Alkaloids of the leaves of Voacanga grandifolia

Besides vobtusine and vobtusine-lactone, deoxyvobtusine was isolated from the leaves of Voacanga grandifolia (Miq. Rolfe. Spectral and chemical evi     

Antimicrobial activity and cytotoxicity trait of a bioactive peptide purified from Lactococcus garvieae subsp. bovis BSN307T

A bioactive peptide of 8595 Da was purified from the cell free supernatant of Lactococcus garvieae subsp. bovis BSN307^T. MALDI MS/MS peptide mapping and the data base search displayed no significant similarity to any reported antimicrobial peptide of LAB. This peptide at a dose concentration of 200 µg ml⁻¹ inhibited the growth of both Gram-positive and Gram-negative bacteria by 58–89% and a dose of 500 µg ml⁻¹ scavenged 50% of DPPH-free radicals generated. Interestingly, cytotoxicity assay demonstrated that 17 µg ml⁻¹ of peptide selectively inhibited 50% proliferation of mammalian cancer cell lines HeLa and MCF-7 whereas normal H9c2 cells remained unaffected. Fluorescent microscopic analysis after DAPI nuclear staining of HeLa cells showed characteristics of apoptosis and activation of caspase-3 was ascertained by caspase-3 fluorescence assay.     

Mesothelioma Tumor Cells Modulate Dendritic Cell Lipid Content,Phenotype and Function

Dendritic cells (DCs) play an important role in the generation of anti-cancer immune responses, however there is evidence that DCs in cancer patients are dysfunctional. Lipid accumulation driven by tumor-derived factors has recently been shown to contribute to DC dysfunction in several human cancers, but has not yet been examined in mesothelioma. This study investigated if mesothelioma tumor cells and/or their secreted factors promote increases in DC lipid content and modulate DC function. Human monocyte-derived DCs (MoDCs) were exposed to human mesothelioma tumor cells and tumor-derived factors in the presence or absence of lipoproteins. The data showed that immature MoDCs exposed to mesothelioma cells or factors contained increased lipid levels relative to control DCs. Lipid accumulation was associated with reduced antigen processing ability (measured using a DQ OVA assay), upregulation of the co-stimulatory molecule, CD86, and production of the tolerogenic cytokine, IL-10. Increases in DC lipid content were further enhanced by co-exposure to mesothelioma-derived factors and triglyceride-rich lipoproteins, but not low-density lipoproteins. In vivo studies using a murine mesothelioma model showed that the lipid content of tumor-infiltrating CD4⁺CD8α^- DCs, CD4^-CD8α^- DCs DCs and plasmacytoid DCs increased with tumor progression. Moreover, increasing tumor burden was associated with reduced proliferation of tumor-antigen-specific CD8⁺ T cells in tumor-draining lymph nodes. This study shows that mesothelioma promotes DC lipid acquisition, which is associated with altered activation status and reduced capacity to process and present antigens, which may impair the ability of DCs to generate effective anti mesothelioma T cell responses.     

Effect of orally-administered epidermal growth factor on intestinal iron absorption and mucosal permeability

A progressive increase in intestinal 59Fe3+ absorption was observed on oral feeding of mice with physiological doses of EGF/UGO. Maximal changes were apparent after 3d and appeared to be dose-dependent. In addition to a small increase in intestinal cell proliferation, as reflected by increased ornithine decarboxylase activity, EGF/UGO-feeding increased mucosal permeability (evaluated with [51Cr]-EDTA): the latter could account for the increase in iron absorption. Sialoadenectomy, to remove the major source of endogenous EGF/UGO, had no appreciable effect on the intestinal absorption of iron.     

A minority of 46,XX true hermaphrodites are positive for the Y-DNA sequence including SRY

Summary A total of 30 cases of 46,XX true hermaphroditism was analysed for Y-DNA sequences including the recently cloned gene for male testis-determination SRY. In 3 cases, a portion of the Y chromosome including SRY was present and, in 2 cases, was localised, to Xp22 by in situ hybridisation. Since previous studies have shown that the majority of XX males are generated by an X-Y chromosomal interchange, the Xp22 position of the Yp material suggests that certain cases of hermaphroditism can arise by the same meiotic event. The phenotype in the 3 SRY-positive cases may be caused by X-inactivation resulting in somatic mosaicism of testis-determining factor expression giving rise to both testicular and ovarian tissues. Autosomal or X-linked mutation(s) elsewhere in the sex-determining pathway may explain the phenotype observed in the remaining 27 SRY-negative cases.     

