Antimicrobial peptide MPX alleviates the lethal attack of Escherichia coli in mice

Escherichia coli is an important zoonotic pathogen causing intestinal diseases. In recent years, due to the unreasonable use of antibiotics, the drug resistance of bacteria has been increasing, and the proportion of multi-drug resistant strains has also been rising, which directly threatens the health of animals and humans. The antimicrobial peptide MPX was isolated from wasp venom and had better antibacterial activity against Gram-positive and Gram-negative bacteria. Studies have found that MPX had better bactericidal activity against E. coli in vitro. However, whether MPX also has better bactericidal activity in mice is still unknown. This study found that E. coli infected mice lost appetite, diarrhea, and grouping together, while MPX treatment significantly alleviated these symptoms. The autopsy results found that the intestinal congestion, bleeding, thinning of the intestinal wall, yellow viscous fluid in the intestinal cavity, congestion of the lungs, necrosis in the liver, congestion, and bleeding of the spleen, and MPX treatment effectively relieved the above symptoms. The qRT-PCR results found that MPX could increase the mRNA expression of the antibacterial protein TFF3 in the jejunum and colon and reduce the expression of the antibacterial protein Remlβ and REG3γ in the jejunum and colon. H&E staining results further found that MPX could alleviate the pathological damage of mouse intestines and organs caused by E. coli infection. The above results show that MPX has good bactericidal activity against E. coli infection in mice, providing an essential reference for screening drugs for the clinical treatment of E. coli infection

The function of antimicrobial peptide MPX on the apoptosis and barrier of IPEC-J2 cells

The porcine intestinal epithelial cell line IPEC-J2 cells, which were isolated from neonatal piglet mid-jejunum, the main components of the intestinal epithelium and play an important role in the intestine. Escherichia coli is an important cause of diarrhea in human and animal. E.coli infections are the leading cause of travelers' diarrhea and a major cause of diarrhea in developing nations, where it can be life-threatening among children. The aim of this study is to explore MPX against E. coli to inhibit IPEC-J2 cells apoptosis and enhance cell barrier. In this study, scanning electron microscopy results found that E. coli infection caused cell apoptosis and destroyed cell membranes of IPEC-J2 cell. MPX effectively alleviated apoptosis of IPEC-J2 cells. The laser confocal results further found that MPX prevented cell apoptosis by inhibiting caspase-3 and caspase-9 activation. In addition, it was found that MPX regulated the expression of tight junction proteins ZO-1, Occludin, and Claudin-1 in IPEC-J2 cells and is closely related to Rac1 by adding a Rac1 inhibitor. The results of adhesion and invasion experiments further found that MPX inhibited bacterial adhesion and invasion through Rac1. The above results indicated that MPX has better function in inhibiting IPEC-J2 cells apoptosis and enhancing cell barrier

Palynological investigation of Holocene climatic and oceanic variability in South Africa and the southern Benguela upwelling system

