Temporal fluctuations of the phytoplankton community of the Baía River, in the upper Paraná River floodplain, Mato Grosso do Sul, Brazil

Subsurface samples were taken monthly (March/1993 through February/1994) in the Baía River, a tributary of the right bank of the Paraná River (22° 43 S and 53° 17 W). We analyzed temporal changes in the phytoplankton community in relation to density, biomass, richness and species diversity, equitability, size structure, and dominance. We related these to regional climate and hydrology, and to the physical and chemical variables of the water column. We determined 119 taxa, wich were numerically dominated by the class Chlorophyceae with 37 taxa. The classes Cyanophyceae and Bacillariophyceae contributed the most abundant biomass and were responsible for the two peaks that were observed. The high water period was generally characterized by lower phytoplankton biomass, higher richness and species diversity, and higher density of nannoplanktonic species such as Monoraphidium tortile in March, and Cryptomonas brasiliensis in January. During low water, however, the highest values of phytoplankton biomass were recorded, with heterocytous cyanophytes dominating during the phase of greater stability of the water column, and filamentous diatoms during periods of mixing turbulence. The fluctuations observed indicate that the hydrosedimentological regime of the Paraná River, together with the climatological factors, constitute the main forcing functions acting on the Baía River phytoplankton.     

Epilithic Diatoms as Indicators of Water Quality in the Gravataí River, Rio Grande do Sul, Brazil

The potential use of epilithic diatoms as indicators of organic pollution was evaluated in Gravataí River, RS, (latitude 29°45′–30°12′ S; longitude 50°27′–51°12′ W). The river suffers agricultural impacts in its upper course and urban and industrial organic pollution in its lower course. Epilithic diatoms were sampled eight times from September 2000 to August 2002, at six sites. Species were identified and densities and relative abundances of populations were determined. Simultaneously, physical, chemical and microbiological variables were measured (water temperature, conductivity, turbidity, pH, dissolved oxygen, biochemical oxygen demand (BOD₅), chemical oxygen demand, ammonium, organic nitrogen, total nitrogen, ortho-phosphate, total phosphate, chloride and faecal coliforms). In order to interpret the environmental and biological variables, discriminant analysis and the TWINSPAN methods (Two-Way Indicator Species Analysis) were applied. The results indicated that the concentrations of ortho-phosphate, ammonium, total organic nitrogen, BOD₅ and faecal coliforms characterized a pollution gradient along the river, where changes in the abundance or species composition were observed. Species were classified into three groups: Group A, including species more tolerant to heavy organic pollution and eutrophication, represented by Luticola goeppertiana, L. mutica, Eolimna subminuscula, Nitzschia palea and Sellaphora pupula; Group B, comprised of tolerant and widely distributed species such as Eunotia bilunaris, Frustulia crassinervia, F. saxonica, Navicula cryptocephala, N. cryptotenella, Nitzschia palea var. tenuirostris, Surirella angusta, Pinnularia microstauron and Ulnaria ulna and Group C, with less pollution tolerant species represented by Eunotia sp. and Gomphonema parvulum.     

Diversity of flies (Diptera: Tephritidae and Lonchaeidae) in organic citrus orchards in the vale do Rio Caí, Rio Grande do Sul, southern Brazil

This study was carried out in the Counties of Montenegro and Pareci Novo located in the region of the Vale do Rio Cai, Rio Grande do Sul, Southern Brazil, aiming to determine the fruit fly species of Tephritidae and Lonchaeidae that occur in organic orchards of sweet orange [Citrus sinensis (L.) Osb.] cultivar Céu, and Murcott tangor (Citrus reticulata Blanco x C. sinensis), during the fruit ripening stages in 2003 and 2004. Eight McPhail traps baited with integral grape juice diluted to 25% were installed in four orchards, two in each citrus species. The traps were checked weekly, when the baits were changed, the flies separated and preserved in 70% ethyl alcohol. Fruits were also sampled from the orchards, placed in containers with damp soil and closed with a mesh. The tephritid flies represented 86.2% of all captured flies in the four orchards during both years. Five Tephritidae species were captured from traps: Anastrepha fraterculus (Wiedemann), Anastrepha grandis (Macquart), Anastrepha pseudoparallela (Loew), Anastrepha dissimilis Stone and Ceratitis capitata (Wiedemann). The captured species of Lonchaeidae were: Neosilba zadolicha McAlpine & Steyskal, Neosilba n.sp.3, Neosilba sp. and Lonchaea sp. Anastrepha fraterculus was found in 99% of the fruit samples, both in 'Céu' orange and 'Murcott' tangor, and Neosilba n.sp.3 were only obtained from 'Murcott' tangor fruits.     

