Part 3: Design and synthesis of proline-derived α2δ ligands

A potent series of substituted (2S,4S)-benzylproline α₂δ ligands have been designed from the readily available starting material (2S,4R)-hydroxy-l-proline. The ligands have improved pharmacokinetic profile over the (4S)-phenoxyproline derivatives described previously and have potential for development as oral agents for the treatment of neuropathic pain. Compound 16 has been progressed to clinical development.     

Uptake and distribution of potassium in tomato plants

Summary The uptake and distribution of potassium was examined in tomato plants, cv. Amberley Cross and Moneymaker, grown in peat/loam and given a nutrient feed either adequate or deficient in potassium.Detailed studies were also made of the distribution of potassium in various parts of tomato plants, cv. Amberley Cross, grown in sand and supplied with nutrient feeds containing four and seven concentrations of potassium. In these plants the concentration of potassium in stem, petiole and laminar tissue increased from the base to the apex of plants, irrespective of the potassium concentration in the nutrient feed. There was also a gradient of decreasing potassium concentration along leaves, from proximal to distal laminae. The concentration of potassium in all plant parts increased with increasing nutrient supply of potassium, petioles showing a greater response to nutrient potassium than laminar tissue.Marginal chlorosis and/or necrosis were observed when the potassium concentration in fully expanded leaves fell below 1.2 per cent of the dry weight for cv. Amberley Cross or 1.5 per cent for cv. Moneymaker. A 50 per cent incidence of chlorosis and/or necrosis occurred in leaf laminae containing 0.74 per cent potassium.Leaves rarely showed deficiency symptoms when the concentration of potassium in the petioles was higher than that in adjacent laminar tissue. However, chlorosis and/or necrosis occurred when the potassium concentration in petioles fell below that in laminae. In the diagnosis of the potassium status of tomato plants, the most suitable tissue for sampling for potassium analysis is considered to be the petioles of young fully expanded leaves.     

The antidepressant-like effect of Ocimum basilicum in an animal model of depression

We investigated the efficacy of Ocimum basilicum (OB) essential oils for treating depression related behavioral, biochemical and histopathological changes caused by exposure to chronic unpredictable mild stress (CUMS) in mice and to explore the mechanism underlying the pathology. Male albino mice were divided into four groups: controls; CUMS; CUMS plus fluoxetine, the antidepressant administered for pharmacological validation of OB; and CUMS plus OB. Behavioral tests included the forced swim test (FST), elevated plus-maze (EPM) and the open ?eld test (OFT); these tests were performed at the end of the experiment. We assessed serum corticosterone level, protein, gene and immunoexpression of brain-derived neurotropic factor (BDNF) and glucocorticoid receptors (GRs) as well as immunoexpression of glial fibrillary acidic protein (GFAP), Ki67, caspase-3 in the hippocampus. CUMS caused depression in the mice as evidenced by prolonged immobility in the FST, prolonged time spent in the open arms during the EPM test and reduction of open field activity in the OFT. OB ameliorated the CUMS induced depressive status. OB significantly reduced the corticosterone level and up-regulated protein and gene expressions of BDNF and GR. OB reduced CUMS induced hippocampal neuron atrophy and apoptosis, and increased the number of the astrocytes and new nerve cells. OB significantly increased GFAP-positive cells as well as BDNF and GR immunoexpression in the hippocampus.     

Distribution of acid invertase in the tomato plant

Acid invertase activity in Lycopersicon esculentum was highest in the locular wall of ripe fruit and lowest in roots. Activity was greater in leaf laminae than in petiole tissue and increased with leaf age, whereas there was more invertase in the upper part of the stem compared with the older portion. Activity in whole fruit increased with increasing ripeness and was greatest in overripe fruit. Of various tissues from a number of wild tomato species examined, the fruit of L. pimpinellifolium were particularly rich in the enzyme, in contrast to the fruit of L. hirsutum, L. hirsutum, var. glabratum and L. peruvianum which had low activity.     

Relationship between Meloidogyne arenaria and Aflatoxin Contamination in Peanut

Damaged and developing kernels of peanut (Arachis hypogaea) are susceptible to colonization by fungi in the Aspergillus flavus group which, under certain conditions, produces aflatoxins prior to harvest. Our objective was to determine whether infection of peanut roots and pods by Meloidogyne arenaria increases aflatoxin contamination of the kernels when peanut is subjected to drought stress. The experiment was a completely randomized 2-x-2 factorial with 6 replicates/treatment. The treatment factors were nematodes (plus and minus M. arenaria) and fungus (plus and minus A. flavus inoculum). The experiment was conducted in 2001 and 2002 in microplots under an automatic rain-out shelter. In treatments where A. flavus inoculum was added, aflatoxin concentrations were high (> 1,000 ppb) and not affected by nematode infection; in treatments without added fungal inoculum, aflatoxin concentrations were greater (P ≤ 0.05) in kernels from nematode-infected plants (1,190 ppb) than in kernels from uninfected plants (79 ppb). There was also an increase in aflatoxin contamination of kernels with increasing pod galling (r² = 0.83 in 2001, r² = 0.43 in 2002; P ≤ 0.04). Colonization of kernels by A. flavus increased with increasing pod galling (r² = 0.18; P = 0.04) in 2001 but not in 2002. Root-knot nematodes may have a greater role in enhancing aflatoxin contamination of peanut when conditions are not optimal for growth and aflatoxin production by fungi in the A. flavus group.     

Field uniformity of the Japonica rice region of Taiwan as estimated by relative genetic contribution

Summary Despite the concerns for genetic vulnerability that were raised in the 1970s, the field uniformity of the Japonica rice (Oryza sativa L.) region in Taiwan has increased since 1980 with over 82% of the cultivated areas being covered by as few as three varieties and over half of this hectarage by a single variety. Japanese plant introductions are the major ancestral contributors of genetic constituents for varieties released in Taiwan. The main constitution of the genetic base present in the field has changed little since 1971. Six common ancestors comprised 60%, 55%, 78%, and 77% of the genetic constituents present in the field in 1971, 1976, 1981, and 1986, respectively. These estimates revealed that at least 55% of the genes utilized in the last 15 years came from the same sources. Recent efforts in introducing new germ plasm sources to variety development should continue to alleviate the possible crop loss due to continuous monoculture.Research supported by National Science Council (NSC 78-0211-B005-14)