Potential of UV-B radiation in drought stress resilience: A multidimensional approach to plant adaptation and future implications.

The escalating impact of climate change and ultraviolet (UV) radiation is subjecting plants to unique combinations of UV-B and drought stress. These combined stressors could have additive, synergistic, or antagonistic effects, but the precise nature of these impacts remains uncertain, hampering our ability to predict plant adaptations approach towards stressors. Our analysis of various studies shows that UV-B or drought conditions detrimentally influence plant growth and health metrics by the enhanced generation of reactive oxygen species causing damage to lipids, proteins, carbohydrates and DNA. Further reducing biomass accumulation, plant height, photosynthetic efficiency, leaf area, and water transpiration, while enhancing stress-related symptoms. In response to UV-B radiation and drought stress, plants exhibit a notable up-regulation of specific acclimation-associated metabolites, including proline, flavonoids, anthocyanins, unsaturated fatty acids, and antioxidants. These metabolites play a pivotal role in conferring protection against environmental stresses. Their biosynthesis and functional roles are potentially modulated by signalling molecules such as hydrogen peroxide, abscisic acid, jasmonic acid, salicylic acid, and ethylene, all of which have associated genetic markers that further elucidate their involvement in stress response pathways. In comparison to single stress, the combination of UV-B and drought induces the plant defence responses and growth retardation which are less-than-additive. This sub-additive response, consistent across different study environments, suggests the possibility of a cross-resistance mechanism. Our outlines imply that the adverse effects of increased drought and UV-B could potentially be mitigated by cross-talk between UV-B and drought regimes utilizing a multidimensional approach. This crucial insight could contribute significantly to refining our understanding of stress tolerance in the face of ongoing global climate change.

First Report of Alternaria gossypina Causing Stem Base Rot on Passilora edulis in Guangxi, China.

Passion fruit (Passilora edulis), known as the "king of fruit juices", is popular in southern China (Yuan et al. 2019). Stem base rot is a devastating disease of passion fruit commonly caused by several Fusarium spp. (Zakaria, 2022). In July 2022, typical symptoms of stem base rot were observed in a poorly managed "Qinmi No. 9" Golden passion fruit orchard in Jingxi (23°13'10"N, 106°5'23"E). The disease incidence had reached 40% (n=200) in the survey. Symptoms included ulceration and mutilation at the stem base, making the plants prone to breakage when pulled, wilting and drooping leaves above ground, and severe cases leading to the entire plant withering and dying. Fourteen plants with obvious symptoms were collected. Thin sections of plant tissue were cut from junction of sickness and health of stem, sterilized with ethanol and sodium hypochlorite, and placed on PDA medium at 28°C. Sixty fungal strains were obtained, 90% of which was identified as Fusarium based on morphology. 80% of Fusarium were F. oxysporum species complex (FOSC), but pathogenicity experiment showed all FOSC were weakly pathogenic. However, two severely pathogenic fungi with similar morphology but distinct from Fusarium were identified from the same plant. The representative strain C11 was selected for further study. C11 demonstrated a rapid growth rate, reaching a 90 mm diameter colony on PDA cultured at 25°C for 7 days. The colony displaced a round, flat shape with an overall light brown front, and cottony gray or light brown mycelium, while the reverse side was dark brown. Conidia production was observed as typically occurred in multiple chains after 14 days culture on OA medium, with round, oval or straight rod-like brown conidia ranging in size from 5.74-23.42×14.67-67.22, featuring 1-8 transverse septa and 0-3 mediastinum (Figure S1). For molecular identification, the internal transcribed spacer (ITS, OR616614), translation elongation factor 1-alpha (TEF, OR633298), alternaria major allergen (Alt a1, OR633294) gene, glyceraldehyde 3-phosphate dehydrogenase (GAPDH, OR633295), RNA polymerase subunit II gene (RPB2, OR633297), 18S Small subunit rDNA (SSU, OR616608) , 28S Large Subunit rDNA (LSU, OR616615), the KOG1058 gene regions (OR633296) and an approximately segment of the anonymous noncoding region (OPA10-2, OR633299) were amplified from C11 (Liu et al. 1999, Li et al. 2023, Andrew et al. 2009), and deposited in GenBank with accession number shown in the brackets. Phylogenetic trees were constructed in MEGA11 after splicing by BioEdit (Figure S3). Combining morphology and molecular analyses, C11 was identified as Alternaria gossypina (Woudenberg et al. 2015). To test the pathogenicity, the base of the seedling stem (20cm in height) of 50 healthy "Tainong No. 1" variety of purple passion fruit, which was more susceptible to stem-base rot, was puncture wound with needles, inoculated with 6 mm diameter colonies of fungi, and then wrapped in wet cotton (Ángel et al. 2018). Ten healthy seedlings inoculated with PDA were used as controls. These plants were cultured in an artificial greenhouse at 30±5℃with 80±5% humidity. After 15 days, the plants inoculated with C11 exhibited symptoms similar to those in the field, whereas the controls remained healthy. A. gossypina was reisolated from the diseased plant stems, with the morphology and GAPDH sequence consistent with the inoculated (Figure S1, S2). This is the first report of passion fruit stem rot caused by A. gossypina. This finding will aid in the prevention and control of stem rot in passion fruit.

