Coupling the fermentation and membrane separation process for polyamides monomer cadaverine production from feedstock lysine

Nylon is a polyamide material with excellent performance used widely in the aviation and automobile industries, and other fields. Nylon monomers such as hexamethylene diamine and other monomers are in huge demand. Therefore, in order to expand the methods of nylon production, we tried to develop alternative bio‐manufacturing processes which would make a positive contribution to the nylon industry. In this study, the engineered E. coli‐overexpressing Lysine decarboxylases (LDCs) were used for the bioconversion of l‐lysine to cadaverine. An integrated fermentation and microfiltration (MF) process for high‐level cadaverine production by E. coli was established. Concentration was increased from 87 to 263.6 g/L cadaverine after six batch coupling with a productivity of 3.65 g/L‐h. The cadaverine concentration was also increased significantly from 0.43 g cadaverine/g l‐lysine to 0.88 g cadaverine/g l‐lysine by repeated batch fermentation. These experimental results indicate that coupling the fermentation and membrane separation process could benefit the continuous production of cadaverine at high levels.     

PPARα alleviates iron overload‐induced ferroptosis in mouse liver

Ferroptosis is an iron‐dependent form of non‐apoptotic cell death implicated in liver, brain, kidney, and heart pathology. How ferroptosis is regulated remains poorly understood. Here, we show that PPARα suppresses ferroptosis by promoting the expression of glutathione peroxidase 4 (Gpx4) and by inhibiting the expression of the plasma iron carrier TRF. PPARα directly induces Gpx4 expression by binding to a PPRE element within intron 3. PPARα knockout mice develop more severe iron accumulation and ferroptosis in the liver when fed a high‐iron diet than wild‐type mice. Ferrous iron (Fe²⁺) triggers ferroptosis via Fenton reactions and ROS accumulation. We further find that a rhodamine‐based "turn‐on" fluorescent probe(probe1) is suitable for the in vivo detection of Fe²⁺. Probe1 displays high selectivity towards Fe²⁺, and exhibits a stable response for Fe²⁺ with a concentration of 20 μM in tissue. Our data thus show that PPARα activation alleviates iron overload‐induced ferroptosis in mouse livers through Gpx4 and TRF, suggesting that PPARα may be a promising therapeutic target for drug discovery in ferroptosis‐related tissue injuries. Moreover, we identified a fluorescent probe that specifically labels ferrous ions and can be used to monitor Fe²⁺ in vivo.     

老年心肌梗死患者PCI术后心率变异性的变化及丹参滴丸的临床疗效研究

目的:探究老年心肌梗死患者经皮冠状动脉介入治疗(PCI)术后心率变异性的变化及实施PCI治疗后给予丹参滴丸的临床疗效。方法:收集2015年3月到2016年3月来我院就诊的老年急性心肌梗死患者56例,根据随机数字表法分为试验组及对照组,各28例,对所有患者实施PCI术,术后对照组使用基础药物治疗,试验组使用基础药物治疗联合复方丹参滴丸。比较PCI治疗前后心率变异性的变化及两组患者的心功能。结果:PCI术后,患者测定指标SDNN、SDNN Index及SDANN相对于术前均有升高(P0.05);频域分析指标HF及LF相对于术前均升高,LF/HF比值降低(P0.05)。治疗结束后,两组患者LVEF、SV及CI均明显升高,LVEDD明显降低(P0.05),与对照组相比,试验组患者LVEF、SV及CI较高,LVEDD较低(P0.05)。结论:PCI术能够改善老年心肌梗死患者心率变异性,而复方丹参滴丸对于PCI术后老年心肌梗死患者心功能指标均有明显改善,临床疗效较好。     

Space‐for‐time is not necessarily a substitution when monitoring the distribution of pelagic fishes in the San Francisco Bay‐Delta