South Africa is very sensitive to climate change, because it is located between two atmospheric systems (subtropical and warm-temperate systems) and two oceanic systems (Benguela Current and Agulhas Current). Presently, the seasonal changes of atmospheric and oceanic systems induce a pronounced rainfall seasonality comprised of three different rainfall zones (summer rainfall zone, SRZ; year-round rainfall zone, YRZ and winter rainfall zone, WRZ) over South Africa. However, the seasonality development during the Holocene in South Africa is poorly understood and the driving forces of the climate change are debated. Therefore, this study aims to provide a detailed reconstruction of Holocene climate and vegetation variability of South Africa, palaeoceanographic changes in the southern Benguela upwelling system as well as the land-ocean linkages. In the first part of this thesis, the spatial distribution of pollen in marine surface sediments was investigated based on a transect of 12 marine surface sediment samples retrieved from north (29.12AAAAAAAdegreeS) to south (32.50AAAAAAAdegreeS) of the Namaqualand mudbelt off western South Africa. The distinct pollen spectra reflect vegetation communities on the adjacent continent with a marked north-south gradient of pollen concentration. The distribution of specific pollen taxa suggests that the Orange River is a major contribution of pollen to the northern mudbelt declining southwards. Whereas the seasonal inputs of pollen from offshore berg winds and local ephemeral Namaqualand rivers have a great contribution to the central mudbelt. In the southern mudbelt, the dominated Fynbos elements indicate a main pollen source from the Fynbos vegetation in the southwestern Cape of South Africa. The approach in the first part of this thesis allows for climate reconstructions of the SRZ and WRZ using specific pollen taxa from a single marine archive. Therefore, in the second part of this thesis, the Holocene vegetation and climate variability in South Africa was reconstructed using pollen and microcharcoal records of two marine core sites GeoB8331 and GeoB8323 from the Namaqualand mudbelt offshore of the west coast of South Africa covering the last 9900 and 2200 years, respectively. Three different climate periods were described with apparently contrasting climate developments between the SRZ and WRZ: during the early Holocene (9900-7800 cal. yr BP), a minimum of grass pollen suggests lower summer rainfall in the SRZ, while relatively wet conditions in the WRZ were indicated by the initial presence of Renosterveld vegetation. During the middle Holocene (7800-2400 cal. yr BP), a maximum in grass pollen suggests an expansion of rather moist savanna/grassland. This is probably associated with higher summer rainfall in the SRZ resulting from increased austral summer insolation. In the WRZ, a decline of Fynbos vegetation accompanied by an expansion of Succulent Karoo vegetation indicate warmer and drier conditions, which possibly suggests a southward shift of the southern westerlies. Comparing the results of the two sites for the last 2200 years show a more stable climate in the WRZ than in the SRZ. In addition, the a Little Ice Agea (LIA) event (ca. 700-200 cal. yr BP) was detected with colder and drier conditions in the SRZ but colder and wetter conditions in the WRZ. To assess the land-sea linkages in this region, in the third part of this thesis, the Holocene palaeoceanographic and palaeoenvironmental changes in the southern Benguela upwelling system was investigated based on the organic-walled dinoflagellate cyst analysis of 12 marine surface sediment samples and gravity core GeoB8331-4 from the Namaqualand mudbelt offshore of the west coast of South Africa. The results were compared with pollen and geochemical records from the same samples. Three main phases were identified with significantly distinct oceanographic conditions during the Holocene: during the early Holocene (9900-8400 cal. yr BP), warm and stratified conditions were indicated by high percentages of autotrophic taxa suggesting reduced upwelling likely due to a northward shift of the southern westerlies. In contrast, during the middle Holocene (8400-3100 cal. yr BP), cool and nutrient-rich waters with active upwelling were indicated by a strong increase in heterotrophic taxa at the expense of autotrophic taxa. This is probably caused by a southward shift of the southern westerlies. During the late Holocene (3100 cal. yr BP to modern), strong river discharge with high nutrient supply between 3100-640 cal. yr BP was implied by high percentages of Brigantedinium spp. and other fluvial-related taxa such as Protoperidinium americanum and Lejeunecysta oliva

Antimicrobial peptides as novel alternatives to antibiotics

In recent years, due to the unreasonable use of antibiotics, bacterial resistance has increased, posing a huge threat to human health and the healthy development of the swine industry. Therefore, it is an urgent to look for antibiotic alternatives. Antimicrobial peptides are a class of small molecule peptides, which are the body's first line of defense against the invasion of pathogenic microorganisms. They have small molecular weight, good water solubility, and not easy to produce drug resistance. Therefore, antimicrobial peptides are considered as one of the best alternatives to antibiotics. This review focuses on the mechanism of action of antimicrobial peptides, especially improve performance, improve intestinal inflammation and nutrient digestibility, regulate the intestinal microbiota and enhance the immune function of swine. Overall, AMPs have great potential for application  as an alternative to antibiotics in swine industry

Circular Accessible Depth: A Robust Traversability Representation for UGV Navigation

In this paper, we present the Circular Accessible Depth (CAD), a robust traversability representation for an unmanned ground vehicle (UGV) to learn traversability in various scenarios containing irregular obstacles. To predict CAD, we propose a neural network, namely CADNet, with an attention-based multi-frame point cloud fusion module, Stability-Attention Module (SAM), to encode the spatial features from point clouds captured by LiDAR. CAD is designed based on the polar coordinate system and focuses on predicting the border of traversable area. Since it encodes the spatial information of the surrounding environment, which enables a semi-supervised learning for the CADNet, and thus desirably avoids annotating a large amount of data. Extensive experiments demonstrate that CAD outperforms baselines in terms of robustness and precision. We also implement our method on a real UGV and show that it performs well in real-world scenarios.Comment: 13 pages, 8 figure

Vibration Damping of Carbon Nanotube Assembly Materials

Vibration reduction is of great importance in various engineering applications, and a material that exhibits good vibration damping along with high strength and modulus has become more and more vital. Owing to the superior mechanical property of carbon nanotube (CNT), new types of vibration damping material can be developed. This paper presents recent advancements, including our progresses, in the development of high-damping macroscopic CNT assembly materials, such as forests, gels, films, and fibers. In these assemblies, structural deformation of CNTs, zipping and unzipping at CNT connection nodes, strengthening and welding of the nodes, and sliding between CNTs or CNT bundles are playing important roles in determining the viscoelasticity, and elasticity as well. Towards the damping enhancement, strategies for micro-structure and interface design are also discussed

Differences of Heart Rate Variability Between Happiness and Sadness Emotion States: A Pilot Study

