Characteristics and Risk Assessments of Mercury Pollution Levels at Domestic Garbage Collection Points Distributed within the Main Urban Areas of Changchun City.

The mercury that is released from the centralized treatment of municipal solid waste is an important source of atmospheric mercury. We chose the main urban area of Changchun as a representative area. Environmental factors such as total mercury content, temperature, wind speed, and other factors were measured in samples from the trash cans of two types of collection points (trash cans and garbage stations), the topsoil under the selected trash cans, and the ambient air above the selected trash cans. The potential ecological risks of mercury pollution were evaluated. The results showed that the mercury content levels of all sample types in the refuse transfer station were higher than the garbage cans and there were no significant differences observed between soil surface mercury and garbage cans. The mercury content levels in the atmosphere and the surface soil at the garbage collection points were found to increase along the cascade relationship of the garbage collection. However, there were no correlations observed between the atmospheric mercury content levels and the surface soil mercury content levels with the attachments and the sum of the former two. There were no correlations observed between surface soil and the attachments, or among the attachments, surface soil, and the atmospheric mercury content levels. The mercury content levels in the attachments, surface soil, and atmosphere of the garbage collection points in the study area were negatively correlated with the loop lines. Meanwhile, the potential ecological risk indexes of the garbage cans and garbage stations were found to be high. The chronic non-carcinogenic risks of mercury to children and adults were determined to be very low. The risks of mercury to children were higher when compared with adults. The highest non-carcinogenic risks of mercury pollution were determined to be within the central area of Changchun.

Two families of antimicrobial peptides from wasp (Vespa magnifica) venom.

The hornet possesses highly toxic venom, which is rich in toxin, enzymes and biologically active peptides. Many bioactive substances were identified from wasp venom. Two families of antimicrobial peptides were purified and characterized from the venom of the wasp, Vespamagnifica (Smith). The primary structures of these peptides are homologous to those of chemotactic peptides and mastoparans isolated from other vespid venoms. They also share similarity to temporins which are amphibian antimicrobial peptides identified from the skin of the frog, Ranaboylii. These peptides show antimicrobial activities against bacteria and fungi. However, they show little hemolytic activity against human blood red cells.

Two antimicrobial peptides from skin secretions of Rana grahami.

Two antimicrobial peptides manifested a broad spectrum of antimicrobial activity against various microorganisms have been isolated from skin secretions of Rana grahami. These antimicrobial peptides were named grahamin 1 and grahamin 2. Their primary structures are GLLSGILGAGKNIVCGLSGLC and GLLSGILGAGKHIVCGLSGLC, respectively, determined by Edman degradation and mass spectrometry. They are structurally related to nigrocins identified from skin secretions of the dark-spotted frog, Rana nigromaculata. The cDNA clones encoding the precursor of grahamins were screened and sequenced from the skin cDNA library of R. grahami. The amino sequences deduced from the cDNA sequences match well with the results from Edman degradation. As other antimicrobial peptides from Rana species, grahamins contain a C-terminal loop region delineated by an intra-disulfide bridge named Rana box. Based on structural comparison of grahamin with other known antimicrobial peptides, grahamins could be classified into the family of antimicrobial peptides containing a single intra-disulfide bridge.

A Novel Toxin from Haplopelma lividum Selectively Inhibits the NaV1.8 Channel and Possesses Potent Analgesic Efficacy.

Spider venoms are a complex mixture of peptides with a large number of neurotoxins targeting ion channels. Although thousands of peptide toxins have been identified from venoms of numerous species of spiders, many unknown species urgently need to be investigated. In this study, a novel sodium channel inhibitor, µ-TRTX-Hl1a, was identified from the venom of Haplopelma lividum. It contained eight cysteines and formed a conserved cysteine pattern of ICK motif. µ-TRTX-Hl1a inhibited the TTX-resistant (TTX-r) sodium channel current rather than the TTX-sensitive (TTX-s) sodium channel current. Meanwhile, µ-TRTX-Hl1a selectively inhibited NaV1.8 with an IC50 value of 2.19 µM. Intraperitoneal injection of µ-TRTX-Hl1a dose-dependently reduced inflammatory and neuropathic pain in rodent models of formalin-induced paw licking, tail-flicking, acetic acid-induced writhing, and hot plate test. It showed a better analgesic effect than morphine in inflammatory pain and equipotent effect to morphine in neuropathic pain. These findings demonstrate that µ-TRTX-Hl1a might be a valuable tool for physiology studies on NaV1.8 and a promising lead molecule for pain therapeutics.

A Novel Myotoxin from the Venom of Trimeresurus mucrosquamatus.

A novel myotoxin, designated TMPB, was purified from the venom of Trimeresurus mucrosquamatus by Sephadex G-100 superfine gel chromatography and fast protein liquid chromatography (FPLC). The N-terminal sequence of 24 amino acid residues was determined by protein sequencer. The sequence similarities between TMPB and other two phospholipase A(2) (PLA2s) previously purified from the same venom were 41.7% and 54.2%, respectively, but TMPB showed no detectable PLA(2) hydrolytic activity. Its molecular weight was estimated to be 16 000 by reducing SDS-PAGE and isoelectric point was determined to be 9.2 by isoelectric focusing electrophoresis. TMPB exhibited strong myotoxicity and platelet aggregation inhibiting activity, and the two activities could all be inhibited by heparin.

A novel platelet glycoprotein Ib-binding protein with human platelet aggregation-inhibiting activity from Trimeresurus jerdonii venom.

Platelet glycoprotein Ib (GPIb) is a primary adhesion receptor and involved in platelet-related disorders. However, it is difficult to study GPIb-specific platelet stimulation using physiological ligands in vivo. GPIb-binding snake C-type lectins (snaclecs) are useful tools for exploring GPIb in vitro because they act on platelets differently. In the present study, a novel GPIb-binding snaclec, named jerdonibitin, was purified, molecular cloned and characterized from Trimeresurus jerdonii venom. On SDS-polyacrylamide gel electrophoresis, it showed a single band with an apparent molecular weight of 25 kDa under non-reducing conditions and two distinct bands with apparent molecular weights of 15 kDa (α-subunit) and 13 kDa (ß-subunit) under reducing conditions. The cDNA sequences of each subunit of jerdonibitin were identified and both deduced amino acid sequences were confirmed by N-terminal protein sequencing and trypsin-digested peptide mass fingerprinting of MALDI-TOF. Sequence alignment showed that jerdonibitin is a snaclec and has sequence similarity with TSV-GPIb-BP (a GPIb-inhibitory snaclec). Jerdonibitin dose-dependently inhibited platelet aggregation induced by ristocetin or low-dose thrombin, but not by high-dose thrombin. The GPIbα was detected by affinity chromatography on jerdonibitin. In vivo, jerdonibitin also dose-dependently induced thrombocytopenia of mice and platelet counts remained at very low level after 18 h intravenous injection. In summary, a novel GPIb-inhibitory snaclec was molecular cloned and characterized, which might provide insights into investigation of how GPIb-inhibitory snaclecs work and development of new antiplatelet agents.