Theileria gilberti n. sp. (Apicomplexa: Theileriidae) in the Gilbert's Potoroo (Potorous gilbertii)

ABSTRACT. The morphology and genetic characterisation of a new species of piroplasm identified in the blood of the Gilbert's potoroo ( Potorous gilbertii ) from the Two Peoples Bay Nature Reserve near Albany, Western Australia, is described from blood and tissue samples from 16 Gilbert's potoroos. Microscopy of blood showed these parasites are highly pleomorphic with a mean length of 1.8 μm and mean width of 0.85 μm. Phylogenetic analysis of 18S rRNA sequence data identified the piroplasm as a new species of Theileria that is closely related to other Australian marsupial piroplasm species. Based on biological and molecular data, it is proposed that the parasite from Gilbert's potoroo be given the name Theileria gilberti n. sp.     

Enhanced litter input rather than changes in litter chemistry drive soil carbon and nitrogen cycles under elevated CO2: a microcosm study

Elevated CO₂ has been shown to stimulate plant productivity and change litter chemistry. These changes in substrate availability may then alter soil microbial processes and possibly lead to feedback effects on N availability. However, the strength of this feedback, and even its direction, remains unknown. Further, uncertainty remains whether sustained increases in net primary productivity will lead to increased long‐term C storage in soil. To examine how changes in litter chemistry and productivity under elevated CO₂ influence microbial activity and soil C formation, we conducted a 230‐day microcosm incubation with five levels of litter addition rate that represented 0, 0.5, 1.0, 1.4 and 1.8 × litterfall rates observed in the field for aspen stand growing under control treatments at the Aspen FACE experiment in Rhinelander, WI, USA. Litter and soil samples were collected from the corresponding field control and elevated CO₂ treatment after trees were exposed to elevated CO₂ (560 ppm) for 7 years. We found that small decreases in litter [N] under elevated CO₂ had minor effects on microbial biomass carbon, microbial biomass nitrogen and dissolved inorganic nitrogen. Increasing litter addition rates resulted in linear increase in total C and new C (C from added litter) that accumulated in whole soil as well as in the high density soil fraction (HDF), despite higher cumulative C loss by respiration. Total N retained in whole soil and in HDF also increased with litter addition rate as did accumulation of new C per unit of accumulated N. Based on our microcosm comparisons and regression models, we expected that enhanced C inputs rather than changes in litter chemistry would be the dominant factor controlling soil C levels and turnover at the current level of litter production rate (230 g C m⁻² yr⁻¹ under ambient CO₂). However, our analysis also suggests that the effects of changes in biochemistry caused by elevated CO₂ could become significant at a higher level of litter production rate, with a trend of decreasing total C in HDF, new C in whole soil, as well as total N in whole soil and HDF.     

Agrobacterium‐produced and exogenous cytokinin‐modulated Agrobacterium‐mediated plant transformation

Agrobacterium tumefaciens is a plant pathogenic bacterium that causes neoplastic growths, called ‘crown gall’, via the transfer and integration of transferred DNA (T‐DNA) from the bacterium into the plant genome. We characterized an acetosyringone (AS)‐induced tumour‐inducing (Ti) plasmid gene, tzs (trans‐zeatin synthesizing), that is responsible for the synthesis of the plant hormone cytokinin in nopaline‐type A. tumefaciens strains. The loss of Tzs protein expression and trans‐zeatin secretions by the tzs frameshift (tzs‐fs) mutant is associated with reduced tumorigenesis efficiency on white radish stems and reduced transformation efficiencies on Arabidopsis roots. Complementation of the tzs‐fs mutant with a wild‐type tzs gene restored wild‐type levels of trans‐zeatin secretions and transformation efficiencies. Exogenous application of cytokinin during infection increased the transient transformation efficiency of Arabidopsis roots infected by strains lacking Tzs, which suggests that the lower transformation efficiency resulted from the lack of Agrobacterium‐produced cytokinin. Interestingly, although the tzs‐fs mutant displayed reduced tumorigenesis efficiency on several tested plants, the loss of Tzs enhanced tumorigenesis efficiencies on green pepper and cowpea. These data strongly suggest that Tzs, by synthesizing trans‐zeatin at early stage(s) of the infection process, modulates plant transformation efficiency by A. tumefaciens.     

