Carvacrol and eugenol effectively inhibit Rhizopus stolonifer and control postharvest soft rot decay in peaches

Aims

This study aimed to investigate the antifungal mechanism of carvacrol and eugenol to inhibit Rhizopus stolonifer and the control of postharvest soft rot decay in peaches.

Methods and Results

To investigate the antifungal mechanism, the effects of carvacrol and eugenol on the mycelium growth, leakages of cytoplasmic contents, mycelium morphology, cell membrane and membrane composition of R. stolonifer were studied. Carvacrol and eugenol both exhibited dose‐dependent antifungal activity against R. stolonifer, carvacrol at a concentration of 2 μl per plant and eugenol at a concentration of 4 μl per plant inhibited fungal growth completely. The two essential oils (EOs) increased cell membrane penetrability and caused the leakage of cytoplasm, nucleic acid and protein content. The observation using scanning electron microscopy and fluorescent microscopy showed modification of the hyphal morphology and breakage of the cell plasma membrane. Decreased ergosterol contents confirmed that the two EOs could destroy the membrane of R. stolonifer. For the in vivo test, the inhibition of soft rot disease and the induction of defence‐related enzymes were investigated. Carvacrol and eugenol significantly reduced the incidence and severity of soft rot decay in inoculated peaches. The best treatments for controlling soft rot decay were obtained at 0·5 μl l^?1 for carvacrol and 1 μl l^?1 for eugenol. The activities of defence‐related enzymes in peaches were also enhanced by fumigation with two EOs.

Conclusion

This study showed that carvacrol and eugenol could effectively inhibit the growth of R. stolonifer in vitro and successfully control the incidence of soft rot decay in honey peaches.

Significance and Impact of the Study

The above findings may be the main antifungal mechanism of carvacrol and eugenol on R. stolonifer. Furthermore, carvacrol and eugenol are helpful for their commercial application on the preservation of fresh fruit.     

A novel fed-batch based cultivation method provides high cell-density and improves yield of soluble recombinant proteins in shaken cultures

Background  

Cultivations for recombinant protein production in shake flasks should provide high cell densities, high protein productivity per cell and good protein quality. The methods described in laboratory handbooks often fail to reach these goals due to oxygen depletion, lack of pH control and the necessity to use low induction cell densities. In this article we describe the impact of a novel enzymatically controlled fed-batch cultivation technology on recombinant protein production in Escherichia coli in simple shaken cultures.     

Attenuation of a virulent Aeromonas hydrophila with novobiocin and pathogenic characterization of the novobiocin‐resistant strain

Aim

To determine whether novobiocin resistance strategy could be used to attenuate a virulent Aeromonas hydrophila AH11P strain and to characterize the growth and pathogenic differences between the novobiocin‐resistant strain and its virulent parent strain AH11P.

Methods and Results

A novobiocin‐resistant strain AH11NOVO was obtained from a virulent Aer. hydrophila strain AH11P through selection of resistance to novobiocin. AH11NOVO was found to be avirulent to channel catfish (Ictalurus punctatus), whereas AH11P was virulent. When AH11NOVO vaccinated channel catfish were challenged with AH11P at 14 days postvaccination, relative per cent of survival of vaccinated fish was 100%. The cell proliferation rate of AH11NOVO was found to be significantly (P < 0·05) less than that of AH11P. In vitro motility assay revealed that AH11NOVO was nonmotile, whereas AH11P was motile. AH11NOVO had significantly (P < 0·05) lower in vitro chemotactic response to catfish mucus than that of AH11P. Although the ability of AH11NOVO to attach catfish gill cells was similar to that of AH11P, the ability of AH11NOVO to invade catfish gill cells was significantly (P < 0·05) lower than that of AH11P.

Conclusions

The novobiocin‐resistant AH11NOVO is attenuated and different from its parent AH11P in pathogenicity.

Significance and Impact of the Study

The significantly lower chemotactic response and invasion ability of AH11NOVO compared with that of its virulent parent strain AH11P might shed light on the pathogenesis of Aer. hydrophila.     

