Near-infrared fluorescence (NIRF) molecular imaging has been widely applied to monitoring therapy of cancer and other diseases in preclinical studies; however, this technology has not been applied ...successfully to monitoring therapy for Alzheimer’s disease (AD). Although several NIRF probes for detecting amyloid beta (Aβ) species of AD have been reported, none of these probes has been used to monitor changes of Aβs during therapy. In this article, we demonstrated that CRANAD-3, a curcumin analog, is capable of detecting both soluble and insoluble Aβ species. In vivo imaging showed that the NIRF signal of CRANAD-3 from 4-mo-old transgenic AD (APP/PS1) mice was 2.29-fold higher than that from age-matched wild-type mice, indicating that CRANAD-3 is capable of detecting early molecular pathology. To verify the feasibility of CRANAD-3 for monitoring therapy, we first used the fast Aβ-lowering drug LY2811376, a well-characterized beta-amyloid cleaving enzyme-1 inhibitor, to treat APP/PS1 mice. Imaging data suggested that CRANAD-3 could monitor the decrease in Aβs after drug treatment. To validate the imaging capacity of CRANAD-3 further, we used it to monitor the therapeutic effect of CRANAD-17, a curcumin analog for inhibition of Aβ cross-linking. The imaging data indicated that the fluorescence signal in the CRANAD-17–treated group was significantly lower than that in the control group, and the result correlated with ELISA analysis of brain extraction and Aβ plaque counting. It was the first time, to our knowledge, that NIRF was used to monitor AD therapy, and we believe that our imaging technology has the potential to have a high impact on AD drug development.
•Characterization of wet spun acrylic fiber manufacturing industry wastewater.•Microbubble-ozonation of acrylic fiber industry wastewater.•Improved organic removal and biodegradability by microbubble ...ozonation.
This work investigated microbubble-ozonation for the treatment of a refractory wet-spun acrylic fiber wastewater in comparison to macrobubble-ozonation. CODcr, NH3-N, and UV254 of the wastewater were removed by 42%, 21%, and 42%, respectively in the microbubble-ozonation, being 25%, 9%, and 35% higher than the removal rates achieved by macrobubble-ozonation at the same ozone dose. The microbubbles (with average diameter of 45μm) had a high concentration of 3.9×105 counts/mL at a gas flow rate of 0.5L/min. The gas holdup, total ozone mass-transfer coefficient, and average ozone utilization efficiency in the microbubble-ozonation were 6.6, 2.2, and 1.5 times higher than those of the macrobubble-ozonation. Greater generation of hydroxyl radicals and a higher zeta potential of the bubbles were also observed in the microbubble ozonation process. The biodegradability of the wastewater was also significantly improved by microbubble-ozonation, which was ascribed to the enhanced degradation of alkanes, aromatic compounds, and the many other bio-refractory organic compounds in the wastewater. Microbubble-ozonation can thus be a more effective treatment process than traditional macrobubble-ozonation for refractory wastewater produced by the acrylic fiber manufacturing industry.
Amyloid peptides and proteins are associated with the pathologies of numerous diseases. In the progression of a disease, amyloids exist in soluble and insoluble forms, which are the dominant species ...at different stages of the disease and they have different degrees of toxicity. However, differentiating between the soluble and insoluble forms is very challenging with small molecule probes due to multiple obstacles that need to be overcome. Inspired by the recognition principle of antibodies for sAβ, we hypothesized that the accessibility/tightness of soluble and insoluble amyloids could be utilized to design imaging probes to recognize different amyloid forms and the stereo-hindrance tuning strategy could be used to design imaging probes for selectively detecting the soluble amyloid beta (sAβ) species in Alzheimer's disease (AD). Herein, we demonstrated that tuning the stereo-hindrance of the phenoxy-alkyl chains at the 4-position of a curcumin scaffold could lead to certain selectivity for sAβ over insoluble Aβs (insAβ). Among the designed compounds,
showed a 68-fold higher affinity for sAβ than for insAβ (7.5 ± 10 nM
505.9 ± 275.9 nM). Moreover, our imaging data indicated that
was indeed capable of detecting sAβ
using 4 month old APP/PS1 mice, in which sAβ is the predominant species in the brain. In addition, we also demonstrated that
could be used to monitor the increase in sAβ loading from the ages of 4 months old to 12 months old. We believe that
can be a useful probe for selectively detecting sAβ species in AD and that our probe designing strategy can be applied to other amyloids and will have tremendous impact on AD drug development and other amyloid research.
