Progeny Production Research Articles

Seasonal and Floor Variations of Indoor Radon Concentration

Radon is a naturally occurring, colourless and odourless radioactive gas, with a halflife of 3.8 days. Dangerous is not radon itself, but its progeny (daughter) products. The radon decay products irradiating of the lung. There is a strong correlation between radon exposure and lung cancer. The indoor radon concentrations in residential buildings are monitored. The study is performed in eight storied blocks of flats and also in family houses. The contributed deals with the radon concentration depending on a year season and floor level. Radon concentrations are varying with the characteristics of the building and its ventilation. Statistical analysis of the results shows that the probability that a weekly measurement represents the yearly radon concentration is significantly higher (twice) in winter and in summer than in summer and autumn. The maximum values of radon concentration is obtained in the first and second-floor rooms might be due to the contribution of radon emanation from the soil, entering into the living spaces from the ground.

Fitness consequences of delayed mating on reproductive performance of Chilo partellus (Swinhoe).

We investigated the effects of mating among different-aged males and females on reproductive physiology, progeny production, and longevity of Chilo partellus (Swinhoe) adults under laboratory conditions. Present studies involved virgin males (M) and females (F) of three different ages namely, on the day of emergence (1D), next day (2D), and further next day (3D), thus comprising of a total of nine mating treatments (1DM × 1DF, 1DM × 2DF, 1DM × 3DF, 2DM × 1DF, 2DM × 2DF, 2DM × 3DF, 3DM × 1DF, 3DM × 2DF, and 3DM × 3DF). The observations were recorded on fecundity, fertility, hatchability, and longevity of male and female adults. We found that mating among old aged males and females significantly reduce fecundity, fertility, and egg hatchability. Further, the fecundity, fertility, and egg hatching were significantly higher when newly emerged females mated with either of the ages of males as compared with other mating treatments. Conversely, the 3-day-old females, when mated with either of the ages of males, laid more numbers of unfertilized eggs, thus reduction in egg hatchability. Mating among newly emerged adults significantly reduced the longevity of male and female adults. Kaplan-Meier estimation showed that none of the adults across mating treatments survived more than 6 days. The recovery of spermatophores from the reproductive tract of females from 3DM × 1DF were significantly higher than other mating treatments. However, no association was found between spermatophore recovery and longevity of male and female adults. Findings of present studies will help to devise appropriate techniques to disrupt mating and suppress C. partellus population under field conditions.

The feline calicivirus leader of the capsid protein causes survivin and XIAP downregulation and apoptosis

Calicivirus infection causes intrinsic apoptosis, leading to viral propagation in the host. During murine norovirus infection, a reduction in the anti-apoptotic protein survivin has been documented. Here we report that in feline calicivirus infection, a downregulation of the anti-apoptotic proteins survivin and XIAP occur, which correlates with the translocation of the pro-apoptotic protein Smac/DIABLO from the mitochondria to the cytoplasm and the activation of caspase-3. Inhibition of survivin degradation by lactacystin treatment caused a delay in apoptosis progression, reducing virus release, without affecting virus production. However, the overexpression of survivin caused a negative effect in viral progeny production. Overexpression of the leader of the capsid protein (LC), but not of the protease-polymerase NS6/7, results in the downregulation of survivin and XIAP, caspase activation and mitochondrial damage. These results indicate that LC is responsible for the induction of apoptosis in transfected cells and most probably in FCV infection.

Cryoprotectant toxicity in Caenorhabditis elegans

We have looked at the effects of the cryoprotectant M22 upon viability in the model organism C. elegans. M22 is a well-known vitrification solution which has been successfully used in the laboratory to preserve organs destined for transplantation. M22 reduces survival of C. elegans in a concentration-dependent manner. M22 at concentrations of 10% (v/v) or higher inhibits progeny production and development. A few mutants in the ILS (insulin-like signaling) pathway of C. elegans are more resistant to the toxic effect of M22 compared to wild-type worms. Afatinib, an anti-cancer drug, protects against M22 toxicity. Afatinib by itself does not increase longevity.

