Environmental and molecular regulation of diapause formation in a scyphozoan jellyfish.

Understanding the mechanisms underlying diapause formation is crucial for gaining insight into adaptive survival strategies across various species. In this study, we aimed to uncover the pivotal role of temperature and food availability in regulating diapausing podocyst formation in the jellyfish Aurelia coerulea. Furthermore, we explored the cellular and molecular basis of diapause formation using single-cell RNA sequencing. Our results showed cell-type-specific transcriptional landscapes during podocyst formation, which were underscored by the activation of specific transcription factors and signalling pathways. In addition, we found that the heat shock protein-coding genes HSC70 and HSP90a potentially act as hub genes that regulate podocyst formation. Finally, we mapped the single-cell atlas of diapausing podocysts and identified cell types involved in metabolism, environmental sensing, defence and development that may collectively contribute to the long-term survival and regulated excystment of diapausing podocysts. Taken together, the findings of this study provide novel insights into the molecular mechanisms that regulate diapause formation and contributes to a better understanding of adaptive survival strategies in a variety of ecological contexts.

Impact of summer hypoxia on macrobenthic communities in a semi-enclosed bay: A long-term observation in the North Yellow sea of China.

The O2 content of the global ocean has been declining progressively over the past decades, mainly because of human activities and global warming. Despite this situation, the responses of macrobenthos under hypoxic conditions remain poorly understood. In this study, we conducted a long-term observation (2015-2022) to investigate the intricate impact of summer hypoxia on macrobenthic communities in a semi-enclosed bay of the North Yellow Sea. Comparative analyses revealed higher macrobenthos abundance (1956.8 ± 1507.5 ind./m2 vs. 871.8 ± 636.9 ind./m2) and biomass (8.2 ± 4.1 g/m2 vs. 5.6 ± 3.2 g/m2) at hypoxic sites compared to normoxic sites during hypoxic years. Notably, polychaete species demonstrated remarkable adaptability, dominating hypoxic sites, and shaping community structure. The decline in biodiversity underscored the vulnerability and diminished resilience of macrobenthic communities to hypoxic stressors. Stable isotope analysis provided valuable insights into food web structures. The average trophic level of macrobenthos measured 2.84 ± 0.70 at hypoxic sites, contrasting with the higher value of 3.14 ± 0.74 observed at normoxic sites, indicating the absence of predators at high trophic levels under hypoxic conditions. Moreover, trophic interactions were significantly altered, resulting in a simplified and more vulnerable macrobenthic trophic structure. The findings underscored the importance of comprehensive research to understand the complex responses of macrobenthic communities to hypoxia, thereby informing future conservation efforts in impacted ecosystems.

Nonylphenol displays immunotoxicity by triggering hemocyte extracellular traps in Manila clam via ROS burst, ERK pathway and glycolysis.

Nonylphenol (NP), an endocrine disruptor, has been demonstrated to be a harmful environmental contaminant and toxic to organisms. In this study, to address concerns regarding the immunotoxicity of NP, we treated clam Ruditapes philippinarum hemocytes with NP in vitro and explored the underlying mechanisms of NP-induced extracellular traps (ETs). NP could induce the formation of hemocytes ETs in a dose-dependent manner. Transcriptomics analysis revealed changes of signaling pathway involved in immunity and energy metabolism in hemocytes after NP stimulation. In this process, both reactive oxygen species (ROS) and myeloperoxidase (MPO) were up-regulated. Moreover, mitogen-activated protein kinase (MAPK) signaling pathway was proved to be activated in the formation of NP-induced ETs, manifested as enhanced phosphorylation of extracellular signal-regulated kinase (ERK) but not p38 or c-Jun N-terminal kinase (JNK). In the presence of U0126, an ERK phosphorylation inhibitor, the NP-induced expression of NADPH oxidase enzyme (NOX) was significantly decreased, which further alleviated the ROS production and ultimately limited the release of ETs. NP exposure increased glucose uptake, along with enhanced activities of glycolysis-related enzymes such as hexokinase (HK) and pyruvate kinase (PK). After inhibiting glycolysis by the inhibitor 2-DG, the formation of NP-induced ETs was significantly suppressed. ERK could regulate mTOR signaling and the PI3K/AKT pathway, potentially directing ETs formation by orchestrating the glycolysis through the activation of key transcription factors c-Myc and HIF-1α. Collectively, the results preliminary confirm that the ERK-NOX-ROS axis and glycolysis are involved in NP-induced ETs formation, contributing to the cellular immunotoxicity in clam.

