Assessing the ecological risks from the persistence and spread of feral populations of insect-resistant transgenic maize

One source of potential harm from the cultivation of transgenic crops is their dispersal, persistence and spread in non-agricultural land. Ecological damage may result from such spread if the abundance of valued species is reduced. The ability of a plant to spread in non-agricultural habitats is called its invasiveness potential. The risks posed by the invasiveness potential of transgenic crops are assessed by comparing in agronomic field trials the phenotypes of the crops with the phenotypes of genetically similar non-transgenic crops known to have low invasiveness potential. If the transgenic and non-transgenic crops are similar in traits believed to control invasiveness potential, it may be concluded that the transgenic crop has low invasiveness potential and poses negligible ecological risk via persistence and spread in non-agricultural habitats. If the phenotype of the transgenic crop is outside the range of the non-transgenic comparators for the traits controlling invasiveness potential, or if the comparative approach is regarded as inadequate for reasons of risk perception or risk communication, experiments that simulate the dispersal of the crop into non-agricultural habitats may be necessary. We describe such an experiment for several commercial insect-resistant transgenic maize events in conditions similar to those found in maize-growing regions of Mexico. As expected from comparative risk assessments, the transgenic maize was found to behave similarly to non-transgenic maize and to be non-invasive. The value of this experiment in assessing and communicating the negligible ecological risk posed by the low invasiveness potential of insect-resistant transgenic maize in Mexico is discussed.     

Characterization of 24 porcine (dA-dC)n-(dT-dG)n microsatellites: genotyping of unrelated animals from four breeds and linkage studies

Twenty-four PCR primer pairs were designed for the detection of porcine microsatellites. Polymorphism was investigated in 76 unrelated animals from four different breeds: Duroc, Landrace, Hampshire, and Yorkshire. Compared with human microsatellites, a general lower heterozygosity was detected; however, for each microsatellite a significant variation between breeds in number of alleles and heterozygosity was seen. Mean heterozygosity was found to be significantly higher (P<0.01%) in the Yorkshire breed than in the other three breeds. Linkage analyses with the CEPH linkage packet were performed in a backcross family comprising 45 animals, of which 43 had informative meioses. Ten of the microsatellites could be assigned to six different linkage groups, demonstrating that linkage mapping with microsatellites can be carried out with great efficiency in a relatively small number of animals. Four of the linkage groups represent Chromosomes (Chrs) 4, 6, 7, and 8 respectively, while two linkage groups are unassigned.The nucleotide sequence data reported in this paper have been submitted to GenBank and have been assigned the accession numbers listed in Table 1.     

Reconstitution of the Turkey erythrocyte adenylate cyclase sensitivity to l-epinephrine upon re-insertion of the Lubrol solubilized components into phospholipid vesicles

Turkey erythrocyte adenylate cyclase was activated by GppNHp and l-epinephrine to its stable, highly active form. In this form the enzyme could be solubilized by Lubrol-PX and subsequently re-inserted into phospholipid vesicles concomitantly with the removal of up to 99.3% of the Lubrol. The ability of GTP and l-epinephrine to reverse the GppNHp/epinephrine activated state was taken as a measure for the reappearance of hormone sensitivity in the reconstituted vesicles. An incomplete but significant reappearance of hormone sensitivity in the reconstituted adenylate cyclase was achieved. This hormone sensitivity was found to be stereospecific for (?)epinephrine. The ¹²⁵I-cyanopindolol binding properties of the reconstituted β-receptor depend on the nature of the detergent and the phospholipids used in the reconstitution.     

Antipruritic and antihyperalgesic actions of loperamide and analogs

Loperamide and three of its analogs were evaluated for their ability to inhibit binding to cloned human opioid receptor subtypes and to produce antipruritis and antinociception following local s.c. administration to rodents. All four compounds were fully efficacious agonists with affinities of 2 to 4 nM for the cloned human mu opioid receptor. Local s.c. injection of loperamide, ADL 01-0001 or ADL 01-0002 at the same site as the introduction of the pruritogenic compound 48/80 resulted in antipruritic activity in a mouse model of itch. Similarly, i.paw or i.pl. administration of compounds ADL 01-0001, ADL 01-0002 and ADL 01-0003 to inflamed paws caused potent antinociception, inhibiting late phase formalin-induced flinching, Freund's adjuvant-induced mechanical hyperalgesia and tape stripping-induced mechanical hyperalgesia. Loperamide and its analogs were efficacious in animal models of itch and inflammatory pain, and may have potential therapeutic utility as antipruritic and antihyperalgesic agents.     