The NAD+ Salvage Pathway Potently Stimulates Hematopoiesis through Increased Mitochondrial Clearance and Asymmetric Division

During the last 50 years, with over a million transplants, hematopoietic stem cell (HSC) transplantation has been the first and most extensively exploited stem cell therapy and the only curative regime for most acute leukemias. Nevertheless, the success of HSC transplantation and all other intensive ablative chemotherapy regimes is still overshadowed by a procedure-associated mortality of ~25%, due to both graft versus host disease and to the infectious complications associated with the severe leucopenia following bone marrow (BM) ablation, even in spite of standard support with HSC-stimulating factor G-CSF. It has been recently shown that increased oxidative phosphorylation, as reflected by increased mitochondrial activity, together with impairment of the mitochondrial stress response can severely compromise HSC regeneration.Here we show that the NAD+-boosting agents Nicotinamide Riboside (NR) and Nicotinamide MonoNucleotide (NMN) reduce mitochondrial activity within HSCs through increased mitochondrial clearance via autophagy and possibly the Unfolded Protein Response mitochondria (UPRmt), leading to increased asymmetric HSC divisions as measured by asymmetric mitochondrial distribution in single cell pair-daughter analysis. This process was abrogated in Nrk1-/-;Nrk2-/- double knock out mice, which cannot incorporate NR into the NAD+ salvage pathway. Contrary to controls, purified murine HSC underwent self-renewal in minimal culture conditions in presence of NR, and human CD34+ hematopoietic progenitors (hCD34+) cultured in vitro in presence of NR could repopulated NSG mice in primary and secondary transplant recipients.In vivo, NR dietary supplementation resulted in a significantly enlarged pool of progenitors, without concurrent HSC exhaustion, improved survival by 80%, and accelerated blood recovery after murine lethal irradiation and limiting-HSC transplantation. In human xenotransplanted immune-deficient NSG mice, NR increased the production of human leucocyte progeny from hCD34+ progenitors. Our work demonstrates for the first time a positive effect of NAD+ boosting strategies on the most primitive blood stem cells, establishes a novel link between mitochondrial stress, mitophagy and stem cell fate decision, and unveils the potential of NR in vivo supplementation to improve recovery of patients suffering from hematological failure including post-chemo/radiotherapy. DisclosuresNo relevant conflicts of interest to declare.

Genetic variance for flowering time conferring E2 gene in photoperiod-insensitive early-maturing soybean accessions and topological distribution in Korea peninsula

Soybean [Glycine max (L.) Merr.] is one of the major legume crops for human and livestock, and the double cropping system with soybean have been widely applied to increase arable land utilization rate. To employ the soybean for multiple cropping system, cultivars, which are photoperiod insensitive and early maturing, are required. The region-specific crop adaptation could be achieved by the successful flowering followed by progeny production, and it is important to understand the mechanisms underlying the transition from the vegetative to reproductive stage. In soybean, 10 genes/QTLs conferring flowering time were identified, and four genes, E1, E2, E3, and E4, are mainly involved in geographic adaptation of soybean. Here, to develop the photoperiod-insensitive early-maturing soybean varieties, QTL analysis was conducted using RILs from the crosses between photoperiod-insensitive early-maturing soybean cultivar, Keunol, and late maturity soybean cultivar, Sinpaldal. Furthermore, to identify the topological distribution within Korea peninsula, SNPs in exon region of 40 soybean varieties were investigated by sequencing of the exon region in E2 and comparing to their origin information. The results showed that early flowering is mainly controlled by the E2 in five different environments, and there are three nonsynonymous SNPs in E2. Two of them, SNPs in exon 2 and 10, produce the premature stop codon. The first SNP in exon 2 was strongly linked to topological distribution, which is mainly restricted to southern area of Korea peninsula. This result could provide the useful information to develop photo-insensitive early-maturing soybean cultivar, which could be employed in various cropping system.

