Monitoring for resistance to organophosphorus and pyrethroid insecticides in Varroa mite populations

The occurrence of resistance in Varroa mite populations is a serious threat to the beekeeping industry and to crops that rely on the honey bee for pollination. Integrated pest management strategies for control of this pest include the judicious use of insecticides. To monitor field populations of Varroa mite for insecticide resistance, a glass vial bioassay procedure was developed to use in the development of a resistance management strategy. Diagnostic concentrations needed to separate susceptible genotypes from resistant individuals were determined for cypermethrin (0.1 microg per vial), fluvalinate (5.0 microg per vial), malathion (0.01 microg per vial), coumaphos (10.0 microg per vial), diazinon (5.0 microg per vial), methomyl (0.5 microg per vial), propoxur (0.1 microg per vial), and endosulfan (2.5 microg per vial). Resistance to organophosphorus insecticides (malathion, coumaphos) and pyrethroids (cypermetrhrin, fluvalinate) was widespread in both La Media Ranch, TX, and Wewahitchka, FL, from 2007 to 2009. There was no resistance to endosulfan, diazinon, methomyl, and propoxur in field populations of Varroa mite in the two locations where resistance was monitored. The seasonal patterns of resistance in Wewahitchka were different from those of La Media Ranch. In the former location, the frequency of resistance to all insecticides tested decreased significantly from 2007 to 2009, whereas it increased in the latter location. Resistance levels were unstable, suggesting that resistance could be successfully managed. The results validate use of the glass vial bioassay to monitor for resistance in Varroa mite and provide the basis for the development of a resistance management strategy designed to extend the efficacy of all classes of insecticides used for control of Varroa mite.     

Distribution of entomopathogenic nematodes in Southern Cameroon

A first survey of entomopathogenic nematodes (EPN) was conducted in three agro-ecological zones of Southern Cameroon in 2007 and 2008. Entomopathogenic nematodes were recovered from 26 of 251 soil samples (10.4%). Three species, Heterorhabditis baujardi, Steinernema sp. A and Steinernema sp. B were found. The two steinernematids were considered unidentified species. Among the positive samples, 23 samples contained only H. baujardi (88.5%), two contained Steinernema sp. A co-occurring with H. baujardi (7.7%), and one sample contained Steinernema sp. B (3.9%). H. baujardi was frequent in forest and fruit crop (cocoa and oil palm plantations). Steinernema sp. A was found in a tree plantation of teak, Steinernema sp. B in a forest habitat. Nematodes were mostly present in acidic soils with pH ranging from 3.7 to 7.0. The highest EPN presence was recorded in sandy loam, sandy clay loam, sandy clay and clay soils. EPNs were not recovered in sand, loamy sand and clay loam soils. Using principal component analysis for elucidating the major variation patterns among sampling sites, four factors explaining for 73.64% of the overall variance were extracted. Factors were a combination of geographical (latitude, longitude, altitude), soil (pH, contents of sand, silt and clay, organic carbon, texture), and moisture (wilting point, field capacity) parameters as well as climatic parameters (mean annual rainfall, mean air temperature). Logistic regression and redundancy analyses (RDA) revealed that soil pH, longitude, available water and altitude were associated with presence and absence of EPN. Both logistic regression and RDA indicated that, increasing soil pH and longitude, associated with decreasing altitude, led to higher percentages of samples containing entomopathogenic nematodes.     

Sporotrichosis in sub-himalayan India

Sporotrichosis is endemic in the Sub-Himalayan belt, which ranges from the northern to the north-eastern Indian subcontinent. Similar to many parts of the developing world, sporotrichosis is commonly recognized clinically in this region however consolidated epidemiological data is lacking. We report epidemiological, clinical and microbiological data from a hundred culture positive cases of sporotrichosis. Out of 305 clinically suspicious cases of sporotrichosis, a total of 100 isolates were identified as Sporothrix schenckii species complex (S. schenckii) on culture. Out of the culture proven cases 71% of the cases presented with lymphocutaneous type of lesions while 28% had fixed localized type and 1% had disseminated sporotrichosis. Presentation with lesions on hands was most frequently seen in 32% with arm (23%) and face (21%) in that sequence. The male to female ratio was 1∶1.27. Age ranged from 1 ½ years to 88 years. Mean age was 43.25 years. Disease was predominantly seen in the fourth to sixth decade of life with 58% cases between 31 and 60 years of age. Since the first report from the region there has been a steady rise in the number of cases of sporotrichosis. Seasonal trends reveal that most of the patients visited for consultation in the beginning of the year between March and April. This is the first study, from the most endemic region of the Sub-Himalayan belt, to delve into epidemiological and clinical details of such a large number of culture proven cases over a period of more than eighteen years which would help in the understanding of the local disease pattern of sporotrichosis.     

