Passive restoration in Araucaria Forest: useful ecological indicators in monitoring successional advancement in exotic tree plantation landscapes

Monitoring successional advancement is a complex field involving a constant search for applied ecological indicators which facilitate monitoring of secondary forests for both active and passive restoration. In this study, the authors investigate the successional advancement of floristics and tree structure within Araucaria Forest (AF) fragments under passive restoration in a context where exotic tree plantations (mainly Pinus L. genus) dominate the landscape. The ecological indicators used were floristic dissimilarity (β‐diversity inferences), indicator species, ecological groups of species, basal area, and species abundance distribution (SAD) models (α‐diversity inferences). A total of 182 tree species belonging to 91 genera and 43 botanical families were identified. A high β diversity was verified for which each site has indicator species (for the locations CD—Dicksonia sellowiana; CO—Cryptocarya aschersoniana; and PG—Pinus taeda), where pioneer species contributed to much of the abundance. Different SAD models are useful for describing passive restoration sites in exotic tree plantation landscapes, namely Lognormal, Mandelbrot, and Zipf. SAD models together with basal area, taxonomic group (e.g. Myrtaceae assemblage), and tree abundance in ecological groups are strategic ecological indicators for monitoring successional advancement in AF.     

Disturbances, elevation, topography and spatial proximity drive vegetation patterns along an altitudinal gradient of a top biodiversity hotspot

The correlation between vegetation patterns (species distribution and richness) and altitudinal variation has been widely reported for tropical forests, thereby providing theoretical basis for biodiversity conservation. However, this relationship may have been oversimplified, as many other factors may influence vegetation patterns, such as disturbances, topography and geographic distance. Considering these other factors, our primary question was: is there a vegetation pattern associated with substantial altitudinal variation (10–1,093 m a.s.l.) in the Atlantic Rainforest—a top hotspot for biodiversity conservation—and, if so, what are the main factors driving this pattern? We addressed this question by sampling 11 1-ha plots, applying multivariate methods, correlations and variance partitioning. The Restinga (forest on sandbanks along the coastal plains of Brazil) and a lowland area that was selectively logged 40 years ago were floristically isolated from the other plots. The maximum species richness (>200 spp. per hectare) occurred at approximately 350 m a.s.l. (submontane forest). Gaps, multiple stemmed trees, average elevation and the standard deviation of the slope significantly affected the vegetation pattern. Spatial proximity also influenced the vegetation pattern as a structuring environmental variable or via dispersal constraints. Our results clarify, for the first time, the key variables that drive species distribution and richness across a large altitudinal range within the Atlantic Rainforest.     

Acetaminophen in the post-ischemia reperfused myocardium

Acetaminophen was administered acutely at the onset of reperfusion after 20 min of low-flow, global myocardial ischemia in isolated, perfused guinea pig hearts (Langendorff) to evaluate its influence in the postischemia, reperfused myocardium. Similarly prepared hearts were treated with vehicle or with uric acid (another phenol for comparison). Functionally, acetaminophen-treated hearts (0.35 mM) achieved significantly greater recovery during reperfusion. For example, left ventricular developed pressures at 40 min reperfusion were 38 +/- 3, 27 +/- 3, and 20 +/- 2 in the presence of acetaminophen (P < 0.05, relative to the other two groups), vehicle, and uric acid, respectively. Coronary perfusion pressures and calculated coronary vascular resistances, in the acetaminophen-treated hearts, were significantly lower at the same time (e.g., coronary perfusion pressures in the three groups, respectively, were 40 +/- 2 [P < 0.05], 51 +/- 3, and 65 +/- 12 mm Hg). Under baseline, control conditions, creatine kinase ranged from 12-15 units/liter in the three groups. It increased to 35-40 units/liter (P < 0.05) during ischemia but was significantly reduced by acetaminophen during reperfusion (e.g., 5.3 +/- 0.8 units/liter at 40 min). Oxidant-mediated chemiluminescence in all three treatment groups during baseline conditions and ischemia was similar (i.e., approximately 1.5-2.0 min for peak luminescence to reach its half maximal value). It took significantly more time during reperfusion for the oxidation of luminol in the presence of acetaminophen (>20 min, P < 0.05) than in its absence (3-8 min in uric acid- and vehicle-treated hearts). These results suggest that administration of acetaminophen (0.35 mM), at the onset of reperfusion, provides anti-oxidant-mediated cardioprotection in the postischemia, reperfused myocardium.     

The expression of nifB gene from Herbaspirillum seropedicae is dependent upon the NifA and RpoN proteins

The putative nifB promoter region of Herbaspirillum seropedicae contained two sequences homologous to NifA-binding site and a -24/-12 type promoter. A nifB::lacZ fusion was assayed in the backgrounds of both Escherichia coli and H. seropedicae. In E. coli, the expression of nifB::lacZ occurred only in the presence of functional rpoN and Klebsiella pneumoniae nifA genes. In addition, the integration host factor (IHF) stimulated the expression of the nifB::lacZ fusion in this background. In H. seropedicae, nifB expression occurred only in the absence of ammonium and under low levels of oxygen, and it was shown to be strictly dependent on NifA. DNA band shift experiments showed that purified K. pneumoniae RpoN and E. coli IHF proteins were capable of binding to the nifB promoter region, and in vivo dimethylsulfate footprinting showed that NifA binds to both NifA-binding sites. These results strongly suggest that the expression of the nifB promoter of H. seropedicae is dependent on the NifA and RpoN proteins and that the IHF protein stimulates NifA activation of nifB promoter.     

