Classification of cell types: Agglutination and chromosomal properties

Summary The properties of agglutination by plant lectins, along with chromosome patterns, were examined in a variety of mammalian cell types. Untransformed adult and embryonic cells in culture, direct mouse spleen cell preparations, SV40-transformed 3T3 cells, and trypsinized 3T3 cells were all highly agglutinable with concanavalin A and with wheat germ agglutinin. In contrast, untreated cells of the contact-inhibited 3T3 line were alone among the cells tested in their low agglutinability. Chromosome analysis of the cultured cells showed that karyotypic variation from the diploid to an aneuploid state in mouse and rat embryo cultures was not accompanied by a change in agglutinability. Adult rat lung, adult monkey kidney, and embryonic human lung cells, which were all highly agglutinable, showed the normal diploid pattern. Thus, agglutination of cells by plant lectins appears to be a cellular property often associated with non-neo-plastic cells. This investigation was supported by Grants CA-12503 and ES-00260 from the National Institutes of Health, United States Public Health Service.     

Substance P affects the GABAergic system in the hypothalamo-pituitary axis

In the present work we examined the effect of the neutralization of endogenous substance P by the administration of an anti-substance P serum (ASPS) on GABA concentration in the anterior pituitary in hyperprolactinemic conditions induced by 5-hydroxytryptophan or by grafting anterior pituitaries. ASPS reduced the increase in the anterior pituitary GABA concentration induced by hyperprolactinemia. In vitro experiments showed that substance P inhibited K⁺-evoked GABA efflux from hypothalamic fragments and decreased GABA concentration in the anterior pituitary but ASPS increased it. Our results demonstrate that substance P modifies hypothalamic GABA release and anterior pituitary GABA concentration and suggest that an interaction exists between substance P and GABA.     

Increased Neostriatal Tyrosine Hydroxylation During Stress: Role of Extracellular Dopamine and Excitatory Amino Acids

Abstract: We examined the regulation of neostriatal tyrosine hydroxylation during acute stress, testing the hypothesis that excitatory amino acids (EAAs) contribute to the stress-evoked increase in dopamine (DA) synthesis. Dialysis probes implanted into neostriatum permitted delivery of drugs and sampling of extracellular fluid. Rats were exposed to 30 min of intermittent tail shock during infusion of an inhibitor of aromatic amino acid decarboxylase (AAAD), NSD-1015 (100 µM), and DOPA was measured in the dialysate. Tail shock was applied beginning either 15 min after the onset of NSD-1015 treatment (the initial rate of DOPA accumulation) or 75 min after the onset of treatment (when DOPA had approached steady state). Tail shock increased the steady-state levels of extracellular DOPA in neostriatum (+40%). However, there was no change in the initial rate of DOPA accumulation unless animals also received the D₂ receptor antagonist eticlopride (50 nM), in which case an increase was observed (+228%). The impact of tail shock on the steady-state level of DOPA was attenuated by the D₂ agonist quinpirole (100 µM), or by 2-amino-5-phosphonovalerate (APV) (100 µM) or 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) (100 µM), EAA antagonists acting at NMDA or d ,l -α-amino-3-hydroxy-5-methyl-4-isoxazole-4-propionate (AMPA) receptors, respectively. These data suggest that acute stress normally has little effect on tyrosine hydroxylation in neostriatum due to the inhibitory influence of DA in the extracellular fluid. However, when that influence is absent (e.g., during extended inhibition of DOPA decarboxylation or blockade of DA receptors), stress increases tyrosine hydroxylation via EAAs acting on NMDA and AMPA receptors. Thus, EAAs released from corticostriatal projections may stimulate DA synthesis and thereby restore dopaminergic activity under conditions in which the availability of DA for release has been compromised.     

Detection of Obesity QTLs on Mouse Chromosomes 1 and 7 by Selective DNA Pooling

The inheritance of obesity has been analyzed in an intercross between the lean 129/Sv mouse strain and the obesity-prone EL/Suz mouse strain. The weights of three major fat pads were determined on 4-month-old mice, and the sum of these weights, divided by body weight, was used as an adiposity index. The strategy of selective DNA pooling was used as a primary screen to identify putative quantitative trait loci (QTLs) affecting adiposity index. DNA pools representing the leanest 15% and fattest 15% of the F2 progeny were compared for differential allelic enrichment using widely dispersed microsatellite variants. To evaluate putative QTLs, individual genotyping and interval mapping were employed to estimate QTL effects and assess statistical significance. One QTL affecting adiposity index, which accounted for 12.3% of phenotypic variance in gender-merged data, was mapped to the central region of Chromosome (Chr) 7. The QTL allele inherited from EL conferred increased adiposity. A second QTL that accounts for 6.3% of phenotypic variance was identified on Chr 1 nearD1Mit211.At both QTLs, the data are consistent with dominant inheritance of the allele contributing to obesity. The possible relationships between these QTLs and previously described obesity QTLs, major obesity mutations, and candidate genes are discussed.     

