Recent advances in discovery and biosynthesis of natural products from myxobacteria: an overview from 2017 to 2023.

Covering: 2017.01 to 2023.11Natural products biosynthesized by myxobacteria are appealing due to their sophisticated chemical skeletons, remarkable biological activities, and intriguing biosynthetic enzymology. This review aims to systematically summarize the advances in the discovery methods, new structures, and bioactivities of myxobacterial NPs reported in the period of 2017-2023. In addition, the peculiar biosynthetic pathways of several structural families are also highlighted.

Constructing a Myxobacterial Natural Product Database to Facilitate NMR-Based Metabolomics Bioprospecting of Myxobacteria.

Myxobacteria are fascinating prokaryotes featuring a potent capacity for producing a wealth of bioactive molecules with intricate chemical topology as well as intriguing enzymology, and thus it is critical to developing an efficient pipeline for bioprospecting. Herein, we construct the database MyxoDB, the first public compendium solely dedicated to myxobacteria, which enabled us to provide an overview of the structural diversity and taxonomic distribution of known myxobacterial natural products. Moreover, we demonstrated that the cutting-edge NMR-based metabolomics was effective to differentiate the biosynthetic priority of myxobacteria, whereby MyxoDB could greatly streamline the dereplication of multifarious known compounds and accordingly speed up the discovery of new compounds. This led to the rapid identification of a class of linear di-lipopeptides (archangimins) and a rare rearranged sterol (corasterol) that were endowed with unique chemical architectures and/or biosynthetic enzymology. We also showcased that NMR-based metabolomics, MyxoDB, and genomics can also work concertedly to accelerate the targeted discovery of a polyketidic compound pyxipyrrolone C. All in all, this study sets the stage for the discovery of many more novel natural products from underexplored myxobacterial resources.

Discovery and Biosynthesis of Glycosylated Cycloheximide from a Millipede-Associated Actinomycete.

Chemical redundancy of microbial natural products (NPs) underscores the importance to exploit new resources of microorganisms. Insect-associated microbes are prolific but largely underexplored sources of diverse NPs. Herein, we discovered the new compound α-l-rhamnosyl-actiphenol (1) from a millipede-associated Streptomyces sp. ML6, which is the first glycosylated cycloheximide-class natural product. Interestingly, bioinformatics analysis of the ML6 genome revealed that the biosynthesis of 1 involves a cooperation between two gene clusters (chx and rml) located distantly on the genome of ML6. We also carried out in vitro enzymatic glycosylation of cycloheximide using an exotic promiscuous glycosyltransferase BsGT-1, which resulted in the production of an additional cycloheximide glycoside cycloheximide 7-O-ß-d-glucoside (5). Although the antifungal and cytotoxic activities of the new compounds 1 and 5 were attenuated relative to those of cycloheximide, our work not only enriches the chemical repertoire of the cycloheximide family but also provides new insights into the structure-activity relationship optimization and ecological roles of cycloheximide.

[Correlation of sperm HDS with sperm DFI and morphology and its influence on in vitro fertilization in infertile males].

OBJECTIVE: To invest the correlation of sperm high DNA stainability (HDS) with sperm DNA fragmentation index (DFI) and sperm abnormalities and its influence on in vitro fertilization (IVF) in male infertility patients, and assess the clinical value of HDS. METHODS: Using flow cytometry-assisted sperm chromatin structure assay (SCSA), we examined sperm HDS and sperm DFI in 322 male infertility patients undergoing IVF due to female fallopian tube factors only. Based on sperm HDS, we divided the patients into five groups and compared the semen routine parameters, percentage of morphologically abnormal sperm (MAS), sperm DFI, rates of fertilization, cleavage and high-quality embryos, and pregnancy outcomes among different HDS groups. RESULTS: Among the 322 male infertility patients, 119 (36.96%) were found with a sperm HDS of 0 － <5%, 117 (36.34%) of 5% － <10%, 50 (15.53%) of 10% － <15%, 23 (7.14%) of 15% － <20%, and 13 (4.03%) of ≥20%. Sperm concentration, motility and progressive motility were decreased with the increase of sperm HDS, but with no statistically significant difference (P > 0.05), so were the rates of fertilization, high-quality embryos and pregnancy (P > 0.05). Sperm DFI and sperm abnormality were correlated positively with sperm HDS (r = 0.236, r = 0.203). The rate of early abortion was remarkably increased in those with sperm HDS greater than 10%. CONCLUSION: Sperm HDS may be a risk indicator of sperm DFI and sperm abnormality, and can be used as a predictive indicator of early abortion in IVF.

Computed tomography-guided radiofrequency ablation of cervical intervertebral discs for the treatment of refractory cervicogenic headache: A retrospective chart review.

OBJECTIVE: To evaluate the feasibility and efficacy of computed tomography (CT)-guided radiofrequency ablation (RFA) of cervical intervertebral discs for the treatment of discogenic cervicogenic headache (CEH). BACKGROUND: Some patients with CEH experience no obvious therapeutic effect after conventional therapy, particularly patients with refractory CEH originating from abnormal cervical intervertebral discs. Treatment for this type of CEH remains poorly characterized. METHODS: Using a single intervention arm, pretest/posttest design, we retrospectively analyzed the data of patients who underwent CT-guided RFA of cervical intervertebral discs for CEH at the Pain Medicine Center of Zhejiang Provincial People's Hospital from January 2017 to April 2021. If conservative treatment failed in patients with discogenic CEH, we classified the patients as having refractory CEH and performed RFA of cervical intervertebral discs. We used a numeric rating scale (NRS) to assess pain intensity for 6 months. We also compared therapeutic outcome of patients with different characteristics. RESULTS: A total of 44 patients who underwent CT-guided RFA of cervical intervertebral discs were enrolled and 41 of them were analyzed in the present study. The preoperative median (25th, 75th) NRS score was 4 (4, 5), and it was significantly reduced to 1 (0, 4) 6 months after RFA (p < 0.001). The number of patients with ≥50% of their pain relieved after 6 months was 28 of 41 (68%). No serious treatment-related complications occurred in this study. Compared with single-level RFA, multi-level RFA shows greater effects on pain intensity reduction (p = 0.032) and pain relief rate (p = 0.047) of patients. CONCLUSION: In patients who have discogenic CEH, CT-guided RFA of the cervical intervertebral discs appears to be a promising treatment with no serious complications.