Biomechanical properties of articular cartilage in different regions and sites of the knee joint: acquisition of osteochondral allografts.

Osteochondral allograft (OCA) transplantation involves grafting of natural hyaline cartilage and supporting subchondral bone into the cartilage defect area to restore its biomechanical and tissue structure. However, differences in biomechanical properties and donor-host matching may impair the integration of articular cartilage (AC). This study analyzed the biomechanical properties of the AC in different regions of different sites of the knee joint and provided a novel approach to OCA transplantation. Intact stifle joints from skeletally mature pigs were collected from a local abattoir less than 8 h after slaughter. OCAs were collected from different regions of the joints. The patella and the tibial plateau were divided into medial and lateral regions, while the trochlea and femoral condyle were divided into six regions. The OCAs were analyzed and compared for Young's modulus, the compressive modulus, and cartilage thickness. Young's modulus, cartilage thickness, and compressive modulus of OCA were significantly different in different regions of the joints. A negative correlation was observed between Young's modulus and the proportion of the subchondral bone (r = - 0.4241, P < 0.0001). Cartilage thickness was positively correlated with Young's modulus (r = 0.4473, P < 0.0001) and the compressive modulus (r = 0.3678, P < 0.0001). During OCA transplantation, OCAs should be transplanted in the same regions, or at the closest possible regions to maintain consistency of the biomechanical properties and cartilage thickness of the donor and recipient, to ensure smooth integration with the surrounding tissue. A 7 mm depth achieved a higher Young's modulus, and may represent the ideal length.

Gut microbiome features associated with liver fibrosis in Hispanics, a population at high risk for fatty liver disease.

BACKGROUND AND AIMS: Hispanics are disproportionately affected by NAFLD, liver fibrosis, cirrhosis, and HCC. Preventive strategies and noninvasive means to identify those in this population at high risk for liver fibrosis, are urgently needed. We aimed to characterize the gut microbiome signatures and related biological functions associated with liver fibrosis in Hispanics and identify environmental and genetic factors affecting them. APPROACH AND RESULTS: Subjects of the population-based Cameron County Hispanic Cohort (CCHC; n = 217) were screened by vibration-controlled transient elastography (FibroScan). Among them, 144 (66.7%) had steatosis and 28 (13.0%) had liver fibrosis. The gut microbiome of subjects with liver fibrosis was enriched with immunogenic commensals (e.g., Prevotella copri, Holdemanella, Clostridiaceae 1) and depleted of Bacteroides caccae, Parabacteroides distasonis, Enterobacter, and Marinifilaceae. The liver fibrosis-associated metagenome was characterized by changes in the urea cycle, L-citrulline biosynthesis and creatinine degradation pathways, and altered synthesis of B vitamins and lipoic acid. These metagenomic changes strongly correlated with the depletion of Parabacteroides distasonis and enrichment of Prevotella and Holdemanella. Liver fibrosis was also associated with depletion of bacterial pathways related to L-fucose biosynthesis. Alcohol consumption, even moderate, was associated with high Prevotella abundance. The single-nucleotide polymorphisms rs3769502 and rs7573751 in the NCK adaptor protein 2 (NCK2) gene positively associated with high Prevotella abundance. CONCLUSION: Hispanics with liver fibrosis display microbiome profiles and associated functional changes that may promote oxidative stress and a proinflammatory environment. These microbiome signatures, together with NCK2 polymorphisms, may have utility in risk modeling and disease prevention in this high-risk population.