Haploinsufficiency of a spliceosomal GTPase encoded by EFTUD2 causes mandibulofacial dysostosis with microcephaly

Mandibulofacial dysostosis with microcephaly (MFDM) is a rare sporadic syndrome comprising craniofacial malformations, microcephaly, developmental delay, and a recognizable dysmorphic appearance. Major sequelae, including choanal atresia, sensorineural hearing loss, and cleft palate, each occur in a significant proportion of affected individuals. We present detailed clinical findings in 12 unrelated individuals with MFDM; these 12 individuals compose the largest reported cohort to date. To define the etiology of MFDM, we employed whole-exome sequencing of four unrelated affected individuals and identified heterozygous mutations or deletions of EFTUD2 in all four. Validation studies of eight additional individuals with MFDM demonstrated causative EFTUD2 mutations in all affected individuals tested. A range of EFTUD2-mutation types, including null alleles and frameshifts, is seen in MFDM, consistent with haploinsufficiency; segregation is de novo in all cases assessed to date. U5-116kD, the protein encoded by EFTUD2, is a highly conserved spliceosomal GTPase with a central regulatory role in catalytic splicing and post-splicing-complex disassembly. MFDM is the first multiple-malformation syndrome attributed to a defect of the major spliceosome. Our findings significantly extend the range of reported spliceosomal phenotypes in humans and pave the way for further investigation in related conditions such as Treacher Collins syndrome.     

Microbial reduction of cyclohexanones

A Brazilian strain of the bacteria Serratia rubidaea CCT 5742 quantitatively reduced 4-tert-butylcyclohexanone and 4-methylcyclohexanone to the less thermodynamically stable diastereoisomeric alcohols cis-4-tert-butylcyclohexanol and cis-4-methylcyclohexanol with a diastereoisomeric excesses (de) of 96% and 44%, respectively. 2-Methylcyclohexanone was also totally reduced to the corresponding alcohols affording the trans-(+)-(1S, 2S)-2-methylcyclohexanol with 78% of de and an enantiomeric excess (ee) of 80%. The cis-(+)-(1S, 2R)-2-methylcyclohexanol was obtained in 98% ee.     

Heteropolarity in unicellular cyanobacteria: structure and development ofCyanocystis violacea

Cyanocystis violacea isolated from a marine rock sample conforms with the diagnosis ofDermocarpa violacea Crouan in all significant characteristics. The distinct heteropolarity of the cells and simultaneous cell divisions, are stable characters in culture. Development and growth of cells, simultaneous cell division and nanocyte formation have been documented by single-cell slide cultures and fine structural studies. The reddish violet color of the cytoplasm is due to the abundance of phycoerythrin.This paper is dedicated to Prof. DrLothar Geitler, whose monumental contribution to the knowledge of blue-green algae will remain the basis for future studies on these organisms for many years to come. One of us (EIF) was fortunate enough to have had Prof.Geitler as his major professor. All of us consider Prof.Geitler our teacher.     

Modeling the Electric Potential across Neuronal Membranes: The Effect of Fixed Charges on Spinal Ganglion Neurons and Neuroblastoma Cells

We present a model for the electric potential profile across the membranes of neuronal cells. We considered the resting and action potential states, and analyzed the influence of fixed charges of the membrane on its electric potential, based on experimental values of membrane properties of the spinal ganglion neuron and the neuroblastoma cell. The spinal ganglion neuron represents a healthy neuron, and the neuroblastoma cell, which is tumorous, represents a pathological neuron. We numerically solved the non-linear Poisson-Boltzmann equation for the regions of the membrane model we have adopted, by considering the densities of charges dissolved in an electrolytic solution and fixed on both glycocalyx and cytoplasmic proteins. Our model predicts that there is a difference in the behavior of the electric potential profiles of the two types of cells, in response to changes in charge concentrations in the membrane. Our results also describe an insensitivity of the neuroblastoma cell membrane, as observed in some biological experiments. This electrical property may be responsible for the low pharmacological response of the neuroblastoma to certain chemotherapeutic treatments.     

Screening of plant growth promotion ability among bacteria isolated from field-grown sorghum under different managements in Brazilian drylands

Sorghum [Sorghum bicolor (L.) Moench] is a multipurpose grass cultivated in drylands due to its adaptation to drought. However the characteristics of sorghum-associated bacteria are not known in the Brazilian drylands. The aim of this study was to isolate and evaluate the plant growth promotion potential bacteria from field-grown sorghum under two irrigation and manure application levels in a Brazilian semi-arid reagion. Sorghum was irrigated with 3 or 1 mm day^?1 and fertilized or not with liquid goat manure. Bacteria were obtained from surface-disinfected roots applying two nitrogen-free semi-solid media. The bacteria were evaluated for the presence of nifH gene, 16S rRNA sequences, calcium-phosphate solubilization, production of auxins and siderophores and for sorghum growth promotion. We obtained 20 out of 24 positive bacteria for nifH. The isolates were classified as in six different genera. All isolates produced auxins “in vitro”, six bacteria produced siderophores and three Enterobacteriaceae solubilized calcium-phosphate. At least ten bacteria resulted in the increased total N content in the sorghum shoots, comparable to fertilization with 50 mg N plant^?1 week^?1 and to inoculation with Azospirillum brasilense Ab-V5. Enterobacter sp. ESA 57 was the best sorghum plant-growth promoting bacteria isolated in this study.