New Late Pleistocene age for the Homo sapiens skeleton from Liujiang southern China.

The emergence of Homo sapiens in Eastern Asia is a topic of significant research interest. However, well-preserved human fossils in secure, dateable contexts in this region are extremely rare, and often the subject of intense debate owing to stratigraphic and geochronological problems. Tongtianyan cave, in Liujiang District of Liuzhou City, southern China is one of the most important fossils finds of H. sapiens, though its age has been debated, with chronometric dates ranging from the late Middle Pleistocene to the early Late Pleistocene. Here we provide new age estimates and revised provenience information for the Liujiang human fossils, which represent one of the most complete fossil skeletons of H. sapiens in China. U-series dating on the human fossils and radiocarbon and optically stimulated luminescence dating on the fossil-bearing sediments provided ages ranging from ~33,000 to 23,000 years ago (ka). The revised age estimates correspond with the dates of other human fossils in northern China, at Tianyuan Cave (~40.8-38.1 ka) and Zhoukoudian Upper Cave (39.0-36.3 ka), indicating the geographically widespread presence of H. sapiens across Eastern Asia in the Late Pleistocene, which is significant for better understanding human dispersals and adaptations in the region.

Hormesis effects in tomato plant growth and photosynthesis due to acephate exposure based on physiology and transcriptomic analysis.

BACKGROUND: Hormesis is a common phenomenon in toxicology described as low-dose stimulation due to a toxin which causes inhibition at a high dose. Pesticide hormesis in plants has attracted considerable research interest in recent years; however, the specific mechanism has not yet been clarified. Acephate is an organophosphorus insecticide that is used worldwide. Here, hormesis in tomato (Solanum lycopersicum L.) plant growth and photosynthesis after acephate exposure is confirmed, as stimulation occurred at low stress levels, whereas inhibition occurred after exposure to high concentrations. RESULTS: We found that low acephate concentration (5-fold lower than recommended application dosage) could enhance chlorophyll biosynthesis and stimulate photosynthesis effects, and thus improve S. lycopersicum growth. A high level of acephate (5-fold higher than recommended application dosage) stress inhibited chlorophyll accumulation, decreased photosystem II efficiency and blocked antioxidant reactions in leaves, increasing reactive oxygen species levels and damaging plant growth. Transcriptomic analysis and quantitative real-time PCR results revealed that the photosynthesis - antenna proteins pathway played a crucial role in the hormesis effect, and that LHCB7 as well as LHCP from the pathway were the most sensitive to acephate hormesis. CONCLUSION: Our results showed that acephate could induce hormesis in tomato plant growth and photosynthesis, and that photosystem II and the photosynthesis - antenna proteins pathway played important roles in hormesis. These results provide novel insights into the scientific and safe application of chemical pesticides, and new guidance for investigation into utilizing pesticide hormesis in agriculture. © 2023 Society of Chemical Industry.

Function of four mitochondrial genes in fumigation lethal mechanisms of Allyl Isothiocyanate against Sitophilus zeamais adults.

Allyl isothiocyanate (AITC) is a promising alternative to chemical fumigants, and mitochondrial dysfunction has been proposed to play a crucial role in its lethal mechanisms; however, the specific lethal mechanisms of AITC remain unknown. Four mitochondrial electron transport chain genes, nd5, nd6, cox1, and cox5, were selected from adult Sitophilus zeamais and processed with RNA interference experiments. Then, the biochemical and biophysical effects were compared between double-stranded RNA (dsRNA)-mediated insects and wild-type insects after AITC fumigation at the concentration of LC50 values. The bioactivity of AITC against dsnd6-mediated insects increased, while the bioactivity against dcox1-mediated insects decreased. Compared with the wild-type insects, the increase of reactive oxygen species (ROS) levels by AITC in mitochondria from dsnd6-mediated insects increased by 18.95%, while that of dscox1-mediated insects decreased by 27.45%. The effects of AITC on mRNA expression levels of detoxifying enzymes including CAT (down-regulation effect) and CuZnSOD (overexpression effect) partly recovered in the dsnd5-mediated insects, while a greater effect was observed for dscox1-mediated insects. Molecular docking results indicated that ASN511 at the cox1 subunit was the binding site of AITC by one hydrogen bond, with a bond distance of 2.1 Å. These findings provide insight for further applications of AITC and could provide a novel strategy to investigate lethal mechanisms of insecticides.