Intrinsic and extrinsic pathways of apoptosis induced by multiple antibiotics residues and ocean acidification in hemocytes of scallop Argopecten irradians irradians: An interactionist perspective.

The increasing prevalence of antibiotics in seawater across global coastal areas, coupled with the ocean acidification induced by climate change, present a multifaceted challenge to marine ecosystems, particularly impacting the key physiological processes of marine organisms. Apoptosis is a critical adaptive response essential for maintaining cellular homeostasis and defending against environmental threats. In this study, bay scallops Argopecten irradians irradians were exposed to multiple antibiotics (sulfamethoxazole, tetracycline, oxytetracycline, norfloxacin, and erythromycin, each at a concentration of 1 µg/L) combined with/without acidic seawater (pH 7.6) for 35 days. The single and interactive effects of the two stressors on apoptosis and the underlying mechanisms in hemocytes of A. irradians irradians were determined through flow cytometry analysis, comet assay, oxidative stress biomarkers analysis, and transcriptome analysis. Results showed that apoptosis could be triggered by either AM exposure or OA exposure, but through different pathways. Exposure to AM leads to mitochondrial dysfunction and oxidative damage, which in turn triggers apoptosis via a series of cellular events in both intrinsic and extrinsic pathways. Conversely, while OA exposure similarly induced apoptosis, its effects are comparatively subdued and are predominantly mediated through the intrinsic pathway. Additionally, the synergistic effects of AM and OA exposure induced pronounced mitochondrial dysfunction and oxidative damages in the hemocytes of A. irradians irradians. Despite the evident cellular distress and the potential initiation of apoptotic pathways, the actual execution of apoptosis appears to be restrained, which might be attributed to an energy deficit within the hemocytes. Our findings underscore the constrained tolerance capacity of A. irradians irradians when faced with multiple environmental stressors, and shed light on the ecotoxicity of antibiotic pollution in the ocean under prospective climate change scenarios.

Genome-wide characterization of regulator of chromosome condensation 1 (RCC1) gene family in Artemisia annua L. revealed a conservation evolutionary pattern.

BACKGROUND: Artemisia annua is the major source for artemisinin production. The artemisinin content in A. annua is affected by different types of light especially the UV light. UVR8, a member of RCC1 gene family was found to be the UV-B receptor in plants. The gene structures, evolutionary history and expression profile of UVR8 or RCC1 genes remain undiscovered in A. annua. RESULTS: Twenty-two RCC1 genes (AaRCC1) were identified in each haplotype genome of two diploid strains of A. annua, LQ-9 and HAN1. Varied gene structures and sequences among paralogs were observed. The divergence of most RCC1 genes occurred at 46.7 - 51 MYA which overlapped with species divergence of core Asteraceae during the Eocene, while no recent novel RCC1 members were found in A. annua genome. The number of RCC1 genes remained stable among eudicots and RCC1 genes underwent purifying selection. The expression profile of AaRCC1 is analogous to that of Arabidopsis thaliana (AtRCC1) when responding to environmental stress. CONCLUSIONS: This study provided a comprehensive characterization of the AaRCC1 gene family and suggested that RCC1 genes were conserved in gene number, structures, constitution of amino acids and expression profiles among eudicots.

Dynamics of Benthic Nitrate Reduction Pathways and Associated Microbial Communities Responding to the Development of Seasonal Deoxygenation in a Coastal Mariculture Zone.

