The extent of polylactosamine glycosylation of MDCK LAMP-2 is determined by its Golgi residence time

The increased polylactosamine glycosylation of LAMP-2 in MDCK cells cultured for 1 day relative to cells cultured for 3 days has been correlated with its slower rate of Golgi transit (Nabi and Rodriguez- Boulan, 1993, Mol. Biol. Cell., 4, 627-635). To determine if the differential polylactosamine glycosylation of LAMP-2 is a consequence of glycosyltransferase expression levels, the activities of beta1- 6GlcNAc-TV, beta1-3GlcNAc-T(i), beta1-2GlcNAc-TI, beta1, 4Gal-T, alpha2- 6sialyl-T, and alpha2-3sialyl-T were assayed and no significant differences in the activities of these enzymes in 1 and 3 day cell extracts were detected. During MDCK epithelial polarization, the Golgi apparatus undergoes morphological changes and apiconuclear Golgi networks were more evident in 3 day cells. Treatment with nocodazole disrupted Golgi networks and generated numerous Golgi clusters in both 1 day and 3 day cells. In the presence of nocodazole the differential migration of LAMP-2 in 1 and 3 day MDCK cells was maintained and could be eliminated by treatment with endo-beta-galactosidase, indicating that gross Golgi morphology did not influence the extent of LAMP-2 polylactosamine glycosylation. Nocodazole treatment did, however, result in the faster migration of LAMP-2 which was not due to modification of core N-glycans as the precursor form of the glycoprotein migrated with an identical molecular size. Following incubation at 20 degrees C, which prevents the exit of proteins from the trans-Golgi network, the molecular size of LAMP-2 increased to a similar extent in both 1 and 3 day MDCK cells. Extending the time of incubation at 20 degrees C did not influence the size of LAMP-2, demonstrating that its glycosylation is modified not by its retention within the Golgi but rather by its equivalent slower Golgi passage at the lower temperature in both 1 and 3 day cells. An identical effect was observed in nocodazole treated cells, demonstrating that Golgi residence time determines the extent of LAMP-2 polylactosamine glycosylation, even in isolated Golgi clusters.      

The vascular endothelial growth factor (VEGF) family: angiogenic factors in health and disease

Vascular endothelial growth factors (VEGFs) are a family of secreted polypeptides with a highly conserved receptor-binding cystine-knot structure similar to that of the platelet-derived growth factors. VEGF-A, the founding member of the family, is highly conserved between animals as evolutionarily distant as fish and mammals. In vertebrates, VEGFs act through a family of cognate receptor kinases in endothelial cells to stimulate blood-vessel formation. VEGF-A has important roles in mammalian vascular development and in diseases involving abnormal growth of blood vessels; other VEGFs are also involved in the development of lymphatic vessels and disease-related angiogenesis. Invertebrate homologs of VEGFs and VEGF receptors have been identified in fly, nematode and jellyfish, where they function in developmental cell migration and neurogenesis. The existence of VEGF-like molecules and their receptors in simple invertebrates without a vascular system indicates that this family of growth factors emerged at a very early stage in the evolution of multicellular organisms to mediate primordial developmental functions.     

Allergenic and immunogenic properties of industrial dust of the cotton factory

The results of the determination of the allergenic and immunogenic properties of industrial dust of the cotton factory complex are presented. The antigen of industrial dust consists of, at least, 5 antigenic components. The presence of common antigenic determinants in the antigen of industrial dust and in cotton pollen antigen has been established. The administration of relatively large doses of the allergen according to a shortened schedule has been experimentally shown to enhance the curative effectiveness of specific therapy.     

Effects of age and leg length upon central loop of the Gastrocnemius-soleus H-reflex latency

Background  

central loop of the gastrocnemius-soleus H-reflex latency (T_c) that looks promising in the diagnosis of S1 radiculopathy; has been investigated in a few studies and only two of them have focused on the constitutional factors affecting it. Although leg length has been shown to contribute to the T_c, the role of age is controversial. More confusing, none of the previously performed studies have used strict criteria to rule out subclinical neuropathy, so the results could be misleading. This study has been performed to determine the influence of leg length and age on T_c among a carefully selected group of healthy volunteers.     

ERRATUM: Effects of Loading on the Biomechanical Behavior of Molars of Homo,Pan, and Pongo. Am J Phys Anthropol 109:211–227.