Regulation of Epstein-Barr Virus Life Cycle and Cell Proliferation by Histone H3K27 Methyltransferase EZH2 in Akata Cells.

Epigenetic modifications play a pivotal role in the expression of the genes of Epstein-Barr virus (EBV). We found that de novo EBV infection of primary B cells caused moderate induction of enhancer of zeste homolog 2 (EZH2), the major histone H3 lysine 27 (K27) methyltransferase. To investigate the role of EZH2, we knocked out the EZH2 gene in EBV-negative Akata cells by the CRISPR/Cas9 system and infected the cells with EBV, followed by selection of EBV-positive cells. During the latent state, growth of EZH2-knockout (KO) cells was significantly slower after infection compared to wild-type controls, despite similar levels of viral gene expression between cell lines. After induction of the lytic cycle by anti-IgG, KO of EZH2 caused notable induction of expression of both latent and lytic viral genes, as well as increases in both viral DNA replication and progeny production. These results demonstrate that EZH2 is crucial for the intricate epigenetic regulation of not only lytic but also latent gene expression in Akata cells.IMPORTANCE The life cycle of EBV is regulated by epigenetic modifications, such as CpG methylation and histone modifications. Here, we found that the expression of EZH2, which encodes a histone H3K27 methyltransferase, was induced by EBV infection; therefore, we generated EZH2-KO cells to investigate the role of EZH2 in EBV-infected Akata B cells. Disruption of EZH2 resulted in increased expression of EBV genes during the lytic phase and, therefore, efficient viral replication and progeny production. Our results shed light on the mechanisms underlying reactivation from an epigenetic point of view and further suggest a role for EZH2 as a form of innate immunity that restricts viral replication in infected cells.

The novel HBx mutation F30V correlates with hepatocellular carcinoma in vivo, reduces hepatitis B virus replicative efficiency and enhances anti-apoptotic activity of HBx N terminus in vitro

ObjectiveWe aimed to investigate HBx genetic elements correlated with hepatitis B virus (HBV) -related hepatocellular carcinoma (HCC) and their impact on (a) HBV replicative efficiency, (b) HBx binding to circular covalently closed DNA (cccDNA), (c) apoptosis and cell-cycle progression, and (d) HBx structural stability. MethodsThis study included 123 individuals chronically infected with HBV: 27 with HCC (77.9% (21/27) genotype D; 22.1% (6/27) genotype A) and 96 without HCC (75% (72/96) genotype D; 25.0% (24/96) genotype A). HepG2 cells were transfected by wild-type or mutated linear HBV genome to assess pre-genomic RNA (pgRNA) and core-associated HBV-DNA levels, HBx-binding onto cccDNA by chromatin immunoprecipitation-based quantitative assay, and rate of apoptosis and cell-cycle progression by cytofluorimetry. ResultsF30V was the only HBx mutation correlated with HCC (18.5% (5/27) in HCC patients versus 1.0% (1/96) in non-HCC patients, p 0.002); a result confirmed by multivariate analysis. In vitro, F30V determined a 40% and 60% reduction in pgRNA and core-associated HBV-DNA compared with wild-type (p <0.05), in parallel with a significant decrease of HBx binding to cccDNA and decreased HBx stability. F30V also decreased the percentage of apoptotic cells compared with wild-type (14.8 ± 6.8% versus 19.1 ± 10.1%, p <0.01, without affecting cell-cycle progression) and increased the probability of HBx-Ser-31 being phosphorylated by PI3K-Akt kinase (known to promote anti-apoptotic activity). ConclusionsF30V was closely correlated with HBV-induced HCC in vivo, reduced HBV replicative efficiency by affecting HBx-binding to cccDNA and increased anti-apoptotic HBx activity in vitro. This suggests that F30V (although hampering HBV's replicative capacity) may promote hepatocyte survival, so potentially allowing persistent production of viral progeny and initiating HBV-driven hepatocarcinogenesis. Investigation of viral genetic markers associated with HCC is crucial to identify those patients at higher risk of HCC, who hence deserve intensive liver monitoring and/or early anti-HBV therapy.