Occupancy models are often used to analyze long‐term monitoring data to better understand how and why species redistribute across dynamic landscapes while accounting for incomplete capture. However, this approach requires replicate detection/non‐detection data at a sample unit and many long‐term monitoring programs lack temporal replicate surveys. In such cases, it has been suggested that surveying subunits within a larger sample unit may be an efficient substitution (i.e., space‐for‐time substitution). Still, the efficacy of fitting occupancy models using a space‐for‐time substitution has not been fully explored and is likely context dependent. Herein, we fit occupancy models to Delta Smelt (Hypomesus transpacificus) and Longfin Smelt (Spirinchus thaleichthys) catch data collected by two different monitoring programs that use the same sampling gear in the San Francisco Bay‐Delta, USA. We demonstrate how our inferences concerning the distribution of these species changes when using a space‐for‐time substitution. Specifically, we found the probability that a sample unit was occupied was much greater when using a space‐for‐time substitution, presumably due to the change in the spatial scale of our inferences. Furthermore, we observed that as the spatial scale of our inferences increased, our ability to detect environmental effects on system dynamics was obscured, which we suspect is related to the tradeoffs associated with spatial grain and extent. Overall, our findings highlight the importance of considering how the unique characteristics of monitoring programs influences inferences, which has broad implications for how to appropriately leverage existing long‐term monitoring data to understand the distribution of species.     

Aneuploid senescent cells activate NF‐κB to promote their immune clearance by NK cells

The immune system plays a major role in the protection against cancer. Identifying and characterizing the pathways mediating this immune surveillance are thus critical for understanding how cancer cells are recognized and eliminated. Aneuploidy is a hallmark of cancer, and we previously found that untransformed cells that had undergone senescence due to highly abnormal karyotypes are eliminated by natural killer (NK) cells in vitro. However, the mechanisms underlying this process remained elusive. Here, using an in vitro NK cell killing system, we show that non‐cell‐autonomous mechanisms in aneuploid cells predominantly mediate their clearance by NK cells. Our data indicate that in untransformed aneuploid cells, NF‐κB signaling upregulation is central to elicit this immune response. Inactivating NF‐κB abolishes NK cell‐mediated clearance of untransformed aneuploid cells. In cancer cell lines, NF‐κB upregulation also correlates with the degree of aneuploidy. However, such upregulation in cancer cells is not sufficient to trigger NK cell‐mediated clearance, suggesting that additional mechanisms might be at play during cancer evolution to counteract NF‐κB‐mediated immunogenicity.     

Genotyping validates the efficacy of photographic identification in a capture‐mark‐recapture study based on the head scale patterns of the prairie lizard (Sceloporus consobrinus)

Population studies often incorporate capture‐mark‐recapture (CMR) techniques to gather information on long‐term biological and demographic characteristics. A fundamental requirement for CMR studies is that an individual must be uniquely and permanently marked to ensure reliable reidentification throughout its lifespan. Photographic identification involving automated photographic identification software has become a popular and efficient noninvasive method for identifying individuals based on natural markings. However, few studies have (a) robustly assessed the performance of automated programs by using a double‐marking system or (b) determined their efficacy for long‐term studies by incorporating multi‐year data. Here, we evaluated the performance of the program Interactive Individual Identification System (I³S) by cross‐validating photographic identifications based on the head scale pattern of the prairie lizard (Sceloporus consobrinus) with individual microsatellite genotyping (N = 863). Further, we assessed the efficacy of the program to identify individuals over time by comparing error rates between within‐year and between‐year recaptures. Recaptured lizards were correctly identified by I³S in 94.1% of cases. We estimated a false rejection rate (FRR) of 5.9% and a false acceptance rate (FAR) of 0%. By using I³S, we correctly identified 97.8% of within‐year recaptures (FRR = 2.2%; FAR = 0%) and 91.1% of between‐year recaptures (FRR = 8.9%; FAR = 0%). Misidentifications were primarily due to poor photograph quality (N = 4). However, two misidentifications were caused by indistinct scale configuration due to scale damage (N = 1) and ontogenetic changes in head scalation between capture events (N = 1). We conclude that automated photographic identification based on head scale patterns is a reliable and accurate method for identifying individuals over time. Because many lizard or reptilian species possess variable head squamation, this method has potential for successful application in many species.     

