We review eleven Astrotischeria Puplesis & Diškus (Lepidoptera: Tischeriidae) species which possess a novel character for the Tischeriidae family: a highly modified valva of the male genitalia with one ventral and two dorsal lobes (or processes). The species are distributed in the Americas, including the USA, Caribbean (St. Thomas), Central America (Belize, Guatemala and Honduras), and South America (Ecuador, Bolivia, and Brazil). Species for which the biology has been studied are associated with host plants from Asteroidea of the Asteraceae family. The following seven species are described as new: Astrotischeria trilobata Diškus & Stonis, sp. nov., A. amazonica Diškus & Stonis, sp. nov., A. maya Diškus & Stonis, sp. nov., A. selvica Diškus, Carvalho-Filho & Stonis, sp. nov., A. casila Diškus & Stonis, sp. nov., A. onae Diškus & Stonis, sp. nov., and A. furcata Stonis & Diškus, sp. nov. A new informal species unit, the A. trilobata group, is designated for diagnostic purposes despite some doubts about monophyly of the group. Astrotischeria longeciliata (Frey & Boll) is synonymized here with the North American A. helianthi (Frey & Boll), a species not belonging to the A. trilobata group, syn. nov. For the first time, a method of rearing of adults from mining larvae, specifically adopted for Tischeriidae, is detailed. All species treated in the paper are illustrated with photographs or drawings of the adults, male genitalia, and, if available, the female genitalia, leaf mines and habitats. A distribution map for the species of the A. trilobata group and a scheme of the trophic relationships of the global Tischeriidae fauna are also provided.

The surface anionic groups of symbiote‐bearing and symbiote‐free strains of Crithidia deanei were compared by determining cellular electrophoretic mobility, by ultrastructural cytochemistry, and by identification of sialic acids by thin‐layer and gasliquid chromatography. Symbiote‐free Crithidia deanei has a highly negative surface charge (‐0.9984 μmċs‐1ċ V‐1ċ cm), which is slightly reduced (‐0.8527 μmċs‐1ċ V‐1ċ cm) by the presence of the endosymbiote. Treatment of both strains of C. deanei with neuraminidase decreased significantly the electrophoretic mobility of cells toward the cathodic pole, indicating the existence of exposed sialic acid residues responsible for the negative charge on the protozoan cell surface. Thin‐layer and gas‐liquid chromatography showed that N‐glycolyl‐ and N‐acetylneuraminic acids were present in both strains of C. deanei.

In the developing nervous system migrating neurons and growing axons are guided by diffusible and/or substrate-bound cues, such as extracellular matrix-associated laminin. In a previous work we demonstrated that laminin molecules could self-assemble in two different manners, giving rise to matrices that could favor either neuritogenesis or proliferation of cortical precursor cells. We investigated whether the ability of astrocytes to promote neuritogenesis of co-cultivated neurons was modulated by the assembling mode of the laminin matrix secreted by them. We compared the morphologies and neuritogenic potentials of laminin deposited by in vitro-differentiated astrocytes obtained from embryonic or neonatal rat brain cortices. We showed that, while permissive astrocytes derived from embryonic brain produced a flat laminin matrix that remained associated to the cell surface, astrocytes derived from newborn brain secreted a laminin matrix resembling a fibrillar web that protruded from the cell plane. The average neurite lengths obtained for E16 neurons cultured on each astrocyte layer were 198±22 and 123±13 μm, respectively. Analyses of surface-associated electrostatic potentials revealed that embryonic astrocytes presented a pI of -2.8, while in newborn cells this value was -3.8. Removal of the sialic acid groups on the embryonic monolayer by neuraminidase treatment led to the immediate release of matrix-associated laminin. Interestingly, laminin reassembled 1 hour after neuraminidase removal converted to the features of the newborn matrix. Alternatively, treatment of astrocytes with the cholesterol-solubilizing detergent methyl-β-cyclodextrin also resulted in release of the extracellular laminin. To test the hypothesis that sialic-acid-containing lipids localized at cholesterol-rich membrane domains could affect the process of laminin assembly, we devised a cell-free assay where laminin polymerization was carried out over artificial lipid films. Films of either a mixture of gangliosides or pure ganglioside GT1b induced formation of matrices of morpho-functional features similar to the matrices deposited by embryonic astrocytes. Conversely, films of phosphatidylcholine or ganglioside GM1 led to the formation of bulky laminin aggregates that lacked a defined structure. We propose that the expression of negative lipids on astrocytes can control the extracellular polymerization of laminin and, consequently, the permissivity to neuritogenesis of astrocytes during development.

The surface charpa of resident, thioglycollate‐elicited, and Trypanosoma cruzi‐ectivated mouse peritoneal macrophages was analyzed using cell electrophoresis. AN macrophages had a net negative surface charge. Activated macrophages had a lower zeta potential and a higher isoelectrophoretic point than resident and elicited macrophages. The populations of resident, elicited, and activated macrophages were heterogeneous in terms of surface charge. The analysis of the effect of the pH of the solution in which the macrophages were suspended on their cellular electrophoretic mobility (EPM) indicated that their surface contained both positively and negatively charged dissociating groups. The contribution of sialic acid residuos to the surface change was determined by analyzing the effect of neuraminidase treatment on the EPM of the cells. Activated mecrophages possessed more sialic add residuos exposed on their surface, and sensitive to the neuraminidase from Clostridium perfrigens, than resident and elicited macrophages. Treatment of the cells with the neuraminidase from Vibrio cholerae, however, reduced the surface charge of all macrophages in about the same extent. Macrophages had their mean EPM reduced when Incubated in the presence of Ca++, suggesting that some cell surface anionogenic sites have Ca++‐binding capacity.

The surface charge and surface carbohydrate residues of the virulent (freshly isolated from the fish blood) and avirulent forms (from culture) of Cryptobia salmositica and one strain of C. bullocki were studied. Measurements of the zeta potential of parasites showed that C. bullocki and the virulent form of C. salmositica had a net negative surface charge of about -15 mV, whereas the attenuated form of C. salmositica showed a surface charge of -7.9 mV. Enzymatic treatments of parasites with neuraminidase, trypsin, or phospholipase C indicated the presence of sialic acid residues, phosphate groups, and protein glycoconjugates as components of the Cryptobia surface that accounted for their surface charge. Residues of alpha-D-man, alpha- and beta-D-gal, alpha-D-galNAc, alpha-L-fuc, and D-glcNAc could be detected on the surface of all parasites by specific fluorescein isothiocyanate (FITC)- and colloidal gold-labeled lectins. The cell surface of the avirulent form of C. salmositica showed the strongest reactivity to almost all lectins tested. A remarkable binding pattern of lectins in the anterior region of parasites was observed.