A novel antibacterial peptide derived from Crocodylus siamensis haemoglobin hydrolysate induces membrane permeabilization causing iron dysregulation, oxidative stress and bacterial death

Aims A novel antibacterial peptide from Crocodylus siamensis haemoglobin hydrolysate (CHH) was characterized for antimicrobial activity. Methods and Results CHHs were hydrolysed for 2 h (2 h-CHH), 4 h (4h-CHH), 6 h (6 h-CHH) and 8 h (8 h-CHH). The 8 h-CHH showed antibacterial activity against Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae and Pseudomonas aeruginosa at concentrations of 20, 20, 20 and 10 mg ml−1 (w/v) respectively. Fluorescent microscopy revealed that the 8 h-CHH had bactericidal activity against E. coli and P. aeruginosa. β-galactosidase assay supported by RT-qPCR demonstrated that the 8 h-CHH resulted in differential expression of genes involved in iron homeostasis (ftnA and bfd) and oxidative stress (sodA, soxR and oxyR). Siderophore assay indicated that the 8 h-CHH also impaired siderophore production with diminished expression of pvdF. This pattern of gene expression suggests that the 8 h-CHH triggers the release of free ferric ions in the cytoplasm. However, decreased expression of genes associated with the SOS response (recA and lexA) in combination with neutral comet revealed that no DNA damage was caused by 8 h-CHH. Membrane permeabilization assay indicated that 8 h-CHH caused membrane leakage thought to mediate the antibacterial and iron-stress responses observed, due to loss of regulated iron transport. The novel active peptide from 8 h-CHH was determined as QAIIHNEKVQAHGKKVL (QL17), with 41% hydrophobicity and +2 net charge. Conclusions The QAIIHNEKVQAHGKKVL fragment of C. siamensis haemoglobin is antibacterial via a mechanism that likely relies on iron dysregulation and oxidative stress which results in bacterial death. Significance and Impact of the Study We have described for the first time, a novel peptide derived from C. siamensis haemoglobin hydrolysate that has the potential to be developed as a novel antimicrobial peptide

Effects of pre-transport fasting on the physiological responses of young cattle to 8-hour road transport

peer-reviewedThe effects of fasting animals for 8 h prior to an 8-h road journey and their ability to cope with the stress of transport were investigated. The treatments were: 1) fasted and then transported (n=20); 2) non-fasted and transported (n=18); 3) non-fasted at grass (n=18); 4) fasted then fasted (n=18), and 5) non-fasted then fasted (n=18). There was no significant difference in rectal body temperature, pre- or post-transport, or live weight among treatments on days 0 (pre-transport), 1, 4 or 10 (post-transport). The ambient relative humidity and temperature of the outside environment ranged from 82.8 to 99.8% and 9.9 to 14.5 oC, respectively. Holstein × Friesian bulls (230 kg) undergoing an 8-h transportation at stocking densities of 0.82 m2/animal showed physiological and haematological responses that were within normal referenced ranges. Animals that were fasted for 8 h and transported lost 9.4% of live weight while non-fasted transported animals lost 7.2%. The control non-fasted animals remaining at grass gained 2% of live weight. Animals that were fasted continuously but not transported and the initially non-fasted control animals that were subsequently fasted for 9 h lost 6.1% and 6.2% of live weight, respectively. There was no significant change in concentrations of globulin, glucose, urea, haemoglobin or fibrinogen, or in haematocrit percentage before or after transport. Transport reduced lymphocyte percentage (P < 0.001) and increased neutrophil percentage (P < 0.001) in the fasted and non-fasted animals. Following transport, protein concentration was greater (P ≤0.001) in the fasted and transported animals than in the non-fasted animals at grass and haptoglobin concentrations were higher (P ≤0.001) in the fasted plus transported animals than the controls at grass. In conclusion, from the physiological and haematological measurements, an 8-h journey time, even without access to feed for 8 h prior to transport did not appear to impact negatively on animal welfare

Predominant utilization of V beta 8+ T cell receptor genes in the H-2Ld- restricted cytotoxic T cell response against the immediate-early protein pp89 of the murine cytomegalovirus

Cytotoxic T cell responses to the murine Cytomegalovirus (MCMV) were elicited in BALB/c mice (H-2d) by infectious virus. Eight days after infection, MCMV-primed local lymph node T cells were either depleted for T cells expressing a V beta 8+ TCR or separated into V beta 8+ and V beta 8- subpopulations by a cell sorter using the mAb F23.1. T cells were then expanded in vitro under limiting dilution conditions in the presence of IL-2 and in the absence of viral Ag to avoid selection by Ag in vitro. Frequencies of CTL precursors specific for the Immediate- Early-Ag 1 of MCMV and restricted to H-2Ld were determined. L cells of the endogenous haplotype H-2k cotransfected with the genes for MCMV-IE 1 and H-2Ld were used as target cells. Detection of a CTL response required previous priming of the animals by infection in vivo (less than 1/10(6) for nonimmunized animals). In primed animals CTL precursors of this specificity and restriction were three to fivefold more frequent in the V beta 8+ population (1/9.900 to 1/22.300) than in the V beta 8- population (1/57.000 to 1/87.200). Control experiments showed that frequencies were not influenced by the treatment with the anti-V beta 8-antibody and the fluorescein-labeled anti-Ig itself. V beta 8+ and V beta 8- T cells did not reveal any frequency differences when several other responses were determined (TNP-specific self- restricted CTL precursor; Th cells specific for keyhole limpet hemocyanin or Listeria monocytogenes)

Bounds on free energy in QCD

We derive some exact bounds on the free energy $W(J)$ in QCD, where $J_\mu^b$ is a source for the gluon field $A_\mu^b$ in the minimal Landau gauge, and $W(J)$ is the generating functional of connected gluon correlators. Among other results, we show that for a static source $J(x) = h$ the free energy vanishes, $W(h) = 0$, together with its first derivative, ${\partial W(h) \over \partial h} = 0,$ for all $h$, no matter how strong. Thus the system does not respond to a static color probe. We also present numerical evaluations of the free energy $W(J)$ and find that the bounds are well satisfied and in fact undersaturated.Comment: 8 pages, 3 figures, Conference: Xth Quark Confinement and the Hadron Spectrum, October 8-12, 2012, TUM Campus Garching, Munich, German