Implications of local knowledge of the ecology of a wild super sweetener for its domestication and commercialization in West and Central Africa

Despite its local use as a fiber and international trade in thaumatin, the intensely sweet protein derived from its fruit, little ecological information aboutThaumatococcus daniellii (Benn.) Benth. is in the public domain. Here, we combine systematic studies of the local knowledge of plant collectors and cultivators in Ghana with a thorough evaluation of the plant’s natural distribution in order to explore possibilities for increasing the contribution that it makes to sustaining rural livelihoods in West and Central Africa. The natural range goes well beyond where commercial collection and cultivation have been previously reported. Local knowledge was found to be detailed and explanatory. Its acquisition has refined our understanding of the ecology of the plant, although some significant gaps remain, particularly with respect to pollination. The market for thaumatin is ripe for expansion, and the plant has untapped potential as an intercrop for rubber and cocoa. Further domestication needs to be accompanied by consideration of impacts on the livelihoods of those who presently collect fruit from the wild, and of opportunities for increasing the value that accrues within Africa through the development of local processing capacity.     

Evolution and diversification of a sexually dimorphic luminescent system in ponyfishes (Teleostei: Leiognathidae), including diagnoses for two new genera

A phylogeny was generated for Leiognathidae, an assemblage of bioluminescent, Indo‐Pacific schooling fishes, using 6175 characters derived from seven mitochondrial genes (16S, COI, ND4, ND5, tRNA‐His, tRNA‐Ser, tRNA‐Leu), two nuclear genes (28S, histone H3), and 15 morphological transformations corresponding to features of the fishes' sexually dimorphic light‐organ system (LOS; e.g., circumesophageal light organ, lateral lining of the gas bladder, transparent flank and opercular patches). Leiognathidae comprises three genera, Gazza, Leiognathus, and Secutor. Our results demonstrate that Leiognathidae, Gazza, and Secutor are monophyletic, whereas Leiognathus is not. The recovered pattern of relationships reveals that a structurally complex, strongly sexually dimorphic and highly variable species‐specific light organ is derived from a comparatively simple non‐dimorphic structure, and that evolution of other sexually dimorphic internal and external features of the male LOS are closely linked with these light‐organ modifications. Our results demonstrate the utility of LOS features, both for recovering phylogeny and resolving taxonomic issues in a clade whose members otherwise exhibit little morphological variation. We diagnose two new leiognathid genera, Photopectoralis and Photoplagios, on the basis of these apomorphic LOS features and also present derived features of the LOS to diagnose several additional leiognathid clades, including Gazza and Secutor. Furthermore, we show that five distinct and highly specialized morphologies for male‐specific lateral luminescence signaling, which exhibit species‐specific variation in structure, have evolved in these otherwise outwardly conservative fishes. Leiognathids inhabit turbid coastal waters with poor visibility and are often captured in mixed assemblages of several species. We hypothesize that the species‐specific, sexually dimorphic internal and external modifications of the leiognathid LOS provide compelling evidence for an assortative mating scheme in which males use species‐specific patterns of lateral luminescence signaling to attract mates, and that this system functions to maintain reproductive isolation in these turbid coastal environments. © The Willi Hennig Society 2005.     

Current Status for High Titre Poxvirus Stock Preparation in CEF Under Serum-Free Medium Conditions: Implication for Vaccine Development

In light of the recent detection of BSE in North America and its endemic nature in other regions of the world, there is a real need to employ cell culture conditions that do not require any animal-derived material. Here we report the use of an ultra-low protein serum-free medium (VP-SFM, Invitrogen) for the amplification of poxviruses in primary chicken embryo fibroblasts (CEF). We compared the amplification of four different poxviruses (canarypox, modified Ankara Virus (MVA), vaccinia virus strain Copenhagen and myxoma strain Lausanne) in three different media: DMEM 10%, DMEM 2% and serum-free medium VP-SFM. VP-SFM is a serum-free, ultra-low protein medium containing no proteins or peptides of human or animal origin designed to support the replication of viruses and the production of recombinant proteins and monoclonal antibodies. Our results show that high titre poxvirus stocks can be prepared in VP-SFM equivalent to that prepared in serum containing medium.     