ClpA is a widely conserved protease in bacteria that plays a key role in virulence. To investigate its specific mechanism of action in the pathogenicity of Paracidovorax citrulli (formerly Acidovorax ...citrulli) , we constructed a ClpA deletion mutant, Δ ClpA . The Δ ClpA mutant of P. citrulli displayed reduced virulence on melon seedlings, and reduced motility, swarming ability, and antioxidant capacity. On the other hand, the ClpA deletion of P. citrulli mutant reduced the resistance to elevated temperature and enhanced biofilm formation ability. Using qRT-PCR, we observed that ClpA negatively regulates the expression of the virulence-related genes virB , pilR , pilA , and fliM , while positively regulating hrpG , hrcQ , and trbC . Bacterial double hybrid and Glutathione-S-transferase pulldown (GST-pulldown) results showed that ClpA interacts directly with RepA, and negatively regulates the expression of RepA . After deletion of the RepA gene, the pathogenicity of P. citrulli was lost, biofilm formation ability was enhanced, and the expression of hrpG , pilR , and trbC was positively regulated. These results indicate that ClpA plays a key role in the regulation of several virulence traits of P. citrulli , paving the way for future studies to better elucidate the virulence mechanisms of this bacterial plant pathogen.
Pseudomonas syringae is an important plant pathogen, which could adapt many different environmental conditions. Under the nutrient-limited and other stress conditions, P. syringae produces nucleotide ...signal molecules, i.e., guanosine tetra/pentaphosphate ((p)ppGpp), to globally regulate gene expression. Previous studies showed that (p) ppGpp played an important role in regulating virulence factors in P. syringae pv. tomato DC3000 (PstDC3000) and P. syringae pv. syringae B728a (PssB728a). Here we present a comparative transcriptomic analysis to uncover the overall effects of (p)ppGpp-mediated stringent response in P. syringae.
In this study, we investigated global gene expression profiles of PstDC3000 and PssB728a and their corresponding (p)ppGpp
mutants in hrp-inducing minimal medium (HMM) using RNA-seq. A total of 1886 and 1562 differentially expressed genes (DEGs) were uncovered between the (p)ppGpp
mutants and the wild-type in PstDC3000 and PssB728a, respectively. Comparative transcriptomics identified 1613 common DEGs, as well as 444 and 293 unique DEGs in PstDC3000 and PssB728a, respectively. Functional cluster analysis revealed that (p) ppGpp positively regulated a variety of virulence-associated genes, including type III secretion system (T3SS), type VI secretion system (T6SS), cell motility, cell division, and alginate biosynthesis, while negatively regulated multiple basic physiological processes, including DNA replication, RNA processes, nucleotide biosynthesis, fatty acid metabolism, ribosome protein biosynthesis, and amino acid metabolism in both PstDC3000 and PssB728a. Furthermore, (p) ppGpp had divergent effects on other processes in PstDC3000 and PssB728a, including phytotoxin, nitrogen regulation and general secretion pathway (GSP).
In this study, comparative transcriptomic analysis reveals common regulatory networks in both PstDC3000 and PssB728a mediated by (p) ppGpp in HMM. In both P. syringae systems, (p) ppGpp re-allocate cellular resources by suppressing multiple basic physiological activities and enhancing virulence gene expression, suggesting a balance between growth, survival and virulence. Our research is important in that due to similar global gene expression mediated by (p) ppGpp in both PstDC3000 and PssB728a, it is reasonable to propose that (p) ppGpp could be used as a target to develop novel control measures to fight against important plant bacterial diseases.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The post-transcriptional regulator RsmA globally controls gene expression in bacteria. Previous studies showed that RsmA2 and RsmA3 played critical roles in regulating type III secretion system ...(T3SS), motility, syringafactin, and alginate productions in
pv.
strain DC3000 (
DC3000). In this study, we investigated global gene expression profiles of the wild-type
DC3000, the
mutant, and the
double mutant in the
-inducing minimum medium (HMM) and King's B (KB) medium. By comparing the
and
mutants to
DC3000, a total of 1358 and 1074 differentially expressed genes (DEGs) in HMM, and 870 and 1463 DEGs in KB were uncovered, respectively. When comparing the
mutant with the
mutant, 277 and 741 DEGs in HMM and KB, respectively, were revealed. Transcriptomic analysis revealed that the
,
, and
non-coding small RNAs (ncsRNAs) were positively affected by RsmA2 and RsmA3, while RsmA3 positively regulates the expression of the
gene and negatively regulates both
and
gene expression. Comparative transcriptomic analysis showed that RsmA2 and RsmA3 synergistically influenced the expression of genes involved in T3SS and alginate biosynthesis in HMM and chemotaxis in KB. RsmA2 and RsmA3 inversely affected genes involved in syringafactin production in HMM and ribosomal protein biosynthesis in KB. In addition, RsmA2 played a major role in influencing genes involved in sarcosine and thiamine biosynthesis in HMM and in mannitol and phosphate metabolism in KB. On the other hand, genes involved in fatty acid metabolism, cellulose biosynthesis, signal transduction, and stress responses were mainly impacted by RsmA3 in both HMM and KB; whereas RsmA3 played a major role in controlling genes involved in c-di-GMP, phosphate metabolism, chemotaxis, and capsular polysaccharide in HMM. Furthermore, regulation of syringafactin production and oxidative stress by RsmA2 and RsmA3 was experimentally verified. Our results suggested the potential interplay among the RsmA proteins, which exhibit distinct and overlapping roles in modulating virulence and survival in
under different nutritional conditions.
