Disease relevance of Malpighian Tubules

• Deletion of the baculovirus ecdysteroid UDP-glucosyltransferase gene induces early degeneration of Malpighian tubules in infected insects [1].
• The diuretic peptide leucokinin transforms (renal) Malpighian tubules of the yellow fever mosquito from a moderately tight epithelium to a leaky epithelium by increasing the chloride-conductance of the paracellular shunt pathway [2].

High impact information on Malpighian Tubules

• In addition, Kr is required for the development of the malpighian tubules, a posterior internal tissue that forms during later stages of embryogenesis [3].
• The appearance of urate oxidase activity in the Malpighian tubules of Drosophlia melanogaster is synchronized with the time of emergence of the imago from the puparium [4].
• The treatment with diethyl ether or chloroform does not induce puffing in the polytene cells of malpighian tubules and of midgut [5].
• In situ hybridization of ine transcripts to developing embryos revealed expression of this gene in several cell types, including the posterior hindgut, Malpighian tubules, anal plate, garland cells, and a subset of cells in the central nervous system [6].
• Two members of the Hawaiian picture-winged Drosophila, D. affinidisjuncta and D. hawaiiensis, display markedly different levels of alcohol dehydrogenase (alcohol: NAD+ oxidoreductase, EC 1.1.1.1) in the larval midgut and Malpighian tubules [7].

Chemical compound and disease context of Malpighian Tubules

• Arachidonic acid and prostaglandin E2 in Malpighian tubules of female yellow fever mosquitoes [8].
• The effects of dibutyryl adenosine 3',5'-cyclic monophosphate (DBcAMP) and bumetanide (both 10(-4) M) on transepithelial Na+, K+, Cl-, and fluid secretion and on tubule electrophysiology were studied in isolated Malpighian tubules of the yellow fever mosquito Aedes aegypti [9].

Biological context of Malpighian Tubules

• Molecular analysis of the rols genomic region reveals two variant transcripts of rols due to different transcription initiation sites, rols6 and rols7. rols6 mRNA is detectable mainly in the endoderm during differentiation as well as in malpighian tubules and in the epidermis [10].
• By injecting cosmid clones that include this region into lt mutant embryos, we have defined a 30-kb region that can transiently rescue the pigmentation defect in the Malpighian tubules [11].
• Basolateral transport of the prototypical type I organic cation tetraethylammonium (TEA) by the Malpighian tubules of Drosophila melanogaster was studied using measurements of basolateral membrane potential (V(bl)) and uptake of [(14)C]-labeled TEA [12].
• Ecdysone 20-monooxygenase, the cytochrome P-450 dependent monooxygenase which converts ecdysone to the active molting hormone 20-hydroxyecdysone had a low activity in the beginning of the instar, but showed a peak in both Malpighian tubules and fat body which coincided with the peak of 20-hydroxyecdysone in the hemolymph [13].
• When the Malpighian tubules (Mt) of the house cricket (Acheta domesticus) are treated with dibutyryl adenosine 3', 5'-cyclic monophosphate (db-cAMP; 1 mM), which causes a doubling in secretion rate, more than 50% of the cell volume is occupied by vesicles within 420 sec of exposure [14].

Anatomical context of Malpighian Tubules

• Transcripts from the introduced Yp1 were not found in male flies but appeared on a normal developmental schedule in adult females, accumulating in their body walls and ovarian follicles but not in guts or malpighian tubules [15].
• Close to 500 protein spots from gonadal tissues (testis and ovary) and nongonadal tissues (malpighian tubules and brain) were analyzed and protein divergence was calculated based on presence vs absence [16].
• NDAE1 is expressed throughout Drosophila development in the central and peripheral nervous systems, sensilla, and the alimentary tract (Malpighian tubules, gut, and salivary glands) [17].
• During embryogenesis in Drosophila, Sox100B is expressed in two rows of large intestinal cells, in midgut basophilic cells, in the Malpighian tubules and at the posterior cap of gonadal mesoderm [18].
• Larval epidermis and fat body are also able to transform 2,22,25-trideoxyecdysone into ecdysone; Malpighian tubules and midgut hydroxylate the precursor at C-2 but are apparently unable to hydroxylate both at C-22 and C-25 [19].

Associations of Malpighian Tubules with chemical compounds

• At higher concentrations the Aedes leucokinins 1 and 3 but not Aedes leucokinin 2 are also able to increase the rate of fluid secretion by the malpighian tubules [20].
• This was most pronounced in the distal part of the anterior Malpighian tubules, where rhodamine 123 was eventually precipitated on the luminal concretions [21].
• Glucose transport in Malpighian tubules of Locusta [proceedings] [22].
• Manduca has been previously shown, in physiological studies, to have an alkaloid (nicotine/morphine/atropine) pump at its excretory malpighian tubules [23].
• Extracts of the CC and abdominal nerves caused an increase in the rate of secretion and an increase in the level of cyclic AMP in the Malpighian tubules of fifth-instar R. prolixus [24].

Gene context of Malpighian Tubules

• Although byn is not expressed in the midgut or the Malpighian tubules, it is required for the formation of midgut constrictions and for the elongation of the Malpighian tubules [25].
• The transient cmg transcription in midgut and Malpighian tubules may suggest a potential function in cell junction formation and in epithelial tissue patterning [26].
• The urate oxidase (UO) gene of Drosophila melanogaster is expressed during the third-instar larval and adult stages, exclusively within a subset of cells of the Malpighian tubules [27].
• Whole mount in situ hybridizations revealed dKirI transcripts absent from embryos, but dKirII and dKirIII are expressed in the embryonic hind gut and in Malpighian tubules, respectively, thus covering the entire osmoregulatory system of the developing fly [28].
• Regulatory interactions and role in cell type specification of the Malpighian tubules by the cut, Krüppel, and caudal genes of Drosophila [29].

Analytical, diagnostic and therapeutic context of Malpighian Tubules

• The second method used a salicylate-selective microelectrode to measure the concentration of salicylate in fluid droplets secreted by isolated Drosophila Malpighian tubules set up in a Ramsay secretion assay [30].
• HPLC quantification of MMA and PBA accumulation into Malpighian tubules verified that MMA accumulation was via a mediated transport process, but suggested that PBA accumulation was by nonspecific binding [31].
• Nymphs and adult ticks were age graded by dissection of gut and Malpighian tubules and staining for lipid with Sudan red [32].
• Kynurenine-H3 transport and conversion to 3-hydroxykynurenine were studied in organ culture using the Malpighian tubules and developing eyes from wild type and the eye color mutants w, st, ltd, ca, and cn of Drosophila melanogaster [33].
• The SP-2 transcript was detected by Northern blot analysis in Malpighian tubules, in addition to the fat body where it was most abundant [34].

References