Localization and identification of the receptors by electron micrographic and ablation studies

Asexual reproduction (fissioning) in the planarian Dugesia dorotocephala is socially controlled through a cephalic mechanism; isolation releases fissioning, grouping inhibits it; decapitation releases it even in grouped subjects. Experiments were performed to confirm previous indications that direct contact is involved in the sensing of cohorts; the partial release of fissioning in grouped planarians by introduction of a chemically inert lubricant (0.1% purified agar) into the habitat water further confirms the necessity of intimate contact between the sensors and bodily surfaces of the sensed cohorts. Further experiments, correlating electron microscopic observations with the release of fissioning by various selected surgical ablations, reveal the pertinent sensors to be clumps of neural cilia concentrated in the cephalic margins. Comparable structures occur in the chemoreceptors of catfish, lamprey, and honey bee as well as in the olfactory epithelium of mammals.     

Genetic Differentiation in Tetranychus Urticae (Acari: Tetranychidae): polymorphism,host races or sibling species?

Based on allozyme electrophoresis at the Pgm locus and nuclear ribosomal DNA (ITS2) sequences, we studied the genetic variation of the two-spotted spider mite Tetranychus urticae Koch collected on rose bay, Nerium oleander L. (Apocynaceae), from several localities around the Mediterranean basin. In addition, we compared these results with those of Navajas et al. (1998) and Tsagkarakou (1997) who collected from several other host plants from the Mediterranean. In the western part of this area (Spain, France, Tunisia), we found the individuals collected from rose bay to be clearly genetically differentiated from other samples. No evidence of such host-associated differentiation was detected in the eastern Mediterranean (Italy and Greece). The genetic differentiation of mites collected on rose bay was investigated further by studying the reproductive incompatibilities between populations in Greece and in France and a laboratory strain reared on bean, Phaseolus vulgaris, in France. Reciprocal crosses performed between these strains revealed variable levels of incompatibility, spanning from partial to complete reproductive isolation. In all cases incompatibility was asymmetric. We designed a test based on double-mating to establish the fertilization status of females in fully incompatible crosses. These crosses showed that the females had been inseminated, which suggests that the barrier to reproduction is not of a prezygotic behavioral nature. The data raises the question of the relative role of ecological factors (host plant) and geographical distance, in the ongoing differentiation process potentially leading to speciation.     

Effects of the preadatorDugesia dorotocephala [Tricladida: Turbellaria] on selected nontarget aquatic organisms: Laboratory bioassay

The effects ofDugesia dorotocephala (Woodworth), a proven predator of aquatic Diptera, on 17 species of nontarget aquatic organisms were determined under controlled laboratory conditions. Only 3 of the nontarget organisms,Aeolosoma sp.,Cyclops sp. andToxorhynchites amboinensis (Doleschall), were significantly affected byD. dorotocephala. No significant difference in prey preference was found when planaria were maintained together with the target organism,Aedes aegypti, and the 3 adversely affected nontarget organisms. Results of this initial evaluation indicate thatD. dorotocephala is potentially safe to integrate as a biological control with most nontarget aquatic organisms tested. The opinions or assertions contained herein are the private views of the author(s) and are not to be construed as official or as reflecting the view of the Department of the Army or the Deparmtment of Defense.     

Laboratory culture and taxonomy of two species ofPedobesia (Bryopsidales,Chlorophyceae) in Japan

The morphology ofPedobesia lamourouxii andDerbesia ryukyuensis, both collected in Shimoda and the adjacent areas in central Japan, was studied from field specimens and laboratory cultures. Specimens which had the same morphology as EuropeanP. lamourouxii produced stephanokont zoospores which developed into either prostrate filaments or expanded discoidal thalli similar to those described by Feldmann and Codomier (1974) and Feldmannet al. (1975). Erect filament identical with the thallus found in nature developed directly from prostrate filaments. The specimens which had morphology similar to that ofDerbesia ryukyuensis described by Yamada and Tanaka (1938) also produced stephanokont zoospores which developed similarly to those ofP. lamourouxii. This species is, therefore, a member ofPedobesia, and it is made a new combinationP. ryukyuensis (Yamada et Tanaka) Kobara et Chihara, comb. nov.     

