Length-weight relationships of ornamental fish species from Amanã Lake,Amanã Reserve,Amazonas, Brazil

Length-weight relationships (LWRs) were estimated for 16 ornamental fish species from Amanã Lake and nine tributary streams, in Central Brazilian Amazonia. Sampling was carried out bimonthly for a year (2007–2008), using two sets of four gillnets (20 m × 2 m, 2,5; 3,5; 04; 4,5 cm stretch mesh size); trawls were performed with seine nets (35 m × 6 m, 3 mm stretch mesh size); native fish-traps (fyke-net like fish-traps woven from local lianas), and dip nets (0.5 m × 0.5 m stretch mesh size). Measurements were done for standard length (SL – 0.1 cm precision) and total weight (Wt – 0.01 g precision). This study provides information on the length–weight relationships for all sampled species and, in addition, provides new maximum standard lengths for six species.     

Invasive potential of golden and zebra mussels in present and future climatic scenarios in the new world

Hydrobiologia - Biological invasions and climate change are important drivers of biodiversity loss. In freshwater ecosystems, golden and zebra mussels are two highly aggressive invasive species...     

The Crown Pearl: a draft genome assembly of the European freshwater pearl mussel Margaritifera margaritifera (Linnaeus, 1758)

Since historical times, the inherent human fascination with pearls turned the freshwater pearl mussel Margaritifera margaritifera (Linnaeus, 1758) into a highly valuable cultural and economic resource. Although pearl harvesting in M. margaritifera is nowadays residual, other human threats have aggravated the species conservation status, especially in Europe. This mussel presents a myriad of rare biological features, e.g. high longevity coupled with low senescence and Doubly Uniparental Inheritance of mitochondrial DNA, for which the underlying molecular mechanisms are poorly known. Here, the first draft genome assembly of M. margaritifera was produced using a combination of Illumina Paired-end and Mate-pair approaches. The genome assembly was 2.4 Gb long, possessing 105,185 scaffolds and a scaffold N50 length of 288,726 bp. The ab initio gene prediction allowed the identification of 35,119 protein-coding genes. This genome represents an essential resource for studying this species’ unique biological and evolutionary features and ultimately will help to develop new tools to promote its conservation.     

Micropropagation of Zeyheria montana Mart. (Bignoniaceae), an endangered endemic medicinal species from the Brazilian cerrado biome

Zeyheria montana Mart. has become endangered, primarily because of deforestation of its habitat, its use as a medicinal plant extract, and the strong endemism of the species. In this study, an efficient protocol was established for the micropropagation and conservation of Z. montana germplasm using isolated mature zygotic embryos as explants. Embryos germinated in vitro 4 d after isolation and inoculation on modified Murashige and Skoog (MS) medium containing 2.0 mg/l gibberellic acid (GA₃). The addition of GA₃ also improved the germination index and accelerated the process of germination. Nodal segments from seedlings were placed on modified ¼-strength MS medium containing 0.1 mg/l 6-benzyladenine and 0.5 mg/l GA₃. Nodal segments produced 7.3 shoots per explant within 60 d. Following transfer of shoots to a medium containing 1.5 mg/l indole-3-butyric acid, roots formed. All plantlets obtained were successfully acclimatized under greenhouse conditions, and approximately 68.5 acclimatized plants could be obtained per seed each year. This protocol provides a method to preserve this rare and endangered medicinal plant.     

Morphological and immunohistochemical study of the midgut and fat body of Spodoptera frugiperda (J.E. Smith) (Lepidoptera: noctuidae) treated with essential oils of the genus Piper

ABSTRACT

Essential oils are a promising alternative to insecticides. We investigated the LD₅₀ of oils extracted from Piper corcovadensis, P. marginatum, and P. arboreum after 48 h topical contact with Spodoptera frugiperda larvae using morphometry, histochemistry and immunohistochemistry of the midgut and fat body. Chromatography revealed that E-caryophyllene was the principal compound common to the Piper species. The essential oils of P. corcovadensis, P. marginatum and P. arboreum caused deleterious changes in the midgut of S. frugiperda larvae. P. corcovadensis oil produced the lowest LD₅₀ and significant histopathological alterations including elongation of the columnar cells, formation of cytoplasmic protrusions, reduction in carbohydrate, increased apoptotic index and decreased cell proliferation. P. arboreum oil caused histopathological alterations similar to P. corcovadensis, but caused the highest rate of cell proliferation and increased regenerative cells, which indicated rapid regeneration of the epithelium. Our findings demonstrated the insecticidal potential of P. corcovadensis for control of S. frugiperda owing to the significant damage it inflicted on S. frugiperda midgut.     

