Canine lymphoma-associated antigens defined by murine monoclonal antibodies

Summary Lymphoma in dogs resembles human non-Hodgkin's lymphoma in pathological presentation, immunophenotype, and response to therapy, thus representing a good model for comparative studies with human disease. Monoclonal antibodies (MAbs) were derived from mice immunized with a dog lymphoma cell line. Three MAbs were selected for further application in immunophenotyping and immunotherapy. The binding specificities, antigen characterization, and isotypes for these MAbs are described.Supported by NCI grant CA-10815     

The SV40 TC-II(kappa B) enhanson binds ubiquitous and cell type specifically inducible nuclear proteins from lymphoid and non-lymphoid cell lines.

We have characterized the complexes resulting from the specific binding in vitro of proteins present in nuclear extracts of several lymphoid and non-lymphoid cell lines to the TC-I and TC-II sequences of the simian virus 40 (SV40) enhancer. No proteins could be detected, binding selectively to the TC-I sequence, but two proteins TC-IIA and TC-IIB were identified interacting specifically with both the TC-II/kappa B enhanson, 5'-GGAAAGTCCCC-3' (important for the activity of the SV40 enhancer in vivo), and with the related H-2Kb enhanson, 5'-TGGGGATTCCCCA-3'. The binding of these two proteins to mutated TC-II enhansons correlates with the effect of these mutations in vivo, suggesting that both proteins may be important for SV40 enhancer activity. The TC-IIA binding activity was present in nuclear extracts of mature lymphoid B cells and was increased in pre-B cell nuclear extracts by lipopolysaccharide (LPS) and cycloheximide treatment. Furthermore, complex formation between the TC-IIA protein and the TC-II enhanson was efficiently competed by the kappa B motif from the kappa chain enhancer, indicating that TC-IIA is the NF-kappa B factor or a closely related protein. However, in contrast to previous reports, a TC-IIA/NF-kappa B-like protein whose properties could not be distinguished from those of the TC-IIA protein present in lymphoid B cells, was found in nuclear extracts of several untreated non-lymphoid cell lines, notably of HeLa cells, but not of undifferentiated F9 embryonal carcinoma (EC) cells [F9(ND)]. The TC-IIA binding activity which was moderately increased in HeLa cell nuclear extracts by 12-O-tetradecanoylphorbol-13-acetate (TPA) and/or cycloheximide treatment could be induced in nuclear extracts of F9(ND) cells by cycloheximide, but not by TPA. Moreover, the TC-IIA binding activity could be induced in cytosolic fractions from F9(ND) cells by treatment with deoxycholate, indicating that these cells contain an inhibitor protein similar to the previously described NF-kappa B inhibitor, I kappa B. The second TC-II enhanson binding protein, TC-IIB, which could be clearly distinguished from the TC-IIA/NF-kappa B-like protein, by a number of differential properties, resembles the previously described KBF1/H2TF1 protein as it binds with a higher affinity to the H-2Kb enhanson than to the TC-II/kappa B enhanson, and its pattern of methylation interference on the H-2Kb and TC-II/kappa B enhansons is identical to that reported for the KBF1/H2TF1 protein.(ABSTRACT TRUNCATED AT 400 WORDS)     

The HeLa cell protein TEF-1 binds specifically and cooperatively to two SV40 enhancer motifs of unrelated sequence

We have purified a protein (TEF-1) that specifically binds to two sequence unrelated motifs (GT-IIC and Sph) of the simian virus 40 (SV40) enhancer. TEF-1 binds cooperatively to templates containing tandem but not inverted or spaced repeats of its cognate motifs. This cooperative binding correlates with the ability of the tandem repeats to generate enhancer activity in vivo. In contrast, TEF-1 and a second SV40 enhancer binding protein, TEF-2, bind independently to templates containing the cognate motifs of both proteins (GT-I and either GT-IIC or Sph motifs) even though these motifs cooperate in enhancer activity in vivo. These results allow us to distinguish different classes of enhancer factors.     

Effects of neonatal undernutrition on the electrocortical development of the association areas in the rat

The electrocortical effects provoked by neonatal undernutrition and the environmental sensorial stimuli were studied in the cortical association areas of developing Wistar rats. When the interaction between these two factors was interfered (Experiment 1), the average frequency of the ECoG in the early starved rats was significantly increased than controls. Moreover, if these two factors were combined (Experiment 2) not significant differences in the ECoG average frequencies were observed. The data suggest that the maturation of cells underlying the ECoG in the association areas of the rat, requires not only an adequate supply of nutrients, but also the influence of sensory cues arising from the mother, littermates and the environmental surrounding.     

