Neuromodulators and transmitters in respiratory control

The respiratory control system is influenced by classical neurotransmitters and by neuromodulators. The neuromodulators are neuroactive substances that can be secreted at a distance from their receptors and must diffuse to their site of action. Their function can be nonsynaptic and long lasting, and their effect can be direct or indirect via other neuroactive substances. In the central nervous system, a variable degree of mismatch exists between sites of neuromodulator secretion and reception. The assignment of a natural role for a neuromodulator in respiratory control is strengthened by evidence from a variety of experimental approaches, including localization of receptor sites in respiratory-related areas and evidence for natural binding of neuromodulators to these receptors, neurophysiological and respiratory responses to the neuromodulators and their antagonists, and, finally, modulation of specific respiratory responses by neuromodulator antagonists to document the role of the endogenous modulator in eliciting the original response. Neuromodulators that are considered seriously as natural participants in respiratory control include dopamine in peripheral chemoreception and adenosine, endorphins (including enkephalins), serotonin, and substance P in central respiratory regulation.     

Closing the gap between science and management of cold-water refuges in rivers and streams

Human activities and climate change threaten coldwater organisms in freshwater ecosystems by causing rivers and streams to warm, increasing the intensity and frequency of warm temperature events, and reducing thermal heterogeneity. Cold-water refuges are discrete patches of relatively cool water that are used by coldwater organisms for thermal relief and short-term survival. Globally, cohesive management approaches are needed that consider interlinked physical, biological, and social factors of cold-water refuges. We review current understanding of cold-water refuges, identify gaps between science and management, and evaluate policies aimed at protecting thermally sensitive species. Existing policies include designating cold-water habitats, restricting fishing during warm periods, and implementing threshold temperature standards or guidelines. However, these policies are rare and uncoordinated across spatial scales and often do not consider input from Indigenous peoples. We propose that cold-water refuges be managed as distinct operational landscape units, which provide a social and ecological context that is relevant at the watershed scale. These operational landscape units provide the foundation for an integrated framework that links science and management by (1) mapping and characterizing cold-water refuges to prioritize management and conservation actions, (2) leveraging existing and new policies, (3) improving coordination across jurisdictions, and (4) implementing adaptive management practices across scales. Our findings show that while there are many opportunities for scientific advancement, the current state of the sciences is sufficient to inform policy and management. Our proposed framework provides a path forward for managing and protecting cold-water refuges using existing and new policies to protect coldwater organisms in the face of global change.     

A rapid method for quantitation of immunofluorescence on human lymphoblastoid cell suspensions.

A quantitative fluoroimmunoassay for antibodies to, and surface antigens of, human lymphoblastoid cells (IM-1) with photon-counting spectrofluorometry is described. IM-1 cell suspensions were reacted with rabbit antiserum to human spleen vesicular membranes, were washed, and then were reacted with an excess amount of fluorochrome-conjugated (fluorescein or rhodamine) goat anti-rabbit immunoglobulin G (IgG). Under appropriate conditions, antibodies to IM-1 cells could be detected with experimental/control fluorescence ratios ranging between 5 and 40. Moreover, detectable levels of antibody-saturated cells approached 5 × 10³ cells per milliliter or a total of 1.7 × 10³ cells per assay. Inhibition of the fluoroimmunoassay was performed with either viable IM-1 cells or IM-1 vesicular membrane preparations and demonstrated a dose-dependent antigen inhibition. Fluorescence of sensitized cells reactive with either fluorescein- or rhodamine-labeled antiglobulins could be quantitatively distinguished in dual-labeled preparations.