Heterozostera tasmanica (Martens ex aschers.) den Hartog in Chile

A 1.2 km² meadow of Heterozostera tasmanica (Martens ex Aschers.) den Hartog was found at Pto. Aldea, Bahia Tongoy, 60 km south of Coquimbo, 30°S on the coast of Chile. This provides documented evidence of seagrass occurrence on the west coast of South America. Since H. tasmanica is widespread throughout southern Australia, the Chilean stock represents a highly disjunct population. It appears from several growth parameters (density, leaf biomass, leaf area index, specific leaf area, δ ¹³C) that the H. tasmanica meadow at Pto. Aldea is very similar to those found in other parts of the world.     

Lipid components of the seagrasses Posidonia australis and Heterozostera tasmanica as indicators of carbon source

The component hydrocarbons, sterols, alcohols, monocarboxylic, α, ω-dicarboxylic and ω-hydroxy acids of the seagrasses Posidonia australis and Heterozostera tasmanica and a sample of P. australis detritus are reported. The fresh leaves of P. australis and P. australis detritus are characterized by a distinctive distribution of solvent-extractable long-chain monocarboxylic, α, ω-dicarboxylic and ω-hydroxy acids. This distinctive pattern should enable these lipid components along with other distinctive components to be used as chemical markers of the seagrass P. australis. H. tasmanica is characterized by (1) higher relative concentrations of 16:2ω6 and 16:3ω3 than P. australis, (2) the absence of the distinctive distribution pattern of long-chain monocarboxylic and ω-hydroxy acids observed for P. australis, (3) the absence of α, ω-diacids and (4) a lower absolute concentration of ω-hydroxy acids than P. australis.     

Evaluating the impact of predation by fish on the assemblage structure of fishes associated with seagrass (Heterozostera tasmanica) (Martens ex Ascherson) den Hartog, and unvegetated sand habitats

The role of fish predation in structuring assemblages of fish over unvegetated sand and seagrass was examined using enclosure and exclusion cages to manipulate the abundance of predatory fish from November 1998 to January 1999. In our exclusion experiment, piscivorous fish were excluded from patches of unvegetated sand and seagrass to measure how they altered abundances of small fishes, i.e., fish <10 cm in length. Habitats from which piscivorous fish were excluded contained more small fish than those with partial cages, which in turn contained more fish than uncaged areas. These patterns were consistent between unvegetated sand and seagrass areas, although the relative differences between predator treatments varied with habitat. Overall, small fish were more abundant in unvegetated sand than seagrass. Atherinids and syngnathids were the numerically dominant families of small fish and varied in complex ways amongst habitats and cage treatments. The abundance of atherinids varied inconsistently between cage treatments through time. Only during the final two sampling times did the abundance of atherinids vary significantly across cage treatments. Syngnathids were strongly associated with seagrass and were significantly more abundant in caged than uncaged habitats. In our enclosure experiment, five individuals of a single species of transient piscivorous fish, Western Australian salmon (Arripidae: Arripis truttacea Cuvier), were enclosed in cages to provide an estimate of the potential for this species to impact on small fish. The abundance of small fish varied significantly between cage treatments. Small fish were more abundant in enclosure cages and exclusion cages than uncaged areas; however, there was no difference in the abundance of small fish in enclosure cages and partial cages, and no difference between exclusion cages and partial cages. These patterns were consistent amongst habitats. Atherinids and syngnathids were again the numerically dominant families of small fish; atherinids varied more with cage structure while syngnathids did not vary statistically between cages, blocks (locations within which a single replicate of each cage treatment was applied) or habitats. Dietary analysis of caged A. truttacea demonstrated the potential for this species to influence the assemblage structure of small fish through predation - atherinids were consumed more frequently in unvegetated sand than seagrass, and syngnathids were consumed only in seagrass, where they are most abundant. Observations of significant cage or predation effects depended strongly on the time at which sampling was undertaken. In the case of the atherinids, no predation or cage effects were observed during the first two sampling times, but cage effects and predation effects strongly influenced abundances of fish during the third and fourth sampling times, respectively. Our study suggests that transient piscivorous fish may be important in structuring assemblages of small fish in seagrass and unvegetated sand, and seagrass beds may provide a refuge to fishes. But the importance of habitat complexity and predation, in relation to the potentially confounding effects of cage structure, depends strongly on the time at which treatments are sampled, and the periodicity and multiplicity of sampling should be considered in future predation studies.     