This pilot study investigated the differences of heart rate variability (HRV) indices between two opposite emotion states: happiness and sadness, to reveal the differences of autonomic nervous system activity under different emotional states. Forty-eight healthy volunteers were enrolled for this study. Electrocardiography (ECG) signals were recorded under both emotion states with a random measurement order (first happiness emotion measurement then sadness or reverse). RR interval (RRI) time series were extracted from ECGs and multiple HRV indices, including time-domain (MEAN, SDNN, RMSSD and PNN50), frequency-domain (LFn, HFn and LF/HF) and nonlinear indices (SampEn and FuzzyMEn) were calculated. In addition, the effects of heart rate (HR) and mean artery pressure (MAP) on the aforementioned HRV indices were analyzed for both emotion states. The results showed that experimental order had no significant effect on all HRV indices from both happiness and sadness emotions (all P > 0.05). The key result was that among all nine HRV indices, six indices were identified having significant differences between happiness and sadness emotion states: MEAN (P = 0.028), SDNN (P = 0.002), three frequency-domain indices (all P < 0.0001) and FuzzyMEn (P = 0.047), whereas RMSSD, PNN50 and SampEn had no significant differences between the two emotion states. All indices, except for SampEn, had significant positive correlations (all P < 0.01) for the two emotion states. Four time-domain indices decreased with the increase of HR (all P < 0.01), while frequency-domain and nonlinear indices demonstrated no HR-related changes for each emotional state. In addition, all indices (time-domain, frequency-domain and nonlinear) showed no MAP-related changes. It concluded that HRV indices showed significant differences between happiness and sadness emotion states and the findings could help to better understand the inherent differences of cardiovascular time series between different emotion states in clinical practice

MiR-214 promotes renal fibrosis in diabetic nephropathy via targeting SOCS1

Purpose: To elucidate how miR-214 regulates the pathogenesis of diabetic nephropathy (DN). Methods: The extent of fibrosis in DN mice kidneys was examined using Masson’s staining. Quantitative polymerase chain reaction (qPCR) was used to determine the levels of miR-214. Dual luciferase reporter assay was used to identify the target of miR-214. The expression of fibrosis marker proteins of high glucose-stimulated NRK-52E cells transfected with miR-214 was determined using western blotting. Results: Fibrosis in renal tissue of DN mice was significantly increased and miR-214 was upregulated (p &lt; 0.001). Suppressor of cytokine signaling 1 protein (SOCS1) was the target gene of miR-214, and overexpression of miR-214 promoted fibrosis (p &lt; 0.05, p &lt; 0.001). On the other hand, overexpression of SOCS1 inhibited this process, indicating that miR-214 promoted fibrosis via targeting SOCS1 (p &lt; 0.001). Finally, inhibition of miR-214 c ameliorated renal fibrosis in DN mice (p &lt; 0.01, p &lt; 0.001). Conclusions: MiR-214 is upregulated in db/db DN mice kidney tissue; miR-214 regulates renal fibrosis in DN mice by targeting SOCS1

The nuclear factor-κB inhibitor pyrrolidine dithiocarbamate reduces polyinosinic-polycytidilic acid-induced immune response in pregnant rats and the behavioral defects of their adult offspring

<p>Abstract</p> <p>Background</p> <p>Epidemiological studies have indicated that maternal infection during pregnancy may lead to a higher incidence of schizophrenia in the offspring. It is assumed that the maternal infection increases the immune response, leading to neurodevelopmental disorders in the offspring. Maternal polyinosinic-polycytidilic acid (PolyI:C) treatment induces a wide range of characteristics in the offspring mimicking some schizophrenia symptoms in humans. These observations are consistent with the neurodevelopmental hypothesis of schizophrenia.</p> <p>Methods</p> <p>We examined whether suppression of the maternal immune response could prevent neurodevelopmental disorders in adult offspring. PolyI:C or saline was administered to early pregnant rats to mimic maternal infection, and the maternal immune response represented by tumor necrosis factor alpha (TNF-α) and interleukin-10 (IL-10) levels was determined by enzyme-linked immunosorbent assays (ELISA). The NF-κB inhibitor pyrrolidine dithiocarbamate (PDTC) was used to suppress the maternal immune response. Neurodevelopmental disorders in adult offspring were examined by prepulse inhibition (PPI), passive avoidance, and active avoidance tests.</p> <p>Results</p> <p>PolyI:C administration to early pregnant rats led to elevated serum cytokine levels as shown by massive increases in serum TNF-α and IL-10 levels. The adult offspring showed defects in prepulse inhibition, and passive avoidance and active avoidance tests. PDTC intervention in early pregnant rats suppressed cytokine increases and reduced the severity of neurodevelopmental defects in adult offspring.</p> <p>Conclusions</p> <p>Our findings suggest that PDTC can suppress the maternal immune response induced by PolyI:C and partially prevent neurodevelopmental disorders of adult offspring.</p