Paula Lado, Barbara Qurollo, Cathy Williams, Randall Junge, Hans Klompen. 2018. Ticks and Tick-borne Diseases. https://doi.org/10.1016/j.ttbdis.2018.05.003

Lemurs are primate species that are endemic to Madagascar. At present, about 90% of lemur species are endangered, and 5 species are among the 25 most endangered primates worldwide. Health status is a major factor impacting the viability of wild populations of many endangered species including lemurs. Given this context, we analyzed the microbiome of 24 specimens of Haemaphysalis lemuris, the most common tick parasitizing lemurs in their native habitats. Ticks were collected from 6 lemur species and microbiomes analyzed using next-generation sequencing. Our results show that the H. lemuris microbiome is highly diverse, including over 500 taxa, 267 of which were identified to genus level. Analysis of the microbiome also shows that there is a distinct “host” (lemur species) component when explaining the differences among and between microbial communities of H. lemuris. This “host” component seems to overwhelm any “locality” (geographic origin of the sample) component. In addition to the microbiome data, targeted PCR was used to test for the presence of three pathogens recently detected in the blood of wild lemurs: Borrelia sp., Candidatus Neoehrlichia sp., and Babesia sp. Overall, the presence of DNA of Rickettsia spp., Bartonella spp., Francisella spp., and a Babesia sp., in H. lemuris, is consistent with the hypothesis that these ectoparasites may act as vector for these pathogens. Further studies assessing vector competence are needed to confirm this hypothesis.

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Optimization of extraction methods for quantification of microcystin-LR and microcystin-RR in fish, vegetable, and soil matrices using UPLC–MS/MS

Manjunath Manubolu, Jiyoung Lee, Kenneth M. Riedl, Zi Xun Kua, Lindsay P. Collart, Stuart A.Ludsin. 2018. Harmful Algae (76) 47-57. https://doi.org/10.1016/j.hal.2018.04.009

Human-driven environmental change has increased the occurrence of harmful cyanobacteria blooms in aquatic ecosystems. Concomitantly, exposure to microcystin (MC), a cyanobacterial toxin that can accumulate in animals, edible plants, and agricultural soils, has become a growing public health concern. For accurate estimation of health risks and timely monitoring, availability of reliable detection methods is imperative. Nonetheless, quantitative analysis of MCs in many types of biological and environmental samples has proven challenging because matrix interferences can hinder sample preparation and extraction procedures, leading to poor MC recovery. Herein, controlled experiments were conducted to enhance the use of ultra-performance liquid-chromatography tandem-mass spectrometry (UPLC–MS/MS) to recover MC-LR and MC-RR at a range of concentrations in seafood (fish), vegetables (lettuce), and environmental (soil) matrices. Although these experiments offer insight into detailed technical aspects of the MC homogenization and extraction process (i.e., sonication duration and centrifugation speed during homogenization; elution solvent to use during the final extraction), they centered on identifying the best (1) solvent system to use during homogenization (2–3 tested per matrix) and (2) single-phase extraction (SPE) column type (3 tested) to use for the final extraction. The best procedure consisted of the following, regardless of sample type: centrifugation speed = 4200 × g; elution volume = 8 mL; elution solvent = 80% methanol; and SPE column type = hydrophilic–lipophilic balance (HLB), with carbon also being satisfactory for fish. For sonication, 2 min, 5 min, and 10 min were optimal for fish, lettuce, and soil matrices, respectively. Using the recommended HLB column, the solvent systems that led to the highest recovery of MCs were methanol:water:butanol for fish, methanol:water for lettuce, and EDTA-Na4P2O7 for soils. Given that the recommended procedures resulted in average MC-LR and MC-RR recoveries that ranged 93 to 98%, their adoption for the preparation of samples with complex matrices before UPLC–MS/MS analysis is encouraged.