MiR‐103‐3p targets the m6A methyltransferase METTL14 to inhibit osteoblastic bone formation

Impaired osteoblast function is involved in osteoporosis, and microRNA (miRNA) dysregulation may cause abnormal osteoblast osteogenic activity. However, the influence of miRNA on osteoblast activity and the underlying mechanisms remain elusive. In this study, miR‐103‐3p was found to be negatively correlated with bone formation in bone specimens from elderly women with fractures and ovariectomized (OVX) mice. Additionally, miR‐103‐3p directly targeted Mettl14 to inhibit osteoblast activity, and METTL14‐dependent N⁶‐methyladenosine (m⁶A) methylation inhibited miR‐103‐3p processing by the microprocessor protein DGCR8 and promoted osteoblast activity. Moreover, miR‐103‐3p inhibited bone formation in vivo, and therapeutic inhibition of miR‐103‐3p counteracted the decreased bone formation in OVX mice. Further, METTL14 was negatively correlated with miR‐103‐3p but positively correlated with bone formation in bone specimens from elderly women with fractures and OVX mice. Collectively, our results highlight the critical roles of the miR‐103‐3p/METTL14/m⁶A signaling axis in osteoblast activity, identifying this axis as a potential target for ameliorating osteoporosis.     

PECAM‐1 supports leukocyte diapedesis by tension‐dependent dephosphorylation of VE‐cadherin

Leukocyte extravasation is an essential step during the immune response and requires the destabilization of endothelial junctions. We have shown previously that this process depends in vivo on the dephosphorylation of VE‐cadherin‐Y731. Here, we reveal the underlying mechanism. Leukocyte‐induced stimulation of PECAM‐1 triggers dissociation of the phosphatase SHP2 which then directly targets VE‐cadherin‐Y731. The binding site of PECAM‐1 for SHP2 is needed for VE‐cadherin dephosphorylation and subsequent endocytosis. Importantly, the contribution of PECAM‐1 to leukocyte diapedesis in vitro and in vivo was strictly dependent on the presence of Y731 of VE‐cadherin. In addition to SHP2, dephosphorylation of Y731 required Ca²⁺‐signaling, non‐muscle myosin II activation, and endothelial cell tension. Since we found that β‐catenin/plakoglobin mask VE‐cadherin‐Y731 and leukocyte docking to endothelial cells exert force on the VE‐cadherin–catenin complex, we propose that leukocytes destabilize junctions by PECAM‐1‐SHP2‐triggered dephosphorylation of VE‐cadherin‐Y731 which becomes accessible by actomyosin‐mediated mechanical force exerted on the VE‐cadherin–catenin complex.     

Modification of the N‐terminal FWKG−αH1 element of potyviral HC‐Pro affects its multiple functions and generates effective attenuated mutants for cross‐protection

Control of plant viruses by cross‐protection is limited by the availability of effective protective strains. Incorporation of an NIa‐protease processing site in the extreme N‐terminal region of the helper component protease (HC‐Pro) of turnip mosaic virus (TuMV) resulted in a mutant virus TuHN^DI that induced highly attenuated symptoms. Recombination analysis verified that two variations, F7I mutation and amino acid 7‐upstream‐deletion, in HC‐Pro co‐determined TuHN^DI attenuation. TuHN^DI provided complete protection to Nicotiana benthamiana and Brassica campestris subsp. chinensis plants against infection by the severe parental strain. Aphid transmission tests revealed that TuHN^DI was not aphid‐transmissible. An RNA silencing suppression (RSS) assay by agroinfiltration suggested the RSS‐defective nature of the mutant HC‐Pro. In the context (amino acids 3–17) encompassing the two variations of HC‐Pro, we uncovered an FWKG−α‐helix 1 (αH1) element that influenced the functions of aphid transmission and RSS, whose motifs were located far downstream. We further demonstrated that HC‐Pro F7 was a critical residue on αH1 for HC‐Pro functions and that reinstating αH1 in the RSS‐defective HC‐Pro of TuHN^DI restored the protein''s RSS function. Yeast two‐hybrid and bimolecular fluorescence complementation assays indicated the FWKG−αH1 element as an integral part of the HC‐Pro self‐interaction domain. The possibility of regulation of the mechanistically independent functions of RSS and aphid transmission by the FWKG−αH1 element is discussed. Extension of TuMV HC‐Pro FWKG−αH1 variations to another potyvirus, zucchini yellow mosaic virus, also generated nonaphid‐transmissible cross‐protective mutant viruses. Hence, the modification of the FWKG−αH1 element can generate effective attenuated viruses for the control of potyviruses by cross‐protection.     

