Reproductive Consequences of Male Arrival Order in the Bark Beetle, Ips grandicollis

For group-living animals the choice of whether to join aggregations or initiate their own is influenced by potential benefits such as group protection and reduced energetic expenditure, as well as costs such as competition for food and mates. The bark beetle Ips grandicollis is an invasive pest species that colonises recently felled timber in Australian pine (Pinus spp.) plantations. Male beetles initiate colonies by burrowing under the bark of trees and emitting an aggregation pheromone which attracts conspecifics, including a harem of females with whom they mate. We predicted that males that initiated colonies, or who arrived early, would have larger harems than later arrivals (due to decreased competition for females). However, we found the opposite effect with early-arriving males actually associated with fewer females than later arriving males, although this may have resulted from some females leaving harems as they get older. We conclude that pioneering does not improve male likelihood of attracting females in Ips grandicollis, at least initially, but it may provide advantages for offspring when competing for food during development.     

Detecting Invasions of Marine Organisms: Kamptozoan Case Histories

Detecting marine invasions can be challenging, especially for lesser-known taxa, and requires (a) thorough field surveys of the region of interest for members of the taxon, (b) systematic analyses to identify all species found, (c) literature searches for the worldwide distribution of these species and for previous records of the taxon in this region, and (d) application of rigorous criteria to assess whether each species found is native or introduced. We carried out these steps in order to detect and document kamptozoan (entoproct) invasions on the American mid-Atlantic coast. We report on the occurrence of two colonial kamptozoans (Barentsia benedeni, Loxosomatoides laevis) in Chesapeake Bay (Maryland and Virginia, USA). On the American Atlantic coast, B. benedeni had previously only been reported from Massachusetts, although this species has a worldwide distribution in bays and harbors. The genus Loxosomatoides had not previously been reported from North America and L. laevis was known only from India. Since the genus Loxosomatoides was very poorly characterized, we briefly review all four of its species, which differ only slightly from each other. We have also synonymized L. japonicum with L. laevis. We did not find any of the kamptozoan species previously recorded in surveys of Chesapeake Bay and the American Atlantic coast. This is the first detailed consideration of anthropogenic influences on kamptozoan distributions, and we emphasize that most kamptozoan species are cryptogenic pending further investigation.     

天然产物防除海洋污损生物的研究进展

天然防污剂是当前海洋污损生物防除的研究热点,本文综述了天然防污剂的种类和来源,以及天然防污剂的防除机理,并着重叙述了天然防污涂料配制时应关注的问题。     

A Microtiter Plate Assay for Screening Antioxidant Activity in Extracts of Marine Organisms

A novel microtiter plate assay was developed to determine the total peroxyl radical-trapping activity of antioxidants extracted from marine organisms by measuring the inhibition rate of dye-substrate oxidation. We compared use of dihydrorhodamine-123, dihydrofluorescein, and dichlorodihydrofluorescein as reduced substrates for oxidation by peroxyl radicals generated from 2,2-azobis(2-amidinopropane) dihydrochloride. The oxidation products of these highly reactive substrates are intensely colored dyes that absorb maximally in the wavelength region, _max = 489 to 512 nm, and their concentrations were determined photometrically using a 96-well, microtiter plate reader. The microtiter plate method provides for concurrent multisample analysis with automated data storage, regression analyses, and calculation of oxidation inhibition rates. Dihydrorhodamine was selected as the preferred substrate for screening crude extracts, and typical assay results are presented. Novel lead antioxidants are selected from active extracts by chromatographic analysis with electrochemical detection.     

Global Patterns in Ecological Indicators of Marine Food Webs: A Modelling Approach

Background

Ecological attributes estimated from food web models have the potential to be indicators of good environmental status given their capabilities to describe redundancy, food web changes, and sensitivity to fishing. They can be used as a baseline to show how they might be modified in the future with human impacts such as climate change, acidification, eutrophication, or overfishing.

Methodology

In this study ecological network analysis indicators of 105 marine food web models were tested for variation with traits such as ecosystem type, latitude, ocean basin, depth, size, time period, and exploitation state, whilst also considering structural properties of the models such as number of linkages, number of living functional groups or total number of functional groups as covariate factors.

Principal findings

Eight indicators were robust to model construction: relative ascendency; relative overhead; redundancy; total systems throughput (TST); primary production/TST; consumption/TST; export/TST; and total biomass of the community. Large-scale differences were seen in the ecosystems of the Atlantic and Pacific Oceans, with the Western Atlantic being more complex with an increased ability to mitigate impacts, while the Eastern Atlantic showed lower internal complexity. In addition, the Eastern Pacific was less organised than the Eastern Atlantic although both of these systems had increased primary production as eastern boundary current systems. Differences by ecosystem type highlighted coral reefs as having the largest energy flow and total biomass per unit of surface, while lagoons, estuaries, and bays had lower transfer efficiencies and higher recycling. These differences prevailed over time, although some traits changed with fishing intensity. Keystone groups were mainly higher trophic level species with mostly top-down effects, while structural/dominant groups were mainly lower trophic level groups (benthic primary producers such as seagrass and macroalgae, and invertebrates). Keystone groups were prevalent in estuarine or small/shallow systems, and in systems with reduced fishing pressure. Changes to the abundance of key functional groups might have significant implications for the functioning of ecosystems and should be avoided through management.