Distinct Denitrifying Phenotypes of Predominant Bacteria Modulate Nitrous Oxide Metabolism in Two Typical Cropland Soils.

Denitrifying nitrous oxide (N2O) emissions in agroecosystems result from variations in microbial composition and soil properties. However, the microbial mechanisms of differential N2O emissions in agricultural soils are less understood. In this study, microcosm experiments using two main types of Chinese cropland soil were conducted with different supplements of nitrate and glucose to simulate the varying nitrogen and carbon conditions. The results show that N2O accumulation in black soil (BF) was significantly higher than that in fluvo-aquic soil (FF) independent of nitrogen and carbon. The abundance of most denitrifying genes was significantly higher in FF, but the ratios of genes responsible for N2O production (nirS and nirK) to the gene responsible for N2O reduction (nosZ) did not significantly differ between the two soils. However, the soils showed obvious discrepancies in denitrifying bacterial communities, with a higher abundance of N2O-generating bacteria in BF and a higher abundance of N2O-reducing bacteria in FF. High accumulation of N2O was verified by the bacterial isolates of Rhodanobacter predominated in BF due to a lack of N2O reduction capacity. The dominance of Castellaniella and others in FF led to a rapid reduction in N2O and thus less N2O accumulation, as demonstrated when the corresponding isolate was inoculated into the studied soils. Therefore, the different phenotypes of N2O metabolism of the distinct denitrifiers predominantly colonized the two soils, causing differing N2O accumulation. This knowledge would help to develop a strategy for mitigating N2O emissions in agricultural soils by regulating the phenotypes of N2O metabolism.

Chameleon-like Anammox Bacteria for Surface Color Change after Suffering Starvation.

Bacteria are often exposed to long-term starvation during transportation and storage, during which a series of enzymes and metabolic pathways are activated to ensure survival. However, why the surface color of the bacteria changes during starvation is still not well-known. In this study, we found black anammox consortia suffering from long-term starvation contained 0.86 mmol gVSS-1 cytochrome c, which had no significant discrepancy compared with the red anammox consortia (P > 0.05), indicating cytochrome c was not the key issue for chromaticity change. Conversely, we found that under starvation conditions cysteine degradation is an important metabolic pathway for the blackening of the anammox consortia for H2S production. In particular, anammox bacteria contain large amounts of iron-rich nanoparticles, cytochrome c, and other iron-sulfur clusters that are converted to produce free iron. H2S combines with free iron in bacteria to form Fe-S compounds, which eventually exist stably as FeS2, mainly in the extracellular space. Interestingly, FeS2 could be oxidized by air aeration, which makes the consortia turn red again. The unique self-protection mechanism makes the whole consortia appear black, avoiding inhibition by high concentrations of H2S and achieving Fe storage. This study expands the understanding of the metabolites of anammox bacteria as well as the bacterial survival mechanism during starvation.

Prevention of sclerosis around cannulated screw after treatment of femoral neck fractures with bioceramic nails: a finite element analysis.

