Fruit biomass availability along a forest cover gradient

Habitat loss is the main driver of the current high rate of species extinction, particularly in tropical forests. Understanding the factors associated with biodiversity loss, such as the extinction of species interactions and ecological functions, is an urgent priority. Here, our aim was to evaluate how landscape‐scale forest cover influences fruit biomass comparing different tree functional groups. We sampled 20 forest fragments located within landscapes with forest cover ranging from 2 to 93 percent in the Atlantic forest of southern Bahia, Brazil. In each fragment, we established five plots of 25 × 4 m and carried out phenological observations on fleshy fruit throughout 1 year on all trees ≥5 cm dbh. We estimated fruit availability by direct counting of all fruits and derived fruit biomass from this count. We used spatial mixed linear models to evaluate the effects of forest cover on species richness, abundance, and fruit biomass. Our results indicated that forest cover was the main explanatory variable and negatively influenced the total richness and abundance of zoochoric and shade‐tolerant but not shade‐intolerant species. A linear model best explained variations in richness and abundance of total and shade‐tolerant species. We also found that forest cover was positively correlated with the fruit biomass produced by all species and by the shade‐tolerant assemblages, with linear models best explaining both relationships. The loss of shade‐tolerant species and the lower fruit production in fragments with lower landscape‐scale forest cover may have implications for the maintenance of frugivore, seed dispersal service, and plant recruitment.     

A new <Emphasis Type="Italic">Heteropterys</Emphasis> (Malpighiaceae) from semideciduous forest,with notes on wood anatomy

This paper describes and illustrates Heteropterys serrata, a new species endemic to semideciduous forests associated with inselbergs in the state of Espírito Santo, Brazil. Morphological and wood anatomical traits of the new species are compared to those of other species of the Heteropterys Metallophyllis informal group. Based on wood anatomy, H. serrata and H. nitida (the most morphologically similar species) have different axial parenchyma, which is scarce paratracheal in H. nitida (and some other species of the Metallophyllis informal group) and aliform confluent in H. serrata. The most notable morphological and anatomical characters that distinguish the new species are the young hexagonal stems, the unusual widely serrate leaf margins and the aliform confluent axial parenchyma in the wood.     

Negligence in the Atlantic forest,northern Brazil: a case study of an endangered orchid

Currently, many Brazilian orchids are threatened with extinction resulting from habitat loss and intense harvesting pressure stemming from their value as ornamental plants. Therefore, the genetic diversity in remaining populations is fundamental to the survival of these species in natural environments. In order to inform conservation strategies, this study evaluated the genetic diversity and structure of Cattleya granulosa populations. The sample consisted of 151 individuals from 12 populations in the Atlantic Forest, northeastern Brazil, evaluated using 91 ISSR markers. Genetic variability was assessed through molecular variance, diversity indexes, clusters of genotypes through Bayesian analysis, and tests for genetic bottlenecks. From all polymorphic loci, genetic diversity (H_E) varied between 0.210 and 0.321 and the Shannon index ranged from 0.323 and 0.472. Significant genetic differentiation between populations (Φ_ST = 0.391; P < 0.0001) resulted in the division of the populations into five groups based on the log-likelihood Bayesian analysis. We found significant positive correlation between geographical and genetic distances between populations (r = 0.794; P = 0.017), indicating isolation by distance. Patterns of allelic diversity within populations suggest the occurrence of bottlenecks in most C. granulosa populations (n = 8). Therefore, in order to maintain the genetic diversity of the species, the conservation of spatially distant groups is necessary.     

Model investigations for vanadium-protein interactions: vanadium(III) compounds with dipeptides and their oxovanadium(IV) analogues

