107 research outputs found
Costs and benefits of an extended phenotype: Chambers made by Manduca sexta larvae
Extended phenotypes can serve interesting physiological functions and their externality provides ready opportunity to manipulate and examine their functions and costs. One such set of extended phenotypes are below-ground pupation chambers made by a wide range of insects and whose function is unknown and costs unquantified. We use a series of lab and field experiments to examine the cost and benefit of chambers made by the hawkmoth, Manduca sexta (Sphingidae), whose larvae lose up to 60% of their body mass during chamber construction. Our study shows that these chambers provide critically important free space in which individuals transition from larvae to pupae and from pupae to adults, and that the cost of making chambers, as measured by pre-pupal mass loss, increases rapidly in dry soils. However, we found no evidence that chambers provide any benefit during metamorphosis, nor do they affect the microclimate or prevent predation by soil pathogens or predators. These results are broadly applicable to holometabolous insects and provide perhaps the most basal explanation for the evolution of complex chamber building behavior
Evidence for Irruptive Fluctuation in Axis Deer of Hawai‘i
Axis deer on the Hawaiian Islands of Maui, Lāna‘i, and Moloka‘i simultaneously experienced one of the most dramatic population crashes on record in 2020-2021, which coincided with extended drought conditions and prompted an emergency declaration for these islands. This phenomenon has been anecdotally documented during previous drought events in 2011-2012, but never formally studied. Newspaper articles document abundant deer becoming a nuisance to agriculture and natural resources, and then experiencing high mortality during droughts. This phenomenon fits Caughley’s (1970) operational definition of eruptive (sic) fluctuation “…as an increase in numbers over at least two generations, followed by a marked decline.” We examined available deer population and rainfall records over the time period of interest. Deer may have increased rapidly during favorable years with high survival and recruitment. During moderate drought, young of the year may experience high mortality, with little recruitment to populations. During severe drought, adults may experience noticeably high mortality. When populations are suppressed by large numbers of removals, fluctuations in mortality may be modulated. Abandonment of large-scale intensive agriculture in recent decades may complicate interpretation but understanding these population processes may lead to better management strategies for axis deer in Hawai‘i
TCR hypervariable regions expressed by T cells that respond to effective tumor vaccines
A major goal of immunotherapy for cancer is the activation of T cell responses against tumor-associated antigens (TAAs). One important strategy for improving antitumor immunity is vaccination with peptide variants of TAAs. Understanding the mechanisms underlying the expansion of T cells that respond to the native tumor antigen is an important step in developing effective peptide-variant vaccines. Using an immunogenic mouse colon cancer model, we compare the binding properties and the TCR genes expressed by T cells elicited by peptide variants that elicit variable antitumor immunity directly ex vivo. The steady-state affinity of the natural tumor antigen for the T cells responding to effective peptide vaccines was higher relative to ineffective peptides, consistent with their improved function. Ex vivo analysis showed that T cells responding to the effective peptides expressed a CDR3β motif, which was also shared by T cells responding to the natural antigen and not those responding to the less effective peptide vaccines. Importantly, these data demonstrate that peptide vaccines can expand T cells that naturally respond to tumor antigens, resulting in more effective antitumor immunity. Future immunotherapies may require similar stringent analysis of the responding T cells to select optimal peptides as vaccine candidates. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00262-012-1217-5) contains supplementary material, which is available to authorized users
Ecological Associations of Nonnative Ungulates on the Hawaiian Island of Lāna‘i
Abstract: Sustained-yield hunting of introduced ungulates in the Hawaiian Islands often conflicts with the conservation of native species, but there is little reliable data to guide effective management. European mouflon sheep (Ovis musimon; mouflon) and axis deer (Axis axis; deer) were introduced on the island of Lāna‘i to provide additional hunting opportunities. Managers will require better information regarding the ecological associations of introduced ungulate species, relative to the habitats occupied, to resolve longstanding conflicts between native species conservation and sustained-yield hunting on islands. To address this information need, we modeled sheep and deer ecological associations, habitat-use, and suitability using data obtained from an intensive aerial survey completed in 2013 and temporally matching environmental data. In habitat suitability models evaluated by Receiver Operating Characteristic (ROC) metrics, predictor importance in a generalized linear model (GLM) of deer decreased in the following