Intensive mariculture activities result in eutrophication and enhance coastal deoxygenation. Deoxygenation profoundly influences nitrate reduction processes and further the fate of nitrogen (N) in coastal systems. Herein, 15N isotope labeling, real-time PCR, and high-throughput sequencing techniques were jointly used to investigate the participation and seasonal dynamics of sediment nitrate reduction pathways and the succession of functional microbial communities during the development of seasonal deoxygenation in a coastal aquaculture zone. Denitrification dominated benthic nitrate reduction (46.26-80.91%). Both denitrification and dissimilatory nitrate reduction to ammonium were significantly enhanced by summer deoxygenation (dissolved oxygen levels fell to 2.94 ± 0.28 mg L-1), while anammox remained unchanged. The abundance of the nitrous oxide reductase gene nosZ increased during deoxygenation. The community of the nosZ gene was sensitive to deoxygenation, with Azospirillum and Ruegeria accounting for the majority. Pelobacter was overwhelming in the nrfA gene (encoding dissimilatory nitrite reductase) community, which was less affected by deoxygenation. The variations of benthic nitrate reduction processes were driven by bottom water oxygen combined with temperature, chlorophyll a, and microbial gene abundances and community compositions. Our results implicated that seasonal oxygen-deficient zones could be substantial N sinks of coastal ecosystems and important for N balance. Effective management measures need to be developed to avoid further exacerbation of coastal deoxygenation and maintain the sustainable development of mariculture.

Bifidobacterium lactis Probio-M8 improves bone metabolism in patients with postmenopausal osteoporosis, possibly by modulating the gut microbiota.

PURPOSE: Postmenopausal osteoporosis (PMO) is usually managed by conventional drug treatment. However, prolonged use of these drugs cause side effects. Gut microbiota may be a potential target for treatment of PMO. This work was a three-month intervention trial aiming to evaluate the added effect of probiotics as adjunctive treatment for PMO. METHODS: Forty patients with PMO were randomized into probiotic (n = 20; received Bifidobacterium animalis subsp. lactis Probio-M8 [Probio-M8], calcium, calcitriol) and placebo (n = 20; received placebo material, calcium, calcitriol) groups. The bone mineral density of patients was measured at month 0 (0 M; baseline) and month 3 (3 M; after three-month intervention). Blood and fecal samples were collected 0 M and 3 M. Only 15 and 12 patients from Probio-M8 and placebo groups, respectively, provided complete fecal samples for gut microbiota analysis. RESULTS: No significant change was observed in the bone mineral density of patients at 3 M. Co-administering Probio-M8 improved the bone metabolism, reflected by an increased vitamin D3 level and decreased PTH and procalcitonin levels in serum at 3 M. Fecal metagenomic analysis revealed modest changes in the gut microbiome in both groups at 3 M. Interestingly, Probio-M8 co-administration affected the gut microbial interactive correlation network, particularly the short-chain fatty acid-producing bacteria. Probio-M8 co-administration significantly increased genes encoding some carbohydrate metabolism pathways (including ABC transporters, the phosphotransferase system, and fructose and mannose metabolism) and a choline-phosphate cytidylyltransferase. CONCLUSIONS: Co-administering Probio-M8 with conventional drugs/supplements was more efficacious than conventional drugs/supplements alone in managing PMO. Our study shed insights into the beneficial mechanism of probiotic adjunctive treatment. REGISTRATION NUMBER OF CLINICAL TRIAL: Chinese Clinical Trial Registry (identifier number: ChiCTR1800019268).

Promoting effect of raft-raised scallop culture on the formation of coastal hypoxia.

The coastal waters around the Yangma Island are an important mariculture area of raft-raised scallop and bottom-seeded sea cucumber in the North Yellow Sea, China. Large-scale hypoxia in the bottom water of this area has caused the death of a large number of sea cucumbers and heavy economic losses. To find out the formation mechanism of hypoxia, the data obtained in each August during 2015-2018 were analyzed. Compared with the non-hypoxic year (2018), the temperature, trophic index (TRIX) and dissolved organic carbon (DOC) in the bottom water were relatively higher, and the water column was stratified causing by continuous high air temperature and low wind speed meteorological conditions in the hypoxic years (2015-2017). These sites with the coexistence of thermocline and halocline, and the thickness of thermocline >2.5 m and its upper boundary >7.0 m deep, were prone to hypoxia. Spatially, the hypoxic place was highly consistent with the scallop cultivating places, and the DOC, TRIX, NH4+/NO3- and apparent oxygen utilization (AOU) at the culture sites were higher, indicating that organic matter and nutrients released by scallops may lead to local oxygen depletion. In addition, the bottom water of the culture sites had higher salinity, but lower turbidity and temperature, indicating that the slowed water exchange caused by scallop culture was a dynamic factor of hypoxia. All sites with AOU >4 mg/L at the bottom had hypoxia occurrence, even if there was no thermocline. In other words, stratification promoted the formation of hypoxia in coastal bottom water, but it was not indispensable. The raft-raised scallop culture could promote the formation of coastal hypoxia, which should arouse the attention for other coastal areas with intensive bivalve production.

