Periodic static compression of micro-strain pattern regulates endochondral bone formation.

Introduction: Developmental engineering based on endochondral ossification has been proposed as a potential strategy for repairing of critical bone defects. Bone development is driven by growth plate-mediated endochondral ossification. Under physiological conditions, growth plate chondrocytes undergo compressive forces characterized by micro-mechanics, but the regulatory effect of micro-mechanical loading on endochondral bone formation has not been investigated. Methods: In this study, a periodic static compression (PSC) model characterized by micro-strain (with 0.5% strain) was designed to clarify the effects of biochemical/mechanical cues on endochondral bone formation. Hydrogel scaffolds loaded with bone marrow mesenchymal stem cells (BMSCs) were incubated in proliferation medium or chondrogenic medium, and PSC was performed continuously for 14 or 28 days. Subsequently, the scaffold pretreated for 28 days was implanted into rat femoral muscle pouches and femoral condylar defect sites. The chondrogenesis and bone defect repair were evaluated 4 or 10 weeks post-operation. Results: The results showed that PSC stimulation for 14 days significantly increased the number of COL II positive cells in proliferation medium. However, the chondrogenic efficiency of BMSCs was significantly improved in chondrogenic medium, with or without PSC application. The induced chondrocytes (ichondrocytes) spontaneously underwent hypertrophy and maturation, but long-term mechanical stimulation (loading for 28 days) significantly inhibited hypertrophy and mineralization in ichondrocytes. In the heterotopic ossification model, no chondrocytes were found and no significant difference in terms of mineral deposition in each group; However, 4 weeks after implantation into the femoral defect site, all scaffolds that were subjected to biochemical/mechanical cues, either solely or synergistically, showed typical chondrocytes and endochondral bone formation. In addition, simultaneous biochemical induction/mechanical loading significantly accelerated the bone regeneration. Discussion: Our findings suggest that microstrain mechanics, biochemical cues, and in vivo microenvironment synergistically regulate the differentiation fate of BMSCs. Meanwhile, this study shows the potential of micro-strain mechanics in the treatment of critical bone defects.

Facile synthesis of a rod-like Ni/TiO2/C nanocomposite for enhanced electromagnetic wave absorption.

In this study, we utilized a simple calcination method to prepare a Ni/TiO2/C composite, which was synchronously grown from magnetic, semiconductor, and conductive materials. XRD, SEM, Raman, and XPS characterization methods were used to analyze the crystal structure, graphitization degree, morphology size, and valence state of Ni/TiO2/C, and its electromagnetic wave absorption performance was tested. It was revealed that rod-like Ni/TiO2/C had good electromagnetic wave absorption performance at a thickness of 1-5.5 mm; in particular, its reflectance reached -40 dB at 3.5 mm and its absorption bandwidth (reflectivity < -10 dB) reached 4.4 GHz (6.0-10.4 GHz) at a thickness of 4.0 mm. It was thus revealed that its electromagnetic wave absorption rate and absorption bandwidth can be regulated by its thickness. Compared with Ni/TiO2, it was proven that the conductive materials (carbon), magnetic materials (Ni), and semiconductor materials (TiO2) in the rod-like Ni/TiO2/C composite can synergistically absorb electromagnetic wave energy through dielectric and magnetic losses.

Forkhead box O proteins: steering the course of stem cell fate.

Stem cells are pivotal players in the intricate dance of embryonic development, tissue maintenance, and regeneration. Their behavior is delicately balanced between maintaining their pluripotency and differentiating as needed. Disruptions in this balance can lead to a spectrum of diseases, underscoring the importance of unraveling the complex molecular mechanisms that govern stem cell fate. Forkhead box O (FOXO) proteins, a family of transcription factors, are at the heart of this intricate regulation, influencing a myriad of cellular processes such as survival, metabolism, and DNA repair. Their multifaceted role in steering the destiny of stem cells is evident, as they wield influence over self-renewal, quiescence, and lineage-specific differentiation in both embryonic and adult stem cells. This review delves into the structural and regulatory intricacies of FOXO transcription factors, shedding light on their pivotal roles in shaping the fate of stem cells. By providing insights into the specific functions of FOXO in determining stem cell fate, this review aims to pave the way for targeted interventions that could modulate stem cell behavior and potentially revolutionize the treatment and prevention of diseases.

