Expression of mdm-2 oncoprotein in the primary and metastatic sites of mammary tumor (GI-101) implanted athymic nude mice

The expression of mdm-2 oncoprotein (p90) was determined in a human breast tumor xenograft line (GI-101) that was derived from a 57 year old female cancer patient with recurrent, infiltrating ductal adenocarcinoma (Stage IIIa, T3N2MX). Immunoprecipitation coupled western blot analysis of the primary tumors that have been obtained from xenograft implanted athymic nude mice, using mdm-2 (Ab-1) mouse monoclonal antibody, primarily revealed high level expression of a 90 kD full length mdm-2 protein. In the GI-101 tumor the level of full length mdm-2 (p90) protein expression increased with the increase in the size of the tumor (100 to 2,000 mm(3)) and a maximum expression was detected in 2,000 mm(3) size tumors. In addition to the expression in the primary site, a significantly high level expression of mdm-2 protein (p90) was detected in the lung and liver tissues also, which are the known metastatic sites for GI-101 xenograft tumors. However, the level of mdm-2 protein expression was undetectable in the lung and liver tissues obtained from control mice. A cell line (GI-101A) derived from the GI-101 xenograft tumor also showed a high level expression of mdm-2 protein after several generations of cell passage. When the GI-101A cells were treated with DES (Diethylstilbestrol) the mdm-2 protein expression increased after 10 min treatment and reached a peak level at 40 min. Interestingly, DES (10 and 20 microM) treatment increased the total cell number also after 96 hr treatment compared to the non-treated cells. It appears that mdm-2 (p90) may have a significant role in supporting the tumor cell growth as well as the metastatic process of the GI-101A cells.     

Comparative proteomics reveals evidence for evolutionary diversification of rodent seminal fluid and its functional significance in sperm competition

During insemination, males of internally fertilizing speciestransfer a complex array of seminal fluid proteins to the femalereproductive tract. These proteins can have profound effectson female reproductive physiology and behavior and are thoughtto mediate postcopulatory sexual selection and intersexual conflict.Such selection may cause seminal fluid to evolve rapidly, withpotentially important consequences for speciation. Here we investigatethe evolution of seminal fluid proteins in a major mammalianradiation, the muroid rodents, by quantifying diversity in seminalfluid proteome composition for the first time across a broadrange of closely related species. Using comparative proteomicstechniques to identify and cross-match proteins, we demonstratethat rodent seminal fluid is highly diverse at the level ofboth proteomes and individual proteins. The striking interspecificheterogeneity in seminal fluid composition revealed by our surveyfar exceeds that seen in a second proteome of comparable complexity,skeletal muscle, indicating that the complement of proteinsexpressed in seminal fluid may be subject to rapid diversification.We further show that orthologous seminal fluid proteins exhibitsubstantial interspecific variation in molecular mass. Becausethis variation cannot be attributed to differential glycosylationor radical differences in termination sites, it is stronglysuggestive of rapid amino acid divergence. Sperm competitionis implicated in generating such divergence for at least onemajor seminal fluid protein in our study, SVS II, which is responsiblefor copulatory plug formation via transglutaminase-catalyzedcross-linking after insemination. We show that the molecularmass of SVS II is positively correlated with relative testissize across species, which could be explained by selection foran increased number of cross-linking sites involved in the formationof the copulatory plug under sperm competition.     