Modification of sialic acid metabolism of murine erythroleukemia cells by analogs of N-acetylmannosamine

Two analogs of N-acetylmannosamine, $\text{2-}\text{acetamido}\text{-1,3,4,6-}\text{tetra}\text{-O-}\text{acetyl}\text{-2-}\text{deoxy-}\text{d}\text{-mannopyranose}$ (Ac₄-NAcMan) and the 2-trifluoroacetamido derivative (Ac₄F₃-NAcMan), were synthesized as potential inhibitors of the formation of sialic acid-containing glycoconjugates and were examined for their ability to modify the incorporation of $\text{N-[}{}^3\text{H]acetylmannosamine}$ into cellular glycoconjugates of Friend murine erythroleukemia cells. Ac₄F₃-NAcMan and Ac₄-NAcMan inhibited cellular replication in suspension culture at concentrations of 0.02 and 0.08 mM, respectively. The cytotoxicity of Ac₄-NAcMan was relatively reversible, whereas that produced by Ac₄F₃-NAcMan was not, as judged by measurement of the cloning efficiencies of cells exposed to these agents. The analogs inhibited incorporation of $\text{N-[}{}^3\text{H]acetylmannosamine}$ into ethanol-soluble and -insoluble materials. Separation of ethanol-soluble metabolites by HPLC demonstrated that Ac₄F₃-NAcMan caused accumulation of radioactivity from $\text{N-[}{}^3\text{H]acetylmannosamine}$ in CMP-N-acetylneuraminic acid (CMP-NeuNAc) equal to the decrease in macromolecular-bound ³H caused by this agent. In contrast, similar exposure to Ac₄-NAcMan produced a large increase in the amount of radioactivity in ethanol-soluble N-acetylneuraminic acid while decreasing the amount of label from $\text{N-[}{}^3\text{H]acetylmannosamine}$ in cellular CMP-NeuNAc, suggesting that the analogs differ in their biochemical sites of action. Treatment of cells with either analog increased the amount of neuraminidase-hydrolyzable sialic acid-like material on the cell surface; this appeared to be due to the incorporation of the analogs into cellular glycoconjugates, since incubation of cells with ³H-labeled analogs resulted in the appearance of radioactivity in cellular ethanol-insoluble and neuraminidase-hydrolyzable material. Incubation of cells with Ac₄-NAcMan labeled with ¹⁴C in the 4-O-acetyl group further demonstrated that incorporation occurred with approx. 50% retention of this substituent. Thus, both the amount and the nature of the surface sialic acid constituents of treated cells were altered, suggesting that these or similar analogs could potentially be used to modify cellular membrane function.     

Serotonergic mechanisms of the lateral parabrachial nucleus and cholinergic-induced sodium appetite

Central cholinergic mechanisms are suggested to participate in osmoreceptor-induced water intake. Therefore, central injections of the cholinergic agonist carbachol usually produce water intake (i.e., thirst) and are ineffective in inducing the intake of hypertonic saline solutions (i.e., the operational definition of sodium appetite). Recent studies have indicated that bilateral injections of the serotonin receptor antagonist methysergide into the lateral parabrachial nucleus (LPBN) markedly increases salt intake in models involving the activation of the renin-angiotensin system or mineralocorticoid hormones. The present studies investigated whether sodium appetite could be induced by central cholinergic activation with carbachol (an experimental condition where only water is typically ingested) after the blockade of LPBN serotonergic mechanisms with methysergide treatment in rats. When administered intracerebroventricularly in combination with injections of vehicle into both LPBN, carbachol (4 nmol) caused water drinking but insignificant intake of hypertonic saline. In contrast, after bilateral LPBN injections of methysergide (4 microg), intracerebroventricular carbachol induced the intake of 0.3 M NaCl. Water intake stimulated by intracerebroventricular carbachol was not changed by LPBN methysergide injections. The results indicate that central cholinergic activation can induce marked intake of hypertonic NaCl if the inhibitory serotonergic mechanisms of the LPBN are attenuated.     

A comparative assessment of purification techniques for mesophyll protoplasts of Brassica napus L.

The effects of three different general purification protocols have been assessed quantitatively using mesophyll protoplasts of Brassica napus. Within the initial sample two distinct sub-populations were determined. The methods used influenced the ratio of the vacuolated to chloroplastic type protoplast sub-populations. Overall recovery rates of the initial sample varied according to the method used from 38% to 27%, but the relative recovery of the sub-populations varied considerably with a purified ratio of between 1.0:0.78 to 1.0:7.0. Size distribution profiles of the initial and purified populations are also presented.     

Growth Behavior and Fatty Acid Production of Probiotics,Pediococcus acidilactici and Lactococcus lactis,at Different Concentrations of Fructooligosaccharide: Studies Validating Clinical Efficacy of Selected Synbiotics on Growth Performance of Caspian Roach (Rutilus frisii kutum) Fry

Probiotics and Antimicrobial Proteins - Growth behavior and production of short-chain fatty acid (SCFA) of two probiotics, Pediococcus acidilactici and Lactococcus lactis, each at...