Nocodazole-Resistant Mutants in Paramecium

The effect of the microtubule inhibitor nocodazole was studied on Paramecium and shown to arrest cell multiplication, depolymerize the internal microtubule network, and block the development of macro- and micronuclear spindles and of the cytospindle (a cortical microtubule array assembled during division). After ultraviolet mutagenesis, three mutants resistant to nocodazole, that is capable of continued growth in the presence of the drug, were isolated and shown to correspond to three nonallelic single-gene nuclear mutations. One ( noc ^r- 1 ) is semidominant while the other two ( noc ^r- 2 and noc ^r- 3 ) are recessive. Cytological and physiological studies of nocodazole's effects on the mutants demonstrate that their resistance is due neither to a lack of drug penetration nor to its degradation since, in each mutant in the presence of the drug, some microtubule networks are normal or subnormal while others remain affected as in wild-type cells. These are the first mutants resistant to microtubule depolymerizing drugs obtained in ciliates that provide a new tool for studying the assembly and dynamics of the diverse microtubule arrays in this type of organism.     

A comparative analysis of the diets of the Chough Pyrrhocorax pyrrhocorax and the Alpine Chough Pyrrhocorax graculus coexisting in the Alps

The diets of the Chough Pyrrhocorax pyrrhocorax and the Alpine Chough Pyrrhocorax graculus coexisting in the western Italian Alps have been compared by faecal analyses. A total of 1581 fresh droppings (405 of the Chough and 1176 of the Alpine Chough) were collected in the pastures of the Rhêmes Valley, Aosta, Italy, from June to November 1992 and analysed in the laboratory, and a mean volume percentage for each item was calculated. Both species were omnivorous, including animal, vegetable and mineral dietary fractions. There was no overlap in the vegetable part of the diet since the Chough fed virtually exclusively on Yellow Gagea Gagea fistulosa bulbs (dug out from the soil), which were not taken at all by the Alpine Chough. Conversely, the Alpine Chough fed on berries and hips from September to November, but these were virtually ignored by the Chough. Even though animal items were collected by both species, their preferences were different. In June, Alpine Choughs largely collected cranefly (Tipula) larvae whilst Choughs mainly fed on Lepidoptera larvae. From July onward, Alpine Choughs mainly consumed grasshoppers while Choughs also collected Tipula pupae, Lepidoptera and fly (Bibionidae) larvae and beetles (Scarabaeidae and Staphylinidae). Interspecific morphological and behavioural differences may be partly responsible for the segregation observed. Chemical composition and caloric contents of the food items suggest that the balance between costs of collecting and benefits of consuming may also contribute to diet differentiation. Both species took a broad spectrum of food, and there was no clear indication that the different population densities of the two Choughs in the Alps were directly correlated with diet, even though some data suggest that during autumn the Alpine Chough might have a diet better adapted to the high mountain environment than the Chough.     

Microsatellite loci transferability from Theobroma cacao to Theobroma grandiflorum

Theobroma grandiflorum (cupuassu) is an important fruit tree native to the Brazilian Amazon. Forty‐eight microsatellite loci developed for the congener Theobroma cacao were tested in cupuassu, and 29 (60.4%) produced robust alleles. The analyses of 216 cupuassu accessions using the 21 polymorphic microsatellite loci revealed a total of 113 alleles. The number of alleles per polymorphic locus ranged from two to 11, with an average of 5.38 alleles per locus. The average observed heterozygosity was 0.343, while the mean expected heterozygosity was 0.614. The successful transferability of T. cacao microsatellite primers to cupuassu was consistent with currently accepted phylogeny.     