[Correlation of sperm DNA fragmentation index and high DNA stainability with teratospermia severity and the patient's age: A study of 1 393 infertile males].

OBJECTIVE: To investigate the correlation of the severity of teratospermia and the age of the patient with sperm DNA fragmentation index (DFI) and high DNA stainability (HDS) in male infertility patients. METHODS: We collected semen samples from 1 393 infertile males from July to December 2021. Based on the WHO Laboratory Manual for the Examination and Processing of Human Semen (5th Ed), we performed sperm morphology analysis, examined perm DFI and HDS by flow cytometry, and analyzed the impacts of the severity of teratospermia and the age of the patients on sperm DFI and HDS. RESULTS: Among the 1 393 male infertility patients, 124 (8.90%) were found with extremely severe, 214 (15.36%) with severe, 235 (16.87%) with moderate, 163 (11.70%) with mild teratospermia, and 657 (47.16%) with morphologically normal sperm (MNS), with statistically significant differences in sperm DFI and HDS among the five groups, and 822 (59.00%) were aged <35 years, 306 (21.97%) 35－<40 years, 223 (16.01%) 40－<45 years and 42 (3.02%) ≥45 years, with statistically significant differences in sperm DFI and HDS among different age groups (P < 0.05). Sperm DFI and HDS were correlated negatively with the percentage of MNS (P > 0.05), but positively with the age of the patients (P < 0.05). CONCLUSION: Increased severity of teratospermia and age of the patient can increase sperm DFI and HDS, and sperm nuclear chromatin integrity and maturity are important indicators of male fertility.

The characteristics and related factors of insomnia among postoperative patients with gastric cancer: a cross-sectional survey.

PURPOSE: This study aims to explore the characteristics and related factors of insomnia of patients after operation for gastric cancer. METHODS: A cross-sectional survey was carried out and finally 115 patients with insomnia after operation for gastric cancer were included. The general information, gastric cancer-related information, sleep quality, and other symptoms were investigated. RESULTS: ① The Pittsburgh sleep quality index score of most insomnia patients after gastric cancer surgery was 11-15 points, and the sleep quality rating was "poor". ② The sleep quality of patients with insomnia after surgery for gastric cancer is related to the number of chemotherapy cycles, fatigue, and depression. ③ The probability of reduced sleep quality with the number of chemotherapy cycles >6 is 3.640 times that of ≤6. The probability of reduced sleep quality during moderate to severe fatigue was 4.390 times that of patients with no or mild fatigue. CONCLUSION: Attention to related factors may be associated with improvement of sleep quality in patients with gastric cancer after surgery.

Chemical Logic Gates on Active Colloids.

Recent studies have shown that active colloidal motors using enzymatic reactions for propulsion hold special promise for applications in fields ranging from biology to material science. It will be desirable to have active colloids with capability of computation so that they can act autonomously to sense their surroundings and alter their own dynamics. It is shown how small chemical networks that make use of enzymatic chemical reactions on the colloid surface can be used to construct motor-based chemical logic gates. The basic features of coupled enzymatic reactions that are responsible for propulsion and underlie the construction and function of chemical gates are described using continuum theory and molecular simulation. Examples are given that show how colloids with specific chemical logic gates, can perform simple sensing tasks. Due to the diverse functions of different enzyme gates, operating alone or in circuits, the work presented here supports the suggestion that synthetic motors using such gates could be designed to operate in an autonomous way in order to complete complicated tasks.

L-Type Calcium Channel Modulates Low-Intensity Pulsed Ultrasound-Induced Excitation in Cultured Hippocampal Neurons.

As a noninvasive technique, ultrasound stimulation is known to modulate neuronal activity both in vitro and in vivo. The latest explanation of this phenomenon is that the acoustic wave can activate the ion channels and further impact the electrophysiological properties of targeted neurons. However, the underlying mechanism of low-intensity pulsed ultrasound (LIPUS)-induced neuro-modulation effects is still unclear. Here, we characterize the excitatory effects of LIPUS on spontaneous activity and the intracellular Ca2+ homeostasis in cultured hippocampal neurons. By whole-cell patch clamp recording, we found that 15 min of 1-MHz LIPUS boosts the frequency of both spontaneous action potentials and spontaneous excitatory synaptic currents (sEPSCs) and also increases the amplitude of sEPSCs in hippocampal neurons. This phenomenon lasts for > 10 min after LIPUS exposure. Together with Ca2+ imaging, we clarified that LIPUS increases the [Ca2+]cyto level by facilitating L-type Ca2+ channels (LTCCs). In addition, due to the [Ca2+]cyto elevation by LIPUS exposure, the Ca2+-dependent CaMKII-CREB pathway can be activated within 30 min to further regulate the gene transcription and protein expression. Our work suggests that LIPUS regulates neuronal activity in a Ca2+-dependent manner via LTCCs. This may also explain the multi-activation effects of LIPUS beyond neurons. LIPUS stimulation potentiates spontaneous neuronal activity by increasing Ca2+ influx.