In vitro study of deltamethrin-induced extracellular traps in hemocytes of Ruditapes philippinarum.

Deltamethrin (DLM), a broad-spectrum pesticide, has been proven to have toxic effects on aquatic organisms. Here, we detected the formation of extracellular traps (ETosis) formation in Manila clam (Ruditapes philippinarum) hemocytes stimulated by three concentrations of DLM (0.01, 0.1 and 1 µg/mL) in vitro, and explored the underlying mechanisms induced by this pesticide. Extracellular DNA structure observation and quantitative results indicated that DLM exposure could obviously induce hemocytes ETosis, especially under high concentration of DLM induction. Moreover, DLM increased the levels of myeloperoxidase (MPO) and reactive oxygen species (ROS) in a dose-dependent manner, and enhanced the mRNA expression of several ROS-related genes. DPI (NADPH oxidase inhibitor) and ABAH (MPO inhibitor) could substantially inhibit DLM-induced extracellular traps (ETs), suggesting that the induced ETs release was caused by the induction of the ROS burst and MPO production. In addition, three concentrations of DLM-induced ETs were also accompanied by mitochondrial dysfunction, such as increasing the production of mitochondrial ROS, leading to a decrease in mitochondrial membrane potential (MMP) and activation of mitochondrial permeability transition pore (MPTP). Taken together, these results will shed new light on the immunotoxicity of DLM in clams and perhaps lays the foundation for health assessment in bivalves.

Effects of the potential probiotic Bacillus subtilis D1-2 on growth, digestion, immunity and intestinal flora in juvenile sea cucumber, Apostichopus japonicus.

In the present study, a potential probiotic Bacillus subtilis D1-2 with antibacterial activity was isolated from the gut of Apostichopus japonicus. The purpose of this experiment was to assess the effect of B. subtilis D1-2 at different concentrations (C: 0 CFU/g, BL: 105 CFU/g, BM: 107 CFU/g and BH: 109 CFU/g) on the growth performance, digestive enzyme activity, immune ability and intestinal flora of A. japonicus. After the 56-day feeding trial, the final body weight and weight gain rate of juvenile sea cucumber A. japonicus fed B. subtilis D1-2 were significantly increased, especially in the BM group. Additionally, the lipase activity of the intestine was significantly increased in the BM and BH groups. Enhanced immunity was also found in sea cucumbers supplemented with B. subtilis D1-2. Alpha diversity indices showed that the B. subtilis D1-2-supplemented groups had higher intestinal microbial richness and diversity than the control group. The beta diversity analysis indicated that the bacterial communities in the B. subtilis D1-2-supplemented groups were quite similar but different from the bacterial communities in the control group. Dietary supplementation with B. subtilis D1-2 increased the relative abundance of some potential probiotic-related genera, including Lactobacillus, Clostridium, Lactococcus, Bifidobacterium and Streptococcus. In conclusion, dietary addition of B. subtilis D1-2 could effectively promote the growth of A. japonicus, improve its digestion and immunity capacity to a certain extent, and actively regulate the intestinal microflora of A. japonicus.

Characteristic and antibacterial effect of a histone H2A and its preliminary roles in extracellular traps in manila clam Ruditapes philippinarum.

In the present study, a histone H2A (designed as RpH2A) was identified and characterized from clam Ruditapes philippinarum, and its open reading frame (ORF) was of 387 bp encoding a polypeptide of 128 amino acids. The deduced amino acid sequence of RpH2A shared high identities ranging from 57.1% to 96.1% with that of other identified H2A. The mRNA expression of RpH2A was up-regulated significantly after Vibrio anguillarum challenge. The recombinant RpH2A protein (rRpH2A) displayed significantly binding affinity to lipopolysaccharide (LPS) and peptidoglycan (PGN) in vitro, and also exhibited antimicrobial properties against Escherichia coli. In addition, the antimicrobial RpH2A was shown to co-localize with extracellular traps (ETs) released from hemocytes induced by E. coli, suggesting that RpH2A might contribute to eliminate invading bacteria in clam ETs. Altogether, our data revealed that RpH2A could function as antimicrobial peptides, which might play a crucial role in the immune responses of hemocytes ETs in clams.

