Efficacy and nontarget effects of reduced-risk insecticides on Aphis glycines (Hemiptera: Aphididae) and its biological control agent Harmonia axyridis (Coleoptera: Coccinellidae)

The efficacy of three reduced-risk insecticides (pyrethrins, insecticidal soap, and narrow-range mineral oil) was determined for nymphs and adults of the soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), an exotic pest of North American soybean, Glycine max (L.) Merr. These insecticides also were evaluated for nontarget effects on one of the aphid's key biological control agents, multicolored Asian lady beetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), including first and third instars, pupae, and adults. A Potter Spray Tower was used to conduct direct spray laboratory bioassays. Results indicated that although pyrethrins and narrow-range mineral oil caused 100% mortality to A. glycines nymphs and adults at 72 h posttreatment, insecticidal soap caused equivalent mortality to only the nymphs during the same time period. However, A. glycines adult mortality due to the insecticidal soap (83.3%) was significantly greater than the control. Pyrethrins were highly toxic to first instars of H. axyridis (98% mortality), but they had no effect on third instars, pupae, or adults. Mineral oil and insecticidal soap were moderately lethal to first (48.9 and 40% mortality, respectively) and third (31.9 and 38.8% mortality, respectively) instars of H. axyridis, but they had no effect on pupae and adults. Our results suggest that pyrethrins, insecticidal soap, and narrow-range mineral oil may prove useful for soybean aphid management in organic soybean due to efficacy against the aphid with differential nontarget effects on select stages of H. axyridis. Additional studies will be necessary to elucidate the efficacy of these insecticides under field conditions.     

First multi-locus sequence typing scheme for Arcobacter spp.

Background  

Arcobacter spp. are a common contaminant of food and water, and some species, primarily A. butzleri and A. cryaerophilus, have been isolated increasingly from human diarrheal stool samples. Here, we describe the first Arcobacter multilocus sequence typing (MLST) method for A. butzleri, A. cryaerophilus, A. skirrowii, A. cibarius and A. thereius.     

NadN and e (P4) are essential for utilization of NAD and nicotinamide mononucleotide but not nicotinamide riboside in Haemophilus influenzae

Haemophilus influenzae has an absolute requirement for NAD (factor V) because it lacks almost all the biosynthetic enzymes necessary for the de novo synthesis of that cofactor. Factor V can be provided as either nicotinamide adenosine dinucleotide (NAD), nicotinamide mononucleotide (NMN), or nicotinamide riboside (NR) in vitro, but little is known about the source or the mechanism of uptake of these substrates in vivo. As shown by us earlier, at least two gene products are involved in the uptake of NAD, the outer membrane lipoprotein e (P4), which has phosphatase activity and is encoded by hel, and a periplasmic NAD nucleotidase, encoded by nadN. It has also been observed that the latter gene product is essential for H. influenzae growth on media supplemented with NAD. In this report, we describe the functions and substrates of these two proteins as they act together in an NAD utilization pathway. Data are provided which indicate that NadN harbors not only NAD pyrophosphatase but also NMN 5'-nucleotidase activity. The e (P4) protein is also shown to have NMN 5'-nucleotidase activity, recognizing NMN as a substrate and releasing NR as its product. Insertion mutants of nadN or deletion and site-directed mutants of hel had attenuated growth and a reduced uptake phenotype when NMN served as substrate. A hel and nadN double mutant was only able to grow in the presence of NR, whereas no uptake of NMN was observed.     

Flat Feet,Happy Feet? Comparison of the Dynamic Plantar Pressure Distribution and Static Medial Foot Geometry between Malawian and Dutch Adults

In contrast to western countries, foot complaints are rare in Africa. This is remarkable, as many African adults walk many hours each day, often barefoot or with worn-out shoes. The reason why Africans can withstand such loading without developing foot complaints might be related to the way the foot is loaded. Therefore, static foot geometry and dynamic plantar pressure distribution of 77 adults from Malawi were compared to 77 adults from the Netherlands. None of the subjects had a history of foot complaints. The plantar pressure pattern as well as the Arch Index (AI) and the trajectory of the center of pressure during the stance phase were calculated and compared between both groups. Standardized pictures were taken from the feet to assess the height of the Medial Longitudinal Arch (MLA). We found that Malawian adults: (1) loaded the midfoot for a longer and the forefoot for a shorter period during roll off, (2) had significantly lower plantar pressures under the heel and a part of the forefoot, and (3) had a larger AI and a lower MLA compared to the Dutch. These findings demonstrate that differences in static foot geometry, foot loading, and roll off technique exist between the two groups. The advantage of the foot loading pattern as shown by the Malawian group is that the plantar pressure is distributed more equally over the foot. This might prevent foot complaints.     