Contact toxicity of filter cake and Triplex powders from Ethiopia against Sitophilus oryzae

Contact toxicity of filter cake and Triplex powders from Ethiopia were evaluated against the rice weevil, Sitophilus oryzae (Linnaeus). The study was aimed at determining the lethal and effective concentrations and times for both powders against S. oryzae. The lethal concentrations for 50 and 99% mortality (LC50 and LC99) of filter cake and Triplex against S. oryzae were determined at 14 d after exposing 10 adults for 12 h to concrete arenas inside Petri dishes treated with filter cake concentrations of 0.5–8 g/m2 and Triplex concentrations of 1–9 g/m2. Lethal times for 50 and 99% mortality (LT50 and LT99) were determined at 14 d after exposing adults for 1–24 h to 3 g/m2 of filter cake and 9 g/m2 of Triplex. Effective concentrations (EC50 and EC99) and times (ET50 and ET99) for 50 and 99% reduction of adult progeny production were determined from reduction in adult progeny production relative to production in control treatments at 42 d after exposure to filter cake and Triplex. LC50 and LC99 values for S. oryzae adults were 0.70 and 8.49 g/m2, respectively, when exposed to filter cake and 2.27 and 21.38 g/m2, respectively, when exposed to Triplex. The corresponding LT50 and LT99 values were 3.13 and 27.21 h, respectively, for filter cake and 4.72 and 38.60 h, respectively, for Triplex. EC50 and EC99 values for progeny reduction were 0.57 and 7.95 g/m2, respectively, for filter cake and 2.77 and 18.82 g/m2, respectively, for Triplex. The corresponding ET50 and ET99 values were 2.57 and 17.73 h, respectively for filter cake and 3.39 and 24.74 h, respectively, for Triplex. S. oryzae exposed to filter cake produced significantly less number of insect damaged kernels and grain weight loss than those exposed to Triplex. Filter cake was more efficacious against S. oryzae than Triplex.

Effectiveness of essential oils from Ngaoundere, against post-harvest insect and fungal pests of maize: Poster

Successful storage of harvest is a matter of utmost importance in the Sudano-Guinean agro-ecological zone where intense cultivation takes place only once a year. Poor and rudimentary drying/storage methods, high relative humidity as well as inaccessibility to the chemical pesticides leave stored maize at the mercy of insect and fungal attack. Insect attack favours secondary attack by fungi; both leading to a fall in the nutritional, sanitary and organoleptic qualities of the stored maize. Thus, poor peasant farmers are left with the choice of locally available botanicals as alternatives to chemical pesticides. It is against this backdrop that this study seeks to determine the insecticidal efficacy of essential oils from the leaves of Chenopodium ambrosioides and Cupressus sempervirens together with their 50/50 binary combination against the maize weevil, Sitophilus zeamais, and the fungi: Rhizopus stolonifer and Aspergillus flavus on stored maize. Insect mortality and progeny inhibition and the inhibition of fungal invasion were evaluated. Pesticidal activities of both essential oils increased with ascending dose of application. 200 µL/kg of the binary combination caused 100% mortality within 14 days and it completely inhibited progeny production in the weevil. The mixture of the two oils showed additive effects against the weevils and fungi. The two essential oils in isolation significantly inhibited fungal spore invasion in 21 days of storage although A. flavus was less susceptible than R. stolonifer. Therefore both plants could provide active botanical pesticides against S. zeamais and fungal pests in stored maize.

