Immunochemical and immunohistological expression of Lewis histo-blood group antigens in small intestine including individuals of the Le(a+b+) and Le(a−b−) nonsecretor phenotypes

Histological samples and total non-acid glycosphingolipids were prepared from small intestine of human cadavers with the Le(a+b+) and Le(a–b–) nonsecretor phenotypes and contrasted with the more common Lewis phenotypes. Glycolipid fractions were analysed by thin-layer chromatography and tested for Lewis activity with monoclonal antibodies reactive to Lewis epitopes. Paraffin-embedded small intestine sections were also fluorescently immunostained with anti-Lewis antibodies. Unlike the common Lewis positive phenotypes, we were immunochemically able to demonstrate the copresence of large amounts of Le^a and Le^b glycolipids in the Le(a+b+) sample. In addition we demonstrated increased formation of extended Lewis structures in this phenotype. By immunohistochemistry Le^a, Le^b and type 1 precursor chain epitopes could be demonstrated in the brush border. These results show that the expression of the Le(a+b+) phenotype at the erythrocyte phenotyping level parallels the small intestinal expression of this phenotype, and the patterns of Lewis antigen expressions are unique to this phenotype. By immunohistochemistry and immunochemistry we also demonstrated the presence of trace amounts of Lewis active glycoconjugates in the small intestine of the Le(a–b–) nonsecretor and Le(a+b–) samples. In the Le(a–b–) nonsecretor Le^a and Le^b activity was absent and type 1 precursor was present in brush border, while Le^b activity was immunohistologically demonstrated in the Golgi apparatus of the deep glands. Trace amounts of both Le^a and Le^b glycolipids were identified in this sample. In parallel trace Le^b activity could also be detected in the glycolipids of the Le(a+b–) sample and could be immunohistologically demonstrated to be fully expressed in occasional cells in the deep glands of the small intestine, a pattern quite dissimilar to that of the Le(a–b–) nonsecretor. The results in this paper show that the expression of Lewis glycoconjugates in the small intestine parallel the expression of Lewis erythrocyte phenotypes. However, inappropriate Lewis activity is also seen in individuals of other phenotypes and the mechanisms by which these Lewis antigens are made appears to be different for different phenotypes.Abbreviations FITC fluorescein isothiocyanate - HPLC high-performance liquid chromatography - NeuAc N-acetyl-d-neuraminic acid - RBC red blood cell - TLC thin-layer chromatography - TRITC tetramethyl rhodamine isothiocyanate     

Expression of Lewis histo-blood group glycolipids in the plasma of individuals of Le(a+b+) and partial secretor phenotypes

Red cell Lewis antigens are carried by glycosphingolipids passively absorbed from plasma. Plasma was collected from a spectrum of individuals with normal and unusual Lewis/secretor phenotypes in order to investigate the glycolipid basis for the unusual phenotypes. Samples were obtained from: a Le(a+b–) ABH nonsecretor who secreted Lewis substances; a Le(a+b–) partial secretor; Le(a+b+) partial secretors; Le(a+b+) secretors; and a full range of normal Lewis/secretor phenotypes as controls. The Le(a+b+) samples represented Polynesian, Asian and Réunion Island ethnic backgrounds. Nonacid glycolipids were prepared, separated by thin-layer chromatography, and then immunostained with potent monoclonal antibodies of known specificity. Despite different serological profiles of the Le(a+b–) and Le(a+b+) Polynesian samples, their plasma glycolipid expressions were very similar, with both Le^a and Le^b co-expressed. The copresence of Le^a and Le^b in Le(a+b+) samples is in marked contrast to Caucasians with normal Lewis phenotypes, who have predominantly either Le^a or Le^b. These results suggest that there is a range of the secretor transferases in different individuals, possibly due to different penetrance or to several weak variants. We also show that Lewis epitopes on longer and/or more complex core chains appear to be predominant in the Polynesian Le(a+b+) samples. The formation of these extended glycolipids is compatible with the concept that in the presence of reduced secretor fucosyltransferase activity, increased elongation of the precursor chain occurs, which supports the postulate that fucosylation of the precursor prevents or at least markedly reduces chain elongation.Abbreviations CBA chromatogram binding assay - TLC thin-layer chromatography     