Genes of the most conserved WOX clade in plants affect root and flower development in Arabidopsis

Background  

The Wuschel related homeobox (WOX) family proteins are key regulators implicated in the determination of cell fate in plants by preventing cell differentiation. A recent WOX phylogeny, based on WOX homeodomains, showed that all of the Physcomitrella patens and Selaginella moellendorffii WOX proteins clustered into a single orthologous group. We hypothesized that members of this group might preferentially share a significant part of their function in phylogenetically distant organisms. Hence, we first validated the limits of the WOX13 orthologous group (WOX13 OG) using the occurrence of other clade specific signatures and conserved intron insertion sites. Secondly, a functional analysis using expression data and mutants was undertaken.     

Genetic variations and haplotypes in TIM-3 gene and the risk of gastric cancer

Purpose  

T cell immunoglobulin and mucin domain-containing molecule 3 (TIM-3) could weaken the Th1-mediated anti-tumor responses and accelerate the tumor cell proliferation by inhabiting the production of IL-2 or IFN-γ. This study was to assess the association between TIM-3 genetic variations and the development of gastric cancer.     

A Combined test using both cell sediment and supernatant cell‐free DNA in pleural effusion shows increased sensitivity in detecting activating EGFR mutation in lung cancer patients

Introduction

The aim of this study was to examine whether a combined test using both cell sediment and supernatant cytology cell‐free DNA (ccfDNA) is more useful in detecting EGFR mutation than using cell sediment DNA or supernatant ccfDNA alone in pleural effusion of lung cancer patients.

Methods

A total of 74 lung adenocarcinoma patients with paired samples between primary tumour and corresponding metastatic tumour with both cell sediment and supernatant ccfDNA of pleural effusion cytology were enrolled in this study. Cell sediment and supernatant ccfDNA were analysed separately for EGFR mutations by polymerase chain reaction.

Results

Out of 45 patients with mutant EGFR in primary tumours, EGFR mutations were detected in 23 cell sediments of corresponding metastases (sensitivity; 51.1%) and 20 supernatant ccfDNA corresponding metastases (sensitivity; 44.4%). By contrast, the combined test detected EGFR mutations in 27 corresponding metastases (sensitivity; 60.0%), and had a higher sensitivity than the cell sediment or the supernatant ccfDNA alone (P < .05). Out of 45 patients with mutant EGFR, 24, three and 18 were cytologically diagnosed as positive, atypical or negative, respectively. The detection rate in the combined test was highest (95.8%) in the positive group, and mutant EGFR was also detected in four of 18 samples (22.2%) in the negative group.

Conclusions

A combined test using both cell sediment DNA and supernatant ccfDNA samples increases the concordance rate of EGFR mutations between primary tumour and corresponding metastases. Our findings indicate that supernatant ccfDNA is useful even in cases where the cytological diagnosis is negative.     

Comparative performance of contact plates,electrostatic wipes,swabs and a novel sampling device for the detection of Staphylococcus aureus on environmental surfaces

Aims

To evaluate the performance of four sampling methods [contact plates, electrostatic wipes (wipe), swabs and a novel roller sampler] for recovery of Staphylococcus aureus from a stainless steel surface.

Methods and Results

Stainless steel test plates were inoculated with Staph. aureus, dried for 24 h and sampled using each of the four methods. Samples were either incubated directly (roller, contact plate) or processed using elution and membrane filtration (swab, wipe). Performance was assessed by calculating the apparent sampling efficiency (ASE), analytical sensitivity (Sn) and percentage of replications with positive growth. The wipe demonstrated the best performance across all inoculating concentrations (ASE_48 h = 18%; Sn_48 h = 7 CFU per 100 cm²). The swab performed well when corrected for area actually sampled (ASE_48 h = 24%; Sn_48 h = 76 CFU per 100 cm²). Of the contact‐based methods, the newly developed roller sampler outperformed the contact plate (roller: ASE_48 h = 10%; Sn_48 h = 17 CFU per 100 cm²; contact plate: ASE_48 h = 0·04%; Sn_48 h = 1412 CFU per 100 cm²); both contact samplers performed better at higher inoculating concentrations (6E3 CFU per 100 cm² for the roller and 6E6 CFU per 100 cm² for the contact plate). Overall, the electrostatic wipe produced the highest number of replications resulting in positive growth (74%_24 h, 91%_48 h).

Conclusions

This study demonstrates that selection of the sampling method must be carefully considered, given that different methods have varying performance.

Significance and Impact of the Study

This is the first study assessing static wipes for sampling and one that uses a more real‐world‐relevant 24‐h drying time. The results help with infection control, and environmental health professionals choose better sampling methodologies.     