The time-dependent transport of chromium in adult rats from the bloodstream to the urine

While chromium was proposed to be an essential trace element over 40 years ago and if essential should possess a specific transport and distribution mechanism, the details of its transport from the bloodstream to the urine have not been elucidated. However, chromium is known to be maintained in the bloodstream bound to transferrin and to be excreted in the urine bound to the oligopeptide chromodulin or a similar chromodulin-like species. Injection of ⁵¹Cr-labeled transferrin into the bloodstream resulted in a rapid and insulin-sensitive movement of chromium into the tissues as Cr transferrin; greater than 50% of the Cr is transported to the tissues within 30 min. Tissue levels of Cr are maximal 30 min after injection; decreases in tissue Cr with time are mirrored by increases in urine Cr. Approximately 50% of the ⁵¹Cr appears in the urine within 360 min of injection in the absence of added insulin; insulin treatment concurrent with injection of ⁵¹Cr-labeled transferrin results in approximately 80% of the label appearing in the urine within 180 min. The removal of ⁵¹Cr from the blood is faster than the appearance of ⁵¹Cr in the urine; the lag in time indicates that the Cr transferrin in the blood and Cr in the urine are not in direct equilibrium and that intermediates in the transport of Cr must be involved. This establishes a clear pathway of transport of Cr starting from transport by transferrin from the bloodstream into the tissues, followed by release and processing in the tissues to form chromodulin, excretion into the bloodstream, rapid clearance of chromodulin or a similar species into the urine, and ultimately excretion as this species. Insulin stimulates the processing of Cr in the tissues.     

Endonuclease-like activity of heme proteins

Heme proteins, metmyoglobin, methemoglobin, and metcytochrome c showed unusual affinity for double-stranded DNA. Calorimetric studies show that binding of methemoglobin to calf thymus DNA (CTDNA) is weakly endothermic, and the binding constant is 4.9+/-0.7x10(5) M(-1). The Soret absorption bands of the heme proteins remained unchanged, in the presence of excess CTDNA, but a new circular dichroic band appeared at 210 nm. Helix melting studies indicated that the protein-DNA mixture denatures at a lower temperature than the individual components. Thermograms obtained by differential scanning calorimetry of the mixture indicated two distinct transitions, which are comparable to the thermograms obtained for individual components, but there was a reduction in the excess heat capacity. Activation of heme proteins by hydrogen peroxide resulted in the formation of high valent Fe(IV) oxo intermediates, and CTDNA reacted rapidly under these conditions. The rate was first-order in DNA concentration, and this reactivity resulted in DNA strand cleavage. Upon activation with hydrogen peroxide, for example, the heme proteins converted the supercoiled pUC18 DNA into nicked circular and linear DNA. No reaction occurred in the absence of the heme protein, or hydrogen peroxide. These data clearly indicate a novel property of several heme proteins, and this is first report of the endonuclease-like activity of the heme proteins.     

Nonsymmetrical double logistic analysis of ambulatory blood pressure recordings.

We developed an asymmetric double logistic curve-fitting procedure for circadian analysis that can determine the rate of change in variables during the day-to-night separately from the night-to-day transition for use in animal studies. We now have applied this procedure to 24-h systolic (SAP) and diastolic arterial pressure (DAP) and heart rate ambulatory recordings from 302 patients. In 292 cases, all parameters showed a pattern of higher day and lower night values. In men there was a similar rate of transition between day and night or from night to day for both SAP and DAP that lasted 3-4 h, indicating a symmetrical diurnal pattern. By contrast, women showed a faster rate of decrease in mean arterial pressure in the evening compared with men (P < 0.05) and therefore showed an asymmetric diurnal SAP pattern. For both men and women, there was a markedly greater rate of morning increase in heart rate compared with the rate of evening decrease (2.2- and 1.9-fold, respectively, P < 0.001). The logistic method provided a better fit than the square-wave or the cosinor method (P < 0.001) and more appropriately detected nondippers. We conclude that analysis of ambulatory recordings by a new logistic curve-fitting method reveals more rapid reductions in evening SAP in women than men but both have two- to threefold more rapid morning rates of tachycardia. The ability of the double logistic method to determine the diurnal blood pressure rates of change independently is key to determining new markers for cardiovascular risk.     

Shelter competition between resident male red swamp crayfish Procambarus clarkii (Girard) and conspecific intruders varying by sex and reproductive status

The shelter defense dynamics of reproductively active (Form I) male red swamp crayfish Procambarus clarkii (Girard) were investigated by staging serial intrusions by male, maternal or non-maternal female conspecifics after one day of residence. The male residents showed a direct contest advantage only against non-maternal females, and won a significantly higher proportion of the encounters against non-maternal females than against either male or maternal female intruders. However, there was no significant difference in success against male or maternal female intruders. Further experiments against male intruders showed that increasing male prior residence to either 2 or 4 days did not significantly improve the residents' proportion of successful encounters. A final experiment revealed extremely low shelter fidelity in male P. clarkii, the most likely reason why male shelter defense against conspecific males and maternal females is not successful. These results, combined with those of past research, suggest that non-maternal females, juveniles and recently molted conspecifics are most vulnerable to predation and cannibalism, since males and maternal females easily out-compete non-maternal females for shelter, and adults out-compete juveniles. These findings may have implications for P. clarkii aquaculture and general management.