黄土丘陵区人工柠条种植年限和坡位对土壤团聚体稳定性的影响

柠条(Caragana korshinskii Kom.)种植是黄土高原地区生态环境建设中重要的人工植被恢复措施。选择黄土丘陵区条带种植15、25和35年的柠条坡地,以荒草坡地为对照,运用Le Bissonnais法分析柠条种植不同年限和坡位对0—40 cm土层团聚体分布及其稳定性的影响。结果表明:长时间柠条种植对土壤团聚体稳定性的影响主要在0—20 cm土层;不同处理下土壤大团聚体(0.25 mm)含量总体表现为柠条35年柠条25年柠条15年荒草地,表明柠条种植年限增加促进了大团聚体的形成。从坡面尺度看,柠条平均重量直径整体表现为坡下坡上坡中;在上坡的柠条35年样地具有最大值(3.08 mm),但在下坡荒草地显著高于柠条林地(P0.05)。基于相对消散指数和相对机械破碎指数,上中坡土壤团聚体均对消散作用和机械破碎作用较敏感,而下坡的下层土壤团聚体对破碎作用更敏感。冗余分析表明,土壤有机碳和粘粒含量与柠条平均重量直径呈显著正相关关系(P0.05)。种植年限是影响土壤团聚体稳定性的主要因素,解释了30.4%的变异;其次是土层(2.75%)和坡位(0.61%)。总体而言,柠条种植年限增加有利于促进黄土丘陵区土壤团聚体稳定性提升,但这种影响在不同坡位具有差异:在上中坡团聚体稳定性均随种植年限增加而增强,在下坡则先降后增。     

Cloning of the Lentinula edodes B mating-type locus and identification of the genetic structure controlling B mating

During the life cycle of heterothallic tetrapolar Agaricomycetes such as Lentinula edodes (Berk.) Pegler, the mating type system, composed of unlinked A and B loci, plays a vital role in controlling sexual development and resulting formation of the fruit body. L. edodes is produced worldwide for consumption and medicinal purposes, and understanding its sexual development is therefore of great importance. A considerable amount of mating type factors has been indicated over the past decades but few genes have actually been identified, and no complete genetic structures of L. edodes B mating-type loci are available. In this study, we cloned the matB regions from two mating compatible L. edodes strains, 939P26 and 939P42. Four pheromone receptors were identified on each new matB region, together with three and four pheromone precursor genes in the respective strains. Gene polymorphism, phylogenetic analysis and distribution of pheromone receptors and pheromone precursors clearly indicate a bipartite matB locus, each sublocus containing a pheromone receptor and one or two pheromone precursors. Detailed sequence comparisons of genetic structures between the matB regions of strains 939P42, 939P26 and a previously reported strain SUP2 further supported this model and allowed identification of the B mating type subloci borders. Mating studies confirmed the control of B mating by the identified pheromone receptors and pheromones in L. edodes.     

Biomechanical interactions of different mini-plate fixations and maxilla advancements in the Le Fort I Osteotomy: a finite element analysis

This study investigates the biomechanical interaction of different mini-plate fixation types (shapes/sizes and patterns) with segmental advancement levels on the Le Fort I osteotomy using the non-linear finite element (FE) approach. Nine models were generated under a standard 1-piece LeFort I osteotomy for advancement with 3, 6 and 9 mm distances and four mini-plates with three fixation patterns including LL, LI, and II patterns placed on the maxillae models by integrating computed tomography images and computer-aided design system. The axial and oblique occlusal forces were 250 N applied to each premolar/molar and 125 N applied at 30° inclination to the tooth long axis and from palatal to buccal, respectively. The relative micro-movement values between the two maxillary bone segments and maximum mini-plate stress increased obviously with maxilla advancement increment and the increasing trend can be fitted by exponential curve. The corresponding values in II mini-plate fixation presented apparently high values in all simulated cases. The mini-plate stress concentration locations were found at the bending regions to increase high fracture risk. The mini-plate yield strength can be mapped to a critical (limited) advancement for three types of fixations for safe consideration. This study concluded that L-shaped mini-plates with lateral fixation are recommended to provide better stability. The risk for mini-plate fracture and bone relapse increases when maxillary advancement is larger than a critical value of 5 mm in the Le Fort I osteotomy.     

Sticholysin I–membrane interaction: An interplay between the presence of sphingomyelin and membrane fluidity

Sticholysin I (St I) is a pore-forming toxin (PFT) produced by the Caribbean Sea anemone Stichodactyla helianthus belonging to the actinoporin protein family, a unique class of eukaryotic PFT exclusively found in sea anemones. As for actinoporins, it has been proposed that the presence of sphingomyelin (SM) and the coexistence of lipid phases increase binding to the target membrane. However, little is known about the role of membrane structure and dynamics (phase state, fluidity, presence of lipid domains) on actinoporins' activity or which regions of the membrane are the most favorable platforms for protein insertion. To gain insight into the role of SM on the interaction of St I to lipid membranes we studied their binding to monolayers of phosphatidylcholine (PC) and SM in different proportions. Additionally, the effect of acyl chain length and unsaturation, two features related to membrane fluidity, was evaluated on St I binding to monolayers. This study revealed that St I binds and penetrates preferentially and with a faster kinetic to liquid-expanded films with high lateral mobility and moderately enriched in SM. A high content of SM induces a lower lateral diffusion and/or liquid-condensed phases, which hinder St I binding and penetration to the lipid monolayer. Furthermore, the presence of lipid domain borders does not appear as an important factor for St I binding to the lipid monolayer.     