IFN‐γ+IL‐17+Th17 cells regulate fibrosis through secreting IL‐21 in systemic scleroderma

This study aimed to explore the function of IFN‐γ⁺IL‐17⁺Th17 cells on fibrosis in systemic scleroderma (SSc). Blood and skin samples were collected from 20 SSc cases and 10 healthy individuals. The percentage of IFN‐γ⁺IL‐17⁺Th17 cells was detected using flow cytometry. The in vitro induction of IFN‐γ⁺IL‐17⁺Th17 cells was performed adopting PHA and rIL‐12. Gene expression was detected via quantitative real‐time polymerase chain reaction (qRT‐PCR), whereas western blot analysis was adopted for protein analysis. The distribution of IFN‐γ⁺IL‐17⁺Th17 cells was significantly increased in SSc cases and positively correlated with SSc stages (P = .031), disease duration (P = .016), activity (P = .025) and skin scores (P < .001). In vitro, IFN‐γ⁺IL‐17⁺Th17 cells could promote the expressions of α‐SMA and COL1A1, revealing increased fibroblasts’ proliferation and enhanced collagen‐secreting capacity. In addition, IL‐21 expression was significantly increased in co‐culture medium of IFN‐γ⁺IL‐17⁺Th17 cells and fibroblasts (P < .001). IL‐21 neutralizer treatment resulted in the down‐regulation of α‐SMA and COL1A1. IL‐21 was confirmed as an effector of IFN‐γ⁺IL‐17⁺Th17 cells in fibrosis process. The distribution of IFN‐γ⁺IL‐17⁺Th17 cells was significantly increased in SSc cases and positively correlated with disease activity. IFN‐γ⁺IL‐17⁺Th17 cells could promote fibroblast proliferation and enhance collagen‐secreting ability via producing IL‐21, thus contributing to fibrosis in SSc.     

Dynamics of NK,CD8 and Tfh cell mediated the production of cytokines and antiviral antibodies in Chinese patients with moderate COVID‐19

Recent studies have demonstrated a marked decrease in peripheral lymphocyte levels in patients with coronavirus disease 2019 (COVID‐19) caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2). Few studies have focused on the changes of NK, T‐ and B‐cell subsets, inflammatory cytokines and virus‐specific antibodies in patients with moderate COVID‐19. A total of 11 RT‐PCR‐confirmed convalescent patients with COVID‐19 and 11 patients with non‐SARS‐CoV‐2 pneumonia (control patients) were enrolled in this study. NK, CD8⁺ T, CD4⁺ T, Tfh‐like and B‐cell subsets were analysed using flow cytometry. Cytokines and SARS‐CoV‐2‐specific antibodies were analysed using an electrochemiluminescence immunoassay. NK cell counts were significantly higher in patients with COVID‐19 than in control patients (P = 0.017). Effector memory CD8⁺ T‐cell counts significantly increased in patients with COVID‐19 during a convalescent period of 1 week (P = 0.041). TIM‐3⁺ Tfh‐like cell and CD226⁺ Tfh‐like cell counts significantly increased (P = 0.027) and decreased (P = 0.022), respectively, during the same period. Moreover, ICOS⁺ Tfh‐like cell counts tended to decrease (P = 0.074). No abnormal increase in cytokine levels was observed. The high expression of NK cells is important in innate immune response against SARS‐CoV‐2. The increase in effector memory CD8⁺ T‐cell counts, the up‐regulation of inhibitory molecules and the down‐regulation of active molecules on CD4⁺ T cells and Tfh‐like cells in patients with COVID‐19 would benefit the maintenance of balanced cellular and humoural immune responses, may prevent the development of severe cases and contribute to the recovery of patients with COVID‐19.     

