Lake Superior State University

Aeromonas hydrophila (AH) is a pathogenic bacterium commonly found in aquatic organisms, particularly in fish products. Baicalein, a bioactive flavonoid derived from traditional Chinese herbal medicine, possesses a wide range of pharmacological properties, including anticancer, antibacterial, antiviral, antioxidant, hepatoprotective, and anti-inflammatory effects. In vitro, the Oxford cup method was employed to assess the antibacterial activity of baicalein, while the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined using the microtiter broth dilution technique. Biofilm formation and bacterial motility were evaluated through the crystal violet assay and swimming assay, respectively. The impact of baicalein on bacterial membrane permeability and morphology was observed using the Live/Dead BacLight kit and transmission electron microscopy. In vivo, grass carp were used as the model organism to evaluate the effect of baicalein on AH proliferation, while the expression of pro-inflammatory cytokines and antioxidant factors was quantified by qRT-PCR. This study demonstrated the antibacterial activity of baicalein against AH infection. Baicalein exhibited bacteriostatic effects in vitro, with an MIC of 40 μg/mL and an MBC of 80 μg/mL. Time-kill assays confirmed its bactericidal properties. Additionally, baicalein inhibited biofilm formation and reduced bacterial motility. The antibacterial mechanism of baicalein involved increased membrane permeability and structural disruption of AH cells. In vivo studies in grass carp revealed a dose-dependent reduction in AH burden following baicalein administration. Moreover, baicalein suppressed the expression of pro-inflammatory cytokines, including interleukin-1β (IL-1β), interleukin-8 (IL-8), and tumor necrosis factor-α (TNF-α), while enhancing the expression of antioxidant-related genes, such as catalase (CAT), glutathione reductase (GR), and superoxide dismutase (SOD). These findings indicate that the antibacterial and anti-inflammatory effects of baicalein contribute to its protective role against AH infection in vivo. Baicalein effectively inhibits the proliferation of AH both in vitro and in vivo, highlighting its potential as a promising pharmacotherapeutic agent for the prevention of AH infections in fish.

A Shigella podophage, Moonfish, was isolated from a longhorn cattle ranch in Barry County, MI, USA. The 69,166-bp genome was annotated and places Moonfish in a similar category to N4-like phages. Host range studies show that Moonfish has a narrow host profile relative to similar phages.

1.AbstractFreshwater sponges fulfill critical ecological functions, including maintaining water quality, regulating nutrient dynamics, offering habitats for diverse taxa, and serving as a vital food source for various species. However, their patterns of dispersal and genetic connectivity remain inadequately understood, posing significant challenges to effective conservation assessments. We examined genetic connectivity and genetic adaptation to local environmental conditions inEphydatia muelleriacross its geographic range using ddRADseq-derived SNPs from 106 individuals collected from 11 localities spanning North America, Europe, and Asia. Analysis of 3,182 neutral SNPs revealed low connectivity and strong genetic structure among regions within two main genetic clusters of North America and Eurasia, while 115 SNPs identified to be under selection showed considerable evidence for differentiated, polygenic adaptation to light and temperature conditions across sampled locations, as well as selection on gene regulatory processes. These findings align with the “monopolization hypothesis”, suggesting that historical climatic and geological conditions of the Last Glacial Maximum, including habitat expansion, contraction, and natural barriers, have contributed more to the current genetic structure ofE. muelleripopulations than contemporary gene flow, which is restricted by monopolistic habitat colonization by this species. Our results provide novel support for ecological theory on dispersal in aquatic invertebrates, as well as insights into the plasticity ofE. muelleriin the face of varying environmental conditions that are fundamentally important for freshwater ecosystem conservation.