Gene mapping of 5S rDNA sites in eight fish species from the Paraíba do Sul river basin, Brazil

The use of improved cytogenetic techniques such as fluorescent in situ hybridization (FISH) has offered important methodologies for cytotaxonomic and evolutionary studies. In particular, the mapping of 5S rDNA sites has proved to be an excellent marker in the study of different organisms and, more recently, in fish. In the present work, the FISH technique was used to map the 5S rDNA sites in the chromosomes of eight neotropical fish species from the Paraíba do Sul river basin, four of these belonging to the order Characiformes, family Characidae, genus Astyanax (A. scabripinnis, A. parahybae, A. giton and A. intermedius) and four to the order Siluriformes, family Loricariidae (Neoplecostomus microps, Harttia loricariformis, Hypostomus affinis and Upsilodus sp.). Karyotype evolution aspects of the analyzed groups are discussed.     

Planktonic Copepoda of the Upper Paraná River Floodplain lakes (São Paulo and Mato Grosso do Sul,Brazil)

Four series of samples were made during the hydrological cycle of 1992/1993 (October 1992, January, April, and July 1993) to establish the diversity of the planktonic Copepoda community in relation to the trophic state in seven floodplain lakes of the Upper Paraná River system. Sampling was carried out prior to the environmental disturbance caused by the formation of Porto Primavera Reservoir, when 250 km of the Upper Paraná River became standing water in 1998, with the consequent extinction of the original habitats. Nine planktonic species occurred in the Paraná River and floodplain lakes, seven diaptomids and two cyclopids. A trophic state gradient was established, indicating preferences of groups of copepod species for a set of limnological characteristics.     

Diversity and Abundance of the Planktonic Rotifers in Different Environments of the Upper Paraná River Floodplain (Paraná State – Mato Grosso do Sul State,Brazil)

This study proposes that diversity and abundance of rotifers show spatial and temporal variations in the Upper Paraná River floodplain due to heterogeneity of the environment and hydrological level fluctuations of the main river. The structure and dynamics of rotifer assemblages were investigated by samplings carried out during the rainy (February) and dry period (August) of the year 2000, in 36 environments (rivers, channels, backwaters, open and isolated floodplain lakes). The influence of phytoplankton biomass on rotifer diversity and abundance was also investigated. 104 taxa of rotifers were identified. The highest species richness was found in rivers and open floodplain lakes, the highest abundances in the isolated floodplain lakes, and the highest values of species diversity in the channels, especially during the rainy period. β₂-diversity values were higher in the channels, especially during the dry period. Flow differences and food availability were predominant factors influencing the structure and dynamics of the rotifer communities.     

Susceptibility of guava genotypes to natural infestation by Anastrepha spp. (Diptera: Tephritidae) in the municipality of Monte Alegre do Sul, state of São Paulo, Brazil

The infesting species and their infestation indices of fruit flies were determined for eleven guava genotypes (Psidium guajava L.). From March to April 2000, ten mature fruits of each genotype were harvested at weekly intervals from insecticide unsprayed trees located in the municipality of Monte Alegre do Sul, SP, Brazil. Fruits were brought to the laboratory, weighed and placed in individual plastic cups containing sand at the bottom to obtain the tephritid pupae. About 95% of guavas produced fruit fly puparia. Of the 682 Anastrepha females recovered, four species were identified: A. fraterculus (Wied.) (86.5%), A. obliqua (Macquart) (10.8%), A. bistrigata Bezzi (1.8%) and A. sororcula Zucchi (0.9%). Three species of parasitoids Braconidae (Opiinae) were recovered: Doryctobracon areolatus (Szépligeti), Doryctobracon brasiliensis (Szépligeti) and Utetes anastrephae (Viereck). The genotypes differ in level of infestation depend on the collecting time. The genotypes 'L2P4 Vermelha', 'Ruby Suppreme' and 'Webber Suppreme' showed the lowest susceptibility to tephritids in terms of puparia per fruit. The variability of infestation among the guava genotypes and the reasons for increasing fruit fly infestations along the time were discussed.     

