Biology subjects

Rosenberg, N.

Publications and source records attributed to Rosenberg, N..

3 recordsLinked to original sources

bioRxiv2023

Unraveling the Genomic Diversity and Evolutionary History of Captive Tigers in the United States

Genomic studies of rare and endangered species have focused broadly on describing diversity patterns and resolving phylogenetic relationships, with the overarching goal of informing conservation efforts. However, few studies have investigated the genomic diversity potentially housed in captive populations. For tigers (Panthera tigris) in particular, captive individuals vastly outnumber those in the wild, yet the diversity of the captive population remains largely unexplored. Here, we present the first large-scale genetic study of the private (non-zoo) captive tiger population in the United States (U.S.), also known as Generic tigers. We find that the U.S. Generic tiger population has an admixture fingerprint comprising all six extant wild tiger subspecies (P. t. altaica, Amur; P. t. tigris, Bengal; P. t. corbetti, Indochinese; P. t. jacksoni, Malayan; P. t. amoyensis, South China; P. t. sumatrae, Sumatran). We show that the Generic tiger population has a comparable amount of genetic diversity to most wild subspecies, relatively few private variants, and fewer deleterious mutations. We also observe inbreeding coefficients that are similar to wild populations, suggesting that inbreeding in captive populations is not pervasive, although there are some individuals within the Generic population that are substantially inbred. Our results elucidate the admixture history of the Generic tiger population in the U.S. Additionally, we develop a reference panel for tigers and show that it can be used with imputation to accurately distinguish individuals and assign ancestry even with ultra-low coverage (0.25x) data. The study and reference panel will provide a resource to assist in tiger conservation efforts.

evolutionary biology↗

bioRxiv2022

Using the glial mitochondrial machinery to prevent multilevel dysfunctions observed in a mouse model of Alzheimer s disease

Alzheimers disease (AD) is becoming increasingly prevalent worldwide. It represents one of the greatest medical challenge as no pharmacologic treatments are available to prevent disease progression. Astrocytes play crucial functions within neuronal circuits by providing metabolic and functional support, regulating interstitial solute composition, and modulating synaptic transmission. In addition to these physiological functions, growing evidence points to an essential role of astrocytes in neurodegenerative diseases like AD. Early stage AD is associated with hypometabolism and oxidative stress. Contrary to neurons that are vulnerable to oxydative stress, astrocytes are particularly resistant to mitochondrial dysfunction and are therefore more resilient cells. In our study, we leveraged astrocytic mitochondrial uncoupling and examined neuronal function in the 3xTg AD mouse model. We overexpressed the mitochondrial uncoupling protein 4 (UCP4), which has been shown to improve neuronal survival in vitro. We found that this treatment efficiently prevented alterations of hippocampal metabolite levels observed in AD mice, along with hippocampal atrophy and reduction of basal dendrite arborization of subicular neurons. This approach also averted aberrant neuronal excitability observed in AD subicular neurons and preserved episodic-like memory in AD mice assessed in a spatial recognition task. These findings show that targeting astrocytes and their mitochondria is an effective strategy to prevent the decline of neurons facing AD-related stress at the early stages of the disease.

neuroscience↗

bioRxiv2018

Determination of biophysical parameters for enhancement of human osteoblast proliferation by mechanical vibration in the infrasonic frequency range

Experimental methods for studying an enhancement of osteoblast proliferation in vitro provide tools for the research of biochemical processes involved in bone turnover in vivo. Some of the current methods used for this purpose are based on the ability of the osteoblasts to enhance proliferation by mechanical stimulation. We describe an experimental approach of biomechanical stimulation of cultured human osteoblast-like cells by vibration. This method is based on the specially designed controlled vibration setup that consists of an electric actuator, with horizontally mounted well plate containing cell cultures. Previously this method found to be effective to enhance cell proliferation, but the exact mechanical parameters of effective vibration were elusive. The current low friction system for mechanical stimulation of osteoblast-like cells in vitro provides recording of narrow range mechanical parameters in the infrasonic spectrum.\n\nWe exposed human osteoblast-like cells in explant monolayer culture to mechanical vibration in the 10-70Hz range of frequencies and found that 50-70 Hz of vibration frequency is optimal for inducing osteoblast proliferation that was deduced from interrelation between unchanged cell number in culture samples with significant decrease in cell death rate (decreased LDH activity in culture media, p<.05) and with parallel decrease of their maturation level (p<.01).\n\nIn this report we determined the optimal mechanical parameters and excitation protocol for induction of osteoblast proliferation in vitro by using a tunable and versatile mechanical platform, which can be used in the research of cell mechanotransduction.

cell biology↗