Conclusion/significance

Our results provide additional understanding of patterns of structural and functional indicators in different ecosystems. Ecosystem traits such as type, size, depth, and location need to be accounted for when setting reference levels as these affect absolute values of ecological indicators. Therefore, establishing absolute reference values for ecosystem indicators may not be suitable to the ecosystem-based, precautionary approach. Reference levels for ecosystem indicators should be developed for individual ecosystems or ecosystems with the same typologies (similar location, ecosystem type, etc.) and not benchmarked against all other ecosystems.     

Polymethyleneamine Alkaloids of Animal Origin: I. Metabolites of Marine and Microbial Organisms

This review, issued in two parts, describes the information on the structure and biological activity of animal alkaloids derived from polymethyleneamines and produced by marine organisms, wasps, spiders, and microorganisms. Animal alkaloids are outstanding models for developing methods and drugs for the treatment of many human diseases. In the first part, we consider compounds produced by marine and microbial organisms. Some promising synthetic analogues of these alkaloids are used in developing modern preparations for the chelate therapy of excessive blood iron content and antituberculosis, antiproliferative, and immunosuppressive drugs.     

A Fast Electrophoretic Isoenzyme Technique for the Identification of Invasive and Non-Invasive Entamoeba histolytica and E. hitolytica-like Organisms

Cellulose acetate electrophoresis (CAE) was used to separate glucosephosphate isomerase, hexokinase, malic enzyme, and phosphoglucomutase extracted from invasive and non-invasive Entamoeba histolytica and E. histolytica -like organisms. Each of these morphologically similar organisms possessed a unique CAE isoenzyme profile that can be used as an aid in their identification. The CAE technique used to obtain these isoenzyme profiles is rapid, simple, and economical, and it requires neither specialized training nor claborate equipment.     

Test for Standard Form of the Species Structure in Taxocenes of Marine Organisms

The statistical test that allows us to assign a community consisting of a competitive species to one of three groups differing in the level of species diversity is substantiated. This test is derived from the Motomura–Whittaker model, which describes the normal relationship of species abundance in their ordered list. The amphipod community is used as an example.     

International Trade Modelling Using Open Flow Networks: A Flow-Distance Based Analysis

This paper models and analyzes international trade flows using open flow networks (OFNs) with the approaches of flow distances, which provide a novel perspective and effective tools for the study of international trade. We discuss the establishment of OFNs of international trade from two coupled viewpoints: the viewpoint of trading commodity flow and that of money flow. Based on the novel model with flow distance approaches, meaningful insights are gained. First, by introducing the concepts of trade trophic levels and niches, countries’ roles and positions in the global supply chains (or value-added chains) can be evaluated quantitatively. We find that the distributions of trading “trophic levels” have the similar clustering pattern for different types of commodities, and summarize some regularities between money flow and commodity flow viewpoints. Second, we find that active and competitive countries trade a wide spectrum of products, while inactive and underdeveloped countries trade a limited variety of products. Besides, some abnormal countries import many types of goods, which the vast majority of countries do not need to import. Third, harmonic node centrality is proposed and we find the phenomenon of centrality stratification. All the results illustrate the usefulness of the model of OFNs with its network approaches for investigating international trade flows.     

The Role of Pre-Existing Disturbances in the Effect of Marine Reserves on Coastal Ecosystems: A Modelling Approach

We have used an end-to-end ecosystem model to explore responses over 30 years to coastal no-take reserves covering up to 6% of the fifty thousand square kilometres of continental shelf and slope off the coast of New South Wales (Australia). The model is based on the Atlantis framework, which includes a deterministic, spatially resolved three-dimensional biophysical model that tracks nutrient flows through key biological groups, as well as extraction by a range of fisheries. The model results support previous empirical studies in finding clear benefits of reserves to top predators such as sharks and rays throughout the region, while also showing how many of their major prey groups (including commercial species) experienced significant declines. It was found that the net impact of marine reserves was dependent on the pre-existing levels of disturbance (i.e. fishing pressure), and to a lesser extent on the size of the marine reserves. The high fishing scenario resulted in a strongly perturbed system, where the introduction of marine reserves had clear and mostly direct effects on biomass and functional biodiversity. However, under the lower fishing pressure scenario, the introduction of marine reserves caused both direct positive effects, mainly on shark groups, and indirect negative effects through trophic cascades. Our study illustrates the need to carefully align the design and implementation of marine reserves with policy and management objectives. Trade-offs may exist not only between fisheries and conservation objectives, but also among conservation objectives.     

