An assessment of the effectiveness of a large,national-scale invasive alien plant control strategy in South Africa

This paper presents an assessment of a large, national-scale alien plant control program that has operated in South Africa for 15 years. We reviewed data from three national-level estimates of the extent of invasion, records of the costs and spatial extent of invasive species control operations, assessments of the effectiveness of biological control, and smaller-scale studies. The 19 most important invasive taxa, mainly trees, in terrestrial biomes were identified. The effectiveness of control efforts on the extent of invasion of these taxa was assessed. Control costs over 15 years amounted to 3.2 billion rands (US$457 million), more than half of which was spent on 10 taxa, the most prominent being in the genera Acacia, Prosopis, Pinus and Eucalyptus. Despite substantial spending, control operations were in many cases applied to a relatively small portion of the estimated invaded area, and invasions appear to have increased, and remain a serious threat, in many biomes. Our findings suggest that South Africa’s national-scale strategy to clear invasive alien plants should be substantially modified if impacts are to be effectively mitigated. Rather than attempting to control all species, and to operate in all areas, a more focused approach is called for. This would include prioritising both the species and the areas, and setting goals and monitoring the degree to which they are achieved, within a framework of adaptive management. A greater portion of funding should also be directed towards biological control, where successes have been most notable.     

Evaluation of Nebraska Waxy Sorghum Hybrids for Ethanol Production

To evaluate the ethanol production performance of waxy sorghum hybrids and the effects of location and harvest year on ethanol yield, samples of four waxy sorghum hybrids collected from two Nebraska locations (Mead and Lincoln) in both 2009 and 2010 were tested for ethanol production in a dry‐grind process. No significant difference (P = 0.216) in starch contents was observed among the four hybrids, but starch contents of the hybrids were significantly affected by growth location (P = 0.0001) and harvest year (P = 0.0258). Location, hybrid, and harvest year all had significant effects on ethanol fermentation efficiency in the dry‐grind process. Lincoln sorghum samples showed higher (P = 0.022) ethanol fermentation efficiency (90.4%) than did Mead sorghum samples (90.0%). Sorghums harvested in 2010 had higher (P < 0.001) ethanol fermentation efficiency (91.1%) than those harvested in 2009 (89.3%). The 2009 sorghum flours had more amylose‐lipid complexes than the 2010 samples did, and amylose‐lipid complexes as previously reported had adverse effects on ethanol fermentation. Residual starch contents in distillers dried grains with solubles (DDGS) were significantly affected by hybrid and harvest year (P < 0.0001), but we observed no difference in protein content in DDGS from the four hybrids.     

Occurrence of zearalenone-4-beta-D-glucopyranoside in wheat

An LC-MS method was developed for the analysis of zearalenone-4-beta-D-glucopyranoside and zearalenone in wheat (Triticum aestivum). The limit of determination for zearalenone-4-beta-D-glucopyranoside and zearalenone was 10 microg/kg. The recovery rates were calculated to be 69% and 89% at a concentration of 100 microg/kg for zearalenone-4-beta-D-glucopyranoside and zearalenone, respectively. Twenty-four Bavarian wheat samples from a 1999 harvest were analyzed. Zearalenone was present in 22 of 24 field samples, the levels ranged from 11 to 860 microg/kg. Zearalenone-4-beta-D-glucopyranoside was found in 10 of the zearalenone positive samples (42%) at levels ranging from 17 to 104 microg/kg. The amounts of zearalenone-4-beta-D-glucopyranoside were correlated to those of zearalenone (r2 = 0.86, b = 0.10). After gastrointestinal hydrolyzation, zearalenone-4-beta-glucopyranoside might be implicated in the development of a zearalenone-syndrome. Therefore, more attention should be focused on conjugated mycotoxins in food and feed.     

A molecular epidemiologic investigation of Salmonella from a meat source to the feces of captive cheetah (Acinonyx jubatus).

