Comparative analysis and directed protein evolution yield an improved degron technology with minimal basal degradation, rapid inducible depletion, and faster recovery of target proteins.

Biological mechanisms are inherently dynamic, requiring precise and rapid gene manipulation for effective characterization. Traditional genetic perturbation tools such as siRNA and CRISPR knockout operate on timescales that render them unsuitable for exploring dynamic processes or studying essential genes, where chronic depletion can lead to cell death. Here, we compared four major inducible degron systems-dTAG, HaloPROTAC, and two auxin-inducible degron (AID) tools-in human pluripotent stem cells.

Advancing aquaculture: Production of xenogenic catfish by transplanting blue catfish (Ictalurus furcatus) and channel catfish (I. punctatus) stem cells into white catfish (Ameiurus catus) triploid fry.

Xenogenesis has been recognized as a prospective method for producing channel catfish, Ictalurus punctatus ♀ × blue catfish, I. furcatus ♂ hybrids. The xenogenesis procedure can be achieved by transplanting undifferentiated stem cells derived from a donor fish into a sterile recipient.

From heterosis to outbreeding depression: genotype-by-environment interaction shifts hybrid fitness in opposite directions.

In F1 hybrids, phenotypic values are expected to be near the parental means under additive effects or close to one parent under dominance. However, F1 traits can fall outside the parental range, and outbreeding depression occurs when inferior fitness is observed in hybrids. Another possible outcome is heterosis, a phenomenon that interspecific hybrids or intraspecific crossbred F1s exhibit improved fitness compared to both parental species or strains.

CRISPR/Cas9-mediated knock-in of masu salmon (Oncorhyncus masou) elongase gene in the melanocortin-4 (mc4r) coding region of channel catfish (Ictalurus punctatus) genome.

Channel catfish, Ictalurus punctatus, have limited ability to synthesize Ω-3 fatty acids. The ccβA-msElovl2 transgene containing masu salmon, Oncorhynchus masou, elongase gene driven by the common carp, Cyprinus carpio, β-actin promoter was inserted into the channel catfish melanocortin-4 receptor (mc4r) gene site using the two-hit two-oligo with plasmid (2H2OP) method. The best performing sgRNA resulted in a knockout mutation rate of 92%, a knock-in rate of 54% and a simultaneous knockout/knock-in rate of 49%.

Genomic imprinting-like monoallelic paternal expression determines sex of channel catfish.

The X and Y chromosomes of channel catfish have the same gene contents. Here, we report allelic hypermethylation of the X chromosome within the sex determination region (SDR). Accordingly, the X-borne gene was silenced, whereas the Y-borne gene was expressed, making monoallelic expression of responsible for sex determination, much like genomic imprinting.

A New Strategy for Increasing Knock-in Efficiency: Multiple Elongase and Desaturase Transgenes Knock-in by Targeting Long Repeated Sequences.

CRISPR/Cas9-mediated knock-in (KI) has a wide application in gene therapy, gene function study, and transgenic breeding programs. Unlike gene therapy, which requires accurate KI to correct gene mutation, transgenic breeding programs can accept robust KI as long as integration does not interrupt normal gene functions and result in any negative pleiotropic effects. High KI efficiency is required to reduce the breeding cost and shorten the breeding period, especially in transferring multiple foreign genes to a single individual.

Improved Growth and High Inheritance of Melanocortin-4 Receptor (mc4r) Mutation in CRISPR/Cas-9 Gene-Edited Channel Catfish, Ictalurus punctatus.

Effects of CRISPR/Cas9 knockout of the melanocortin-4 receptor (mc4r) gene in channel catfish, Ictalurus punctatus, were investigated. Three sgRNAs targeting the channel catfish mc4r gene in conjunction with Cas9 protein were microinjected in embryos and mutation rate, inheritance, and growth were studied. Efficient mutagenesis was achieved as demonstrated by PCR, Surveyor® assay, and DNA sequencing.

Feminization of channel catfish with 17β-oestradiol involves methylation and expression of a specific set of genes independent of the sex determination region.

Exogenous oestrogen 17β-oestradiol (E2) has been shown to effectively induce feminization in teleosts. However, the molecular mechanisms underlying the process remain unclear. Here, we determined global DNA methylation and gene expression profiles of channel catfish () during early sex differentiation after E2 treatment.