Nano-Bio Interactions: Biofilm-Targeted Antibacterial Nanomaterials.

Biofilm is a spatially organized community formed by the accumulation of both microorganisms and their secretions, leading to persistent and chronic infections because of high resistance toward conventional antibiotics. In view of the tunable physicochemical properties and the related unique biological behavior (e.g., size-, shape-, and surface charge-dependent penetration, protein corona endowed targeting, catalytic- and electronic-related oxidative stress, optical- and magnetic-associated hyperthermia, etc.), nanomaterials-based therapeutics are widely used for the treatment of biofilm-associated infections. In this review, the biological characteristics of biofilm are introduced. And the nanomaterials-based antibacterial strategies are further discussed via biofilm targeting, including preventing biofilm formation, enhancing biofilm penetration, disrupting the mature biofilm, and acting as drug delivery systems. In which, the interactions between biofilm and nanomaterials include mechanical disruption, electron transfer, enzymatic degradation, oxidative stress, and hyperthermia. Additionally, the current advances of nanomaterials for antibacterial nanomaterials by biofilm targeting are summarized. This review aims to present a complete vision of antibacterial nanomaterials-biofilm (nano-bio) interactions, paving the way for the future development and clinical translation of effective antibacterial nanomedicines.

High-sensitivity humidity and temperature sensor by cascading a polyimide coated long period fiber grating and a polydimethylsiloxane wrapped Mach-Zehnder interferometer.

Two different structures, long period fiber grating (LPFG) and a Mach-Zehnder interferometer (MZI), were cascaded to fabricate a sensor for sensing humidity and temperature simultaneously. Due to the humidity sensitive characteristic of polyimide (PI) and the temperature sensitive characteristic of polydimethylsiloxane (PDMS), the LPFG was coated with PI and the MZI was wrapped in PDMS to improve the humidity and temperature sensitivities, respectively. Humidity and temperature experiments and the stability and repeatability of the proposed sensors were performed. The sensor shows humidity and temperature sensitivities of ∼164 pm/%RH and 183 pm/°C in the humidity and temperature increasing experiments, respectively. Combining increasing, decreasing, and repeatable experiments of temperature and humidity, the proposed sensor shows stable performance in humidity sensitivity of ∼159 pm/%RH and temperature sensitivity of ∼175 pm/°C, with good linearity of ∼0.994. The structure of the proposed sensor has the advantages of low implementation cost, easy fabrication, and good stability.

Highly sensitive magnetic field sensors based on Fe2O3 nanorods grown on the surface of a tapered few mode fiber.

A magnetic field (MF) sensor with a stable structure and high sensitivity has been proposed and experimentally verified. We used the water bath method to produce a layer of Fe2O3 nanorods on a tapered few mode fiber (FMF) surface to form a Mach-Zehnder interferometer (MZI). The experiment found that the nanostructure produced on the surface of FMF were particularly stable and firm. Under the action of an external MF, the magnetic permeability of a Fe2O3 nanorod will change, leading to a change in its refractive index, resulting in a linear shift in the resonance wavelength of MZI. The experimental results showed that the MF sensitivity of MZI reached -0.5348 nm/mT in 10 mT∼80 mT. In addition, MZI has a certain sensitivity to environmental humidity and temperature. A long-period fiber grating and a fiber Bragg grating are cascaded with MZI to achieve a simultaneous measurement of three quantities and eliminate their cross-sensitivity.

The treatment of tuberculosis in the upper thoracic spine using the small incision technique through the third rib.