Isospora Normanlevinei N. Sp. and Isospora Coluzzii N. Sp. (Apicomplexa: Eimeriidae) In Emberiza Cirlus (Cirl Bunting) (Passeriformes-Emberizidae)

ABSTRACT. The morphological characteristics of two new species of Isospora observed in Emberiza cirlus (Cirl Bunting) from Italy are reported. the oocysts of Isospora normanlevinei n. sp. are spherical or sub-spherical, with a smooth double-layered wall, and measure 24.2 times 23.7 (21.0-26.5 times 21.5-25.5) μm; each oocyst contains 2 to 10 polar granules. No micropyle or residuum was observed. the piriform sporocysts measure 19.4 times 11.2 (17.0-21.0 times 10.0-12.5) μm and contain a dispersed residuum. the Stieda body is flat; the substiedal body, with scattered clear and dark granules, may be either symmetrical or asymmetrical. the oocysts of I. coluzzii n. sp. are asymmetrical and rounded shape and measure 28.6 times 24.2 (25.0-31.5 times 21.5-26.0) μm. the oocyst has a double-layered wall and 2 to 3 polar granules. Neither micropyle nor residuum is present. the sub-ellipsoidal sporocyst, measuring 18.2 times 10.0(16.5-20.0 times 9.0-11.0) μm, has a dispersed sporocyst residuum. the Stieda complex is symmetrical.     

Geochemistry of Persististrombus latus Gmelin from the Pleistocene Iberian Mediterranean realm

De Torres, T., Ortiz, J.E., Arribas, I., Delgado, A., Julià, R. & Martín‐Rubí, J.A. 2009: Geochemistry of Persististrombus latus Gmelin from the Pleistocene Iberian Mediterranean realm. Lethaia, Vol. 43, pp. 149–163. In this paper the organic and inorganic geochemistry of fossil and extant Persististrombus latus are compared, together with other strombid species (Lentigo lentiginosus, Lobatus gigas, Strombus alatus, Lobatus raninus, Laevistrombus canarium and Tricornis latissimus). Using a large sample of well‐preserved fossil P. latus shells from the Mediterranean realm, we examined the warming period of sea water in the Middle Pleistocene. A mineralogical study of the shells demonstrates the continuous presence of calcite and a complex organic matter distribution, which was well preserved in many cases, thereby making the U/Th dating of strombid shells unreliable. U/Th analysis of coral samples and amino acid racemization dating of pelecypod shells confirmed that P. latus entered the Mediterranean realm in MIS 7 and 5. The oscillations of the δ¹⁸O values reflect annual growth periods and provide a mixing of the first signal record (primary growth) and successive overgrowths. □Amino acid racemization, Mediterranean Sea, Persististrombus latus, shell mineralogy, U/Th, δ¹⁸O.     

Epixenosomes: Peculiar Epibionts of the Hypotrich Ciliate Euplotidium Itoi Defend Their Host Against Predators

ABSTRACT. Euplotidium itoi harbors on its dorsal surface peculiar episymbionts (referred to as epixenosomes) equipped with a complex extrusive apparatus. In the laboratory. E. itoi stocks without epixenosomes behave and reproduce like symbiotized stocks. the hypothesis that epixenosomes play a defensive role against predators was tested by comparing the behavior of Litonotus lamella when preying upon Euplotes crassus, E. itoi without epixenosomes. and E. itoi with epixenosomes. Litonotus discharges its toxicysts upon direct-cell-to cell contact, and paralyzes the three types of prey with the same efficiency. Nevertheless, Litonotus can ingest Euplotes, Euplotidium without epixenosomes, and to a certain extent, Euplotidium with epixenosomes whose ejecting capability has been inhibited. while it never eats Euplotidium with unaltered epixenosomes. In each prey-type, about 60% of the individuals attacked by Litonotus toxicyst discharge are able to recover their normal behavior once transferred into pure sea water. This percentage for E. itoi with epixenosomes that are never eaten by the predator corresponds to the probability of survival. This probability is lower for the other two prey-types in which the prey engulfed by the predator do not have the chance to recover. These data support the hypothesis and suggest the involvement of the epixenosome's ejecting apparatus in a defensive function.     

