Tadpoles of three common anuran species from Thailand do not prey on mosquito larvae

Tadpoles are often considered to be predators of mosquito larvae and are therefore beneficial for the control of certain disease vectors. Nevertheless, only a few species have actually been recorded to prey on mosquito larvae. The mosquito larvae predation rates of tadpoles of three common Thai anuran species (Bufo melanostictus, Kaloula pulchra and Hylarana raniceps) were experimentally tested. Tadpoles in varying developmental stages were used to assess a size/age effect on the predation rate. In addition, different instars of Culex quinquefasciatus were used in order to assess a prey size effect on the predation rates. All three species failed to show any evidence of mosquito larvae predation. Neither small nor large tadpoles fed on mosquito larvae. Prey size also did not affect predation. Although tadpoles do not feed on mosquito larvae, there may be other direct or indirect inter‐specific interactions that adversely impact the development of larvae in shared habitats with tadpoles.     

沼水蛙繁殖习性与食性的初步研究

报道了广东省韶关地区沼水蛙(Hylarana)的生态习性,该蛙在韶关地区的繁殖期为3—5月,繁殖期雌雄性比为1：2．02;雄蛙个体一般小于雌蛙个体,具备繁殖能力的雄蛙最小体长为61．18mm,平均体长为71．73mm,雌性最小体长为63．57mm,平均体长为73．38mm;雌蛙卵巢内有两种不同大小的卵球。沼水蛙的主要食物为鞘翅目、直翅目、鳞翅目的昆虫。     

沼水蛙繁殖期鸣声特征及鸣叫节律

鸣叫对无尾两栖类动物的生存与繁殖起重要作用。蛙类的鸣叫行为受到环境因素影响表现出一定的节律性。2016年8和9月,采用录音机和指向性话筒,在野外录制了57只沼水蛙（Hylarana guentheri）的鸣声并对其鸣声特征进行分析;通过悬挂录音笔和自动温湿度记录仪研究了沼水蛙鸣叫节律（17 d）及其与环境温度、相对湿度的关系。结果显示,沼水蛙的鸣声由1 ~ 4个音节组成,不同类型鸣声间的音节主频、音节时长存在显著差异（P < 0.05）。该物种全天具有鸣叫行为,13:00 ~ 14:00时为鸣叫高峰期。白天单音节鸣声、双音节鸣声、三音节鸣声、总鸣声和总音节的数量较夜晚显著增加（P < 0.01）。鸣声数量和音节数量均与环境温度呈正相关（P < 0.01）。结果表明,沼水蛙通过改变音节数量、音节主频和音节时长改变鸣叫策略。沼水蛙的鸣叫行为具有昼夜节律性且受环境温度的影响。     

三种不同科属蛙类外周血细胞的比较

采用快速瑞氏-姬姆萨(Wright’s-Giemsa’s)染色法对斑腿泛树蛙(Polypedates megacephalus)和沼水蛙(Hylarana guentheri)的外周血细胞进行观察,并与北部湾棱皮树蛙(Theloderma corticale)已有的数据进行了比较。结果显示,三种蛙的血细胞均由红细胞、白细胞和血栓细胞组成,三种蛙的血细胞在形态结构上具有一定的共性,但在形态大小、数量上差异显著。沼水蛙的红细胞长径和短径均显著大于其余两种,分别为(23.56±2.78)μm和(14.25±1.62)μm;3种蛙的嗜中性粒细胞和小淋巴细胞在大小上没有明显差别,但北部湾棱皮树蛙的嗜酸性粒细胞和嗜碱性粒细胞的长径、短径均显著大于其他两种蛙。北部湾棱皮树蛙的红细胞数量显著少于其余两者,为(24.33±9.46)×10⁴/mm³;斑腿泛树蛙白细胞数量显著少于其余两种蛙,为(1.40±0.40)×10⁴/mm³。这些差异的产生可能与其生活环境以及生活习性有关。     

Molecular cloning and characterization of antimicrobial peptides from skin of the broad-folded frog, Hylarana latouchii

Seven cDNA sequences encoding antimicrobial peptide (AMP) precursors were cloned by screening the skin-derived cDNA library of the broad-folded frog, Hylarana latouchii. Seven of the deduced peptides are highly similar to AMPs in five families of brevinin-2 (brevinin-2LTa, brevinin-2LTb, and brevinin-2LTc), esculentin-1 (esculentin-1LTa), esculentin-2 (esculentin-2LTa), palustrin-2 (palustrin-2LTa), and temporin (temporin-LTe). The actual sequences and characteristics of mature AMPs were analyzed by RP-HPLC and LC–MS/MS-based proteomics approaches in combination of four different protein digestion processes and by LTQ XL in combination of gas-phase fractionation (GPF) analysis. Moreover, most of the peptides found in this study hardly display hemolytic activity in vitro, suggesting they are promising antimicrobial drug candidates.     