Background: The complex anatomical structure of the upper thoracic spine makes it challenging to achieve surgical exposure, resulting in significant surgical risks and difficulties. Posterior surgery alone fails to adequately address and reconstruct upper thoracic lesions due to limited exposure. While the anterior approach offers advantages in fully exposing the anterior thoracic lesions, the surgical procedure itself is highly intricate. Although there exist various anterior approaches for the upper thoracic spine, the incidence of upper thoracic spine lesions is relatively low. Consequently, there are limited reports on the treatment and reconstruction of upper thoracic spine lesions using the third rib small incision approach in the context of upper thoracic tuberculosis. Methods: We collected data from four patients with upper thoracic tuberculosis who were admitted to our department between July 2017 and November 2022. The treatment for upper thoracic tuberculosis involved utilizing the third rib small incision approach, which included two cases of thoracic 3-4 vertebral tuberculosis, one case of thoracic 4 vertebral tuberculosis, and one case of thoracic 5 vertebral tuberculosis. Among the patients, three were positioned in the left lateral position, while one was positioned in the right lateral position. Prior to admission, all four patients received a two-week course of oral medication, consisting of isoniazid, rifampicin, pyrazinamide, and ethambutol. After the surgical procedure, they continued receiving anti-tuberculosis treatment for a duration of 12 months. Results: The average duration of the surgical procedure was 150 min, with an average blood loss of 500 ml. One patient exhibited symptoms of brachial plexus injury, which gradually improved after careful observation. All patients experienced primary wound healing, and no complications such as pulmonary infection, respiratory failure, or other adverse events were observed. Additionally, one patient showed elevated transaminase levels, leading to a modification in the anti-tuberculosis drug regimen from quadruple therapy to triple therapy. Conclusion: The treatment of upper thoracic tuberculosis through the third rib small incision technique is a very good surgical approach, which has the advantages of safety and effectiveness.

TATA-box-binding protein promotes hepatocellular carcinoma metastasis through epithelial-mesenchymal transition.

BACKGROUND: HCC characterizes malignant metastasis with high incidence and recurrence. Thus, it is pivotal to discover the mechanisms of HCC metastasis. TATA-box-binding protein (TBP), a general transcriptional factor (TF), couples with activators and chromatin remodelers to sustain the transcriptional activity of target genes. Here, we investigate the key role of TBP in HCC metastasis. METHODS: TBP expression was measured by PCR, western blot, and immunohistochemistry. RNA-sequencing was performed to identify downstream proteins. Functional assays of TBP and downstream targets were identified in HCC cell lines and xenograft models. Luciferase reporter and chromatin immunoprecipitation assays were used to demonstrate the mechanism mediated by TBP. RESULTS: HCC patients showed high expression of TBP, which correlated with poor prognosis. Upregulation of TBP increased HCC metastasis in vivo and in vitro, and muscleblind-like-3 (MBNL3) was the effective factor of TBP, positively related to TBP expression. Mechanically, TBP transactivated and enhanced MBNL3 expression to stimulate exon inclusion of lncRNA-paxillin (PXN)-alternative splicing (AS1) and, thus, activated epithelial-mesenchymal transition for HCC progression through upregulation of PXN. CONCLUSIONS: Our data revealed that TBP upregulation is an HCC enhancer mechanism that increases PXN expression to drive epithelial-mesenchymal transition.

Redox Dysregulation in the Tumor Microenvironment Contributes to Cancer Metastasis.

Significance: Redox dysregulation under pathological conditions results in excessive reactive oxygen species (ROS) accumulation, leading to oxidative stress and cellular oxidative damage. ROS function as a double-edged sword to modulate various types of cancer development and survival. Recent Advances: Emerging evidence has underlined that ROS impact the behavior of both cancer cells and tumor-associated stromal cells in the tumor microenvironment (TME), and these cells have developed complex systems to adapt to high ROS environments during cancer progression. Critical Issues: In this review, we integrated current progress regarding the impact of ROS on cancer cells and tumor-associated stromal cells in the TME and summarized how ROS production influences cancer cell behaviors. Then, we summarized the distinct effects of ROS during different stages of tumor metastasis. Finally, we discussed potential therapeutic strategies for modulating ROS for the treatment of cancer metastasis. Future Directions: Targeting the ROS regulation during cancer metastasis will provide important insights into the design of effective single or combinatorial cancer therapeutic strategies. Well-designed preclinical studies and clinical trials are urgently needed to understand the complex regulatory systems of ROS in the TME. Antioxid. Redox Signal. 39, 472-490.

