SRD-1 in AWA neurons is the receptor for female volatile sex pheromones in males.

Pheromones are critical cues for attracting mating partners for successful reproduction. Sexually mature virgin females and self-sperm-depleted hermaphrodites produce volatile sex pheromones to attract adult males of both species from afar. The chemoresponsive receptor in males has remained unknown.

Comparative analysis of single-cell parallel sequencing approaches in oocyte application.

Single-cell parallel sequencing allows us to explore how genetic and epigenetic variations correlate of gene expression in the same cell. Beads-based approach and non-beads-based approach are the two present methods to separate DNA and RNA from the same cell. However, systematic difference between the two methods are lacking.

Generation and characterization of pathogenic Mab21l2(R51C) mouse model.

MAB21L2(R51C) is one of the five documented MAB21L2 mutations in human patients with bilateral eye malformations identified via whole exome sequencing. In addition to the eye abnormality, patients with MAB21L2 mutation also have skeletal dysplasia and intellectual disability. To evaluate the pathology of this mutant allele systematically in understanding the functional role of MAB21L2 in human development, we introduce the R51C mutation into the mouse genome by CRISPR/Cas9 system to generate a mouse model for detailed characterization.

Hepatoma-intrinsic CCRK inhibition diminishes myeloid-derived suppressor cell immunosuppression and enhances immune-checkpoint blockade efficacy.

Objective: Myeloid-derived suppressor cells (MDSCs) contribute to tumour immunosuppressive microenvironment and immune-checkpoint blockade resistance. Emerging evidence highlights the pivotal functions of cyclin-dependent kinases (CDKs) in tumour immunity. Here we elucidated the role of tumour-intrinsic CDK20, or cell cycle-related kinase (CCRK) on immunosuppression in hepatocellular carcinoma (HCC).

ICA1L forms BAR-domain complexes with PICK1 and is crucial for acrosome formation in spermiogenesis.

Mutations in the Pick1 gene cause globozoospermia, a male infertility disorder, in both mice and humans. PICK1 is crucial for vesicle trafficking, and its deficiency in sperm cells leads to abnormal vesicle trafficking from the Golgi to the acrosome. This eventually disrupts acrosome formation and leads to male infertility.

Systems-level quantification of division timing reveals a common genetic architecture controlling asynchrony and fate asymmetry.

Coordination of cell division timing is crucial for proper cell fate specification and tissue growth. However, the differential regulation of cell division timing across or within cell types during metazoan development remains poorly understood. To elucidate the systems-level genetic architecture coordinating division timing, we performed a high-content screening for genes whose depletion produced a significant reduction in the asynchrony of division between sister cells (ADS) compared to that of wild-type during Caenorhabditis elegans embryogenesis.

Tackling codon usage bias for heterologous expression in Rhodobacter sphaeroides by supplementation of rare tRNAs.

The photosynthetic Rhodobacter species are promising alternative expression hosts in bioproduction and biorefinery due to their unique metabolic capacities. With prominent inner membrane areas and efficient endogenous translocation machineries, they are especially attractive for membrane protein expression. However, codon usage bias could be a limitation in the engineering of Rhodobacter species and has seldom been investigated.

Three-dimensional self-assembling peptide matrix enhances the formation of embryoid bodies and their neuronal differentiation.

We have tailored the properties of a self-assembling peptide (SAP) matrix to direct embryonic stem cells towards neuronal differentiation by adopting a three-dimensional (3D) culture, matching mechanical strength with that of neural tissue, and incorporating fixed laminin-derived pentapeptide signals (IKVAV). We report here that such a matrix alone can induce mouse embryonic stem (ES) cells to first develop into embryoid body (EB) and increase their propensity for subsequent neuronal differentiation. Embryoid bodies were observed by day 5 of culture in SAP matrix.

SEM sample preparation for cells on 3D scaffolds by freeze-drying and HMDS.

Common dehydration methods of cells on biomaterials for scanning electron microscopy (SEM) include air drying, hexamethyldisilazane (HMDS) or tetramethysilane (TMS) treatment and critical point drying (CPD). On the other side, freeze-drying has been widely employed in dehydrating biological samples and also in preparing porous biomaterial scaffolds but not in preparing cells on three-dimensional (3D) biomaterials for SEM examination. In this study, we compare cells on porous hydroxyapatite (HA) prepared by air drying, HMDS and freeze-drying.

Factorial analysis of adaptable properties of self-assembling peptide matrix on cellular proliferation and neuronal differentiation of pluripotent embryonic carcinoma.

Unlabelled: An integrative and quantitative approach for systematically studying the effects of changing the matrix environment on pluripotent cell viability and neuronal differentiation was demonstrated. This approach, based on factorial analysis and a self-assembling peptide (SAP) matrix, was exemplified using P19 as a pluripotent cell model. In a two-level, three-factor factorial design of experiments, three niche factors, namely, culture dimensionality, fixed biochemical signal and mechanical stiffness, were simultaneously investigated.

Cell culture medium as an alternative to conventional simulated body fluid.

