Secretion of Recombinant Pediocin PA-1 by Bifidobacterium longum, Using the Signal Sequence for Bifidobacterial α-Amylase

A recombinant DNA, encoding the chimeric protein of the signal sequence for bifidobacterial α-amylase mature pediocin PA-1, was introduced into Bifidobacterium longum MG1. Biologically active pediocin PA-1 was successfully secreted from the strain and showed bactericidal activity against Listeria monocytogenes and the same molecular mass as native pediocin PA-1.     

Digestion by the larva of the pruinose scarab, Sericesthis geminata

An in vitro study of digestion by the subterranean larva of S. geminata revealed the presence of enzymes able to digest starch, trehalose, salicin, cellobiose, melibiose, maltose, sucrose, casein, and several forms of cellulose. The midgut is the major source of all enzymes except invertase and CMC-cellulase, for which hindgut preparations are more active. The pH values of the gut contents are: foregut 6.9, midgut 9.0 and hindgut 7.5. The midgut fluid is pumped forward into the foregut, and the carbohydrases in it are generally more active at the pH of the foregut than at the pH of the midgut. It is possible, therefore, that the foregut, which is itself insignificant as a source of enzymes, is the site of considerable carbohydrate digestion. The proteinase is inhibited 28% by trypsin inhibitors.

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Zusammenfassung Eine in vitro-Untersuchung über die Verdauungsvorgänge in den unterirdisch lebenden Larven von S. geminata wies Enzyme nach, die Stärke, Trehalose, Salicin, Cellobiose, Melibiose, Maltose, Rohrzucker, Kasein und mehrere Celluloseformen abbauen können. Versuche mit Vorder-, Mittel- und Enddarmextrakten zeigten, daß der Abbau von Rohrzucker und CMC-Cellulose in Ansätzen mit Enddarmpräparaten prozentual am höchsten war. Maximale Verdauung aller anderen geprüften Substrate erfolgte dagegen mit Mitteldarmpräparaten.Die pH-Werte betrugen im Vorderdarm 6,9, im Mitteldarm 9,0 und im Enddarm 7,5. Im Mittel- und Enddarm lagen die jewciligen optimalen pH-Werte für Maltose bei 6,5–7,0 und 7,5, für Melibiose bei 6,0–7,0 und 7,0–7,5, für Cellobiose bei 6,0–7,0 und 4,5, für Rohrzucker bei 7,0 und 6,0, für CMC bei 5,2 und 5,6.Die Verdauung unlöslicher Celluloseformen war durchweg gering, die der CMC dagegen beträchtlich.Die Mitteldarmflüssigkeit wird nach vorn in den Vorderdarm gepumpt. Die darin enthaltenen Carbohydrasen sind beim pH-Wert des Vorderdarmes meistens wirksamer als in dem des Mitteldarmes. Es ist deshalb möglich, daß im Vorderdarm, welcher selbst wahrscheinlich keine Enzyme produziert, doch eine beträchtliche Kohlenhydratverdauung stattfindet.Die Wirksamkeit der Proteinase wird durch bekannte Tryptin-Hemmstoffe um 28% reduziert.

     

Plant Regeneration from Isolated Microspore of Indica Rice

Isolated microspores of rice (Oryza saliva L.) cultivars, IR36and IR43, belonging to the recalcitrant indica subspecies werecultured. Two types of microspores were observed after isolationfrom the fresh anthers and from pre-cultured anthers—onetype consisted of vacuolated, larger-sized grains, while theother was composed of microspores of smaller sizes with densecytoplasm. Within few days in culture, all the smaller sizedgrains were dead, and only the large grains were viable andproduced pollen embryos. After 30 days from culture, microcalliwere transferred to semisolid modified Murashige and Skoog mediumcontaining 1 mg/liter each of kinetin and naphthaleneaceticacid and kept under continuous light at 25?C. IR36 showed onlycell division while IR43 gave 32 green plants from these experiments. (Received January 18, 1990; Accepted July 4, 1990)     

Novel (E)-3-(3-Oxo-4-substituted-3,4-dihydro-2H-benzo[b][1,4]oxazin-6-yl)-N-hydroxypropenamides as Histone Deacetylase Inhibitors: Design,Synthesis and Bioevaluation

Herein, we report the design, synthesis and evaluation of novel (E)-3-(3-oxo-4-substituted-3,4-dihydro-2H-benzo[b][1,4]oxazin-6-yl)-N-hydroxypropenamides ( 4 a – i , 7 a – g ) targeting histone deacetylases. Three human cancer cell lines were used to test the cytotoxicity of the synthesized compounds (SW620, colon; PC-3, prostate; NCI−H23, lung cancer); inhibitory activity towards HDAC; anticancer activity; as well as their impact on the cell cycle and apoptosis. As a result, compounds 4 a – i bearing the alkyl substituents seemed to be less potent than the benzyl-containing compounds 7 a – g in all biological assays. Compounds 7 e – f were found to be the most active HDAC inhibitors with IC₅₀ of 1.498±0.020 μM and 1.794±0.159 μM, respectively. In terms of cytotoxicity and anticancer assay, 7 e and 7 f also showed good activity with IC₅₀ values in the micromolar range. In addition, the cell cycle and apoptosis of SW620 were affected by compound 7 f in almost a similar manner to that of reference compound SAHA. Docking assays were carried out for analysis the binding mode and selectivity of this compound toward 8 HDAC isoforms. Overall, our data confirmed that the inhibition of HDAC plays a pivotal role in their anticancer activity.     

