Novel fast degradable thermosensitive polymeric micelles based on PEG-block-poly(N-(2-hydroxyethyl)methacrylamide-oligolactates)

The aim of this study was to design a thermosensitive polymeric micelle system with a relatively fast degradation time of around 1 day. These micelles are of interest for the (targeted) delivery of biologically active molecules. Therefore, N-(2-hydroxyethyl)methacrylamide-oligolactates (HEMAm-Lac(n)()) were synthesized and used as building blocks for biodegradable (block co) polymers. p(HEMAm-Lac(2)) is a thermosensitive polymer with a cloud point (CP) of 22 degrees C which could be lowered by copolymerization with HEMAm-Lac(4). The block copolymer PEG-b-((80%HEMAm-Lac(2))-(20%HEMAm-Lac(4))) self-assembled into compact spherical micelles with an average size of 80 nm above the CP of the thermosensitive block (6 degrees C). Under physiological conditions (pH 7.4; 37 degrees C), the micelles started to swell after 4 h and were fully destabilized within 8 h due to hydrolysis of the lactate side chains. Rapidly degrading thermosensitive polymeric micelles based on PEG-b-((80%HEMAm-Lac(2))-(20%HEMAm-Lac(4))) have attractive features as a (targeted) drug carrier system for therapeutic applications.     

Neutron Activated Samarium-153 Microparticles for Transarterial Radioembolization of Liver Tumour with Post-Procedure Imaging Capabilities

Introduction

Samarium-153 (¹⁵³Sm) styrene divinylbenzene microparticles were developed as a surrogate for Yttrium-90 (⁹⁰Y) microspheres in liver radioembolization therapy. Unlike the pure beta emitter ⁹⁰Y, ¹⁵³Sm possess both therapeutic beta and diagnostic gamma radiations, making it possible for post-procedure imaging following therapy.

Methods

The microparticles were prepared using commercially available cation exchange resin, Amberlite IR-120 H⁺ (620–830 μm), which were reduced to 20–40 μm via ball mill grinding and sieve separation. The microparticles were labelled with ¹⁵²Sm via ion exchange process with ¹⁵²SmCl₃, prior to neutron activation to produce radioactive ¹⁵³Sm through ¹⁵²Sm(n,γ)¹⁵³Sm reaction. Therapeutic activity of 3 GBq was referred based on the recommended activity used in ⁹⁰Y-microspheres therapy. The samples were irradiated in 1.494 x 10¹² n.cm^-2.s^-1 neutron flux for 6 h to achieve the nominal activity of 3.1 GBq.g^-1. Physicochemical characterisation of the microparticles, gamma spectrometry, and in vitro radiolabelling studies were carried out to study the performance and stability of the microparticles.

Results

Fourier Transform Infrared (FTIR) spectroscopy of the Amberlite IR-120 resins showed unaffected functional groups, following size reduction of the beads. However, as shown by the electron microscope, the microparticles were irregular in shape. The radioactivity achieved after 6 h neutron activation was 3.104 ± 0.029 GBq. The specific activity per microparticle was 53.855 ± 0.503 Bq. Gamma spectrometry and elemental analysis showed no radioactive impurities in the samples. Radiolabelling efficiencies of ¹⁵³Sm-Amberlite in distilled water and blood plasma over 48 h were excellent and higher than 95%.

Conclusion

The laboratory work revealed that the ¹⁵³Sm-Amberlite microparticles demonstrated superior characteristics for potential use in hepatic radioembolization.     

Resveratrol-induced apoptosis is enhanced in low pH environments associated with cancer

Many critical factors such as hypoxia, nutrient deficiency, activation of glycolytic pathway/Warburg effect contribute to the observed low pH in tumors compared to normal tissue. Studies suggest that such tumor specific acidic environment can be exploited for the development of therapeutic strategies against cancer. Independent observations show reduction in pH of mammalian cells undergoing internucleosomal DNA fragmentation and apoptosis. As such, our group has extensively demonstrated that anticancer mechanisms of different plant polyphenols involve mobilization of endogenous copper and consequent internucleosomal DNA breakage. Copper is redox active metal, an essential component of chromatin and is sensitive to subtle pH changes in its microenvironment. Here we explored whether, acidic pH promotes growth inhibition, apoptosis, and DNA damaging capacity of chemopreventive agent resveratrol. Our results reveal that growth inhibition and internucleosomal DNA fragmentation induced apoptosis in Capan-2 and Panc-28 pancreatic cancer cell lines (and not in normal HPDE cells) by resveratrol is enhanced at lower pH. Using comet assay, we further demonstrate that DNA breakage by resveratrol is enhanced with acidification. Membrane permeable copper specific chelator neocuproine (and not iron chelator orthophenanthroline) abrogated growth inhibition and apoptosis by resveratrol. Western blot results show enhanced activation of DNA laddering marker H2.aX by resveratrol at acidic pH that was reversed by neocuproine and not by orthophenanthroline. Our findings provide irrevocable proof that low pH environment can be turned into tumor weakness and assist in eradication of cancer cells by resveratrol.     