Feedback cue and switching characteristics

Asexual reproduction (fissioning) in planarians is controlled by group size; increased group size suppresses fissioning, isolation releases it. This effect is mediated through the brain; social stimulation from cohorts causes the brain to inhibit the segmental plexus fissioning system from initiating the events of fissioning. Experiments were conducted to elucidate (1) the stimulus cue conveying information regarding cohort number and (2) the switching characteristics of the control system. The results of these show that the social stimulus responsible for the effect involves neither vision nor discharge of pheromonal substances into the habitat; the sensory event apparently involves direct contact and chemoreceptive, as well as tactile, modalities. The switching characteristics (graduated response, long release time, short reinstatement time) found for the brain inhibitory system agree with those expected from the mathematical model derived for a simple neurohormonal control system in which it is postulated that social stimulation causes neurosecretory cells of the brain to release a fissioning inhibitory hormone (FIH) that inhibits the segmental plexus fissioning (SPF) system from initiating fissioning.     

Tilletiopsis derxii, Tilletiopsis oryzicola and Tilletiopsis penniseti, three new species of the ustilagionomycetous anamorphic genus Tilletiopsis isolated from leaves in Thailand

Four strains of ballistoconidium-forming yeast-like fungi (K-95, K-125, K-132 and K139), isolated from plants collected in Bangkok, Thailand, were assigned to the genus Tilletiopsis based on morphological and chemotaxonomical characteristics. On the basis of sequence data of 18S rDNA and the D1/D2 region of 26S rDNA, strains K-95, K-125 and K-132 were close to T. flava and T. fulvescens, and strain K-139 each formed related to T. minor. DNA-DNA reassociation experiments with related species revealed that strains K-125, K-132 and K-139 each formed a new and distinct species whereas strain K-95 was identified as T. flava. Tilletiopsis derxii Takashima et Nakase sp. nov. (JCM 10217^T; K-125), Tilletiopsis oryzicola Takashima et Nakase sp. nov. (JCM 10218^T; K-132), and Tilletiopsis penniseti Takashima et Nakase sp. nov. (JCM 10216^T; K-139) are the names proposed for the new taxa.     

铬黄圆痕叶蝉属的订正及圆痕叶蝉族巴西二新属二新种描记（半翅目：叶蝉科）

基于比较形态学对曾归入圆痕叶蝉亚科铬黄圆痕叶蝉属Chromagallia的8个有效种（C. saucia (St?l), C. flavofasciata (St?l), C. longistilata (Coelho & Dutra), C. carvalhoi Gon?alves et al., C. lamasi Gon?alves et al., C. lanceolata Gon?alves et al., C. paraguayensis Gon?alves et al.和C. zanolae Gon?alves et al.）进行了订正,明确了该属的范围仅限于具有黄斑的3个种（C. flavofasciata (St?l), C. longistilata (Coelho & Dutra) 和C. rodriguesoi sp. nov.）,对该属进行了重新描述,并修订了鉴别特征。此外,对模式种C. flavofasciata 进行了重新描记,首次提供了C. longistilata的雌性生殖器图,并作了描记。把曾归入铬黄圆痕叶蝉属Chromagallia具有红斑的6个种移出并新建了2个新属：Rubragallia 和Neorubragallia,其中Rubragallia 包括R. saucia (St?l) n. comb.和R. paraguayensis (Gon?alves et al.) n. comb., Neorubragallia包括N. lamasi (Gon?alves et al.) n. comb., N. lanceolata (Gon?alves et al.) n. comb., N. zanolae (Gon?alves et al.) n. comb., N. carvalhoi (Gon?alves et al.) n. comb. 和N. mervini sp. nov.。文中提供了3个属的分种检索表,并对不同种的分类地位及3个属的划分进行了讨论。     

Macrosiagon deuvei n. sp. (Coleoptera: Ripiphoridae) from the French Eocene amber

Macrosiagon deuvei n. sp., the second fossil representative of this extant genus of Ripiphoridae: Ripiphorinae: Macrosiagonini is described from the lowermost Eocene amber of Oise (France). The new species is compared with the extant species of the genus. Taxonomic position of other two fossil representatives of the family described from France by Perrichot et al. (2004) is discussed. The genus Paleoripiphorus Perrichot et al. 2004 is tentatively transferred from Ripiphorinae to Ripidiinae.     

