Disentangling the pathways of land use impacts on the functional structure of fish assemblages in Amazon streams

Agricultural land use is a primary driver of environmental impacts on streams. However, the causal processes that shape these impacts operate through multiple pathways and at several spatial scales. This complexity undermines the development of more effective management approaches, and illustrates the need for more in‐depth studies to assess the mechanisms that determine changes in stream biodiversity. Here we present results of the most comprehensive multi‐scale assessment of the biological condition of streams in the Amazon to date, examining functional responses of fish assemblages to land use. We sampled fish assemblages from two large human‐modified regions, and characterized stream conditions by physical habitat attributes and key landscape‐change variables, including density of road crossings (i.e. riverscape fragmentation), deforestation, and agricultural intensification. Fish species were functionally characterized using ecomorphological traits describing feeding, locomotion, and habitat preferences, and these traits were used to derive indices that quantitatively describe the functional structure of the assemblages. Using structural equation modeling, we disentangled multiple drivers operating at different spatial scales, identifying causal pathways that significantly affect stream condition and the structure of the fish assemblages. Deforestation at catchment and riparian network scales altered the channel morphology and the stream bottom structure, changing the functional identity of assemblages. Local deforestation reduced the functional evenness of assemblages (i.e. increased dominance of specific trait combinations) mediated by expansion of aquatic vegetation cover. Riverscape fragmentation reduced functional richness, evenness and divergence, suggesting a trend toward functional homogenization and a reduced range of ecological niches within assemblages following the loss of regional connectivity. These results underscore the often‐unrecognized importance of different land use changes, each of which can have marked effects on stream biodiversity. We draw on the relationships observed herein to suggest priorities for the improved management of stream systems in the multiple‐use landscapes that predominate in human‐modified tropical forests.     

Understanding genetic diversity,spatial genetic structure,and mating system through microsatellite markers for the conservation and sustainable use of <Emphasis Type="Italic">Acrocomia aculeata</Emphasis> (Jacq.) Lodd. Ex Mart.

Acrocomia aculeata is a native palm distributed widely throughout Brazil that is used in a diverse array of products from the food industry to biodiesel oil production. This study uses nine microsatellite loci to assess the genetic diversity, spatial genetic structure (SGS), and mating system of A. aculeata. A total of 200 samples were collected from four populations (Fusquinha—FU, Padre Josimo—PJ, Gleba XV-GB, and Amparo—AM), in São Paulo State, Brazil. We also collected fruits from 20 randomly selected seed trees in the FU population to assess mating patterns, for a total of 246 genotyped embryos. We identified a total of 103 alleles and all loci were polymorphic. The average observed heterozygosity (\({H_o}\)) ranged from 0.410 (AM) to 0.531 (FU) and expected heterozygosity (\({H_e}\)) ranged from 0.547 (PJ) to 0.615 (GB). The average fixation index (\(F\)) ranged from 0.043 to 0.254 for FU and AM populations, respectively. The coancestry coefficient (\({\theta _{xy}}\)) was significant up to 38 m in PJ the population and 71 m in AM. Individual palm outcrossing rates were predominantly high (\({t_m}\)?=?0.985) and the paternity correlation (\({r_{{p_{(m)}}}}\)?=?0.02) was significantly low, indicating a high probability of the occurrence of half-sibs. Compared to other palm species, the studied populations show high levels of genetic diversity. Our results confirm that A. aculeata is primarily allogamous, with no significant paternity correlation, and seeds should be harvested from at least 40 trees to ensure high levels of genetic diversity in seed collection programs.     

Molecular weight distribution and structural characteristics of polymers obtained from acid soluble lignin treated by oxidative enzymes

Brown precipitates were obtained by polymerization of low molecular weight lignin fragments contained in a model effluent. Polymerization reactions were initiated by potato-polyphenoloxidase (PPO) or horseradish peroxidase/H(2)O(2) system (HRP/H(2)O(2)). The insolubilization processes occurred after a molecular weight increase of the lignin, as shown by gel permeation chromatography (GPC). The effect of reaction time, pH and amount of soluble lignin per unit of enzyme activity on the molecular weight distribution was evaluated for PPO-initiated reactions. For HRP-initiated system the amount of H(2)O(2) per unit of enzyme activity was also evaluated. Chemical characterization of the macromolecules obtained under optimized conditions and the soluble lignin fragments present in the effluent suggests that the polymerization reactions occur by oxidative cleavage of alpha-beta unsaturated bonds of the soluble lignin fragments. Methoxyl group analysis showed that p-hydroxycoumaryl units were preferentially oxidized by PPO. In contrast, HRP oxidized preferentially guaiacyl and siringyl units giving more condensed polymers.     