Hirsutella thompsonii and Metarhizium anisopliae as potential microbial control agents of Varroa destructor,a honey bee parasite

The potential of Hirsutella thompsonii Fisher and Metarhizium anisopliae (Metschinkoff) as biological control agents of the parasitic mite, Varroa destructor Anderson and Trueman was evaluated in the laboratory and in observation hives. In the laboratory, time required for 90% cumulative mortality of mites (LT(90)) was 4.16 (3.98-4.42) days for H. thompsonii and 5.85 (5.48-7.43) days for M. anisopliae at 1.1 x 10(3) conidia mm(-2). At a temperature (34+/-1 degrees C) similar to that of the broodnest in a honey bee colony, Apis mellifera L., H. thompsonii [LC(90)=9.90 x 10(1) (5.86-19.35) conidia mm(-2) at Day 7] and M. anisopliae [LC(90)=7.13 x 10(3) (2.80-23.45) conidia mm(-2) at Day 7] both showed significant virulence against V. destructor. The applications of H. thompsonii to observation hives resulted in significant mortality of mites, and reduction of the number of mites per bee 21 and 42 days post-treatments. The treatments did not significantly affect the mite population in sealed brood. However, the fungus must have persisted because infected mites were still observed [82.97+/-(0.6)%] 42 days post-treatment. In addition, the fungus was found to sporulate on the host. A small percentage [2.86+/-(0.2)%] of dead mites found in the control hives also showed fungal infection, suggesting that adult bees drifted between hives and disseminated the fungus. H. thompsonii was harmless to the honey bees at the concentrations applied and did not have any deleterious effects on the fecundity of the queens. Microbial control with fungal pathogens provides promising new avenues for control of V. destructor and could be a useful component of an integrated pest management program for the honey bee industry.     

Developmental and wound-, cold-, desiccation-, ultraviolet-B-stress-induced modulations in the expression of the petunia zinc finger transcription factor gene ZPT2-2

The ZPT2-2 gene belongs to the EPF gene family in petunia (Petunia hybrida), which encodes proteins with TFIIIA-type zinc-finger DNA-binding motifs. To elucidate a possible function for ZPT2-2, we analyzed its pattern of expression in relation to different developmental and physiological stress signals. The activity of the ZPT2-2 promoter was analyzed using a firefly luciferase (LUC) reporter gene, allowing for continuous measurements of transgene activity in planta. We show that ZPT2-2::LUC is active in all plant tissues, but is strongly modulated in cotyledons upon germination, in leaves in response to desiccation, cold treatment, wounding, or ultraviolet-B light, and in petal tissue in response to pollination of the stigma. Analysis of mRNA levels indicated that the modulations in ZPT2-2::LUC expression reflect modulations in endogenous ZPT2-2 gene expression. The change in ZPT2-2::LUC activity by cold treatment, wounding, desiccation, and ultraviolet-B light suggest that the phytohormones ethylene and jasmonic acid are involved in regulating the expression of ZPT2-2. Although up-regulation of expression of ZPT2-2 can be blocked by inhibitors of ethylene perception, expression in plants is not induced by exogenously applied ethylene. The application of jasmonic acid does result in an up-regulation of gene activity and, thus, ZPT2-2 may play a role in the realization of the jasmonic acid hormonal responses in petunia.     

Proposed follow up programme after curative resection for lower third oesophageal cancer

Cyclins are indispensable elements of the cell cycle and derangement of their function can lead to cancer formation. Recent studies have also revealed more mechanisms through which cyclins can express their oncogenic potential. This review focuses on the aberrant expression of G1/S cyclins and especially cyclin D and cyclin E; the pathways through which they lead to tumour formation and their involvement in different types of cancer. These elements indicate the mechanisms that could act as targets for cancer therapy.