Uniparental parthenogenetic embryonic stem cell derivatives adaptable for bone and cartilage regeneration.

Cells with the desired phenotype and number are critical for regenerative medicine and tissue engineering. Uniparental parthenogenetic embryonic stem cells (pESCs) share fundamental properties with embryonic stem cells. This study aims to determine the viability of pESC-based tissue engineering for bone and cartilage reconstruction. The mouse pESCs were cultured in suspension to form embryoid bodies. An adherent cultivation approach was employed to obtain parthenogenetic embryonic mesenchymal stem cells (pMSCs) from the embryoid bodies. Then, the pMSCs were cultured in conditional media to differentiate into osteogenic and chondrogenic lineages. The pESC-derived osteoblasts and chondroblasts were seeded into coral and sodium alginate scaffolds, respectively. The cell-seeded scaffolds were implanted into dorsal subcutaneous pockets of nude mice to evaluate ectopic reconstruction of bone and cartilage. We demonstrated that pESCs display the capacity to differentiate into all three germ layers. The generated pMSCs were able to differentiate into osteogenic and chondrogenic lineages, which survived well after seeding into coral and alginate acid scaffolds. Six weeks after cell-scaffold implantation, gross inspection and histological examination revealed that ectopic bone and cartilage tissues had successfully regenerated in the specimen. According to the findings of this study, pESC derivatives have a high potential for bone and cartilage regeneration.

Impact of GTF2H1 and RAD54L2 polymorphisms on the risk of lung cancer in the Chinese Han population.

BACKGROUND: Repair pathway genes play an important role in the development of lung cancer. The study aimed to assess the correlation between single nucleotide polymorphisms (SNPs) in DNA repair gene (GTF2H1 and RAD54L2) and the risk of lung cancer. METHODS: Five SNPs in GTF2H1 and four SNPs in RAD54L2 in 506 patients with lung cancer and 510 age-and gender-matched healthy controls were genotyped via the Agena MassARRAY platform. The influence of GTF2H1 and RAD54L2 polymorphisms on lung cancer susceptibility was assessed using logistic regression analysis by calculating odds ratios (ORs) and their corresponding 95% confidence intervals (CIs). RESULTS: RAD54L2 rs9864693 GC genotype increased the risk of lung cancer (OR = 1.33, 95%CI: 1.01-1.77, p = 0.045). Stratified analysis found that associations of RAD54L2 rs11720298, RAD54L2 rs4687592, RAD54L2 rs9864693 and GTF2H1 rs4150667 with lung cancer risk were found in subjects aged ≤ 59 years. Precisely, a protective effect of RAD54L2 rs11720298 on the occurrence of lung cancer was observed in non-smokers and drinkers. GTF2H1 rs4150667 was associated with a decreased risk of lung cancer in subjects with BMI ≤ 24 kg/m2. RAD54L2 rs4687592 was associated with an increased risk of lung cancer in drinkers. In addition, GTF2H1 rs3802967 was associated with a reduced risk of lung squamous cell carcinoma. CONCLUSION: Our study first revealed that RAD54L2 rs9864693 was associated with an increased risk of lung cancer in the Chinese Han population. This study may increase the understanding of the effect of RAD54L2 and GTF2H1 polymorphisms on lung cancer occurrence.

Palladium-catalyzed oxidative Heck reaction of non-activated alkenes directed by fluorinated alcohol.