Taxonomic notes on the genus Holepyris (Hymenoptera: Bethylidae) from Korea with descriptions of six new species

Six new species of the genus Holepyris (Hymenoptera: Bethylidae: Epyrinae) from Korea are described: H. brevicarinatus sp. nov., H. crinitus sp. nov., H. dimidiatus sp. nov., H. longicephalus sp. nov., H. mucro sp. nov. and H. multo sp. nov. They are described with illustrations of male genitalia and the biometric measurement data. A key to the Korean species of Holepyris based on males is provided.     

Systematics and phylogeography of the Taiwanese endemic minnow Candidia barbatus (Pisces: Cyprinidae) based on DNA sequence,allozymic, and morphological analyses

The phylogeographical patterns of the endemic minnow, Candidia barbatus, were examined using mitochondrial (mt) cytochrome b sequences, allozyme electrophoresis, and morphology. The 23 mtDNA haplotypes recovered were grouped into six lineages (A–F). According to a molecular clock of 1.7% per million years, we estimated that the colonization of C. barbatus to Taiwan took place three million years ago with several subsequent vicariance events. In the allozyme analysis, the Bayesian approach partitioned different populations into three clusters, with clusters I, II, and III mainly found in northern, central, and southern Taiwan, respectively. Morphologically, fish from north and south of the Tropic of Cancer had distinct numbers of lateral line scales and were separated into two morphs. The cohabitation of different mtDNA lineages with high allozymic and morphological similarities suggests that interbreeding amongst them is possible. Therefore, in spite of highly differentiated mtDNA, samples from different collecting sites should be considered a single species. Based on the current population distribution and levels of divergence, we propose that both orogenic activities and marine regression during glacial epoch were the two main forces shaping population differentiation of this species. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 161 , 613–632.     

Quantification of Flavonoid Compounds from Strawberry ( Fragaria ananassa) and Correlation Effects with Antioxidant Activities

The amounts of flavonoid (myricetin , quercetin and kaempferol), antioxidant contents ( total phenolic and total flavonoid) and antioxidant activities (DPPH and FRAP) were analyzed in strawberry. Quantitative analysis of conjugated flavonoid contents were obtained after different hydrolysis concentration and reaction period . The highest yields of myricetin and quercetin were found with 1.0M HCl and a reaction period of 0.5 hr, however , for kaempferol was 1.0M HCl and a reaction period of 1hr , respectively. In the study, we also estimated the correlation coefficient of TPC, TFC, DPPH and FRAP. In addition , a positive correlation was observed ( r = 0.980, P < 0.05) between TPC and TFC, TPC and TFC are correlated to the DPPH activity (r = 0.913, P < 0.05 and r = 0.899 , P < 0.05 , respectively) , and to the FRAP activity ( r = 0.958, P < 0.05 and r = 0.936, P < 0.05, respectively), respectively. These results pointed out that strawberry generally possesses a high level of antioxidant activities, which could be linked to the levels of phenolic compounds in the fruit.     

Waardenburg综合征Ⅱ型患者MITF基因突变分析

Waardenburg综合征(WS)是临床上常见的常染色体显性遗传性耳聋综合征, MITF基因突变与部分Waardenburg 综合征Ⅱ型(WS2)病例的发病有关。MITF属于碱性螺旋-环-螺旋亮氨酸拉链转录因子家族, 能调节酪氨酸酶基因, 参与黑色素细胞的分化。文章报道了1个携带MITF基因点突变的3代Waardenburg综合征Ⅱ型中国家系。先证者表现为先天性重度感音神经性聋、虹膜异色、面部雀斑; 其他家系成员除一名仅表现为先天性耳聋外, 均表现为颜面、上肢雀斑和/或早白发。患者可检测到c.639delA杂合突变, 该突变在MITF基因第7外显子上产生了终止密码子(p.I220X), 突变产生的截短的MITF蛋白没有DNA结合活性。该突变是WS2病例中第3个位于MITF第7外显子的突变, 尚未见报道。该突变与已报道的位于第7外显子其他两个突变仅相差1个碱基, 氨基酸改变十分相似, 但在表型上有显著差别, 提示遗传背景对WS临床表型有重要影响。     