Response of cecropin transgenesis to challenge with Edwardsiella ictaluri in channel catfish Ictalurus punctatus.

Constructs bearing the cecropin B gene from the moth Hyalophora cecropia, driven by the cytomegalovirus (CMV) promoter, or the common carp beta-actin (β-actin) promoter were transferred to channel catfish, Ictalurus punctatus via electroporation. One F channel catfish family transgenic for cecropin transgene driven by the CMV promoter, and one F channel catfish family transgenic for cecropin transgene driven by the common carp β-actin promoter were produced. F and F individuals exhibited enhanced disease resistance when challenged in tanks with Edwardsiella ictaluri, the causative agent of enteric septicemia of catfish (ESC).

CRISPR/Cas9-Mediated Transgenesis of the Masu Salmon (Oncorhynchus masou) elovl2 Gene Improves n-3 Fatty Acid Content in Channel Catfish (Ictalurus punctatus).

Omega-3 polyunsaturated fatty acids (n-3 PUFAs), particularly eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3), play a very important role in human health. Channel catfish (Ictalurus punctatus) is one of the leading freshwater aquaculture species in the USA, but has low levels of EPA and DHA compared to some fish such as salmon. To improve EPA and DHA content, a modification of the n-3 PUFA biosynthetic pathway was achieved through the insertion of an elovl2 transgene isolated from masu salmon (Oncorhynchus masou) driven by a carp β-actin promoter using a two-hit by gRNA and two oligos with a targeting plasmid (2H2OP) CRISPR/Cas9 approach.

CRISPR/Cas9-mediated knock-in of alligator cathelicidin gene in a non-coding region of channel catfish genome.

CRISPR/Cas9-based gene knockout in animal cells, particularly in teleosts, has proven to be very efficient with regards to mutation rates, but the precise insertion of exogenous DNA or gene knock-in via the homology-directed repair (HDR) pathway has seldom been achieved outside of the model organisms. Here, we succeeded in integrating with high efficiency an exogenous alligator cathelicidin gene into a targeted non-coding region of channel catfish (Ictalurus punctatus) chromosome 1 using two different donor templates (synthesized linear dsDNA and cloned plasmid DNA constructs). We also tested two different promoters for driving the gene, zebrafish ubiquitin promoter and common carp β-actin promoter, harboring a 250-bp homologous region flanking both sides of the genomic target locus.

Comparative Genomic and Transcriptomic Analyses Revealed Twenty-Six Candidate Genes Involved in the Air-Breathing Development and Function of the Bighead Catfish Clarias macrocephalus.

The bighead catfish (Clarias macrocephalus) and channel catfish (Ictalurus punctatus) are freshwater species in the Siluriformes order. C. macrocephalus has both gills and modified gill structures serving as an air-breathing organ (ABO), while I.

Development of a spermatogonia cryopreservation protocol for blue catfish, Ictalurus furcatus.

Sustainability of channel catfish, Ictalurus punctatus ♀ × blue catfish, Ictalurus furcatus ♂ hybrid aquaculture relies on new innovative technologies to maximize fry output. Transplanting spermatogonial stem cells (SSCs) from blue catfish into channel catfish hosts has the potential to greatly increase gamete availability and improve hybrid catfish fry outputs. Cryopreservation would make these cells readily accessible for xenogenesis, but a freezing protocol for blue catfish testicular tissues has not yet been fully developed.

Prognosis in patients with small hepatocellular carcinoma: a meta-analysis.

Background/aims: To evaluate the impact of anatomic and non-anatomic liver resection on prognosis of patients with small hepatocellular carcinoma (HCC) using a meta-analysis.

Methodology: Literature on anatomic versus non-anatomic liver resection for the treatment of small HCC published in public was retrieved.

Results: Four non-randomized controlled trials studies were included in this analysis.

Evodiamine, a constituent of Evodiae Fructus, induces anti-proliferating effects in tumor cells.

We found that evodiamine, a major alkaloidal component of Evodiae Fructus (Goshuyu in Japan), inhibited proliferation of several tumor cell lines, but had less effect on human peripheral blood mononuclear cells (PBMC). We used human cervical cancer cells, HeLa, as a model to elucidate the molecular mechanisms of evodiamine-induced tumor cell death. The results showed that evodiamine induced oligonucleosomal fragmentation of DNA in HeLa cells and increased the activity of caspase-3, but not that of caspase-1, in vitro.