Description of two new myxosporean species parasitic in freshwater fishes from the Yangtze River in China

Two new species of myxosporeans (Myxosporea: Myxidiidae), Myxidium tuanfengensis sp. n. and Zschokkella saurogobionis sp. n., Parasitic in freshwater fishes collected from the Yangtze River of China are described in this paper. M. tuanfengensis was found in the liver parenchyma and intestine lumen of Leptobotia taeniops Sauvage, 1878, while Z. saurogobionis was found in the gall bladder of Saurogobio dumerili Bleeker, 1871. The diagnostic characters of M. tuanfengensis are: round or elliptical polysporous plasmodia averaging 118 mum in size; spore oval in frontal view with smooth surface and nearly spindle-shape in sutural view with slightly sinuous sutural ridge, averaging 19.5 x 9.75 x 8.9 mum in size; two large spherical polar capsules 6.8 mum in diameter, with polar filament wound in 4 to 5 coils. The diagnostic characters of Z. saurogobionis are: spore elliptical in both frontal and sutural view measuring 18.3 x 9.8 x 10.8 mum in size; fine sutural ridge in S-form, spore shell marked with 10 to 12 distinct lines paralleled with the sutural line; two spherical polar capsules, 6.7 mum in diameter, with polar filament in 5 coils.

A Plant Needs Ants like a Dog Needs Fleas: Myrmelachista schumanni Ants Gall Many Tree Species to Create Housing

Hundreds of tropical plant species house ant colonies in specialized chambers called domatia. When, in 1873, Richard Spruce likened plant-ants to fleas and asserted that domatia are ant-created galls, he incited a debate that lasted almost a century. Alth