A novel, Pd-catalyzed oxidative Heck reaction of non-activated alkenes synergistically directed by bifunctional groups has been developed firstly by using O2 as a green oxidant, yielding the oxidative Heck products with excellent yields in a regio- and stereoselective manner. This bifunctional synergistic activation mechanism was demonstrated by experimental analysis and detailed computational studies, wherein the hydroxyl group directs the migratory insertion of the alkenes and the trifluoromethyl group facilitates the subsequent ß-H elimination and reductive elimination. Moreover, a pesticidal active compound was synthesized using the bifunctional synergistically directed C-H arylation as the key step, which demonstrated its synthetic utility.

The Stimulation of Macrophages by Systematical Administration of GM-CSF Can Accelerate Adult Wound Healing Process.

Skin wound repair remains a major challenge in clinical care, and various strategies have been employed to improve the repair process. Recently, it has been reported that macrophages are important for the regeneration of various tissues and organs. However, their influence on wound repair is unclear. Here, we aimed to explore whether macrophages would participate in the wound healing process and to explore new possibilities of treatment for skin defects. We firstly created a mouse full-thickness skin defect model to observe the distribution of macrophages in the regenerating tissue and then detected the influence of macrophages on skin defect repair in both macrophage-depletion and macrophage-mobilization models. We found that the number of macrophages increased significantly after skin defect and persisted during the process of wound repair. The regeneration process was significantly prolonged in macrophage-depleted animals. RT-qPCR and ELISA assays further demonstrated that the expression of growth factors was perturbed in the regenerating tissue. The activation of macrophages by granulocyte-macrophage colony-stimulating factor (GM-CSF) injection could significantly improve wound healing, accompanied with an upregulation of the expression of various growth factors. In conclusion, the current study demonstrated that macrophages are critical for skin regeneration and that GM-CSF exhibited therapeutic potential for wound healing.

Novel Fluorescence Probe toward Cu2+ Based on Fluorescein Derivatives and Its Bioimaging in Cells.

Copper is an important trace element that plays a crucial role in various physiological and biochemical processes in the body. The level of copper content is significantly related to many diseases, so it is very important to establish effective and sensitive methods for copper detection in vitro and vivo. Copper-selective probes have attracted considerable interest in environmental testing and life-process research, but fewer investigations have focused on the luminescence mechanism and bioimaging for Cu2+ detection. In the current study, a novel fluorescein-based A5 fluorescence probe is synthesized and characterized, and the bioimaging performance of the probe is also tested. We observed that the A5 displayed extraordinary selectivity and sensitivity properties to Cu2+ in contrast to other cations in solution. The reaction between A5 and Cu2+ could accelerate the ring-opening process, resulting in a new band at 525 nm during a larger pH range. A good linearity between the fluorescence intensity and concentrations of Cu2+, ranging from 0.1 to 1.5 equivalent, was observed, and the limit detection of A5 to Cu2+ was 0.11 µM. In addition, the Job's plot and mass spectrum showed that A5 complexed Cu2+ in a 1:1 manner. The apparent color change in the A5-Cu2+ complex under ultraviolet light at low molar concentrations revealed that A5 is a suitable probe for the detection of Cu2+. The biological test results show that the A5 probe has good biocompatibility and can be used for the cell imaging of Cu2+.

Long noncoding RNA LINC00239 inhibits ferroptosis in colorectal cancer by binding to Keap1 to stabilize Nrf2.

Ferroptosis, a novel regulated cell death induced by iron-dependent lipid peroxidation, plays an important role in tumor development and drug resistance. Long noncoding RNAs (lncRNAs) are associated with various types of cancer. However, the precise roles of many lncRNAs in tumorigenesis remain elusive. Here we explored the transcriptomic profiles of lncRNAs in primary CRC tissues and corresponding paired adjacent non-tumor tissues by RNA-seq and found that LINC00239 was significantly overexpressed in colorectal cancer tissues. Abnormally high expression of LINC00239 predicts poorer survival and prognosis in colorectal cancer patients. Concurrently, we elucidated the role of LINC00239 as a tumor-promoting factor in CRC through in vitro functional studies and in vivo tumor xenograft models. Importantly, overexpression of LINC00239 decreased the anti-tumor activity of erastin and RSL3 by inhibiting ferroptosis. Collectively, these data suggest that LINC00239 plays a novel and indispensable role in ferroptosis by nucleotides 1-315 of LINC00239 to interact with the Kelch domain (Nrf2-binding site) of Keap1, inhibiting Nrf2 ubiquitination and increasing Nrf2 protein stability. Considering the recurrence and chemoresistance constitute the leading cause of death in colorectal cancer (CRC), ferroptosis induction may be a promising therapeutic strategy for CRC patients with low LINC00239 expression.

