A study on the energy source in the developing embryo of the mangrove horseshoe crab,Carcinoscorpius rotundicauda (Latreille)

The mangrove horseshoe crab, Carcinoscorpius rotundicauda, is an Asian species found in Malaysia. This ancient arthropod has a long incubational period during which it depends on various energy sources for both embryogenesis and organogenesis. This study describes the trend of energy utilization from the endogenous reserves by the developing embryos from 0 to 40 days of incubation (until the hatching of the larvae). The dry weight, insoluble protein, carbohydrate, glycogen and lipid showed a declining trend from 0 to 40 days of incubation, whereas the wet weight, water content, ash content and soluble protein showed an increasing trend. Selected micro-elements such as Cu²⁺, Fe²⁺ and Zn²⁺ also demonstrated an interesting trend in the developing eggs when the egg mass was subjected to inductively coupled plasma mass spectrometry analysis, where these elements showed a high correlation with the moulting stages and egg development. Maximum variations within the micro-elements were observed during the 1st (10 days after fertilization) and 2nd (35–36 days after fertilization) moulting stages within the developing eggs. This study clearly indicated that the moulting cycles of C. rotundicauda during embryonic development influence energy utilization in the form of carbohydrates, lipids, proteins, glycogen and other micro-elements.     

Unmasking Heavily O-Glycosylated Serum Proteins Using Perchloric Acid: Identification of Serum Proteoglycan 4 and Protease C1 Inhibitor as Molecular Indicators for Screening of Breast Cancer

Heavily glycosylated mucin glycopeptides such as CA 27.29 and CA 15–3 are currently being used as biomarkers for detection and monitoring of breast cancer. However, they are not well detected at the early stages of the cancer. In the present study, perchloric acid (PCA) was used to enhance detection of mucin-type O-glycosylated proteins in the serum in an attempt to identify new biomarkers for early stage breast cancer. Sensitivity and specificity of an earlier developed sandwich enzyme-linked lectin assay were significantly improved with the use of serum PCA isolates. When a pilot case-control study was performed using the serum PCA isolates of normal participants (n = 105) and patients with stage 0 (n = 31) and stage I (n = 48) breast cancer, higher levels of total O-glycosylated proteins in sera of both groups of early stage breast cancer patients compared to the normal control women were demonstrated. Further analysis by gel-based proteomics detected significant inverse altered abundance of proteoglycan 4 and plasma protease C1 inhibitor in both the early stages of breast cancer patients compared to the controls. Our data suggests that the ratio of serum proteoglycan 4 to protease C1 inhibitor may be used for screening of early breast cancer although this requires further validation in clinically representative populations.     

Evidence of foliar aluminium accumulation in local, regional and global datasets of wild plants

? High foliar concentrations of aluminium (Al) have been reported in numerous plant species, but progress on the understanding of the functional significance of this trait is constrained by the absence of a quantitative analysis of its distribution among plant lineages and across biomes. ? We constructed a global dataset of foliar Al and nutrient concentrations for 1044 plant species from literature sources and new data collections in Brunei Darussalam. ? Our results provide statistical support for the existence of Al accumulators and non-Al accumulators in global, regional and local floras based on foliar Al concentrations. A value of 1 mg Al g(-1) leaf dry mass is a suitable threshold to distinguish between these two groups in a sample of species that lacks any geographical reference. However, a higher threshold foliar Al concentration is required to distinguish between Al accumulators in tropical (2.3-3.9 mg Al g(-1) leaf dry mass) than in temperate (1.1 mg Al g(-1) leaf dry mass) floras. There was a phylogenetic signal in the foliar concentrations of Al, but phylogeny did not explain the difference in the mean foliar Al concentration between tropical and temperate floras in a phylogenetically controlled analysis. ? Phylogeny and soil chemistry are potential factors driving Al accumulation in certain groups of plants.     

Rapid Fishery Assessment by Market Survey (RFAMS) – An Improved Rapid-Assessment Approach to Characterising Fish Landings in Developing Countries

The complex multi-gear, multi-species tropical fisheries in developing countries are poorly understood and characterising the landings from these fisheries is often impossible using conventional approaches. A rapid assessment method for characterising landings at fish markets, using an index of abundance and estimated weight within taxonomic groups, is described. This approach was developed for contexts where there are no detailed data collection protocols, and where consistent data collection across a wide range of fisheries types and geographic areas is required, regardless of the size of the site and scale of the landings. This methodology, which was demonstrated at seven fish landing sites/fish markets in southern Indonesia between July 2008 and January 2011, provides a rapid assessment of the abundance and diversity in the wild catch over a wide variety of taxonomic groups. The approach has wider application for species-rich fisheries in developing countries where there is an urgent need for better data collection protocols, monitoring future changes in market demographics, and evaluating health of fisheries.     