Revision and cladistic analysis of Isoctenus and description of a new neotropical genus (Araneae,Ctenidae, Cteninae)

A cladistic analysis was applied to test the monophyly of the genus Isoctenus. The data matrix comprised 28 taxa scored for 53 morphological and two behavioural characters. The analysis resulted in two equally parsimonious trees of 89 steps. The strict consensus was used to discuss the relationships of Isoctenus and related Cteninae genera. Ctenopsis Schmidt is synonymized with Isoctenus. Isoctenus foliifer Bertkau, I. strandi Mello‐Leitão, I. eupalaestrus Mello‐Leitão, I. janeirus (Walckenaer), I. coxalis (Pickard‐Cambridge), I. corymbus Polotow, Brescovit & Pellegatti‐Franco and I. malabaris Polotow, Brescovit & Ott are maintained in Isoctenus. Four species currently included in Ctenus are transferred to Isoctenus: I. griseolus (Mello‐Leitão) comb. nov., I. taperae (Mello‐Leitão) comb. nov., I. herteli (Mello‐Leitão) comb. nov. and I. minusculus (Keyserling) comb. nov. The following specific names are synonymized: Ctenus sanguineus Walckenaer, C. semiornatus Mello‐Leitão and Ctenopsis stellata Schmidt with Isoctenus janeirus (Walckenaer), Ctenus mourei Mello‐Leitão with Isoctenus herteli (Mello‐Leitão) and Ctenus pauper Mello‐Leitão with Isoctenus strandi Mello‐Leitão. Isoctenus sigma Schenkel, described from French Guiana, is transferred to Ctenus. Four species are newly described: Isoctenus areia sp. nov. from Paraíba, Brazil, I. charada sp. nov. and I. segredo sp. nov. from Paraná, Brazil, and I. ordinario sp. nov. from south and south‐eastern Brazil and north‐eastern Argentina. Isoctenus latevittatus Caporiacco is considered species inquirenda. Parabatinga gen. nov. is proposed to include Ctenus brevipes Keyserling. The following synonymies are established: Ctenus taeniatus Keyserling, C. tatarandensis Tullgren, C. anisitsi Strand, C. atrivulvus Strand, C. mentor Strand, C. brevipes brevilabris Strand, Isoctenus masculus Mello‐Leitão and Ctenus birabeni Mello‐Leitão with Parabatinga brevipes (Keyserling) comb. nov. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 155 , 583–614.     

Changes in fish assemblages in catchments in north‐eastern Spain: biodiversity,conservation status and introduced species

1. North‐eastern Spain is a hot spot for the introduction of alien fish species, and its native fish fauna is one of the most endangered worldwide. We used an extensive data set from 2002 to 2003 and historical information from the area to characterize fish diversity and establish conservation priorities in river catchments. 2. Diversity indices were used to characterize fish diversity at the basin scale. An index of conservation status was applied for each species, which considers the occurrence, abundance and endemicity of each taxon. We used indirect ordination methods to test the relationship among basin features and to identify those variables most correlated with each other. To identify physical, biotic and environmental characteristics that seem to make a basin particularly susceptible to invasion, we performed a step‐wise multiple regression to examine the relationship between the number of native, translocated and introduced fish species (including the original native species richness of each basin), and landscape variables. 3. Over a period of approximately 50 years, the mean range size of native fish species has decreased by 60%. The greatest decline occurred in Gasterosteus gymnurus, Anguilla anguilla and Salaria fluviatilis, for which species over 75% of the original distribution area has been lost. The species with the highest conservation index were Gasterosteus gymnurus and Salaria fluviatilis. 4. Basin area and the catchment type explained 70% of variation in native species richness, whereas the number of dams and basin area accounted for more than 80% of variation in the number of introduced species. 5. The original native species richness and the number of introduced species at basin scale were not related, and thus there was no evidence of “biotic resistance” to invasion. The restoration of natural hydrologic processes and the development of specific management tools to protect native species, such as the prioritization of areas for fish conservation and the eradication of local populations of exotic species, are required to restore native fish fauna in these catchments.