Immunocytochemical analysis of ascitic fluid due to cirrhosis. A contribution to understanding the origin of markedly atypical cells.

In some cases of ascitic fluid due to cirrhosis, benign mesothelial clusters may be observed, accompanied by markedly atypical cells that have been proposed to be abnormal macrophages, mesothelial cells or necrotic cells of hepatic origin. The aim of this study was to determine the origin of these cells with the use of a panel of monoclonal antibodies (MAbs) against cell surface antigens. Furthermore, the lymphocyte subpopulations were analyzed for a possible correlation with the presence of abnormal cells. Markedly atypical cells were found in 4 of 12 cases. They showed no phagocytosis of latex particles and were negative for MAbs My4 (CD14), HLE-1 (CD45), Leu M1 (CD15), CEA 3-13 and HEA-125. They reacted positively with BMA-120 and HLA-1. This staining pattern demonstrated the mesothelial origin of the markedly atypical cells. The profile of the lymphocyte subpopulations in the cases with markedly atypical cells was not different from the other cases. We propose that these cells are abortive cluster formations of mesothelial cells.     

Chromosomal and behavioral studies of Mexican Drosophila. III. Inversion polymorphism of D. pseudoobscura

Four new gene arrangements of chromosome 3 of Drosophila pseudoobscura are reported, as well as an updated phylogenetic sequence of the inversion polymorphism in this species. Evidence that the Tree Line gene arrangement of chromosome 3 was the original form in D. pseudoobscura, and that Central Mexico is the center of distribution of this species is discussed.     

Affinity surfactants as reversibly bound ligands for high-performance affinity chromatography

Pyridine was coupled covalently to a nonionic ethoxylated alcohol: octaethylene glycol n-hexadecyl ether. This modified surfactant was found to be a reversible, competitive inhibitor of horse serum cholinesterase. The surfactant bound irreversibly, in aqueous media, to octadecyl-bounded reverse phase silica particles commonly used for high-performance liquid chromatography. The amount of ligand bound was found to be 550 mumol/ml of packing, a concentration that is over 100 times higher than what can be normally bound to agarose affinity chromatography supports. With this packing, a 280-fold purification of cholinesterase from horse serum and a 79-fold purification of human serum cholinesterase were accomplished, with yields greater than 80%, using a 2-cm-long column and a 7-min elution time. The affinity surfactant could be eluted from the column using a 6:4 (v/v) mixture of methanol and isopropanol. This technique should be generally applicable in the development of biospecific supports for high-performance affinity chromatography.     

Parthenolide and DMAPT induce cell death in primitive CML cells through reactive oxygen species

Tyrosine kinase inhibitors (TKI) have become a first‐line treatment for chronic myeloid leuakemia (CML). TKIs efficiently target bulk CML cells; however, they are unable to eliminate the leukaemic stem cell (LSC) population that causes resistance and relapse in CML patients. In this study, we assessed the effects of parthenolide (PTL) and dimethyl amino parthenolide (DMAPT), two potent inhibitors of LSCs in acute myeloid leukaemia (AML), on CML bulk and CML primitive (CD34⁺lin^?) cells. We found that both agents induced cell death in CML, while having little effect on the equivalent normal hematopoietic cells. PTL and DMAPT caused an increase in reactive oxygen species (ROS) levels and inhibited NF‐κB activation. PTL and DMAPT inhibited cell proliferation and induced cell cycle arrest in G₀ and G₂ phases. Furthermore, we found cell cycle inhibition to correlate with down‐regulation of cyclin D1 and cyclin A. In summary, our study shows that PTL and DMAPT have a strong inhibitory effect on CML cells. Given that cell cycle arrest was not dependent on ROS induction, we speculate that this effect could be a direct consequence of NF‐κB inhibition and if this mechanism was to be evaded, PTL and DMAPT induced cell death would be potentiated.     

Design and synthesis of nonpeptide peptidomimetic inhibitors of renin

The desire to replace the amide backbone of renin inhibitors with a new scaffold led us to explore vinylogous amides (enaminones). An initial attempt proved unsuccessful, a result explained after the fact via docking experiments. Based on this lesson, we designed a different vinylogous amide scaffold which incorportated one or more pyrrolinone rings into the backbone. Three of the four compounds gave IC₅₀s in the 0.6 to 18 μM range. These compounds did not inhibit HIV-1 protease. Taken together, the results reported herein provide insights into the role of hydrogen bonding and steric interactions for binding to renin. © 1994 John Wiley & Sons, Inc.     

DNA Evidence of the Origin of Varroa jacobsoni Oudemans in the Americas

Randomly amplified polymorphic DNA (RAPD) was used to examine possible origin of Varroa jacobsoni Oudemans in the Americas. Among 64 primers screened, 2 primers provided variation which was informative for this study. All V. jacobsoni collected from the United States had the same banding pattern to that of mites collected from Russia, Morocco, Germany, Italy, Spain, and Portugal (Russian pattern). This banding pattern was different from the pattern found for mites collected from Japan, Brazil, and Puerto Rico (Japanese pattern). The Japanese pattern lacked a 766-bp band found in the Russian pattern (OPE-07). With primer OPP-03, the Russian pattern had a distinct band at 442 bp not found in the Japanese pattern. Two bands located at 675 and 412 bp were specific to the Japanese pattern. These results suggest that the V. jacobsoni of the United States is probably predominantly Russian in origin (via Europe), while the V. jacobsoni of Brazil and Puerto Rico are probably predominantly Japanese in origin.     

Localization of the Escherichia coli cell division protein FtsI (PBP3) to the division site and cell pole

FtsI, also known as penicillin-binding protein 3, is a transpeptidase required for the synthesis of peptidoglycan in the division septum of the bacterium, Escherichia coli . FtsI has been estimated to be present at about 100 molecules per cell, well below the detection limit of immunoelectron microscopy. Here, we confirm the low abundance of FtsI and use immunofluorescence microscopy, a highly sensitive technique, to show that FtsI is localized to the division site during the later stages of cell growth. FtsI was also sometimes observed at the cell pole; polar localization was not anticipated and its significance is not known. We conclude (i) that immunofluorescence microscopy can be used to localize proteins whose abundance is as low as approximately 100 molecules per cell; and (ii) that spatial and temporal regulation of FtsI activity in septum formation is achieved, at least in part, by timed localization of the protein to the division site.     

粘虫的发育和成活与环境湿度的关系——Ⅰ.卵和一龄幼虫

在25℃中,相对湿度为20—100%的范围内,卵的孵化率受湿度的影响不明显,在32℃中,相对湿度为40-100%的范围内,湿度对卵孵化率的影响亦不显著,但当相对湿度降至20%时,孵化率即有明显的下降;在25℃及32℃中,相对湿度对卵的发育速度有明显的影响,随相对湿度的增加,发育加快,二者呈直线正相关。 卵期湿度对一龄幼虫的成活及发育有明显的影响,在32℃中,随着卵期湿度的增加,幼虫成活率提高,二者呈正相关;在25℃及60%以下的相对湿度中,亦获得了相似的结果;25℃及32℃中,一龄幼虫的发育速率与卵期相对湿度呈正相关,随卵期湿度的增加,发育加快。 一龄幼虫期的湿度条件,对一龄幼虫有明显的影响,在25℃中,幼虫的成活率和发育速率与相对湿度均呈正相关,在32℃中,这种影响更为显著,当湿度降低到40%时,全部幼虫均不能存活,在60%以上的相对湿度中,成活率和发育速率均随湿度的提高而增加。