PollenDetect: An Open-Source Pollen Viability Status Recognition System Based on Deep Learning Neural Networks.

Pollen grains, the male gametophytes for reproduction in higher plants, are vulnerable to various stresses that lead to loss of viability and eventually crop yield. A conventional method for assessing pollen viability is manual counting after staining, which is laborious and hinders high-throughput screening. We developed an automatic detection tool (PollenDetect) to distinguish viable and nonviable pollen based on the YOLOv5 neural network, which is adjusted to adapt to the small target detection task. Compared with manual work, PollenDetect significantly reduced detection time (from approximately 3 min to 1 s for each image). Meanwhile, PollenDetect can maintain high detection accuracy. When PollenDetect was tested on cotton pollen viability, 99% accuracy was achieved. Furthermore, the results obtained using PollenDetect show that high temperature weakened cotton pollen viability, which is highly similar to the pollen viability results obtained using 2,3,5-triphenyltetrazolium formazan quantification. PollenDetect is an open-source software that can be further trained to count different types of pollen for research purposes. Thus, PollenDetect is a rapid and accurate system for recognizing pollen viability status, and is important for screening stress-resistant crop varieties for the identification of pollen viability and stress resistance genes during genetic breeding research.

Environmental stresses induce karyotypic instability in colorectal cancer cells.

Understanding how cells acquire genetic mutations is a fundamental biological question with implications for many different areas of biomedical research, ranging from tumor evolution to drug resistance. While karyotypic heterogeneity is a hallmark of cancer cells, few mutations causing chromosome instability have been identified in cancer genomes, suggesting a nongenetic origin of this phenomenon. We found that in vitro exposure of karyotypically stable human colorectal cancer cell lines to environmental stress conditions triggered a wide variety of chromosomal changes and karyotypic heterogeneity. At the molecular level, hyperthermia induced polyploidization by perturbing centrosome function, preventing chromosome segregation, and attenuating the spindle assembly checkpoint. The combination of these effects resulted in mitotic exit without chromosome segregation. Finally, heat-induced tetraploid cells were on the average more resistant to chemotherapeutic agents. Our studies suggest that environmental perturbations promote karyotypic heterogeneity and could contribute to the emergence of drug resistance.