PURPOSE: Conventional cannulated screws (CS) are the main treatment method for femoral neck fractures (FNF). However, the rate of femoral head necrosis remains high after FNF treatment. The study aimed to compare the biomechanical features of different internal fixation materials for the treatment of Pauwel type III FNF to explore new strategies for clinical management. METHODS: A new material was prepared by applying casting, freeze drying and sintering process. The independently developed calcium magnesium silicate ceramic powder and hydrogel solution were evenly mixed to obtain a high-viscosity bio-ink, and a bioceramic nail (BN) with high mechanical strength and high fracture toughness was successfully prepared. Four internal fixations were developed to establish the Pauwel type III FNF and healed fracture finite element models: A, three CSs; B, three BNs; C, two BNs and one CS; D, one BN and two CSs. Von Mises stress and displacement of the implants and femur were observed. RESULTS: The measured Mg content in ceramic powder was 2.08 wt%. The spectral data confirmed that the ceramic powder has high crystallinity, which coincides with the wollastonite-2 M (PDF# 27-0088). The maximum von Mises stresses for the four models were concentrated in the lower part of the fracture surface, at 318.42 Mpa, 103.52 MPa, 121.16 MPa, and 144.06 MPa in models A, B, C, and D, respectively. Moreover, the maximum Von-mises stresses of the implants of the four models were concentrated near the fracture end at 243.65 MPa (A) and 58.02 MPa (B), 102.18 MPa (C), and 144.06 MPa (D). The maximum displacements of the four models were 5.36 mm (A), 3.41 mm (B), 3.60 mm (C), and 3.71 mm (D). The displacements of the three models with BNs were similar and smaller than that of the triple CS fracture model. In the fracture healing models with and without three CSs, the greatest stress concentration was scattered among the lowest screw tail, femoral calcar region, and lateral femur shaft. The displacement and stress distributions in both models are generally consistent. The stress distribution and displacement of the three healed femoral models with BNs were essentially identical to the healing models with three CSs. The maximum von Mises stresses were 65.94 MPa (B), 64.61 MPa (C), and 66.99 MPa (D) while the maximum displacements of the three healed femoral models were 2.49 mm (B), 2.56 mm (C), and 2.49 mm (D), respectively. CONCLUSIONS: Bioceramic nails offer greater advantages than conventional canulated screws after femoral neck fractures. However, the combination of bioceramic nails and CSs is more clinically realistic; replacing all internal fixations with bioceramic nails after the healing of femoral neck fractures can solve the problem of sclerosis formation around CSs and improve bone reconstruction by their bioactivity.

Tumor attachment to Major intrahepatic vascular for Colorectal liver metastases.

BACKGROUND: Colorectal liver metastases attached major intrahepatic vessels has been considered to be a risk factor for survival outcome after liver resection. The present study aimed to clarify the outcomes of R1 surgery (margin < 1 mm) in CRLM patients, distinguishing parenchymal margin R1 and attached to major intrahepatic vessels R1. METHODS: In present study, 283 CRLM patients who were evaluated to be attached to major intrahepatic vessels initially and underwent liver resection following preoperative chemotherapy. They were assigned to two following groups: R0 (n = 167), R1 parenchymal (n = 58) and R1 vascular (n = 58). The survival outcomes and local recurrence rates were analyzed in each group. RESULTS: Overall, 3- and 5-year overall survival rates after liver resection were 53.0% and 38.2% (median overall survival 37 months). Five-year overall survival was higher in patients with R0 than parenchymal R1 (44.9%% vs. 26.3%, p = 0.009), whereas there was no significant difference from patients with vascular R1 (34.3%, p = 0.752). In the multivariable analysis, preoperative chemotherapy > 4 cycles, clinical risk score 3-5, RAS mutation, parenchymal R1 and CA199 > 100 IU/ml were identified as independent predictive factors of overall survival (p < 0.05). There was no significant difference for local recurrence among three groups. CONCLUSION: Parenchymal R1 resection was independent risk factor for CRLM. Vascular R1 surgery achieved survival outcomes equivalent to R0 resection. Non-anatomic liver resection for CRLM attached to intrahepatic vessels might be pursued to increase patient resectability by preoperative chemotherapy.

GigaAssay - An adaptable high-throughput saturation mutagenesis assay platform.

High-throughput assay systems have had a large impact on understanding the mechanisms of basic cell functions. However, high-throughput assays that directly assess molecular functions are limited. Herein, we describe the "GigaAssay", a modular high-throughput one-pot assay system for measuring molecular functions of thousands of genetic variants at once. In this system, each cell was infected with one virus from a library encoding thousands of Tat mutant proteins, with each viral particle encoding a random unique molecular identifier (UMI). We demonstrate proof of concept by measuring transcription of a GFP reporter in an engineered reporter cell line driven by binding of the HIV Tat transcription factor to the HIV long terminal repeat. Infected cells were flow-sorted into 3 bins based on their GFP fluorescence readout. The transcriptional activity of each Tat mutant was calculated from the ratio of signals from each bin. The use of UMIs in the GigaAssay produced a high average accuracy (95%) and positive predictive value (98%) determined by comparison to literature benchmark data, known C-terminal truncations, and blinded independent mutant tests. Including the substitution tolerance with structure/function analysis shows restricted substitution types spatially concentrated in the Cys-rich region. Tat has abundant intragenic epistasis (10%) when single and double mutants are compared.