Specific intracellular hyaluronic acid binding to isolated rat hepatocytes is membrane-associated

Intact isolated rat hepatocytes show a small amount of specific 125I-labeled hyaluronic acid (HA) binding. However, in the presence of digitonin, a very large increase in the specific binding of 125I-HA is observed. Chondroitin sulfate, heparin and dextran sulfate were as effective as unlabeled HA in competing for 125I-HA binding to permeabilized hepatocytes, indicating that the binding sites may have a general specificity for glycosaminoglycans. After rat hepatocytes had been homogenized in a hypotonic buffer, more than 98% of the 125I-HA binding activity could be pelleted by centrifugation at 100,000 x g for 1 h. Mild alkaline treatment of hepatocyte membranes did not release 125I-HA binding activity, suggesting that the HA binding site is an integral membrane molecule. Furthermore, trypsin treatment of deoxycholate-extracted membranes destroyed the binding activity, as assessed by a dot-blot assay. This suggests that a protein component in the membrane is necessary for 125I-HA binding activity. Rat fibrinogen could be a possible candidate for the HA binding activity because HA binds specifically to human fibrinogen (LeBoeuf et al. (1986) J. Biol. Chem. 261, 12 586). Also, fibrinogen can be found in a quasi-crystalline form in rat hepatocytes and could be pelleted with the membranes. Rat fibrinogen was not responsible for the 125I-HA binding activity, since (1) purified rat fibrinogen did not bind to 125I-HA, and (2) immunoprecipitation of rat fibrinogen from hepatocyte extracts did not decrease the 125I-HA binding of these extracts. We conclude that the internal HA binding sites are membrane- or cytoskeleton-associated proteins and are neither cytosolic proteins nor fibrinogen.     

Studies on the role of transferrin and endocytosis in the uptake of Fe3+ from Fe-nitrilotriacetate by mouse duodenum

Addition of iron-binding proteins (human serum transferrin, mouse serum transferrin, human lactoferrin) to the luminal fluid in tied-off segments of mouse intestine in vivo led to reduced 59Fe3+ absorption from 59Fe3+-nitrilotriacetate when compared to 59Fe3+-nitrilotriacetate alone. Assay of transferrin in luminal fluid from tied segments revealed only trace amounts of immunoreactivity. The levels of luminal transferrin are unaltered in chronic hypoxia where iron absorption is significantly enhanced. Studies in vitro revealed that NH4Cl, dansylcadavarine, para-chloromercuribenzoate and trinitrobenzenesulphonate have no effect on initial 59Fe3+ uptake rates from 59Fe3+-nitrilotriacetate, while N-ethylmaleimide (1 mM) caused a 40% inhibition. In vivo 59Fe3+ uptake was unaffected by preincubation of tied-off segments with colchicine (5 mM) for up to 2 h. These results suggest that receptor-mediated endocytosis of transferrin is not a significant mechanism in the uptake of luminal Fe3+ by mouse duodenum.     

Determinants of fruit and seed set in Pavonia dasypetala (Malvaceae)

Summary Measurements of foliage quality, physiological, and phenological condition of sample trees were used as independent variables in multiple correlation analyses to determine their effect on female and male spruce budworm larval dry weights. Female budworm from trees high in foliar concentrations of beta-pinene, myrcene and total nitrogen weighed less than those from trees lacking these characteristics. Male budworm from trees high in foliar concentrations of alpha-pinene, myrcene, terpinolene, citronellyl acetate, and bornyl acetate weighted less than those from trees lacking these characteristics. Additionally, relatively vigorous and productive trees tended to be less susceptible (as evidenced by reduced larval weight) to budworm of either sex.