紫茎泽兰生态学特征及入侵策略

紫茎泽兰（Eupatorium adenophorum）是臭名昭著的世界恶性杂草之一，目前全世界已有30多个国家和地区遭受到它的入侵危害，因此引起了全社会各方面广泛的关注。我国西南部是紫茎泽兰入侵并造成严重危害的地区之一，本文以四川省攀西地区紫茎泽兰入侵危害严重的生态系统为研究对象，分别对不同生境条件下各年龄紫茎泽兰的生长状况、幼苗生长动态、不同类型群落中紫茎泽兰的种群变化规律以及泽兰实蝇防治紫茎泽兰现状进行研究，分析紫茎泽兰生态学特征及入侵策略，以揭示紫茎泽兰的入侵机制。 　　不同生境条件下相同年龄紫茎泽兰其生长状况有很大的不同：当年生紫茎泽兰幼苗在偏阴和灌丛遮荫环境下生长状况优于偏阳生境下，一年生以上的成熟植株生长情况则相反;紫茎泽兰在其单优群落中的生长状况明显优于灌丛中伴生的紫茎泽兰，说明一定程度的遮荫、植被覆盖及竞争对紫茎泽兰生长有一定的抑制作用。不同种类的灌木对紫茎泽兰生长的影响亦有所不同，其中，马桑（Coriaria sinica）等冠幅较大、性喜阴湿的落叶类灌木对紫茎泽兰幼苗萌发、种群更新有庇护和促进作用，而其他类冠幅小、常绿或落叶、且生于干旱生境下的灌木，则不利于紫茎泽兰幼苗萌发及种群更新，有些甚至会产生化感物种抑制紫茎泽兰的生长。 　　紫茎泽兰种子萌发属投机式萌发，一年内只要有适合的温湿条件都可以萌发。种子萌发的高峰期主要集中在雨季，冬春干旱季节萌发率很低。紫茎泽兰为常绿半灌木，终年可持续生长，生长速率受光照、湿度和温度影响显著。秋季萌发的紫茎泽兰幼苗在越冬及干旱季节中，各项生长指标（包括主茎长度、总叶面积、基径等）增长缓慢，一年之内平均月增长量由高到低的顺序分别为：偏阳生境＞全荫湿润生境＞灌丛遮荫生境，生长旺期为雨季约6 ~10月份;秋季萌发越年生实生苗生长节律与当年生实生苗相似，但生长周期不同于雨季萌发苗，需经过两个冬季才能开花结实完成其生活史;紫茎泽兰生活史循环过程，通过有性生殖与无性生殖相互补的繁殖策略进行种群的更新与扩散，进而达到入侵的目的。 　　泽兰实蝇（Procecidochares utilis）作为天敌控制紫茎泽兰已经在国内外得到广泛的应用，但关于它对紫茎泽兰控制的有效性和防治现状的研究尚不深入。本文通过对攀西地区紫茎泽兰入侵危害严重的路域生态系统中泽兰实蝇寄生状况的抽样调查，初步研究了泽兰实蝇对紫茎泽兰生长，特别是生殖能力的影响。研究结果表明：1）植株寄生率与枝条寄生率有显著差异（p﹤0.05），分别为71.67% 和17.30%，前者显著高于后者;样方调查结果显示，成熟群落中枝条寄生率为17.48枝•m-2;1虫瘿•枝条-1的枝条占所有寄生枝条的92.30%;2）湿润生境下紫茎泽兰的枝条寄生率为20.27%，显著高于干旱生境下的枝条寄生率（9.33%）（p﹤0.05）;3）不同年龄植株枝条寄生率有差异，0 ~1年生植株枝条寄生率分别为36.36%和21.56%，显著高于2 ~4年生的植株枝条寄生率，后者分别为13.50%，8.82%及12.16%（p﹤0.05）;4）在目前的寄生强度下，泽兰实蝇对紫茎泽兰枝条的直径、花枝量、头状花序数及结实量均无显著影响（p﹥0.05）。因此可以推断，目前单一的引进泽兰实蝇进行天敌控制不能达到预期的防治目标，天敌的引入也应慎重考虑。 　　紫茎泽兰能够利用与当地大多数植物种类生长节律的时间差异，通过首先占领时间生态位而达到占据空间生态位，最终导致严重的入侵危害。在不同类型的群落中，紫茎泽兰种群利用不同的适应策略进行入侵。自然和人工播种样地中，紫茎泽兰种群与群落状况的变化规律均呈相反趋势。对于一个成熟的紫茎泽兰种群，一旦其定居后即能很好的利用时间和空间生态位的空缺的来促进其优势地位的增强和巩固，从而逐渐增加其入侵程度，造成越来越大的灾害;而对于一个郁蔽度较好且较完整的群落，紫茎泽兰通过幼苗进行扩张以达到入侵的途径通常比较困难，只有在发生人为活动干扰时，才有可能通过投机式繁殖方式进入群落内部定居，继而通过克隆生殖的方式进行入侵。

大蹼铃蟾抗菌肽22 对膀胱癌细胞株HLA-ABC以及DR表达影响的对照实验研究

　目的　探讨大蹼铃蟾抗菌肽22 (Maximin22) 对膀胱癌 细胞株HLA2DR 及HLA2ABC 表达的影响, 并与TNF2α、 IFN2α进行比较。方法　采用肿瘤细胞培养方法,流式细胞 仪检测各实验样品对膀胱癌细胞株T24 、BIU287 、SCaBER 的HLA2DR 及HLA2ABC 表达的影响。结果　Maximin22 对 不同的膀胱癌细胞株在小剂量下即有抑制作用,并呈剂量相 关性,各实验样品未见对各膀胱癌细胞株的HLA2DR 表达 有影响,Maximin22 、TNF2α对HLA2ABC 的表达均无影响; IFN2α则对HLA2ABC 的表达有上调作用。结论　Maximin2 2 、TNF2α抗癌机制与提高肿瘤细胞HLA2DR、ABC 的表达无 关, IFN2α可通过提高肿瘤细胞HLA2ABC 的表达提高T 细 胞对膀胱肿瘤的识别杀伤能力。