Genetic diversity of Tibraca limbativentris Stål (Hemiptera: Pentatomidae) of Santa Catarina and Rio Grande do Sul, Brazil, using RAPD

The work was carried out to test DNA extraction protocols and to characterize populations of Tibraca limbativentris St?l, an important rice insect-pest. Insects were collected in Joinville, Rio do Oeste and Turvo, in Santa Catarina State, and Agudo, Uruguaiana, Pelotas and Palmares do Sul, in Rio Grande do Sul State, and six literature-referenced protocols, besides a new one, were tested. DNA from ten individuals of each population was extracted using the best protocol and RAPD reactions were carried out with ten initiators. The new protocol showed the best results and was used in the PCR reactions, that generated 151 polymorphic bands, allowing to access genetic differences among all the populations; no individuals from one population were clustered with individuals from another. The largest intrapopulacional similarity was found in Uruguaiana (22%), and the smallest in Palmares do Sul (50%), which was also the most divergent population in relation to the others. The Gst was 0.5215, and the Nm was 0.4588; these values reflect the low similarity between the populations. The smallest genic flow was obtained when Palmares do Sul and Pelotas were included in the comparisons, in accordance with the largest divergence of these two populations in relation to the others. There was no significant relation between geographic distance and genetic similarity, which can reflect unknown model of dispersion of T. limbativentris. New studies exploring the species dispersion strategies may help to understand the insect distribution and to unveil the main factors linked to the genetic variability within and between populations.     

Phytoplankton spatial distribution on the Continental Shelf off Rio de Janeiro,from Paraíba do Sul River to Cabo Frio

Given the heterogeneous oceanographic conditions observed in the continental shelf and slope off Rio de Janeiro, the phytoplankton community is expected to adapt to the diverse trophic conditions using distinct strategies. Considering the C-S-R triangle, distinct phytoplankton taxa are expected to occur in Tropical Water (TW), in South Atlantic Central Water (SACW) and in Coastal Water (CW). The study area extends from Paraíba do Sul River mouth to the region of Cabo Frio. Samples were collected on 28 stations, in 2011 austral summer. 209 phytoplankton taxa were observed, mainly dinoflagellates (93), diatoms (71), and coccolitophores (30). TW dominated the surface waters of the continental shelf and slope, and a typical tropical phytoplankton community, composed by stress-tolerant taxa, was observed. The rise in nitrate concentration caused by SACW uplift in the shelf and in the continental slope, at subsurface waters, and in silicate, associated with the Paraíba do Sul riverine plume, led to shifts in the phytoplankton community, increasing the contribution of ruderal taxa. The grouping of phytoplankton assemblages only in traditional groups would result in loss of information about the factors that determine community dynamics since the different species in each of these groups frequently share specific traits.     

Malaria vectors in the municipality of Serra do Navio, State of Amapá, Amazon Region, Brazil