Isolation, Identification and Molecular Mechanism Analysis of the Nematicidal Compound Spectinabilin from Newly Isolated Streptomyces sp. DT10.

Plant parasitic nematodes (PPNs) are highly destructive and difficult to control, while conventional chemical nematicides are highly toxic and cause serious environmental pollution. Additionally, resistance to existing pesticides is becoming increasingly common. Biological control is the most promising method for the controlling of PPNs. Therefore, the screening of nematicidal microbial resources and the identification of natural products are of great significance and urgency for the environmentally friendly control of PPNs. In this study, the DT10 strain was isolated from wild moss samples and identified as Streptomyces sp. by morphological and molecular analysis. Using Caenorhabditis elegans as a model, the extract of DT10 was screened for nematicidal activity, which elicited 100% lethality. The active compound was isolated from the extracts of strain DT10 using silica gel column chromatography and semipreparative high-performance liquid chromatography (HPLC). The compound was identified as spectinabilin (chemical formula C28H31O6N) using liquid chromatography mass spectrometry (LC-MS) and nuclear magnetic resonance (NMR). Spectinabilin exhibited a good nematicidal activity on C. elegans L1 worms, with a half-maximal inhibitory concentration (IC50) of 2.948 µg/mL at 24 h. The locomotive ability of C. elegans L4 worms was significantly reduced when treated with 40 µg/mL spectinabilin. Further analysis of spectinabilin against known nematicidal drug target genes in C. elegans showed that it acts via target(s) different from those of some currently used nematicidal drugs such as avermectin and phosphine thiazole. This is the first report on the nematicidal activity of spectinabilin on C. elegans and the southern root-knot nematode Meloidogyne incognita. These findings may pave the way for further research and application of spectinabilin as a potential biological nematicide.

Different gain modulations of selective attention at short and long cue-target delays.

Previous studies have tested attentional gain patterns, for example, within the normalization model of attention (NMoA), by altering the relative sizes of the attention field and stimuli. Existing studies have not investigated whether the gain patterns of altering the relative exogenous cue size as compared with the target stimuli matches the prediction of NMoA and whether these gain patterns exist in the late stage of attentional processing. To resolve these questions, the present study maintained the target grating size and changed the exogenous cue size in both short and long cue-target onset asynchronies (CTOAs) conditions. The results revealed response gain for small cue/large target size conditions and contrast gain for large cue/small target size conditions, which was consistent with the NMoA. However, we observed the decrease in the contrast gain factor only with long CTOAs, regardless of whether the cue size was relatively small or large. This indicated that NMoA-related effects based on the relative attentional field dominated in the early stage and that the contrast gain dominated in the late stage.

How college-student academic undermatch affects students: Quasi-experimental evidence on multifaceted student outcomes.

Undermatching is a phenomenon in which students attend institutions that are less selective than the ones they could enroll given their academic credentials. Recent research suggests that undermatching may harm student development during college. However, there have been few comprehensive analyses of the causal relationship of undermatching and multifaceted college experience. Using college student longitudinal data from Beijing, China, we provide new quasi-experimental evidence on the effects of academic undermatch. This study extends the existing literature by focusing on a wide variety of student outcomes during college years, including learning motivation, behavior and academic performance, psychological attitudes and mental health, interpersonal relationships and involvement, and college satisfaction. Employing the exogenous admissions reform as the instrumental variable for undermatching, we find that undermatching predicts better academic performance and self-evaluation, but worse social relationships and college satisfaction. The results suggest that, although undermatched students are usually higher academic achievers than their college peers, they lack group identity and are not socially involved in college life.

The Regulatory Network Involving PcoR, RsaL, and MvaT Coordinates the Quorum-Sensing System in Pseudomonas fluorescens 2P24.