Biochemical properties of a novel cell wall protein associated with elongation growth in higher plants

A monoclonal antibody of IgM-type (TIM-11B2) was screened froma hybridoma library. The antibody recognizes a 40 kDa glycoprotein,p40, with high specificity. This protein was detected in allplant species examined so far and was found to be located bothsolubly and ionically-bound within the primary cell wall. The strongest immunobiochemical signals of p40 were found intissues undergoing elongation growth, whereas in other tissuesonly a faint signal could be detected. Those included the non-elongatingparts of different seedlings, such as the apical part of monocotprimary leaves or the leaves of dicots grown in light. Inhibitionof pea epicotyl growth by white light irradiation resulted ina strong decrease of the immunostain signal. On the other hand,induction of rapid coleoptile growth in rice seedlings inducedby submergence resulted in a strong increase of the immunobiochemicalsignal of p40. Time-course studies on the expression of p40during protoplast regeneration revealed that p40 is apparentlynot involved in cell wall formation. The hypothesis that p40is characteristic for tissues with the ability for elongationgrowth is discussed. Comparison of biochemical data and location of p40 with proteinsdescribed up to now indicate that this glycoprotein has notbeen characterized before. Key words: Cell wall protein, elongation growth, monoclonal antibody     

Sequence analysis of cohesive ends of the actinophage RP3 genome and construction of a transducible shuttle vector

Abstract The sequence of the cohesive ends of actinophage RP3 DNA has been determined. As with all other phages of Gram-positive bacteria that have been studied sofar, RP3 DNA has 3'-protruding ends. A shuttle cosmid has been constructed containing this cos area which can be efficiently transduced by phage RP3 to host cells of Streptomyces rimosus .     

Octopamine receptor subtypes and their modes of action

Octopamine receptor subclasses were first proposed to explain differences in the pharmacological profiles of a range of physiological responses to octopamine obtained in the extensor-tibiae neuromuscular preparation of the locust. Thus, OCTOPAMINE₁ receptors which inhibit an endogenous myogenic rhythm, increase intracellular calcium levels. Also OCTOPAMINE₂ receptors which modulate neuromuscular transmission in this preparation, increase the level of adenylate cyclase activity. The current status of this classification is reviewed by examining the pharmacology of responses to octopamine in a range of preparations. It is concluded that the distinction between OCTOPAMINE₁ and OCTOPAMINE₂ receptor types is still valid, but that OCTOPAMINE₂ receptors exhibit some tissue specific variations. Studies on a clonedDrosophila octopamine/tyramine (phenolamine) receptor are discussed and illustrate many of the difficulties presently encountered in making a definitive classification of octopamine receptors. These include the possibilities that single receptors may activate multiple second messenger systems and that different agonists may differentially couple the same receptor to different second messenger systems.     

Excretion of proline bySaccharomyces cerevisiae during fermentation of arginine-supplemented high gravity wheat mash

Summary The rate of ethanolic fermentation of high gravity wheat mashes bySaccharomyces cerevisiae was increased by nitrogen sources such as ammonium sulfate or arginine. This stimulation was mediated through increased proliferation of cells. Large quantities of proline, however, were excreted by the yeast into the medium when arginine was added as a nutrient supplement. The amount of proline excreted was proportional to the concentration of arginine supplied. Nitrogen sources such as ammonium sulfate or lysine enhanced the production of proline from arginine and its excretion into the medium. Results show that the stimulation of very high gravity fermentation by arginine is not merely through provision of a source of nitrogen but also because it serves as a precursor for the production of proline, a compound which may play a significant role in alleviating the effects of osmotic stress.     

The distribution of coastal fish eDNA sequences in the Anthropocene

Aim

Coastal fishes have a fundamental role in marine ecosystem functioning and contributions to people, but face increasing threats due to climate change, habitat degradation and overexploitation. The extent to which human pressures are impacting coastal fish biodiversity in comparison with geographic and environmental factors at large spatial scale is still under scrutiny. Here, we took advantage of environmental DNA (eDNA) metabarcoding to investigate the relationship between fish biodiversity, including taxonomic and genetic components, and environmental but also socio-economic factors.

Location

Tropical, temperate and polar coastal areas.

Time period

Present day.

Major taxa studied

Marine fishes.

Methods

We analysed fish eDNA in 263 stations (samples) in 68 sites distributed across polar, temperate and tropical regions. We modelled the effect of environmental, geographic and socio-economic factors on α- and β-diversity. We then computed the partial effect of each factor on several fish biodiversity components using taxonomic molecular units (MOTU) and genetic sequences. We also investigated the relationship between fish genetic α- and β-diversity measured from our barcodes, and phylogenetic but also functional diversity.

Results

We show that fish eDNA MOTU and sequence α- and β-diversity have the strongest correlation with environmental factors on coastal ecosystems worldwide. However, our models also reveal a negative correlation between biodiversity and human dependence on marine ecosystems. In areas with high dependence, diversity of all fish, cryptobenthic fish and large fish MOTUs declined steeply. Finally, we show that a sequence diversity index, accounting for genetic distance between pairs of MOTUs, within and between communities, is a reliable proxy of phylogenetic and functional diversity.

Main conclusions

Together, our results demonstrate that short eDNA sequences can be used to assess climate and direct human impacts on marine biodiversity at large scale in the Anthropocene and can further be extended to investigate biodiversity in its phylogenetic and functional dimensions.