Biogenesis of zinc storage granules in Drosophila melanogaster.

Membrane transporters and sequestration mechanisms concentrate metal ions differentially into discrete subcellular microenvironments for use in protein cofactors, signalling, storage or excretion. Here we identify zinc storage granules as the insect's major zinc reservoir in principal Malpighian tubule epithelial cells of Drosophila melanogaster The concerted action of Adaptor Protein-3, Rab32, HOPS and BLOC complexes as well as of the white-scarlet (ABCG2-like) and ZnT35C (ZnT2/ZnT3/ZnT8-like) transporters is required for zinc storage granule biogenesis. Due to lysosome-related organelle defects caused by mutations in the homologous human genes, patients with Hermansky-Pudlak syndrome may lack zinc granules in beta pancreatic cells, intestinal paneth cells and presynaptic vesicles of hippocampal mossy fibers.

Conserved metallomics in two insect families evolving separately for a hundred million years.

Μetal cofactors are required for enzymatic catalysis and structural stability of many proteins. Physiological metal requirements underpin the evolution of cellular and systemic regulatory mechanisms for metal uptake, storage and excretion. Considering the role of metal biology in animal evolution, this paper asks whether metal content is conserved between different fruit flies. A similar metal homeostasis was previously observed in Drosophilidae flies cultivated on the same larval medium. Each species accumulated in the order of 200 µg iron and zinc and approximately ten-fold less manganese and copper per gram dry weight of the adult insect. In this paper, data on the metal content in fourteen species of Tephritidae, which are major agricultural pests worldwide, are presented. These fruit flies can be polyphagous (e.g., Ceratitis capitata) or strictly monophagous (e.g., Bactrocera oleae) or oligophagous (e.g., Anastrepha grandis) and were maintained in the laboratory on five distinct diets based on olive oil, carrot, wheat bran, zucchini and molasses, respectively. The data indicate that overall metal content and distribution between the Tephritidae and Drosophilidae species was similar. Reduced metal concentration was observed in B. oleae. Feeding the polyphagous C. capitata with the diet of B. oleae resulted in a significant quantitative reduction of all metals. Thus, dietary components affect metal content in some Tephritidae. Nevertheless, although the evidence suggests some fruit fly species evolved preferences in the use or storage of particular metals, no metal concentration varied in order of magnitude between these two families of Diptera that evolved independently for over 100 million years.

Growth and reproductive potential of Eisenia foetida (Sav) on various zoo animal dungs after two methods of pre-composting followed by vermicomposting.

Disposal of animal manure without treatment can be harmful to the environment. In this study, samples of four zoo animal dungs and one horse dung were pre-composted in two ways: (a) traditional composting and (b) bokashi pre-composting for 1month, followed by vermicomposting for 3months. The permanence (PEf) and reproductive potential (RP) of Eisenia foetida as well as the quality of vermicompost were evaluated. The PEf values and RP index of E. foetida were higher for samples pre-composted using the traditional composting method (98.7-88% and 31.85-16.27%, respectively) followed by vermicomposting (92.7-72.7% and 22.96-13.51%, respectively), when compared with those for bokashi pre-composted samples followed by vermicomposting, except for the horse dung sample (100% for both the parameters). The values of electrical conductivity (EC), cation exchange capacity (CEC), organic C, total N, available P, C/N ratio, and pH showed that both treatments achieved the norms of vermicompost (<4mScm-1, 40cmolkg-1, 20-50%, 1-4%, ≤20, 5.5-8.5, respectively). However, the maturity indices of vermicompost, namely, organic matter loss, N loss, and CEC/organic carbon (OC) ratio indicated that bokashi pre-composting followed by vermicomposting produced the highest values (98.7-70.7%, 97.67-96.65%, and 2.7-1.97%, respectively), when compared with the other method adapted in this study. Nevertheless, further studies with plants for plant growth evaluation are needed to assess the benefits and limitations of these two pre-composting methods prior to vermicomposting.

Effect of pollutants on the ergosterol content as indicator of fungal biomass.

Ergosterol content was determined in 20 white-rot fungi isolates and the values ranged from 2380 to 13060 microg g(-1) fungal biomass. Significant changes of ergosterol content according the physiological stage for Bjerkandera adusta 4312 and Coriolopsis gallica 8260 were found, showing the highest values during the stationary phase. However, in the case of Phanerochaete chrysosporium 3642, no changes were detected during growth. The effect of pollutants, such as heavy metals and fungicides, on the ergosterol content of C. gallica was determined. Heavy metals (Cu 80 ppm, Zn 50 ppm or Cd 10 ppm) and fungicides (thiram 3 ppm or pentachlorophenol 1.5 ppm) at concentrations that reduce the metabolic activity between 18% and 53% (pollutant-stressed cultures) did not affect the ergosterol content. Only the fungicide zineb (25 ppm) reduced significantly the ergosterol content in biomass basis. In soil experiments with Cu (80 ppm) or thiram (10 ppm) after 15 and 30 days of incubation, the ergosterol content in soil was linearly correlated to the fungal biomass C in both polluted and control soil cultures. The ergosterol content was independent of the presence or the absence of pollutants. Thus, these results indicate that ergosterol can be a useful indicator for fungal biomass in polluted soils, and can be applied for monitoring bioremediation processes.