Lactoferrin-derived peptides and Lactoferricin chimera inhibit virulence factor production and biofilm formation in Pseudomonas aeruginosa

AIMS

To investigate the bactericidal activity of lactoferrin-derived peptides and a new LF-derived peptides chimera (LFchimera) against P. aeruginosa and the influence on virulence factors of P. aeruginosa.

METHODS AND RESULTS

Lactoferricin (LFcin) and lactoferrampin (LFampin) are highly bioactive peptides isolated from the N-terminal region of lactoferrin (LF) by pepsin digestion. In this study, we designed LFchimera containing LFcin amino acids 17-30 and LFampin amino acids 268-284. Pseudomonas aeruginosa cells were incubated in medium with peptides at different concentrations, and then the assays of viability, pyocyanin, elastase activity and biofilm formation of P. aeruginosa were performed. We found that the concentration-dependent antibactericidal activity and down-regulating pyocyanin, elastase and biofilm formation of LFchimera were significantly stronger than those of LF, LFcin, LFampin or LFcin plus LFampin.

CONCLUSIONS

Our results indicated that LF, LFcin, LFampin and LFchimera were potential candidates to combat P. aeruginosa, and LFchimera was the most effective in them.

SIGNIFICANCE AND IMPACT OF THE STUDY

The new LFchimera has better activity against P. aeruginosa than LF, LFcin and LFampin and may be a promising new compound for treatment of P. aeruginosa infection.

Properties of hepatitis C virus minigenome containing mutated 5'UTR region and luciferase transgene

Sequences at the 3'UTR of Hepatitis C virus (HCV) negative-strand (-)RNA play an important role in the initiation of positive-strand (+)RNA synthesis. However, the underlying mechanism in cellular context is still unclear. In this report, we designed several cDNA-based HCV-like minigenomes containing different mutations at the 5'UTR of (+)RNA. These (+)RNAs transcribed from the minigenomes in vitro were transfected into HCV replicon cells for producing (-)RNAs with deletions of different stem loops (SL) at the 3'-end. The results showed that expression of the antisense transgene from minigenome increased, when the minigenome containing deletion of SL-C1+D1+E1 at the 3'-end of (-)RNA was transfected into the HCV replicon cells compared to that of the full minigenome. The expression of the transgene from minigenome decreased using other mutant minigenomes containing deletions SL-A1, SL-A1+B1, and SL-A1+B1+C1 at the 3'-end of (-)RNA. Finally, the transgene from SL-C1+D1+E1 of (-)RNA using CMV promoter-driven minigenome was expressed at higher level than full minigenome in HCV replicon cell lines. These results indicated that the region of (-)RNA interacting with HCV replicase may locate in the SL-C1+D1+E1 region of (-)RNA.

KEYWORDS

Hepatitis C virus; minigenome; RNA dependent RNA polymerase; replication.

Dual-specificity phosphatase 26 is a novel p53 phosphatase and inhibits p53 tumor suppressor functions in human neuroblastoma

Chemoresistance is a major cause of treatment failure and poor outcome in neuroblastoma. In this study, we investigated the expression and function of dual-specificity phosphatase 26 (DUSP26), also known as mitogen-activated protein kinase phophatase-8, in human neuroblastoma. We found that DUSP26 was expressed in a majority of neuroblastoma cell lines and tissue specimens. Importantly, we found that DUSP26 promotes the resistance of human neuroblastoma to doxorubicin-induced apoptosis by acting as a p53 phosphatase to downregulate p53 tumor suppressor function in neuroblastoma cells. Inhibiting DUSP26 expression in the IMR-32 neuroblastoma cell line enhanced doxorubicin-induced p53 phosphorylation at Ser20 and Ser37, p21, Puma, Bax expression as well as apoptosis. In contrast, DUSP26 overexpression in the SK-N-SH cell line inhibited doxorubicin-induced p53 phosphorylation at Ser20 and Ser37, p21, Puma, Bax expression and apoptosis. Using in vitro and in vivo assays, we found that DUSP26 binds to p53 and dephosphorylates p53 at Ser20 and Ser37. In this report, we show that DUSP26 functions as a p53 phosphatase, which suppresses downstream p53 activity in response to genotoxic stress. This suggests that inhibition of this phosphatase may increase neuroblastoma chemosensitivity and DUSP26 is a novel therapeutic target for this aggressive pediatric malignancy.

Leukocyte telomere length is associated with cognitive performance in healthy women

BACKGROUND

Age-related cognitive decline begins in mid-life and continues with advancing age. Leukocyte telomere length (LTL) shortens with age, and inflammation and oxidative stress enhance this process. Shorter LTL is associated with dementia.

METHODS

The relationship between cognitive function and LTL was investigated in a cross-sectional study of 382 women (mean age 50.6 years, range 19-78), not diagnosed with any form of dementia or cognitive impairment, from the TwinsUK cohort using six tests from the Cambridge neuropsychological test automated battery (CANTAB).