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Increasing saugeye (S. vitreus × S. canadensis) production efficiency in a hatchery setting using assisted reproduction technologies

Bryan Blawut, Barbara Wolfe, Christa R. Moraes, Stuart A. Ludsin, Marco A. Coutinho da Silva. 2018. Aquaculture. (495) 21-26. https://doi.org/10.1016/j.aquaculture.2018.05.027

Assisted reproductive technologies (ART) are used to increase fertilization rates in a number of animal species. However, their use with sauger (Sander canadensis), the paternal contributor in the production of the recreationally and economically important saugeye (Sander vitreus × S. canadensis), is limited. State fishery management agencies are periodically unable to meet saugeye production goals due to the inability to collect sufficient numbers of sauger broodstock, as well as a lack of protocols for standardized sperm use during production. Therefore, the need exists to overcome sauger sperm limitation during the saugeye production season using ARTs. Toward this end, we investigated the effect of human chorionic gonadotropin (hCG) on sperm production, determined an efficient sperm-to-egg ratio for fertilization, and validated the use of a densimeter to measure sauger sperm cell concentration for precise sperm addition during fertilization. The effect of hCG on sperm production was evaluated by comparing pre- and post-treatment milt parameters between fish treated with either hCG or saline (control). Treating fish with hCG increased sperm volume relative to saline controls (hCG 0.64 ± 0.19 mL/kg; control: 0.31 ± 0.05 mL/kg). However, sperm cell concentration and total sperm production were unaffected. To determine an efficient sperm-to-egg ratio, fresh milt from several individuals was pooled and used to fertilize walleye eggs at three sperm-to-egg ratios (20,000, 50,000, and 100,000 sperm/egg). The range of sperm-to-egg ratios used in this study did not significantly affect fertilization rates (20,000: 82.67 ± 3.38%, 50,000: 91.33 ± 2.67% and 100,000: 88.67 ± 3.44%). Lastly, by using linear regression to compare densimeter and hemocytometer estimates in serially diluted sperm we were able to accurately estimate hemocytometer estimates (R2 = 0.96, p < 0.05). In conclusion, our study provides tools and standards that can be implemented by hatchery staff to increase saugeye production efficiency and lay the foundation for using ART for sauger and other fish species.

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Forest aging, disturbance and the carbon cycle

Peter S. Curtis  Christopher M. Gough. 2018. New Phytologist. 2018. https://doi.org/10.1111/nph.15227

Large areas of forestland in temperate North America, as well as in other parts of the world, are growing older and will soon transition into middle and then late successional stages exceeding 100 yr in age. These ecosystems have been important regional carbon sinks as they recovered from prior anthropogenic and natural disturbance, but their future sink strength, or annual rate of carbon storage, is in question. Ecosystem development theory predicts a steady decline in annual carbon storage as forests age, but newly available, direct measurements of forest net CO2 exchange challenge that prediction. In temperate deciduous forests, where moderate severity disturbance regimes now often prevail, there is little evidence for any marked decline in carbon storage rate during mid‐succession. Rather, an increase in physical and biological complexity under these disturbance regimes may drive increases in resource‐use efficiency and resource availability that help to maintain significant carbon storage in these forests well past the century mark. Conservation of aging deciduous forests may therefore sustain the terrestrial carbon sink, whilst providing other goods and services afforded by these biologically and structurally complex ecosystems.

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Global species delimitation and phylogeography of the circumtropical ‘sexy shrimp’ Thor amboinensis reveals a cryptic species complex and secondary contact in the Indo‐West Pacific

Benjamin M. Titus, Marymegan Daly, Natalie Hamilton, Michael L. Berumen, J. Antonio Baeza. 2018. Journal of Biogeography. https://doi.org/10.1111/jbi.13231

The “sexy shrimp” Thor amboinensis is currently considered a single circumtropical species. However, the tropical oceans are partitioned by hard and soft barriers to dispersal, providing ample opportunity for allopatric speciation. Herein, we test the null hypothesis that T. amboinensis is a single global species, reconstruct its global biogeographical history, and comment on population‐level patterns throughout the Tropical Western Atlantic.