Toxoplasma antibody titers by indirect latex agglutination test in patients of Kangnam St. Mary's Hospital and Cheju Medical Center

Total 2,829 persons consisted of 1,019 general patients and 1,030 asthma-suspected patients who visited Kangnam St. Mary's Hospital and 780 general patients who visited Cheju Medical Center were examined for the antibody titers of Toxoplasma by indirect latex agglutination (ILA) test. Nineteen out of 1,019(1.86%) cases in general patients group, 11 out of 1,030(1.07%) cases in asthma patients group, and 45 out of 780(5.77%) cases in Cheju patients group showed positive ILA titers. Concerned with the age and ILA positive cases, general and asthma patients expressed more cases at thirties to sixties while Cheju patients showed high incidence at children and adolescents in addition to the above mentioned ages. Frequencies of ILA positive titers were highest in 1:32 and 1:64, and some cases showed 1:2,048 or higher titers.     

Internal pH crisis, lysine decarboxylase and the acid tolerance response of Salmonella typhimurium

Salmonella typhimurium possesses an adaptive response to acid that increases survival during exposure to extremely low pH values. The acid tolerance response (ATR) includes both log-phase and stationary-phase systems. The log-phase ATR appears to require two components for maximum acid tolerance, namely an inducible pH homeostasis system, and a series of acid-shock proteins. We have discovered one of what appears to be a series of inducible exigency pH homeostasis systems that contribute to acid tolerance in extreme acid environments. The low pH-inducible lysine decarboxylase was shown to contribute significantly to pH homeostasis in environments as low as pH 3.0. Under the conditions tested, both lysine decarboxylase and σ^s-dependent acid-shock proteins were required for acid tolerance but only lysine decarboxylase contributed to pH homeostasis. The cadBA operon encoding lysine decarboxylase and a lysine/cadaverine antiporter were cloned from S. typhimurium and were found to be 79% homologous to the cadBA operon from Escherichia coli . The results suggest that S. typhimurium has a variety of means of fulfilling the pH homeostasis requirement of the ATR in the form of inducible amino acid decarboxylases.     

Kinetic properties of a L-cysteine desulfhydrase-deficient mutant in the enzymatic formation of L-cysteine from D,L-ATC

Summary A mutant strain lacking in activity of L-cysteine desulfhydrase, a L-cysteine-decomposing enzyme, was screened after UV-treatment ofPseudomonas sp. CU6. The properties of the two strains, original and mutant, were compared on the basis of parameter values estimated from kinetic simulations of the enzymatic formation of L-cysteine from D,L-ATC. Both strains suffered from product inhibition, though inhibition was less for the mutant strain.     

Re-Identification on Korean Penicillium Sequences in GenBank Collected by Software GenMine

Penicillium species have been actively studied in various fields, and many new and unrecorded species continue to be reported in Korea. Moreover, unidentified and misidentified Korean Penicillium species still exist in GenBank. Therefore, it is necessary to revise the Korean Penicillium inventory based on accurate identification. We collected Korean Penicillium nucleotide sequence records from GenBank using the newly developed software, GenMine, and re-identified Korean Penicillium based on the maximum likelihood trees. A total of 1681 Korean Penicillium GenBank nucleotide sequence records were collected from GenBank. In these records, 1208 strains with four major genes (Internal Transcribed Spacer rDNA region, β-tubulin, Calmodulin and RNA polymerase II) were selected for Penicillium re-identification. Among 1208 strains, 927 were identified, 82 were identified as other genera, the rest remained undetermined due to low phylogenetic resolution. Identified strains consisted of 206 Penicillium species, including 156 recorded species and 50 new species candidates. However, 37 species recorded in the national list of species in Korea were not found in GenBank. Further studies on the presence or absence of these species are required through literature investigation, additional sampling, and sequencing. Our study can be the basis for updating the Korean Penicillium inventory.     

Detection of antimicrobial substances from larvae of the black soldier fly,Hermetia illucens (Diptera: Stratiomyidae)

Maggots have become highly successful in the treatment of non‐healing wounds and multidrug‐resistant pathogen infections. The main objective of this study was to extract antibacterial substances from larvae of the black soldier fly, Hermetia illucens. To induce immune responses, we septically injured the larvae with a contaminated needle. Lyophilized H. illucens larvae were homogenized and extracted with acidic methanol. We examined the antifungal and antibacterial effects of the low molecular weight antimicrobial factors within the larval extract on the growth of a broad range of microorganisms, including Gram‐positive Staphylococcus aureus, methicillin resistant Staphylococcus aureus (MRSA), and Gram‐negative Pseudomonas aeruginosa. Furthermore, we isolated the anti‐MRSA substances from the larval extract using high performance liquid chromatography. These investigations revealed that the larval extract possessed a broad‐spectrum of antibacterial activity, demonstrating that secretions of H. illucens larvae prove useful in the fight against MRSA and can potentially be a source of novel antibiotic‐like compounds for infection control.