A Highly Sensitive and Selective Fluorescein-Based Cu2+ Probe and Its Bioimaging in Cell.

Copper is a vital trace metal in human body, which plays the significant roles in amounts of physiological and pathological processes. The application of copper-selective probe has attracted great interests from environmental tests to life process research, yet a few of sensitive Cu2+ tests based on on-site analysis have been reported. In this paper, a novel fluorescein-based fluorescent probe N4 was designed, synthesized, and characterized, which exhibited high selectivity and sensitivity to Cu2+ comparing with other metal ions in ethanol-water (1/1, v/v) solution. The probe N4 bonded with Cu2+ to facilitate the ring-opening, and an obvious new band at 525 nm in the fluorescence spectroscopy appeared, which could be used for naked-eye detection of Cu2+ within a broad pH range of 6-9. Meanwhile, a good linearity between the fluorescence intensity and the concentrations of Cu2+ ranged 0.1-1.5 eq. was observed, and the limit of detection of N4 to Cu2+ was calculated to be as low as 1.20 µm. In addition, the interaction mode between N4 and Cu2+ was found to be 1:1 by the Job's plot and mass experiment. Biological experiments showed that the probe N4 exhibited low biological toxicity and could be applied for Cu2+ imaging in living cells. The significant color shift associated with the production of the N4-Cu2+ complex at low micromolar concentrations under UV light endows N4 with a promising probe for field testing of trace Cu2+ ions.

Novel tissue-engineered skin equivalent from recombinant human collagen hydrogel and fibroblasts facilitated full-thickness skin defect repair in a mouse model.

Tissue-engineered skin equivalent (TESE) is an optimized alternative for the treatment of skin defects. Designing and fabricating biomaterials with desired properties to load cells is critical for the approach. In this study, we aim to develop a novel TESE with recombinant human collagen (rHC) hydrogel and fibroblasts to improve full-thickness skin defect repair. First, the bioactive effect of rHC on fibroblast proliferation, migration and phenotype was assayed. The results showed that rHC had good biocompatibility and could stimulate fibroblasts migration and secrete various growth factors. Then, rHC was cross-linked with transglutaminase (TG) to prepare rHC hydrogel. Rheometer tests indicated that 10% rHC/TG hydrogel could reach a oscillate stress of 251 Pa and remained stable. Fibroblasts were seeded into rHC/TG hydrogel to prepare TESE. Confocal microscope and scanning electronic microscope observation showed that seeded fibroblasts survived well in the hydrogel. Finally, the therapeutic effect of the newly prepared TESE was tested in a mouse full-thickness skin defect model. The results demonstrated that TESE could significantly improve skin defect repair in vivo. Conclusively, TESE prepared from rHC and fibroblasts in this study exhibits great potential for clinical application in the future.

PI3K Plays an Essential Role in Planarian Regeneration and Tissue Maintenance.

