Histone acetylation dynamics regulating plant development and stress responses

Cellular and Molecular Life Sciences - Crop productivity is directly dependent on the growth and development of plants and their adaptation during different environmental stresses. Histone...     

Mutations in KERA, encoding keratocan, cause cornea plana

Specialized collagens and small leucine-rich proteoglycans (SLRPs) interact to produce the transparent corneal structure. In cornea plana, the forward convex curvature is flattened, leading to a decrease in refraction. A more severe, recessively inherited form (CNA2; MIM 217300) and a milder, dominantly inherited form (CNA1; MIM 121400) exist. CNA2 is a rare disorder with a worldwide distribution, but a high prevalence in the Finnish population. The gene mutated in CNA2 was assigned by linkage analysis to 12q (refs 4, 5), where there is a cluster of several SLRP genes. We cloned two additional SLRP genes highly expressed in cornea: KERA (encoding keratocan) in 12q and OGN (encoding osteoglycin) in 9q. Here we report mutations in KERA in 47 CNA2 patients: 46 Finnish patients are homozygous for a founder missense mutation, leading to the substitution of a highly conserved amino acid; and one American patient is homozygous for a mutation leading to a premature stop codon that truncates the KERA protein. Our data establish that mutations in KERA cause CNA2. CNA1 patients had no mutations in these proteoglycan genes.     

SOS response promotes horizontal dissemination of antibiotic resistance genes

Mobile genetic elements have a crucial role in spreading antibiotic resistance genes among bacterial populations. Environmental and genetic factors that regulate conjugative transfer of antibiotic resistance genes in bacterial populations are largely unknown. Integrating conjugative elements (ICEs) are a diverse group of mobile elements that are transferred by means of cell-cell contact and integrate into the chromosome of the new host. SXT is a approximately 100-kilobase ICE derived from Vibrio cholerae that encodes genes that confer resistance to chloramphenicol, sulphamethoxazole, trimethoprim and streptomycin. SXT-related elements were not detected in V. cholerae before 1993 but are now present in almost all clinical V. cholerae isolates from Asia. ICEs related to SXT are also present in several other bacterial species and encode a variety of antibiotic and heavy metal resistance genes. Here we show that SetR, an SXT encoded repressor, represses the expression of activators of SXT transfer. The 'SOS response' to DNA damage alleviates this repression, increasing the expression of genes necessary for SXT transfer and hence the frequency of transfer. SOS is induced by a variety of environmental factors and antibiotics, for example ciprofloxacin, and we show that ciprofloxacin induces SXT transfer as well. Thus, we present a mechanism by which therapeutic agents can promote the spread of antibiotic resistance genes.     

Hydrometallurgical application for treating a Nigerian chalcopyrite ore in chloride medium: Part I. Dissolution kinetics assessment

The dissolution kinetics of a Nigerian chalcopyrite ore in hydrochloric acid was studied in this article. Acid concentration, reaction temperature, and ore particle size were chosen as experimental parameters. The chemical and morphological studies of the ore before and after leaching at optimal conditions were carried out by X-ray diffraction (XRD) and scanning electron microscopy (SEM). It is revealed that increasing the acid concentration and system temperature and decreasing the ore particle size greatly enhances the dissolution rate. The dissolution kinetics was found to follow the shrinking core model for the diffusion control mechanism where the activation energy (E_a) of 32.92 kJ·mol?1 was obtained for the process and supported by morphological changes at a higher dissolution of 91.33%.     

Direct expression in Escherichia coli of a DNA sequence coding for human growth hormone.

DNA coding for human growth hormone was constructed by using chemically synthesised DNA in conjunction with enzymatically prepared cDNA. This 'hybrid' gene was expressed in Escherichia coli under the control of the lac promoter. A polypeptide was produced having the size and immunological properties characteristic of mature human growth hormone.     

Sonochemical synthesis of nanostructured nickel hydroxide as an electrodematerial for improved electrochemical energy storage application

A facile and fast approach for the synthesis of a nanostructured nickel hydroxide(Ni(OH)_2) via sonochemical technique is reported in the present study. The X-ray diffraction results confirmed that the synthesized Ni(OH)_2 was oriented in β-phase of hexagonal brucite structure. The nanostructured Ni(OH)_2 electrode exhibited the maximum specific capacitance of 1256 F/g at a current density of 200 mA/g in 1 M KOH_((aq)). Ni(OH)_2 electrodes exhibited the pseudocapacitive behavior due to the presence of redox reaction. It also exhibited long-term cyclic stability of 85% after 2000 cycles, suggesting that the nanostructured Ni(OH)_2 electrode will play a promising role for high performance supercapacitor application.     

Phospholipase Cgamma1 controls surface expression of TRPC3 through an intermolecular PH domain

Many ion channels are regulated by lipids, but prominent motifs for lipid binding have not been identified in most ion channels. Recently, we reported that phospholipase Cgamma1 (PLC-gamma1) binds to and regulates TRPC3 channels, components of agonist-induced Ca2+ entry into cells. This interaction requires a domain in PLC-gamma1 that includes a partial pleckstrin homology (PH) domain-a consensus lipid-binding and protein-binding sequence. We have developed a gestalt algorithm to detect hitherto 'invisible' PH and PH-like domains, and now report that the partial PH domain of PLC-gamma1 interacts with a complementary partial PH-like domain in TRPC3 to elicit lipid binding and cell-surface expression of TRPC3. Our findings imply a far greater abundance of PH domains than previously appreciated, and suggest that intermolecular PH-like domains represent a widespread signalling mode.