Experiments with trap crops against African bollowrm, Heliothis armigera, in Ethiopia

In a 1 ha haricot bean (HB) (Phaseolus vulgaris L.) field strip-cropped with 2 rows of maize (MZ) (Zea mays L.) on either side and then at 25 m intervals, the number of African bollworm (ABW) (Heliothis armigera (Hubner) (Lepidoptera: Noctuidae)) eggs + larvae on MZ was higher than that on HB by a factor of nearly 18. In a replicated experiment where five trap crops were compared with HB, as a check, all of them contained significantly greater numbers of ABW eggs + larvae than the check. Among the crops tested, lupin (LP) (Lupinus termis Forsk.) and pigeon pea (Cajanus cajan (L.) Millsp.) followed by hyacinth bean (Dolichos lalab L.) contained the highest ABW egg + larval population while sunflower (Helianthus annuus L.) contained the lowest; MZ was intermediate. On the other hand, HB plots bordered with MZ suffered significantly lower percent pod damage by ABW than did the check. Although grain yield differences among treatments were not significant, MZ-bordered plots gave nearly 22% higher yield than the check during the heavy ABW infestation in 1982. These differences were less obvious during the 1983 season because of low ABW infestation. In hot pepper (Capsicum spp.) strip-cropped with lupin, egg + larval counts on the latter were greater by a factor of nearly four in 1981 and 18 in 1982. It is concluded that trap-cropping has a great potential in the integrated management of ABW.

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Résumé En 1981, dans un champ de haricot (Phaseolus vulgaris), des cultures pièges de maïs (Zea mays) ont été semées en rangs doubles tous les 25 m et de chaque côté du champ, soit un total de 5 rangs doubles. Le nombre d'H. armigera (oeufs + chenilles) a été près de 18 fois plus élevé sur maïs que sur haricot.En 1982 et 1983, l'attractivité de 5 cultures pièges: Dolichos lablab, Lupinus termis, Z. mays, Cajanus cajan et Helianthus annuus, a été comparée à celle du haricot. Toutes ces plantes portaient un nombre d'oeufs et de chenilles supérieur au témoin (P. vulgaris). L'ordre décroissant des contaminations était: L. termis, C. cajan, D. lablab, Z. mays et H. annuus. Les rangs de P. vulgaris bordés par des rangs de Z. mays étaient moins contaminés que les témoins. Bien que les différences de rendements en graines suivant les expériences n'aient pas été significatives, les parcelles bordées de maïs ont fourni une récolte supérieure de 22%, pendant l'année 1982, où la contamination par H. armigera a été forte. En 1983, où l'infestation a été faible, les différences étaient moins claires.En 1981 et 1982, 5 rangs de L. tremis à 25 m d'intervalle ont été utilisés comme pièges pour protéger le piment fort (Capsicum spp.). Les décomptes d'oeufs et de chenilles ont été respectivement près de 4 et 18 fois plus élevés.La conclusion est que les cultures pièges ont un grand avenir dans la lutte intégrée contre H. armigera.

     

Detection of hepatitis C virus RNA by reverse-transcriptase and polymerase chain reaction: clinical applications of quantitative analysis