In many bacteria, OxyR acts as a transcriptional regulator that facilitates infection
via
degrading hydrogen peroxide (H
2
O
2
) generated by the host defense response. Previous studies showed that ...OxyR also plays an important role in regulating biofilm formation, cell motility, pili relate-genes expression, and surface polysaccharide production. However, the role of OxyR has not been determined in
Acidovorax citrulli
strain xjl12. In the current study, the qRT-PCR and western blot assays revealed that the expression level of
oxyR
was significantly induced by H
2
O
2
. The
oxyR
deletion mutant of
A. citrulli
was significantly impaired bacterial tolerance to oxidative stress and reduced catalase (CAT) activity. In addition,
oxyR
mutant resulted in reduced swimming motility, twitching motility, biofilm formation, virulence, and bacterial growth in
planta
by significantly affecting flagellin and type IV pili-related gene (
fliC
and
pilA
) expression. The qRT-PCR assays and western blot revealed that OxyR positively regulated the expression of
fliC
and
pilA.
Furthermore, bacterial one-hybrid assay demonstrated that OxyR directly affected
pilA
and
fliC
promoter. Through bacterial two-hybrid assay, it was found that OxyR can directly interact with PilA and FliC. These results suggest that OxyR plays a major role in the regulating of a variety of virulence traits, and provide a foundation for future research on the global effects of OxyR in
A. citrulli
.
A diversity-oriented one-pot synthesis of a series of membrane-permeable BF2-rigidified benzc,dindole N-heteroarene BBN and BBC dyes has been achieved from the condensation of two commercial ...components (benzc,dindol-2-one and a set of N-heteroarene derivatives that can be selected from thousands of commercially available sources) and the subsequent in situ BF2 complexation reaction. These dyes enjoy a set of excellent photophysical properties including the large Stokes shift, high solution and solid-state fluorescence, and excellent photostabilities.
Bacterial fruit blotch, caused by seed-borne pathogen
, poses a serious threat to the production of cucurbits globally. Although the disease can cause substantial economic losses, limited information ...is available about the molecular mechanisms of virulence. This study identified that, a random transposon insertion mutant impaired in the ability to elicit a hypersensitive response on tobacco. The disrupted gene in this mutant was determined to be
, which is predicted to encode a YggS family pyridoxal phosphate-dependent enzyme. YggS is a highly conserved protein among multiple organisms, and is responsible for maintaining the homeostasis of pyridoxal 5'-phosphate and amino acids in cells.
deletion mutant of
strain XjL12 displayed attenuated virulence, delayed hypersensitive response, less tolerance to H
O
and pyridoxine, increased sensitivity to antibiotic β-chloro-D-alanine, and reduced swimming. In addition, RNA-Seq analysis demonstrated that
was involved in regulating the expression of certain pathogenicity-associated genes related to secretion, motility, quorum sensing and oxidative stress response. Importantly, YggS significantly affected type III secretion system and its effectors
. Collectively, our results suggest that YggS is indispensable for
virulence and expands the role of YggS in the biological processes.
This study aimed to evaluate the influences of stewing modes, including high fire short time (HFST, 100°C/1 h), medium-high fire mid-length time (MFMT, 98°C/2 h), medium fire long time (MFLT, 90°C/3 ...h), and low fire ultra-length time (LFUT, 83°C/4 h) processing, on physicochemical parameters and flavour compound profile of Chinese Dagu chicken soup. The chicken soup prepared under the stewing mode of MFMT had smaller particle size (d 3,2 of 2.56 μm and d 4,3 of 1.73 μm), higher zeta potential (8.66 mV), and viscosity than the soups stewed under the other conditions. The umami-taste compounds, such as inosine 5'-monophosphate, and umami free amino acid were the most abundant in the soup stewed by MFMT (53.47 and 59.91 mg/100 mL, respectively). GC-MS results showed that the volatile compounds were mainly hexanal, octanal, heptanal, ( E,E )-2,4-decadienal, nonanal, and 1-octen-3-ol. Additionally, the results of measurements made with the electronic nose and electronic tongue indicated that the overall flavour of the four chicken soups varied significantly. In general, considering the stability and umami taste of chicken soup, as well as the time-saving need, it is recommended to use the MFMT mode to prepare the chicken soup.
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