Pseudomonas fluorescens 2P24 is a beneficial plant root-associated microorganism capable of suppressing several soilborne plant diseases. The capacity of P. fluorescens to aggressively colonize the rhizosphere is an important requirement for its biocontrol trait. We previously found that the PcoI/PcoR quorum-sensing system (QS) is involved in regulating the rhizosphere colonization of P. fluorescens. Here, we revealed a sophisticated regulatory network that connects PcoR, RsaL, and MvaT proteins to fine-tune the PcoI/PcoR QS system. Our data showed that PcoR could directly bind to the promoter region of pcoI thereby inducing the PcoI/PcoR QS system, whereas RsaL binds simultaneously with PcoR to the promoter region of pcoI and represses the PcoR-dependent activation of pcoI gene. In addition, RsaL indirectly downregulates the expression of pcoR. Furthermore, we showed that disruption of mvaT enhanced the expression of pcoI, pcoR, and rsaL, whereas MvaT controls the PcoI/PcoR QS in a RsaL-independent manner. Overall, this study elucidates that PcoR, RsaL, and MvaT regulate the PcoI/PcoR QS through a multi-tiered regulatory mechanism and that PcoR is necessary in the RsaL- and MvaT-mediated repression on the expression of pcoI. IMPORTANCE The PcoI/PcoR quorum-sensing system of Pseudomonas fluorescens 2P24 is important for its effective colonization in the plant rhizosphere. Many regulatory elements appear to directly or indirectly influence the QS system. Here, we found a complex regulatory network employing transcriptional factors PcoR, RsaL, and MvaT to influence the expression of the PcoI/PcoR QS in P. fluorescens 2P24. Our results indicate that PcoR and RsaL directly bind to the promoter region of pcoI and then positively and negatively regulate the expression of pcoI, respectively. Furthermore, the H-NS family protein MvaT negatively controls the PcoI/PcoR QS in a RsaL-independent manner. Taken together, our data provide new insights into the interplays between different regulatory elements that fine-tune the QS system of P. fluorescens.

Metagenomes of rectal swabs in larger, advanced stage cervical cancers have enhanced mucus degrading functionalities and distinct taxonomic structure.

BACKGROUND: Gut microbiome community composition differs between cervical cancer (CC) patients and healthy controls, and increased gut diversity is associated with improved outcomes after treatment. We proposed that functions of specific microbial species adjoining the mucus layer may directly impact the biology of CC. METHOD: Metagenomes of rectal swabs in 41 CC patients were examined by whole-genome shotgun sequencing to link taxonomic structures, molecular functions, and metabolic pathway to patient's clinical characteristics. RESULTS: Significant association of molecular functions encoded by the metagenomes was found with initial tumor size and stage. Profiling of the molecular function abundances and their distributions identified 2 microbial communities co-existing in each metagenome but having distinct metabolism and taxonomic structures. Community A (Clostridia and Proteobacteria predominant) was characterized by high activity of pathways involved in stress response, mucus glycan degradation and utilization of degradation byproducts. This community was prevalent in patients with larger, advanced stage tumors. Conversely, community B (Bacteroidia predominant) was characterized by fast growth, active oxidative phosphorylation, and production of vitamins. This community was prevalent in patients with smaller, early-stage tumors. CONCLUSIONS: In this study, enrichment of mucus degrading microbial communities in rectal metagenomes of CC patients was associated with larger, more advanced stage tumors.

Pilot investigation on biostability of drinking water distribution systems under water source switching.

Water quality deterioration of drinking water distribution systems (DWDSs) caused by water source switching has been reported previously. However, systematic investigation of the biostability of DWDS under water source switching is limited. Aged pipes, including three commonly used pipe materials dug out from a practical DWDS, were used to systematically investigate the biofilm stability mechanism of DWDS under water source switching to quality-improved water. An increase in adenosine triphosphate (ATP) concentration in the bulk water during the initial stage of the switching period was observed, indicating the risk of biofilm release through aged pipe surfaces after water source switching. Sloughing of biofilms might contribute to temporary instability. From day 35, the ATP concentration in the polyethylene (PE) and plastic stainless steel composite (PS) pipes were maintained at approximately 2.40 and 2.56 ng/L, respectively. In contrast, the ATP concentration in the ductile iron (DI) pipes was higher, at approximately 3.43 ng/L from day 42. The water quality variation could cause areas of the biofilm to slough and reduce the biomass of biofilm, causing partial alteration of the microbial community. 16S rRNA gene amplicon sequencing-based functional prediction revealed that the biofilm could increase the abundance of chlorine-resistant bacteria attributed to the increase in Pseudomonas and Methylobacterium after switching to quality-improved water. Moreover, the profiles of specific pathways linked to human diseases, antibiotic resistance, and antibiotic biosynthesis revealed that the safety of the biofilm could improve after switching to quality-improved water. KEY POINTS: • The PE and PS biofilm showed improved resistance to water quality perturbation. • Greater number of Methylobacterium was found in the biofilm after water source switching. • 3.16S gene-based metagenomics prediction revealed that the safety of the biofilm under water source switching.