Effectiveness of binary combinations of Plectranthus glandulosus leaf powder and Hymenocardia acida wood ash against Sitophilus zeamais (Coleoptera: Curculionidae): Poster

Combinations of botanicals could enhance biological activity against insects. This in turn, will reduce amount of botanical used in storage protection. In this issue, the bioassay was carried out on Sitophilus zeamais to assess the effectiveness of binary combinations of Hymenocardia acida wood ash and Plectranthus glandulosus leaf powder regarding adult toxicity, progeny inhibition, and reduction of damage and germination ability. Plectranthus glandulosus leaf powder, H. acida wood ash and their binary combinations significantly induced mortality of S. zeamais adult (P? 0.0001). The higher mortality rate was achieved by the highest content (40 g/kg) of H. acida wood ash (94.66%) and 25PG75HA (94.59%) within 14 days of exposure. The combinations of P. glandulosus leaf powder with H. acida at different proportions produced different interactions. The combination made up by 75% of P. glandulosus leaf powder with 25% of H. acida wood ash produced synergistic effect whereas that made up by 50% of each of two powders had antagonistic effect in weevil mortality. The three combinations of H. acida and P. glandulosus significantly reduced the progeny production. In term of inhibition of F1, the combination 25PG75HA revealed more effective than the two other. The grain damage and population increase were significantly reduced. In general, the non-infested maize grain had a good germination rate than the infested ones. The treatments did not have negative effect on seed germination. From These results, the two powders and their binary combinations could be used to reduce grain infestation by insect while taking in account the proportions of insecticidal powders implied in the combination.

Effects of Hemizygia welwitschii leaf extract fractions on postharvest infestation of maize by Sitophilus zeamais Motsculsky (Coleoptera: Curculionidae): Presentation

As part of on-going efforts to use eco-friendly alternatives to chemical pesticides, leaf powder of Hemizygia welwitschii was sequentially extracted in hexane, acetone and methanol. Bioassays were carried out to establish the most active fraction(s) against Sitophilus zeamais in maize. Maize grains (50 g) were treated with concentrations within the range 2, 4, 6, and 10 g/kg of extract and Azadirachta indica seed oil (positive control) in the laboratory. The total number of progeny emerging from grains infested separately with S. zeamais eggs, larvae and pupae were recorded. Adult mortality counts were carried out 1, 3, 7 and 14 d post-exposure. Acetone extract was more toxic to the eggs, larvae and pupae than the other extracts, inhibiting progeny production by 90.90%, 88.10% and 100%, respectively, at the concentration 10 g/kg. For the same concentration, A. indica seed oil reduced progeny production by 100% for eggs, 96.08% for larvae and 70.93% for pupae. Hexane extract was more potent to the adult weevil than the other extracts, recording 100% mortality for the concentration 10 g/kg within 14 d. LC50 values were 0.78 (Hexane), 5.52 (acetone) and 1.69 g/kg (methanol). Extracts of H. welwitschii leaves had sufficient efficacy to be a component of storage pest management package for S. zeamais.

Toxicity of fine powders, filter cake and Triplex against Sitophilus zeamais adults:

Filter cake and Triplex are powdered by-products of aluminum sulfate and soap factories, respectively. There is limited data about the use of these powders as grain protectants. This study was aimed at determining contact toxicity of both powders against Sitophilus zeamais, a common pest of stored grains. Lethal concentration of both powders to S. zeamais was determined by exposing 10 adults for 12 h in 9 cm diameter concrete arenas inside Petri dishes dusted with filter cake (0 - 8 g/m2) or Triplex (0 - 9 g/m2). Lethal time was determined by exposing adults to 3 g/m2 filter cake and 9 g/m2 Triplex for 1 to 24 h. Each treatment was replicated 3 times. At the intended exposure time, adults were transferred to 150-ml round plastic containers with 30 g of wheat and held at 28 degree Celsius and 65% r.h. for 14 d to determine mortality. Adult progeny production was determined after 42 d. A 50% mortality of adults was obtained at 0.61 g/m2 of filter cake and 1.61 g/m2 of Triplex concentrations with a 12 h exposure. The corresponding effective concentrations for 50% reduction of progeny production were 0.18 g/m2 of filter cake and 2.66 g/m2 of Triplex. Lethal times for 50% mortality of adults after exposure to 3 g/m2 of filter cake and 9 g/m2 of Triplex were 4.42 and 4.29 h, respectively. The corresponding effective times for 50% reduction of progeny production after exposure to 3 g/m2 of filter cake and 9 g/m2 of Triplex were 1.74 and 2.34 h respectively. The overall result indicated that filter cake was highly toxic to S. zeamais than Triplex. Therefore, filter cake is a potential powder to be included in the integrated pest management practice in small holder farmers’ storage structures after tested under real field conditions.

