Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Drug conjugates and polymeric micelles for targeted delivery of kinase inhibitors

A variety of diseases is associated with dysregulation of kinase signaling pathways and kinase inhibitors are hence being considered as potent drugs for the treatment of cancer and inherited diseases such as polycystic kidney disease. Although kinase inhibitors are considered as quite specific drugs that are molecularly targeted, side effects significantly limit their therapeutic applications. Moreover, their specific action also infers that the efficacy of kinase inhibitors is limited by drug resistance. In this thesis, we have explored the development of drug delivery systems such as small molecule-drug conjugates (SMDCs) and polymeric micelles for kinase inhibitors, which eventually can be used to overcome these problems. An SMDC typically is composed of a targeting ligand, a drug payload and a spacer which infers a cleavable linkage with the drug (see Figure 3, Chapter 1). SMDCs have attracted tremendous interest in the pharmaceutical field because they have several advantageous features. Firstly, the small size (as can be deduced from their low molecular weight) of SMDCs enables them to accumulate and penetrate in solid tumors very efficiently. Secondly, the synthesis strategy of SMDCs is versatile and controllable. Polymeric micelles are colloidal nanoparticles with a diameter size around 10 - 200 nm and have a core-shell structure that is formed by self-assembling of amphiphilic block copolymers in aqueous media. The hydrophilic block of the copolymers forms the shell of polymeric micelles to ensure their colloidal stability while the hydrophobic block forms the core of polymeric micelles. Hydrophobic drugs can be loaded in the core by physical entrapment or -preferably, in view of stable drug retention- by chemical crosslinking to the core. The physicochemical properties of polymeric micelles can be controlled by adjusting the components of polymers and drugs. The relatively small size of polymeric micelles -although much larger than SMDCs- enables them to passively accumulate and subsequently penetrate into tumours via the enhanced permeability and retention (EPR) effect. The loaded drug can subsequently be released in the tumor microenvironment. In addition to passive targeting, the surface of polymeric micelles can be decorated with targeting ligands which can facilitate active receptor mediated uptake by cancer cells. This thesis is focused on the development of novel SMDCs and polymeric micelles exploiting platinum coordination chemistry for conjugation of the drug to the delivery system. As discussed below, we have explored and optimized the reaction conditions to form drug conjugates and drug loaded micelles primarily with the kinase inhibitor dactolisib, which is a potent inhibitor of signaling pathways involved in cancer and polycystic kidney disease. In conclusion, small molecule-drug conjugates and polymeric micelles exploiting platinum coordination chemistry described in this thesis can target deliver kinase inhibitors to the diseased cells and, potentially, exert cellular kinase inhibitory effect. The promising results from this thesis encourage the further application of these novel drug delivery systems for preclinical and clinical studies

Drug conjugates and polymeric micelles for targeted delivery of kinase inhibitors

A variety of diseases is associated with dysregulation of kinase signaling pathways and kinase inhibitors are hence being considered as potent drugs for the treatment of cancer and inherited diseases such as polycystic kidney disease. Although kinase inhibitors are considered as quite specific drugs that are molecularly targeted, side effects significantly limit their therapeutic applications. Moreover, their specific action also infers that the efficacy of kinase inhibitors is limited by drug resistance. In this thesis, we have explored the development of drug delivery systems such as small molecule-drug conjugates (SMDCs) and polymeric micelles for kinase inhibitors, which eventually can be used to overcome these problems. An SMDC typically is composed of a targeting ligand, a drug payload and a spacer which infers a cleavable linkage with the drug (see Figure 3, Chapter 1). SMDCs have attracted tremendous interest in the pharmaceutical field because they have several advantageous features. Firstly, the small size (as can be deduced from their low molecular weight) of SMDCs enables them to accumulate and penetrate in solid tumors very efficiently. Secondly, the synthesis strategy of SMDCs is versatile and controllable. Polymeric micelles are colloidal nanoparticles with a diameter size around 10 - 200 nm and have a core-shell structure that is formed by self-assembling of amphiphilic block copolymers in aqueous media. The hydrophilic block of the copolymers forms the shell of polymeric micelles to ensure their colloidal stability while the hydrophobic block forms the core of polymeric micelles. Hydrophobic drugs can be loaded in the core by physical entrapment or -preferably, in view of stable drug retention- by chemical crosslinking to the core. The physicochemical properties of polymeric micelles can be controlled by adjusting the components of polymers and drugs. The relatively small size of polymeric micelles -although much larger than SMDCs- enables them to passively accumulate and subsequently penetrate into tumours via the enhanced permeability and retention (EPR) effect. The loaded drug can subsequently be released in the tumor microenvironment. In addition to passive targeting, the surface of polymeric micelles can be decorated with targeting ligands which can facilitate active receptor mediated uptake by cancer cells. This thesis is focused on the development of novel SMDCs and polymeric micelles exploiting platinum coordination chemistry for conjugation of the drug to the delivery system. As discussed below, we have explored and optimized the reaction conditions to form drug conjugates and drug loaded micelles primarily with the kinase inhibitor dactolisib, which is a potent inhibitor of signaling pathways involved in cancer and polycystic kidney disease. In conclusion, small molecule-drug conjugates and polymeric micelles exploiting platinum coordination chemistry described in this thesis can target deliver kinase inhibitors to the diseased cells and, potentially, exert cellular kinase inhibitory effect. The promising results from this thesis encourage the further application of these novel drug delivery systems for preclinical and clinical studies