Camera trap reveals the co‐occurrence patterns of two sympatric muntjac species in southern Anhui Province,China: No spatial segregation

The competitive relationship and coexistence pattern among close related species have long been one of the hot issues in ecological research. Interspecies interactions can exert important influences on the local distribution of rare species. Black muntjac Muntiacus crinifrons is an endemic species to eastern China, currently restricted to limited regions. In contrast, Chinese muntjac Muntiacus reevesi is the most common and widespread deer in southern China. Both species co‐occur in southern Anhui and western Zhejiang Province. Little is known about the interaction of these two sympatric‐related species. In this study, to investigate the site use determinants and co‐occurrence pattern of the two sympatric muntjac species, we conducted a camera trap survey across about 250 km² in mountainous area of southern Anhui Province, China. We adopted a multistep approach to incorporate habitat preferences while modeling occupancy and detection. We found that the two species did not separate along elevation gradient (range from 400 m to 1,400 m) as described in previous studies. Results of single‐species occupancy models indicated that elevation had positive effects on the site use of both species, while slope had an opposite influence on their site use. Positive effects of elevation on the site use implied that both species try to avoid human interference at low elevations. Significant negative effect of slope on the site use of black muntjac suggested that the species prefer habitat with gentle slope and avoided steep. Co‐occurrence models and species interaction factors provided evidence that the two muntjac species had an independent occupancy (ψ ^{BM CM} = ψ ^{BM cm}, SIF = 1) and exhibited a positive species interaction in detection probability (p ^BM < r ^{BM CM}). Combined with the results of previous studies, we suggested that it was fine differentiation in microhabitats and food resources utilization rather spatial or temporal segregation that allowed the two species co‐occurrence. The site use determinants revealed in our study would be useful for the habitat conservation and restoration for the rare black muntjac, and the co‐occurrence pattern of the two sympatric muntjac species could provide useful information for deep understanding of the coexistence mechanism among forest‐dwelling ungulates.     

DJ‐1 depletion prevents immunoaging in T‐cell compartments

Decline in immune function during aging increases susceptibility to different aging‐related diseases. However, the underlying molecular mechanisms, especially the genetic factors contributing to imbalance of naïve/memory T‐cell subpopulations, still remain largely elusive. Here, we show that loss of DJ‐1 encoded by PARK7/DJ‐1, causing early‐onset familial Parkinson’s disease (PD), unexpectedly diminished signs of immunoaging in T‐cell compartments of both human and mice. Compared with two gender‐matched unaffected siblings of similar ages, the index PD patient with DJ‐1 deficiency showed a decline in many critical immunoaging features, including almost doubled non‐senescent T cells. The observation was further consolidated by the results in 45‐week‐old DJ‐1 knockout mice. Our data demonstrated that DJ‐1 regulates several immunoaging features via hematopoietic‐intrinsic and naïve‐CD8‐intrinsic mechanisms. Mechanistically, DJ‐1 depletion reduced oxidative phosphorylation (OXPHOS) and impaired TCR sensitivity in naïve CD8 T cells at a young age, accumulatively leading to a reduced aging process in T‐cell compartments in older mice. Our finding suggests an unrecognized critical role of DJ‐1 in regulating immunoaging, discovering a potent target to interfere with immunoaging‐ and aging‐associated diseases.     