We conducted a survey to determine the vectors of malaria in six localities of Serra do Navio municipality, State of Amapá, from 1990 to 1991. Malaria infection rates of 29.3%, 6.2% and 20.4% were detected by human blood smears in Col?nia Agua Branca, Porto Terezinha and Arrependido, respectively. There was no malaria infection detected in Serra do Navio. Fifteen species were identified among 3,053 anopheline mosquitoes collected by human bait and 64.4% were identified as Anopheles albitarsis s.l., 16.7% An. braziliensis, 9.5% An. nuneztovari and 5.8% An. triannulatus. An. darlingi, the main vector of malaria in the Amazon region of Brazil, was scare. Using enzyme-linked immunosorbent assay (ELISA), a total positive rate of 0.8% (23/2876) was found for six species: fifteen An. albitarsis s.l., four An. nuneztovari, and one of each: An. braziliensis, An. triannulatus, An. oswaldoi and An. rangeli. Nine of 23 positive mosquitoes were infected with Plasmodium malariae, eight with P. vivax VK210, three with P. vivax VK247 and three with P. falciparum. Since An. albitarsis s.l. was collected feeding on humans, was present in the highest density and was positive by ELISA for malaria sporozoites, it probably plays an important role in malaria transmission in this area.     

When do sperm of the sea urchin,Pseudocentrotus depressus,undergo the acrosome reaction at fertilization?

Jelly coats of the sea urchin, Pseudocentrotus depressus, were stripped off the eggs, and the eggs were “inseminated.” After penetration through the isolated jelly hull, sperm swarmed in the cavity previously occupied by the egg. Electron microscopic examination could not detect any sperm with reacted acrosome. Observation was also made of the sperm penetrating through the intact jelly coat-egg complex. Although a number of sperm were examined in ultrathin sections, only those attached to the vitelline layer had undergone the acrosome reaction; those sperm embedded in jelly but not attached to the vitelline layer had not undergone the acrosome reaction. The sequence of events in fertilization of this species and of other echinoids is discussed.     

Larval fish assemblage in the Baía River (Mato Grosso do Sul State,Brazil): temporal and spatial patterns

Synopsis We sampled the Baía River (Mato Grosso do Sul State, Brazil) monthly, to survey taxonomic composition and temporal and spatial distribution of fish larvae. The ichthyoplankton was mainly composed by larvae of small and medium sized sedentary species and it was numerically dominated by six taxa: Plagioscion squamosissimus, Hypophthalmus edentatus, Hoplias aff. malabaricus, Bryconamericus stramineus, Serrasalmus spp. and Catathyridium jenynsii. These taxa present distinct temporal and spatial occurrence patterns: H. edentatus, B. stramineus and C. jenynsii are abundant between September and March in lentic areas; H. aff. malabaricus and Serrasalmus spp. were caught between October and February in lotic areas; whereas P. squamosissimus occurs in all sampled areas, with peak of capture in January. Hypophthalmus edentatus, H. aff. malabaricus, Serrasalmus spp. and B. stramineus were the taxa that most contributed to structure the assemblages temporally and spatially, and their abundances were influenced by the interaction of several environmental variables.     

How do plants regulate the function, community structure, and diversity of mycorrhizal fungi?

In many semi-natural and natural ecosystems, mycorrhizal fungi are the most abundant and functionally important group of soil micro-organisms. They are almost wholly dependent on their host plants to supply them with photosynthate in return for which they enable the plant to access greater quantities of nutrients. Thus, there is considerable potential for plant communities to regulate the structure and function of mycorrhizal communities. This paper reviews some of the key recent developments that have enabled the influence of plant species richness, composition, and age on mycorrhizal communities in boreal forests and temperate grassland to be determined. It discusses the emerging evidence that, in some situations, plant species richness is related to mycorrhizal species richness, in contrast to previous thinking. The paper also includes some preliminary data on the effect of host stand age on root-associated basidiomycete communities. It concludes by highlighting some of the new methodological advances that promise to unravel the linkages between mycorrhizal diversity and their function in situ.     

Improving the role of immune checkpoint inhibitors in the management of advanced urothelial carcinoma,where do we stand?

Immune checkpoint inhibitors (ICIs) have significantly improved the outcome of patients with metastatic urothelial cancer (mUC). If these agents were first used in monotherapy after failure of platinum-based chemotherapy, new strategies have been evaluated in the last years, including association of ICIs, ICI plus chemotherapy association or maintenance therapy. This maintenance concept allows a better management of mUC, which is particularly interesting in cisplatin-ineligible patients.This paper aims to review the current knowledge of ICIs in urothelial carcinoma as well as the new indications of these agents in mUC.     

