Phylogenetic Evidence That Two Distinct Trichuris Genotypes Infect both Humans and Non-Human Primates

Although there has been extensive debate about whether Trichuris suis and Trichuris trichiura are separate species, only one species of the whipworm T. trichiura has been considered to infect humans and non-human primates. In order to investigate potential cross infection of Trichuris sp. between baboons and humans in the Cape Peninsula, South Africa, we sequenced the ITS1-5.8S-ITS2 region of adult Trichuris sp. worms isolated from five baboons from three different troops, namely the Cape Peninsula troop, Groot Olifantsbos troop and Da Gama Park troop. This region was also sequenced from T. trichiura isolated from a human patient from central Africa (Cameroon) for comparison. By combining this dataset with Genbank records for Trichuris isolated from other humans, non-human primates and pigs from several different countries in Europe, Asia, and Africa, we confirmed the identification of two distinct Trichuris genotypes that infect primates. Trichuris sp. isolated from the Peninsula baboons fell into two distinct clades that were found to also infect human patients from Cameroon, Uganda and Jamaica (named the CP-GOB clade) and China, Thailand, the Czech Republic, and Uganda (named the DG clade), respectively. The divergence of these Trichuris clades is ancient and precedes the diversification of T. suis which clustered closely to the CP-GOB clade. The identification of two distinct Trichuris genotypes infecting both humans and non-human primates is important for the ongoing treatment of Trichuris which is estimated to infect 600 million people worldwide. Currently baboons in the Cape Peninsula, which visit urban areas, provide a constant risk of infection to local communities. A reduction in spatial overlap between humans and baboons is thus an important measure to reduce both cross-transmission and zoonoses of helminthes in Southern Africa.     

Olfactory behavior and response of household ants (Hymenoptera) to different types of coffee odor: A coffee-based bait development prospect

Odor sensation is a sensory modality of considerable significance in the foraging behavior and interactional organization of ants. In the food bait technology, smell is the basis of attraction, which, in turn, is the line of bait use and a key parameter for judging efficacy. Yet, the currently available baits possess low attractiveness to many ant pests. Hence, strategies to produce ant bait with increased attractiveness are needed. Despite evidence that coffee has a diverse aroma complex that affects the behavior of honey bees and ants, its attraction to house-invading ants has yet to be investigated. In a series of Y-tube olfactometer bioassays, we examined the behavioral responses of Tapinoma indicum (TI), Monomorium pharaonis (MP) and Solenopsis geminata (SG) to various coffee-induced odor stimuli, comprised of extracts from Arabica, Robusta and Liberica. All coffee extracts showed an influence on the behavior of TI, MP and SG workers, with Arabica showed the most significant influence to the tested ants. The workers of TI, MP and SG were more attracted to the odor of 0.01% Arabica extract (ONE), in comparison with 0.05% Arabica extract (TWO) or 0.10% Arabica extract (THREE). Arabica extract mixed with sugar (S) elicited a significant attraction from workers of all three species in a balanced competition with either unsweetened Arabica extract or water. These results indicated that coffee, particularly Arabica, was attractive to the foragers of TI, MP and SG, thus, the use of coffee as a novel stimulus agent seems plausible in ant bait development.     

A porous medium‐chain‐length poly(3‐hydroxyalkanoates)/hydroxyapatite composite as scaffold for bone tissue engineering

Polyhydroxyalkanoates (PHA) are hydrophobic biopolymers with huge potential for biomedical applications due to their biocompatibility, excellent mechanical properties and biodegradability. A porous composite scaffold made of medium‐chain‐length poly(3‐hydroxyalkanoates) (mcl‐PHA) and hydroxyapatite (HA) was fabricated using particulate leaching technique and NaCl as a porogen. Different percentages of HA loading was investigated that would support the growth of osteoblast cells. Ultrasonic irradiation was applied to facilitate the dispersion of HA particles into the mcl‐PHA matrix. The different P(3HO‐co‐3HHX)/HA composites were investigated using field emission scanning electron microscopy (FESEM), X‐ray diffraction (XRD) and energy dispersive X‐ray analysis (EDXA). The scaffolds were found to be highly porous with interconnecting pore structures and the HA particles were homogeneously dispersed in the polymer matrix. The scaffolds biocompatibility and osteoconductivity were also assessed following the proliferation and differentiation of osteoblast cells on the scaffolds. From the results, it is clear that scaffolds made from P(3HO‐co‐3HHX)/HA composites are viable candidate materials for bone tissue engineering applications.     