Polymerase chain reaction (PCR) applications to diagnostics allowed the detection of viral nucleic acids in expected and unexpected clinical circumstances. This has raised some scepticism on the practical usefulness of PCR in the routine laboratory and emphasized the need for quantitative analysis. We addressed this question detecting HCV-RNA by a single step RT-PCR in serum samples from 50 patients with chronic non-A, non-B hepatitis included in clinical trials for recombinant alpha-interferon therapy. We obtained at least 5 serum specimens from each patient (baseline, during and after therapy samples) during an 18-month mean follow-up (range 12-45 months). RT-PCR was performed on total RNA extracted from 100 microl serum aliquots using primers for the highly conserved 5'NCR of HCV-RNA and 35 amplification cycles. PCR products were analyzed by agarose gel electrophoresis and Southern blot hybridization against a P(32)-oligonucleotide probe. Sensitivity was evaluated in separate experiments on tenfold dilutions of a reference Chimp serum containing 10(6) CID(50)/ml. The overall sensitivity of our assay ranged between 10(2) and 10(3) genome Eq./ml. We establish a semiquantitative score system to evaluate viremia levels: 2 = HCV-RNA levels >10(4) genome Eq./ml; 1 = levels between 10(3) and 10(4) g.Eq./ml; 0 = levels less than 10(2) g.Eq/ml. The reproducibility of this scoring system was confirmed testing repeatedly in duplicate end-point dilutions of positive serum samples. A statistically significant relation was observed between elevated HCV-RNA and ALT values (83.8%, chi-square 159.963 P < 0.001). Response to IFN therapy was significantly better in patients with lower baseline HCV-RNA levels. A time relation was found between flare-ups of serum HCV-RNA levels and ALT elevations higher than 3 x normal values viremia elevations coincident or occurring about 1 month earlier than ALT elevations. This finding suggests that immuno pathogenesis might be responsible of HCV-induced liver damage as in chronic hepatitis B where identical relations were observed between viremia and ALT serum levels. In conclusion, single-step HCV-RNA RT-PCR can be a specific and reproducible semiquantitative assay and provides useful diagnostic informations for therapeutic decision making and monitoring of HCV-infected patients.     

Pro-Leu-Ser/Thr-Pro is a consensus primary sequence for substrate protein phosphorylation. Characterization of the phosphorylation of c-myc and c-jun proteins by an epidermal growth factor receptor threonine 669 protein kinase.

A growth factor-stimulated (MAP2-related) protein kinase, ERT, that phosphorylates the epidermal growth factor receptor at Thr669 has been purified from KB human tumor cells by Northwood and co-workers (Northwood, I. C., Gonzalez, F. A., Wartmann, M., Raden, D. L., and Davis, R. J. (1991) J. Biol. Chem. 266, 15266-15276). The ERT protein kinase has a restricted substrate specificity, and the structural determinants employed for substrate recognition by this enzyme have not been defined. As an approach toward understanding the specificity of substrate phosphorylation, we have used an in vitro assay to identify additional substrates for the ERT protein kinase. In this report we describe two novel substrates: (a) the human c-myc protein at Ser62 and (b) the rat c-jun protein at Ser246. Alignment of the primary sequences surrounding the phosphorylation sites located within the epidermal growth factor receptor (Thr669), Myc (Ser62), and Jun (Ser246) demonstrated a marked similarity. The observed consensus sequence was Pro-Leu-Ser/Thr-Pro. We propose that this sequence forms part of a substrate structure that is recognized by the ERT protein kinase.     

New advances and future directions in plant polyspermy

Plants have evolved a battery of mechanisms that potentially act as polyspermy barriers. Supernumerary sperm fusion to one egg cell has consequently long remained a hypothetical concept. The recent discovery that polyspermy in flowering plants is not lethal but generates viable triploid plants is a game changer affecting the field of developmental biology, evolution, and plant breeding. The establishment of protocols to artificially induce polyspermy together with the development of a high‐throughput assay to identify and trace polyspermic events in planta now provide powerful tools to unravel mechanisms of polyspermy regulation. These achievements are likely to open new avenues for animal polyspermy research as well, where forward genetic approaches are hampered by the fatal outcome of supernumerary sperm fusion.     

Serum levels of anti-heat shock protein 27 antibodies in patients with chronic liver disease

Heat shock protein 27 (HSP27), an intracellular molecular chaperone, is involved in the pathogenesis of cancer by promoting both tumor cell proliferation and resistance to therapy. HSP27 is also present in the circulation and circulating HSP27 (sHSP27) can elicit an autoimmune response with production of antibodies. Levels of sHSP27 are enhanced in patients with hepatocellular carcinoma (HCC); it is, however, unknown whether changes in HSP27 antibody levels occur in patients with HCC and can be exploited as a circulating biomarker of HCC. Our aim was to assess the potential association between newly diagnosed HCC and serum anti-HSP27 antibody levels. In this cross-sectional study, anti-HSP27 antibody levels were measured in serum samples from 71 HCC patients, 80 subjects with chronic liver disease, and 38 control subjects by immunoenzymatic assay. Anti-HSP27 antibody levels did not differ significantly among groups. However, in patients with chronic active hepatitis/cirrhosis, anti-HSP27 levels were significantly higher in subjects with a positive history of alcoholism (p = 0.03). Our data do not support the hypothesis that anti-HSP27 antibody levels may help identify patients with HCC among subjects with chronic liver disease. However, our finding that alcohol-related liver disease is associated with higher anti-HSP27 levels is novel and deserves further investigations.     