Comparison of femoral mechanics before and after internal fixation removal and the effect of sclerosis on femoral stress: a finite element analysis.

BACKGROUND: Femoral neck fractures are a common traumatic injury. The removal of the internal fixation remains controversial, especially in terms of mechanical stability. Moreover, collapsed necrosis of the femoral head continues to occur after fracture healing. We believe that sclerotic cancellous bone (SCB) formation around the screw is associated with femoral head necrosis. We aimed to compare mechanical features before and after implant removal and determine the effect of SCB formation on stress distribution. METHODS: Cylindrical cancellous bone sections were collected from a relatively normal region and an SCB region of a necrotic femoral head, and their elastic moduli were measured. Four femoral finite element models were developed: a) femoral neck fracture healing with implants, b) fracture healing without implants, c) sclerosis around the screw with implants, and d) sclerosis around the screw without implants. RESULTS: The maximum von Mises peak stresses of models a and b were 66.643 MPa and 63.76 MPa, respectively, and were concentrated in the upper lateral femur. The main stress was scattered at the lowest screw tail, femoral calcar region, and lateral femur shaft. Moreover, coronal plane strain throughout the screw paths near the femoral head in models a and b was mostly in the range of 1000-3000 µÎµ. The maximum stress concentrations in models c and d were located at the lower femoral head and reached 91.199 MPa and 78.019 MPa, respectively. CONCLUSIONS: The stresses in the sclerotic model around the cannulated screws are more concentrated on the femoral head than in the healing model without sclerotic bone. The overall stresses in the healing femoral neck fracture model were essentially unchanged before and after removal of the internal fixation.

XRCC4 and MRE11 Roles and Transcriptional Response to Repair of TALEN-Induced Double-Strand DNA Breaks.

Double-strand breaks (DSB) are one of the most lethal forms of DNA damage that, if left unrepaired, can lead to genomic instability, cellular transformation, and cell death. In this work, we examined how repair of transcription activator-like effector nuclease (TALEN)-induced DNA damage was altered when knocking out, or inhibiting a function of, two DNA repair proteins, XRCC4 and MRE11, respectively. We developed a fluorescent reporter assay that uses TALENs to introduce DSB and detected repair by the presence of GFP fluorescence. We observed repair of TALEN-induced breaks in the XRCC4 knockout cells treated with mirin (a pharmacological inhibitor of MRE11 exonuclease activity), albeit with ~40% reduced efficiency compared to normal cells. Editing in the absence of XRCC4 or MRE11 exonuclease was robust, with little difference between the indel profiles amongst any of the groups. Reviewing the transcriptional profiles of the mirin-treated XRCC4 knockout cells showed 307 uniquely differentially expressed genes, a number far greater than for either of the other cell lines (the HeLa XRCC4 knockout sample had 83 genes, and the mirin-treated HeLa cells had 30 genes uniquely differentially expressed). Pathways unique to the XRCC4 knockout+mirin group included differential expression of p53 downstream pathways, and metabolic pathways indicating cell adaptation for energy regulation and stress response. In conclusion, our study showed that TALEN-induced DSBs are repaired, even when a key DSB repair protein or protein function is not operational, without a change in indel profiles. However, transcriptional profiles indicate the induction of unique cellular responses dependent upon the DNA repair protein(s) hampered.

Towards sustainable agriculture: rhizosphere microbiome engineering.