Nitrogen Addition Alleviates Cadmium Toxicity in <i>Eleocarpus glabripetalus</i> Seedlings

Cadmium (Cd) accumulation in soil is a serious form of heavy metal pollution affecting environmental safety and human health. In order to clarify the tolerance mechanisms to Cd-contaminated soils under N deposition, changes in plant growth, root architecture and physiological characteristics of Eleocarpus glabripetalus seedlings under combined nitrogen (N) and cadmium (Cd) treatments were determined in this study. The results indicated that Cd-induced negative effects inhibited the growth of E. glabripetalus seedlings through increased underground biomass allocation, and affected transpiration and respiratory processes, resulting in a decreased soluble sugars concentration in leaves and non-structural carbohydrates (NSC) in the roots. Root systems might play a major role in Cd absorption. Cd stress restricted the growth of fine roots (<0.5 mm), and affected the uptake of N and P. N addition alleviated the Cd-induced negative effect on plant growth through improving the root system, increasing starch and NSC contents in the roots and increasing total biomass. These findings have important implications for understanding the underlying tolerance mechanisms of Cd pollution under N deposition in arbor species

Effect of Fluoride on Endocytosis and Surface Marker Expression Levels of Mouse B Cells In Vitro

Background/Aims: To clarify the effect of fluoride on splenic B cells, the endocytosis and surface marker expression levels of mouse splenic B cells were detected in vitro by flow cytometry. Methods: Cells were stimulated with 10 µg/mL lipopolysaccharide (LPS) and varying concentrations of Sodium Fluoride (NaF) (0, 50 µM, 100 µM, 500 µM, 1000 µM). Results: The results demonstrated that the endocytic capacity of B cells was enhanced by NaF at 50µM. NaF significantly enhanced CD80 expression at 50 µM and decreased CD86 expression at 500 µM. CD40 and CD138 expression on B cells were down-regulated at varying high concentrations of NaF. Conclusion: our results showed that the endocytic capacity, expression levels of CD40 and CD80 of B cells changed significantly at lower concentrations, whereas expression levels of CD138 and CD86 changed significantly at higher concentrations, suggesting that fluoride could inhibit immune function in animals

Folate decorated polymeric micelles for targeted delivery of the kinase inhibitor dactolisib to cancer cells

One of the main challenges in clinical translation of polymeric micelles is retention of the drug in the nanocarrier system upon its systemic administration. Core crosslinking and coupling of the drug to the micellar backbone are common strategies to overcome these issues. In the present study, polymeric micelles were prepared for tumor cell targeting of the kinase inhibitor dactolisib which inhibits both the mammalian Target of Rapamycin (mTOR) kinase and phosphatidylinositol-3-kinase (PI3K). We employed platinum(II)-based linker chemistry to couple dactolisib to the core of poly(ethylene glycol)-b-poly(acrylic acid) (PEG-b-PAA) polymeric micelles. The formed dactolisib-PEG-PAA unimers are amphiphilic and self-assemble in an aqueous milieu into core–shell polymeric micelles. Folate was conjugated onto the surface of the micelles to yield folate-decorated polymeric micelles which can target folate receptor over-expressing tumor cells. Fluorescently labeled polymeric micelles were prepared using a lissamine-platinum complex linked in a similar manner as dactolisib. Dactolisib polymeric micelles showed good colloidal stability in water and released the coupled drug in buffers containing chloride or glutathione. Folate decorated micelles were avidly internalized by folate-receptor-positive KB cells and displayed targeted cellular cytotoxicity at 50–75 nM IC50. In conclusion, we have prepared a novel type of folate-receptor targeted polymeric micelles in which platinum(II) linker chemistry modulates drug retention and sustained release of the coupled inhibitor dactolisib

Short-Term Effect of the Addition of Rice Husk Gasification Slag on the Movement and Transformation of Phosphorus in Different Soil Types

Rice husk gasification slag (RS) is a type of biochar that is one of the main by-products generated from the production of biomass power with rice husk as the feed. This study aimed to explore the short-term effect of the application of RS on the movement and transformation of fertilizer P in two different soil types through an incubation experiment. The results showed that the RS addition had a significant influence on the diffusive movement of P in soil microsites close to fertilizer placements both in latosolic red soil and fluvo-aquic soil. After 50 d of incubation, most of the WE-P (water-extractable P), AE-P (acid-extractable P), and Olsen-P (available P) were concentrated within 0&ndash;5 mm from the fertilization site. WE-P, Olsen-P, and the movement amount of the P in the 0&ndash;5 mm soil section were significantly increased at all levels of the RS application in the fertilizer P both in the two soil types. The application of the RS reduced the sorption and precipitation of the fertilizer P in the soil and improved the efficiency of the fertilizer P. The findings presented in this study may be used as references in developing RS applications that reduce losses of fertilizer P and reduce environmental risks