High Endemicity with Clonorchis sinensis Metacercariae in Fish from Yongjeon-cheon (Stream) in Cheongsong-gun,Gyeongsangbuk-do,Korea

The infection status with Clonorchis sinensis metacercariae (CsMc) was examined in freshwater fishes from Yongjeon-cheon (a branch of Nakdong-gang) located in Cheongsong-gun, Gyeongsangbuk-do, the Republic of Korea (Korea). A total of 750 fishes in 19 species were examined by the artificial digestion method for 2 years (2019 and 2020). CsMc were detected in 378 (51.4%) out of 735 fishes in 14 species (73.7%), and the infection intensity was 666 per fish infected. In 2019, CsMc were found in 172 (68.0%) out of 253 fishes in 10 species, and the infection intensity was 565 per fish infected. In 2020, CsMc were detected in 206 (62.2%) out of 331 fishes in 10 species, and the infection intensity was 751 per fish infected. The other zoonotic trematode, ie. Metagonimus spp., Centrocestus armatus, Echinostoma spp. and Clinostomum complanatum, metacercariae were also detected in fishes from the survey streams, but their endemicities were relatively low. Conclusively, it was first confirmed that CsMc are highly endemic in fishes from Yongjeon-cheon in Cheongsong-gun, Gyeongsangbuk-do, Korea.     

Role of capsaicin sensory nerves and EGF in the healing of gastric ulcer in rats

Accumulating evidence indicates that capsaicin sensitive afferent fibers play a pivotal role not only in gastroprotection but also in ulcer healing. Denervation of capsaicin sensitive afferent fibers exerts an adverse action on these effects. However, whether such an action is mediated through a depression on epidermal growth factor (EGF) is undefined. In this study, the effects of denervation of sensory neurons with capsaicin (100 mg/kg, s.c.) on acetic acid-induced chronic gastric ulcers and their relationship with the EGF expression in salivary glands, serum and gastric mucosa were investigated. Capsaicin significantly increased ulcer size, decreased gastric mucosal cell proliferation at the ulcer margin, angiogenesis in the granulation tissue and also gastric mucus content. Ulcer induction by itself dramatically elevated EGF levels in salivary glands and serum on day 1 and 4, and also in the gastric mucosa on day 4. However, capsaicin completely abolished these effects. It is concluded that stimulation of EGF expression in salivary glands and serum may be one of the mechanisms by which capsaicin sensitive nerves contribute to the gastroprotective and ulcer healing actions in the stomach.     

House dust mite extract activates apical Cl− channels through protease‐activated receptor 2 in human airway epithelia

Adequate fluid secretion from airway mucosa is essential for maintaining mucociliary clearance, and fluid hypersecretion is a prominent feature of inflammatory airway diseases such as allergic rhinitis. House dust mite extract (HDM) has been reported to activate protease‐activated receptors (PARs), which play various roles in airway epithelia. However, the role of HDM in regulating ion transporters and fluid secretion has not been investigated. We examined the effect of HDM on ion transport in human primary nasal epithelial cells. The Ca²⁺‐sensitive dye Fura2‐AM was used to determine intracellular Ca²⁺ concentration ([Ca²⁺]_i) by means of spectrofluorometry in human normal nasal epithelial cells (NHNE). Short‐circuit current (Isc) was measured using Ussing chambers. Fluid secretion from porcine airway mucosa was observed by optical measurement. HDM extract (10 µg/Ml) effectively cleaved the PAR‐2 peptide and induced an increase of [Ca²⁺]_i that was abolished by desensitization with trypsin, but not with thrombin. Apical application of HDM‐induced Isc sensitive to both a cystic fibrosis transmembrane conductance regulator (CFTR) inhibitor and a Ca²⁺‐activated Cl^? channel (CaCC) inhibitor. HDM extract also stimulated fluid secretion from porcine airway mucosa. HDM extract activated PAR‐2 and apical Cl^? secretion via CaCC and CFTR, and HDM‐induced fluid secretion in porcine airway mucosa. Our results suggest a role for PAR‐2 in mucociliary clearance and fluid hypersecretion of airway mucosa in response to air‐borne allergens such as HDM. J. Cell. Biochem. 109: 1254–1263, 2010. © 2010 Wiley‐Liss, Inc.     

Senescent phenotype can be reversed by reduction of caveolin status

Hyporesponsiveness to growth factors is one of the fundamental characteristics of senescent cells. We previously reported that the up-regulation of caveolin attenuates the growth factor response and the subsequent downstream signal cascades in senescent human diploid fibroblasts. Therefore, in the present experiment, we investigated the modulation of caveolin status in senescent cells to determine the effect of caveolin on mitogenic signaling efficiency and cell cycling. We reduced the level of caveolin-1 in senescent human diploid fibroblasts using its antisense oligonucleotides and small interfering RNA, and this resulted in the restoration of normal growth factor responses such as the increased phosphorylation of Erk, the nuclear translocation of p-Erk, and the subsequent activation of p-Elk upon epidermal growth factor stimulation. Moreover, DNA synthesis and the re-entry of senescent cells into cell cycle were resumed upon epidermal growth factor stimulation concomitantly with decreases in p53 and p21. Taken together, we conclude that the loss of mitogenic signaling in senescent cells is strongly related to their elevated levels of caveolin-1 and that the functional recovery of senescent cells at least in the terms of growth factor responsiveness and cell cycle entry might be achieved simply by lowering the caveolin level.     

