► A novel superfamily of cysteine-rich peptides (referred to as HsVx1 family) was identified from scorpions. ► The genomic organization of HsVx1 markedly differs from those of other peptides from ...scorpions. ► The evolution of the HsVx1 superfamily genes were dominated by intron sliding and intron loss. ► Intron in the 3′-terminal region was preferentially lost, whereas that in the 5′-terminal region preferentially slid. ► The reverse complementary sequence of the third intron of an HsVx1-like peptide gene also codes for a different HsVx1-like peptide.
The full-length cDNA sequences of two novel cysteine-rich peptides (referred to as HsVx1 and MmKTx1) were obtained from scorpions. The two peptides represent a novel class of cysteine-rich peptides with a unique cysteine pattern. The genomic sequence of HsVx1 is composed of three exons interrupted by two introns that are localized in the mature peptide encoding region and inserted in phase 1 and phase 2, respectively. Such a genomic organization markedly differs from those of other peptides from scorpions described previously. Genome-wide search for the orthologs of HsVx1 identified 59 novel cysteine-rich peptides from arthropods. These peptides share a consistent cysteine pattern with HsVx1. Genomic comparison revealed extensive intron length differences and intronic number and position polymorphisms among the genes of these peptides. Further analysis identified 30 cases of intron sliding, 1 case of intron gain and 22 cases of intron loss occurred with the genes of the HsVx1 and HsVx1-like peptides. It is interesting to see that three HsVx1-like peptides XP_001658928, XP_001658929 and XP_001658930 were derived from a single gene (XP gene): the former two were generated from alternative splicing; the third one was encoded by a DNA region in the reverse complementary strand of the third intron of the XP gene. These findings strongly suggest that the genes of these cysteine-rich peptides were evolved by intron sliding, intron gain/loss, gene recombination and alternative splicing events in response to selective forces without changing their cysteine pattern. The evolution of these genes is dominated by intron sliding and intron loss.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
•Three novel antimicrobial peptides (Pantinin-1, Pantinin-2 and Pantinin-3) were identified from Pandinus imperator.•The three peptides have relatively strong antimicrobial activities against ...Gram-positive bacteria.•Pantinin-3 has great potential to be applied in the treatment of VRE infections.•We found that hydrophobicity of the hydrophilic region significantly affects the activity of antimicrobial peptides.
Three novel cysteine-free venom peptides, which were referred to as Pantinin-1, Pantinin-2 and Pantinin-3, respectively, have been identified from the scorpion Pandinus imperator by cDNA cloning strategy. The precursor of each peptide consists of a signal peptide, a mature peptide with no disulfide bridges, and an acidic propeptide with a typical processing signal. Each of the three peptides is an α-helical, cationic and amphipathic molecule with 13 or 14 amino acid residues. Their amino acid sequences are homologous to those of some 13-mer antimicrobial peptides isolated from scorpions. Antimicrobial assay showed that all the three peptides possess relatively strong activities against Gram-positive bacteria and a fungus, but have very weak antimicrobial activities against Gram-negative bacteria. Toxicity assay showed that the three peptides exhibit very low or mild hemolytic activities against human red blood cells. It is interesting to see that Pantinin-3 is able to potently inhibit the growth of vancomycin-resistant Enterococcus (VRE) S13, a pathogen that can cause a number of human infections; this suggests that Pantinin-3 has great potential to be applied in the treatment of VRE infections. Our findings gain new insights into the structure/function relationships of the small linear cationic antimicrobial peptides from scorpions, and provide new templates for designing of antimicrobial agents targeting antibiotic-resistant pathogenic bacteria.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
3.
Pontibacter yuliensis sp. nov., isolated from soil Cao, Hanjun; Nie, Yao; Zeng, Xian-Chun ...
International journal of systematic and evolutionary microbiology,
03/2014, Volume:
64, Issue:
Pt 3
Journal Article
Peer reviewed
A Gram-staining-negative, rod-shaped and pink bacterium was isolated from the soil of a Populus euphratica forest in the Taklamakan desert, Xinjiang, China. It was designated strain H9XT. A 16S rRNA ...gene sequence homology search indicated that the isolate was most closely related to the family Cytophagaceae. The 16S rRNA gene of strain H9XT displayed 94.2–96.3 % sequence identities to those of type strains of other species of the genus Pontibacter. It only possessed menaquinone-7. The major cellular fatty acids of the novel isolate were iso-C15 : 0, C16 : 1ω5c summed feature 3 (containing C16 : 1ω6c and/or C16 : 1ω7c) and summed feature 4 (comprising anteiso-C17 : 1 B and/or iso-C17 : 1 I). The major polar lipids were phosphatidylethanolamine, one unknown aminophospholipid, one unknown glycophospholipid and several unknown phospholipids. The DNA G+C content of this bacterium was 55.2 mol%. Based on the phenotypic and genotypic data presented, it can be concluded that this isolate represents a novel species of the genus Pontibacter, for which the name Pontibacter yuliensis sp. nov. is proposed. The type strain is H9XT ( = CCTCC AB 2013047T = KCTC 32396T).
