Three species of rape responded to cadmium and melatonin alleviating Cd-toxicity in species-specific strategy.

Cadmium (Cd) pollution has been a significant concern in heavy metal pollution, prompting plants to adopt various strategies to mitigate its damage. While the response of plants to Cd stress and the impact of exogenous melatonin has received considerable attention, there has been limited focus on the responses of closely related species to these factors. Consequently, our investigation aimed to explore the response of three different species of rape to Cd stress and examine the influence of exogenous melatonin in this scenario. The research findings revealed distinctive responses among the investigated rape species. B. campestris showed the resistance to Cd and exhibited lower Cd absorption and sustained its physiological activity under Cd stress. In contrast, B. juncea accumulated much Cd and increased the amount of anthocyanin to mitigate the Cd-damage. Furthermore, B. napus showed the tolerance to Cd and tended to accumulate Cd in vacuoles under Cd stress, thereby decreasing the Cd damage and leading to higher activity of antioxidant enzymes and photosynthesis. Moreover, the application of exogenous melatonin significantly elevated the melatonin level in plants and mitigated Cd toxicity by promoting the activity of antioxidant enzymes, reducing Cd absorption, enhancing the chelating capacity with Cd, decreasing Cd accumulation in organelles, and reducing its fluidity. Specifically, exogenous melatonin increased the FHAc content in B. campestris, elevated the phytochelatins (PCs) level in B. napus, and stimulated photosynthesis in B. juncea. In summary, the findings underscore the species-specific responses of the three species of rape to both Cd stress and exogenous melatonin, highlighting the potential for tailored mitigation strategies based on the unique characteristics of each species.

Targeting ST8SIA6-AS1 counteracts KRASG12C inhibitor resistance through abolishing the reciprocal activation of PLK1/c-Myc signaling.

BACKGROUND: KRASG12C inhibitors (KRASG12Ci) AMG510 and MRTX849 have shown promising efficacy in clinical trials and been approved for the treatment of KRASG12C-mutant cancers. However, the emergence of therapy-related drug resistance limits their long-term potential. This study aimed to identify the critical mediators and develop overcoming strategies. METHODS: By using RNA sequencing, RT-qPCR and immunoblotting, we identified and validated the upregulation of c-Myc activity and the amplification of the long noncoding RNA ST8SIA6-AS1 in KRASG12Ci-resistant cells. The regulatory axis ST8SIA6-AS1/Polo-like kinase 1 (PLK1)/c-Myc was investigated by bioinformatics, RNA fluorescence in situ hybridization, RNA immunoprecipitation, RNA pull-down and chromatin immunoprecipitation. Gain/loss-of-function assays, cell viability assay, xenograft models, and IHC staining were conducted to evaluate the anti-cancer effects of co-inhibition of ST8SIA6-AS1/PLK1 pathway and KRAS both in vitro and in vivo. RESULTS: KRASG12Ci sustainably decreased c-Myc levels in responsive cell lines but not in cell lines with intrinsic or acquired resistance to KRASG12Ci. PLK1 activation contributed to this ERK-independent c-Myc stability, which in turn directly induced PLK1 transcription, forming a positive feedback loop and conferring resistance to KRASG12Ci. ST8SIA6-AS1 was found significantly upregulated in resistant cells and facilitated the proliferation of KRASG12C-mutant cancers. ST8SIA6-AS1 bound to Aurora kinase A (Aurora A)/PLK1 and promoted Aurora A-mediated PLK1 phosphorylation. Concurrent targeting of KRAS and ST8SIA6-AS1/PLK1 signaling suppressed both ERK-dependent and -independent c-Myc expression, synergistically led to cell death and tumor regression and overcame KRASG12Ci resistance. CONCLUSIONS: Our study deciphers that the axis of ST8SIA6-AS1/PLK1/c-Myc confers both intrinsic and acquired resistance to KRASG12Ci and represents a promising therapeutic target for combination strategies with KRASG12Ci in the treatment of KRASG12C-mutant cancers.

New insights into the role of melatonin in photosynthesis.

There are numerous studies on enhancing plant resistance to stress using melatonin, but few studies about its effect on photosynthesis. Herein, we summarized the role of melatonin in photosynthesis. Melatonin regulates chlorophyll synthesis and degradation through the transcription of related genes and hormone signals. It protects photosynthetic proteins and maintains the photosynthetic process through improving the transcription of photosystem genes, activating the antioxidant system, and promoting the xanthophyll cycle. Melatonin potentially regulates plant stomatal movement through CAND2/PMTR1. Finally, it controls the photosynthetic carbon cycle by regulating the metabolism of sugar, the gluconeogenesis pathway, and the degradation and transport of transient starch.