Identification of some Bacteria from Paddy Antagonistic to Several Rice Fungal Pathogens

The effect of 23 bacterial strains from ricefields in the tropics on rice seed germination and on radicle and hypocotyl development of four rice cultivars was determined. There was a varietal difference in response to seed bacterization with the different bacterial strains. Germination of cv. IR58 increased from 78 to 93 %, that of cv. IR64, from 89 to 97 %. Less effects on germination of cvs IR42 and IR36 were observed. All strains inhibited the mycelial growth of Rhizoctonia solani in vitro. The three strains, identified as Bacillus subtilis, inhibited the mycelial growth of eight fungal pathogens whereas the other strains were pathogen-specific. Seed bacterization with these bacterial strains provided a sheath blight protection of 4. 5 to 73 % in the glasshouse trial. These 23 bacterial strains were identified by phenotypic tests using the API systems, morphological and biochemical features, and by comparison of electrophoretic patterns after sodium dodecyl sulphate polyacrylamide gel electrophoresis. Bacterial strains were identified (number of strains in brackets) as: Bacillus subtilis (3), Bacillus laterosporus (1), Bacillus pumilus (1), Pseudomonas aeruginosa (7), Pseudomonas belonging to section 1 (5), Erwina herbicola-like (1), and Serratia marcescens (1). The features of the other four strains were similar to Serratia except for the DNAase and lipase activities.     

Increased expression of a high molecular weight (130 KD) protein kinase C isoform in a differentiation-defective ras-transfected keratinocyte line

The role of ras on protein kinase C (PKC) signaling was examined in two keratinocyte cell lines. Increasing the level of extracellular calcium from 0.15 mM to 1.0 mM induces some features of differentiation in the spontaneously immortalized HaCaT line, but fails to do so in a c-H-ras-transfected subline (ras-HaCaT). Raising extracellular calcium also induced a transient increase in membrane-associated PKC activity 5 min after calcium addition, in HaCaT, but not in the ras-HaCaT cells. Partial purification of PKC from the membrane/particulate fraction revealed the major isoform expressed in HaCaT to be an 80 KD species recognized by the anti-PKCα antibody. In ras-HaCaT, the major expressed isoform is a 130 KD species recognized by the PKCb? antibody. The kinase activity of the partially purified high molecular weight PKC is phospholipid dependent but calcium independent. Further evaluation of PKC in the HaCaT and ras-HaCaT membrane/particulate cell fraction by immunoblotting using affinity-purified antibodies against PKCα, b?, δ, ε and ζ revealed a 130 KD band reacting with the PKCδ antibody. Increased expression of this high molecular weight protein was observed in ras-HaCaT. Immunoprecipitation of PKC in ras-HaCaT using the PKCδ antibody also revealed a 130 KD species. Analysis of the PKCδ immunoprecipitate demonstrated a phospholipid, but not calcium-dependent kinase which autophosphorylated. These results suggest that the 130 KD protein may be a novel (calcium-independent) PKC (nPKC) isoform and increased expression in the rastransfected HaCaT may be a consequence of oncogenic ras expression. This 130 KD species may also play a role in the ras-associated inhibition of differentiation in HaCaT. © 1995 Wiley-Liss, Inc.     

Trypanosoma evansi kDNA minicircle found in the Venezuelan nectar-feeding bat Leptonycteris curasoae (Glossophaginae), supports the hypothesis of multiple origins of that parasite in South America

Trypanosoma evansi is a mammal generalist protozoon which causes negative effects on health and productivity in bovine and equine herds in South America, Europe, Asia and Africa. By molecular methods, we screened the presence of that parasite together with other trypanosome species in 105 bats of 10 species collected in arid zones of northern Venezuela. The first molecular approach was fluorescent fragment length barcoding (FFLB), which relies on amplification of relative small regions of rRNA genes (four loci) and fluorescence detection. By FFLB, 17 samples showed patterns of possible trypanosomatid infections. These samples were used to test presence of trypanosomes by PCR using the following DNA markers: V7–V8 SSU rRNA, gGAPDH and kDNA minicircle regions. Only in one individual of the nectar-feeding bat, Leptonycteris curasoae, we were able to amplify 1000 bp of the trypanosome kDNA minicircle. That PCR product was sequenced and the parasite species was determined by NCBI-BLAST and phylogenetic analysis. Both analyses showed that the minicircle sequence corresponds to Trypanosoma evansi. The phylogenetic analysis of the sequence obtained in this study clustered with a T. evansi sequence obtained in a Venezuelan capybara, Hydrochoerus hydrochaeris, and distant of others two T. evansi sequences obtained in a Colombian capybara and horse. This result supports the hypothesis of multiple origins of T. evansi in South America.     

Stagnant immigrant social networks and cycles of exploitation

Based on over four years of ethnographic research among street vendors in Los Angeles and on interviews with family members of vendors and former vendors living in Mexico, this article examines the influence of a sending community and its social networks on migrant outcomes in the USA. These social networks affect migration patterns, ease entry into the fruit-vending business but also facilitate exploitation. Furthermore, these social networks do not always function as effective conduits of information because its members, due to feelings of shame or embarrassment, often fail to add to the existing body of knowledge. As a result, international migration patterns, job placement and exploitative practices do not change or improve for subsequent migrants. This creates a cycle in which social networks become stagnant and successively fail to function as effective conduits of information and resources in ways that might help network members equally and in the aggregate.