The reaction of VCl(3) with 1,10-phenanthroline and a series of dipeptides (H(2)dip), having aliphatic as well as aromatic side chains, in methyl alcohol and in the presence of triethylamine affords vanadium(III) compounds of the general formula [V(III)(dip)(MeOH)(phen)]Cl. Aerial oxidation/hydrolysis of the vanadium(III) species gives their oxovanadium(IV) analogues of the general formula [V(IV)O(dip)(phen)]. X-ray crystallographic characterization of the [V(IV)O(dip)(phen)] compounds (where dip(2-)=Gly- L-Ala, Gly- L-Val and Gly- L-Phe) revealed that the vanadium atom possesses a severely distorted octahedral coordination and is ligated to a tridentate dip(2-) ligand at the N(amine) atom, the deprotonated N(peptide) atom and one of the O(carboxylate) atoms, as well as an oxo group and two phenanthroline nitrogen atoms. Circular dichroism characterization of the V(III)/V(IV)O(2+)-dipeptide compounds revealed a strong signal for the V(IV)O(2+) species in the visible range of the spectrum, with a characteristic pattern which may be exploited to identify the N(am), N(pep) and O(car) ligation of a peptide or a protein to V(IV)O(2+) center, and a weak Cotton effect of opposite sign to their vanadium(III) analogues. The visible spectra of the V(III)-dipeptide compounds revealed two d-d bands with high intensity, thus indicating that the covalency of the metal-donor atoms is significant, i.e. the vanadium d orbitals are significantly mixed with the ligand orbitals, and this is confirmed by the low values of their Racah B parameters. The high-intensity band of the V(IV)O(2+)-dipeptide compounds at approximately 460 nm implies also a strong covalency of the metal with the equatorial donor atoms and this was supported by the EPR spectra of these compounds. Moreover, the V(III)/V(IV)O(2+)-dipeptide complexes were characterized by EPR and IR spectroscopies as well as conductivity and magnetic susceptibility measurements.     

Influences of FSH and EGF on primordial follicles during in vitro culture of caprine ovarian cortical tissue

Factors that control the onset of folliculogenesis are critical to female gamete production, but poorly understood. The aim of the present study was to investigate the effects of FSH and EGF on the activation and growth of goat primordial follicles in vitro. To this end, pieces of goat ovarian cortex were cultured in vitro for 1, 3 or 5 days, at 39 degrees C in an atmosphere containing 5% CO(2), in minimum essential medium supplemented with insulin, transferrin, selenium, pyruvate, glutamine, hypoxanthine, BSA, penicillin, streptomycin and fungizone and with or without FSH (100 ng/ml) and/or EGF (100 ng/ml). At the end of the culture periods, the relative proportions of primordial, intermediate, primary and secondary follicles were calculated and compared with those in non-cultured tissue. In addition, mitotic activity of granulosa cells was studied by immunohistochemistry for proliferating cell nuclear antigen (PCNA). In brief, it was found that goat primordial follicles activate spontaneously during culture in vitro and, while neither FSH nor EGF affected the proportion of primordial follicles that entered the growth phase, both stimulated an increase in oocyte and follicle diameter, especially in intermediate and primary follicles cultured for 5 days. On the other hand, there was no significant effect of culture or either growth factor on the proportion of PCNA-stained growing follicles. Contrary to expectations, neither FSH nor EGF affected follicle viability or integrity during culture, since the percentages of intact follicles did not differ between control, FSH and/or EGF containing medium. In conclusion, this study demonstrated that goat primordial follicles activate spontaneously in vitro, and that both FSH and EGF stimulate an increase in follicle size by promoting oocyte growth.     

Cordiachromes from Auxemma oncocalyx

Further cordiachromes, rel-10,11β-epoxy-11-ethoxy-8-hydroxy-2-methoxy-8aβ-methyl-5,6,7,8,8a,9,10aβ-octahydro-1,4-anthracendione, 6-formyl-2-methoxy-9-methyl-7,8-dihydro-1,4-phenanthrendione, rel-8,11;9,11-diepoxy-1,4-dihydroxy-2-methoxy-8aβ-methyl-5,6,7,8,8a,9,10,10aβ-octahydro-10-anthracenone, rel-9,11-epoxy-1,4,8-trihydroxy-2-methoxy-8aβ-methyl-5,6,7,8,8a,9,10,10aβ-octahydro-10-anthracenone, rel-2″-methoxy-7″-methyl-1″,4″-naphtalendione-(6″→5)-tetrahydropyran-(2-eq→O→2ax)-tetrahydropyran-(5′→6)- 2-methoxy-7-methyl-1,4-naphthalendione, together with the known, allantoin, sitosterol and 3β-O-d-glucopyranosylsitosterol, have been isolated from Auxemma oncocalyx. Their structures were determined from spectral data, including 2D NMR experiments.     