A single-CRD C-type lectin from Haliotis discus hannai acts as pattern recognition receptor enhancing hemocytes opsonization.

C-type lectins (CTLs), as a member of the Ca2+-dependent carbohydrate recognition protein superfamily, play multiple roles in non-self recognition and the elimination of invading pathogens. In this study, a C-type lectin was identified and characterized from the Pacific abalone Haliotis discus hannai (designed as HdClec), and its open reading frame (ORF) encoded a polypeptide of 163 amino acids containing a typical signal peptide and only one carbohydrate-recognition domain (CRD). The deduced amino acid sequence of CRD in HdClec shared identities ranging from 22.4% to 39.8% with that of other identified CRDs of CTLs. A novel NPN motif was found in Ca2+-binding site 2 of HdClec. The mRNA transcripts of HdClec were detectable in all the examined tissues of non-stimulated abalones, with the highest expression in hepatopancreas (224.13-fold of that in gills). The expression of HdClec mRNA in hemocytes was significantly up-regulated after Vibrio harveyi challenge. Recombinant HdClec protein (rHdClec) could bind lipopolysaccharide (LPS) and peptidoglycan (PGN) in vitro in the presence of Ca2+. Coinciding with the PAMPs binding assay, rHdClec displayed broad agglutination activities towards Gram-negative bacteria V. splendidus, V. anguillarum, V. parahaemolyticus, V. harveyi, Escherichia coli, and Gram-positive bacteria Micrococcus luteus. Moreover, rHdClec could significantly elicit the chemotactic response of hemocytes in vitro. And the phagocytosis and encapsulation ability of hemocytes could be significantly enhanced by rHdClec. All these results showed that HdClec could function as pattern recognition receptors (PRRs) and further enhance the opsonization of hemocytes, which might play a crucial role in the innate immune responses of Pacific abalone.

Identification, antibacterial activities and action mode of two macins from manila clam Venerupis philippinarum.

In this study, two macins were identified from clam Venerupis philippinarum (designated as VpMacin-1 and VpMacin-2). They showed 64.71% similarity with each other. The highest mRNA expression of VpMacin-1 and VpMacin-2 was detected in gills and hepatopancreas, respectively, in non-stimulated clams, and their expression could be induced significantly in hemocytes after Vibrio anguillarum infection. Silencing of VpMacin-1 and VpMacin-2 led to 22% and 49% mortality 6 days post infection. Escherichia coli cells were killed by recombinant protein rVpMacin-1 and rVpMacin-2 within 1000 and 400 min, respectively, at a concentration of 1.0 × MIC. Compared with rVpMacin-1, rVpMacin-2 not only showed higher broad-spectrum antimicrobial activities towards Vibrio strains, but possessed stronger abilities to inhibit the formation of bacterial biofilm. Both membrane integrity and electrochemical assay indicated that rVpMacins were capable of causing bacterial membrane permeabilization, especially for rVpMacin-2. Besides, rVpMacin-1 significantly induced both phagocytic (0.1 and 1.0 × MIC, p < 0.05) and chemotactic effects (0.1 × MIC, p < 0.01) of hemocytes, while there was no significant increase for rVpMacin-2. Overall, our results suggested that VpMacin-1 and VpMacin-2 play important roles in host defense against invasive pathogens.

Quantitative microbiome profiling links microbial community variation to the intestine regeneration rate of the sea cucumber Apostichopus japonicus.

The intestinal microbiota may play important roles in regenerating intestine of the sea cucumber Apostichopus japonicus, the underlying mechanism remains unclear. In the present study, a germ-free sea cucumber model was developed, and the intestinal microbial differentiation of faster and slower regenerating A. japonicus individuals during intestine regeneration was analyzed. The results revealed that depletion of the intestinal microbiota resulted in elevated abundance of the potential key players Flavobacteriaceae and Rhodobacteraceae during intestine regeneration and thus promoted the intestine regeneration rate of A. japonicus. Metagenomic analysis revealed that the increased abundance of Flavobacteriaceae elevated the enrichment of genes associated with carbohydrate utilization, whereas the abundant Rhodobacteraceae-enriched genes were associated with polyhydroxybutyrate production. We identified microbiota abundance as a key driver of microbial community alterations, especially beneficial microbiota members, in the developing intestine of A. japonicus. This study provides new insights into the mechanism of host-microbiota interactions related to organ regeneration.