ABA对叶子花正常叶和变态叶部分生理生化指标的影响(研究简报)

为探索ABA对叶子花正常叶和变态叶部分生理生化指标的影响,利用不同浓度ABA溶液处理叶子花正常叶和变态叶,6h后,测定其叶绿素、可溶性糖、可溶性蛋白、游离脯氨酸含量和SOD酶活性.结果表明:处理后,变态叶和正常叶的叶绿素含量,SOD酶活性,游离脯氨酸含量和变态叶可溶性糖含量均先增加后降低,在ABA浓度为100 μmol/L时最大.正常叶的可溶性糖含量、正常叶和变态叶的可溶性蛋白含量在ABA浓度为50 μmol/L时最大.这表明50～100 μmol/L浓度的ABA能提高叶子花的抗逆性.     

Simultaneous nitrification and denitrification in a mixed methanotrophic culture

Simultaneous nitrification and denitrification using a mixed methanotrophic culture was investigated. When both NO₃ ^–-N (108 mg l^–1) and NH₃-N (59 mg l^–1) were added into batch reactors, nitrate removal was complete within 10 h at the rate of 47 mg NO₃ ^–-N g VSS^–1 day^–1 when dissolved oxygen (DO) concentration was maintained at 2 mg DO l^–1. Ammonia removal started simultaneously with nitrate removal at a slower rate of 14 NH₃-N g VSS^–1 day^–1. No significant accumulation of nitrite or nitrate during ammonia utilization suggested the occurrence of simultaneous nitrification and denitrification.     

灌浆期高温对冬小麦籽粒氨基酸含量和组成的影响

以强筋小麦品种郑麦366和中筋小麦品种洛旱2号为材料,采用盆栽和人工气候室模拟的方法,研究了花后不同时段(灌浆前期即花后5 d,灌浆中期即花后15 d)和持续时间(处理2 d和4 d)的高温胁迫对籽粒氨基酸含量和积累量(以单粒中氨基酸含量表示)的影响。结果显示:(1)高温胁迫显著增加了小麦籽粒中必需氨基酸(EAA)、非必需氨基酸(NAA)和总氨基酸(TAA)含量,但降低了其积累量和EAA/TAA,2品种表现一致;(2)灌浆前期高温胁迫对2品种籽粒氨基酸含量的影响大于灌浆中期,而对氨基酸积累量的影响则相反;(3)高温持续时间对籽粒氨基酸含量的影响在2品种间存在差异,洛旱2号籽粒赖氨酸、EAA、NAA和TAA含量均随高温持续时间的延长显著增加,而郑麦366籽粒中上述指标仅在高温胁迫4 d下较对照增加显著;(4)从受高温胁迫的影响看,籽粒EAA/TAA对高温时段更敏感,而氨基酸含量表现为更易受高温持续时间的影响;(5)高温时段与持续时间的互作效应体现在:灌浆前期籽粒氨基酸积累量2品种均以高温胁迫4 d的影响最大,而灌浆中期则均以高温2 d的降幅最大。上述结果表明,小麦籽粒氨基酸及其组分对高温胁迫的响应不仅在品种间存在差异,且受高温时段和持续时间的影响。     

ATP‐dependent DNA binding,unwinding, and resection by the Mre11/Rad50 complex

ATP‐dependent DNA end recognition and nucleolytic processing are central functions of the Mre11/Rad50 (MR) complex in DNA double‐strand break repair. However, it is still unclear how ATP binding and hydrolysis primes the MR function and regulates repair pathway choice in cells. Here, Methanococcus jannaschii MR‐ATPγS‐DNA structure reveals that the partly deformed DNA runs symmetrically across central groove between two ATPγS‐bound Rad50 nucleotide‐binding domains. Duplex DNA cannot access the Mre11 active site in the ATP‐free full‐length MR complex. ATP hydrolysis drives rotation of the nucleotide‐binding domain and induces the DNA melting so that the substrate DNA can access Mre11. Our findings suggest that the ATP hydrolysis‐driven conformational changes in both DNA and the MR complex coordinate the melting and endonuclease activity.     

Comprehensive Annotation of Physcomitrella patens Small RNA Loci Reveals That the Heterochromatic Short Interfering RNA Pathway Is Largely Conserved in Land Plants

Many plant small RNAs are sequence-specific negative regulators of target mRNAs and/or chromatin. In angiosperms, the two most abundant endogenous small RNA populations are usually 21-nucleotide microRNAs (miRNAs) and 24-nucleotide heterochromatic short interfering RNAs (siRNAs). Heterochromatic siRNAs are derived from repetitive regions and reinforce DNA methylation at targeted loci. The existence and extent of heterochromatic siRNAs in other land plant lineages has been unclear. Using small RNA-sequencing (RNA-seq) of the moss Physcomitrella patens, we identified 1090 loci that produce mostly 23- to 24-nucleotide siRNAs. These loci are mostly in intergenic regions with dense DNA methylation. Accumulation of siRNAs from these loci depends upon P. patens homologs of DICER-LIKE3 (DCL3), RNA-DEPENDENT RNA POLYMERASE2, and the largest subunit of DNA-DEPENDENT RNA POLYMERASE IV, with the largest subunit of a Pol V homolog contributing to expression at a smaller subset of the loci. A MINIMAL DICER-LIKE (mDCL) gene, which lacks the N-terminal helicase domain typical of DCL proteins, is specifically required for 23-nucleotide siRNA accumulation. We conclude that heterochromatic siRNAs, and their biogenesis pathways, are largely identical between angiosperms and P. patens, with the notable exception of the P. patens-specific use of mDCL to produce 23-nucleotide siRNAs.