The pharmacological characterization of 5-HT3 receptor binding sites in rabbit ileum: Comparison with those in rat ileum and rat brain

We have further characterized the 5-HT₃ receptors in rat and rabbit tissues by evaluating the binding of the 5-HT₃ receptor ligand, [³H]GR67330 to homogenates of rabbit ileum, rat ileum and rat brain (entorhinal cortex). In each tissue specific [³H]GR67330 binding represented a single saturable, high affinity site (K_d = 0.14, 0.18, 0.076 nM in rabbit ileum, rat ileum and rat brain respectively). The densities of sites present in rabbit and rat ileum were similar to that present in rat brain (B_max = 63, 47, 72 fmol/mg protein in rabbit ileum, rat ileum and rat brain respectively).

In each tissue, 5-HT₃ receptor agonists and antagonists potently competed for [³H]GR67330 binding. Derived inhibition constants were similar in rat ileum and brain. However marked differences in IC₅₀s were apparent for rabbit ileum compared with rat brain or ileum. These were most apparent with agonists. Thus, mCPBG [1-(meta-chlorophenylbiguanide)], phenylbiguanide, 5-HT and 2-methyl 5-HT were at least 5 times less potent to inhibit [³H]GR67330 binding in rabbit ileum than rat brain. The most pronounced differences were evident with phenylbiguanide and mCPBG which were 70 and 300 times less potent in the rabbit ileum respectively compared with the rat tissues. These differences were unlikely to be due to depletion effects because tissue combination experiments (rabbit ileum and rat brain) yielded biphasic inhibition curves for phenylbiguanide with affinities for each component similar to those in the individual tissues. Antagonist affinities also varied between the rabbit and rat tissues, although less markedly. Amongst the antagonists, the most marked differences were apparent with SDZ 206–830 and quipazine each being 10 times less potent to inhibit binding to rabbit than rat tissue.

Hill coefficients for inhibition of binding varied with tissue. In rat brain, as previously described for [³H]GR67330, Hill coefficients for agonist (and quipazine) inhibition of binding were greater than unity. This was less marked in rat and rabbit ileum tissues.

The present studies provide further evidence for species variation in 5-HT₃ receptors.     

Human and mouse S-protein mRNA detected in Northern blot experiments and evidence for the gene encoding S-protein in mammals by Southern blot analysis

Summary Human S-protein is a serum glycoprotein that binds and inhibits the activated complement complex, mediates coagulation through interaction with antithrombin III and plasminogen activator inhibitor I, and also functions as a cell adhesion protein through interactions with extracellular matrix and cell plasma membranes. A full length cDNA clone for human S-protein was isolated from a lambda gt11 cDNA library of mRNA from the HepG2 hepatocellular carcinoma cell line using mixed oligonucleotide sequences predicted from the amino-terminal amino acid sequence of human S-protein. The cDNA clone in lambda was subcloned into pUC18 for Southern and Northern blot experiments. Hybridization with radiolabeled human S-protein cDNA revealed a single copy gene encoding S-protein in human and mouse genomic DNA. In addition, the S-protein gene was detected in monkey, rat, dog, cow and rabbit genomic DNA. A 1.7 Kb mRNA for S-protein was detected in RNA from human liver and from the PLC/PRF5 human hepatoma cell line. No S-protein mRNA was detected in mRNA from human lung, placenta, or leukocytes or in total RNA from cultured human embryonal rhabdomyosarcoma (RD cell line) or cultured human fibroblasts from embryonic lung (IMR90 cell line) and neonatal foreskin. A 1.6 Kb mRNA for S-protein was detected in mRNA from mouse liver and brain. No S-protein mRNA was detected in mRNA from mouse skeletal muscle, kidney, heart or testis.     

Differential cytotoxicity and mycotoxin content among isolates of Fusarium moniliforme

Curvularia lunata was found causing (disseminated phaeohyphomycosis among a group of Nezara viridula (Insecta:Heteroptera) parasitizing vegetable crop Vigna unguiculata. Dark lesions were seen on pronotum and abdominal sterna. Experimental lesions were produced by applying 0.1 ml of 6.2 × 10⁸cfu/ml^–1 on abdominal sterna. Histopathology revealed that almost all internal organs and tissues showed extensive damage. It is interesting to note that C. lunata exhibited predeliction for chitinous tissues and elicited cellular immune response by granulocytes (phagocytosis). This is the first report of phaeohyphomycosis of an insect, extending the disease to invertebrates.A promising research career of one of the authors (Mrs. Vinita Dubey) was cut short by untimely death. This paper is dedicated to her memory.     

Acclimatory responses in enzymatic activity and metabolite concentrations in the tropical scorpion Heterometrus fulvipes

1. 1.|Changes in tissue metabolite concentrations and enzyme activities in the pedipalpal (PM) and heart (HM) muscles of the tropical scorpion Heterometrus fulvipes show that the metabolism in PM and HM is fundamentally reorganized following low (18°C) and high (38°C) temperature acclimation.

2. 2.|Changes in metabolite concentrations show that metabolite biosynthesis showed increases after cold acclimation but decreases after warm acclimation.

