Termite mound emissions of CH4 and CO2 are primarily determined by seasonal changes in termite biomass and behaviour

Termites are a highly uncertain component in the global source budgets of CH₄ and CO₂. Large seasonal variations in termite mound fluxes of CH₄ and CO₂ have been reported in tropical savannas but the reason for this is largely unknown. This paper investigated the processes that govern these seasonal variations in CH₄ and CO₂ fluxes from the mounds of Microcerotermes nervosus Hill (Termitidae), a common termite species in Australian tropical savannas. Fluxes of CH₄ and CO₂ of termite mounds were 3.5-fold greater in the wet season as compared to the dry season and were a direct function of termite biomass. Termite biomass in mound samples was tenfold greater in the wet season compared to the dry season. When expressed per unit termite biomass, termite fluxes were only 1.2 (CH₄) and 1.4 (CO₂)-fold greater in the wet season as compared to the dry season and could not explain the large seasonal variations in mound fluxes of CH₄ and CO₂. Seasonal variation in both gas diffusivity through mound walls and CH₄ oxidation by mound material was negligible. These results highlight for the first time that seasonal termite population dynamics are the main driver for the observed seasonal differences in mound fluxes of CH₄ and CO₂. These findings highlight the need to combine measurements of gas fluxes from termite mounds with detailed studies of termite population dynamics to reduce the uncertainty in quantifying seasonal variations in termite mound fluxes of CH₄ and CO₂.     

Determination of Arsenic in Scalp Hair of Children and its Correlation with Drinking Water in Exposed Areas of Sindh Pakistan

This study was focused on the analysis of arsenic (As) levels in scalp hair of children (age, <10 years) collected from two towns of Khairpur, Pakistan, to evaluate the effects of As-contaminated groundwater. For comparative purposes, scalp hair samples of children were also collected from that area having low levels of As (<10 μg/L) in drinking water. Groundwater and scalp hair samples of children were collected and analyzed by electrothermal atomic absorption spectrometry prior to microwave-assisted acid digestion. The average As concentrations in groundwater samples of two towns, Thari Mirwah and Gambat, were found to be 28.5 and 98.3 μg/L, respectively. The range of As concentrations in scalp hair samples of children who belong to Thari Mirwah and Gambat was 1.25-1.61 μg/g and 1.73-3.63 μg/g, respectively. Twenty percent of the total children who belong to Gambat have skin lesions on their hands and feet. A positive correlation coefficient (R = 0.91-0.99) was obtained between As contents in drinking water and scalp hairs of children of both towns.     

Acid-Induced Formation of Molten Globule States in the Wild Type <Emphasis Type="Italic">Escherichia coli</Emphasis> 5-Enolpyruvylshikimate 3-Phosphate Synthase and its Three Mutated Forms: G96A,A183T and G96A/A183T

Recent advances in protein chemistry have led to progress in the understanding of protein folding and properties of possible intermediates during the folding of proteins. The molten globule (MG) state, a major intermediate of protein folding, has a denatured state with native-like secondary structure. In the present work, the acid-induced unfolding of wild type Escherichia coli 5-enolpyruvylshikimate 3-phosphate synthase (EPSPS) and its three different variants (G96A, A183T and G96A/A183T) were studied by far- and near-UV circular dichroism (CD), intrinsic fluorescent emission spectroscopy and 1-anilino naphthalene-8-sulfonate (ANS) binding. At pH < 3.0, these EPSPS variants acquire partially folded state, which show the characteristics of the MG state, e.g., a drastic reduction of defined tertiary structure and almost no change in the secondary structure. ANS binding experiments show that hydrophobic surface of these variants is exposed to a greater extent in comparison to the native form, at acidic pH. Wild type, G96A, A183T and G96A/A183T acquire MG states at pH 2.0, 1.5, 3.0 and 3.0, respectively, which show that pH stability of MG state of G96A has increased in comparison to wild type; and pH stability of MG states of two other mutants is lower than that of the wild type. The results suggest that there is a direct relationship between stability of protein and pH stability of its folding intermediates.     

Protective effects of Ephedra pachyclada extract on mouse models of carbon tetrachloride- induced chronic and acute liver failure

Inflammation and oxidation are two important factors in the pathogenesis of liver. Ephedra pachyclada (EP) is a traditional medical herb that has anti-inflammatory and anti-oxidant activities. During this study, anti-oxidant activities of the EP extract was measured in vitro by 2,2′- diphenyl-1-picrylhydrazyl (DPPH) and β-Carotene bleaching assays. Then, we examined possible in vivo hepatoprotective effects of EP extract on mouse models of carbon tetrachloride (CCl₄)-induced chronic and acute liver failure. To produce mouse models of chronic and acute liver injuries, male SW1 mice were interaperitoneally injected with 1 ml/kg body weight (bw) CCl₄ biweekly for 42 days and a single dose of 2 ml/kg bw, respectively. In the experimental groups, mouse models were treated with low (140 mg/kg bw) and high (1400 mg/kg bw) doses of the EP extract. Olive oil and water treated mice were considered as controls during model derivation and EP extract treatment respectively. The results showed the antioxidant activity of EP extract and a significant reduction of all parameters of CCl₄-induced liver injury such as relative liver weight, necrosis, fibrosis, inflammation, and serum aspartate transaminase (AST) and alanine aminotransferase (ALT) in mouse models of acute and chronic liver injury treated with EP extract. Therefore, EP induces its hepatoprotective effects probably by suppressing oxidative stress and inhibit inflammation in the liver and is able to protect the liver against CCl₄-induced acute and chronic injuries.     