Effects of MASP-1 of the complement system on activation of coagulation factors and plasma clot formation

Background

Numerous interactions between the coagulation and complement systems have been shown. Recently, links between coagulation and mannan-binding lectin-associated serine protease-1 (MASP-1) of the complement lectin pathway have been proposed. Our aim was to investigate MASP-1 activation of factor XIII (FXIII), fibrinogen, prothrombin, and thrombin-activatable fibrinolysis inhibitor (TAFI) in plasma-based systems, and to analyse effects of MASP-1 on plasma clot formation, structure and lysis.

Methodology/Principal Findings

We used a FXIII incorporation assay and specific assays to measure the activation products prothrombin fragment F1+2, fibrinopeptide A (FPA), and activated TAFI (TAFIa). Clot formation and lysis were assessed by turbidimetric assay. Clot structure was studied by scanning electron microscopy. MASP-1 activated FXIII and, contrary to thrombin, induced FXIII activity faster in the Val34 than the Leu34 variant. MASP-1-dependent generation of F1+2, FPA and TAFIa showed a dose-dependent response in normal citrated plasma (NCP), albeit MASP-1 was much less efficient than FXa or thrombin. MASP-1 activation of prothrombin and TAFI cleavage were confirmed in purified systems. No FPA generation was observed in prothrombin-depleted plasma. MASP-1 induced clot formation in NCP, affected clot structure, and prolonged clot lysis.

Conclusions/Significance

We show that MASP-1 interacts with plasma clot formation on different levels and influences fibrin structure. Although MASP-1-induced fibrin formation is thrombin-dependent, MASP-1 directly activates prothrombin, FXIII and TAFI. We suggest that MASP-1, in concerted action with other complement and coagulation proteins, may play a role in fibrin clot formation.     

First report of paralytic shellfish poisoning (PSP) caused by Alexandrium tamiyavanichii in Kuantan Port,Pahang, East Coast of Malaysia

Harmful algal bloom (HAB) is a proliferation of algae, which naturally produce biotoxins and cause harmful effects to humans, the environment and organisms associated with it. Paralytic shellfish poisoning (PSP) was reported for the first time in Kuantan Port, Pahang, Malaysia, in November 2013, followed by a second episode in August 2014. The toxicity level reported during the second event was as high as 3500 μg of STX equiv./100 g shellfish. Ten people were hospitalized with PSP symptoms after consuming contaminated shellfish. This study was conducted at Kuantan Port to identify the organisms responsible for these events. Water samples were collected monthly for a period of 12 months beginning in September 2014. HAB species were identified based on their morphology using light and fluorescence microscopes, and their classification was supported by molecular evidence based on internal transcribed spacer (ITS) sequences. Monthly cell abundance of Alexandrium tamiyavanichii was measured at four sampling stations. Toxin production by three strains isolated from the area was determined using HPLC. Our results revealed the presence of several HAB species, including the PSP‐producing species A . tamiyavanichii . The highest cell density of A . tamiyavanichii was 840 cells L^?1. The presence of GTX components was detected in these strains. However, other toxin components could not be determined. This study reported, for the first time, the presence of PSP‐producing A . tamiyavanichii on the Pahang coast of east Peninsular Malaysia and confirmed that the PSP events in Kuantan Port were attributable to this species. The presence of this species further indicates that several safety measures need to be considered to safeguard public health, particularly in Pahang coastal waters.     

Distribution of detritivores in tropical forest streams of peninsular Malaysia: role of temperature,canopy cover and altitude variability