甘蔗内生解淀粉芽孢杆菌CGB15的分离、鉴定及生防活性

真菌病害占作物病害种类的一半以上,病原真菌是目前已知种类最多的作物病原菌。从作物根际与/或体内分离筛选具有生防活性的微生物,并应用于病害的防控,是除作物品种改良与化学防治外的另一种高效的病害防控策略。【目的】本研究拟筛选并分离鉴定对重要作物病原真菌具有拮抗作用的甘蔗内生细菌,为开发生物防治作物真菌病害新策略提供理论依据。【方法】采用平板对峙法初步筛选对病原真菌具有拮抗能力的甘蔗叶片内生细菌,通过16SrRNA基因测序鉴定其种属;进一步检测候选拮抗内生细菌对甘蔗鞭孢堆黑粉菌(Sporisorium scitamineum)致病发育过程关键步骤：有性配合/菌丝生长、冬孢子萌发的抑制率,田间试验检测其对甘蔗鞭黑穗病的防治效果;检测候选拮抗内生细菌对稻梨孢菌(Pyricularia oryzae)附着胞形成、离体叶片及盆栽条件下叶片病斑形成的抑制作用。【结果】分离自甘蔗叶片的细菌菌株,编号为CGB15,经分子鉴定为解淀粉芽孢杆菌(Bacillus amyloliquefaciens)。CGB15菌株能有效抑制甘蔗鞭孢堆黑粉菌有性配合/菌丝生长,对峙培养条件下使真菌菌落呈现光滑;抑制冬孢子萌发,...     

Estimation of primary production using five different methods in a Spartina alterniflora salt marsh

The aboveground production of Spartina alterniflora in a salt marsh in Barataria Bay, Louisiana, USA was estimated using five different harvest methods: peak standing crop (PSC), Milner-Hughes, Smalley, Wiegert-Evans, and Lomnicki et al., and a non-destructive method based on measurement of stem density and longevity. Annual production estimates were 831 ± 41, 831 ± 62, 1231 ± 252, 1873 ± 147 and 1437 ± 96 g dry wt m^–2 for each method, respectively. The average longevity of individually tagged young shoots was 5.2 ± 0.2 months, equivalent to an annual turnover rate of 2.3 crops per year. Among the five methods, Wiegert-Evans and Lomnicki et al. were considered more accurate than the other three because they corrected for mortality losses between sampling times. The Lomnicki et al. method was preferred over the Wiegert-Evans method because of its greater simplicity.     

Seeing the forest beyond the trees

In a recent paper (Mitchard et al. 2014, Global Ecology and Biogeography, 23 , 935–946) a new map of forest biomass based on a geostatistical model of field data for the Amazon (and surrounding forests) was presented and contrasted with two earlier maps based on remote‐sensing data Saatchi et al. (2011; RS1) and Baccini et al. (2012; RS2). Mitchard et al. concluded that both the earlier remote‐sensing based maps were incorrect because they did not conform to Mitchard et al. interpretation of the field‐based results. In making their case, however, they misrepresented the fundamental nature of primary field and remote‐sensing data and committed critical errors in their assumptions about the accuracy of research plots, the interpolation methodology and the statistical analysis. By ignoring the large uncertainty associated with ground estimates of biomass and the significant under‐sampling and spatial bias of research plots, Mitchard et al. reported erroneous trends and artificial patterns of biomass over Amazonia. Because of these misrepresentations and methodological flaws, we find their critique of the satellite‐derived maps to be invalid.     

Production of presumptive humoral haematopoietic regulators in canine cyclic haematopoiesis

Abstract. Conditioned media (CM) were prepared according to previously published techniques from the bone marrow of dogs with cyclic haematopoiesis (CH). CM prepared from day 9 marrows inhibited mouse bone marrow CFU-s proliferation rate while CM from day 10 marrows were stimulatory and also contained an erythroid stimulating factor which appeared to be erythropoietin. In addition a highly significant trend from CM containing CFU-s inhibitory materials to media with CFU-s stimulatory activity was observed through cycles day 1 to 8. These studies further support the concept that CH is due to a defect in factors controlling stem cell proliferation and suggest that a major event occurs in CH dog marrow on days 9 and/or 10 of the cycle. Bone marrow transplantation studies (Dale & Graw, 1974; Weiden et al., 1974; Jones et al., 1975b) have indicated that canine cyclic haematopoiesis (CH) is probably due to a disorder in the multipotential stem cells. Morphological evidence (Scott et al., 1973) and the almost synchronous cycling of CFU-e, CFU-c and diffusion chamber progenitor cells (DCPC) (DUM et al., 1977, 1978a, b) lend support to such a theory. However, efforts to identify the mechanisms controlliig multipotential stem cell proliferation in dogs have been handicapped by the lack of suitable techniques to study these cells in the canine. Recently, Wright and co-workers (Wright & Lord, 1978, 1979; Wright et al., 1979; Lord et al., 1979), on the basis of previous observations (Frindel et al., 1976; Frindel & Guigon, 1977), described the preparation of species non-specific, bone marrow conditioned media (CM) which are capable of influencing the proliferation rate of murine colony forming units-spleen (CFU-s). The studies now reported were designed to determine if CM prepared from canine CH marrow would influence the proliferation rate of murine bone marrow CFU-s. The results indicate that a major event, possibly related to the in vivo control of stem cell proliferation in dogs with CH, occurs on days 9–10 of the cycle; day 1 being the first day when the peripheral blood neutrophil count falls below-1600 mm³.     

