BACKGROUND Growth and morphogenesis during development depend both on patterning genes, which assign positional information, and on genes that regulate mechanical forces. The dumpy gene of the fruit fly Drosophila melanogaster is an example of the latter class, with mutant phenotypes affecting size and shape of the limbs, thoracic cuticle, trachea and mouthparts. RESULTS The genetically compl...

Cuticular proteins (CPs) are crucial components of the insect cuticle. Although numerous genes encoding cuticular proteins have been identified in known insect genomes to date, their functions in maintaining insect body shape and adaptability remain largely unknown. In the current study, positional cloning led to the identification of a gene encoding an RR1-type cuticular protein, BmorCPR2, hig...

Intergenomic evolutionary conflicts increase biological diversity. In sexual conflict, female defence against males is generally assumed to be resistance, which, however, often leads to trait exaggeration but not diversification. Here, we address whether tolerance, a female defence mechanism known from interspecific conflicts, exists in sexual conflict. We examined the traumatic insemination of...

The waxy cuticle plays a very important role in plant resistance to various biotic and abiotic stresses and is an important characteristic of Welsh onions. Two different types of biangan Welsh onions (BG) were selected for this study: BG, a wild-type covered by wax, which forms a continuous lipid membrane on its epidermal cells, and GLBG, a glossy mutant of BG whose epidermal cells are not cove...

In Caenorhabditis elegans, the terminal differentiation of the hypodermal cells occurs at the larval-to-adult molt, and is characterized in part by the formation of a morphologically distinct adult cuticle. The timing of this event is controlled by a pathway of heterochronic genes that includes the relatively direct regulatory gene, lin-29, and upstream genes lin-4, lin-14 and lin-28. Using nor...

Parasitic nematodes cause chronic, debilitating infections in both livestock and humans worldwide, and many have developed multiple resistance to the currently available anthelmintics. The protective collagenous cuticle of these parasites is required for nematode survival and its synthesis has been studied extensively in the free-living nematode, Caenorhabditis elegans. The collagen synthesis p...

In molting animals, a cuticular extracellular matrix forms the first barrier to infection and other environmental insults. In the nematode Caenorhabditis elegans there are two types of cuticle: a well-studied collagenous cuticle lines the body, and a poorly-understood chitinous cuticle lines the pharynx. In the posterior end of the pharynx is the grinder, a tooth-like cuticular specialization t...

Measurements of electrical resistance appear to be useful indicators of porosity and related water permeability in insect cuticle. To develop an adequate understanding of how such measurements relate to the physical and structural properties of the integument, we made detailed determinations of resistance and impedance values for pronotal cuticle in adult male Periplaneta americana. The most co...

Although the mechanoreceptor organs of astigmatic mites are used extensively as taxonomic characters, knowledge of their fine structure is minimal. Mechanoreceptors include setiform sensilla and cupules, and light microscopy, scanning electron microscopy and transmission electron microscopy were used to investigate their morphology. Setiform sensilla are movable and arise from a socket of th...

background: uterine rupture at the site of a previous cesarean scar is an uncommon but catastrophic complication of pregnancy, which is associated with significant maternal and fetal morbidity and mortality. case presentation: a 30-year old woman at 24th week of gestation and complaint of pain, contractions and spotting was admitted in royan institute in tehran, iran. she had a past medical his...