ODC 164.5: 174.7 Pinus sylvestris + I68 164.5 T h e ultra.structure of the different cell types in mature needles o f pine (Pinus silvestris L.) is described. The epidermal cells are protoplasma-free with prominent secondary a~alls. The sunken guard cells have chloroplasts o f a simple structure and many mitochondria. A hypodermal layer is formed by living vacuolated fiber cells. The mesophyll ...

The pharynx of Caenorhabditis elegans is a neuromuscular organ responsible for feeding, concentrating food by its pumping movement. A class of mutants, the eat mutants, are defective in this behavior. We have identified a novel eat gene, eat-20, encoding a unique transmembrane protein with three EGF motifs. Staining with a specific polyclonal antibody reveals that EAT-20 is expressed predominan...

Dorsal intercalation is a coordinated cell migration event that rearranges hypodermal cells during C. elegans embryogenesis, and that resembles cell intercalation in many systems from flies to mice. Despite its conservation, the molecular mechanisms that govern dorsal intercalation in worms have remained elusive. Here, we comment on our recent publication, Walck-Shannon et al.,(1) which begins ...

Vulval differentiation in Caenorhabditis elegans involves several fundamental cellular events, including cell fusion, division and migration. We have characterized the role of the lin-40 (also known as egr-1) gene in these cellular processes. LIN-40 is homologous to the metastasis-associated factor 1 (MTA1) in mammals, which has been identified as a component of the nucleosome remodeling and hi...

Activation of EGFR-Ras-MAPK signaling in vulval precursor cells (VPCs) by LIN-3/EGF from the gonad induces vulval development in C. elegans. The prevailing view is that LIN-3 overcomes an "inhibitory signal" from the adjacent hyp7 hypodermal syncytium. This view originated from observations indicating that inactivation of functionally redundant Synthetic Multivulva (SynMuv) genes in hyp7 can ac...

UNLABELLED We report the clinical-morphological study of a granular cell tumor in dermal/hypodermal junction and subcutaneous fat left breast of an 83-year-old woman with a family history of breast carcinoma. Mammography study showed a spiculated lesion in the lower inner quadrant with suspicion of malignancy. The results of fine needle puncture-aspiration were inconclusive. Subsequent tumorect...

The nematode parasites of Rhinella marina include species of the genus Rhabdias (Rhabdiasidae: Rhabditoidea). The present study describes Rhabdias paraensis sp. nov., which parasitizes the lungs of R. marina in Brazilian Amazonia. Of the more than 70 known species of this genus, 18 are parasites of bufonids, of which, eight are Neotropical. The new species described here is similar to Rhabdias ...

LET-756 is one of the two fibroblast growth factors (FGF) of Caenorhabditis elegans. We have previously shown that worms homozygote for the let-756 null allele (s2887) die at larval stage and that homozygotes for the partial loss-of-function allele (s2613) are viable but shorter than wild-type animals. We now show that expression of let-756 in any region of the s2887 worm can rescue the lethal ...

MOTIVATION Advances in high-resolution microscopy have recently made possible the analysis of gene expression at the level of individual cells. The fixed lineage of cells in the adult worm Caenorhabditis elegans makes this organism an ideal model for studying complex biological processes like development and aging. However, annotating individual cells in images of adult C.elegans typically requ...