Morphological affinities of the Australopithecus afarensis hand on the basis of manual proportions and relative thumb length

The hands of apes and humans differ considerably with regard to proportions between several bones. Of critical significance is the long thumb relative to other fingers, which is the basis for human-like pad-to-pad precision grip capability, and has been considered by some as evidence of tool-making. The nature and timing of the evolutionary transition from ape-like to human-like manual proportions, however, have remained unclear as a result of the lack of appropriate fossil material. In this article, the manual proportions of Australopithecus afarensis from locality AL 333/333w (Hadar, Ethiopia) are investigated by means of bivariate and multivariate morphometric analyses, in order to test the hypothesis that human-like proportions, including an enhanced thumb/hand relationship, originally evolved as an adaptation to stone tool-making. Although some evidence for human-like manual proportions had been previously proposed for this taxon, conclusive evidence was lacking. Our results indicate that A. afarensis possessed overall manual proportions, including an increased thumb/hand relationship that, contrary to previous reports, is fully human and would have permitted pad-to-pad human-like precision grip capability. We show that these human-like proportions in A. afarensis mainly result from hand shortening, as in modern humans, and that these conclusions are robust enough as to be non-dependent on whether the bones belong to a single individual or not. Since A. afarensis predates the appearance of stone tools in the archeological record, the above-mentioned conclusions permit a confident refutation of the null hypothesis that human-like manual proportions are an adaptation to stone tool-making, and thus alternative explanations must be therefore sought. One hypothesis would consider manipulative behaviors (including tool-use and/or non-lithic tool-making) in early hominines exceeding those reported among extant non-human primates. Alternatively, on the basis of the many adaptations to committed bipedalism in A. afarensis, we propose the hypothesis that once arboreal behaviors became adaptively insignificant and forelimb-dominated locomotor selection pressures were relaxed with the adoption of terrestrial bipedalism, human-like manual proportions could have merely evolved as a result of the complex manipulation selection pressures already present in extant non-human primates.Both hypotheses are not mutually exclusive, and even other factors such as pleiotropy cannot be currently discarded.     

Contribution of functional voltage-gated Na+ channel expression to cell behaviors involved in the metastatic cascade in rat prostate cancer: I. Lateral motility

Previous work suggested that functional voltage-gated Na(+) channels (VGSCs) are expressed specifically in strongly metastatic cells of rat and human prostate cancer (PCa), thereby raising the possibility that VGSC activity could be involved in cellular behavior(s) related to the metastatic cascade. In the present study, the possible role of VGSCs in the lateral motility of rat PCa cells was investigated in vitro by testing the effect of modulators that either block or enhance VGSC activity. Two rat PCa cell lines of markedly different metastatic ability were used in a comparative approach: the strongly metastatic MAT-LyLu and the weakly metastatic AT-2 cell line, only the former being known to express functional VGSCs. Using both electrophysiological recording and a motility assay, the effects of two VGSC blockers (tetrodotoxin and phenytoin) and four potential openers (veratridine, aconitine, ATX II, and brevetoxin) were monitored on (a) Na(+) channel activity and (b) cell motility over 48 h. Tetrodotoxin (at 1 microM) and phenytoin (at 50 microM) both decreased the motility index of the MAT-LyLu cell line by 47 and 11%, respectively. Veratridine (at 20 microM) and brevetoxin (at 10 nM) had no effect on the motility of either cell line, whilst aconitine (at 100 microM) and ATX II (at 25 pM) significantly increased the motility of the MAT-LyLu cell line by 15 and 9%, respectively. Importantly, at the concentrations used, none of these drugs had effects on the proliferation or viability of either cell line. The results, taken together, would suggest strongly that functional VGSC expression enhances cellular motility of PCa cells. The relevance of these findings to the metastatic process in PCa is discussed.     

The amino acid precursors and odor formation in society garlic (Tulbaghia violacea Harv.)

Identification and isolation of (R(S)R(C))-S-(methylthiomethyl)cysteine-4-oxide from rhizomes of Tulbaghia violacea Harv. is reported. The structure and absolute configuration of the amino acid have been determined by NMR, MALDI-HRMS, IR, and CD spectroscopy. Its content varied in different parts of the plant (rhizomes, leaves, and stems) between 0.12 and 0.24 mg g(-1) fr. wt, being almost equal in the stems and rhizomes. In addition, S-methyl- and S-ethylcysteine derivatives have been detected in minute amounts (<3 microg g(-1) fr. wt) in all parts of the plant. The enzymatic cleavage of the amino acid and subsequent odor formation are discussed. 2,4,5,7-Tetrathiaoctane-4-oxide, the primary breakdown product, has been detected and isolated for the first time.     

