Synthesis of oxidative metabolites of CRA13 and their analogs: Identification of CRA13 active metabolites and analogs thereof with selective CB2R affinity

CRA13; a peripheral dual CB₁R/CB₂R agonist with clinically proven analgesic properties, infiltrates into CNS producing adverse effects due to central CB₁R agonism. Such adverse effects might be circumvented by less lipophilic compounds with attenuated CB₁R affinity. Metabolism produces less lipophilic metabolites that might be active metabolites. Some CRA13 oxidative metabolites and their analogues were synthesized as less lipophilic CRA13 analogues. Probing their CB₁R and CB₂R activity revealed the alcohol metabolite 8c as a more potent and more effective CB₂R ligand with attenuated CB₁R affinity relative to CRA13. Also, the alcohol analogue 8b and methyl ester 12a possessed enhanced CB₂R affinity and reduced CB₁R affinity. The CB₂R binding affinity of alcohol analogue 8b was similar to CRA13 while that of methyl ester 12a was more potent. In silico study provided insights into the possible molecular interactions that might explain the difference in the elicited biological activity of these compounds.     

Bioconversion of starch processing waste to Phellinus linteus mycelium in solid-state cultivation

The objective of the experiment was to use starch processing waste as an alternative growth medium for cultivation of mycelia of the mushroom Phellinus linteus and to find an optimum condition under solid-state cultivation. Response surface analysis along with a central composite design was successfully applied to approximate the simultaneous effects of the substrate concentration (16-36 g l(-1)), pH (4.5-6.5), and temperature (25-35 degrees C) on the mycelial growth rate. In the model, pH and temperature significantly affected the mycelial growth but substrate concentration did not. The optimal substrate concentration, pH, and temperature for maximizing growth rate of P. linteus mycelia were found to be 16.5 g l(-1), pH 6.0, and 29.7 degrees C, respectively. Subsequent verification of these levels agreed with model predictions and the maximum mycelial growth rate at these conditions was 6.1 +/- 0.8 mm day(-1). Therefore, the results of the experiments suggest that starch processing waste could be utilized as a growth substrate for the cultivation of the mushroom mycelia of P. linteus, enhancing the usefulness of this byproduct of the starch manufacturing industry. This approach is likely to be useful for establishing similar parameters for the cultivation of other fungi.     

A novel bioreactor with an internal adsorbent for integrated fermentation and recovery of prodigiosin-like pigment produced from Serratia sp. KH-95

A novel bioreactor with an internal adsorbent was developed for the simultaneous fermentation and recovery of prodigiosin-like pigment produced from Serratia sp. KH-95 as a model product in one bioreactor. The pigment concentration recovered in the internal adsorbent was 13.1 g l^–1, which was 1.8-fold higher than that obtained in a bioreactor with an external adsorbent.     

Responses of embryogenic mango cultures and seedling bioassays to a partially purified phytotoxin produced by a mango leaf isolate of Colletotrichum gloeosporioides penz

Summary Colletotrichum gloeosporioides Penz., the causal agent of mango anthracnose, produces a phytotoxin in vitro. The partially purified phytotoxin, presumably colletotrichin, caused anthracnose-like symptoms on young mango leaves, was toxic to embryogenic suspension cultures of two mango cultivars, ‘Hindi’ and ‘Carabao,’ and inhibited in vitro seed germination of two nonhosts, lettuce and tobacco. There were linear relationships between concentration of the partially purified phytotoxin and mortality of mango embryogenic cultures. Embryogenic cultures grown in the presence of the partially purified phytotoxin showed significantly lower growth rates than the controls. Similarly, embryogenic cultures grown in the presence of 40% (vol/vol) fungal culture filtrate showed significantly lower growth rates than unchallenged controls. Medium containing 40% (vol/vol) Czapek-Dox fungal broth did not reduce growth of embryogenic cultures, indicating the production of phytotoxin in vitro. The results suggest that either fungal culture filtrate or purified phytotoxin can be used as in vitro selection agents to screen for resistance to this fungus.     