The protective effect of some food ingredients on Staphylococcus aureus MF31

The upper limiting temperature of growth of Staphylococcus aureus MF31 in heart infusion broth (HI) was about 44°C but addition of monosodium glutamate (MSG) and soy sauce permitted the organism to grow above this temperature. This effect is similar to that of NaCl. Tomato ketchup, Worcestershire and HP sauces added to HI did not allow growth at the non-permissive temperature of 46°C but death was delayed. Staphylococcus aureus died in unsupplemented chicken meat slurry at 46°C but grew at 48°C in slurry supplemented with 5.8% NaCl and survived incubation for 18 h at 50°C in slurry supplemented with 5.8% NaCl and 5% MSG. Cultures grown at 37°C had a D ₆₀ value of 2 min in 50 mmol/l Tris (pH 7.2) buffer. Cultures grown at 46°C in HI containing 5.8% NaCl had a D ₆₀ value of 8 min in Tris buffer. Addition of 5.8% NaCl plus 5% MSG to the buffer increased the D ₆₀ by a factor of about 7 for both cultures. In storage experiments at room temperature, the culture grown at 37°C and at 46°C plus 5.8% NaCl died at about the same rate in salami. In milk powder, however, the count of 37°C culture decreased from 10⁹/g to 10⁶/g in 5 weeks while the count of 46°C culture remained unchanged. In cottage cheese, freeze-dried rice and macaroni, the 37°C cultures also died more rapidly. It is suggested that cultures grown at 46°C plus 5.8% NaCl may be suitable for experiments with artificially contaminated foods.     

Toxic heavy metal ions activate the heme-regulated eukaryotic initiation factor-2 alpha kinase by inhibiting the capacity of hemin-supplemented reticulocyte lysates to reduce disulfide bonds.

Addition of toxic heavy metal ions (Cd2+, Hg2+, and Pb2+) to hemin-supplemented rabbit reticulocyte lysate brings about the activation of the heme-regulated eukaryotic initiation factor 2 alpha kinase (HRI) and the inhibition of protein chain initiation. In this report we examined the effects of monothiol and dithiol compounds, metal ion-chelating agents, and metallothioneins (MT) on metal ion-induced inhibition of protein synthesis. The dithiol compounds dithiothreitol and 2,3-dimercaptopropane sulfonic acid prevented and relieved the inhibition of protein synthesis caused by Cd2+ and Hg2+ in hemin-supplemented lysates, but the monothiol compounds 2-mercaptoethanol, cysteamine, D-(-)penicillamine, and glutathione had no effect. The inhibition of protein synthesis caused by Cd2+ was reversed by the addition of excess EDTA but not by the addition of excess nitrilotriacetic acid. Toxic heavy metal ions inhibited the capacity of hemin-supplemented lysate to reduce disulfide bonds. Addition of excess EDTA to Cd(2+)-inhibited lysates restored the capacity of the lysate to reduce disulfide bonds and inhibited the phosphorylation of eukaryotic initiation factor eIF-2. MTs and their apoproteins (apoMTs) inhibited the activation of HRI and protected protein synthesis from inhibition by Cd2+, Hg2+, and Pb2+. Addition of apoMTs to heavy metal ion-inhibited lysates restored the capacity of lysates to reduce disulfide bonds. The restoration of the lysate's thioredoxin/thioredoxin reductase activity was accompanied by the inactivation of HRI and the resumption of protein synthesis, indicating that apoMTs can "detoxify" metal ions already bound to proteins. Several observations presented in this report suggest that the binding of metal ions to the alpha-domain of MT is responsible for the ability of MT to sequester bound metal in a non-toxic form. Addition of glucose 6-phosphate or NADPH had no effect on protein synthesis in metal ion-inhibited lysates, and NADPH concentrations in Cd(2+)-inhibited and hemin-supplemented control lysates were equivalent. The data suggest that the metal ions cause the inhibition of protein synthesis by binding to vicinal sulfhydryl groups present in some critical protein(s), possibly the dithiols present in the active site of thioredoxin and (or) thioredoxin reductase, which leads to the activation of HRI.     

Effects of the lipid peroxidation product 4-hydroxynonenal on the aggregation of human platelets

The stimulation by ADP or arachidonic acid of the aggregation of human platelets in plasma was inhibited by 4-hydroxynonenal (HNE). This reduction of aggregation was time related, and was increased by prolonged preincubation of the platelets with the aldehyde. HNE was more potent than its homologue 4-hydroxypentenal (HPE). HNE was less active in decreasing the aggregation induced by calcium ionophore A23187 or collagen in comparison with ADP. HNE was inactive against aggregation of platelet-rich plasma (PRP) stimulated by thrombin whereas it potently inhibited the aggregation of washed platelets in response to both thrombin and collagen. Platelets were found to degrade HNE, and mechanisms additional to covalent binding to glutathione are indicated by the results obtained. The aldehydes, including HNE, generated by platelets originated principally from arachidonic acid metabolism.     