RESULTS

After adjusting for age and estimated prior intellectual ability, we observed significant correlations of LTL with episodic memory and associated learning (PAL, p=0.032), recognition memory for non-verbal patterns (DMS, p=0.007), and working memory capacity (SSP, p=0.003). In pairs of twins discordant for LTL the twin with longer telomeres also had significantly better DMS (p<0.05) and SSP (p<0.013) scores than their co-twin with shorter telomeres. The correlations between these two scores and LTL was significant both in women over the median mean age and in those below the median age, and remained significant after statistical adjustment for potential confounders.

CONCLUSIONS

Leukocyte telomere length correlates with a subset of measures of cognitive performance, suggesting that it might be a biomarker of cognitive aging in women before the onset of dementia.

Con-specific neighbours may enhance compensation capacity in an invasive plant

Facilitation, both by inter- and intra-specific neighbours, is known to be an important process in structuring plant communities. However, only a small number of experiments have been reported on facilitation in plant invasions, especially between invasive con-specific individuals. Here, we focus on how con-specific neighbours of the invasive alien plant alligator weed affect the tolerance of alligator weed to herbivory by the introduced biological control agent, Agasicles hygrophila. We conducted greenhouse and garden experiments in which invasive plant density and herbivory intensity (artificial clipping and real herbivory) were manipulated. In the greenhouse experiment, artificial clipping significantly reduced plant biomass when plants were grown individually, but when con-specific neighbours were present in the same pot, biomass was not significantly different from control plants. Similarly, when compared to control plants, plants that were subjected to herbivory by A. hygrophila produced more biomass when grown with two con-specific neighbours than when grown alone. Real herbivory also resulted in an increased number of vegetative buds, and again when two con-specific neighbours were present this effect was increased (a 55.3% increase in buds when there was no neighbour, but a 111.6% increase in buds when two con-specific neighbours were present). In the garden experiment, in which plants were grown at high density (6 plants per pot), alligator weed fully recovered from defoliation caused by insects at levels from 20-30% to 100%. Our results indicate that the con-specific association may increase the compensatory ability to cope with intense damage in this invasive plant.

Femtosecond laser-drilling-induced HgCdTe photodiodes

Femtosecond-laser drilling may induce holes in HgCdTe with morphology similar to that induced by ion-milling in loophole technique. So-formed hole structures are proven to be pn junction diodes by the laser beam induced current characterization as well as the conductivity measurement. Transmission and photoluminescence spectral measurements on a n-type dominated hole-array structure give rise to different results from those of an ion-milled sample.

Evaluating the Importance of Stem Canker of Soybean in Iowa

The relative importance of stem canker of soybean in Iowa compared with other soybean diseases present in the state was assessed using data collected from over 3,400 soybean fields sampled in the Iowa Soybean Disease Survey that was conducted from 2005 to 2007. Symptomatic plant tissues from soybean plants with stem canker symptoms were cultured on acidified potato dextrose agar. The prevalence of stem canker on soybean in 2005 in Iowa was 2.6%; the disease was not detected in 2006 and 2007. In 2005, 63 isolates with Diaporthe/Phomopsis characteristics were collected. To identify isolates to fungal species and variety, single-spored isolates were subjected to polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and sequencing of the internal transcribed spacer (ITS) region. Fourteen isolates were identified as D. phaseolorum var. caulivora (northern stem canker) and 49 as Phomopsis longicolla. To quantify and compare the aggressiveness of D. phaseolorum var. caulivora isolates collected in Iowa, nine isolates were arbitrarily selected for components analysis. Incubation period, rate of lesion expansion, final lesion length, and time to plant death for each isolate were quantified. Significant differences in components of aggressiveness were detected among the nine isolates. Results from this work suggest stem canker is a minor disease of soybean in Iowa.

Galanin, galanin receptors, and drug targets

Galanin, a neuropeptide widely expressed in the central and peripheral nervous systems and in the endocrine system, has been shown to regulate numerous physiological and pathological processes through interactions with three G-protein-coupled receptors, GalR1 through GalR3. Over the past decade, some of the receptor subtype-specific effects have been elucidated through pharmacological studies using subtype selective ligands, as well as through molecular approaches involving knockout animals. In this chapter, we summarize the current data which constitute the basis of targeting GalR1, GalR2, and GalR3 for the treatment of various human diseases and pathological conditions, including seizure, Alzheimer's disease, mood disorders, anxiety, alcohol intake in addiction, metabolic diseases, pain and solid tumors.

Epidermal growth factor signalling and bone metastasis

Epidermal growth factor (EGF) signalling is well known for its multifaceted functions in development and tissue homoeostasis. The EGF family of ligands and receptors (ERBB family) have also been extensively investigated for their roles in promoting tumourigenesis and metastasis in a variety of cancer types. Recent findings indicate that EGF signalling is an important mediator of bone metastasis in breast, prostate and kidney cancers. The EGF signalling stimulates the growth of bone metastasis directly by increasing tumour cell proliferation and indirectly by engaging bone stromal cell in metastasis-promoting activities. Therefore, molecular targeting of ERBB receptors may benefit patients with bone metastasis and should be evaluated in clinical trials.