Toxicity of four Cuban botanical derivatives against two stored-products coleopteran pests: Poster

Plants are a source of substances for protection of stored products. The Cuban flora has not yet been fully studied as a source of pesticides for postharvest protection, partly due to its great diversity. The toxicity of four Cuban plant derivatives against Lasioderma serricorne (F.) and Sitophilus zeamais Motschulsky was investigated. The anti-insect activity of the powders and the essential oil from plants belonging to Asteraceae, Fabaceae and Piperaceae was tested. Mortality and emergence of adult insects and the repellent effect of products were evaluated. Two products derived from Piper aduncum subsp. ossanum, caused high mortality (81,6 and 100%), reduced emergence (27,9 and 0,4%) and exhibited strong repellent activity on L. serricorne. Against S. zeamais, treatments with the highest mortality values were stems of Lonchocarpus punctatus (72,4%), seeds and stems of Canavalia ensiformis (64,9 and 69,9%), and leaves of Tithonia diversifolia (67,2%). The progeny production of S. zeamais was inhibited by powders of L. punctatus stems (31,8%), C. ensiformis seeds (40,5%), leaves (43,7%) and stems (30,6%), and T. diversifolia leaves (38,7%). The stems of C. ensiformis, leaves of T. diversifolia and L. punctatus had the highest repellent effect. These products have potential for small-scale treatments of grains for protection against both insects, and P. aduncum subsp. ossanum-based products to control L. serricorne infestation in tobacco. Identification of local candidates to develop effective and safe pesticides offers new alternatives to the Cuban agriculture in the control of storage pests.

Efficacy of seven Turkish diatomaceous earths against Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae: Bruchninae) on stored chickpea: Presentation

In this study, insecticidal efficacy of seven different local diatomaceous earths (DE) obtained from different deposits in Turkey together with two commercial DEs, Silicosec® (Biofa AG- Germany) and Desect® (Ep Naturals- America) against Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae: Bruchninae) an important pest of stored chickpea at five different concentrations (100, 300, 500, 1000 and 1500 ppm) was evaluated. The local DEs were coded as BGN, BHN, AG2N, AC2N, CB2N, CCN, FB2N. Mortality of the adults was assessed after 1, 3, 5 and 7 days of exposure, and consequently progeny (F1) production on treated chickpeas was recorded 42 days later. The tests were carried out under laboratory conditions of 25±1 °C, 55±5 % R.H. in a dark place. The most effective DEs after 1 day of exposure were CCN, AG2N and BHN causing 75%, 59%, 58% mortalities, respectively at 1500 ppm concentration. Silicosec®, Desect®, BGN, AC2N, applied at 1500 ppm concentration achieved 98-100% mortality of C.maculatus after 7 days of exposure, showing similar high insecticidal efficacy. The CCN, BHN, AG2N and CB2N caused 97-99% reduction in progeny (F1) production. Generally, increasing concentration significantly reduced the progeny production. In conclusion, this study has shown that three Turkish DEs, namelyCCN, AG2N and BHN highly toxic to C. maculatus after 3 days of exposurein comparison with commercial DEs Silicosec® and Desect®. These local DEs could be used in the management of pests of stored chickpea.