Letter from Chile: Re-establishing health care in Chile

Chile''s long term social policy has produced very impressive outcomes in general health indicators, with a national health service established as early as 1952. During the years of the Pinochet dictatorship (1973-89) public health institutions were greatly affected, with sharp diminution in financing which affected investment and salaries. The democratic government initiated in 1990 faced a difficult situation, with underpaid staff and decrepit hospitals. The ministry took immediate action to improve salaries and start an ambitious health sector reform including investment in infrastructure, technology, and modern management. Decentralisation and autonomy, changes in payment for service mechanisms, and a public-private mix are the main objectives of this reform, keeping the public role as predominant in the proposed structure. This process has been affected by union unrest and public opinion dissatisfaction, which tend to present obstacles to progress in this complicated issue.     

Reproductive biology of Stictosiphonia hookeri (Rhodomelaceae,Rhodophyta) from Argentina,Chile, South Africa and Australia in laboratory culture

The red alga Stictosiphonia hookeri is epilithic in shaded habitats of the upper intertidal zone from 30 to 55° S. Thalli of this species from Argentina, Chile, South Africa and Australia, usually without reproductive structures when collected, all developed tetrasporangia in culture. Although good vegetative growth occurred in all nine isolates at 20–25 °C, 12:12 light: dark cycle, 10–30 µmol photons m^–2 s^–1, none reproduced in these conditions except one isolate from Australia. At 15 °C the four South African (34 °S) isolates developed tetrasporangial stichidia, and three completed a Polysiphonia-type life history. Gametophytes were unisexual or bisexual. At 15 °C one isolate from Chile (36 °S) formed tetrasporangia, but sporelings were not viable. At 10 °C isolates from Argentina and Chile (53 °S and 54 °S) formed tetrasporangia; however, only the Chile isolate completed a Polysiphonia-type life history with unisexual gametophytes. The temperature required to induce sporogenesis correlates with the range of water and air temperatures in the natural habitats of each isolate. In irradiances >50 µmol m^–2 s^–1 the thalli became yellow- brown within two weeks because of phycobiliprotein loss, but this did not impair growth or reproduction. The Argentina and Chile isolates were resistant to freezing in seawater for at least two days, showing no cell damage. The protein cuticle of the outer cell wall is repeatedly shed in culture. This may serve to minimize the attachment of epiphytes in the field.     

Comparison of ecosystems in the Mediterranean Basin and Western Australia

A comparison between fire-prone ecosystems in the Mediterranean basin and Western Australia shows convergent adaptations in structure, life forms and flora evolution. Both areas have in common summer drought and winter rainfall. Reproductive biology is mainly correlated with fire ecology; the different length of human impact and history seem to be responsible for floristic divergency in both areas. The ecological significance of pollination by insects, birds and mammals and problems of the seed banks are discussed.     

Morphology and taxonomy of Cyclotella tasmanica spec. nov,a newly described diatom from Tasmanian lakes

A species of Cyclotella with an elliptical valve outline has been found in several Tasmanian lakes and is herein described and named C. tasmanica nov. sp. Morphologically, it is similar to C. stelligera and, to a lesser extent, to C. radiosa. The valve has coarse, clearly alveolate, marginal striae and a central rosette. Unlike other elliptical forms, the central area is always more or less circular. The nearest similar species is C. rhomboideo-elliptica.     

Natural compounds of Palestine flora. Comparison analysis by static headspace and steam distillation GC-MS of semivolatile secondary metabolites from leaves of cultivated Palestinian Majorana syriaca

BACKGROUND: A comparative analysis by using static headspace (HS) and steam distillation (SD) GC-MS of the volatile and the semi-volatile secondary metabolites from leaves of cultivated Majorana syriaca. METHODS: The essential oils endogenous to cultivated thyme were isolated and identified by HS-GC-MS technology and compared to those from SD-GC-MS. RESULTS: The HS-GC-MS results showed that the Palestinian cultivated thyme is rich in monoterpene hydrocarbons and phenolic monoterpenes such as alpha-phellandrene, alpha-pinene, beta-myrcene, m-cymene, p-cymene, gamma-terpinene, thymol and carvacrol. In all the samples gamma-terpinene, p-cymene, thymol and carvacrol were the most abundant compounds. CONCLUSIONS: HS and SD-GC-MS have proved that most of the cultivated thyme samples examined has thymol isomer as the major phenolic constituent.     

