Microsatellite markers for the common bean Phaseolus vulgaris

Efforts to develop molecular tools for genetic analysis and breeding of common bean in the tropics are still limited. The number of microsatellite markers available for the crop is small compared to other crops of similar social and economic importance. As part of a project to broaden the use of molecular tools in bean breeding, a genomic library enriched for AG/TC repeat sequences was constructed for Phaseolus vulgaris. Twenty microsatellite markers were initially developed and 10 were characterized using a panel of 85 representative accessions of the bean gene bank. The number of alleles per marker ranged from three to 10. The polymorphism information content (PIC) varied from 0.23 to 0.80. The results indicate that the new markers can be readily used in genetically analysis of common bean.     

Water deprivation tolerance and humidity response in a larval dragonfly: a possible adaptation for survival in drying ponds

Abstract.  Water deprivation tolerance is investigated in the last larval stadium of Libellula depressa under various conditions of relative humidity (60–100% relative humidity; RH). Most of the larvae maintained at 100% RH emerge and, at lower RH levels show some resistance to dehydration because they die after a mean period ranging from 1.4 days at 60% RH up to 6.7 days at 90% RH. In dual-choice chambers with humidity gradients from 63–74% RH and from 68–84% RH, larvae spend most of the time in the moist side of the chamber. In a Y-tube olfactometer, the larvae reveal a positive hygrotaxis to two airstreams carrying different amounts of water vapour (98% vs. 50%) and spend most of their time in the 'humid' arm. The ecological significance of desiccation tolerance and hygropositive response in the last larval stadium of L. depressa is discussed in relation to the presence of hygroreceptors in dragonfly larvae.     

Deficit schizophrenia: an update

The criteria for deficit schizophrenia were designed to define a group of patients with enduring, primary (or idiopathic) negative symptoms. In 2001, a review of the literature suggested that deficit schizophrenia constitutes a disease separate from nondeficit forms of schizophrenia. Here we provide a review of new studies, not included in that paper, in which patients with deficit schizophrenia and those with nondeficit schizophrenia were compared on dimensions typically used to distinguish diseases: signs and symptoms, course of illness, pathophysiological correlates, risk and etiological factors, and treatment response. Replicated findings and new evidence of double dissociation supporting the separate disease hypothesis are highlighted. Weaknesses in research and treatment options for these patients are also emphasized.     

Analysis of the heterochromatin of <Emphasis Type="Italic">Cebus</Emphasis> (Primates,Platyrrhini) by micro-FISH and banding pattern comparisons

The karyotype of the neotropical primate genus Cebus (Platyrrhini: Cebidae), considered the most ancestral one, shows the greatest amount of heterochromatin described among Platyrrhini genera. Banding techniques and restriction enzyme digestion have previously revealed great variability of quantity and composition of heterochromatin in this genus. In this context, we use fluorescence in situ hybridization (FISH) to analyse this genomic region and discuss its possible role in the diversification of Cebus. We used a heterochromatin probe for chromosome 11 of Cebus libidinosus (11qHe+ CLI probe), obtained by chromosome microdissection. Twenty-six specimens belonging to the families Atelidae, Cebidae, Callitrichidae and Pithecidae (Platyrrhini) were studied. Fourteen out of 26 specimens were Cebus (Cebidae) individuals of C. libidinosus, C. xanthosternos, C. apella, C. nigritus, C. albifrons, C. kaapori and C. olivaceus. In Cebus specimens, we found 6 to 22 positive signals located in interstitial and telomeric positions along the different species. No hybridization signal was observed among the remaining Ceboidea species, thus reinforcing the idea of a Cebus-specific heterochromatin composed of a complex system of repetitive sequences.     

