Action mechanism and structural requirements of the antimicrobial peptides, gaegurins

AbstractGaegurins (GGNs) are a family of cationic, α-helical, antimicrobial peptides that were isolated from a Korean frog, Glandirana emeljanovi (formerly classified as Rana rugosa) and represent one of the structurally well-characterized groups. Among six gaegurins, gaegurin 4 (renamed herein esculentin-2EM), gaegurin 5 (brevinin-1EMa), and gaegurin 6 (brevinin-1EMb) have been investigated comprehensively in terms of structure–activity relationships. In this paper, we first suggest renaming of gaegurins according to a recently raised rule of systematic nomenclature. Then, the current understanding of gaegurins is reviewed by summarizing their structure–activity relationships. In particular competing arguments on gaegurins are synthetically inspected. Finally their action mechanism and structural requirements will be discussed

Synergistic effect of acetyl xylan esterase on xylanase reaction originated from Ochrovirga pacifica

Acetyl xylan esterase plays an important role in complete enzymatic hydrolysis of lignocellulosic materials into fermentable sugars. It hydrolyzes ester linkages of acetic acid in xylan polysaccharide and supports to enhance the activity of xylanase. This study was conducted to recognize and overexpress the acetyl xylan esterase gene found from Ochrovirga pacifica strain S85 which was isolated from Chuuk state, Micronesia. The genome sequence was analyzed with genome sequencer-FLX and acetyl xylan esterase gene (Axe) was detected. The gene had an open reading frame of 864 bp encoding a polypeptide of 287 amino acids. Theoretical molecular mass and isoelectric point (pI) were 32 kDa and 5.9, respectively. The deduced amino acid sequence of the Axe showed 35.1% similarity with both endo-1,4-β-xylanase B from Robiginitalea biformata HTCC2501. The mature protein displayed the catalytic residues classically found in enzymes belonged to GH16 family. Axe was cloned into pET11a vector and recombinant protein was expressed in E. coli BL21 (DE3), purified by nickel affinity chromatography and its purity was visualized on SDS-PAGE. Commercial xylanase activity was tested after treatment of recombinant acetyl xylan esterase (rAXE) to birchwood xylan substrate. The xylanase activity of rAXE treated sample was about 2 times higher than xylanase only treated sample. Please click Additional Files below to see the full abstract

Recombinant protein production in Escherichia coli by combining of signal peptide originated from Bacillus subtilis

We isolated chitosanase secreting B. subtilis CH2 and identified the chitosanase nucleotide sequence. Analyzed the sequence showed that it consisted of 813 bp, including 87 bp signal sequence. The signal sequence leads the target protein to the cell-membrane of the B. subtilis CH2 and then secret the chitosanase out of the cell. The signal peptide showed 6 amino acids deletion compared to other B. subtilis chitosanase signal peptides. The chitosanase sequence including signal peptide was cloned into pET11a vector without fusion and expressed in E. coli BL21(DE3). The expressed chitosanase in E. coli showed two distinct bands which represent the pro-chitosanase in cytoplasm and mature chitosanase in periplasm. Time frame induction and results showed that muture chitosanase was increased. Subsequently, we linked this chitosanase signal sequence in front of B. subtilis CH2 xylanase and human superoxide distimutase 1 (hSOD1) sequences, and expressed it in E. coli BL21(DE3). The recombinant xylanase and hSOD1 moved to periplasmic space with high efficiency. This signal sequence is useful for bio-medical protein production in E. coli. Please click Additional Files below to see the full abstract

Hydrogen-bonded multilayer of pH-responsive polymeric micelles with tannic acid for surface drug delivery

We report the design of a platform for the delivery of hydrophobic drugs conjugated to block copolymer micelles via pH-responsive linkage that are assembled within hydrogen-bonded polymer multilayer thin films.close465

Transcriptional regulatory networks underlying the reprogramming of spermatogonial stem cells to multipotent stem cells