Phloroglucinol in plant tissue culture

In plant tissue culture research, there is a constant need to search for novel substances that could result in better or more efficient growth in vitro. A relatively unknown compound, phloroglucinol (1,3,5-trihydroxybenzene), which is a degradation product of phloridzin, has growth-promoting properties. Phloroglucinol increases shoot formation and somatic embryogenesis in several horticultural and grain crops. When added to rooting media together with auxin, phloroglucinol further stimulates rooting, most likely because phloroglucinol and its homologues act as auxin synergists or auxin protectors. Of particular interest is the ability of phloroglucinol—a precursor in the lignin biosynthesis pathway—to effectively control hyperhydricity through the process of lignification, thus maximizing the multiplication rate of woody species and other species that are difficult to propagate. Phloroglucinol has also been used to improve the recovery of cryopreserved Dendrobium protocorms, increasing the potential of cryopreservation for application in ornamental biotechnology. Phloroglucinol demonstrates both cytokinin-like and auxin-like activity, much like thidiazuron, and thus has considerable potential for application in a wide range of plant tissue culture studies.     

Genetic divergence between Melipona quadrifasciata Lepeletier (Hymenoptera,Apidae) populations

Melipona quadrifasciata is a stingless bee widely found throughout the Brazilian territory, with two recognized subspecies, M. quadrifasciata anthidioides, that exhibits interrupted metasomal stripes, and M. quadrifasciata quadrifasciata, with continuous metasomal stripes. This study aimed to estimate the genetic variability of these subspecies. For this purpose, 127 colonies from 15 Brazilian localities were analyzed, using nine species-specific microsatellite primers. At these loci, the number of alleles ranged from three to 15 (mean: 7.2), and the observed heterozygosity (H_o) ranged from 0.03–0.21, while the expected heterozygosity (H_e) ranged from 0.23–0.47. The genetic distances among populations ranged from 0.03–0.45. The F_ST multilocus value (0.23) indicated that the populations sampled were structured, and the clustering analysis showed the formation of two subgroups and two more distant populations. The first group contained the subspecies M. quadrifasciata quadrifasciata, and the other, the subspecies M. quadrifasciata anthidioides and the two M. quadrifasciata populations with continuous metasomal stripes from northern Minas Gerais. These results confirmed that the yellow metasomal stripes alone are not a good means for correctly identifying the different subspecies of M. quadrifasciata.     

Phylogenetic Analysis Reveals a High Prevalence of Sporothrix brasiliensis in Feline Sporotrichosis Outbreaks

Sporothrix schenckii, previously assumed to be the sole agent of human and animal sporotrichosis, is in fact a species complex. Recently recognized taxa include S. brasiliensis, S. globosa, S. mexicana, and S. luriei, in addition to S. schenckii sensu stricto. Over the last decades, large epidemics of sporotrichosis occurred in Brazil due to zoonotic transmission, and cats were pointed out as key susceptible hosts. In order to understand the eco-epidemiology of feline sporotrichosis and its role in human sporotrichosis a survey was conducted among symptomatic cats. Prevalence and phylogenetic relationships among feline Sporothrix species were investigated by reconstructing their phylogenetic origin using the calmodulin (CAL) and the translation elongation factor-1 alpha (EF1α) loci in strains originated from Rio de Janeiro (RJ, n = 15), Rio Grande do Sul (RS, n = 10), Paraná (PR, n = 4), São Paulo (SP, n = 3) and Minas Gerais (MG, n = 1). Our results showed that S. brasiliensis is highly prevalent among cats (96.9%) with sporotrichosis, while S. schenckii was identified only once. The genotype of Sporothrix from cats was found identical to S. brasiliensis from human sources confirming that the disease is transmitted by cats. Sporothrix brasiliensis presented low genetic diversity compared to its sister taxon S. schenckii. No evidence of recombination in S. brasiliensis was found by split decomposition or PHI-test analysis, suggesting that S. brasiliensis is a clonal species. Strains recovered in states SP, MG and PR share the genotype of the RJ outbreak, different from the RS clone. The occurrence of separate genotypes among strains indicated that the Brazilian S. brasiliensis epidemic has at least two distinct sources. We suggest that cats represent a major host and the main source of cat and human S. brasiliensis infections in Brazil.