Nup211, the fission yeast homolog of Mlp1/Tpr,is involved in mRNA export

Synthetic lethal mutants have been previously isolated in fission yeast Schizosaccharomyces pombe, which genetically interact with spmex67, in order to identify the genes involved in mRNA export. The nup211 gene was isolated by complementation of the growth defect in one of the synthetic lethal mutants, SLMex2, under synthetic lethal condition. We showed that Nup211, fission yeast homolog of Mlpl/Mlp2/Tpr, is essential for vegetative growth and Nup211-GFP proteins expressed at endogenous level are localized mainly in nuclear periphery. The accumulation of poly(A)⁺ RNA in the nucleus is exhibited when expression of nup211 is repressed or over-expressed. These results suggest that the Nup211 protein plays a pivotal role of mRNA export in fission yeast.     

Ultraviolet radiation: effects on risks of prostate cancer and other internal cancers

Governmental and research agencies worldwide have strongly advocated sun avoidance strategies in an attempt to counter marked increases in skin cancer incidence. Concurrently, there are reports describing widespread Vitamin D3 deficiency. Because 1,25-dihydroxyvitamin D3, through interaction with the Vitamin D receptor, exerts pleiotrophic effects, such deficiency might be expected to have clinical consequences. Indeed, various reports indicate that exposure to ultraviolet radiation (UVR) exerts a protective effect on development of some common diseases including internal cancers and multiple sclerosis. We describe studies indicating that modest exposure reduces risk of prostate cancer. The effect of UVR is mediated by skin type; at lower levels of exposure a relative inability to effect skin pigmentation is protective presumably because it allows more efficient Vitamin D3 synthesis. Polymorphic variants in genes associated with pigmentation including melanocyte stimulating hormone receptor and tyrosinase are also associated with prostate cancer risk. Overall, though preliminary and requiring cautious interpretation, these data indicate that moderate UVR exposure together with characteristics linked with less effective tanning confer reduced prostate cancer risk. Clearly, it is important to define safe levels of UVR that do not result in increased risk of skin cancers such as malignant melanoma.     

Cloning and functional expression of the gene encoding an inhibitor against <Emphasis Type="Italic">Aspergillus flavus</Emphasis> α-amylase,a novel seed lectin from <Emphasis Type="Italic">Lablab purpureus</Emphasis> (<Emphasis Type="Italic">Dolichos lablab</Emphasis>)

Maize is one of the more important agricultural crops in the world and, under certain conditions, prone to attack from pathogenic fungi. One of these, Aspergillus flavus, produces toxic and carcinogenic metabolites, called aflatoxins, as byproducts of its infection of maize kernels. The alpha-amylase of A. flavus is known to promote aflatoxin production in the endosperm of these infected kernels, and a 36-kDa protein from the Lablab purpureus, denoted AILP, has been shown to inhibit alpha-amylase production and the growth of A. flavus. Here, we report the isolation of six full-length labAI genes encoding AILP and a detailed analysis of the activities of the encoded proteins. Each of the six labAI genes encoded sequences of 274 amino acids, with the deduced amino acid sequences showing approximately 95-99% identity. The sequences are similar to those of lectin members of a legume lectin-arcelin-alpha-amylase inhibitor family reported to function in plant resistance to insect pests. The labAI genes did not show any of the structures characteristic of conserved structures identified in alpha-amylase inhibitors to date. The recombinant proteins of labAI-1 and labAI-2 agglutinated human red blood cells and inhibited A. flavus alpha-amylase in a manner similar to that shown by AILP. These data indicate that labAI genes are a new class of lectin members in legume seeds and that their proteins have both lectin and alpha-amylase inhibitor activity. These results are a valuable contribution to our knowledge of plant-pathogen interactions and will be applicable for developing protocols aimed at controlling A. flavus infection.     

Chaperone-aided expression of LipA and LplA followed by the increase in α-lipoic acid production

α-Lipoic acid (LA), a naturally occurring cofactor reported to be present in a diverse group of microorganisms, plants, and animal tissues, has been widely and successfully used as a therapy for a variety of diseases, including diabetes and heart disease. However, to date, recombinant DNA technology has not been applied for higher LA production due mainly to difficulties in the functional expression of key enzymes involved in LA production. Here, we report a study for higher LA production with the aid of chaperone plasmids, DnaKJE and trigger factor (Tf). The lipA and lplA genes encoding lipoate synthase and lipoate protein ligase in Pseudomonas fluorescens, respectively, were cloned and transformed into Escherichia coli K12. When they were overexpressed in E. coli, both LipA and LplA were expressed as inclusion bodies leading to no increase in LA production. However, when chaperone plasmids DnaKJE and Tf were coexpressed with lipA and lplA, the resulting recombinant E. coli strains showed higher LA production than the wild-type E. coli by 32–111%, respectively.