A new species of Devosia that forms a unique nitrogen-fixing root-nodule symbiosis with the aquatic legume Neptunia natans (L.f.) druce

Rhizobia are the common bacterial symbionts that form nitrogen-fixing root nodules in legumes. However, recently other bacteria have been shown to nodulate and fix nitrogen symbiotically with these plants. Neptunia natans is an aquatic legume indigenous to tropical and subtropical regions and in African soils is nodulated by Allorhizobium undicola. This legume develops an unusual root-nodule symbiosis on floating stems in aquatic environments through a unique infection process. Here, we analyzed the low-molecular-weight RNA and 16S ribosomal DNA (rDNA) sequence of the same fast-growing isolates from India that were previously used to define the developmental morphology of the unique infection process in this symbiosis with N. natans and found that they are phylogenetically located in the genus Devosia, not Allorhizobium or RHIZOBIUM: The 16S rDNA sequences of these two Neptunia-nodulating Devosia strains differ from the only species currently described in that genus, Devosia riboflavina. From the same isolated colonies, we also located their nodD and nifH genes involved in nodulation and nitrogen fixation on a plasmid of approximately 170 kb. Sequence analysis showed that their nodD and nifH genes are most closely related to nodD and nifH of Rhizobium tropici, suggesting that this newly described Neptunia-nodulating Devosia species may have acquired these symbiotic genes by horizontal transfer.     

Extent of variation of the Bacillus thuringiensis toxin reservoir: the case of the geranium bronze,Cacyreus marshalli butler (Lepidoptera: Lycaenidae)

Despite the fact that around 200 cry genes from Bacillus thuringiensis have already been cloned, only a few Cry proteins are toxic towards a given pest. A crucial step in the mode of action of Cry proteins is binding to specific sites in the midgut of susceptible insects. Binding studies in insects that have developed cross-resistance discourage the combined use of Cry proteins sharing the same binding site. If resistance management strategies are to be implemented, the arsenal of Cry proteins suitable to control a given pest may be not so vast as it might seem at first. The present study evaluates the potential of B. thuringiensis for the control of a new pest, the geranium bronze (Cacyreus marshalli Butler), a butterfly that is threatening the popularity of geraniums in Spain. Eleven of the most common Cry proteins from the three lepidopteran-active Cry families (Cry1, Cry2, and Cry9) were tested against the geranium bronze for their toxicity and binding site relationships. Using 125I-labeled Cry1A proteins we found that, of the seven most active Cry proteins, six competed for binding to the same site. For the long-term control of the geranium bronze with B. thuringiensis-based insecticides it would be advisable to combine any of the Cry proteins sharing the binding site (preferably Cry1Ab, since it is the most toxic) with those not competing for the same site. Cry1Ba would be the best choice of these proteins, since it is significantly more toxic than the others not binding to the common site.     

Propranolol blocks the tachycardia induced by galanin (1-15) but not by galanin (1-29)

The efferent pathways involved in the tachycardia induced by intracisternal injections of the N-terminal galanin fragment (1-15) (GAL (1-15)) and galanin (GAL (1-29)) has been evaluated in rats pretreated with the cholinergic antagonist atropine or the beta-antagonist propranolol. The pretreatment with propranolol significantly blocked the tachycardic and vasopressor effect produced by intracisternal injection of GAL (1-15) (p<0.05), but the pretreatment with atropine did not modify these cardiovascular effects. However, the cardiovascular response elicited by GAL (1-29) is modified by the pretreatment with atropine (p<0.05) but not by propranolol. These findings demonstrate that the central cardiovascular action of GAL (1-15), but not GAL (1-29), is mediated by beta-receptor stimulation and this suggests the existence of a different pathway involved in the cardiovascular response produced by the N-terminal galanin fragment as compared with the parent molecule GAL (1-29).     