Developmental regulator Le.CDC5 of the mushroom Lentinula edodes: analyses of its amount in each of the stages of fruiting-body formation and its distribution in parts of the fruiting bodies

Immunoblot analysis of Le.CDC5 (842 amino acid residues), the expressed product of the cDNA of Le.cdc5 gene that has been previously reported to be most actively transcribed in primordia and small immature fruiting bodies of the basidiomycete Lentinula edodes, showed that the primordia, immature fruiting bodies and mature fruiting bodies contain similar amounts of Le.CDC5 protein. This indicates that the Le.CDC5 protein molecules synthesized in the beginning and early stage of fruiting-body formation remains in mycelial tissues even after small immature fruiting bodies developed and matured. Immunohistochemical analysis showed that Le.CDC5 is present everywhere in the mycelial tissues of immature fruiting body, but prehymenophore, the border between pileus and stipe, and the bottom of stipe seem likely to contain larger amounts of Le.CDC5. Within the hymenophore of mature fruiting body, the hymenium (in/on which a large number of basidia and basidiospores are formed) contains the Le.CDC5 most exclusively.     

Stratégie cynégétique et mode de vie à l'Azilien ancien dans le Bassin parisien : les apports de l'exploitation des chevaux du Closeau (niveau inférieur ; Rueil-Malmaison, Hauts-de-Seine)

The Closeau's lower level (Rueil-Malmaison, Hauts-de-Seine) brought evidence of Early Azilian occupations, in which the horse were the main prey. This paper present the zooarchaeological results of the equid's processing, according to the occupation units 4 and 46. The horse acquisition show that chase-approach hunts were the tactic employed, by a single individual or some small bands. The equids hunts' repetition testify that such activities took place at different moments of the year, especially in autumn and at the end of winter-springtime. These data allow a better understanding of the reasons that can explain why all phases of the animal processing were found in the inside of the occupation structures. The consumption of horse's meat and offal seems to take place only partly in situ. The units 4 and 46 can be interpreted as hunting camps, periodically use par Early Azilian bands. Such function of the site may signify that the mobility of these bands could integrated some traits of logistical pattern to a certain extent, but until now their lifeway stay unclear without new discoveries.     

A uniquely modern human pattern of endocranial development. Insights from a new cranial reconstruction of the Neandertal newborn from Mezmaiskaya

The globular braincase of modern humans is distinct from all fossil human species, including our closest extinct relatives, the Neandertals. Such adult shape differences must ultimately be rooted in different developmental patterns, but it is unclear at which point during ontogeny these group characteristics emerge.Here we compared internal shape changes of the braincase from birth to adulthood in Neandertals (N = 10), modern humans (N = 62), and chimpanzees (N = 62). Incomplete fossil specimens, including the two Neandertal newborns from Le Moustier 2 and Mezmaiskaya, were reconstructed using reference-based estimation methods. We used 3D geometric morphometrics to statistically compare shapes of virtual endocasts extracted from computed-tomographic scans. Throughout the analysis, we kept track of possible uncertainties due to the missing data values and small fossil sample sizes.We find that some aspects of endocranial development are shared by the three species. However, in the first year of life, modern humans depart from this presumably ancestral pattern of development. Newborn Neandertals and newborn modern humans have elongated braincases, and similar endocranial volumes. During a ‘globularization-phase’ modern human endocasts change to the globular shape that is characteristic for Homo sapiens. This phase of early development is unique to modern humans, and absent from chimpanzees and Neandertals.Our results support the notion that Neandertals and modern humans reach comparable adult brain sizes via different developmental pathways. The differences between these two human groups are most prominent directly after birth, a critical phase for cognitive development.     

Phlebotomine sandflies associated with a focus of cutaneous leishmaniasis in Valle del Cauca, Colombia

Abstract. A survey was made of the phlebotomine sandfly fauna of La Guaira, a village with coffee plantations near Cali, Colombia, from which cases of American cutaneous leishmaniasis had been reported due to Leishmania (Viannia) panamensis and Le. ( V. ) braziliensis. Among six species of sandfly collected on human bait, Lutzomyia youngi was most important in terms of biting nuisance. Lu. columbiana, Lu. lichyi and Lu. scorzai as well as Lu. youngi adults occurred throughout the year. Sandfly man-biting activity occurred throughout the night and was highest within 2 h of sunset. Despite its abundance in nocturnal samples, Lu. youngi was rarely taken in diurnal resting site collections. In contrast, Lu. lichyi was collected on tree-trunks during the day in large numbers and was the only species biting in daylight. The implications of these and other findings for leishmaniasis control measures in La Guaira are considered.