved in empathy in general. Although the influence of perspective-taking processes (notably "Self" vs. "Other") on pain rating has been studied, the impact of the degree of familiarity with the person representing the “Other” perspective has not been previously addressed. In the present study, we asked participants to adopt four different perspectives: "Self", "Other-Most-Loved-Familiar", "Other-Most-Hated-Familiar" and "Other-Stranger". The results showed that higher pain ratings were attributed to the Other-Most-Loved-Familiar perspective than to the Self, Other-Stranger and Other-Most-Hated-Familiar perspectives. Moreover, participants were quicker to rate pain for the Other-Most-Loved-Familiar perspective and the Self-perspective than for the other two perspectives. These results for a perspective-taking task therefore more clearly define the role of familiarity in empathy for pain.     

What Do We Really Know about Cellulose Biosynthesis in Higher Plants?

Cellulose biosynthesis is one of the most important biochemical processes in plant biology. Despite the considerable progress made during the last decade, numerous fundamental questions related to this key process in plant development are outstanding. Numerous models have been proposed through the years to explain the detailed molecular events of cellulose biosynthesis. Almost all models integrate solid experimental data with hypotheses on several of the steps involved in the process. Speculative models are...     

Evaluating Tropical Biodiversity: Do We Need a More Refined Approach?

The exceptional biodiversity of tropical forests inspired the earliest ecologists such as H. W. Bates. Today we still strive to quantify and understand this diversity. Drawing on our own experience of Mamirauá reserve in Amazonas, which is located in an area that Bates explored, we argue that the emphasis of research in tropical ecosystems should shift away from species richness as an end in itself, and focus instead on other fundamental, but more tractable, questions that will increase our ecological understanding of these systems, support conservation management, and appeal to policy makers and society in general.