Yeast species affects feeding and fitness of Drosophila suzukii adults

Yeasts play an important role in the life cycle and biology of the insect pest Drosophila suzukii (Matsumura), commonly known as the spotted wing drosophila (SWD). Adult and larvae of this species are known to feed and benefit from yeast in their diet. In addition, yeasts were found to be attractive to SWD and were repeatedly found to be associated with SWD. Among those, Hanseniaspora uvarum is the most commonly mentioned. The present study explores the chemical composition and the effects of three H. uvarum strains and five yeast species (Saccharomyces cerevisiae, Candida sp., Issatchenkia terricola, Metschnikowia pulcherrima and Saccharomycopsis vini) in the diet of SWD adults. The different yeast species used in this study influenced mortality, fecundity and ingestion by SWD females. Hanseniaspora uvarum and S. vini were preferably ingested and increased fecundity of SWD females. The intra- and extracellular concentrations of compounds, such as amino acids, carbohydrates, sugar alcohols and organic acids, produced or consumed by yeasts differed among the species. Knowledge of the interaction of different yeast species with SWD and specific differences in the profile of compounds of yeast can help to improve the development of control strategies against the insect pest by promoting the ingestion of attract-and-kill formulations based on the combinations of yeasts and an appropriate insecticide

Persistence of a yeast-based (Hanseniaspora uvarum) attract-and-kill formulation against Drosophila suzukii on grape leaves

The production of phagostimulant and attractive volatile organic compounds (VOCs) by yeasts can be exploited to improve the efficacy of attract-and-kill formulations against the spotted wing drosophila (SWD). This study evaluated the persistence over one week of a yeast-based formulation under greenhouse conditions. Potted grape plants were treated with: (i) potato dextrose broth (PDB), (ii) PDB containing spinosad (PDB + S), and (iii) H. uvarum fermentation broth grown on PDB containing spinosad (H. u. + S). Laboratory trials were performed to determine the survival and the oviposition rate of SWD after exposure to treated leaves. Ion-exchange chromatography was performed to measure carbohydrates, sugar alcohols, and organic acids on leaf surfaces, while amino acids were assessed through liquid chromatography–mass-spectrometry. Additionally, the VOCs released by plants treated with H.uvarum were collected via closed-loop-stripping analysis and compared to those emitted by untreated leaves. A higher mortality was observed for adult SWDs in contact with H. uvarum containing spinosad compared to PDB containing spinosad. Generally, a decrease in the amounts of non-volatile compounds was observed over time, though numerous nutrients were still present one week after treatment. The application of the yeast-based formulation induced the emission of VOCs by the treated leaves. The concentration of 2-phenylethanol, one of the main VOCs emitted by yeasts, decreased over time. These findings describe the presence of potential phagostimulants and compounds attractive to SWD in a yeast-based attract-and-kill formulation and demonstrate the efficacy of the formulation over one wee

Volatile organic compounds in disease-resistant grapevine hybrids

Grapevine is one of the most important crop plants worldwide. Among many existing grapevine species, Vitis vinifera subsp. sativa is by far the most commonly used one in winemaking. However, this species is susceptible to many diseases such as downy or powdery mildew. For this reason, the use of pesticides has become essential in the grape production. One approach to overcome this problem was the generation of Vitis hybrids by crossing Vitis vinifera species with disease-resistant American or Asian species. Unfortunately, besides of resistance traits also negative quality compounds derive from these wild species and can be present in the obtained hybrids. Since volatile organic compounds (VOCs) play a major role in terms of grape quality, this work gives an inside into the aroma profile of various grapevine hybrids. Two different techniques were used: Headspace Solid-Phase Microextraction - Gas Chromatography with Mass Spectrometry (HS-SPME-GC-MS) and Proton Transfer Reaction - Mass Spectrometry (PTR-MS). These two complementary techniques allowed a differentiation of the 74 studied grapevine accessions according to their aromatic profile. These results are important for grapevine breeding as they can be employed both for positive and negative selection

Onset of clinical signs in children with HIV-1 perinatal infection. Italian Register for HIV Infection in Children.