ERRATUM: Macho GA and Spears IR. 1999. Effects of Loading on the Biomechanical Behavior of Molars of Homo, Pan, and Pongo. Am J Phys Anthropol 109:211–227. The correct title of the article is given above. The word “biochemical” should be read as “biomechanical.”     

Spatial Distribution and Fruiting Phenology of Protium heptaphyllum (Burseraceae) Determine the Design of the Underground Foraging System of Atta sexdens L. (Hymenoptera: Formicidae)

Leaf-cutting ants have long been recognized to forage via complex trail systems but the nature and the ecological drivers of the different foraging strategies adopted remain a key topic. Here, we described the spatiotemporal use of belowground foraging galleries by Atta sexdens L. in the Brazilian Atlantic forest, and examined the adaptive advantages of this foraging strategy. Protium heptaphyllum adult trees (DBH?>?10?cm), seed/seedling clumps and ant gallery entrances were mapped across two 1-ha plots during two consecutive fruiting seasons (2002 and 2004). We recorded 75 ca. 40?cm deep gallery entrances beneath 26 P. heptaphyllum trees at nest distances ranging from 14 to 57?m. Furthermore, gallery abundance and galleries associated with seed/seedling clumps correlated positively with P. heptaphyllum density. Our results indicate that A. sexdens was able to set a permanent system of underground galleries targeting P. heptaphyllum trees and their seeds on the ground. Such network of galleries was spatially arranged according to both the spatial distribution and abundance of P. heptaphyllum trees in a way that most gallery entrances were disposed beneath or in close periphery of P. heptaphyllum crowns. Our findings suggest that underground trail systems shaped by fruit resources represent a foraging strategy clearly more common than existing literature on the subject would suggest. In addition, it reinforces the notion that the spatiotemporal availability of resources combined with predation risk largely influence trail configurations as well as overall foraging strategies adopted by leaf-cutting ants.     

A novel isoflavone glycoside from Caragana alaica]

3-O-Rhamnopyranosylisorhamnetin, 3-O-glucopyranosylisorhamnetin, 7-O-galactopyranosylluteolin, quercitrin isoquercitrin, wistin, and a novel isoflavonoid, 3'-hydroxy-6,4'-dimethoxy-7-O-beta-D-glucopyranosylisoflavone, were isolated from the aerial parts of Caragana alaica. Of these, the previously described compounds were identified on the basis of their physicochemical and spectral characteristics, whereas the spectral analysis and conversion to a known compound, cladrastin, allowed the structural elucidation of the novel isoflavone glycoside.     

Regional features of sensitization of children to some noninfectious allergens

The results of epidemiological investigations within the frames of the ISAAC program are presented. Out of 2,870 children, 172 children (6.0%) with sensitization to some noninfectious (insect, pollen, medicinal) allergens were detected. The number of allergic children was found to be 10.4 +/- 1.8 to 28.2 +/- 3.0 per 1000 of urban child population. Specific features of the sensitization of urban children to regional insect, pollen and medicinal allergens were established. The clinical course of allergic diseases in children was characterized by polymorphism and a great variety of clinical symptoms with frequent lesions of the gastrointestinal tract and functional disturbances of the central nervous system, which adversely affected the school studies of children and the quality of their life. In the development of allergy in children such factors of risk as hereditary predisposition to allergy, allergic diathesis, focal infections and artificial feeding during the first year of life were also of great importance.     

Epidemiological characterisation of acute and chronic hepatitis B in Uzbekistan

The epidemiological survey of 126 foci with patients having acute hepatitis B (AHB) and 120 foci with patients having chronic hepatitis B (CHB) was conducted. The observation of the susceptible members of the family showed that a significantly higher level of infection was found in persons having contacts with CHB patients (44.4 +/- 2.3%) in comparison with the members of the families of AHB patients (33.2 +/- 2.3%). The study revealed that children under 14 years were actively involved into the epidemic process; in these children the highest levels of infection were observed in the families of AHB patients (40.2 +/- 3.7%) and CHB patients (57.1 +/- 3.5%). High detection rate of HbsAg were noted in brothers and sisters in the foci of AHB (42.3 +/- 6.4%) and the foci of CHB (52.3 +/- 5.4%), also in parents: 32.4 +/- 5.2% and 46.5 +/- 4.2%, in children: 28.8 +/- 3.4% and 35.6 +/- 3.6% respectively.