植物根际益生细菌代表性菌株贝莱斯芽孢杆菌FZB42对松材线虫的抑杀性

[目的]由松材线虫导致的松树萎蔫病是松树的毁灭性病害,也是我国最主要的林业病害之一.本研究测评了在农业上广泛使用的、我国微生物肥料行业主要菌种资源之一——贝莱斯芽孢杆菌,对松材线虫的潜在抑杀性能.[方法]选用贝莱斯芽孢杆菌的代表性菌株FZB42为材料,测定对不同条件下的菌液上清、不同菌株的菌液上清、细菌素plantaz...     

DEVELOPMENT AND DECLINING OF RESISTANCE IN DIAMOND BACK MOTH PLUTELLA XYLOSTELLA L. RESISTANT STRAINS SELECTED BY DIMEHYPO AND CARTAP*

Abstract Two resistant strains of diamond back moth Plutella xylostella L. were treated with dimehy-po and cartap in succession, The susceptible strain had never contacted with any insecticieds since reared in the in sectary. The rearing method by using vermiculite and radish seedling was discribed by Chen et al. (1990) and Liuet al. (1993). Comparison between reared strains and field strain did not display any difference in biological characteristics. The resistance reached 178 fold in dimehypo resistant strain in F₈₅, and 87 fold in cartap resistant strain in F₈₀, Two high level resistant strains had formed. After termination of selection, the resistance declined from 167 to 57 fold in dimehypo resistant strain and from 74 to 16 fold in cartap resistant strain within five generations. The resistance of diamond back moth to the two insecticides was unstable at high level, but could be steady at quite lower degree for a long time. It seemed impossible to regain the same sensitivity as before selection for the two resistant strains after resistance declining.     

Cetacean morbillivirus: A Land-to-Sea Journey and Back?

<正>Cetacean morbillivirus(CeMV), the most relevant pathogen impacting the health and conservation of several already threatened cetacean populations worldwide(Van Bressem et al. 2014), has shown in recent years an apparently increased tendency to cross ‘‘interspecies barriers' '(Jo et al. 2018 a), thereby giving rise to disease and mortality outbreaks in free-ranging dolphins and whales     

Bordetella adenylate cyclase toxin interacts with filamentous haemagglutinin to inhibit biofilm formation in vitro

Bordetella pertussis, the causative agent of whooping cough, secretes and releases adenylate cyclase toxin (ACT), which is a protein bacterial toxin that targets host cells and disarms immune defenses. ACT binds filamentous haemagglutinin (FHA), a surface‐displayed adhesin, and until now, the consequences of this interaction were unknown. A B. bronchiseptica mutant lacking ACT produced more biofilm than the parental strain; leading Irie et al. to propose the ACT‐FHA interaction could be responsible for biofilm inhibition. Here we characterize the physical interaction of ACT with FHA and provide evidence linking that interaction to inhibition of biofilm in vitro. Exogenous ACT inhibits biofilm formation in a concentration‐dependent manner and the N‐terminal catalytic domain of ACT (AC domain) is necessary and sufficient for this inhibitory effect. AC Domain interacts with the C‐terminal segment of FHA with ～650 nM affinity. ACT does not inhibit biofilm formation by Bordetella lacking the mature C‐terminal domain (MCD), suggesting the direct interaction between AC domain and the MCD is required for the inhibitory effect. Additionally, AC domain disrupts preformed biofilm on abiotic surfaces. The demonstrated inhibition of biofilm formation by a host‐directed protein bacterial toxin represents a novel regulatory mechanism and identifies an unprecedented role for ACT.     

Two species of Ergasilidae (Copepoda: Poecilostomatoida) parasitic on the gills of Mugil cephalus Linnaeus (Pisces: Teleostei), with proposition of a new genus Dermoergasilus

A new genus of Ergasilidae (Dermoergasilus) is proposed to accommodate Ergasilus amplectens Dogiel et Akhmerov, 1952; E. coleus Cressey, 1970; and E. semicoleus Cressey, 1970. Dermoergasilus amplectens (Dogiel et Akhmerov, 1952) and Nipergasilus bora (Yamaguti, 1939) are redescribed based on the specimens recovered from the gills of Mugil cephalus L. collected in Kojima Bay, Okayama Prefecture, Japan.     

