2H1--a novel antigen involved in T lymphocyte triggering

A mAb anti-2H1, was produced against PHA-activated T cells from a lower primate, Aotus trivirgatus. Anti-2H1 reacted with 90% of peripheral T cells but was found to react with only 10% of thymocytes and some, but not all, leukemic T cell lines. 2H1 expression was dramatically increased when thymic cells were activated by Con A plus PMA. In contrast, anti-2H1 did not react with B cells, macrophages, null cells, or hematopoietic stem cell lines. More importantly, anti-2H1 antibody can induce T cell activation and proliferation in synergy with PMA or anti-T11(3). SDS-PAGE analysis of polypeptides immunoprecipitated with anti-2H1 showed two major polypeptides of 140 and 105 kDa. Thus, the 2H1 Ag can be distinguished from T3, T11, and 9.3 Ag. These results indicate that the 2H1 Ag appears to be involved in the activation of T lymphocytes.     

Hot‐Substrate Deposition of Hole‐ and Electron‐Transport Layers for Enhanced Performance in Perovskite Solar Cells

Charge transport layers play an important role in determining the power conversion efficiencies (PCEs) of perovskite solar cells (PSCs). However, it has proven challenging to produce thin and compact charge transport layers via solution processing techniques. Herein, a hot substrate deposition method capable of improving the morphology of high‐coverage hole‐transport layers (HTLs) and electron‐transport layers (ETLs) is reported. PSC devices using HTLs deposited on a hot substrate show improvement in the open‐circuit voltage (V_oc) from 1.041 to 1.070 V and the PCE from 17.00% to 18.01%. The overall device performance is then further enhanced with the hot substrate deposition of ETLs as the V_oc and PCE reach 1.105 V and 19.16%, respectively. The improved performance can be explained by the decreased current leakage and series resistance, which are present in PSCs with rough and discontinuous HTLs and ETLs.     

A Rapid High-Resolution High-Performance Liquid Chromatographic Method for Separating Glycan Mixtures and Analyzing Oligosaccharide Profiles

A sensitive and reproducible HPLC technology has been developed, capable of resolving sub-picomolar quantities of mixtures of fluorescently labeled neutral and acidic glycans simultaneously and in their correct molar proportions. The elution positions of standard glycans were determined in glucose units with reference to a dextran ladder, and incremental values for the addition of monosaccharides to oligosaccharide cores were calculated. This information was used to interpret the full oligosaccharide profiles of glycoproteins in a predictive manner based on arm specificity, linkage, and monosaccharide composition. The technique was applied to several systems. For example, a family of glycans isolated from the human parotid gland was extensively resolved on the basis of type and extent of outer arm fucosylation. Second, a serum IgG glycan pool was resolved into 20 peaks which were analyzed simultaneously by sequentially digesting the pool of sugars with exoglycosidase enzymes. In addition, alterations in the glycosylation of IgG associated with rheumatoid arthritis were directly monitored. The reproducibility of the separation system, the predictability of glucose unit values, and the quantitative response of the detection system for individual fluorescently labeled glycans also allowed the automatic analysis of neutral sugars using combinations of enzymes as in the reagent array analysis method (RAAM). In addition, the simultaneous resolution of both acidic (sialylated) and neutral products from the RAAM digestion allowed direct analysis of sialylated glycans, eliminating the previous need to remove sialic acid residues in a preliminary step. Overall, the technologies described here represent a significant advance toward faster, more automated, and more detailed glycan analysis.     

N-glycosylation and in vitro enzymatic activity of human recombinant tissue plasminogen activator expressed in Chinese hamster ovary cells and a murine cell line