How do you feel? Interoception: the sense of the physiological condition of the body

As humans, we perceive feelings from our bodies that relate our state of well-being, our energy and stress levels, our mood and disposition. How do we have these feelings? What neural processes do they represent? Recent functional anatomical work has detailed an afferent neural system in primates and in humans that represents all aspects of the physiological condition of the physical body. This system constitutes a representation of 'the material me', and might provide a foundation for subjective feelings, emotion and self-awareness.     

What do Biologists Make of the Species Problem?

The concept of species is one of the core concepts in biology and one of the cornerstones of evolutionary biology, yet it is rife with conceptual problems. Philosophers of biology have been discussing the concept of species for decades, and in doing so they sometimes appeal to the views of biologists. However, their statements as to what biologists think are seldom supported by empirical data. In order to investigate what biologists actually think about the key issues related to the problem of species, we have conducted a survey on the sample of 193 biologists from the population of biologists from over 150 biology departments at universities in the US and the EU. This article presents and discusses the results of the survey. Some results confirm and others falsify the reiterated statements of philosophers of biology as to what biologists think, but all results we obtained should be informative and relevant for future discussions of the problem of species.     

Four new records of the phlebotominic fauna of the Genus Lutzomyia França (Diptera: Psychodidae, Phlebotominae) of the rural district of Brejo do Mutambal, Varzelândia, State of Minas Gerais, Brazil

During April and May 2006, experiments were carried out in Brejo do Mutambal, Varzelandia Town, Minas Gerais State, to evaluate the attractiveness of phlebotomine sandflies to CDC light traps, baited with kairomones. Of the 19 species of Lutzomyia already registered for the region, L. lutziana (Costa Lima), L. longipennis (Barreto), L. goiana (Martins, Falc?o & Silva) and L. brasiliensis (Costa Lima) were recorded for the first time, thus increasing the diversity of phlebotomine sandflies fauna in this area to 23 species. The new registered species and distribution are shown and discussed herein.     

What do the indices of reproductive skew measure?

Several indices of reproductive skew that quantify the degree of unequal partitioning of reproductive output among individuals have been proposed without consensus on their merits and defects. We believe that the major reason for the disagreement is the lack of discussion on what the population parameter of skew (population skew or true skew) should measure. In our view, the skew index should be an unbiased estimate of a population skew, and the estimated skew needs to satisfy the following two conditions. First, if the group size is equal and the distribution of potential of reproductive output (pi), which is scaled by the proportion of the individual's to the total group reproductive output, is also fixed, skew remains constant even when the total number of offspring in the group changes. Second, if the group size is different, skew should have intuitive biological meaning. Our analyses revealed that, among various indices so far proposed, only the skews estimated by Kokko and Lindstr?m's lambda and Morisita's I(delta) satisfy the first condition. However, the two indices estimate different population parameters, thus implying different biological meanings. Morisita's I(delta) is a linear function of CV(2) (squared coefficient of variation) of pi, and lambda is a positive function of [Formula: see text] when offspring number follows a multinomial distribution. In the special cases where a group consists of discrete classes of breeders and nonbreeders, lambda behaves roughly inversely parallel to the absolute number of breeders, while I(delta) moves almost parallel to the proportion of nonbreeders. Furthermore, lambda is sensitive to the total proportion of reproductive output possessed by the dominants but is relatively less sensitive to the number of subordinates. We discussed the possible situations where either of the two indices will be useful.     

How do the suprachiasmatic nuclei of the hypothalamus integrate photoperiodic information?

The suprachiasmatic nucleus of the hypothalamus (SCN) plays an essential role in the generation and maintenance of circadian rhythms in mammals. The SCN activity is also dependent upon the photoperiod. The duration of the SCN sensitive phase to light, in term of Fos induction, is variable and tied to the length of the night. The question is how and by which pathways can photoperiod influence SCN? It is possible following the theoretical model of evening and morning component of the clock that the SCN build itself the photoperiodic signal. That the SCN integrate the photoperiodic information through indirect neural or neuroendocrine pathways is also to consider. Data in favor of these different interpretations are presented.