Fused mid‐caudal vertebrae in the titanosaur Uberabatitan ribeiroi from the Late Cretaceous of Brazil and other bone lesions

Bone pathology in the titanosaur dinosaur Uberabatitan ribeiroi from the Marília Formation (Bauru Group, Late Cretaceous) of Uberaba city (Minas Gerais State, Brazil) is analysed here. They include two fused procoelous mid‐caudal vertebrae (CPPLIP‐1020) and a haemal arch (CPPLIP‐1006) of the middle section of the tail with a healing fracture callus. The analyses of the caudal vertebrae CPPLIP‐1020 of Uberabatitan permit us to recognize the following signs, based on CT scan and external macroscopic observations: (1) ossified longitudinal tendons; (2) likely ossified intervertebral disc, producing fused vertebral bodies; (3) fused right zygapophyseal process with a laterally developed osteophyte affecting this joint; (4) osteophytes and exostoses at different portions of the vertebrae; (5) cloacae, bone erosion and likely internal infection. According to all the processes observed in these caudals, we could not discard at least two possibilities for the diagnosis of the fused vertebrae. It could be the result of a spondyloarthropathy process (considering most of the observed signs) or possibly have been associated with an infection (e.g. discospondylitis/infections spondylitis or septic arthritis). The bone lesion record in Uberabatitan ribeiroi from the Late Cretaceous of Brazil increases the range of study of titanosaur dinosaurs, which although have a large fossil record, have few pathological studies.     

Activation and cytokine profile of monocyte derived dendritic cells in leprosy: in vitro stimulation by sonicated Mycobacterium leprae induces decreased level of IL-12p70 in lepromatous leprosy

Dendritic cells (DCs) play a pivotal role in the connection of innate and adaptive immunity of hosts to mycobacterial infection. Studies on the interaction of monocyte-derived DCs (MO-DCs) using Mycobacterium leprae in leprosy patients are rare. The present study demonstrated that the differentiation of MOs to DCs was similar in all forms of leprosy compared to normal healthy individuals. In vitro stimulation of immature MO-DCs with sonicated M. leprae induced variable degrees of DC maturation as determined by the increased expression of HLA-DR, CD40, CD80 and CD86, but not CD83, in all studied groups. The production of different cytokines by the MO-DCs appeared similar in all of the studied groups under similar conditions. However, the production of interleukin (IL)-12p70 by MO-DCs from lepromatous (LL) leprosy patients after in vitro stimulation with M. leprae was lower than tuberculoid leprosy patients and healthy individuals, even after CD40 ligation with CD40 ligand-transfected cells. The present cumulative findings suggest that the MO-DCs of LL patients are generally a weak producer of IL-12p70 despite the moderate activating properties ofM. leprae. These results may explain the poor M. leprae-specific cell-mediated immunity in the LL type of leprosy.     

Genetic parameters for growth traits of a Brazilian Bos taurus x Bos indicus beef composite

The genetic analysis of composite data is very complicated, mainly because it is necessary to adjust data to the effects of heterosis and breed complementarity, and because there is usually considerable confounding of these data with several other effects, such as contemporary group effects, breed composition of the animal and maternal breed composition, among others. Data on birth weight (n = 151,083), weaning weight adjusted to 205 days (n = 137,257), yearling weight adjusted to 390 days (n = 61,410), weight gain from weaning to yearling (n = 56,653), and scrotum circumference (n = 23,323) and muscle score (n = 54,770), both adjusted to 390 days, from Bos taurus x Bos indicus composite beef calves born from 1994 to 2003 were analyzed to estimate (co)variance components and genetic parameters of growth traits. The animals belonged to the Montana Tropical program. Estimation was made by three models that approach adjustment to heterozygosis in order to suggest the best model. The RM model included contemporary groups, class of age of dam, outcrossing percentages for direct and maternal effects, and direct and maternal additive genetic breed effects as covariates; the R model was the same as RM, but without additive maternal breed effects, and H was the same as RM, but not considering any additive breed effect. Both R2 values and consistency of genetic parameters indicate that the more complex model (RM), which considers maternal and individual additive genetic breed effect, produces the best estimates when compared to other models. The R model seems to overestimate (co)variance components. The magnitudes of direct and maternal heritability estimates, obtained in this study, would permit genetic improvement for weight and growth traits, as much by selection of direct genetic effects for weight and growth as for the improvement of maternal performance, but in different lineages. Therefore, the correlations between these effects were unfavorable.     

Genetic trends of absolute and relative heart weight in a male broiler line

Data of chickens from a broiler-breeding program have been collected and used for determination of genetic trends of absolute and relative heart weight. The genetic trends have been estimated by regression of the genetic values of the traits over hatch-year. Genetic values of 42,912 individuals, obtained by restricted maximum likelihood, were used for regression analysis. The estimates of the genetic trends for absolute and relative heart weight were found to be -0.08 g and -0.004% per hatch-year, respectively. These trends show that heart weight in the line analyzed, in absolute and relative terms, has tended to decrease, which can make the metabolic disorders due to the reduction in heart weight in broilers even worse.     

Taxonomic,functional, and phylogenetic β‐diversity patterns of stream fish assemblages in tropical agroecosystems

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