大蹼铃蟾抗菌肽- 2 与IFN2α22b 和TNF2α对膀胱癌细胞株抑制活性的实验研究

目的:比较大蹼铃蟾抗菌肽- 2 (Maximin 2) 与肿瘤坏死因子2α(TNF2α) 、干扰素2α22b ( IFN2α22b) 对不同膀胱癌细胞株的抑制杀伤作用。方法:采用细胞培养及MTT 比色法,检测Maximin 2 、TNF2α及 IFN2α22b 对3 个不同膀胱癌细胞株的抑制作用及作用特点,计算量效回归曲线及50 %抑制率。结果: Maximin 2 对不同的膀胱癌细胞株在100μgPmL 左右(48 h) 即达到50 %抑制率浓度( IC50) ,并呈剂量相 关性,与TNF2α、IFN2α22b 抑制作用的表现形式不同。Maximin 2 抑制率最高表现在第48 h ,以后逐渐减 弱, TNF2α、IFN2α22b 则在前24 h 作用较弱,以后逐渐增强。结论:Maximin 2 对不同的膀胱癌细胞株均 有较强的抑制作用,同TNF2α、IFN2α22b 比较其作用机制有所不同,Maximin 2 对膀胱癌细胞株的杀伤作 用可能主要是通过对肿瘤细胞的直接抑制,并且相对容易失活。

Interference Competition and High Temperatures Reduce the Virulence of Fig Wasps and Stabilize a Fig-Wasp Mutualism

Fig trees are pollinated by fig wasps, which also oviposit in female flowers. The wasp larvae gall and eat developing seeds. Although fig trees benefit from allowing wasps to oviposit, because the wasp offspring disperse pollen, figs must prevent wasps fr

Taxonomic review of the genus Sinocrossocheilus Wu (Teleostei : Cyprinidae), with a description of four new species

All Sinocrossocheilus species, except S. microstomatus, are reviewed. Four new species, S. labiata, S. papillolabra, S. nigrovittata, and S. longibulla, are described. The genus Sinocrossocheilus differs from other genera of Cyprinidae by the last simple dorsal fin ray being unserrated and unossified, the last unbranched anal fin ray being unserrated and unossified, the 5-branched anal fin rays, the mouth gap being inferior, the rostral cap covering the lower jaw and connecting directly with the lower lip, a row of fleshy lobes on the lower jaw, and a cloudy black spot above the pectoral fin. Sinocrossocheilus labiata is small and has 22 predorsal scales; S. longibulla has a very large air bladder; S. papillolabra possesses a well-developed ventral fin and a wide band covered by fleshy papillae on the lower lip; and S. nigrovittata possesses black longitudinal stripes along the lateral line. Crossocheilus bamaensis and Crossocheilus liuchengensis are transferred to the genus Sinocrossocheilus. Sinocrossocheilus species are endemic to the central and eastern Yunnan-Guizhou Plateau of China, where river systems are anfractuous, including seasonal rivers, cave rivers, underground rivers, and streamlets between mountains. These separated rivers probably provide conditions for the allopatric speciation of the Sinocrossocheilus.

Schistura cryptofasciata, a new loach (Cypriniformes : Balitoridae) from Salween drainage in Yunnan, Southwestern China

Schistura cryptofasciata is distinguished from its congeners by following combination characters: lateral line complete; 8(1)/(2) branched dorsal-fin rays; 9+8 branched caudal-fin rays; no sexual dimorphism; 8-11 indistinct bars, wider than interspaces; caudal-peduncle length 44.1-16.5% standard length, 68.1-90.4% dorsal head length; anterior portion of body scaleless; air bladder entirely embedded in bony capsule; lateral head length 104-122% dorsal head length; lower jaw with a notch at symphysis; lower lip completely interrupted; interorbital width 1.9-2.2 times eye diameter; pelvic-fin origin ventral to dorsal-fin origin; anus 1.0-1.5 eye diameters in front of anal-fin origin; the widest part of black basal caudal bar is the midlateral, and then the upper and lower ends.