Soil microbiomes are extremely complex, with dense networks of interconnected microbial species underpinning vital functions for the ecosystem. In advanced agricultural research, rhizosphere microbiome engineering is gaining much attention, as the microbial community has been acknowledged to be a crucial partner of associated plants for their health fitness and yield. However, single or combined effects of a wide range of soil biotic and abiotic factors impact the success of engineered microbiomes, as these microbial communities exhibit uneven structural and functional networks in diverse soil conditions. Therefore, once a deep understanding of major influential factors and corresponding microbial responses is developed, the microbiome can be more effectively manipulated and optimized for cropping benefits. In this mini-review, we propose the concept of a microbiome-mediated smart agriculture system (MiMSAS). We summarize some of the advanced strategies for engineering the rhizosphere microbiome to withstand the stresses imposed by dominant abiotic and biotic factors. This work will help the scientific community gain more clarity about engineered microbiome technologies for increasing crop productivity and environmental sustainability.Key points• Individual or combined effects of soil biotic and abiotic variables hamper the implementation of engineered microbiome technologies in the field.• As a traditional approach, reduced-tillage practices coinciding with biofertilization can promote a relatively stable functional microbiome.• Increasing the complexity and efficiency of the synthetic microbiome is one way to improve its field-application success rate.• Plant genome editing/engineering is a promising approach for recruiting desired microbiomes for agricultural benefit.

Crossmodal Nonspatial Repetition Inhibition Due to Modality Shift.

Previous studies have found that processing of a second stimulus is slower when the modality of the first stimulus differs, which is termed the modality shift effect. Moreover, people tend to respond more slowly to the second stimulus when the two stimuli are similar in the semantic dimension, which is termed the nonspatial repetition inhibition effect. This study aimed to explore the modality shift effect on nonspatial repetition inhibition and whether such modulation was influenced by different temporal intervals. A cue-target paradigm was adopted in which modality priming and identity priming were manipulated at three interstimuli intervals. The results showed that the response times under the modality shift condition were slower than those under the modality repeat condition. In trials with modality shift, responses to congruent cues and targets were slower than to incongruent cue-target combinations, indicating crossmodal nonspatial repetition inhibition. The crossmodal nonspatial repetition inhibition effect decreased with increasing interstimuli interval. These results provide evidence that the additional intervening event proposed in previous studies is not necessary for the occurrence of crossmodal nonspatial repetition inhibition.

Hypoxia preconditioning protects neuronal cells against traumatic brain injury through stimulation of glucose transport mediated by HIF-1α/GLUTs signaling pathway in rat.

Hypoxia preconditioning (HPC), a well-established preconditioning model, has been shown to protect the brain against severe hypoxia or ischemia caused by traumatic brain injury (TBI), but the mechanism has not been well elucidated. Anaerobic glycolysis is the major way for neurons to produce energy under cerebral ischemia and hypoxia after TBI, and it requires large amounts of glucose. We hypothesized that glucose transport, as a rate-limiting step of glucose metabolism, may play key roles in the neuroprotective effects of HPC on cerebral cortex tissue against TBI. The aim of this study was to investigate the effect of HPC on glucose transport activity of rat cerebral cortex tissue after TBI through examining the gene expression of two major glucose transporters (GLUT1 and GLUT3) and their upstream target gene hypoxia-inducible factor-1α (HIF-1α). Sprague-Dawley rats were treated with HPC (50.47 kPa, 3 h/d, 3d). Twenty-four hours after the last treatment, the rats were injured using the Feeney free falling model. Cortex tissues of injured rats were removed at 1 h, 4 h, 8 h, 12 h, 1 day, 3 days, 7 d, and 14 days post-injury for histological analysis. Compared with TBI alone, HPC before TBI resulted in the expression of HIF-1α, GLUT1, and GLUT3 to increase at 1 h; they were markedly increased at 4 h, 8 h, 12 h, 1 day, and 3 days and decreased thereafter (p < 0.05). HPC before TBI could improve neuronal survival in rats by examining NeuN staining and observing reduced apoptosis by examining TUNEL staining. The result showed that HPC before TBI could increase the expression of GLUT1 and GLUT3. And through double immunofluorescence staining for GLUT3 and NeuN, the results strongly suggest that HPC improved glucose transport activity of neurons in rats with TBI. In summary, our results further support that HPC can improve hypoxia tolerance and attenuate neuronal loss of cerebral cortex in rats after TBI. The mechanism is mainly related to the increase of glucose transport activity through inducing GLUT1 and GLUT3 expression through upregulating HIF-1α expression.