Modelling the Stoichiometric Regulation of C-Rich Toxins in Marine Dinoflagellates

Toxin production in marine microalgae was previously shown to be tightly coupled with cellular stoichiometry. The highest values of cellular toxin are in fact mainly associated with a high carbon to nutrient cellular ratio. In particular, the cellular accumulation of C-rich toxins (i.e., with C:N > 6.6) can be stimulated by both N and P deficiency. Dinoflagellates are the main producers of C-rich toxins and may represent a serious threat for human health and the marine ecosystem. As such, the development of a numerical model able to predict how toxin production is stimulated by nutrient supply/deficiency is of primary utility for both scientific and management purposes. In this work we have developed a mechanistic model describing the stoichiometric regulation of C-rich toxins in marine dinoflagellates. To this purpose, a new formulation describing toxin production and fate was embedded in the European Regional Seas Ecosystem Model (ERSEM), here simplified to describe a monospecific batch culture. Toxin production was assumed to be composed by two distinct additive terms; the first is a constant fraction of algal production and is assumed to take place at any physiological conditions. The second term is assumed to be dependent on algal biomass and to be stimulated by internal nutrient deficiency. By using these assumptions, the model reproduced the concentrations and temporal evolution of toxins observed in cultures of Ostreopsis cf. ovata, a benthic/epiphytic dinoflagellate producing C-rich toxins named ovatoxins. The analysis of simulations and their comparison with experimental data provided a conceptual model linking toxin production and nutritional status in this species. The model was also qualitatively validated by using independent literature data, and the results indicate that our formulation can be also used to simulate toxin dynamics in other dinoflagellates. Our model represents an important step towards the simulation and prediction of marine algal toxicity.     

Underwater Adhesive of Marine Organisms as the Vital Link Between Biological Science and Material Science

Marine sessile organisms naturally attach themselves to diverse materials in water by a technique that has so far remained unreproducible. Recent studies on the holdfast of marine sessile organisms have revealed natural concepts that are currently beyond our understanding with respect to the molecular design and macroscopic range. The combination of valuable and practical natural design of biotic adhesives as biomolecular materials, together with continuing efforts towards mimetic design, hold the promise of revolution for future materials. This review focuses on recent advances in the study of barnacle underwater cement, a protein complex whose constituents and the properties of individual components are being uncovered. A comparison is made with the model systems used by the mussel and tubeworm.     

A Cytogenetic Study of the Leaf Beetle Genus Cyrtonus (Coleoptera, Chrysomelidae)

The chromosomes of ten species of Cyrtonus and the genome sizes of six are surveyed. Among the total of 15 chromosomally studied species, 11 have 2n=28 chromosomes and a 13+Xy_p male meioformula, three have 2n=40 and 19+Xy_p and one 2n=46 and 22+Xy_p. All but one species with 28 chromosomes show only metacentric or submetacentric chromosomes, whereas the species with 40 and 46 chromosomes display some telocentrics or subtelocentrics, that are probably derived from the former by centric fissions. However, since the number of major chromosome arms is strikingly higher in these latter species (NF=70 and 78) than in the 28-chromosome species (mostly NF=56), other chromosomal rearrangements such as pericentric inversions or heterochromatin accretions could also be involved. The genome sizes display a narrow range, from 1C=0.6–1.22pg, and they are not significantly correlated with the chromosome numbers. Some possible factors implied in the rough chromosomal evolution of Cyrtonus are discussed in relation to a few other genera of the subfamily Chrysomelinae.     

Risk Factors for Invasive Cryptococcus neoformans Diseases: A Case-Control Study

Background

Cryptococcus neoformans is a ubiquitous environmental fungus that can cause life-threatening meningitis and fungemia, often in the presence of acquired immunodeficiency syndrome (AIDS), liver cirrhosis, diabetes mellitus, or other medical conditions. To distinguish risk factors from comorbidities, we performed a hospital-based, density-sampled, matched case-control study.

Methods

All new-onset cryptococcal meningitis cases and cryptococcemia cases at a university hospital in Taiwan from 2002–2010 were retrospectively identified from the computerized inpatient registry and were included in this study. Controls were selected from those hospitalized patients not experiencing cryptococcal meningitis or cryptococcemia. Controls and cases were matched by admission date, age, and gender. Conditional logistic regression was used to analyze the risk factors.

Results

A total of 101 patients with cryptococcal meningitis (266 controls) and 47 patients with cryptococcemia (188 controls), of whom 32 patients had both cryptococcal meningitis and cryptococcemia, were included in this study. Multivariate regression analysis showed that AIDS (adjusted odds ratio [aOR] = 181.4; p < 0.001), decompensated liver cirrhosis (aOR = 8.5; p = 0.008), and cell-mediated immunity (CMI)-suppressive regimens without calcineurin inhibitors (CAs) (aOR = 15.9; p < 0.001) were independent risk factors for cryptococcal meningitis. Moreover, AIDS (aOR = 216.3, p < 0.001), decompensated liver cirrhosis (aOR = 23.8; p < 0.001), CMI-suppressive regimens without CAs (aOR = 7.3; p = 0.034), and autoimmune diseases (aOR = 9.3; p = 0.038) were independent risk factors for developing cryptococcemia. On the other hand, diabetes mellitus and other medical conditions were not found to be risk factors for cryptococcal meningitis or cryptococcemia.

Conclusions

The findings confirm AIDS, decompensated liver cirrhosis, CMI-suppressive regimens without CAs, and autoimmune diseases are risk factors for invasive C. neoformans diseases.