The structure of postsynaptic densities isolated from dog cerebral cortex: I. overall morphology and protein composition

A postsynaptic density (PSD) fraction, including some adherent subsynaptic web material, has been isolated from dog cerebral cortex by a short-procedure modification of methods of Davis and Bloom (21, 22) and Cotman and Taylor (20), using Triton X-100. The fraction has been visualized by thin-section, replica, and negative (phosphotungstic acid) staining electron microscopy and its proteins separated by high-resoltuion SDS gel electrophoresis. Morphologically, the preparation seems to be quite pure, with very little membrane contamination. The density is composed of protein, no nuclei acids, and very little phospholipids being detectable. The fraction had no ATPase or GTPase activity, but it did have a very small amount of cytochrome c oxidase activity (of a specific activity less than 0.5 percent that of a mitochondrial fraction) and a small amount of 5'- nucleotidase activity (of a specific activity between 6 and 7 percent that of a synaptic membrane fraction). Electron micrographs reveal cup-shaped structures approximately 400nm long and approximately 40nm wide, made up of apparent particles 13-28nm in diameter. However, en face views, and particularly micrographs of replicas and PTA-stained preparations, reveal a disk-shaped structure, outside diameter approximately 400 nm, in which filaments are seen to extend from the central part of the density. High resolution gel electrophoresis studies indicated some 15 major proteins and perhaps 10 or more minor ones; the predominant protein had a mol wt of 51,000, followed by ones at 45,000, 40,000, 31,000, 26,000, and several at 100,000. A comparison by gel electrophoresis of density fraction proteins with those of a lysed synaptosomal membrane fraction containing some adherent densities indicated some comigrating proteins, but the major membrane fraction protein, mol wt 52,000, was not found in the density fraction. Antibodies raised against the density fraction reacted with a preparation of solubilized synaptic membrane proteins. By both these criteria, it was considered that the density and the synaptic membrane have some proteins in common. By separately mixing (125)I-labeled myelin, synaptic vesicle, and mitochondrial fraction proteins with synaptosomes, and then isolating the density fraction from the mixture, it was concluded that a major 26,000 mol wt density fraction protein was common to both mitochondria and density, that none of the proteins of the density were contaminants from the mitochondrial fraction, that a minor approximately 150,000 band was a contaminant from the synaptic vesicle fraction, and that the moderately staining PSD fraction protein of 17,000 mol wt band was the result of contamination by the major basic protein of myelin. On the basis of the marker enzymatic assays and the mixing experiments, it is considered that the density fraction is moderately pure biochemically, and that its protein composition, aside from a few exceptions noted above, reflects its in situ character.     

The structure of postsynaptic densities isolated from dog cerebral cortex: II. characterization and arrangement of some of the major proteins within the structure

An attempt was made to identify some of the proteins of the postsynaptic density (PSD) fraction isolated from dog cerebral cortex. The major protein has been tentatively labeled "neurofilament" protein, on the basis of its 51,000 mol wt correspondence to a protein found in neurofilament preparations. Other proteins are akin to some dog myofibrillar proteins, on the basis if immunological crossreaction and equal sodium dodecyl sulfate (SDS)-gel electrophoretic mobilities. While a protein similar to dog muscle myosin is not present in the PSD fraction, a major protein present is actin, as evident from reactivity with antiactin serum, from SDS-gel mobility, and from amino acid composition. Only very little tubulin may be present in the PSD fraction, as determined by gel electrophoresis. Various treatments of the PSD fraction were attempted in order to extract some proteins, as revealed by gel electrophoresis, and to observe the structural changes of the PSD fraction residue after extraction of these proteins. The PSD is remarkably resistant to various extraction conditions, with only 4 M guanidine being found to extract most of the proteins, except the 51,000 mol wt protein. Disulfide reducing agents such as dithiothreitol (DTT), blocking agents such as p-chloromercuribenzoate (PCMB) (both in the presence of deoxycholate [DOC]), a Ca++ extractor, ethylene glycol-bis (beta- aminoethyl ether) N,N,N',N'-tetraacetate (EGTA), and guanidine caused an opening up of the native dense PSD structure, revealing approximately 10-nm filaments, presumably consisting of "neurofilament" protein. Both DTT-DOC and PCMB-DOC removed chiefly actin but also some other proteins. EGTA, in greatly opening up the structure, as observed in the electron microscope, revealed both 10-nm and 3- to 5-nm filaments; the later could be composed of actin, since actin was still in the residue after the treatment. EGTA removed a major 18,000 mol wt component and two minor proteins of 68,000 and 73,000 mol wt. Based on the morphological and biochemical evidence, a picture is presented of the PSD as a structure partly made up of 10-nm and 3- to 5-nm filaments, held together through Ca++ interaction and by bonds amendable to breakage by sulfhydrylblocking and disulfide-reducing reagents; either removal of Ca++ and/or rupture of these disulfide bonds opens up the structure. On the basis of the existence of filamentous proteins and the appearance of the PSD after certain treatments as a closed or open structure, a theory is presented with envisages the PSD to function as a modulator in the conduction of the nerve impulse, by movements of its protein relative.