OBJECTIVE: To investigate the timing of onset of each clinical sign in infants and children with HIV-1 perinatal infection. DESIGN AND METHODS: A total of 200 HIV-1-infected children followed-up from birth were studied. Failure and conditional probabilities were estimated by the Kaplan-Meier product-limit method. Cox proportional hazard analysis was used to evaluate independently associated factors. Results of 934 seroreverters were used to calculate reference values of CD4+ cell counts and predictivity of early signs. RESULTS: Median age at the onset of any sign was 5.2 months (range, 0.03-56 months). The probability of remaining asymptomatic was 19% [95% confidence interval (CI), 14-25.1] at 12 months and 6.1% (95% CI, 2.6-11.7) at 5 years. Lymphadenopathy (69.5%), splenomegaly (62.4%) and hepatomegaly (58.4%) were the most common signs in the first year of life. Peculiar to the first year of life (compared with subsequent ages) was the onset of primary HIV-1 hepatitis and diarrhoea (rate ratios, 23.3 and 15.2, respectively). When CD4+ cell counts in the asymptomatic stage (age, 2 months; range, 0.03-5.9 months) were below rather than above the fifth percentile in seroreverters, onset of signs was earlier [3 range, 0.03-19) versus 5 (range, 0.03-56) months]. Children manifesting signs before the 5.2-month breakpoint had a lower survival rate [74% (range, 65.9-82%) at 12 months and 45% (range, 32.9-57%) at 5 years] than children manifesting signs later [98% (range, 92.2-100%) at 12 months and 74% (range, 60.3-87.7%) at 5 years]. Children whose birthweight was < or = 2400 g had an earlier onset (24 months; range, 1-57 months) of severe conditions than children with higher birthweight (71 months; range, 1-71 months). Development of lymphadenopathy or hepatosplenomegaly within 3 months of life were reliable indicators of infection. CONCLUSIONS: This study describes the sequence of onset of signs in perinatal HIV-1 infection. Infection is shown to progress faster than in adults and in a different manner. Low birthweight, early decreased CD4+ cell counts, and early onset of signs are predictive of rapid progression

HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 INFECTION AND BREAST-MILK

Major questions are whether mothers infected with the Human Immunodeficiency Virus type 1 (HIV-1) transmit the virus through breast milk and the magnitude of the additional transmission risk. The demonstration of a dose-response effect is an epidemiological method to demonstrate causality. Thus, a study was carried out by the Italian Register for HIV Infection in Children on 961 children of known infection status. Duration of breast-feeding was considered as the level of exposure in 168 ever breastfed children. Results showed that duration of practice significantly increased the risk of transmission. The adjusted infection odds ratio for one day of breast- versus exclusive formula-feeding was 1.19 with narrow confidence limits (1.10-1.28). In a second study by the Register on 556 children of known infection status and derived prospectively, an infection odds ratio of 2.55 (confidence interval: 1.03-6.37) was calculated in breast- versus exclusively formula-fed children. Several lines of evidence, including the above-mentioned data from the Italian Register for HIV Infection in Children, showed a contribution of breast-feeding to mother-to-child HIV-1 transmission. Thus, this practice is now discouraged in HIV-1 infected mothers living in industrialized societies where formula feeding is practical and attainable. Mode of feeding was known in 2183 children enrolled in the Register and born to HIV-1 infected mothers since 1981. It could be observed that feeding habits of at-risk infants changed in Italy in the middle 1980s, when a large majority of subjects was identified at birth. However, women infected exclusively by the sexual route are often unconscious of being infected or even being at risk from infection and consequently their children are less frequently identified at birth than are children of women with a history of intravenous drug use. In industrialized areas, the former children remain at risk from milk-borne HIV-1 infection

Human immunodeficiency virus type 1 infection and breast milk. The Italian Register for HIV Infection in Children.

Major questions are whether mothers infected with the Human Immunodeficiency Virus type 1 (HIV-1) transmit the virus through breast milk and the magnitude of the additional transmission risk. The demonstration of a dose-response effect is an epidemiological method to demonstrate causality. Thus, a study was carried out by the Italian Register for HIV Infection in Children on 961 children of known infection status. Duration of breast-feeding was considered as the level of exposure in 168 ever breast-fed children. Results showed that duration of practice significantly increased the risk of transmission. The adjusted infection odds ratio for one day of breast- versus exclusive formula-feeding was 1.19 with narrow confidence limits (1.10-1.28). In a second study by the Register on 556 children of known infection status and derived prospectively, an infection odds ratio of 2.55 (confidence interval: 1.03-6.37) was calculated in breast- versus exclusively formula-fed children. Several lines of evidence, including the above-mentioned data from the Italian Register for HIV Infection in Children, showed a contribution of breast-feeding to mother-to-child HIV-1 transmission. Thus, this practice is now discouraged in HIV-1 infected mothers living in industrialized societies where formula feeding is practical and attainable. Mode of feeding was known in 2183 children enrolled in the Register and born to HIV-1 infected mothers since 1981. It could be observed that feeding habits of at-risk infants changed in Italy in the middle 1980s, when a large majority of subjects was identified at birth