3. 3.|Similarly, changes in enzyme activities show a preponderance of glycolysis and HMP shunt activity after cold acclimation, while after warm acclimation glycogenolysis, oxidative metabolism and gluconeogenesis predominated.

4. 4.|Higher metabolite concentrations and enzyme activities both before and after thermal acclimation in HM reflect its greater compensatory abilities.

Effects of cytokines on in vitro growth of tumor-infiltrating lymphocytes obtained from human primary and metastatic liver tumors

Summary Tumor-infiltrating lymphocytes (TIL) were isolated from 22 human primary and metastatic liver tumors, and expanded in vitro in the presence of either interleukin-2 (IL-2, 100 U/ml) plus tumor necrosis factor (TNF, 1000 U/ml), IL-2 (1000 U/ml) plus IL-4 (1000 U/ml) or IL-2 (1000 U/ml) alone. TIL proliferated in culture in 20/22 cases. Among different cytokine combinations, TNF and IL-2 were most effective in promoting the outgrowth of CD3⁺ CD8⁺ T lymphocytes (mean ± SEM: 90%±5) in the cultures of TIL from primary liver tumors. Cytotoxicity against autologous tumor cells was demonstrated in all early cultures of TIL from primary liver cancers in the presence of IL-2 plus TNF. In contrast, cultures of TIL derived from colon cancer metastatic to liver had significantly lower levels of autotumor cytotoxicity and proportions of CD3⁺ CD8⁺ cells (40%±13) than those of TIL from primary liver tumors. The addition on day 0 of interferons ( or ) to TIL cultured in the presence of TNF and IL-2, significantly augmented cytotoxicity against autologous tumor. In contrast, incubation of TIL in the presence of IL-4 and IL-2 did not result in increased autotumor responses in the cultures of TIL from primary liver tumors. The expansion (-fold) of TIL (day 30) cultured in the presence of IL-2 alone compared to that in the presence of TNF and IL-2 was significantly greater for hepatocellular carcinoma (median, 280 vs 260) than for autologous peripheral blood lymphocytes (36 vs 27), cholangiocarcinoma (42 vs 51) or TIL from metastatic colon cancer (39 vs 30). Outgrowth of TIL in IL-2 plus TNF offers an opportunity for in vitro enrichment in cells with autotumor cytotoxicity in primary liver tumors. However, this cytokine combination was unable to promote and sustain growth of autotumor effectors from TIL in metastatic liver cancer.Supported by ACS grants IM27 077 and IM588 A (TLW) and Organ Transplant Program Project 1P01-CA-4744501 AZ     

Effect of introducing genetically engineered microorganisms on soil microbial community diversity

Abstract Introducing the genetically engineered microorganism Pseudomonas cepacia AC1100 into soil microcosms resulted in elevated taxonomic diversity determined by phenotypic analyses of culturable isolates and genetic diversity determined by analysis of the heterogeneity of total microbial community DNA reannealing kinetics. The greatest impact occurred when P. cepacia AC1100 was introduced along with the herbicide 2,4,5-T, which P. cepacia AC1100 can degrade. The data suggests that both changes in the balance of populations and genetic recombination contributed to the increased diversity.     

The localisation of an Mr 74,000 major chromatin antigen on native salivary chromosomes of Drosophila melanogaster

An antigen making a major contribution to the immune response to Drosophila melanogaster chromatin resides primarily on a nonhistone charge-class family of proteins of Mr 74,000. Immunofluorescence detects this antigen at interbands, puffs and diffuse bands of D. melanogaster salivary chromosomes isolated without exposure to acid fixatives, and on nucleoplasmic ribonucleoprotein droplets. In the electron microscope, gold labelling reveals the binding of monoclonal antibodies specific for the antigen at chromosomal loci generally bearing putative ribonucleoprotein (RNP) particles. However, the locus 3C 11–12 is remarkable in that it bears putative RNP particles but is virtually unlabelled, suggesting protein specificity at different active loci.     

Taxonomic studies on marine triclads (Turbellaria,Tricladida, Maricola)

The genus Procerodes forms a heterogeneous assemblage of taxa. Although it is premature to attempt phylogenetic weighting of the characters, the genus contains three well delimited subgroups, one with a subantarctic, panaustral distribution, one world-wide in distribution, and one occurring principally in the northern hemisphere. Outside of these subgroups, species in this genus are problematic since a number of their features also occurs in other procerodids. All recognized groups exhibit a wide distributional range. Many of the world-wide taxonomic relations lie on the species level and some at the level of genera. Poor dispersal capacity of extant species of Procerodes suggests that the biogeographic patterns may be very old.     

Movements of some indigenous riverine fish in Sri Lanka

The migratory movements of reproductive potamodromus fish established in man-made tropical lakes in the dry zone of Sri Lanka were determined. It was shown that the nine indigenous riverine species do not spawn in these lakes but move into the upstream channels when sexually mature. The pattern of upstream movement was found to be species-specific although most species showed a diurnal periodicity. It is suggested that the development of totally lacustrine forms of riverine species is very unlikely to occur in the man-made lakes of Sri Lanka because of their relatively short duration time.