Dietary cardenolides enhance growth and change the direction of the fecundity‐longevity trade‐off in milkweed bugs (Heteroptera: Lygaeinae)

Sequestration, that is, the accumulation of plant toxins into body tissues for defense, was predicted to incur physiological costs and may require resistance traits different from those of non‐sequestering insects. Alternatively, sequestering species could experience a cost in the absence of toxins due to selection on physiological homeostasis under permanent exposure of sequestered toxins in body tissues. Milkweed bugs (Heteroptera: Lygaeinae) sequester high amounts of plant‐derived cardenolides. Although being potent inhibitors of the ubiquitous animal enzyme Na⁺/K⁺‐ATPase, milkweed bugs can tolerate cardenolides by means of resistant Na⁺/K⁺‐ATPases. Both adaptations, resistance and sequestration, are ancestral traits of the Lygaeinae. Using four milkweed bug species (Heteroptera: Lygaeidae: Lygaeinae) and the related European firebug (Heteroptera: Pyrrhocoridae: Pyrrhocoris apterus) showing different combinations of the traits “cardenolide resistance” and “cardenolide sequestration,” we tested how the two traits affect larval growth upon exposure to dietary cardenolides in an artificial diet system. While cardenolides impaired the growth of P. apterus nymphs neither possessing a resistant Na⁺/K⁺‐ATPase nor sequestering cardenolides, growth was not affected in the non‐sequestering milkweed bug Arocatus longiceps, which possesses a resistant Na⁺/K⁺‐ATPase. Remarkably, cardenolides increased growth in the sequestering dietary specialists Caenocoris nerii and Oncopeltus fasciatus but not in the sequestering dietary generalist Spilostethus pandurus, which all possess a resistant Na⁺/K⁺‐ATPase. We furthermore assessed the effect of dietary cardenolides on additional life history parameters, including developmental speed, longevity of adults, and reproductive success in O. fasciatus. Unexpectedly, nymphs under cardenolide exposure developed substantially faster and lived longer as adults. However, fecundity of adults was reduced when maintained on cardenolide‐containing diet for their entire lifetime but not when adults were transferred to non‐toxic sunflower seeds. We speculate that the resistant Na⁺/K⁺‐ATPase of milkweed bugs is selected for working optimally in a “toxic environment,” that is, when sequestered cardenolides are stored in the body.     

A novel camera trapping method for individually identifying pumas by facial features

Camera traps (CTs), used in conjunction with capture–mark–recapture analyses (CMR; photo‐CMR), are a valuable tool for estimating abundances of rare and elusive wildlife. However, a critical requirement of photo‐CMR is that individuals are identifiable in CT images (photo‐ID). Thus, photo‐CMR is generally limited to species with conspicuous pelage patterns (e.g., stripes or spots) using lateral‐view images from CTs stationed along travel paths. Pumas (Puma concolor) are an elusive species for which CTs are highly effective at collecting image data, but their suitability to photo‐ID is controversial due to their lack of pelage markings. For a wide range of taxa, facial features are useful for photo‐ID, but this method has generally been limited to images collected with traditional handheld cameras. Here, we evaluate the feasibility of using puma facial features for photo‐ID in a CT framework. We consider two issues: (1) the ability to capture puma facial images using CTs, and (2) whether facial images improve human ability to photo‐ID pumas. We tested a novel CT accessory that used light and sound to attract the attention of pumas, thereby collecting face images for use in photo‐ID. Face captures rates increased at CTs that included the accessory (n = 208, χ ² = 43.23, p ≤ .001). To evaluate if puma faces improve photo‐ID, we measured the inter‐rater agreement of 5 independent assessments of photo‐ID for 16 of our puma face capture events. Agreement was moderate to good (Fleiss’ kappa = 0.54, 95% CI = 0.48–0.60), and was 92.90% greater than a previously published kappa using conventional CT methods. This study is the first time that such a technique has been used for photo‐ID, and we believe a promising demonstration of how photo‐ID may be feasible for an elusive but unmarked species.