Can maternally inherited endosymbionts adapt to a novel host? Direct costs of Spiroplasma infection,but not vertical transmission efficiency,evolve rapidly after horizontal transfer into D. melanogaster

Maternally inherited symbionts are common in arthropods and many have important roles in host adaptation. The observation that specific symbiont lineages infect distantly related host species implies new interactions are commonly established by lateral transfer events. However, studies have shown that symbionts often perform poorly in novel hosts. We hypothesized selection on the symbiont may be sufficiently rapid that poor performance in a novel host environment is rapidly ameliorated, permitting symbiont maintenance. Here, we test this prediction for a Spiroplasma strain transinfected into the novel host Drosophila melanogaster. In the generations immediately following transinfection, the symbiont had low transmission efficiency to offspring and imposed severe fitness costs on its host. We observed that effects on host fitness evolved rapidly, being undetectable after 17 generations in the novel host, whereas vertical transmission efficiency was poorly responsive over this period. Our results suggest that long-term symbiosis may more readily be established in cases where symbionts perform poorly in just one aspect of symbiosis.     

Fleshing Out Vulnerability

In the literature on medical ethics, it is generally admitted that vulnerable persons or groups deserve special attention, care or protection. One can define vulnerable persons as those having a greater likelihood of being wronged – that is, of being denied adequate satisfaction of certain legitimate claims. The conjunction of these two points entails what we call the Special Protection Thesis. It asserts that persons with a greater likelihood of being denied adequate satisfaction of their legitimate claims deserve special attention, care or protection. Such a thesis remains vague, however, as long as we do not know what legitimate claims are. This article aims at dispelling this vagueness by exploring what claims we have in relation to health care – thus fleshing out a claim‐based conception of vulnerability. We argue that the Special Protection Thesis must be enriched as follows: If individual or group X has a greater likelihood of being denied adequate satisfaction of some of their legitimate claims to (i) physical integrity, (ii) autonomy, (iii) freedom, (iv) social provision, (v) impartial quality of government, (vi) social bases of self‐respect or (vii) communal belonging, then X deserves special attention, care or protection. With this improved understanding of vulnerability, vulnerability talk in healthcare ethics can escape vagueness and serve as an adequate basis for practice.     

Production of Diamino propionic acid ammonia lyase by a new strain of Salmonella typhimurium PU011

Background  

Seeds of the legume plant Lathyrus sativus, which is grown in arid and semi arid tropical regions, contain Diamino Propionic acid (DAP). DAP is a neurotoxin, which, when consumed, causes a disease called Lathyrism. Lathryrism may manifest as Neurolathyrism or Osteolathyrism, in which the nervous system, and bone formation respectively, are affected. DAP ammonia lyase is produced by a few microorganisms such as Salmonella typhi, Salmonella typhimurium and Pseudomonas, and is capable of detoxifying DAP.     

Differential Effect of Tetrazolium Dyes upon Bacteriophage Plaque Assay Titers

This study examined whether the practice of incorporating either tetrazolium red or tetrazolium violet dye into plaque assay medium deleteriously influences plaque assay titers. Representative members of six different virus families were studied: Cystoviridae (ϕ6), Leviviridae (MS2), Microviridae (ϕX174), Myoviridae (T2), Podoviridae (P22), and Siphoviridae (Denver, T1, and VD13). Each of the members of the Podoviridae and Siphoviridae families appeared to be suppressed by either one or both dyes at a 300-μg/ml concentration. The chosen representatives of the other bacteriophage families were not suppressed by either dye at a 300-μg/ml concentration. Subsequent trials revealed no suppression of Podoviridae or Siphoviridae plaque assay titers when members of these virus families were tested with the same two dyes at the lower concentrations of 150 and 50 μg/ml. Interestingly, the bacteriophage families whose members were affected by the dyes have additional commonality in that they are the two bacteriophage families whose members possess both double-stranded DNA genomes and noncontractile tails.