Exosomal and Non-Exosomal Transport of Extra-Cellular microRNAs in Follicular Fluid: Implications for Bovine Oocyte Developmental Competence

Cell-cell communication within the follicle involves many signaling molecules, and this process may be mediated by secretion and uptake of exosomes that contain several bioactive molecules including extra-cellular miRNAs. Follicular fluid and cells from individual follicles of cattle were grouped based on Brilliant Cresyl Blue (BCB) staining of the corresponding oocytes. Both Exoquick precipitation and differential ultracentrifugation were used to separate the exosome and non-exosomal fraction of follicular fluid. Following miRNA isolation from both fractions, the human miRCURY LNA™ Universal RT miRNA PCR array system was used to profile miRNA expression. This analysis found that miRNAs were present in both exosomal and non-exosomal fraction of bovine follicular fluid. We found 25 miRNAs differentially expressed (16 up and 9 down) in exosomes and 30 miRNAs differentially expressed (21 up and 9 down) in non-exosomal fraction of follicular fluid in comparison of BCB- versus BCB+ oocyte groups. Expression of selected miRNAs was detected in theca, granulosa and cumulus oocyte complex. To further explore the potential roles of these follicular fluid derived extra-cellular miRNAs, the potential target genes were predicted, and functional annotation and pathway analysis revealed most of these pathways are known regulators of follicular development and oocyte growth. In order to validate exosome mediated cell-cell communication within follicular microenvironment, we demonstrated uptake of exosomes and resulting increase of endogenous miRNA level and subsequent alteration of mRNA levels in follicular cells in vitro. This study demonstrates for the first time, the presence of exosome or non-exosome mediated transfer of miRNA in the bovine follicular fluid, and oocyte growth dependent variation in extra-cellular miRNA signatures in the follicular environment.     

Irreversible prey diapause as an optimal strategy of a physiologically extended Lotka–Volterra model

We propose an optimal control framework to describe intra-seasonal predator–prey interactions, which are characterized by a continuous-time dynamical model comprising predator and prey density, as well as the energy budget of the prey over the length of a season. The model includes a time-dependent decision variable for the prey, representing the portion of the prey population in time that is active, as opposed to diapausing (a state of physiological rest). The predator follows autonomous dynamics and accordingly it remains active during the season. The proposed model is a generalization of the classical Lotka–Volterra predator–prey model towards non-autonomous dynamics that furthermore includes the effect of an energy variable. The model has been inspired by a specific biological system of predatory mites (Acari: Phytoseiidae) and prey mites (so-called fruit-tree red spider mites) (Acari: Tetranychidae) that feed on leaves of apple trees—its parameters have been instantiated based on laboratory and field studies. The goal of the work is to understand the decisions of the prey mites to enter diapause (a state of physiological rest) given the dynamics of the predatory mites: this is achieved by solving an optimization problem hinging on the maximization of the prey population contribution to the next season. The main features of the optimal strategy for the prey are shown to be that (1) once in diapause, the prey does not become active again within the same season and hence diapause is an irreversible process; (2) for the vast majority of parameter space, the portion of prey individuals entering diapause within the season does not decrease in time; (3) with an increased number of predators, the optimal population strategy for the prey is to start diapause earlier and to enter diapause more gradually. This optimal population strategy will be studied for its ESS properties in a sequel to the work presented in this article.     

Melanoma central nervous system metastases: An update to approaches,challenges, and opportunities

In February 2018, the Melanoma Research Foundation and the Moffitt Cancer Center hosted the Second Summit on Melanoma Central Nervous System (CNS) Metastases in Tampa, Florida. In this white paper, we outline the current status of basic science, translational, and clinical research into melanoma brain metastasis development and therapeutic management. We further outline the important challenges that remain for the field and the critical barriers that need to be overcome for continued progress to be made in this clinically difficult area.