Targeting of carbonic anhydrase IV to plasma membranes is altered in cultured human pancreatic duct cells expressing a mutated (deltaF508) CFTR

Human pancreatic duct cells secrete HCO3- ions mediated by a Cl-/HCO3- exchanger and a HCO3- channel that may be a carbonic anhydrase IV (CA IV) in a channel-like conformation. This secretion is regulated by CFTR (Cystic Fibrosis Transmembrane conductance Regulator). In CF cells homozygous for the deltaF508 mutation, the defect in targeting of CFTR to plasma membranes leads to a disruption in the secretion of Cl- and HCO3 ions along with a defective targeting of other proteins. In this study, we analyzed the targeting of membrane CA IV in the human pancreatic duct cell line CFPAC-1, which expresses a deltaF508 CFTR, and in the same cells transfected with the wild-type CFTR (CFPAC-PLJ-CFTR6) or with the vector alone (CFPAC-PLJ6). The experiments were conducted on cells in the stationary phase the polarized state of which was checked by the distribution of occludin and actin. We show that both cell lines express a 35-kDa CA IV at comparable levels. Analysis of fractions of plasma membranes purified on a Percoll gradient evidenced lower levels of CA IV (8-fold) in the CFPAC-1 than in the CFPAC-PLJ-CFTR6 cells. Quantitative analyses showed that 6- to 10-fold fewer cells in the CFPAC-1 cell line exhibited membrane CA IV-immunoreactivity than in the CFPAC-PLJ-CFTR6 cell line. Taken together, these results suggest that the targeting of CA IV to apical plasma membranes is impaired in CFPAC-1 cells. CA IV/gamma-adaptin double labeling demonstrated the presence of CA IV in the trans-Golgi network (TGN) of numerous CFPAC-1 cells, indicating that trafficking was disrupted on the exit face of the TGN. The retargeting of CA IV observed in CFPAC-PLJ-CFTR6 cells points to a relationship between the traffic of CFTR and CA IV. On the basis of these observations, we propose that the absence of CA IV in apical plasma membranes due to the impairment in targeting in cells expressing a deltaAF508 CFTR largely contributes to the disruption in HCO3- secretion in CF epithelia.     

Soils of the Chinese Hubei province show a very high diversity of Sinorhizobium fredii strains

Biodiversity studies of native soybean-nodulating rhizobia in soils from the Chinese Hubei province (Honghu county; pH 8, alluvial soil) have been carried out. Inoculation of an American (Williams) and an Asiatic (Peking) soybean cultivar with eleven soil samples led to the isolation of 167 rhizobia strains. The ratio (%) of slow-/fast-growing isolates was different depending on the trap plant used. All isolates were able to nodulate both cultivars, although the N2-fixation efficiency (measured as plant-top dry weight) was different among them. A total of thirty-three isolates were selected for further characterisation on the basis of physiological parameters, PCR-RFLP of symbiotic genes and Low Molecular Weight RNA, lipopolysaccharide, protein and plasmid profiles. Low Molecular Weight RNA profiling indicates that all the isolates belong to species Sinorhizobium fredii. The dendrogram obtained with the physiological parameters has been useful to classify the isolates at strain level, although plasmid profiling was the most discriminating technique to detect differences among the analysed soybean-rhizobia isolates, showing there is not two isolates identical each other. Plasmid profile analyses also revealed that some of the investigated strains contain low molecular weight plasmids (7-8-kb). They are, to our knowledge, the smallest ever found in rhizobia and they could be the starting point for the construction of the first group of vectors based on a native rhizobia replicon.     

Altitudinal distribution patterns of Mexican cloud forests based upon preferential characteristic genera

Mexican cloud forest vegetation has been recorded in temperate humidconditions at rather different elevations ranging from 600 to 3000m. They are characterised by high biodiversity under continuousfoggy situations. Some authors state that many genera are quantitativelyimportant to depict cloud forest conditions. Detailed quantitative studiescomprising most of the localities of Mexican cloud forests to depict altidudinaldistribution ranges on basis of preferential genera have not been previouslyconducted. The aim of this study is (1) to recognise characteristic preferentialgenera of Mexican cloud forest conditions, and (2) to determine quantitativelythe current altitudinal distribution pattern of this vegetation type. From adatabase composed by 995 genera inhabiting in the Mexican cloud forests, sixgenera were chosen preliminary as preferential characteristics. These wereClethra, Magnolia, Meliosma, Styrax, Symplocos, andTernstroemia. These genera include 70 species that occur atover 70% of the current Mexican cloud forest fragments. The mean elevation ofthese genera records were 1853 m (±600 at 95% confidenceinterval). The results showed that Mexican cloud forests occur optimally between1250 and 2450 m. Additionally, Mexican cloud forest is the bestdistributed within some provinces of the Región Mesoamericana deMontaña, chiefly at Serranías Meridionales,Sierra Madre Oriental, and SerraníasTransístmicas. The results are discussed in light of theimportance of these regions as diversification centres.