Pseudobagrus fui Miao, a valid bagrid species from the Yangtze River drainage, South China (Teleostei: Bagridae)

Pseudobagrus fui Miao is a valid bagrid species that can be separated from all its congeners in having 27-33 anal-fin rays. Among the species of Pseudobagrus, it forms part of a group of approximately 20 species putatively characterized by having a smooth anterior margin of the pectoral-fin spine and short maxillary barbels not extending to the base of the pectoral-fin spine. Pseudobagrus fui, together with P. nitidus and P. vachelli, can be differentiated from all other fork-tailed species of this group by having no fewer than 20 branched anal-fin rays, the posterior end of the anal-fin base posterior to the vertical through the posterior end of the adipose-fin base, and anal-fin base longer than the adipose-fin base. It further differs from P. nitidus in having a gas bladder without beaded lateral and posterior margins, and from P. vachelli in having short maxillary barbels not extending to the base of the pectoral-fin spine. Pseudobagrus fui is currently known from the main stream of the upper Yangtze River and its tributaries, the Min River, Jialing River, Tuo River, Wu River and Chishui River in Sichuan Province, Guizhou Province, and the Chongqing City. The identity and nomenclature of Pseudobagrus nitidus is also discussed.

Predominant expression and cellular distribution of fish Agr2 in renal collecting system

Anterior gradient 2 (Agr2) genes encode secretory proteins, and play significant roles in anterior-posterior patterning and tumor metastasis. Agr2 transcripts were shown to display quite diverse tissue distribution in different species, and little was known about the cellular localization of Agr2 proteins. In this study, we identified an Agr2 homologue from gibe[ carp (Carassius auratus gibelio), and revealed the expression patterns and cellular localization during embryogenesis and in adult tissues. The full-length cDNA of CagAgr2 is 803 nucleotides (nt) with an open reading frame of 510 nt encoding 169 amino acids. The Agr2 C-terminus matches to the class I PDZ-interacting motif, suggesting that it might be a PDZ-binding protein. During embryogenesis, CagAgr2 was found to be transcribed in the mucus-secreting hatching gland from tailbud stage and later in the pharynx region, swim bladder and pronephric duct as revealed by RT-PCR and whole mount in situ hybridization. In the adult fish, its transcription was predominantly confined to the kidney, and lower transcription levels were also found in the intestine, ovary and gills. To further localize the Agr2 protein, the anti-CagAgr2 polyclonal antibody was produced and used for immunofluorescence observation. In agreement with mRNA expression data, the Agr2 protein was localized in the pronephric duct of 3dph larvae. In adult fish, Agr2 protein expression is confined to the renal collecting system with asymmetric distribution along the apical-basolateral axis. The data provided suggestive evidence that fish Agr2 might be involved in differentiation and secretory functions of kidney epithelium. (C) 2009 Elsevier Inc. All rights reserved.

Apo-14 is required for digestive system organogenesis during fish embryogenesis and larval development

Apo-14 is a fish-specific apolipoprotein and its biological function remains unknown. In this study, CagApo-14 was cloned from gibel carp (Carassius auratus gibelio) and its expression pattern was investigated during embryogenesis and early larval development. The CagApo-14 transcript and its protein product were firstly localized in the yolk syncytial layer at a high level during embryogenesis, and then found to be restricted to the digestive system including liver and intestine in later embryos and early larvae. Immunofluorescence staining in larvae and adults indicated that CagApo-14 protein was predominantly synthesized in and excreted from sinusoidal endothelial cells of liver tissue. Morpholino knockdown of CagApo-14 resulted in severe disruption of digestive organs including liver, intestine, pancreas and swim bladder. Moreover, yolk lipid transportation and utilization were severely affected in the CagApo-14 morphants. Overall, this data indicates that CagApo-14 is required for digestive system organogenesis during fish embryogenesis and larval development.