Para‐psychobiotic Lactobacillus gasseri CP2305 ameliorates stress‐related symptoms and sleep quality

Aims

To confirm the stress‐relieving effects of heat‐inactivated, enteric‐colonizing Lactobacillus gasseri CP2305 (paraprobiotic CP2305) in medical students taking a cadaver dissection course.

Methods and Results

Healthy students (21 males and 11 females) took paraprobiotic CP2305 daily for 5 weeks during a cadaver dissection course. The General Health Questionnaire and the Pittsburgh Sleep Quality Index were employed to assess stress‐related somatic symptoms and sleep quality respectively. The aggravation of stress‐associated somatic symptoms was observed in female students (P = 0·029). Sleep quality was improved in the paraprobiotic CP2305 group (P = 0·038), particularly in men (P = 0·004). Among men, paraprobiotic CP2305 shortened sleep latency (P = 0·035) and increased sleep duration (P = 0·048). Diarrhoea‐like symptoms were also effectively controlled with CP2305 (P = 0·005) in men. Thus, we observed sex‐related differences in the effects of paraprobiotic CP2305. In addition, CP2305 affected the growth of faecal Bacteroides vulgatus and Dorea longicatena, which are involved in intestinal inflammation.

Conclusions

CP2305 is a potential paraprobiotic that regulates stress responses, and its beneficial effects may depend on specific cell component(s).

Significance and Impact of the Study

This study characterizes the effects of a stress‐relieving para‐psychobiotic in humans.     

OppA,the ecto-ATPase of <Emphasis Type="Italic">Mycoplasma hominis</Emphasis>induces ATP release and cell death in HeLa cells

Background  

In the facultative human pathogen Mycoplasma hominis, which belongs to the cell wall-less Mollicutes, the surface-localised substrate-binding domain OppA of the oligopeptide permease was characterised as the main ecto-ATPase.     

Associations between duration of first trimester intrauterine exposure to genocide against the Tutsi and health outcomes in adulthood

Objectives

Hundreds of thousands of Rwandans were conceived during the 1994 genocide against the Tutsi, including thousands conceived by genocidal rape. We explore whether the duration of first trimester exposure to the genocide is associated with variation in adult mental health outcomes in individuals exposed to varying degrees of genocide-related stress in utero.

Materials and Methods

We recruited 30 Rwandans conceived via genocidal rape, 31 Rwandans conceived by genocide survivors not raped, and 30 individuals of Rwandan-descent who were conceived outside of Rwanda at the time of the genocide (control group). Individuals were age- and sex-matched across groups. Adult mental health was assessed through standardized questionnaires for vitality, anxiety, and depression.

Results

Among the genocide only group, a longer duration of first trimester prenatal exposure was associated with higher anxiety scores and lower vitality (both p < 0.010), and higher depression scores (p = 0.051). Duration of first trimester exposure was not associated with any measures of mental health among the genocidal rape or control group.

Discussion

Duration of exposure to genocide in the first trimester of gestation was associated with variation in adult mental health among the genocide only group. The lack of association between duration of first trimester exposure to genocide and adult mental health in the genocidal rape group may reflect the fact that stress associated with conception through rape persisted beyond the genocide period itself, encompassing all of gestation and likely beyond. Geopolitical and community interventions are needed in the context of extreme events during pregnancy to mitigate adverse intergenerational outcomes.     

Composite effects of gene determinants on the translation speed and density of ribosomes

Background  

Translation is a central process of life, and its regulation is crucial for cell growth. In this article, focusing on two model organisms, Escherichia coli and Saccharomyces cerevisiae, we study how three major local features of a gene's coding sequence (its adaptation to the tRNA pool, its amino acid charge, and its mRNA folding energy) affect its translation elongation.     

Effects of extracellular DNA and DNA‐binding protein on the development of a Streptococcus intermedius biofilm

Aims

The aim of this study was to clarify the effects of homologous and heterologous extracellular DNAs (eDNAs) and histone‐like DNA‐binding protein (HLP) on Streptococcus intermedius biofilm development and rigidity.

