An approach based on the total‐species accumulation curve and higher taxon richness to estimate realistic upper limits in regional species richness

Most of accumulation curves tend to underestimate species richness, as they do not consider spatial heterogeneity in species distribution, or are structured to provide lower bound estimates and limited extrapolations. The total‐species (T–S) curve allows extrapolations over large areas while taking into account spatial heterogeneity, making this estimator more prone to attempt upper bound estimates of regional species richness. However, the T–S curve may overestimate species richness due to (1) the mismatch among the spatial units used in the accumulation model and the actual units of variation in β‐diversity across the region, (2) small‐scale patchiness, and/or (3) patterns of rarity of species. We propose a new framework allowing the T–S curve to limit overestimation and give an application to a large dataset of marine mollusks spanning over 11 km² of subtidal bottom (W Mediterranean). As accumulation patterns are closely related across the taxonomic hierarchy up to family level, improvements of the T–S curve leading to more realistic estimates of family richness, that is, not exceeding the maximum number of known families potentially present in the area, can be considered as conducive to more realistic estimates of species richness. Results on real data showed that improvements of the T–S curve to accounts for true variations in β‐diversity within the sampled areas, small‐scale patchiness, and rarity of families led to the most plausible richness when all aspects were considered in the model. Data on simulated communities indicated that in the presence of high heterogeneity, and when the proportion of rare species was not excessive (>2/3), the procedure led to almost unbiased estimates. Our findings highlighted the central role of variations in β‐diversity within the region when attempting to estimate species richness, providing a general framework exploiting the properties of the T–S curve and known family richness to estimate plausible upper bounds in γ‐diversity.     

<Emphasis Type="Italic">Isospora lopesi</Emphasis> n. sp. (Apicomplexa: Eimeriidae) from the eastern white-throated spadebill <Emphasis Type="Italic">Platyrinchus mystaceus</Emphasis> Vieillot (Passeriformes: Tyranni: Tyrannidae) in South America

A species of Isospora Schneider, 1881 (Protozoa: Apicomplexa: Eimeriidae) considered as new to science is described and characterised molecularly from the eastern white-throated spadebill Platyrinchus mystaceus Vieillot in the Parque Nacional do Itatiaia, southeastern Brazil. Isospora lopesi n. sp. has oöcysts that are subspheroidal to ovoidal, 18–24 × 18–22 (20.6 × 19.7) µm, with smooth, bilayered wall, c.1.5 μm thick. Micropyle and oöcyst residuum are absent, but one polar granule is present. Sporocysts are ellipsoidal, 12–16 × 8–11 (14.4 × 8.6) µm. The Stieda body is flattened to half-moon-shaped and sub-Stieda body is rounded. Sporocyst residuum is present, consisting of numerous spherules of different sizes. Sporozoites are vermiform with anterior and posterior refractile bodies and nucleus. Molecular analysis was conducted at the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene. This new isolate exhibited similarity greater than 98% with Isospora spp. isolates from spectacled warblers Sylvia conspicillata Temminck, 1820. This is the fourth isosporoid coccidian described from New World tyrannid birds, but is the first to have a complementary molecular characterisation.     

Carry‐over effects provide linkages across the annual cycle of a Neotropical migratory bird,the Louisiana Waterthrush Parkesia motacilla

Population limitation models of migratory birds have sought to include impacts from events across the full annual cycle. Previous work has shown that events occurring in winter result in some individuals transitioning to the breeding grounds earlier or in better physical condition than others, thereby affecting reproductive success (carry‐over effects). However, evidence for carry‐over effects from breeding to wintering grounds has been shown less often. We used feather corticosterone (CORT_f) levels of the migratory Louisiana Waterthrush Parkesia motacilla as a measure of the physiological state of birds at the time of moult on the breeding territory to investigate whether carry‐over effects provide linkages across the annual cycle of this stream‐obligate bird. We show that birds arriving on wintering grounds with lower CORT_f scores, indicating reduced energetic challenges or stressors at the time of moult, occupied higher quality territories, and that these birds then achieved a better body condition during the overwinter period. Body condition, in turn, was important in determining whether adult birds returned the following winter, with birds in better condition returning at higher rates. Together these data suggest a carry‐over effect from the breeding grounds to the wintering grounds that is further extended with respect to annual return rates. Very few other studies have linked conditions during the previous breeding season with latent effects during the subsequent overwintering period or with annual survival. This study shows that the effects of variation in energetic challenges or stressors can potentially carry over from the natal stream and accumulate over more than one life‐history period before being manifested in reduced survival. This is of particular relevance to models of population limitation in migratory birds.     

Diversity patterns and chronobiology of hawkmoths (Lepidoptera,Sphingidae) in the Brazilian Amazon rainforest

As biodiversity loss rapidly increases through habitat degradation in the Amazon rainforest, the need to characterize and understand the species diversity becomes even more important. In this study we used empirical and published datasets to assess the diversity patterns and produce the first overview of the sphingid fauna in the Brazilian Amazon. We compared the diversity patterns in distinct areas in the biome by analyzing hawkmoth assemblages considering both species composition and abundance, and asked whether these communities are structured according to environmental factors. Additionally, we provide information of diel activity pattern of sphingids and evaluated the importance of time in sampling effort. We found that the Brazilian Amazon may harbor more than 80 % of the hawkmoth species that occur in Brazil and more than half of the species recorded in South America. Species composition and assemblage structure is determined by the quality of the habitat (disturbed or undisturbed vegetation), temperature and relative humidity. Finally, we show that the temporal activity of sphingids presents distinct patterns at different taxonomic levels, highlighting the importance of full night collections to better characterize the fauna. Our results show that habitat alteration can be an important factor affecting sphingid assemblages, illustrating the importance of Protected Areas in species maintenance.     

