The calls of Vietnamese bats: a major step toward the acoustic characterization of Asian bats.

Southeast Asia includes several global biodiversity hotspots and bats account for nearly one-third of mammal species currently known in the region. While acoustic methods have become widespread in bat research, basic information is often lacking on the echolocation calls produced by Asian bat species. Since such information can aid a wide variety of research and conservation initiatives, descriptions of the calls emitted by Asian bats are fundamental. The aim of our study was to provide a standardized analysis and description of the Vietnamese bat echolocation calls. We analyzed call recordings of 87 species arranged in eight families. This constitutes 74% of the echolocating bats presently known in Vietnam and includes the first call descriptions for five taxa. Our use of an open-source software and the deposition of recordings in the ChiroVox repository will facilitate comparative studies in Asia and the information we provide represents one of the most comprehensive bioacoustic databases for Asian bats to date.

A modified CTAB method for the extraction of high-quality RNA from mono-and dicotyledonous plants rich in secondary metabolites.

BACKGROUND: High-quality RNA extraction from woody plants is difficult because of the presence of polysaccharides and polyphenolics that bind or co-precipitate with the RNA. The CTAB (cetyl trimethylammonium bromide) based method is widely used for the isolation of nucleic acids from polysaccharide-rich plants. Despite the widespread use of the CTAB method, it is necessary to adapt it to particular plant species, tissues and organs. Here we described a simple and generalized method for RNA isolation from mature leaf tissues of several economically important woody (17) and herbaceous plants (2) rich in secondary metabolites. High yields were achieved from small amount (up to 50 mg) of plant material. Two main modifications were applied to the basic protocol: an increase in ß-mercaptoethanol concentration (to 10%v/v) and the use of an effective DNase treatment. As opposed to similar studies, we tried to describe a more detailed protocol for isolating RNA, including the exact quantity and concentration of the reagents were used. RESULTS: Our modified CTAB method is proved to be efficient in extracting the total RNA from a broad range of woody and herbaceous species. The RNA yield was ranged from 2.37 to 91.33 µg/µl. The A260:A280 and A260:A230 absorbance ratios were measured from 1.77 to 2.13 and from 1.81 to 2.22. The RIN value (RNA Integrity Number) of the samples fell between 7.1 and 8.1, which indicated that a small degree of RNA degradation occurred during extraction. The presence of a single peak in the melt curve analyses and low standard errors of the Ct values of replicated measurements indicated the specificity of the primers to bind to the cDNA. CONCLUSIONS: Our RNA isolation method, with fine-tuned and detailed instructions, can produce high quality RNA from a small amount of starting plant material that is suitable for use in downstream transcriptional analyses. The use of an increased concentration of the reducing agent ß-mercaptoethanol in the extraction buffer, as well as the application of DNaseI-treatment resulted in a method suitable for a wide range of plants without the need of further optimalization, especially in Rhus typhina (Staghorn sumac), for which molecular-genetic studies have not yet been sufficiently explored.

ChiroVox: a public library of bat calls.

Recordings of bat echolocation and social calls are used for many research purposes from ecological studies to taxonomy. Effective use of these relies on identification of species from the recordings, but comparative recordings or detailed call descriptions to support identification are often lacking for areas with high biodiversity. The ChiroVox website (https://www.chirovox.org) was created to facilitate the sharing of bat sound recordings together with their metadata, including biodiversity data and recording circumstances. To date, more than 30 researchers have contributed over 3,900 recordings of nearly 200 species, making ChiroVox the largest open-access bat call library currently available. Each recording has a unique identifier that can be cited in publications; hence the acoustic analyses are repeatable. Most of the recordings available through the website are from bats whose species identities are confirmed, so they can be used to determine species in recordings where the bats were not captured or could not be identified. We hope that with the help of the bat researcher community, the website will grow rapidly and will serve as a solid source for bat acoustic research and monitoring.