Simulated body fluid (SBF) has been widely used for bioactivity assessment of biomaterials. Many different recipes have been developed, but there is still room for improvement. We have suggested the use of cell culture medium to overcome the drawbacks of conventional SBF.

Is macroporosity absolutely required for preliminary in vitro bone biomaterial study? A comparison between porous materials and flat materials.

Porous materials are highly preferred for bone tissue engineering due to space for blood vessel ingrowth, but this may introduce extra experimental variations because of the difficulty in precise control of porosity. In order to decide whether it is absolutely necessary to use porous materials in in vitro comparative osteogenesis study of materials with different chemistries, we carried out osteoinductivity study using C3H/10T1/2 cells, pluripotent mesenchymal stem cells (MSCs), on seven material types: hydroxyapatite (HA), α-tricalcium phosphate (α-TCP) and b-tricalcium phosphate (β-TCP) in both porous and dense forms and tissue culture plastic. For all materials under test, dense materials give higher alkaline phosphatase gene (Alp) expression compared with porous materials.

Immediately sequential bilateral cataract surgery versus delayed sequential bilateral cataract surgery: potential hospital cost savings.

Objective: Cataract surgery represents a substantial cost to health care systems around the world. Canada's socialized medical system allows an opportunity to accurately track costing because of the institutional record keeping necessary for public reporting to provincial governments. Cataract surgical costs consist of medical costs, hospital costs, and social costs.

Cryopreservation of mammalian embryos: Advancement of putting life on hold.

Rodent transgenesis and human-assisted reproductive programs involve multistep handling of preimplantation embryos. The efficacy of production and quality of results from conventionally scheduled programs are limited by temporal constraints other than the quality and quantities of embryos per se. The emergence of vitrification, a water ice-free cryopreservation technique, as a reliable way to arrest further growth of preimplantation embryos, provides an option to eliminate the time constraint.

mab-31 and the TGF-beta pathway act in the ray lineage to pattern C. elegans male sensory rays.

Background: C. elegans TGF-beta-like Sma/Mab signaling pathway regulates both body size and sensory ray patterning. Most of the components in this pathway were initially identified by genetic screens based on the small body phenotype, and many of these mutants display sensory ray patterning defect.

Mouse embryo cryopreservation utilizing a novel high-capacity vitrification spatula.

Embryo cryopreservation is an indispensable technique in reproductive programs and in animal facilities where genetically modified mice are used extensively. Here we report the use of a vitrification spatula (VS) that can be readily homemade and has a large holding capacity to vitrify preimplantation mammalian embryos in a micro-drop employing ultra-rapid cooling in liquid nitrogen (LN2). Vitrified one-cell embryos and morulae have high survival rates after thawing, and the fertility of the derived progeny is comparable to that of the control unvitrified group.

Study of hydroxyapatite osteoinductivity with an osteogenic differentiation of mesenchymal stem cells.

Osteoinductivity of hydroxyapatite (HA) was investigated using uncommitted pluripotent mouse stem cells, C3H10T1/2 in an in vitro differentiation assay. For comparative analysis, the cells were cultured on substrates made of osteoinductive HA, with biocompatible titanium and plastics as the negative control. HA exhibited the ability to induce expression of osteo-specific genes in C3H10T1/2, including alkaline phosphatase (ALP), type I collagen, and osteocalcin; compared with its insignificant up-regulation of the same genes in osteoblast-like cells, Saos-2.

Improvement of heavy metal stress and toxicity assays by coupling a transgenic reporter in a mutant nematode strain.

Previous studies have demonstrated that wild type Caenorhabditis elegans displays high sensitivity to heavy metals in a lethality test at a level comparable to that of other bioindicator organisms. Taking advantage of the genetics of this model organism, we have tested a number of mutant strains for enhanced sensitivity in heavy metal induced lethality and stress response. These mutants are defective in genes controlling dauer formation, longevity or response to reactive oxygen species (ROS).

A mutation at the start codon defines the differential requirement of dpy-11 in Caenorhabditis elegans body hypodermis and male tail.

dpy-11 encodes a thioredoxin-like molecule that is important for both body and male sensory ray morphogenesis in Caenorhabditis elegans. A mutant allele, s287, has a point mutation with its start codon, AUG, converted into AUA, presumably leading to null function. Since only a weak loss-of-function phenotype was observed, we tested whether an alternative start codon or the converted AUA could be used for translation initiation with reduced efficiency.

Synergistic toxicity of multiple heavy metals is revealed by a biological assay using a nematode and its transgenic derivative.

Caenorhabditis elegans, a free-living nematode species, was adopted for a toxicity bioassay of 10 heavy metals. The lethal concentration (LC) of these metals was determined. Based on these data, we conducted pairwise and triple metal combination testing and demonstrated that these heavy metals displayed synergistic killing effects on C.

Expression of zebrafish mab21 genes marks the differentiating eye, midbrain and neural tube.

Mab21 homolog in Caenorhabditis elegans is expressed in the sensory ray cells and determines the ray identity (Dev. Dyn. 221 (2001) 422).