Methods and Results

Formed biofilm mass was measured with 0·1% crystal violet staining method and observed with a scanning electron microscope. The localizations of eDNA and extracellular HLP (eHLP) in formed biofilm were detected by staining with 7‐hydoxyl‐9H‐(1,3‐dichloro‐9,9‐dimethylacridin‐2‐one) and anti‐HLP antibody without fixation, respectively. DNase I treatment (200 U ml^?1) markedly decreased biofilm formation and cell density in biofilms. Colocalization of eHLP and eDNA in biofilm was confirmed. The addition of eDNA (up to 1 μg ml^?1) purified from Strep. intermedius, other Gram‐positive bacteria, Gram‐negative bacteria, or human KB cells into the Strep. intermedius culture increased the biofilm mass of all tested strains of Strep. intermedius, wild‐type, HLP‐downregulated strain and control strains. In contrast, the addition of eDNA (>1 μg ml^?1) decreased the biofilm mass of all Strep. intermedius strains.

Conclusions

These findings demonstrated that eDNA and eHLP play crucial roles in biofilm development and its rigidity.

Significance and Impact of the Study

eDNA‐ and HLP‐targeting strategies may be applicable to novel treatments for bacterial biofilm‐related infectious diseases.     

Isolation of Cronobacter spp. (formerly Enterobacter sakazakii) from infant food, herbs and environmental samples and the subsequent identification and confirmation of the isolates using biochemical, chromogenic assays, PCR and 16S rRNA sequencing

Background  

Cronobacter spp. (formerly Enterobacter sakazakii), are a group of Gram-negative pathogens that have been implicated as causative agents of meningitis and necrotizing enterocolitis in infants. The pathogens are linked to infant formula; however, they have also been isolated from a wide range of foods and environmental samples.     

Deletion of the glycosyltransferase <Emphasis Type="Italic">bgsB of Enterococcus faecalis</Emphasis>leads to a complete loss of glycolipids from the cell membrane and to impaired biofilm formation

Background  

Deletion of the glycosyltransferase bgsA in Enterococcus faecalis leads to loss of diglucosyldiacylglycerol from the cell membrane and accumulation of its precursor monoglucosyldiacylglycerol, associated with impaired biofilm formation and reduced virulence in vivo. Here we analyzed the function of a putative glucosyltransferase EF2890 designated biofilm-associated glycolipid synthesis B (bgsB) immediately downstream of bgsA.     

Biochanin A improves fibre fermentation by cellulolytic bacteria

Aims

The objective was to determine the effect of the isoflavone biochanin A (BCA) on rumen cellulolytic bacteria and consequent fermentative activity.

Methods and Results

When bovine microbial rumen cell suspensions (n = 3) were incubated (24 h, 39°C) with ground hay, cellulolytic bacteria proliferated, short‐chain fatty acids were produced and pH declined. BCA (30 μg ml^?1) had no effect on the number of cellulolytic bacteria or pH, but increased acetate, propionate and total SCFA production. Addition of BCA improved total digestibility when cell suspensions (n = 3) were incubated (48 h, 39°C) with ground hay, Avicel, or filter paper. Fibrobacter succinogenes S85, Ruminococcus flavefaciens 8 and Ruminococcus albus 8 were directly inhibited by BCA. Synergistic antimicrobial activity was observed with BCA and heat killed cultures of cellulolytic bacteria, but the effects were species dependent.

Conclusions

These results indicate that BCA improves fibre degradation by influencing cellulolytic bacteria competition and guild composition.

Significance and Impact of the Study

BCA could serve as a feed additive to improve cellulosis when cattle are consuming high‐fibre diets. Future research is needed to evaluate the effect of BCA on fibre degradation and utilization in vivo.     

CRK9 contributes to regulation of mitosis and cytokinesis in the procyclic form of Trypanosoma brucei

Background  

The Trypanosoma brucei cell cycle is regulated by combinations of cyclin/CRKs (cdc2 related kinases). Recently, two additional cyclins (CYC10, CYC11) and six new CRK (CRK7-12) homologues were identified in the T. brucei genome database [1,2].     

Germ cell development in the Honeybee (Apis mellifera); Vasa and Nanos expression

Background  

Studies of specification of germ-cells in insect embryos has indicated that in many taxa the germ cells form early in development, and their formation is associated with pole plasm, germ plasm or an organelle called the oosome. None of these morphological features associated with germ cell formation have been identified in the Honeybee Apis mellifera. In this study I report the cloning and expression analysis of Honeybee homologues of vasa and nanos, germ cell markers in insects and other animals.