The innovation and practice of "Hand as Foot teaching method" in the teaching of motion system injury course.

BACKGROUND: In view of the teaching characteristics of the motion system injury course and the actual clinical teaching. The orthopedic teaching team of the Affiliated Hospital of Inner Mongolia Medical University took the lead in proposing the "Hand as Foot teaching method" and applied it in clinical teaching. Through this teaching method, students' understanding and memorization of key and difficult issues in motion system injuries are strengthened, teacher-student interaction is increased, and teaching effect is improved.  METHODS: The "Hand as Foot teaching method" was used to teach the key and difficult problems to the clinical undergraduate medical students of Inner Mongolia Medical University, and the teaching process was complemented by PPT + model teaching aids. RESULTS: The "Hand as Foot teaching method" is generally welcomed by medical students and has achieved good teacher-student interaction, and is effective in understanding and remembering difficult knowledge points. CONCLUSION: The "Hand as Foot teaching method" is a novel teaching method that can be applied in clinical teaching. This image teaching method improves the teaching effect, enlivens the classroom atmosphere, and enhances the interaction between teachers and students, which makes students' learning process from abstract to intuitive, from simple rote memorization to comprehension and memory, and achieves satisfactory results. It can complement each other with the traditional teaching method of pure PPT + teaching aids model, and to some extent it is worth promoting in the motion system injury courses.

Pollution Characteristics of Microplastics in Mollusks from the Coastal Area of Yantai, China.

Microplastic pollution to the marine environment is a global issue. This study investigated microplastic pollution in ten species of different mollusks. Microplastic shape and size were determined under a microscope. Additionally, the polymer types were identified using Fourier transform infrared microspectroscopy (µ-FT-IR). The results showed that the microplastic abundance varied from 0.19 to 1.76 items/g (wet weight) and 4.3 to 36.6 items/individual. Four types of microplastics were observed, including fibers, fragments, films, and pellets. Fibers smaller than 500 µm were the most common. Cellophane (CP) and polyethylene terephthalate (PET) were the main polymer types. The microplastic abundance in the buried bivalve Ruditapes philippinarum demonstrated the highest level of microplastic contamination assessed by wet weight (1.76 ± 0.95 items/g). Furthermore, the Spearman correlation test showed that there was a significant negative correlation between the microplastic abundance calculated by weight and the biometric parameters (shell length, shell height and soft tissue wet weight). Our results will provide valuable information for assessment of the potential health risks of microplastics in China's seafood.

Microplastic Pollution in Nearshore Sediment from the Bohai Sea Coastline.

Microplastics are recognized as an emerging global issue in marine environments. In this study, microplastic pollution in subtidal sediments from nine typical stations in the Bohai Sea was investigated. The mean concentration was 458.6 ± 150.0 items/kg of dry weight, varying from 280.0 to 773.4 items/kg. All of the microplastics were categorized according to shape, color and size. Among these microplastics, fiber (77.1%), white/blue/black (85.0%) and small microplastics (< 1500 µm) (82.9%) were the most abundant types. Seven polymer types were identified and were, in decreasing order of abundance, rayon > PE > PS > PP > PET > ABS > PA. The microplastics abundance was of the same order of magnitude as that of other similar areas. The microplastic characteristics suggest that tourism, maritime activities and sewage discharge are possible sources. Our results provide useful information for performing an environmental risk assessment of microplastic pollution in this area.

Early detection of steroid-induced femoral head necrosis using 99mTc-Cys-Annexin V-based apoptosis imaging in a rabbit model.