To probe the effects of N-glycosylation on the fibrin-dependent plasminogenolytic activity of tissue-type plasminogen activator (t-PA), we have expressed a human recombinant t-PA (rt-PA) gene in Chinese hamster ovary (CHO) cells and in a murine C127 cell line. The resulting rt-PA glycoproteins were isolated and their associated N-linked oligosaccharide structures determined by using a combination of high-resolution Bio-Gel P-4 gel filtration chromatography, sequential exoglycosidase digestion, and methylation analysis. The results show that CHO rt-PA is N-glycosylated differently from murine C127 derived rt-PA. Further, both rt-PA's are N-glycosylated differently from t-PA derived from a human colon fibroblast and the Bowes melanoma cell line (Parekh et al., 1989), confirming that N-glycosylation of the human t-PA polypeptide is cell-type-specific. Both CHO and murine rt-PA were fractionated on lysine-Sepharose chromatography. The N-glycosylation of the major forms was analyzed and their fibrin-dependent plasminogenolytic activity determined by using an indirect amidolytic assay with Glu-plasminogen and a chromogenic plasmin substrate. The results suggest that the various forms of rt-PA differ from one another with respect to the kinetics of their fibrin-dependent activation of plasminogen. Together, these data support the notion (Wittwer et al., 1989) that N-glycosylation influences the fibrin-dependent catalytic activity of t-PA and that t-PA when expressed in different cell lines may consist of kinetically and structurally distinct glycoforms.     

The chromosome constitution of 1000 human spermatozoa

Summary Chromosomal analysis of 1000 spermatozoa from 33 normal men was performed using in vitro fertilization of zonafree golden hamster eggs. The frequency of abnormal sperm complements was 8.5%: 5.2% were aneuploid and 3.3% had a structural chromosome abnormality. The frequencies of hyperhaploid (2.4%) and hypohaploid (2.7%) sperm complements were not significantly different and all chromosome groups were represented among the aneuploid complements. The majority (22/33) of structurally abnormal complements had a chromosome break. The percentages of X and Y-bearing sperm were 53.9% and 46.1%, which is significantly different from the expected one to one ratio.     

The role of the 2H4 molecule in the generation of suppressor function in Con A-activated T cells

The molecular basis for the suppression generated in a concanavalin A (Con A)-activated T cell culture remains unknown. In this study, we have attempted to determine whether the 2H4 and 4B4 molecules on Con A-activated T cells play some role in the generation of suppression by such cells. We have shown that Con A-activated suppressor cells belong to the 2H4+ subset of T cells but not the 4B4+ (2H4-) subset. Con A-activated T cells exerted their optimal suppressor function on day 2 in culture, a time at which the expression of 2H4 on such cells was maximal and 4B4 was minimal. Furthermore, the stimulation of T cells with the higher concentration of Con A generated the stronger suppressor function. At the same time, both 2H4 expression and density were increased and 4B4 expression and density were decreased on such Con A-activated T cells. More importantly, the treatment of Con A-activated T cells with anti-2H4 antibody but not with anti-4B4, anti-TQ1, or anti-T4 antibodies can block the suppressor function of such cells. Taken together, the above results strongly suggest that the 2H4 molecule itself may be involved in the generation of suppressor function in Con A-activated T cells. The 2H4 antigen on such cells was shown to be comprised of 220,000 and 200,000 m.w. glycoproteins. Thus this study indicates that the 220,000 and 200,000 m.w. structure of the 2H4 molecule may itself play a crucial role in the generation of suppressor signals of Con A-activated cells.     

Two new species of Paramachaerium (Leguminosae) and a brief résumé of the genus

Paramachaerium Ducke, a genus of neotropical trees, has been known hitherto from three species,P. schomburgkii (Guyana and Brazil),P. ormosioides (French Guiana and Brazil), andP. gruberi (Panamá). Two new species are herein described,P. krukovii (western Brazil) andP. schunkei (Peru).     

The Contractile Mechanism in Cilia

A detailed analysis is made of the motion and the forces in the cilium of Sabellaria over the complete cycle. The results indicate that the stiffness of the cilium is directly related to the moments produced by the internal contractile elements. A sliding filament model is developed to generate the complete cycle of motion. The activation of the force-producing elements, the peripheral fibers, occurs over their entire length at once during the effective stroke. In the recovery stroke the sliding of peripheral fibers relative to each other produces activation. The peripheral fibers contribute to the stiffness of the cilium in the sliding filament model only when they are not free to slide because of cross-linkage. The model describes successfully the motion of a variety of types of cilia.