Phosphatidylinositol 3-kinase (PI3K) signaling plays a central role in various biological processes, and its abnormality leads to a broad spectrum of human diseases, such as cancer, fibrosis, and immunological disorders. However, the mechanisms by which PI3K signaling regulates the behavior of stem cells during regeneration are poorly understood. Planarian flatworms possess abundant adult stem cells (called neoblasts) allowing them to develop remarkable regenerative capabilities, thus the animals represent an ideal model for studying stem cells and regenerative medicine in vivo. In this study, the spatiotemporal expression pattern of Djpi3k, a PI3K ortholog in the planarian Dugesia japonica, was investigated and suggests its potential role in wound response and tissue regeneration. A loss-of-function study was conducted using small molecules and RNA interference technique, providing evidence that PI3K signaling is required for blastema regrowth and cilia maintenance during planarian regeneration and homeostasis. Interestingly, the mitotic and apoptotic responses to amputation are substantially abated in PI3K inhibitor-treated regenerating animals, while knockdown of Djpi3k alleviates the mitotic response and postpones the peak of apoptotic cell death, which may contribute to the varying degrees of regenerative defects induced by the pharmacological and genetic approaches. These observations reveal novel roles for PI3K signaling in the regulation of the cellular responses to amputation during planarian regeneration and provide insights for investigating the disease-related genes in the regeneration-competent organism in vivo.

Protein Core Fucosylation Regulates Planarian Head Regeneration via Neoblast Proliferation.

Protein glycosylation is an important posttranslational modification that plays a crucial role in cellular function. However, its biological roles in tissue regeneration remain interesting and primarily ambiguous. In this study, we profiled protein glycosylation during head regeneration in planarian Dugesia japonica using a lectin microarray. We found that 6 kinds of lectins showed increased signals and 16 kinds showed decreased signals. Interestingly, we found that protein core fucosylation, manifested by Lens culinaris agglutinin (LCA) staining, was significantly upregulated during planarian head regeneration. Lectin histochemistry indicated that the LCA signal was intensified within the wound and blastemal areas. Furthermore, we found that treatment with a fucosylation inhibitor, 2F-peracetyl-fucose, significantly retarded planarian head regeneration, while supplement with L-fucose could improve DjFut8 expression and stimulate planarian head regeneration. In addition, 53 glycoproteins that bound to LCA were selectively isolated by LCA-magnetic particle conjugates and identified by LC-MS/MS, including the neoblast markers DjpiwiA, DjpiwiB, DjvlgA, and DjvlgB. Overall, our study provides direct evidence for the involvement of protein core fucosylation in planarian regeneration.

Characterization and Transcriptome Analysis of a Long-Chain n-Alkane-Degrading Strain Acinetobacter pittii SW-1.

Strain sw-1, isolated from 7619-m seawater of the Mariana Trench, was identified as Acinetobacter pittii by 16S rRNA gene and whole-genome sequencing. A. pittii sw-1 was able to efficiently utilize long-chain n-alkanes (C18-C36), but not short- and medium-chain n-alkanes (C8-C16). The degradation rate of C20 was 91.25%, followed by C18, C22, C24, C32, and C36 with the degradation rates of 89.30%, 84.03%, 80.29%, 30.29%, and 13.37%, respectively. To investigate the degradation mechanisms of n-alkanes for this strain, the genome and the transcriptome analyses were performed. Four key alkane hydroxylase genes (alkB, almA, ladA1, and ladA2) were identified in the genome. Transcriptomes of strain sw-1 grown in C20 or CH3COONa (NaAc) as the sole carbon source were compared. The transcriptional levels of alkB and almA, respectively, increased 78.28- and 3.51-fold in C20 compared with NaAc, while ladA1 and ladA2 did not show obvious change. The expression levels of other genes involved in the synthesis of unsaturated fatty acids, permeases, membrane proteins, and sulfur metabolism were also upregulated, and they might be involved in n-alkane uptake. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) confirmed that alkB expression was significantly induced by C20, C24, and C32, and almA induction extent by C24 and C32 was higher than that with C20. Furthermore, ladA2 expression was only induced by C32, and ladA1 expression was not induced by any of n-alkanes. In addition, A. pittii sw-1 could grow with 0%-3% NaCl or 8 out of 10 kinds of the tested heavy metals and degrade n-alkanes at 15 °C. Taken together, these results provide comprehensive insights into the degradation of long-chain n-alkanes by Acinetobacter isolated from the deep ocean environment.