The characteristics of nutrient removal and inhibitory effect of Ulva clathrata on Vibrio anguillarum 65

To investigate the ecological effect of macroalgae on de-eutrophication and depuration of mariculture seawater, the variation of dissolved inorganic nitrogen (DIN) and phosphate (DIP), the amount of Vibrio anguillarum, and total heterotrophic bacteria in Ulva clathrata culture, as well as on the algal surface, were investigated by artificially adding nutrients and V. anguillarum strain 65 from February to April 2006. The results indicated that U. clathrata not only had strong DIN and DIP removal capacities, but also showed a significant inhibitory effect on V. anguillarum, although not reducing the total heterotrophic bacteria. Vibrio anguillarum 65 dropped from 5∼8 × 10⁷ cfu mL⁻¹ to 10 cfu mL⁻¹ (clone-forming units per mL) in 10 g L⁻¹ of fresh U. clathrata culture within 2 days; i.e., almost all of the Vibrios were efficiently eradicated from the algal culture system. Our results also showed that the inhibitory effect of U. clathrata on V. anguillarum strain 65 was both DIN- and DIP-dependent. Addition of DIN and DIP could enhance the inhibitory effects of the algae on the Vibrio, but did not reduce the total heterotrophic bacteria. Further studies showed that the culture suspension in which U. clathrata was pre-cultured for 24 h also had an inhibitory effect on V. anguillarum strain 65. Some unknown chemical substances, either released from U. clathrata or produced by the alga associated microorganisms, inhibited the proliferation of V. anguillarum 65.     

Toxicology of planarians

Potential advantages of using planarians such as Dugesia dorotocephala (Woodworth) to assay a number of different kinds of toxic effects are illustrated by our experiments on neurotoxicity of nicotine, developmental neurotoxicity and behavioral teratogenesis of methylmercuric chloride (MMC), and carcinogenesis of Cd and tetradecanoyl-phorbol-acetate (TPA). Various concentrations of nicotine in the culture water in which planarians were maintained produced acute neurotoxic effects, evident as disturbances in locomotor and fissioning behavior; planarians also acquired tolerance to nicotine. Behavioral teratogenesis in planarians is illustrated by the effect of subteratogenic concentrations of MMC on regeneration of the brain and behavior of decapitated specimens. Despite normal appearance of heads and brains of MMC-treated regenerates, significant deficits were noted in righting response, locomotion, and prey-catching behavior. EM observations revealed quantitative deficits in brain synapses of MMC-treated regenerates. Exposure to the carcinogens Cd and TPA produced a single kind of neoplastic tumor, a malignant reticuloma, in 76% of specimens treated jointly with sublethal concentrations of both chemicals. Toxicological responses of planarians can be compared to those of vertebrates.     

Genetic divergence in Northamerican freshwater planarians of the Dugesia dorotocephala group (Turbellaria, Tricladida, Paludicola)

The genetic differentiation between the members of the Dugesia (Girardia) dorotocephala group was analyzed by means of multilocus electrophoresis, and comared to that of another planarian secies, D. tahitiensis, also belonging to the subgenus Girardia. The species examined were: D. dorotocephala s.s (2n = 16), D. arizonensis (2n = 8), D. jenkinsae (2n = 8), and the above mentioned D. tahitiensis (2n = 16). The former three species inhabit North America, and show different proportion of fissiparous and sexual individuals; the latter species inhabits Polynesia and is fully asexual. A total of 11 enzyme loci were genetically analyzed: Mdh-1, Mdh-2, Zdh-1, Idh-2, G3pdh, Got-1, Ck, Pgm-2, Ada, Mpi, and Gpi. Low values of observed mean heterozygosity per locus (Ho) were found in the populations studied, ranging from 0 to 0.18 (average 0.08. In asexual populations (except that of D. tahitiensis) fixed heterozygosity was observered in all the individuals for 1 or 2 loci. The genetic divergence between the species examined is very high, with many loci showing discriminating alleles in different taxa (Nei's genetic distance varies from 0.871 to 1.759). The populations of D. dorotocehala s.s., on the contrary, appear to be genetically quite homogenous average D= 0.019), and the genetic distance values are apparently unrelated to their geographic location and to their way of reproduction. The genetic distance between D. tahitiensis, a species not included in the D. dorotocephala group and D. dorotocephala s.s. is 1.314 and hence similar to the D value between two members of;he dorotocephala group: D. dorotocephala and D. jenkinsae (D = 1.303). The genetic relationships among the populations studied were established by UPGMA cluster analysis and multidimensional scaling. The descendence of the North American species with 2n = 8 from a dorotocephala-like ancestor with 2n = 16 is considered. It is suggested that the latter, as well as a tahitiensis-like line, also having 2n = 16, have originated from a common ancestor by geographic isolation.