•Three new cysteine-free peptides (Heterin-1, Heterin-2 and Spiniferin) were identified from the scorpion Heterometrus spinifer.•The genomic organizations of the three peptides are similar to those ...of the known cysteine-rich toxins from scorpions.•Heterin-1, Heterin-2 and Spiniferin have relatively strong, intermediate and weak antimicrobial activities, respectively.•Deletion of the random coiled KKD tail markedly changed the antimicrobial specificity and activity of Heterin-2.•For some bacteria, net charge on the polar face of Spiniferin is not important for its antimicrobial activity.
Three new cysteine-free venom peptides, which are referred to as Heterin-1, Heterin-2 and Spiniferin, respectively, were identified from the scorpion Heterometrus spinifer. Heterin-1, Heterin-2 and Spiniferin contain 43, 24 and 13 amino acid residues, respectively. Genomic analysis showed that the genomic organizations of the three peptides are consistent with those of the known Na+, K+ or Cl−-channel specific toxins from scorpions; this suggests that the genes of the cysteine-free and cysteine-rich peptides from scorpions were derived from a common ancestor. Antimicrobial assay demonstrated that Heterin-1 possesses potent activities against both Gram-positive and Gram-negative bacteria. Among the tested bacterial species, Heterin-1 is the most active against Bacillus megaterium and Micrococcus luteus with MICs of 4.0μM and 4.0μM, respectively. Heterin-2 is able to potently inhibit the growth of Gram-positive bacteria with MICs from 5.6μM to 30.0μM; however, it has weaker activities against the tested Gram-negative bacteria. It is interesting to see that deletion of the C-terminal random coiled tail (KKD) in Heterin-2 markedly changed the antimicrobial specificity and activity of the peptide. Spiniferin has very weak antimicrobial activities against both Gram-positive and Gram-negative bacteria. We found that introducing three net charges into the polar face of Spiniferin significantly increased its antimicrobial activity against the majority of the tested bacteria; however, in some instances, net charge on the polar face is not important for the antimicrobial activity of the peptide. These studies have expanded our understanding of the diversity, evolution and structure/function relationships of the cysteine-free peptides from scorpions.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
► A novel BmKBT-like peptide, BmKBy, was identified from Mesobuthus martensii Karsch. ► Both BmKBT and BmKBy possess potent toxicity in mammal, but weak toxicity in insect. ► Two genes, of which ...intron sizes differ in 5.8 folds, code for BmKBT, whereas one gene with an intron of 1312bp codes for BmKBy. ► The tremendous difference of the intron lengths of the BmKBT genes provides a mechanical basis for either constitutive expression or rapid generation of the toxic peptides in response to different signals.
The cDNA sequence encoding a novel BmKBT-like peptide (referred to as BmKBy) was cloned and sequenced from the scorpion Mesobuthus martensii Karsch. Functional analysis indicated that both BmKBT and BmKBy possess strong toxicity in mice, but very weak toxicity in cotton bollworm. Phylogenetic analysis showed that BmKBy and BmKBT represent evolutionary intermediates between the α- and β-toxins from scorpions. The genomic sequences of BmKBT and BmKBy were also obtained. It is interesting to see that two genes, which contain an intron of 225 and 1529bp, respectively, exactly code for the BmKBT peptide. One gene, which contains an intron of 1312bp, codes for BmKBy. Given that genes with long introns favor constitutive expression, whereas those with short introns are rapidly regulated in response to stimulations, the BmKBT_a and BmKBT_b genes provide a mechanical basis for either constitutive expression or rapid generation of the toxic peptides in response to different signals.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Time-varying mesh stiffness is one of the main excitation sources of a gear system, and it is also considered as an important factor for the vibration and noise of gears. Thus, this excitation is ...usually taken as an input into the gear dynamic model to obtain the system dynamic responses. However, the mesh stiffness of a gear pair is actually nonlinear with respect to the dynamic mesh force (DMF) that fluctuates during the operation of gears. Therefore, the dynamic model of gears with the quasi-static mesh stiffness calculated under a constant load is not accurate sufficiently. In this paper, a dynamic model of spur gear is established with considering the effect of the force-dependent time-varying mesh stiffness, backlash and profile deviation. Due to the nonlinear relationship between the mesh stiffness and the load for each tooth pair, it needs first to determine the load sharing among tooth pairs and then calculate the overall mesh stiffness of the gear pair. As the mesh stiffness and DMF are related, the mesh stiffness is no longer directly taken into the gear dynamic model as an input, but is jointly solved with the numerical integration process using the gear dynamic model. Finally, the dynamic responses predicted from the established gear dynamic model are compared with the experimental results for validation and compared with the traditional models to reveal their differences. The results indicate that the established dynamic model of spur gear transmission has a wider application range than the traditional models.