Triplophysa waisihani, a new species of nemacheiline loach from Northwest China (Pisces: Balitoridae)

Triplophysa waisihani, a new species of nemacheiline loach, is described from the Kax River, a tributary of the Ili River drainage in Xinjiang-Uighur Autonomous Region of Northwest China. It can be assigned to the T. labiata species group characterized by having widely separated anterior and posterior nostrils and no breeding tubercles on the sides of the head. Triplophysa waisihani resembles T. labiata and T. herzensteini, but differs from both in cephalic sensory-canal pattern and the structure of the gas bladder; from T. labiata in the structure of the pelvic girdle and absence or presence of the fourth basibranchial; and from T. herzensteini in the shape of the anal fin.

Triplophysa lixianensis, a new nemacheiline loach species (Pisces : Balitoridae) from the upper Yangtze River drainage in Sichuan Province, South China

Triplophysa lixianensis, a new nemacheiline loach species, is described from the Min Jiang of the upper Yangtze River drainage in Sichuan Province, South China. It can be separated from all other species of Triplophysa by having a unique combination of the following characters: posterior chamber of gas bladder greatly reduced or absent; caudal peduncle columnar with a roughly round cross- section at its beginning; anterior edge of lower jaw completely exposed or uncovered by lower lip; intestine short, forming a zigzag loop below stomach; dorsal- fin origin closer to caudal- fin base than to snout tip; pelvic fin inserted anterior to dorsal- fin origin; snout length 50.6 - 57.5 % of head length; eye diameter 12.3 15.4 % of head length; caudal peduncle length 25.1 - 27.1 % of standard length; anal fin with five branched rays; lower lip greatly furrowed with two thick lateral lobes; and body smooth or scaleless.

Early ontogeny of Ancherythroculter nigrocauda and effects of delayed first feeding on larvae

Development of embryos and larvae in Ancherythroculter nigrocauda Yih et Woo (1964) and effects of delayed first feeding on larvae were observed after artificial fertilization. The fertilized eggs were incubated at an average temperature of 26.5 degrees C (range: 25.7-27) and the larvae reared at temperatures ranging from 21.8 to 28 degrees C. First cleavage was at 50 min, epiboly began at 7 h 5 min, heartbeat reached 72 per min at 24 h 40 min and hatching occurred at 43 h 15 min after insemination. Mean total length of newly hatched larvae was 4.04 +/- 0.03 mm (n = 15). A one-chambered gas bladder was observed at 70 h 50 min, two chambers occurred at 15 days, and scales appeared approximately 30 days after hatching. Larvae began to feed exogenously at day 4 post-hatch at an average temperature of 24 degrees C. Food deprivation resulted in a progressive atrophy of skeletal muscle fibres, deterioration of the larval digestive system and cessation of organ differentiation. Larval growth under food deprivation was significantly affected by the time of first exogenous feeding. Starved larvae began to shrink, with negative growth from day 6 post-hatch. The point of no return (PNR) was reached at day 11 after hatching. Mortality of starved larvae increased sharply from day 12 after hatching.

Population genetic structure of an endemic cyprinid fish, Ancherythroculter nigrocauda, in the upper reaches of the Yangtze River and its implication for conservation

Ancherythroculter nigrocauda is a cyprinid fish endemic to the upper reaches of the Yangtze River, which has been reported to have 2 or 3 chambers to its air bladder. Morphological studies showed no differences between individuals with different types of air bladder, but did demonstrate geographical differences from different sources. After the completion of the Three Gorges Dam, it was expected that the population of this species would decrease, but artificial breeding and stocking is under consideration to protect this species from extinction. In the present study, mtDNA cytochrome b gene sequences were determined and analyzed for A. nigrocauda samples of different morphotypes and sources to identify their genetic differentiations, and thereby guide plans for the artificial propagation and conservation of this species. Haplotype diversity index values (h) and nucleotide diversity values (pi) for all the populations were found to be high indicating their high level genetic diversity. An analysis of molecular variance identified no differentiation among the studied populations. Therefore, we suggested that the individuals of different morphological types and geographical sources belong to the same species. To maintain its high level genetic diversity, it mill he necessary to use large and diverse sources of parental fish for artificial reproduction.