BACKGROUND: At present, the early diagnosis of femoral head necrosis mainly relies on Magnetic resonance imaging (MRI), and most early patients are difficult to make an accurate diagnosis. Therefore, to investigate the early diagnostic value of 99mTc-Cys-Annexin V Single-photon emission computed tomography (SPECT) imaging were compared with MRI in rabbit models of steroid-induced femoral head necrosis. METHODS: The animal model of steroid-induced femoral head necrosis (SIFHN) was established in 5-month-old healthy New Zealand white rabbits by injecting horse serum into ear vein and methylprednisolone into gluteal muscle, the purpose of modeling is to simulate the actual clinical situation of SIFNH. 99mTc-Cys-Annexin V SPECT imaging and MRI were performed at 2nd week, 4th week, and 6th week after modeling. After that, histopathology was used to verify the success of modeling. Apoptosis was detected by transmission electron microscopy (TEM) and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay (TUNEL). RESULTS: At 2 weeks after the injection of hormone, 99mTc-Cys-Annexin V SPECT image showed abnormal radioactive uptake in the bilateral femoral head. And over time, the radioactivity concentration was more obvious, and the ratio of T/NT (target tissue/non-target tissues, which is the ratio of femoral head and the ipsilateral femoral shaft) was gradually increased. In the 99mTc-Cys-Annexin V SPECT imaging at each time point, T/NT ratio of the model group was significantly higher than that of the control group (P < 0.01); at 4 weeks after the injection of hormone, MRI showed an abnormal signal of osteonecrosis. At 2, 4, and 6 weeks after hormone injection, apoptosis was observed by TUNEL and TEM. CONCLUSIONS: 99mTc-Cys-Annexin V SPECT imaging can diagnose steroid-induced femoral head necrosis earlier than MRI, and has potential application value for non-invasively detecting early and even ultra-early stage of femoral head necrosis.

Antibacterial activities and mechanisms of action of a defensin from manila clam Ruditapes philippinarum.

Defensins represent an evolutionary ancient family of antimicrobial peptides, which played an undeniably important role in host defense. In the present study, a defensin isoform was identified and characterized from manila clam Ruditapes philippinarum (designed as Rpdef1α). Multiple alignments and phylogenetic analysis suggested that Rpdef1α belonged to the defensin family. Quantitative RT-PCR and immunohistochemical analysis revealed that Rpdef1α transcripts and the encoding peptide were dominantly expressed in the tissues of gills and mantle. After Vibrio anguillarum challenge, the Rpdef1α transcripts were significantly up-regulated in gills of clams. In addition, rRpdef1α not only showed broad-spectrum antimicrobial activities towards Vibrio species, but also inhibited the formation of bacterial biofilms. Knockdown of Rpdef1α transcripts caused significant increase in the cumulative mortality of manila clams post V. anguillarum challenge. Membrane integrity, scanning electron microscopy analysis and electrochemical assay indicated that rRpdef1α was capable of causing bacterial membrane permeabilization and then resulted in cell death. Moreover, phagocytosis and chemotactic ability of hemocytes could be significantly enhanced after incubation with rRpdef1α. Overall, these results suggested that Rpdef1α could act as both antibacterial agent and opsonin to defend against the invading microorganisms in manila clam R. philippinarum.

Combined lateral peripatellar and posteromedial approaches for Schatzker type IV tibial plateau fractures involving posteromedial plane: a prospective study.

BACKGROUND: The objective of this study to evaluate prospectively the effectiveness of Schatzker type IV tibial plateau fractures involving posteromedial plane managed by combined lateral peripatellar and posteromedial approaches. METHODS: We analyzed 18 patients with Schatzker type IV tibial plateau fractures involving posteromedial plane. There were 12 males and 6 females with an average of 38.5 years (range, 25-60 years). The mechanism of injury included traffic accident in 15 patients and falling in 3 patients. The injured lower limbs were right in 11 patients and left in 7 patients. The mean time from injury to surgery was 6.78 days (range, 5-9 days). There were 8 patients with meniscus injuries in our study. RESULTS: The mean operation time was 3.41 h (range, 3-4 h). The mean blood loss was 352.78 ml (range, 300-410 ml). All the injured meniscuses were repaired. All patients were followed up, and the average time of follow up was 16.61 months (range, 14-22 months). Bone union was achieved at a mean of 12 weeks (range, 10-14 weeks). The mean degree of knee extension was 1.11° (range, 0-5°), and the mean degree of knee flexion was 120.56° (range, 110-130°). The mean points of KSS were 83 (range, 74-89 points). According to the criteria of KSS, 14 patients had clinical outcomes rated as excellent and 4 patients were rated as good. CONCLUSION: Our results suggested that Combined lateral peripatellar and posteromedial approaches in the treatment of Schatzker type IV tibial plateau fractures involving posteromedial plane acquired satisfying outcomes. It was good for repairing the injured meniscus through our approaches.