Chlamydia trachomatis fails to protect its growth niche against pro-apoptotic insults

Chlamydia trachomatis is an obligate intracellular bacterial agent responsible for ocular infections and sexually transmitted diseases. It has been postulated that Chlamydia inhibits apoptosis in host cells to maintain an intact replicative niche until sufficient infectious progeny can be generated. Here we report that, while cells infected with C. trachomatis are protected from apoptosis at early and mid-stages of infection, they remain susceptible to the induction of other cell death modalities. By monitoring the fate of infected cells by time-lapse video microscopy and by analyzing host plasma membrane integrity and the activity of caspases, we determined that C. trachomatis-infected cells exposed to pro-apoptotic stimuli predominately died by a mechanism resembling necrosis. This necrotic death of infected cells occurred with kinetics similar to the induction of apoptosis in uninfected cells, indicating that C. trachomatis fails to considerably prolong the lifespan of its host cell when exposed to pro-apoptotic insults. Inhibitors of bacterial protein synthesis partially blocked necrotic death of infected cells, suggesting that the switch from apoptosis to necrosis relies on an active contribution of the bacteria. Tumor necrosis factor alpha (TNF-α)-mediated induction of necrosis in cells infected with C. trachomatis was not dependent on canonical regulators of necroptosis, such as RIPK1, RIPK3, or MLKL, yet was blocked by inhibition or depletion of CASP8. These results suggest that alternative signaling pathways regulate necrotic death in the context of C. trachomatis infections. Finally, consistent with the inability of C. trachomatis to preserve host cell viability, necrosis resulting from pro-apoptotic conditions significantly impaired production of infectious progeny. Taken together, our findings suggest that Chlamydia’s anti-apoptotic activities are not sufficient to protect the pathogen’s replicative niche.

Effect of Delayed Mating on Longevity and Reproductive Performance of Lasioderma serricorne (Coleoptera: Anobiidae).

In recent times, research has focused on integrated pest management approaches using nonchemical alternatives such as mating disruption for the control of stored product insect pests. In this study, we examined the effect of imposed delayed mating on the longevity and reproductive performance of the cigarette beetle, Lasioderma serricorne (F.), a serious insect pest of value added grain-based products, tobacco products, and spices. Delayed mating, progressing 0-14 d, was imposed on both sexes simultaneously, on males only, and on females only. Insects were observed daily for longevity, and F1 progeny was recorded 7-10 wk after mating pairs were placed together. Unmated adults lived significantly longer than mated adults, and mated females lived significantly longer than mated males. However, the length of the period of mating delay did not significantly affect the longevity of mated adults. Progeny production decreased with the age of adults at mating. The number of progeny produced when mating delay was imposed on both sexes simultaneously or on females only was significantly lower than when mating delay was imposed on males only. Hence, females were more adversely affected by delayed mating than males. Findings from this study may provide information for the development of mating disruption techniques that can delay mating and may be effective in keeping populations of L. serricorne below levels that would warrant a control action.

Evaluation of insecticidal efficacy and persistence of Nigerian raw diatomaceous earth against Callosobruchus maculatus (F.) on stored cowpea

The insecticidal efficacy and persistence of Nigerian raw diatomaceous earth (DE) were evaluated in the laboratory on cowpea against Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae). The raw DE was applied to 1.5 kg lots of cowpea seeds at 0 (untreated control), 250, 500, 750, 1000 and 1500 mg/kg, and a commercial DE formulation (Protect-It®) applied at 1000 mg/kg was included in the test as positive (treated) control. The treated cowpea seeds were kept under ambient laboratory conditions (26 - 34°C and 24 - 93% RH. Bioassays were conducted on samples taken from each treatment at the day of storage and every 30 d for 6 consecutive months. Adult C. maculatus were exposed for 3 and 5 d to the samples and adult mortality was assessed over this exposure interval and progeny production and seed damage were assessed after additional 30 d. On freshly treated cowpea, both the raw DE and Protect-It® were highly effective against C. maculatus causing 100% adult mortality following 5 d of exposure. In general, the raw DE was less persistent on cowpea providing complete adult mortality only for two months. Protect-It® on the other hand was stable over the 6- month period of storage causing 95.8 to 100% adult mortality. None of the treatments completely inhibited progeny production after 2-3-moths storage period. The results of this study indicated that Protect-It® may provide suitable protection for 6 months against C. maculatus, but the raw DE in its present state is not suitable for long-term protection against this insect pest.

