Expression of cadR Enhances its Specific Activity for Cd Detoxification and Accumulation in Arabidopsis.

Cadmium (Cd) is a transition metal that is highly toxic in biological systems. Anthropogenic emissions of Cd have increased biogeochemical cycling and the amount of Cd in the biosphere. Here we studied the utility of a bacterial Cd-binding protein, CadR, for the remediation of Cd contamination. CadR was successfully targeted to chloroplasts using a constitutive Cauliflower mosaic virus (CaMV) 35S promoter or a shoot-specific Chl a/b-binding protein 2 gene (CAB2) promoter and an RbcS (small subunit of the Rubisco complex) transit peptide. Under short-term (2 d) exposure to Cd, the cadR transgenic plants showed up to a 2.9-fold Cd accumulation in roots compared with untransformed plants. Under medium term (7 d) exposure to Cd, the concentrations of Cd in leaves began to increase but there were no differences between the wild type and the cadR transgenic plants. Under long-term (16 d) exposure to Cd, the cadR transgenic plants accumulated greater amounts of Cd in leaves than the untransformed plants. Total Cd accumulation (µg per plant) in shoots and roots of the plants expressing cadR were significantly higher (up to 3.5-fold in shoots and 5.2-fold in roots) than those of the untransformed plants. We also found that targeting CadR to chloroplasts facilitated chloroplastic metal homeostasis and Chl b accumulation. Our results demonstrate that manipulating chelating capacity in chloroplasts or in the cytoplasm may be effective in modifying both the accumulation of and resistance to Cd.

China's policies: post-COVID-19 challenges for the older population.

On 7 December 2022, the State Council of China released 'Measures to Further Optimize the Implementation of the Prevention and Control of the New Coronavirus Epidemic'. The previous three-year dynamic zero epidemic prevention policy was then replaced with a full liberalization policy. On 5 May 2023, the World Health Organization declared that COVID-19 no longer constituted a 'public health emergency of international concern.' However, given the ongoing prevalence of coronavirus, emerging mutations, and the liberalization of restrictions, there are increased risks of vulnerable people contracting new variants. Low vaccination coverage among older people with compromised immune systems, puts them at further risk. The policy shift will increase pressure on already stretched health infrastructure and medical resources. This short article adds to the current debate arguing that the Chinese government should take commensurate preventive measures, including strengthening medical facilities and equipment and targeting ongoing vaccination in older people.

Paper ContextThe COVID-19 pandemic has disproportionately affected older people.This short paper discusses the consequences of China's liberalization policy on the older population.It suggests that the Chinese government should have taken targeted measures to mitigate health risks occurring under the changed circumstances.

Underlying metastasis mechanism and clinical application of exosomal circular RNA in tumors (Review).

Circular RNA (circRNA) is a long non­coding RNA molecule with a closed loop structure lacking a 5'cap and 3'tail. circRNA is stable, difficult to cleave and resistant to RNA exonuclease or RNase R degradation. circRNA molecules have several clinical applications, especially in tumors. For instance, circRNA may be used for non­invasive diagnosis, therapy and prognosis. Exosomes play a crucial role in the development of tumors. Exosomal circRNA in particular has led to increased research interest into tumorigenesis and tumor progression. Additionally, exosomal circRNA plays a role in cell­cell communication. Exosomal circRNA facilitates tumor metastasis by altering the tumor microenvironment and the pre­metastatic niche. Additionally, studies have revealed the mechanism by which exosomal circRNA affects malignant progression through signal transduction. Moreover, exosomal circRNA promotes tumor metastasis by regulating gene expression, RNA transcription and protein translation. In this review, the biological features and clinical application of exosomal circRNA are described, highlighting the underlying mechanisms through which they regulate tumor metastasis. The application of circRNA as clinical diagnostic biomarkers and in the development of novel therapeutic strategies is also discussed.

Disarrangement of actin filaments and Ca²âº gradient by CdCl2 alters cell wall construction in Arabidopsis thaliana root hairs by inhibiting vesicular trafficking.

Cadmium (Cd), one of the most toxic heavy metals, inhibits many cellular and physiological processes in plants. Here, the involvement of cytoplasmic Ca²âº gradient and actin filaments (AFs) in vesicular trafficking, cell wall deposition and tip growth was investigated during root (hair) development of Arabidopsis thaliana in response to CdCl2 treatment. Seed germination and root elongation were prevented in a dose- and time-dependent manner by CdCl2 treatment. Fluorescence labelling and non-invasive detection showed that CdCl2 inhibited extracellular Ca²âº influx, promoted intracellular Ca²âº efflux, and disturbed the cytoplasmic tip-focused Ca²âº gradient. In vivo labelling revealed that CdCl2 modified actin organization, which subsequently contributed to vesicle trafficking. Transmission electron microscopy revealed that CdCl2 induced cytoplasmic vacuolization and was detrimental to organelles such as mitochondria and endoplasmic reticulum (ER). Finally, immunofluorescent labelling and Fourier transform infrared (FTIR) analysis indicated that configuration/distribution of cell wall components such as pectins and cellulose was significantly altered in response to CdCl2. Our results indicate that CdCl2 induces disruption of Ca²âº gradient and AFs affects the distribution of cell wall components in root hairs by disturbing vesicular trafficking in A. thaliana.