Removal of two pathogenic scuticociliates Miamiensis avidus and Miamiensis sp. using cells or culture filtrates of the dinoflagellate Alexandrium andersonii

Scuticociliatosis, which is caused by parasitic protistan pathogens known as scuticociliates, is one of the most serious diseases in marine aquaculture worldwide. Thus, elimination of these ciliates is a primary concern for scientists and managers in the aquaculture industry. To date, formalin and other toxic chemicals have been used as anti-scuticociliate agents, but issues regarding their secondary effects often arise. Consequently, development of safer methods is necessary. To find out a safe method of controlling scuticociliate populations in aqua-tanks or small-scale natural environments, cultures of 14 phototrophic dinoflagellates were tested to determine whether they were able to control populations of the common scuticociliates Miamiensis avidus and Miamiensis sp. isolated from Korean waters. Among the dinoflagellates tested, both cells and culture filtrates of Alexandrium andersonii effectively killed M. avidus and Miamiensis sp. The minimal concentration of cells and equivalent culture filtrates of A. andersonii to kill all M. avidus cells within 48 h of incubation was ca. 2500 and 4500 cells ml⁻¹, respectively; whereas those needed to kill all Miamiensis sp. cells were ca. 1000 and 4500 cells ml⁻¹, respectively. It was estimated that 1 m³ of the stock culture containing 20,000 A. andersonii cells ml⁻¹ could eliminate all M. avidus cells in 7 m³ of waters within the aqua-tanks on land and all Miamiensis sp. cells in 19 m³ of waters within 48 h. None of the brine shrimp Artemia salina nauplii incubated with concentrations of 50–4500 A. andersonii cells ml⁻¹ for 24 h was dead. Furthermore, none of the flounder Paralichthys olivaceus juveniles incubated with a mean concentration of ca. 2280 A. andersonii cells ml⁻¹ for 96 h was dead. Therefore, A. andersonii cultures may be used as a safe biological method for controlling populations of scuticociliates and can replace toxic formalin. The results of this study provided the basis for developing the method to control scuticociliate populations and understanding interactions between scuticociliates and phototrophic dinoflagellates in marine ecosystems.     

Models for Trypanosoma evansi (surra), its control and economic impact on small-hold livestock owners in the Philippines

Simple demographic and infectious disease models of buffaloes and other domestic hosts for animal trypanosomosis (surra) caused by Trypanosoma evansi were developed. The animal models contained deterministic and stochastic elements and were linked to simulate the benefit of control regimes for surra in village domestic animal populations in Mindanao, Philippines. The impact of the disease on host fertility and mortality were key factors in determining the economic losses and net-benefit from the control regimes. If using a high (99%) efficacy drug in surra-moderate to high risk areas, then treating all animals twice each year yielded low prevalence in 2 years; targeted treatment of clinically sick animals, constantly monitored (monthly), required 75% fewer treatments but took longer to reach a low prevalence than treating all animals twice each year. At high drug efficacy both of these treatment strategies increased the benefit over untreated animals by 81%. If drug efficacy declined then the benefit obtained from twice yearly treatment of all animals declined rapidly compared with regular monitoring and targeting treatment to clinically sick animals. The current control regimen applied in the Philippines of annual sero-testing for surra and only treating sero-positive animals provided the lowest net-benefit of all the control options simulated and would not be regarded as effective control. The total net-benefit from effective surra control for a typical village in a moderate/high risk area was 7.9 million pesos per annum (US $158,000). The value added to buffaloes, cattle, horses, goats/sheep and pigs as a result of this control was US $88, $84, $151, $7, $114 per animal/year, respectively.     

A Growth Curve Analysis for Bulls Tested at Station

Data on 2712 bulls tested at station were analysed to study the effect of certain external variables on growth traits of bulls. Most of the animals were Ayrshires (2136). Otherwise Finncattle bulls and Frisian bulls were involved. The testing covers the interval 60–365 days of age, although in part of the data the period is 30–365. Bulls were weighted every 30th day (between 1965 and 1970), or at the ages of 60 and 180 days, and thereafter every 30 days up to the age of 365 days (between 1971 and 1977). Also birth weight was available for 1250 calves. Feeding and general treatment of bulls at station was as uniform as possible for all animals. Conseqúently it can be assumed that effects of non-genetic factors on the growth traits of bulls are minimized. One of the objectives of this study was to compare the growth curves for the three breeds. In our data measurements at certain time-points have dropped out during the course of data collection. Therefore we study the influence of deleting measurements. We also consider the problem of influential measurements at both the design level and the inference level. Several types of growth curves are fitted to the data in order to find the most appropriate model.     

Structure and Evolution of the Mitochondrial DNA Complete Control Region in the Lizard Lacerta dugesii (Lacertidae, Sauria)

Abstract We sequenced the complete control region (CR) and adjacent tRNAs, partial 12S rRNA, and cytochrome b (over 3100 bp) from eight individuals of Madeiran wall lizards, Lacerta dugesii, from four distinct island populations. The tRNAs exhibit a high degree of intraspecific polymorphisms compared to other vertebrates. All CR sequences include a minisatellite that varies in length between populations but is apparently fixed within them. Variation in minisatellite length appears between populations separated by apparently very short evolutionary time spans. Many motifs identified in the CR of other vertebrates are not highly conserved, although conserved blocks are identifiable between the few published reptile CR sequences. Overall there are extensive differences in the internal organization of the reptile CR compared to the more widely studied mammals and birds. Variability in the CR is lower than in cytochrome b, but higher than in 12S rRNA. Phylogenetic analysis of these sequences produces a well-resolved estimate of relationships between populations.     

白鱼线粒体DNA控制区结构和种群遗传多样性分析

用特异性引物对白鱼(Anabarilius grahami)DNA进行PCR扩增,获得了白鱼线粒体DNA控制区基因全序列(930bp)。控制区T、C、A和G碱基组成为29.8%、22.5%、33.0%和14.7%。对照其他已报道的鱼类控制区结构,对白鱼控制区结构进行了分析,识别了其终止序列区、中央保守区和保守序列区,找到了终止相关的序列TAS以及保守序列(CSB-F、CSB-D、CSB-1、CSB-2、CSB-3)。同时运用DNA分析软件对白鱼一个驯养种群(中国科学院昆明动物研究所珍稀鱼类繁育中心)及两个自然地理种群(江川县明星鱼洞、江川县牛摩村)进行了遗传多样性分析。结果显示:两个自然种群存在较强基因交流,未出现遗传分化;人工驯养种群遗传多样性最高,种群复壮程度较好。     

Interspecific competition between two species of the bean weevil

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Contributions from the Entomological Laboratory, Kyoto University, No. 110.     

Shannon's Measure and its Use in the Analysis of Cancer Data

In this paper, Shannon's measure of uncertainty is explored in the analysis of cancer data. The term ‘cancer diversity’ is defined and its potential application is illustrated.     

Nonparametric,GINI-like Measures of Location and Dispersion

GINI's nonparametric measure of dispersion, defined as the mean of (n/2) pairs of a sample of n measurements, is modified for triplets. That way a GINI-like measure of location G* is defined as the mean of the (n/3) triplet medians, and a GINI-like measure of dispersion is defined as the mean of the (n/3) triplet ranges. G* and g* are less sensitive to outlier measurements than are the corresponding parametric measures, arithmetic mean and standard deviation, in small samples. Applications and application-related problems are discussed.