Spermatogonial stem cells (SSCs) are germline stem cells located along the basement membrane of seminiferous tubules in testes. Recently, SSCs were shown to be reprogrammed into multipotent SSCs (mSSCs). However, both the key factors and biological networks underlying this reprogramming remain elusive. Here, we present transcriptional regulatory networks (TRNs) that control cellular processes related to the SSC-to-mSSC reprogramming. Previously, we established intermediate SSCs (iSSCs) undergoing the transition to mSSCs and generated gene expression profiles of SSCs, iSSCs and mSSCs. By comparing these profiles, we identified 2643 genes that were up-regulated during the reprogramming process and 15 key transcription factors (TFs) that regulate these genes. Using the TF-target relationships, we developed TRNs describing how these TFs regulate three pluripotency-related processes (cell proliferation, stem cell maintenance and epigenetic regulation) during the reprogramming. The TRNs showed that 4 of the 15 TFs (Oct4/Pou5f1, Cux1, Zfp143 and E2f4) regulated cell proliferation during the early stages of reprogramming, whereas 11 TFs (Oct4/Pou5f1, Foxm1, Cux1, Zfp143, Trp53, E2f4, Esrrb, Nfyb, Nanog, Sox2 and Klf4) regulated the three pluripotency-related processes during the late stages of reprogramming. Our TRNs provide a model for the temporally coordinated transcriptional regulation of pluripotency-related processes during the SSC-to-mSSC reprogramming, which can be further tested in detailed functional studies.111Ysciescopuskc

Bucillamine prevents cisplatin-induced ototoxicity through induction of glutathione and antioxidant genes.

Bucillamine is used for the treatment of rheumatoid arthritis. This study investigated the protective effects of bucillamine against cisplatin-induced damage in auditory cells, the organ of Corti from postnatal rats (P2) and adult Balb/C mice. Cisplatin increases the catalytic activity of caspase-3 and caspase-8 proteases and the production of free radicals, which were significantly suppressed by pretreatment with bucillamine. Bucillamine induces the intranuclear translocation of Nrf2 and thereby increases the expression of γ-glutamylcysteine synthetase (γ-GCS) and glutathione synthetase (GSS), which further induces intracellular antioxidant glutathione (GSH), heme oxygenase 1 (HO-1) and superoxide dismutase 2 (SOD2). However, knockdown studies of HO-1 and SOD2 suggest that the protective effect of bucillamine against cisplatin is independent of the enzymatic activity of HO-1 and SOD. Furthermore, pretreatment with bucillamine protects sensory hair cells on organ of Corti explants from cisplatin-induced cytotoxicity concomitantly with inhibition of caspase-3 activation. The auditory-brainstem-evoked response of cisplatin-injected mice shows marked increases in hearing threshold shifts, which was markedly suppressed by pretreatment with bucillamine in vivo. Taken together, bucillamine protects sensory hair cells from cisplatin through a scavenging effect on itself, as well as the induction of intracellular GSH

Development and evaluation of a plant-based air filter system for bacterial growth control

We investigated a novel plant-based air filter system for bacterial growth control. The volatile components released from the experimental plant (Cupressus macrocarpa) were used as the basis of the bacterial growth control and inhibition. We monitored the effect of light on the gas exhausted from the system, and we found that the presence of light induced an increase in the O2 concentration and a decrease in the CO2 concentration in the exhaust gas. A variety of Gram-positive and -negative bacteria was used to elucidate the effect of the exhaust gas on bacterial growth. In the Bacillus subtilis cultivation aerated with the exhaust gas (batch mode), we observed a decrease in the specific growth rate (μ = 0.227 h-1) compared with the control experiments (0.257 h-1). The same result was observed for the Staphylococcus aureus cultivation aerated with the exhaust gas. In the case of Gram-negative bacterial cultivation aerated with the gas, no significant inhibitory effect of the exhaust gas on the bacterial growth was observed. When the number of bacteria (B. subtilis) in a continuous culture was varied at different aeration rates (between 50 to 200 mL/min) using the exhaust gas, a prominent inhibitory effect was observed. Preliminary gas analysis showed that the major inhibitory factors in the exhaust gas are α- and β-pinene and linalool. The results show that the air filter system used in this study could be applied not only as a methodological aspect for estimating antibacterial activity but also for bacteria control in a given system.Keywords: Plant-based biofilter, Cupressus macrocarpa, Bacillus subtilis, Staphylococcus aureus, α-pinene, β-pineneAfrican Journal of Biotechnology Vol. 12(16), pp. 2027-203