Variability in host plant resistance of Sorghum to Striga Hermonthica infestation in West Africa

Fourteen elite sorghum lines were evaluated for their resistance to Striga hermonthica at three locations in Nigeria and Mali. Results showed that many of the lines especially MALISOR 84-1, SAMSORG 41, 97-SB-F5DT-64 (Keninkédié) and the check SRN 39 remained resistant to Striga in all locations with low emerged Striga counts, while SAMSORG 14 had the highest Striga infestation in all locations. Considerable variation in reaction to Striga infestation was observed on Séguètana, 97-SB-F5DT-63 (Wasa), 97-SB-F5DT-65, CMDT 38, CMDT 39 and CMDT 45 which were susceptible to Striga at Samaru, Nigeria but were resistant to Striga at both locations in Mali. Based on low Striga resistance and high grain yield, lines MALISOR 84-1, SAMSORG 41, 97-SB-F5DT-64, 97-SB-F5DT-65, CMDT 39 and SAMSORT 14 have been nominated for wider evaluation across more West African countries.     

Complete lab-scale detoxification of groundwater containing 1,2-dichloroethane

The suspected carcinogenic solvent 1,2-dichloroethane (1,2-DCA) is the most abundant chlorinated C₂ groundwater pollutant on earth. However, an efficient reductive in situ detoxification technology for this compound is not known. Detoxification results of 1,2-DCA with the recently isolated anaerobic bacterium Desulfitobacterium dichloroeliminans strain DCA1 are presented. First, it was verified that strain DCA1 could compete for nutrients in the presence of fast-growing Enterococcus faecalis; the latter was observed in the enrichment culture from which strain DCA1 was isolated. Subsequently, lab-scale bioaugmentation of the strain to groundwater containing 40 mg 1,2-DCA/l indicated that the bacterium has strong metabolic activity under prevailing environmental conditions, converting the pollutant into ethene. During exponential growth, the maximum 1,2-DCA dechlorination rate exceeded 350 nmol chloride released per min per mg total bacterial protein. Growth and dechlorination within the community with autochthonous bacteria indicated a high competitive strength of strain DCA1. Interestingly this dechlorination process does not produce any toxic byproducts, such as vinyl chloride. Furthermore, complete groundwater detoxification happens within a short time-frame (days) and is robust in terms of bacterial competition, oxygen tolerance, high ionic strength, and pH range.     

Long-term effects of graduated compression stockings on cardiorespiratory performance

The use of graduated compression stockings (GCS) in sport has been increasing in the last years due to their potential positive effects for athletes. However, there is little evidence to support whether these types of garments actually improve cardiorespiratory performance. The aim of this study was to examine the cardiorespiratory responses of GCS during running after three weeks of regular use. Twenty recreational runners performed three tests on different days: test 1) – a 5-min maximal effort run in order to determine the participants’ maximal aerobic speed; and tests 2) and 3) – a fatigue running test of 30 minutes at 80% of their maximal aerobic speed with either GCS or PLACEBO stockings at random. Cardiorespiratory parameters (minute ventilation, heart rate, relative oxygen consumption, relative carbon dioxide production, ventilatory equivalents for oxygen and carbon dioxide, and oxygen pulse) were measured. Before each test in the laboratory, the participants trained with the randomly assigned stockings (GCS or PLACEBO) for three weeks. No significant differences between GCS and PLACEBO were found in any of the cardiorespiratory parameters. In conclusion, the present study provides evidence that running with GCS for three weeks does not influence cardiorespiratory parameters in recreational runners.     

Stereoselective Microbial Dehalorespiration with Vicinal Dichlorinated Alkanes

The suspected carcinogen 1,2-dichloroethane (1,2-DCA) is the most abundant chlorinated C₂ groundwater pollutant on earth. However, a reductive in situ detoxification technology for this compound does not exist. Although anaerobic dehalorespiring bacteria are known to catalyze several dechlorination steps in the reductive-degradation pathway of chlorinated ethenes and ethanes, no appropriate isolates that selectively and metabolically convert them into completely dechlorinated end products in defined growth media have been reported. Here we report on the isolation of Desulfitobacterium dichloroeliminans strain DCA1, a nutritionally defined anaerobic dehalorespiring bacterium that selectively converts 1,2-dichloroethane and all possible vicinal dichloropropanes and -butanes into completely dechlorinated end products. Menaquinone was identified as an essential cofactor for growth of strain DCA1 in pure culture. Strain DCA1 converts chiral chlorosubstrates, revealing the presence of a stereoselective dehalogenase that exclusively catalyzes an energy-conserving anti mechanistic dichloroelimination. Unlike any known dehalorespiring isolate, strain DCA1 does not carry out reductive hydrogenolysis reactions but rather exclusively dichloroeliminates its substrates. This unique dehalorespiratory biochemistry has shown promising application possibilities for bioremediation purposes and fine-chemical synthesis.     

Overexpression,purification, and structural analysis of the hydrophobic E5 protein from human papillomavirus type 16

The E5 proteins of human papillomavirus (HPV) are highly hydrophobic transmembrane proteins that display weak transforming activity. The HPV E5 proteins are localized largely to intracellular membranes, such as the Golgi apparatus and endoplasmic reticulum, but also appear in the plasma membrane. Infection with HPV16 is the cause of over 90% of human cervical cancers. HPV E5 is known to interact with growth factor receptors and gap junction proteins and is believed to play a role during the initiation of neoplasia. The structure of HPV E5 and the mechanism of its interactions with growth factor receptors remain largely unknown. In the present studies, the E5 protein of HPV16 was cloned into the pBAD/TOPO vector fused to an N-terminal thioredoxin leader and a C-terminal His-tag, and expressed in Escherichia coli. The identity of the protein was confirmed by immunoblotting using antibodies against a V5-epitope tag engineered into the protein. Due to formation of high molecular mass superaggregates of the protein, two chromatography steps were employed for its purification: (1) gel filtration chromatography to separate the superaggregated protein from other soluble proteins and (2) Ni-chelate affinity chromatography in the presence of detergent. The superaggregates of the E5-fusion protein were broken down to monomers and various oligomers by sonication in the presence of 0.2% SDS. The purified E5-fusion protein was then reconstituted into lipid vesicles and initial structural analysis of the protein was performed using circular dichroism spectroscopy.