order: afternoon cloud cover, topographic slope, mean annual precipitation (MAP), elevation, normalized difference vegetation index (NDVI), and bare soil index. In a random GLM model of mouflon, predictor importance decreased in the following order: afternoon cloud cover, deer habitat suitability, NDVI, bare soil index, topographic slope, elevation, and MAP. Mouflon were restricted to lower elevation arid slopes, whereas deer were more broadly distributed throughout upland environments of the island. The presence of deer was also an important predictor for mouflon distribution, although mouflon was not an important predictor of deer, suggesting asymmetrical competition. Removal of the more abundant deer population may lead to an increase in abundance and distribution of mouflon without containment. This work represents the first habitat suitability analysis for all nonnative ungulates on any entire Hawaiian island. Our results are applicable to other islands where conflicts may arise with introduced ungulates, sustained-yield hunting, and native species conservation
Development of tree snail protection enclosures: From design to implementation
Reports were scanned in black and white at a resolution of 600 dots per inch and were converted to text using Adobe Paper Capture Plug-in.The Hawaiian land snails in the endangered, endemic genus Achatinella have experienced major declines in population and distribution over the last 100 years. Threats to Achatinella today include invasive, non‐native predators (Euglandina rosea, Rattus rattus and Trioceros jacksonii), habitat degradation due to human disturbance and possibly climate change, and historically, collection by humans. The O‘ahu Army Natural Resources Program (OANRP) is required to stabilize select remaining populations of A. mustelina. Stabilization goals are to maintain 300 mature snails at eight managed sites and control threats within sites. This report describes OANRP efforts to combat invasive predators by means of predator‐free and ‐proof snail enclosures. A couple of prior attempts at excluding predatory snails were marginally successful but the identification of additional predators required substantial additional barriers. The design and construction of the enclosure at Pu‘u Hapapa is used as a case study. This report includes detailed information on the physical development of predator‐proof barriers, construction and costs. Additional needs for monitoring and maintenance, predator removal, Achatinella reintroduction, Achatinella population monitoring, and habitat improvement were also developed.Funded by: U.S. Army via U.S. Army Corps of Engineers Cooperative Agreement W9126G-10-2-001
TRP drop, TRP drop: a steady patter of anti-schistosomal target illumination
Infections caused by parasitic flatworms impart a significant disease burden. This is well exemplified by the neglected tropical disease schistosomiasis, which afflicts millions of people worldwide. The anti-schistosomal activity of various chemotypes has been known for decades, but the parasite targets of many of these remain undefined. Until recently, this included the current clinical therapy, praziquantel (PZQ). However, the tempo of target discovery has recently gathered pace, with discoveries of schistosome targets for praziquantel (PZQ) and the anthelmintic benzodiazepine, meclonazepam (MCLZ). This steady patter of target illumination has also revealed a pattern in that both PZQ and MCLZ target members of the same ion channel subgroup—transient receptor potential ion channels of the melastatin family (TRPM channels). PZQ activates one member of this family (TRPMPZQ) and MCLZ activates a different channel (TRPMMCLZ). Here, similarities and differences between these two new targets are discussed. These data highlight the need for further study of TRPM channels in parasitic flatworms given their vulnerability to chemotherapeutic attack
A Comprehensive Economic Stimulus for our Failing Economy
This paper presents a comprehensive plan to fix the ailing American economy, through a five-step approach. First, the Federal Reserve must continue to broaden the scope of monetary policy, by purchasing and selling long-term securities. Manipulating expectations through FOMC statements is another tool at the Federal Reserve’s disposal. Secondly, the government must enact fiscal stimulus to stabilize the economy in the short and medium runs, through investment in infrastructure projects, green technology, fusion technology, and science education. Additionally, the new fiscal policy must tackle the mortgage meltdown, which is weighing down the entire economy. Third, the regulatory system must be changed to reduce the likelihood of another financial collapse, starting with the nationalization of the ratings agencies. Ratings should be updated faster, with a numeric grading system rather than the pre-existing letter grades. Fourth, our globalized economy insures that a coordinated globalized response is necessary to recover. Global cooperation to reduce inflation and avoid protectionist policies is vital. Finally, the American bailout policy must be made clear, only giving bailouts to companies that are sound but financially strapped and those that are too big to fail
The Anthelmintic Activity of Praziquantel Analogs Correlates with Structure-Activity Relationships at TRPMPZQ Orthologs.
