Search

Sirtuins are a class of NAD+-dependent deacylases, with known regulatory roles in energy metabolism and cellular stress responses in vertebrates. Previous work using marine mussels have suggested a similar role in invertebrates, providing a potential mechanism linking food availability and thermal sensitivity in Mytilids. Sirtuin inhibitors affect mussels' recovery from environmental stressors, including acute heat shock and well-fed mussels exposed to sirtuin inhibitors and/or acute heat shock respond differently than poorly fed mussels, at the protein and whole-organism levels. While this implies a relationship between sirtuins, food availability, and temperature, the direct effects of sirtuin inhibitors (nicotinamide and suramin) on sirtuin activity or their putative effectors have not been explicitly tested. In this study, adult Mytilus californianus were acclimated to a low or high food availability and exposed to one of the following treatments: control, acute heat shock, sirtuin inhibitors, or acute heat shock and sirtuin inhibitors. Mussels increased sirtuin activity during early recovery (5 h) from sirtuin inhibition and acute heat shock, but only if acclimated to a high food availability. Redox balance was also impacted in mussels acclimated to high food availability and exposed to sirtuin inhibitors, signifying interactions between ration, acute heat shock, and sirtuin inhibitors. Additionally, we found a correlation between sirtuin and superoxide dismutase activities, suggesting a potential regulatory role of oxidative stress by sirtuins. Following prolonged recovery (17 h), we found increased sirtuin activity in mussels acclimated to low food availability, indicating that endogenous sirtuin activity may be related to food availability in mussels. [Display omitted] • Sirtuin activity is increased in mussels acclimated to low food availability. • Sirtuins increase after heat shock and inhibition, but only in well fed mussels. • Superoxide dismutase activity has a positive correlation with sirtuin activity. • Well-fed mussels respond differently to heat shock than mussels with low food availability. [ABSTRACT FROM AUTHOR]

The Giant Gartersnake (Thamnophis gigas) is a low density visually evasive species with a low detection probability based on standard field survey methods (e.g., traps, visual census). Habitat loss has resulted in extirpations or serious declines for T. gigas populations throughout the southern two thirds of its historic range. Uncertainty regarding its current distribution and occupancy present management challenges for the species. Enhancing survey sensitivity through development of environmental DNA sampling (eDNA) methods would improve compliance monitoring under the Endangered Species Act, recovery planning for T. gigas, and evaluation of California’s Central Valley tule marsh habitat on which this species depends. To address these needs, we designed and validated diagnostic quantitative Polymerase Chain Reaction (qPCR) assays for identifying portions of the Cytochrome B (CytB) and the Nicotinamide adenine dinucleotide (NADH) dehydrogenase subunit 4 (ND4) genes of the T. gigas mitochondrial genome. The designed ND4 qPCR assay was not specific to T. gigas DNA and amplified DNA from a closely related and spatially co-occurring Thamnophis species (T.s. fitchi). The CytB T. gigas qPCR assay proved specific to a species level with a sensitivity that reliably detected T. gigas DNA at a concentration of 2.0x10-5 ng μL-1. To assess detection range, coordinated field sampling was conducted at aquatic sites with an observed and documented population of T. gigas. The T. gigas qPCR assay reliably detected DNA from samples taken 300m downstream from the known source. We then used environmental eDNA sampling and qPCR analysis to augment unsuccessful trap surveys in the southern range of T. gigas and detected DNA in 28 of the 52 locations sampled, confirming that T. gigas was still present at some sites where physical trapping failed to identify presence. QPCR-based DNA detection coupled with eDNA sampling methods provides an effective means to obtain critical population metrics from this otherwise cryptic, federally protected and hard to study organism, offering great promise for elucidating patterns of occupancy with greater efficiency and at far less cost than trapping methods, particularly where detection probabilities are low. [ABSTRACT FROM AUTHOR]

Presents abstracts of studies on reactive oxygen species, presented at the Experimental Biology/International Union of Physiological Sciences 2005 congress held in San Diego, California. "NADPH Oxidase Is Essential for Angiotensin II-induced Production of Reactive Oxygen Species in Second-Order Dorsomedial NTS Neurons," by Gang Wang, Ping Zhou et al.; "Angiotensin II Evoked Increases in Reactive Oxygen Species in Subfornical Organ Neurons in the Living Brain Slice," by Yuanzi Zhao, Meredith Hay et al.; "Simvastatin Therapy Normalizes Sympathetic Neural Control in Experimental Heart Failure: The Roles of AT1 Receptors and NAD(P)H Oxidase," by Lie Gao, Wei Wang et al.

Presents abstracts of studies on vascular smooth muscle cell biology and lung airway reactivity, presented at the Experimental Biology/International Union of Physiological Sciences 2005 congress held in San Diego, California. "Integrin Ligands Mobilize Intracellular Calcium in Rat Pulmonary Arterial Smooth Muscle Cells (PASMCs)," by Anita Umesh, Kay-Pong Yip et al.; "Role of Pentose Phosphate Pathway (PPP) and NADPH Redox in Hypoxic Vasodilation," by Sachin A. Gupte and Michael S. Wolin; "Modulatory Effect of Vitamin E and C on Airway Hyperactivity (AHR) and Oxidant-Antioxidant Status in Sensitized, Challenged Pigs," by Sujata Upadhyay, K. Ravi et al.