Biology subjects

Parenti, L. R.

Publications and source records attributed to Parenti, L. R..

3 recordsLinked to original sources

bioRxiv2025

Estimating Historical Food Web Variation in Chesapeake Bay Using Isotope Variation in Museum Fish Specimens

Trophic interactions are hypothesized to change in response to rapid anthropogenic environmental changes. Documenting these trends may aid biological conservation. One tool to measure trophic level is stable isotope analysis. Nitrogen isotope values ({delta}15N) of bulk tissue may be used as indirect indicators of an organisms trophic level and the isotopic composition of its prey. In contrast, compound-specific isotope analysis can estimate trophic level directly. For the fishes of Chesapeake Bay, museum collections provide a unique opportunity to characterize trophic trends collected as early as the 1850s, from an ecosystem that has been overfished and subjected to increasingly high nutrient loading and land use change during the past three centuries. To assess isotope data for evidence of change in predator species trophic level, we analyzed tissue from 183 museum specimens of three predators (Striped Bass, Morone saxatilis; Summer Flounder, Paralichthys dentatus; and Bluefish, Pomatomus saltatrix) and two lower-trophic-level species (Bay Anchovy, Anchoa mitchilli; and Menhaden, Brevoortia tyrannus). Predatory Striped Bass did not show an increase through time in {delta}15N values, despite such a trend in Bay Anchovy, suggesting possible change in trophic level. Analysis of Striped Bass tissue using compound specific analysis indicates their mean trophic level has been stable for decades. These findings imply that Striped Bass are part of a diverse food web within Chesapeake Bay beyond that reflected by our two included prey species and are stable through time in their average size-specific trophic level, a valuable insight into their ecological role.

ecology↗

bioRxiv2024

The axillary lymphoid organ - an external, experimentally accessible immune organ in the zebrafish

Lymph nodes and other secondary lymphoid organs play critical roles in immune surveillance and immune activation in mammals, but the deep internal locations of these organs make it challenging to image and study them in living animals. Here, we describe a previously uncharacterized external immune organ in the zebrafish ideally suited for studying immune cell dynamics in vivo, the axillary lymphoid organ (ALO). This small, translucent organ has an outer cortex teeming with immune cells, an inner medulla with a mesh-like network of fibroblastic reticular cells along which immune cells migrate, and a network of lymphatic vessels draining to a large adjacent lymph sac. Noninvasive high-resolution imaging of transgenically marked immune cells can be carried out in the lobes of living animals, and the ALO is readily accessible to external treatment. This newly discovered tissue provides a superb model for dynamic live imaging of immune cells and their interaction with pathogens and surrounding tissues, including blood and lymphatic vessels. TeaserA newly characterized external zebrafish lymphoid organ provides a powerful model for live imaging of immune cell dynamics

developmental biology↗

bioRxiv2021

The critical role of natural history museums in advancing eDNA for biodiversity studies: a case study with Amazonian fishes

Ichthyological surveys have traditionally been conducted using whole-specimen, capture-based sampling with varied, but conventional fishing gear. Recently, environmental DNA (eDNA) metabarcoding has emerged as a complementary, and possible alternative, approach to whole-specimen methodologies. In the tropics, where much of the diversity remains undescribed, vast reaches continue unexplored, and anthropogenic activities are constant threats; there have been few eDNA attempts for ichthyological inventories. We tested the discriminatory power of eDNA using MiFish primers with existing public reference libraries and compared this with capture-based methods in two distinct ecosystems in the megadiverse Amazon basin. In our study, eDNA provided an accurate snapshot of the fishes at higher taxonomic levels and corroborated its effectiveness to detect specialized fish assemblages. Some flaws in fish metabarcoding studies are routine issues addressed in natural history museums. Thus, by expanding their archives to include eDNA and adopting a series of initiatives linking collection-based research, training and outreach, natural history museums can enable the effective use of eDNA to survey Earths hotspots of biodiversity before taxa go extinct. Our project surveying poorly explored rivers and using DNA vouchered archives to build metabarcoding libraries for Neotropical fishes can serve as a model of this protocol.

ecology↗