Effect of delayed mating on reproductive performance of Lasioderma serricorne (F.) (Coleoptera: Anobiidae): Presentation

With the ban of methyl bromide and the many problems associated with the use of other synthetic chemicals, current research have focused on non-chemical alternatives and integrated pest management approach for the control of stored product insect pests. Mating disruption is one technique being investigated for its effect on stored product insects. In this study, we determined the effect of age at mating on the reproductive rate and longevity of the cigarette beetle, Lasioderma serricorne (Coleoptera: Anobiidae). We disrupted the mating approach by delaying the insects from mating for different time periods in days. Same age virgin male and female cigarette beetles were paired to mate soon after emergence (0 d old), or delayed from mating for 1–14 d. In another experiment, we maintained the age of the male at 0 d old and varied the age of the female from 0– 14 d old and vice versa. Insects were observed daily for longevity and F1 progeny was recorded 7–10 weeks after mating pairs were put together. Progeny production generally decreased with age of adults at mating. The number of F1 progeny produced by same age adults varied from 10 per female to 59 per female. Similarly, the number of progeny decreased the longer one sex was delayed from mating. Findings from this study may provide information for the development of mating disruption techniques that can delay mating and may be effective in keeping populations of L. serricorne below levels that would warrant a control action.

Herpesvirus Infections in Patients Treated with the Mood Stabilizer Valproic Acid: A Nested Case-Control Study in the Spanish Primary Care Database, BIFAP

Purpose: The objective of this study is to evaluate the risk of infections for herpesviruses in patients exposed to Valproic acid and derivatives (VPA) in the Spanish research database BIFAP. Methods: We performed a case-control study nested in a primary cohort selected from the Spanish primary care population-based research database BIFAP over the period 2001 to 2015. The events of interest were those diseases caused by any of the herpesviruses known to infect humans, specifically. For each case, up to 10 controls per case matched by age, gender and calendar date were randomly selected using risk set sampling. A conditional logistic regression was used to compute adjusted odds ratios (OR) and their 95% confidence intervals (95%CI) for infection for herpesviruses associated to the use of VPA after adjusting for potential confounders. Results: Current use of VPA was associated with a trend towards a reduced risk of infection by herpesviruses as compared to non-users (OR 0.84; CI95% 0.7-1.0), being these differences marginally significant (p=0.053). Among current users, a trend to a decreased risk with treatment durations longer than 90 days was also observed. Conclusions: The results of this study show a trend to a reduced risk of infection for herpesviruses in patients exposed to VPA, especially in those with treatment durations longer than 90 days. These results are consistent with in vitro studies showing that, in cultured cells, VPA inhibits the production of infectious progeny of different enveloped viruses causing relevant human and veterinary diseases, including herpesviruses. Funding Statement: Work at Centro de Biologia Molecular Severo Ochoa was supported by grants from the Spanish Ministerio de Economia y Competitividad (AGL2014-52395-C2-1-R and AGL2017-84097-C2-1- R), and by an institutional grant from the Fundacion Ramon Areces and Banco Santander Central Hispano. Work at INIA (MAM-A) was supported by grant AGL2014-56518-JIN. Declaration of Interests: The authors declare no conflict of interest. Ethics Approval Statement: The scientific committee of BIFAP granted a positive opinion to the study protocol (#08/2015). The investigators had access to only fully anonymized data, and under this condition, no specific ethics review was required according to Spanish law.