Differential Roles of Intra-accumbal Orexin Receptors in Acquisition and Expression of Methamphetamine-Induced Conditioned Place Preference in the Rats

Neurochemical Research - A large amount of document has revealed that the orexin system in the reward circuity, including the nucleus accumbens (NAc), contributes to the modification of drug...     

Partial Chromosome Sequence of Spiroplasma citri Reveals Extensive Viral Invasion and Important Gene Decay

The assembly of 20,000 sequencing reads obtained from shotgun and chromosome-specific libraries of the Spiroplasma citri genome yielded 77 chromosomal contigs totaling 1,674 kbp (92%) of the 1,820-kbp chromosome. The largest chromosomal contigs were positioned on the physical and genetic maps constructed from pulsed-field gel electrophoresis and Southern blot hybridizations. Thirty-eight contigs were annotated, resulting in 1,908 predicted coding sequences (CDS) representing an overall coding density of only 74%. Cellular processes, cell metabolism, and structural-element CDS account for 29% of the coding capacity, CDS of external origin such as viruses and mobile elements account for 24% of the coding capacity, and CDS of unknown function account for 47% of the coding capacity. Among these, 21% of the CDS group into 63 paralog families. The organization of these paralogs into conserved blocks suggests that they represent potential mobile units. Phage-related sequences were particularly abundant and include plectrovirus SpV1 and SVGII3 and lambda-like SpV2 sequences. Sixty-nine copies of transposases belonging to four insertion sequence (IS) families (IS30, IS481, IS3, and ISNCY) were detected. Similarity analyses showed that 21% of chromosomal CDS were truncated compared to their bacterial orthologs. Transmembrane domains, including signal peptides, were predicted for 599 CDS, of which 58 were putative lipoproteins. S. citri has a Sec-dependent protein export pathway. Eighty-four CDS were assigned to transport, such as phosphoenolpyruvate phosphotransferase systems (PTS), the ATP binding cassette (ABC), and other transporters. Besides glycolytic and ATP synthesis pathways, it is noteworthy that S. citri possesses a nearly complete pathway for the biosynthesis of a terpenoid.Spiroplasmas are arthropod-associated bacteria belonging to the class Mollicutes, a group of wall-less microorganisms phylogenetically related to low-G+C-content, Gram-positive bacteria (51). Spiroplasma citri is a helical plant-pathogenic mollicute responsible for the “stubborn” disease of citrus (39). It inhabits the phloem sap of infected plants to which it is transmitted by sap-sucking hemipteran insect in a circulative and propagative manner (31, 32). S. citri can infect a wide range of plant species, including crop and wild plants, as it is transmitted by polyphagous leafhoppers (13). Spiroplasmas are available in pure culture, and their study has therefore benefited from the use of molecular genetics. In particular, the relationships of spiroplasmas with their two hosts, the plant and the leafhopper vector, have been extensively studied (11, 22). In S. citri, the inactivation of genes and functional complementation of mutants have shown that (i) fructose consumption by the spiroplasma is a major cause for symptom production in plants, (ii) the solute binding protein of a putative ABC-type transporter is involved in the insect transmission process, and (iii) spiralin, the major membrane protein, is not essential for helicity, motility, and pathogenicity but is required for efficient transmission by the leafhopper vector (10, 19, 23, 24, 28). To characterize other spiroplasma genes potentially involved in insect transmission and pathogenicity, the genome of S. citri strain GII3-3X is currently being deciphered.The S. citri genome is characterized by an abundance of extrachromosomal elements, including seven plasmids, pSciA and pSci1 to pSci6, present as 10 to 14 copies per cell. These plasmids are vertically inherited, but some of them could also be horizontally transferred, as they encode proteins involved in partitioning and the cell-to-cell transfer of DNA molecules (12, 40). Plasmids pSci1 to pSci5 encode surface proteins of the S. citri adhesion-related protein (ScARP) family, and pSci6 was previously shown to confer insect transmissibility (9). Therefore, it is likely that the abundance and diversity of plasmids could provide S. citri strain GII3-3X with the ability to quickly adapt to various vector insects and, hence, to be transmitted to diverse host plants. However, chromosome-encoded determinants are also expected to play a role in spiroplasma biology. In S. citri, the chromosome sizes vary from 1.6 to 1.9 Mbp among strains (53, 54), and part of the size variation is thought to result from different amounts of prophage sequences (35). Many S. citri strains are infected by single-stranded DNA-containing filamentous phages (Plectrovirus), whose sequences also occur as partial or full-length prophages integrated into the spiroplasma chromosome (7, 35, 38). Here we report the partial chromosome sequence of S. citri strain GII3-3X and the functional assignment of the predicted coding sequences.