Determining uptake of 'non-labile' soil cadmium by Thlaspi caerulescens using isotopic dilution techniques

We assessed the ability of several populations of the metal-hyperaccumulator species, Thlaspi caerulescens , to mobilize non-labile cadmium in soils historically contaminated by Pb/Zn mine spoil or sewage sludge. Radio- labile Cd was determined chemically as an ' E -value', [Cd _E ], and biologically as an ' L -value', [Cd _L ]. For comparison, chloride-extractable Cd, [Cd_chlor], was also determined using 1 M CaCl₂ as a single-step soil extractant. Values of [Cd _L ] were measured for six populations of T. caerulescens that varied substantially in their ability to assimilate soil Cd, and a non-accumulator species with a similar growth habit, Lepidium heterophyllum . Seeds were sown in soil spiked with ¹⁰⁹Cd and grown for 9–12 wk in a controlled environment room. Values of [Cd _L ] were determined from the specific activity of ¹⁰⁹Cd and concentration of Cd in the plant leaves. For the six soils studied, [Cd _E ] ranged from 4.9 to 49% of total soil Cd [Cd_T]. Values of [Cd _L ] were, in general, in close agreement with both [Cd _E ] and [Cd_chlor] and substantially less than [Cd_T]. However, [Cd _L ] showed no correlation with the concentration of Cd in plant tissue, [Cd_shoot]. This suggests that, in the soils studied, T. caerulescens did not mobilize non-labile soil Cd by producing root exudates or altering rhizosphere pH. The results imply that there may be significant restrictions to metal bioavailability, even to hyperaccumulator species, in heavily contaminated soils in which a large proportion of the metal may be present in 'non-labile' forms.     

温带林的片断化对冬季兽类丰富度的影响

1997 年至1999 年间, 在韩国智异山国家公园选取生境相似, 但片断化和未片断化不同的调查地。设置8 条2 km 长截线, 调查记录了黄鼬( Mustela sibirica) 、黄喉貂(青鼬) ( Martes lavigula) 、狗獾(Meles meles) 、豹猫( Felis bengalensis) 、野猪( Sus scrofa) 、獐( Hydropotes inermis) 、狍( Capreolus) 、朝鲜兔(Lepus coreanus) 和松鼠的数量, 并对影响动物数量的相关因子进行回归分析。结果表明, 8 块样地虽属两大类不同景观且具有相似植被特征, 但在片断化和未片断化中, 枯折木, 胸高直径(dbh)6～10 cm的树及50 cm的巨树密度, 树冠盖度及灌木被度均有明显差异。3 年内在8 块样地共记录到9种兽类在雪被上留下的足迹, 其中5 种兽的密度在片断化和未片断化生境中差异明显。9 种兽的渐近多元回归中, 6 种兽的密度同景观和植被变量密切相关, 但如果不增加当地生境条件, 则足迹链丰富度同植被构成的简单相关性表现得很微弱。在片断化和未片断化的不同景观林区, 对兽类的分布及其动态还要做进一步详细研究。     

太湖生态系统能量闭合特征及其影响因素

地表能量不闭合不仅限制了涡度相关观测数据在陆面模型发展和验证等应用性研究中的价值,还给生态系统CO2源汇特征辨析带来不确定性。基于太湖避风港站2012年涡度相关通量、辐射、气象和水温梯度观测数据,分析了太湖能量闭合的多尺度(小时、日和月)时间变化特征,阐述了大气稳定度、摩擦风速和湖风对太湖能量闭合状况的影响。结果表明:太湖小时尺度的能量闭合度为0.59,且昼夜差异较小;日尺度的能量闭合度为0.73,在内陆水体观测结果中处于中等水平;月平均能量闭合度呈现冬季高、夏季低的季节变化特征;年平均时太湖仍有27%的能量不闭合。因摩擦风速减小,太湖能量闭合度在大气极不稳定条件下要比弱不稳定条件下结果低0.3;对于太湖这类大型浅水湖泊,其能量闭合度全天都受动力湍流交换强度制约,能量闭合度随摩擦风速增大而显著提高;虽然湖风发生使太湖小时尺度的能量闭合度降低了0.1,但其影响在日尺度上并不明显。