Concatenated Analysis Sheds Light on Early Metazoan Evolution and Fuels a Modern “Urmetazoon” Hypothesis

For more than a century, the origin of metazoan animals has been debated. One aspect of this debate has been centered on what the hypothetical “urmetazoon” bauplan might have been. The morphologically most simply organized metazoan animal, the placozoan Trichoplax adhaerens, resembles an intriguing model for one of several “urmetazoon” hypotheses: the placula hypothesis. Clear support for a basal position of Placozoa would aid in resolving several key issues of metazoan-specific inventions (including, for example, head–foot axis, symmetry, and coelom) and would determine a root for unraveling their evolution. Unfortunately, the phylogenetic relationships at the base of Metazoa have been controversial because of conflicting phylogenetic scenarios generated while addressing the question. Here, we analyze the sum of morphological evidence, the secondary structure of mitochondrial ribosomal genes, and molecular sequence data from mitochondrial and nuclear genes that amass over 9,400 phylogenetically informative characters from 24 to 73 taxa. Together with mitochondrial DNA genome structure and sequence analyses and Hox-like gene expression patterns, these data (1) provide evidence that Placozoa are basal relative to all other diploblast phyla and (2) spark a modernized “urmetazoon” hypothesis.     

Occurrence and distribution of organochlorine pesticide residue levels in water,sediment and aquatic weeds in the Nyando River catchment,Lake Victoria,Kenya

Samples of water, sediments and aquatic weeds were collected from 26 sites in the Nyando River catchment of the Lake Victoria basin in 2005–2006. The objective was to investigate levels of organochlorine pesticides that have either been banned or are restricted for use in Kenya. The pesticides investigated were lindane, aldrin, endosulfan, endrin, dieldrin, DDT, heptachlor and methoxychlor. These pesticides had previously found wide applications in public health and agriculture in Kenya for control of disease vectors and crop pests respectively. Results showed that mean concentrations were highest for methoxychlor (8.817 ± 0.020?µg l^?1) in water, sediments (92.893 ± 3.039 µg kg^?1), and weeds (39.641 ± 3.045?µg kg^?1), the weeds also tended to accumulate aldrin (15.519 ± 3.756?µg kg^?1). The results show that the pesticides are still in use and are detected in the catchment. Stringent management and public awareness measures are required to enforce the ban on the organochlorine pesticides in order to safeguard the environment and ecosystems of Lake Victoria.     

Testing the Effectiveness of an International Conservation Agreement: Marketplace Forensics and CITES Caviar Trade Regulation

Background

The international wildlife trade is a key threat to biodiversity. Temporal genetic marketplace monitoring can determine if wildlife trade regulation efforts such as the Convention on International Trade in Endangered Species (CITES) are succeeding. Protected under CITES effective 1997, sturgeons and paddlefishes, the producers of black caviar, are flagship CITES species.

Methodology/Principal Findings

We test whether CITES has limited the amount of fraudulent black caviar reaching the marketplace. Using mitochondrial DNA-based methods, we compare mislabeling in caviar and meat purchased in the New York City area pre and post CITES listing. Our recent sampling of this market reveals a decrease in mislabeled caviar (2006–2008; 10%; n = 90) compared to pre-CITES implementation (1995–1996; 19%; n = 95). Mislabeled caviar was found only in online purchase (n = 49 online/41 retail).

Conclusions/Significance

Stricter controls on importing and exporting as per CITES policies may be having a positive conservation effect by limiting the amount of fraudulent caviar reaching the marketplace. Sturgeons and paddlefishes remain a conservation priority, however, due to continued overfishing and habitat degradation. Other marine and aquatic species stand to benefit from the international trade regulation that can result from CITES listing.     

Modeling the eradication of invasive mammals using the sterile male technique

Large vertebrates, like the domestic goat (Capra hircus), have been transported all over the world and are an ecological disaster to numerous island and mainland ecosystems. Eradication measures for such species are generally centered on lethal methods of removing individuals, an increasingly difficult process as populations become smaller and individual animals become much more difficult to detect. In addition, methods of lethal removal are becoming less desirable in the public eye, prompting the necessity to explore alternatives. Here we investigate the use of the sterile males technique as an effective strategy in the eradication of large mammals. The results of our simulations suggest that the use of sterile males as a single strategy would only be an effective measure to eradicate relatively small (no more than 100 individuals) isolated feral vertebrate populations. However, our results indicate that the technique could be employed as a successful and potentially cost-effective end-point complement to lethal control and/or as a preventative measure against re-invasion.     

No Observed Effect of Landscape Fragmentation on Pathogen Infection Prevalence in Blacklegged Ticks (Ixodes scapularis) in the Northeastern United States

Pathogen prevalence within blacklegged ticks (Ixodes scapularis Say, 1821) tends to vary across sites and geographic regions, but the underlying causes of this variation are not well understood. Efforts to understand the ecology of Lyme disease have led to the proposition that sites with higher host diversity will result in lower disease risk due to an increase in the abundance of inefficient reservoir species relative to the abundance of species that are highly competent reservoirs. Although the Lyme disease transmission cycle is often cited as a model for this “dilution effect hypothesis”, little empirical evidence exists to support that claim. Here we tested the dilution effect hypothesis for two pathogens transmitted by the blacklegged tick along an urban-to-rural gradient in the northeastern United States using landscape fragmentation as a proxy for host biodiversity. Percent impervious surface and habitat fragment size around each site were determined to assess the effect of landscape fragmentation on nymphal blacklegged tick infection with Borrelia burgdorferi and Anaplasma phagocytophilum. Our results do not support the dilution effect hypothesis for either pathogen and are in agreement with the few studies to date that have tested this idea using either a landscape proxy or direct measures of host biodiversity.     