Host specific variation in photosynthesis of an obligate xylem‐tapping mistletoe Dendrophthoe curvata in a Bornean heath forest

Most mistletoe–host ecophysiological studies have paid attention to the influence of parasites on host performance. This paper explored the impact of varying hosts on the photosynthesis of a single mistletoe species. Here, we studied an obligate xylem‐tapping tropical mistletoe (Dendrophthoe curvata (Blume) Miquel) parasitizing four different hosts (Acacia auriculiformis A. Cunn. Ex Benth, Andira inermis (W. Wright) DC., Mangifera indica L. and Vitex pinnata L.) in a homo geneous tropical heath forest patch in Brunei Darussalam. We compared photosynthetic capacity and photosynthesis‐related characteristics of the mistletoe on four different hosts to evaluate the overall impact of hosts on the parasite. Results showed that the mistletoe–host patterns of CO₂ assimilation rates, transpiration rates and water use efficiency varied significantly based on the host. In the D. curvata–Vitex pinnata association, the mistletoe exhibited significantly lower CO₂ assimilation rates but showed no significant variations in transpiration rates and water use efficiency when compared to the host. In D. curvata–Andira inermis and D. curvata–Mangifera indica associations, the mistletoe showed significantly higher photosynthetic rates than the hosts, whereas in the D. curvata–Acacia auriculiformis association, there was no significant difference in photosynthetic rates between the counterparts. Host specificity also significantly influenced some mistletoe photosynthetic parameters such as light saturated photosynthesis, specific leaf area, leaf chlorophyll content, CO₂ assimilation rates, stomatal conductance, transpiration rates and water use efficiency. Different tree hosts intrinsically offer different resources to their obligate mistletoe parasites based on their physiology and environmental parameters. We argue that host‐specific responses have driven these intra‐specific variations in mistletoe physiology. This study provides background for future investigation on potential host‐regulated mechanisms that drive functional changes in host‐dependent mistletoes.     

A mutant <Emphasis Type="SmallCaps">l</Emphasis>-asparaginase II signal peptide improves the secretion of recombinant cyclodextrin glucanotransferase and the viability of <Emphasis Type="Italic">Escherichia coli</Emphasis>

l-Asparaginase II signal peptide was used for the secretion of recombinant cyclodextrin glucanotransferase (CGTase) into the periplasmic space of E. coli. Despite its predominant localisation in the periplasm, CGTase activity was also detected in the extracellular medium, followed by cell lysis. Five mutant signal peptides were constructed to improve the periplasmic levels of CGTase. N1R3 is a mutated signal peptide with the number of positively charged amino acid residues in the n-region increased to a net charge of +5. This mutant peptide produced a 1.7-fold enhancement of CGTase activity in the periplasm and significantly decreased cell lysis to 7.8% of the wild-type level. The formation of intracellular inclusion bodies was also reduced when this mutated signal peptide was used as judged by SDS–PAGE. Therefore, these results provide evidence of a cost-effective means of expression of recombinant proteins in E. coli.     

Quaternary structure of SecA in solution and bound to SecYEG probed at the single molecule level

Dual-color fluorescence-burst analysis (DCFBA) was applied to measure the quaternary structure and high-affinity binding of the bacterial motor protein SecA to the protein-conducting channel SecYEG reconstituted into lipid vesicles. DCFBA is an equilibrium technique that enables the direct observation and quantification of protein-protein interactions at the single molecule level. SecA binds to SecYEG as a dimer with a nucleotide- and preprotein-dependent dissociation constant. One of the SecA protomers binds SecYEG in a salt-resistant manner, whereas binding of the second protomer is salt sensitive. Because protein translocation is salt sensitive, we conclude that the dimeric state of SecA is required for protein translocation. A structural model for the dimeric assembly of SecA while bound to SecYEG is proposed based on the crystal structures of the Thermotoga maritima SecA-SecYEG and the Escherichia coli SecA dimer.     

17beta-Estradiol supplementation reduces tubulointerstitial fibrosis by increasing MMP activity in the diabetic kidney

We previously reported that supplementation with 17beta-estradiol (E2) attenuates albuminuria, glomerulosclerosis, and tubulointerstitial fibrosis in diabetic nephropathy. The present study examined the mechanisms by which E2 regulates extracellular matrix (ECM) metabolism, a process that contributes to the development of glomerulosclerosis and tubulointerstitial fibrosis. The study was performed in female nondiabetic (ND), streptozotocin-induced diabetic (D), and diabetic with E2 supplementation (D+E2) Sprague-Dawley rats for 12 wk. Diabetes was associated with an increase in the renal expression of collagen alpha type IV [ND, 0.22 +/- 0.02; D, 0.99 +/- 0.09 relative optical density (ROD); P < 0.05] and fibronectin protein (ND, 0.36 +/- 0.08; D, 1.47 +/- 0.08 ROD; P < 0.05), as measured by Western blot analysis. E2 supplementation partially attenuated this increase in collagen alpha type IV (D+E2, 0.47 +/- 0.10 ROD) and fibronectin (D+E2, 0.71 +/- 0.16 ROD) protein expression associated with D. Diabetes was also associated with a decrease in the expression of matrix metalloproteinase (MMP) isoform MMP-2 (ND, 0.79 +/- 0.01; D, 0.62 +/- 0.06 ROD; P < 0.05) and MMP-9 protein (ND, 0.49 +/- 0.02; D, 0.33 +/- 0.03 ROD; P < 0.05). E2 supplementation restored MMP-2 and MMP-9 protein to levels similar or even greater than in the ND kidneys (MMP-2, 0.75 +/- 0.06; MMP-9, 0.73 +/- 0.01 ROD). The activities of MMP-2 (ND, 7.88 +/- 0.44; D, 5.60 +/- 0.54 ROD; P < 0.05) and MMP-9 (ND, 29.9 +/- 1.8; D, 12.9 +/- 2.3 ROD; P < 0.05), as measured by zymography, were also decreased with D. E2 supplementation restored MMP-2 and MMP-9 activity to levels similar to that in ND kidneys (MMP-2, 7.66 +/- 0.35; MMP-9, 21.4 +/- 2.9 ROD). We conclude that E2 supplementation is renoprotective by attenuating glomerulosclerosis and tubulointerstitial fibrosis by reducing ECM synthesis and increasing ECM degradation.