Low cheetah (Acinonyx jubatus) birth rates were observed for a long time in a captive breeding facility in which Salmonella, which was possibly present in contaminated beef, was isolated from still-born lion (Panthera leo) cubs. Salmonella, including 14 isolates of Salmonella serovar typhimurium and 19 isolates of Salmonella serovar muenchen, was subsequently isolated 47 times from 378 meat samples at the facility during a 13-mo period. Salmonella, including 26 isolates of S. serovar typhimurium, 10 of S. serovar muenchen, and 11 other serovars, also was isolated 54 times from 119 fecal samples. Only three plasmid profiles were identified in 59 S. typhimurium isolates from both meat and fecal samples. Although random-amplified polymorphic DNA fingerprinting using different primers in the polymerase chain reaction was able to distinguish between S. typhimurium and S. muenchen and to demonstrate similar chromosomal DNA fingerprints in some of the isolates from meat and feces, the results were not consistent enough to prove that the Salmonella in the feces originated from contaminated meat. However, the predominance of only two serovars in the meat fed to carnivores and in the feces of these animals suggests that the meat was the source of the Salmonella organisms in the feces.     

Beliefs of South Africans regarding food and cardiovascular health

OBJECTIVES: To investigate the beliefs of South African metropolitan adults regarding the importance of influencing cardiovascular health by eating certain food types, and to compare these beliefs between different race, living standards, age and gender groups. DESIGN: Randomised cross-sectional study. Trained fieldworkers administered questionnaires by conducting face-to-face interviews with consumers. SUBJECTS: Two thousand South Africans (16 years and older) were randomly selected from metropolitan areas in South Africa. The data were weighted to be representative of the total South African metropolitan population (N = 10 695 000) based on gender, age and race distribution. RESULTS: The majority (94 %) of the population indicated that it is important to influence cardiovascular risk-related health issues by eating certain food types, especially the higher LSM (Living Standard Measure) groups within the different race groups. Weight loss was considered the least important (61 % indicated that it is important) compared with cholesterol lowering (80 %), blood pressure (89 %), diabetes (86 %) and healthy blood vessels (89 %). In the higher LSM groups (7-10) higher proportions of respondents agreed than in the lower LSM groups (2 and 3). No differences were seen in responses between different gender, race and age groups.Conclusions and recommendationsThis study shows that the metropolitan South African adult population considers the influence on cardiovascular health by eating certain food types to be important. However, modifying weight loss by eating certain food types was considered less important.     

Extensive mast cell degranulation in bovine respiratory syncytial virus-associated paroxystic respiratory distress syndrome

Bovine respiratory syncytial virus (BRSV) infection is an important cause of outbreaks of respiratory disease among calves. This virus commonly induces mild to severe respiratory signs but, in a substantial proportion of cases, is also reported to be associated with paroxystic respiratory distress syndrome (PRDS). The pathogenesis of this 'malignant' clinical form has not been fully elucidated. The present study aimed at determining whether mast cell (MC) degranulation plays a role in the physiopathologic cascade leading to the PRDS. Paired serum samples were taken in herds during outbreaks of severe respiratory diseases (acute sera) and 3 weeks after (convalescent sera). Based on seroconversion to BRSV and clinical picture, 67 pairs of sera were selected from calves with a BRSV-associated PRDS for circulating MC tryptase determination. A MC metachromatic score was measured in post-mortem lungs from animals died from a BRSV-associated PRDS (principals) and compared with reference scores obtained from healthy lungs (controls). Levels of tryptase were significantly higher in acute sera (26.6 +/- 12.4 microg/l) compared to convalescent sera (8.4 +/- 7.8 microg/l; P<0.001). Metachromatic scores yielded significantly different results between controls and principals (P<0.01), demonstrating a significant disappearance of metachromatic granules from lung MCs in principals. Taken together, these data demonstrate the presence of an extensive MC degranulation in BRSV-associated PRDS.     

Mutants of Rhizobium japonicum with Increased Hydrogenase Activity

Some strains of Rhizobium japonicum can use hydrogen as an energy source for growth under microaerophilic conditions. Mutant strains have been selected that use hydrogen in the presence of high partial pressures of oxygen. The mutants contain more hydrogenase than the parent strain, both as free-living cells and as bacteroids in nitrogen-fixing soybean root nodules.     

Probing the ultimate limits of plasmonic enhancement

Metals support surface plasmons at optical wavelengths and have the ability to localize light to subwavelength regions. The field enhancements that occur in these regions set the ultimate limitations on a wide range of nonlinear and quantum optical phenomena. We found that the dominant limiting factor is not the resistive loss of the metal, but rather the intrinsic nonlocality of its dielectric response. A semiclassical model of the electronic response of a metal places strict bounds on the ultimate field enhancement. To demonstrate the accuracy of this model, we studied optical scattering from gold nanoparticles spaced a few angstroms from a gold film. The bounds derived from the models and experiments impose limitations on all nanophotonic systems.