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Metal–organic framework (MOF) nanosheets are a class of two-dimensional (2D) porous and crystalline materials that hold promise for catalysis and biodetection. Although 2D MOF nanosheets have been ...utilized for in vitro assays, ways of engineering them into diagnostic tools for live animals are much less explored. In this work, a series of MOF nanosheets are successfully engineered into a highly sensitive and selective diagnostic platform for in vivo monitoring of heparin (Hep) activity. The iron-porphyrin derivative is selected as a ligand to synthesize a series of archetypical MOF nanosheets with intrinsic heme-like catalytic sites, mimicking peroxidase. Hep-specific AG73 peptides as recognition motifs are physically adsorbed onto MOF nanosheets, blocking active sites from nonspecific substrate–catalyst interaction. Because of the highly specific interaction between Hep and AG73, the activity of AG73-MOF nanosheets is restored upon the binding of Hep, but not Hep analogues and other endogenous biomolecules. Furthermore, by taking advantages of biocompatibility and diagnostic property enabled by AG73-MOF nanosheets, the elimination process of Hep in live rats is quantitatively monitored by coupling with microdialysis technology. This work expands the biomedical applications of 2D MOF nanomaterials and provides access to a promising in vivo diagnostic platform.
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IJS, KILJ, NUK, PNG, UL, UM
Exosomal microRNAs (miRNAs) are emerging as attractive non-invasive and reliable biomarkers for disease diagnosis. In situ exosomal miRNA detection can avoid laborious and time-consuming exosome ...lysis, RNA extraction and effectively improve the accuracy. However, in situ exosomal miRNA detection is hampered by the low abundance of the targets and low permeability of the probes. Herein, an in situ exosomal miRNA sensing biochip based on multi-branched localized catalytic hairpin assembly (MLCHA) and photonic crystals (PCs) was proposed. The MLCHA probes could penetrate into the exosomes nondestructively due to its rigidity and generate amplified fluorescence signal upon recognizing the target miRNA. And then, the fluorescence signal was further enhanced by PCs to improve the sensitivity. The developed biosensor can not only detect exosomal miRNA in a concentration-dependent manner but also distinguish samples from cancer state and healthy state, which is potential for non-invasive clinical diagnostics.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Sludge treatment and disposal have become critical environmental issues in China. Electro-dewatering (ED) is an attractive technology for enhancing dewaterability and improving the sustainability of ...waste activated sludge (WAS) handling. However, electrically assisted mechanical dewatering processes consume more energy and the extracellular polymeric substance (EPS) dissolution caused by electrochemical reactions can lead to clogging of the filter cloth. Carbon-based materials (CBMs) such as activated carbon and graphite have electrical conductivity and well-developed pore structures which can adsorb the biopolymers. Therefore, addition of CBMs is expected to improve WAS electro-dewatering performance for fuel treatment by enhancing sludge conductivity and filterability. In this study, we evaluated the effects of the three carbon materials (AC-0, AC-5, and graphite) on sludge electro-dewatering behavior and the flammability of sludge cakes. The results showed that CBMs promote the performance of WAS electro-dewatering, and the promoting effect of the carbon materials on the sludge electro-dewatering is proportional to the electrical conductivity of the carbon material, and carbon materials can increase the electrophoretic mobility of sludge flocs and the electro-osmotic effect. Moreover, CBMs can adsorb the dissolved EPS, thus alleviate the plugging and filtration resistance of the filter medium. The addition of CBMs also decreases the energy consumption for water removal during the electro-dewatering process and improves the calorific value and sustainable combustion time of the sludge cake. Our approach can facilitate the resource utilization of the dewatered sludge cake in electro-dewatering processes.
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•CBMs enhanced the sludge electro-dewatering performance.•CBMs increased the electrophoretic mobility and electro-osmotic effects of sludge flocs.•CBMs can adsorb the dissolved EPS and promote sludge filterability.•CBMs can improve the calorific value of sludge cake.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