The diversity and abundance of macroinvertebrate shredders were investigated in 52 forested streams (local scale) from nine catchments (regional scale) covering a large area of peninsular Malaysia. A total of 10,642 individuals of aquatic macroinvertebrates were collected, of which 18.22 % were shredders. Biodiversity of shredders was described by alpha (α_average ), beta (β) and gamma diversity (γ) measures. We found high diversity and abundance of shredders in all catchments, represented by 1,939 individuals (range 6–115 and average per site of 37.29?±?3.48 SE) from 31 taxa with 2–13 taxa per site (α_average?=?6.98?±?0.33 SE) and 10–15 taxa per catchment (γ?=?13.33?±?0.55 SE). At the local scale, water temperature, stream width, depth and altitude were correlated significantly with diversity (Adj-R ²?=?0.205). Meanwhile, dissolved oxygen, stream velocity, water temperature, stream width and altitude were correlated to shredder abundance (Adj-R ²?=?0.242). At regional scale, however, water temperature was correlated negatively with β and γ diversity (r ²?=?0.161 and 0.237, respectively) as well as abundance of shredders (r ²?=?0.235). Canopy cover was correlated positively with β diversity (r ²?=?0.378) and abundance (r ²?=?0.266), meanwhile altitude was correlated positively with β (quadratic: r ²?=?0.175), γ diversity (quadratic: r ²?=?0.848) as well as abundance (quadratic: r ²?=?0.299). The present study is considered as the first report describing the biodiversity and abundance of shredders in forested headwater streams across a large spatial scale in peninsular Malaysia. We concluded that water temperature has a negative effect while altitude showed a positive relationship with diversity and abundance of shredders. However, it was difficult to detect an influence of canopy cover on shredder diversity.     

NSort/DB:An Intranuclear Compartment Protein Database

Distinct substructures within the nucleus are associated with a wide variety of important nuclear processes.Structures such as chromatin and nuclear pores have specific roles,while others such as Cajal bodies are more functionally varied.Understanding the roles of these membraneless intra-nuclear compartments requires extensive data sets covering nuclear and compartment-associated proteins.NSort/DB is a database providing access to intra-or sub-nuclear compartment associations for the mouse nuclear proteome.Based on resources ranging from large-scale curated data sets to detailed experiments,this data set provides a high-quality set of annotations of non-exclusive association of nuclear proteins with structures such as promyelocytic leukaemia bodies and chromatin.The database is searchable by protein identifier or compartment,and has a documented web service API.The search interface,web service and data download are all freely available online at http://www.nsort.org/db/.Availability of this data set will enable systematic analyses of the protein complements of nuclear compartments,improving our understanding of the diverse functional repertoire of these structures.     

Anti-bacterial activity of chitosan loaded plant essential oil against multi drug resistant K. pneumoniae

The development of antibiotic resistant in K. pneumoniae is an emerging thread worldwide due to the poor antimicrobial drugs. To overcome this issue, researchers are focused on plant material and their essential oils to fight against multi drug resistant bacteria. In this context, the current study was concentrated in medicinal plant of guva leaves and their essential oils to combat multi drug resistant bacterial infections. The essential oils were successfully screened and confirmed by HRLC-MS analysis. The anti-bacterial ability of the compounds were loaded into the chitosan nanoparticles and proved by FT-IR analysis. In addition, the chitosan loaded essential oils morphology was compared with chitosan alone in SEM analysis and suggested that the material was loaded successfully. Further, the anti-bacterial ability of the chitosan loaded essential oils were primarily confirmed by agar well diffusion method. At the 100 µg/mL of lowest concentration of chitosan loaded essential oils, the multi-drug resistant K. pneumoniae was inhibited with 96% and confirmed by minimum inhibition concentration experiment. Hence, all the experiments were proved that the essential oils were successfully loaded into the chitosan nanoparticles, and it has more anti-bacterial activity against multi-drug resistant K. pneumoniae.     

Proteome analysis and characterization of phenotypes of lesion mimic mutant spotted leaf 6 in rice

Rice spotted leaf 6 (spl6) mutant produces lesions caused by spontaneous cell death in the absence of pathogenic infection. Expression of this genetic trait was developmentally programmed. After the tillering stage, small red and brown lesions were initiated in groups on the leaf blade. Eventually, the lesions formed parallel lines along the midrib of the leaf. Under light and transmission electron microscopy, we observed that thylakoid membranes of mesophyll chloroplasts were progressively damaged in the nonspotted section of the mutant leaf. However, chloroplasts were absent in the mesophyll cells of the spotted area of the spl6 mutant. These results indicated that lesion formation of the spl6 mutant might be caused by oxidative burst. Proteome analysis revealed that 159 protein spots were up or downregulated in comparison between spotted leaves of the spl6 mutant plants and normal leaves of the wild type. Among them, protein disulfide isomerase (PDI), transketolase, thioredoxin peroxidase (TPX), ATP synthase, RuBisCO large subunit, and RuBisCO activase small subunit were not identified in the spl6 mutant but were abundant in the wild type. Especially, the absence of TPX and PDI might be the cause of the failure to protect cells against oxidative burst resulting in degradation of the thylakoid membranes and leading to programmed cell death and lesion development.