Cell-free synthesis system-assisted pathway bottleneck diagnosis and engineering in Bacillus subtilis.

Metabolic engineering is a key technology for cell factories construction by rewiring cellular resources to achieve efficient production of target chemicals. However, the existence of bottlenecks in synthetic pathway can seriously affect production efficiency, which is also one of the core issues for metabolic engineers to solve. Therefore, developing an approach for diagnosing potential metabolic bottlenecks in a faster and simpler manner is of great significance to accelerate cell factories construction. The cell-free reaction system based on cell lysates can transfer metabolic reactions from in vivo to in vitro, providing a flexible access to directly change protein and metabolite variables, thus provides a potential solution for rapid identification of bottlenecks. Here, bottleneck diagnosis of the N-acetylneuraminic acid (NeuAc) biosynthesis pathway in industrially important chassis microorganism Bacillus subtilis was performed using cell-free synthesis system. Specifically, a highly efficient B. subtilis cell-free system for NeuAc de novo synthesis was firstly constructed, which had a 305-fold NeuAc synthesis rate than that in vivo and enabled fast pathway dynamics analysis. Next, through the addition of all potential key intermediates in combination with substrate glucose respectively, it was found that insufficient phosphoenolpyruvate supply was one of the NeuAc pathway bottlenecks. Rational in vivo metabolic engineering of NeuAc-producing B. subtilis was further performed to eliminate the bottleneck. By down-regulating the expression level of pyruvate kinase throughout the growth phase or only in the stationary phase using inhibitory N-terminal coding sequences (NCSs) and growth-dependent regulatory NCSs respectively, the maximal NeuAc titer increased 2.0-fold. Our study provides a rapid method for bottleneck diagnosis, which may help to accelerate the cycle of design, build, test and learn cycle for metabolic engineering.

Anterolateral muscle sparing approach total hip arthroplasty: an anatomic and clinical study.

BACKGROUND: Many kinds of approaches have been used for minimally invasive surgery of total hip arthroplasty (MIS-THA). However, until now when considering the balance of efficacy and associated surgical injury there is no approach widely accepted for MIS-THA. In this study, a modified anterolateral muscle sparing approach was developed to optimize MIS-THA. METHODS: Twenty adult cadaver specimens (40 hips) were used for anatomic research. The distance from anterior origin of the gluteus medius on the iliac crest to the anterior superior iliac spine was measured; the course of the superior gluteal nerve and the distances from the nerve to the regional anatomic landmarks were recorded. Simulated surgeries were performed in three fresh cadaver specimens to evaluate the soft tissues injury around incisions. From October 2004 to June 2006, 57 patients (57 hips) were treated with anterolateral muscle sparing minimally invasive total hip arthroplasty, of which 17 were femoral neck fractures, 9 osteoarthritis, 16 developmental dysplasia of hip (DDH) and 15 avascular necrosis (AVN). All the operations were performed by the same senior surgeon. Operation time, blood loss and drainage volume were recorded and the correlation between the local complications and the native anatomical characteristics was especially noted. All cases were followed for at least 12 months. RESULTS: The distance from the anterior origin of the gluteus medius to anterior superior iliac spine along the iliac crest was (61+/-4) mm (range, 55-68 mm), and the distance from inferior branch of the superior gluteal nerve to the anterior tubercle of the greater trochanter was (74+/-6) mm (range, 60-88 mm). In simulated surgeries, excessive distraction of tissue was found to be the main cause of the anterior border injury of the gluteus medius muscle. Of the 57 patients treated with anterolateral muscle sparing MIS-THA, the average incision length was 9 cm (range 7.5-13 cm). Blood transfusions were performed in 11 patients. During the operations, anterior border injury in deep layers of the gluteus medius was found in 9 patients. Posteromedial perforation of the prosthesis stem on the femoral side was found in 2 patients, which were revised immediately. No positive Trenderlenburg sign was found during the 12 months of follow-up. CONCLUSIONS: The incision of the anterolateral muscle sparing approach should be directed from the anterior tubercle of the greater trochanter toward 6 cm posterior to the anterior superior iliac spine. The proximal part of the incision should be within 6 cm from the anterior tubercle of the greater trochanter, and it is safe to be extended distally. The anterolateral muscle sparing approach is a minimally invasive approach for total hip arthroplasty, through which the surgeon can operate on the acetabulum and femoral sides in a single incision without muscle detachment, and fluoroscopy assistance is not needed. The surgeon should pay more attention to protecting the gluteus medius from injury by distraction before femoral neck cutting and during the preparation of the femoral side.