ALBERT

Beschreibung: Echolocation has evolved in different groups of animals, from bats and cetaceans to birds and humans, and enables localization and tracking of objects in a dynamic environment, where light levels may be very low or absent. Nature has shaped echolocation, an active sense that engages audiomotor feedback systems, which operates in diverse environments and situations. Echolocation production and perception vary across species, and signals are often adapted to the environment and task. In the last several decades, researchers have been studying the echolocation behavior of animals, both in the air and underwater, using different methodologies and perspectives. The result of these studies has led to rich knowledge on sound production mechanisms, directionality of the sound beam, signal design, echo reception and perception. Active control over echolocation signal production and the mechanisms for echo processing ultimately provide animals with an echoic scene or image of their surroundings. Sonar signal features directly influence the information available for the echolocating animal to perceive images of its environment. In many echolocating animals, the information processed through echoes elicits a reaction in motor systems, including adjustments in subsequent echolocation signals. We are interested in understanding how echolocating animals deal with different environments (e.g. clutter, light levels), tasks, distance to targets or objects, different prey types or other food sources, presence of conspecifics or certain predators, ambient and anthropogenic noise. In recent years, some researchers have presented new data on the origins of echolocation, which can provide a hint of its evolution. Theoreticians have addressed several issues that bear on echolocation systems, such as frequency or time resolution, target localization and beam-forming mechanisms. In this Research Topic we compiled recent work that elucidates how echolocation – from sound production, through echolocation signals to perception- has been shaped by nature functioning in different environments and situations. We strongly encouraged comparative approaches that would deepen our understanding of the processes comprising this active sense.

Beschreibung: The mucus surface layer of corals plays a number of integral roles in their overall health and fitness. This mucopolysaccharide coating serves as vehicle to capture food, a protective barrier against physical invasions and trauma, and serves as a medium to host a community of microorganisms distinct from the surrounding seawater. In healthy corals the associated microbial communities are known to provide antibiotics that contribute to the coral’s innate immunity and function metabolic activities such as biogeochemical cycling.Culture-dependent (Ducklow and Mitchell, 1979; Ritchie, 2006) and culture-independent methods (Rohwer, et al., 2001; Rohwer et al., 2002; Sekar et al., 2006; Hansson et al., 2009; Kellogg et al., 2009) have shown that coral mucus-associated microbial communities can change with changes in the environment and health condition of the coral. These changes may suggest that changes in the microbial associates not only reflect health status but also may assist corals in acclimating to changing environmental conditions. With the increasing availability of molecular biology tools, culture-independent methods are being used more frequently for evaluating the health of the animal host. Although culture-independent methods are able to provide more in-depth insights into the constituents of the coral surface mucus layer’s microbial community, their reliability and reproducibility rely on the initial sample collection maintaining sample integrity. In general, a sample of mucus is collected from a coral colony, either by sterile syringe or swab method (Woodley, et al., 2008), and immediately placed in a cryovial. In the case of a syringe sample, the mucus is decanted into the cryovial and the sealed tube is immediately flash-frozen in a liquid nitrogen vapor shipper (a.k.a., dry shipper). Swabs with mucus are placed in a cryovial, and the end of the swab is broken off before sealing and placing the vial in the dry shipper. The samples are then sent to a laboratory for analysis. After the initial collection and preservation of the sample, the duration of the sample voyage to a recipient laboratory is often another critical part of the sampling process, as unanticipated delays may exceed the length of time a dry shipper can remain cold, or mishandling of the shipper can cause it to exhaust prematurely. In remote areas, service by international shipping companies may be non-existent, which requires the use of an alternative preservation medium. Other methods for preserving environmental samples for microbial DNA analysis include drying on various matrices (DNA cards, swabs), or placing samples in liquid preservatives (e.g., chloroform/phenol/isoamyl alcohol, TRIzol reagent, ethanol). These methodologies eliminate the need for cold storage, however, they add expense and permitting requirements for hazardous liquid components, and the retrieval of intact microbial DNA often can be inconsistent (Dawson, et al., 1998; Rissanen et al., 2010).A method to preserve coral mucus samples without cold storage or use of hazardous solvents, while maintaining microbial DNA integrity, would be an invaluable tool for coral biologists, especially those in remote areas. Saline-saturated dimethylsulfoxide-ethylenediaminetetraacetic acid (20% DMSO-0.25M EDTA, pH 8.0), or SSDE, is a solution that has been reported to be a means of storing tissue of marine invertebrates at ambient temperatures without significant loss of nucleic acid integrity (Dawson et al., 1998, Concepcion et al., 2007). While this methodology would be a facile and inexpensive way to transport coral tissue samples, it is unclear whether the coral microbiota DNA would be adversely affected by this storage medium either by degradation of the DNA, or a bias in the DNA recovered during the extraction process created by variations in extraction efficiencies among the various community members. Tests to determine the efficacy of SSDE as an ambient temperature storage medium for coral mucus samples are presented here.