沼水蛙早期胚胎发育的初步研究

报道了沼水蛙的早期胚胎发育过程。根据胚胎发育过程中的形态变化规律将胚胎发育过程分为2 5个时期 ,在室温 (2 4± 1 )℃的条件下 ,胚胎发育历时 1 87h 5 4min ;在室外不控制温度 ,气温为 1 8～ 2 5℃的条件下 ,历时 2 1 5h 3 0min。本文还描述了各时期的形态特征 ,并讨论了发育中的一些现象。     

澳门发现台北纤蛙

2014年6月,在澳门进行两栖爬行动物调查期间,在九澳湿地采集到2只台北纤蛙(Hylarana taipehensis),为澳门首次发现此物种。近年来调查表明,澳门台北纤蛙的种群数量十分稀少,需要加强种群动态监测和保护工作。     

Advertisement calls of Guenther’s frog Hylarana guentheri (Anura: Ranidae) during the breeding season

Acoustic signalling is the most important form of communication in anuran amphibians. Here we recorded and analysed the calls of 18 male Guenther’s frogs (Hylarana guentheri) from the wild during the breeding season. The advertisement calls of H. guentheri were composed of from a single note to five notes, with three-note calls the most recorded. All individuals produced calls around 600 Hz but calls ranged from 470 to 2600 Hz. Comparing the differences between individuals calls, we found within-male coefficients of variation (CV_w) of call intensity, the fundamental frequency, the first formant, the second formant, the third formant and the fourth formant were static (less than 5% variation), whereas those of note duration, call duration, call interval, numbers of pulses and dominant frequency were dynamic (larger than 15% variation). Comparisons of the call characteristics of H. guentheri in this study with other studies from China, Singapore and Vietnam found call characteristics varied greatly between the five different locations.     

沼水蛙抗菌肽brevinin-2GHa1分离纯化及结构分析

目前,已自青蛙皮肤分泌物中分离获得多种具有较强抗菌活性的多肽．本文利用电刺激法自沼水蛙背腺和耳后腺获得其皮肤分泌物,利用凝胶过滤色谱(Sephadex G-50)和反相高效液相色谱 (reverse-phase high performance liquid chromatography, RP-HPLC)分离纯化,获得一种新型抗菌肽,命名为brevinin- 2GHa1. 抑菌实验显示,该抗菌肽对革兰氏阳性菌和革兰氏阴性菌均有抑制作用,对大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌和沙门氏菌的最小抑制浓度分别为： 7.8、3.9、2.0 μg/mL和250.0 μg/mL. 该抗菌肽在水中为无规卷曲结构,在浓度为10 mmol/L SDS水溶液和不同浓度三氟乙醇水溶液中则呈α-螺旋结构,该抗菌肽结构的研究对阐明其抑菌机制具有重要作用.     

Esc‐1GN shows therapeutic potentials for acne vulgaris and inflammatory pain

The inflammatory response plays important roles in acne vulgaris and pain pathogenesis. In previous study, Esc‐1GN with anti‐inflammatory, antimicrobial, and lipopolysacchride (LPS) binding activity was identified from the skin of the frog Hylarana guentheri. Here, we report its therapeutic potentials for acne vulgaris and inflammatory pain. Esc‐1GN destroyed the cell membrane of Propionibacteria acnes in the membrane permeability assays. In addition, bacterial agglutination test suggested that Esc‐1GN triggered the agglutination of P. acnes, which was affected by LPS and Ca²⁺. Meanwhile, in vivo anti‐P. acnes and anti‐inflammatory effects of Esc‐1GN were confirmed by reducing the counts of P. acnes in mice ear, relieving P. acnes‐induced mice ear swelling, decreasing mRNA expression and the production of pro‐inflammatory cytokines, and attenuating the infiltration of inflammatory cells. Moreover, Esc‐1GN also displayed antinociceptive effect in mice induced by acetic acid and formalin. Therefore, Esc‐1GN is a promising candidate drug for treatment of acne vulgaris and inflammatory pain.