NADP and NAD utilization in Haemophilus influenzae

Exogenous NAD utilization or pyridine nucleotide cycle metabolism is used by many bacteria to maintain NAD turnover and to limit energy-dependent de novo NAD synthesis. The genus Haemophilus includes several important pathogenic bacterial species that require NAD as an essential growth factor. The molecular mechanisms of NAD uptake and processing are understood only in part for Haemophilus. In this report, we present data showing that the outer membrane lipoprotein e(P4), encoded by the hel gene, and an exported 5'-nucleotidase (HI0206), assigned as nadN, are necessary for NAD and NADP utilization. Lipoprotein e(P4) is characterized as an acid phosphatase that uses NADP as substrate. Its phosphatase activity is inhibited by compounds such as adenosine or NMN. The nadN gene product was characterized as an NAD-nucleotidase, responsible for the hydrolysis of NAD. H. influenzae hel and nadN mutants had defined growth deficiencies. For growth, the uptake and processing of the essential cofactors NADP and NAD required e(P4) and 5'-nucleotidase. In addition, adenosine was identified as a potent growth inhibitor of wild-type H. influenzae strains, when NADP was used as the sole source of nicotinamide-ribosyl.     

Escaping the nuclear confines: signal-dependent pre-mRNA splicing in anucleate platelets

Platelets are specialized hemostatic cells that circulate in the blood as anucleate cytoplasts. We report that platelets unexpectedly possess a functional spliceosome, a complex that processes pre-mRNAs in the nuclei of other cell types. Spliceosome components are present in the cytoplasm of human megakaryocytes and in proplatelets that extend from megakaryocytes. Primary human platelets also contain essential spliceosome factors including small nuclear RNAs, splicing proteins, and endogenous pre-mRNAs. In response to integrin engagement and surface receptor activation, platelets precisely excise introns from interleukin-1beta pre-mRNA, yielding a mature message that is translated into protein. Signal-dependent splicing is a novel function of platelets that demonstrates remarkable specialization in the regulatory repertoire of this anucleate cell. While this mechanism may be unique to platelets, it also suggests previously unrecognized diversity regarding the functional roles of the spliceosome in eukaryotic cells.     

Cooperation of p53 and polyoma virus middle T antigen in the transformation of primary rat embryo fibroblasts.

Cell transformation in vivo seems to be a multistep process. In in vitro studies certain combinations of two oncogenes, a cytoplasmic gene product together with a nuclear gene product, are sufficient to transform primary rodent cells. Polyoma virus large T antigen can immortalize and, in cooperation with polyoma virus middle T antigen, transform primary cells. On the other hand mutant mouse p53 can also immortalize and, in cooperation with an activated Ha-ras oncogene, transform primary cells. In the present study we analyzed whether mutant p53 can replace polyoma virus large T antigen in a cell transformation assay with polyoma virus middle T antigen. Transfection of mutant p53 alone resulted in a cell line which had retained the actin cable network, grew poorly in medium with low concentration of serum, and failed to grow in semisolid agar. Cotransfection of mutant p53 together with polyoma virus middle T led to cells which grew in medium containing low serum concentration, grew well in semisolid agar, and displayed an altered morphology with the tendency to overgrow the normal monolayer. By these criteria these cells were considered fully transformed. The rate of p53 synthesis was similar in both cell lines. However, only p53 from the transformed cell line turned out to be stable. Cells transformed by mutant p53 and polyoma virus middle T expressed nearly the same amount of the c-src-encoded pp60c-src protein as cells transformed by the same p53 and cotransfected activated Ha-ras oncogene. However, only the polyoma virus middle T/p53-transformed cells exhibited an elevated level of pp60c-src-specific tyrosine kinase activity. Thus, despite different mechanisms leading to cell transformation, mutant p53 can replace polyoma virus large T antigen and polyoma virus middle T can replace the activated Ha-ras oncogene in cell transformation.     

The relationship of aerobic capacity,anaerobic peak power and experience to performance in CrossFit exercise

CrossFit is becoming increasingly popular as a method to increase fitness and as a competitive sport in both the Unites States and Europe. However, little research on this mode of exercise has been performed to date. The purpose of the present investigation involving experienced CrossFit athletes and naïve healthy young men was to investigate the relationship of aerobic capacity and anaerobic power to performance in two representative CrossFit workouts: the first workout was 12 minutes in duration, and the second was based on the total time to complete the prescribed exercise. The participants were 32 healthy adult males, who were either naïve to CrossFit exercise or had competed in CrossFit competitions. Linear regression was undertaken to predict performance on the first workout (time) with age, group (naïve or CrossFit athlete), VO₂max and anaerobic power, which were all significant predictors (p < 0.05) in the model. The second workout (repetitions), when examined similarly using regression, only resulted in CrossFit experience as a significant predictor (p < 0.05). The results of the study suggest that a history of participation in CrossFit competition is a key component of performance in CrossFit workouts which are representative of those performed in CrossFit, and that, in at least one these workouts, aerobic capacity and anaerobic power are associated with success.