The anthelmintic drug praziquantel remains a key clinical therapy for treating various diseases caused by parasitic flatworms. The parasite target of praziquantel has remained undefined despite longstanding usage in the clinic, although a candidate ion channel target, named TRPMPZQ, has recently been identified. Intriguingly, certain praziquantel derivatives show different activities against different parasites: for example, some praziquantel analogs are considerably more active against cestodes than against schistosomes. Here we interrogate whether the different activities of praziquantel analogs against different parasites are also reflected by unique structure-activity relationships at the TRPMPZQ channels found in these different organisms. To do this, several praziquantel analogs were synthesized and functionally profiled against schistosome and cestode TRPMPZQ channels. Data demonstrate that structure-activity relationships are closely mirrored between parasites and their TRPMPZQ orthologs, providing further support for TRPMPZQ as the therapeutically relevant target of praziquantel
Revisiting the Hetero-Fertilization Phenomenon in Maize
Development of a seed DNA-based genotyping system for marker-assisted selection (MAS) has provided a novel opportunity for understanding aberrant reproductive phenomena such as hetero-fertilization (HF) by observing the mismatch of endosperm and leaf genotypes in monocot species. In contrast to conventional approaches using specific morphological markers, this approach can be used for any population derived from diverse parental genotypes. A large-scale experiment was implemented using seven F2 populations and four three-way cross populations, each with 534 to 1024 individuals. The frequency of HF within these populations ranged from 0.14% to 3.12%, with an average of 1.46%. The highest frequency of HF in both types of population was contributed by the pollen gametes. Using three-way crosses allowed, for the first time, detection of the HF contributed by maternal gametes, albeit at very low frequency (0.14%–0.65%). Four HF events identified from each of two F2 populations were tested and confirmed using 1032 single nucleotide polymorphic markers. This analysis indicated that only 50% of polymorphic markers can detect a known HF event, and thus the real HF frequency can be inferred by doubling the estimate obtained from using only one polymorphic marker. As expected, 99% of the HF events can be detected by using seven independent markers in combination. Although seed DNA-based analysis may wrongly predict plant genotypes due to the mismatch of endosperm and leaf DNA caused by HF, the relatively low HF frequencies revealed with diverse germplasm in this study indicates that the effect on the accuracy of MAS is limited. In addition, comparative endosperm and leaf DNA analysis of specific genetic stocks could be useful for revealing the relationships among various aberrant fertilization phenomena including haploidy and apomixis
The Aspergillus Genome Database, a curated comparative genomics resource for gene, protein and sequence information for the Aspergillus research community
The Aspergillus Genome Database (AspGD) is an online genomics resource for researchers studying the genetics and molecular biology of the Aspergilli. AspGD combines high-quality manual curation of the experimental scientific literature examining the genetics and molecular biology of Aspergilli, cutting-edge comparative genomics approaches to iteratively refine and improve structural gene annotations across multiple Aspergillus species, and web-based research tools for accessing and exploring the data. All of these data are freely available at http://www.aspgd.org. We welcome feedback from users and the research community at [email protected]
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