Trophic state and nutrient limitation in Lake Baringo,Kenya

The trophic state of Lake Baringo and factors that could be limiting the development of algal biomass in it were investigated during one wet/dry hydrological cycle in 2014–2015. Water samples were analysed for dissolved inorganic nutrients, including , and , total phosphorus and Chlorophyll a. Light attenuation was estimated using Secchi depth. The trophic state was determined using Carlson trophic state indices (CTSI). Deviations in CTSI, nutrient ratios and ambient nutrient concentrations were used to identify factors limiting phytoplankton growth. The mean values measured for Secchi depth, nitrate, total phosphorus and Chlorophyll a showed significant seasonal variation (p < 0.05). Based on the Carlson trophic state index, the results show that Lake Baringo is eutrophic. However, the lake is also experiencing phosphorus limitation and poor light penetration, because of high turbidity, which is more pronounced during the wet season.     

Reconciling apparent conflicts between mitochondrial and nuclear phylogenies in African elephants

Conservation strategies for African elephants would be advanced by resolution of conflicting claims that they comprise one, two, three or four taxonomic groups, and by development of genetic markers that establish more incisively the provenance of confiscated ivory. We addressed these related issues by genotyping 555 elephants from across Africa with microsatellite markers, developing a method to identify those loci most effective at geographic assignment of elephants (or their ivory), and conducting novel analyses of continent-wide datasets of mitochondrial DNA. Results showed that nuclear genetic diversity was partitioned into two clusters, corresponding to African forest elephants (99.5% Cluster-1) and African savanna elephants (99.4% Cluster-2). Hybrid individuals were rare. In a comparison of basal forest "F" and savanna "S" mtDNA clade distributions to nuclear DNA partitions, forest elephant nuclear genotypes occurred only in populations in which S clade mtDNA was absent, suggesting that nuclear partitioning corresponds to the presence or absence of S clade mtDNA. We reanalyzed African elephant mtDNA sequences from 81 locales spanning the continent and discovered that S clade mtDNA was completely absent among elephants at all 30 sampled tropical forest locales. The distribution of savanna nuclear DNA and S clade mtDNA corresponded closely to range boundaries traditionally ascribed to the savanna elephant species based on habitat and morphology. Further, a reanalysis of nuclear genetic assignment results suggested that West African elephants do not comprise a distinct third species. Finally, we show that some DNA markers will be more useful than others for determining the geographic origins of illegal ivory. These findings resolve the apparent incongruence between mtDNA and nuclear genetic patterns that has confounded the taxonomy of African elephants, affirm the limitations of using mtDNA patterns to infer elephant systematics or population structure, and strongly support the existence of two elephant species in Africa.     

Phylogenetic and evolutionary analyses of St. Louis encephalitis virus genomes

St. Louis encephalitis virus belongs to the Japanese encephalitis virus serocomplex of the genus Flavivirus, family Flaviviridae. Since the first known epidemic in 1933, the virus has been isolated from a variety of geographical, temporal, and host origins. We have sequenced 10,236 nucleotides of the open reading frame (93.6% of the full-length genome) of 23 of these strains, and have used the sequences to conduct phylogenetic analyses, in order to investigate the forces shaping the evolution of St. Louis encephalitis virus. Contrary to previous reports, we found little evidence for recombination in these isolates. Most of the amino acid sites in the SLEV polyprotein appeared to be under negative selection, with some sites evolving neutrally, and a small number under positive selection. The strongest signal for positive selection was evident in the N-linked glycosylation site of the envelope protein. Intra-strain sequence variability within strains was observed at this site, and analyses suggested that it is under selection in vitro. Furthermore, using heterochronous sequence data, we estimated the most recent expansion of St. Louis encephalitis virus in North America to have happened towards the end of the 19th century.     

澳门鸟类资源调查报告

1989～2009年在澳门山林和沿海滩涂湿地对鸟类进行了调查和记录,共记录鸟类297种,加上文献中记录的3种,整理出澳门鸟类名录共300种,隶属17目56科.其中非雀形目有30科160种,占澳门鸟类总种数的53.33%;雀形目有26科140种,占澳门鸟类种数46.67%.就数量来看,澳门鸟类中的优势种有9种,常见种44种,偶见种96种,稀有种则有151种.白腹海雕Haliaeetus leucogaster属于国家Ⅰ级重点保护野生鸟类.属于国家Ⅱ级重点保护的鸟类有33种.澳门鸟类属于<濒危野生动植物种国际贸易公约,2007>公约附录Ⅰ的有游隼Falco peregrinus peregrinus、小青脚鹬Tringa guttifer和小杓鹬Numenius minutus 3种,属于公约附录Ⅱ的有29种.勺嘴鹬Eurynorhynchus pygmeus被世界自然保护联盟(2009)列入极危(CR)鸟类,黑脸琵鹭Platalea minor和小青脚鹬被列入濒危(EN)鸟类.易危(VU)鸟类有4种,近危(NT)鸟类有5种.本文成果可为今后长期监测和保护澳门鸟类资源提供依据.