Induction by Hypoxia of Heterologous-Protein Production with the KlPDC1 Promoter in Yeasts

The control of promoter activity by oxygen availability appears to be an intriguing system for heterologous protein production. In fact, during cell growth in a bioreactor, an oxygen shortage is easily obtained simply by interrupting the air supply. The purpose of our work was to explore the possible use of hypoxic induction of the KlPDC1 promoter to direct heterologous gene expression in yeast. In the present study, an expression system based on the KlPDC1 promoter was developed and characterized. Several heterologous proteins, differing in size, origin, localization, and posttranslational modification, were successfully expressed in Kluyveromyces lactis under the control of the wild type or a modified promoter sequence, with a production ratio between 4 and more than 100. Yields were further optimized by a more accurate control of hypoxic physiological conditions. Production of as high as 180 mg/liter of human interleukin-1β was obtained, representing the highest value obtained with yeasts in a lab-scale bioreactor to date. Moreover, the transferability of our system to related yeasts was assessed. The lacZ gene from Escherichia coli was cloned downstream of the KlPDC1 promoter in order to get β-galactosidase activity in response to induction of the promoter. A centromeric vector harboring this expression cassette was introduced in Saccharomyces cerevisiae and in Zygosaccharomyces bailii, and effects of hypoxic induction were measured and compared to those already observed in K. lactis cells. Interestingly, we found that the induction still worked in Z. bailii; thus, this promotor constitutes a possible inducible system for this new nonconventional host.     

Isolation, Nucleotide Sequence, and Physiological Relevance of the Gene Encoding Triose Phosphate Isomerase from Kluyveromyces lactis

Lack of triose phosphate isomerase activity (TIM) is of special interest because this enzyme works at an important branch point of glycolytic flux. In this paper, we report the cloning and sequencing of the Kluyveromyces lactis gene encoding TIM. Unlike Saccharomyces cerevisiae ΔTPI1 mutants, the K. lactis mutant strain was found to be able to grow on glucose. Preliminary bioconversion experiments indicated that, like the S. cerevisiae TIM-deficient strain, the K. lactis TIM-deficient strain is able to produce glycerol with high yield.     

Time-dependent attachment mechanism of bacterial pathogen during ice-ice infection in Kappaphycus alvarezii (Gigartinales, Rhodophyta)

The mechanism of infection by Vibrio sp. P11 promoting the ice-ice disease in Kappaphycus alvarezii was investigated in vitro. Its intensity of infection differs from that of another ice-ice promoter (Cytophaga sp. P25) by promoting the disease much faster. However, when secondary infection by other bacteria starts, its ability to compete with these bacteria gradually diminishes, whereas, infection by P25, although not displaying such drastic effects as P11, shows consistent competitive ability against other bacteria. Time-series infection experiments with application of polyclonal antibodies to specifically detect Vibrio sp. P11 revealed that this bacterium has a high affinity for the seaweed especially when the latter is stressed. It promotes the disease after a rapid increase in cell density of up to 10⁷ g⁻¹ (wet wt.) in the first 24 h. This bacterial cell build-up may take only 1–2 h on stressed thalli, but takes about 24 h on non-stressed thalli. Build-up is not sustainable in non-stressed thalli as high density is usually followed by a sudden decline in cell number believed to result from an algal defence against potential pathogens. Inoculation of the bacterium on thalli incubated in continuous culture system extends the time of bacterial attachment due to laminar flow and, possibly, competition by existing bacteria on the seaweed surface and in ambient seawater medium. Motility-driven cell attachment by this bacterium is suggested as an important factor for infection. This revised version was published online in June 2006 with corrections to the Cover Date.     

Glyphosate affects chlorophyll,photosynthesis and water use of four Intacta RR2 soybean cultivars

The planting of RR2 Intacta soybeans by farmers has been expanding strongly. However, some visual injuries have been noted after glyphosate application. The aim of this study was to evaluate the influence of glyphosate application on chlorophyll, photosynthesis and water use of four Intacta RR2 soybean cultivars. The experiment was conducted in a greenhouse, in a randomized block design with a 3 × 4 factorial scheme, consisting of three glyphosate rates and four soybean cultivars. The glyphosate formula used was isopropylamine salt + potassium salt. The parameters analyzed were phytotoxicity at 7, 14, 21 and 28 days after application, and total chlorophyll index at 0, 3, 7, 14, 21, 28, 35, 42 and 49 days after application. Furthermore, 40 days after application, the net CO2 assimilation rate (A), transpiration rate (E), stomatal conductance (G), and internal CO₂ concentration (Ci) were evaluated as well. The water-use efficiency (WUE) and carboxylation efficiency were calculated. The data were submitted to analysis of variance and compared by the Tukey’s test (p ≤ 0.05), followed by regression analysis. The phytotoxicity influence could be seen until 21 days after application, in which Monsoy 6210 IPRO cultivar was the most injured. The increasing doses promoted a reduction of the chlorophyll level up to 35 days after application in Monsoy 6410 IPRO. The cultivars tested here showed similar chlorophyll index values. On the 3rd, 7th and 14th DAA (Fig. 5a–c), there was a significant linear decline in the chlorophyll index with rising glyphosate dose for all four cultivars. The chlorophyll index cultivars were not influenced by the doses on the 42nd and 49th DAA. There was no difference in water use and carboxylation efficiency. The parameters A, E and A/Ci showed a positive correlation as the doses increased, while Ci declined, in both cultivars. The application of glyphosate on these soybean cultivars causes different injuries according to the sensitivity. In general, RR2 soybeans have the ability to recover from visual intoxication injuries and reestablish the normal chlorophyll production and photosynthetic parameters after glyphosate application.