Identification of trypanosomes isolated from reduviidae from north Chile

Examination of 54 Triatoma infestans from a village near the European Southern Observatory La Silla in Chile and of 9 Triatoma spinolai from the territory of the observatory showed that 10 T. infestans were infected with trypanosomatids. Mice were infected with in vitro cultures initiated with five different trypanosomatid isolates and treated with the immunosuppressive drug cyclophosphamide to increase the parasitemia of the flagellates. Evidence of the presence of T. cruzi was provided by a comparative biometrical analysis of blood trypomastigotes and the occurrence of intracellular amastigotes. Three methods for further identification were used: examination of kDNA ultrastructure, disc electrophoresis of soluble proteins and the Aaptos papillata II lectin induced agglutination. We obtained the following results for all isolates: (1) presence of a central band of the kDNA; (2) T. cruzi specific double bands of the protein patterns; (3) positive reaction with Aaptos papillata II. No differences between the five isolates from Chile and T. cruzi or T. cruzi-like strains from other countries could be observed. Based on these results an infection of the bugs with T. rangeli and T. conorhini could be excluded.     

A new species of Podospora from soil in Chile

Podospora selenospora sp. nov. isolated from soil in Chile is described and illustrated. It belongs to the group of Podospora species with cylindrical asci, and inequilateral or curved ascospores, with a small, quickly evanescent primary appendage and absence of secondary appendages.     

Ingestion of plant secondary compounds causes diuresis in desert herbivores

Plant secondary compounds are recognized deterrents and toxins to a variety of herbivores. The effect of secondary compounds on water balance of herbivores is virtually unexplored, yet secondary compounds could potentially cause a decrease in an animal's ability to maintain water balance. We investigated the effects of secondary compounds, alpha-pinene and creosote resin, on water balance in three species of herbivorous woodrats (Neotoma stephensi, N. albigula, N. lepida). In separate experiments, we measured the effect of these secondary compounds on voluntary water consumption, urine volume and urine osmolarity. In both experiments, water intake and urine volume increased and urine osmolarity decreased compared to controls. Water balance of specialist or experienced woodrats was less affected than generalists and woodrats with less prior experience with particular secondary compounds. Our results suggest that secondary compounds have diuretic-like effects on herbivores. Woodrats live in arid habitats with limited access to freestanding water; thus an increase in water requirements may have profound consequences on foraging behavior and fitness.     

Characterization of manures from fish cage farming in Chile

This study aims to characterize salmonid manures and to determine their potential use in agricultural soils. Sampling was carried out below salmon and trout cages in farms located in lakes and in the sea in the South of Chile during 2002-2003. Manure was analyzed for macronutrients, micronutrients and heavy metals. Results showed a high variability between samples and differences between sea and lake manure. Dry matter contents were low averaging c. 12-15%. Manures showed low OM contents with values 相似文献   

Intraspecific variation in plant size,secondary plant compounds,herbivory and parasitoid assemblages during secondary succession

During secondary succession on abandoned agricultural fields the diversity and abundance of insect communities often increases, whereas the performance and nutritional quality of early successional plants often declines. As the diversity and abundance of insects on a single plant are determined by characteristics of the environment as well as of the host plant, it is difficult to predict how insects associated with a single plant species will change during succession. We examined how plant characteristics of the early successional plant species ragwort (Jacobaea vulgaris), and the herbivores and parasitoids associated with these plants change during secondary succession. In ten grasslands that differed in time since abandonment (3–26 years), we measured the size and primary and secondary chemistry of individual ragwort plants. For each plant we also recorded the presence of herbivores in flowers, leaves and stems, and reared parasitoids from these plant parts. Ragwort plants were significantly larger but had lower nitrogen concentrations in recently abandoned sites than in older sites. Pyrrolizidine alkaloid (PA) composition varied among plants within sites but also differed significantly among sites. However, there was no relationship between the age of a site and PA composition. Even though plant size decreased with time since abandonment, the abundance of stem-boring insects and parasitoids emerging from stems significantly increased with site age. The proportion of plants with flower and leaf herbivory and the number of parasitoids emerging from flowers and leaves was not related to site age. Parasitoid diversity significantly increased with site age. The results of our study show that ragwort and insect characteristics both change during secondary succession, but that insect herbivore and parasitoid abundances are not directly related to plant size or nutritional quality.     

Dermatophyte infection and colonization in dogs from South Santiago, Chile

Our main aim was to determine the dermatophyte infection and colonization prevalence in canines from South Santiago, Chile. We studied 241 dogs, 121 of them presented cutaneous lesions suggestive of dermatophytosis and the other 120 were free from lesions and were considered clinically healthy. Dermatophytes were isolated from the lesions of 48.8% of animals with cutaneous diseases and from 5% of healthy dogs. Microsporum canis was the principal species isolated with a frequency of 98.3% from dermatophytosis and from all healthy carriers. The direct microscopic test showed a sensibility of 85% with a positive and negative predictive value of 74 and 79%, respectively. The highest prevalence of dermatophytosis were detected in animals up to one year old (p <= 0.05) and in dogs with high level of irritation, scaly skin, itching and alopecia (p < or = 0.05). The lesions were detected more frequently in head-neck and anterior members (p < or = 0.05). This study shows some clinical characteristics and a frequency of dermatophytes in canines that can be interesting for laboratory professionals and veterinarians.     