Isolation of microsatellite loci in green abalone (Haliotis fulgens) and cross‐species amplification in two other North American red (Haliotis rufescens) and pink (Haliotis corrugata) abalones

Microsatellite loci were isolated in Haliotis fulgens using a (CT)_n enriched‐genomic library. From 33 sequenced clones, 21 microsatellites regions were identified, 15 with the expected (CT)_n. Eight microsatellite loci were amplified, six of which were polymorphic with a range of three to 20 alleles, and five cross‐amplified in two other species (Haliotis rufescens and Haliotis corrugata). These microsatellites will be useful as population genetic markers in the three species.     

Environmental variability drives phytoplankton assemblage persistence in a subtropical reservoir

Temporal changes of assemblages may result from environmental variability and reflect seasonal dynamics of their ecosystem. In the subtropics, the hydrological regime is usually characterized by well‐defined wet and dry seasons, regulating discharge and influencing a series of environmental variables that affect phytoplankton persistence. Therefore, we may expect that dry seasons are environmentally more stable than wet seasons. We analysed interannual phytoplankton assemblage variability (or, inversely, persistence) in a subtropical reservoir sampled every austral summer and winter during 5 years. We tested (i) if phytoplankton assemblage structure differed between the dry (summer) and wet (winter) seasons; (ii) if assemblage persistence differed between the seasons; (iii) if assemblage persistence was related to environmental stability; and (iv) if assemblage dissimilarity increased over time. Phytoplankton assemblages differed between the summer and winter seasons. Winter indicator species were mostly Bacillariophyceae or Cryptophyceae, whereas Cyanophyceae and Chlorophyceae taxa were more frequent and abundant in summer. Assemblages in the dry season were more persistent among years than those occurring during rainy periods. Similarly, environmental variability tended to be lower among dry than among rainy seasons. The relation between the phytoplankton temporal cycle and the temporal patterns of environmental variability supports our prediction that high environmental stability results in more persistent assemblages. Assemblage dissimilarity increased as sampling years were farther apart, for both seasons. Additionally, assemblages in the rainy periods showed a more pronounced increase in dissimilarity, as their changes among years were less predictable. We found a clear temporal pattern and an increased dissimilarity over time in the phytoplankton assemblage structure. Unravelling these temporal patterns may improve our understanding of phytoplankton temporal dynamics, and may have implications for management and monitoring programs. High dissimilarity of assemblages among years, particularly among rainy periods, can obscure human impacts, and monitoring programs should take this into account.     

Bat-pollinated Flower Assemblages and Bat Visitors at Two Atlantic Forest Sites in Brazil

A comparison between bat-pollinated plant assemblages at twosites in different altitudinal ranges covered by the Atlanticrainforest in southeastern Brazil is presented. The lowlands(5–90 m) harbour ten plant species in seven families,pollinated mostly by three glossophagine bat species. The highlands(1540–1600 m) harbour seven plant species in five families,pollinated by a single species of glossophagine. Bromeliadsaccount for about 30% of the bat-pollinated species at eachassemblage. Tube and brush shapes prevail in the flowers atboth sites. Corolla lengths averaged 26.8 and 37.2 mm, sugarconcentrations in nectar averaged 15.0 and 18.1%, and nectarvolumes averaged 150.8 and 167.0 µl in the lowland andhighland assemblages, respectively. The flowers are pollinatedmostly by glossophagine bats during hovering visits, and theplants are visited in the trap-line foraging pattern. The plantsbloom annually and both assemblages show a staggered continualflowering pattern. Flowering seasonality was found at both sites,with flowering clustering in the drier season at the lowlandsite and in the wetter season at the highland site. The ratiobetween bat-pollinated and hummingbird-pollinated species is0.24 at the lowland site and 0.23 at the highland one. Thesesimilar values indicate that additional studies on bat- andbird-pollinated assemblages are merited at other Atlantic rainforestsites.Copyright 1999 Annals of Botany Company Abutilon,bat-pollination,Dyssochroma, Eriotheca, Hillia, Lafoensia, Marcgravia,rainforest,Siphocampylus,southeastern Brazil,Tetrastylis, Vriesea.