Herbivore-deterring secondary compounds in heterophyllous woody species of the Mascarene Islands

Heterophylly (juvenile-adult leaf dimorphism) is widespread among native woody species of the Mascarene Islands, but the causes to this phenomenon have so far not been fully explained. The absence of mammals and dominance of now extinct giant tortoises and flightless birds are characteristics of the original Mascarene fauna. The present study investigates the hypothesis that the distinct morphology and colouration of juvenile leaves signalled unpalatability to browsing giant tortoises or birds. Juvenile and adult leaves of 28 heterophyllous woody species endemic to the islands of Mauritius and Rodrigues were screened for possible chemical defences against herbivory. The screening comprised the following classes of secondary compounds: alkaloids, cyanogenic constituents, saponins, simple phenolics, tannins and anthocyanins. The screening showed that there are no consistent significant differences between juvenile and adult leaves regarding any of the studied secondary compound classes, with the exception of the level of anthocyanins, which was significantly higher in juvenile leaves. This difference was also clearly reflected in a generally high degree of red patterning of juvenile leaves. Based on comparisons with floras of other oceanic islands once inhabited by tortoises and birds, and an evaluation of feeding habits of these herbivores, we suggest that the reduced lamina and partly red colouration of juvenile leaves may be an evolutionary response to selective herbivory by birds.     

Presence of polygodial and drimenol in Drimys populations from Chile

Drimys winteri (Winteraceae) is a tree with medicinal properties native to Chile. Its bark contains polygodial and drimenol in unknown quantities, with antimicrobial and antinociceptive activity. The purpose of the present study was to quantify polygodial and drimenol concentrations in leaves of five populations of D. winteri and one of Drimys andina from different regions of Chile, by GC analysis of the hexane extract. The concentration of these compounds was also determined in the bark of one of the D. winteri populations. In dried leaves mean concentrations of 0.99% for polygodial and 0.011% for drimenol could be observed, both differing significantly among the studied populations. It is concluded that polygodial and drimenol are present in the leaves and the bark of D. winteri and in D. andina leaves, this being the first report of the presence of these compounds in the latter species.     

New Cortinarius species from Nothofagus forests in South Chile

Four new Cortinarius species are described from Nothofagus forests in South Chile. Cortinarius aurantiorufus and C. punctatisporus, subgenus Phlegmacium, stirps Inflatipes, are mainly characterized by a viscid to glutinous pileus and a bulbous whitish stipe. They differ in the color of the pileus, and shape, ornamentation, and size of the basidiospores. Futhermore, C. punctatisporus has a translucently striate pileus. Cortinarius rubrivelatus and C. parahumilis belong to subgenus Telamonia, stirps Brunneivelatus and Scabrisporus, respectively. Cortinarius rubrivelatus has a reddish veil, a viscid pileus, and large, ellipsoid to amygdaliform basidiospores. Cortinarius parahumilis has small, subglobose to broadly elliptical, minutely verrucose basidiospores and a viscid pileus.     

Comparison of chemical immobilization methods in wild foxes (Pseudalopex griseus and Pseudalopex culpaeus) in Chile

We immobilized individuals of two species of free-ranging South American foxes, including 28 chilla foxes (Pseudalopex griseus; 13 males and 15 females) and five culpeo foxes (Pseudalopex culpaeus; four males and one female). Animals were trapped and chemically immobilized with ketamine and medetominide (K-M), ketamine and xylazine (K-X), or tiletamine-zolazepam (Z). Heart and respiratory rates, hemoglobin oxygen saturation (SpO2), rectal temperature, and palpebral and anal reflexes were measured at 5-min intervals. Data were analyzed to compare the effect of anesthetic combinations on induction and recovery times, body reflexes, and physiological variables over time. In both species, K-M gave the shortest induction time, followed by K-X and Z. Palpebral and anal reflexes in chilla foxes immobilized with K-M were maintained in more animals than those treated with either K-X or Z. Animals immobilized with Z had higher heart and respiratory rates than those immobilized with either of the other two combinations. Rectal temperature decreased over time for all combinations. Foxes immobilized with K-M maintained a higher SpO2 than those immobilized with either K-X or with Z. All anesthetic combinations were satisfactory in inducing rapid and safe immobilization of the species studied. The anesthetic plane and the effects on physiologic parameters were better in animals immobilized with K-M than with either K-X or Z, and we recommend this anesthetic combination for use in Chilean foxes. Nevertheless, all three drug combinations used were satisfactory in inducing rapid and relatively smooth anesthesia.