The Missing Link in Plant Histidine Biosynthesis: Arabidopsis myoinositol monophosphatase-like2 Encodes a Functional Histidinol-Phosphate Phosphatase

Histidine (His) plays a critical role in plant growth and development, both as one of the standard amino acids in proteins, and as a metal-binding ligand. While genes encoding seven of the eight enzymes in the pathway of His biosynthesis have been characterized from a number of plant species, the identity of the enzyme catalyzing the dephosphorylation of histidinol-phosphate to histidinol has remained elusive. Recently, members of a novel family of histidinol-phosphate phosphatase proteins, displaying significant sequence similarity to known myoinositol monophosphatases (IMPs) have been identified from several Actinobacteria. Here we demonstrate that a member of the IMP family from Arabidopsis (Arabidopsis thaliana), myoinositol monophosphatase-like2 (IMPL2; encoded by At4g39120), has histidinol-phosphate phosphatase activity. Heterologous expression of IMPL2, but not the related IMPL1 protein, was sufficient to rescue the His auxotrophy of a Streptomyces coelicolor hisN mutant. Homozygous null impl2 Arabidopsis mutants displayed embryonic lethality, which could be rescued by supplying plants heterozygous for null impl2 alleles with His. In common with the previously characterized HISN genes from Arabidopsis, IMPL2 was expressed in all plant tissues and throughout development, and an IMPL2:green fluorescent protein fusion protein was targeted to the plastid, where His biosynthesis occurs in plants. Our data demonstrate that IMPL2 is the HISN7 gene product, and suggest a lack of genetic redundancy at this metabolic step in Arabidopsis, which is characteristic of the His biosynthetic pathway.His is one of the standard 20 amino acids found in proteins, and is required for plant growth and development (Muralla et al., 2007; Bikard et al., 2009). The occurrence of His in the active sites of numerous enzymes is attributable to the imidazole functional group (pK_a approximately 6), which can alternate between the protonated and unprotonated states under physiologically relevant conditions, allowing its participation in acid-base catalysis (Fersht, 1999). His also plays important biochemical roles as a nucleophile in phosphoryl group transfer, and as a metal-binding ligand (Fraústo da Silva and Williams, 2001; Harding, 2004).Genetic analysis of His biosynthesis has provided insights into key regulatory mechanisms in microorganisms, notably the discovery of operon structure and metabolic regulation through attenuation (Ames et al., 1960; Roth and Ames, 1966). However, this was the last amino acid biosynthetic pathway to be characterized in plants, and only recently has it been demonstrated that His biosynthesis follows the same route as that in microorganisms with 10 reactions catalyzed by eight enzymes (Fig. 1), beginning with the condensation of ATP and 5-phosphoribosyl-1-pyrophosphate catalyzed by the enzyme ATP-phosphoribosyl transferase (Ohta et al., 2000). His biosynthesis is linked to purine metabolism through its precursors 5-phosphoribosyl-1-pyrophosphate and ATP, and the release of an intermediate (5′-phosphoribosyl-4-carboxamide-5-aminoimidazole) at the branch point step catalyzed by imidazole-glycerol phosphate synthase, which enters the de novo purine synthesis pathway (Alifano et al., 1996; Ward and Ohta, 1999). While the regulation of His biosynthesis has not been as comprehensively investigated in plants as it has in microorganisms, analysis of transgenic Arabidopsis (Arabidopsis thaliana) plants overexpressing single HISN genes under the control of the cauliflower mosaic virus 35S promoter suggests that ATP-phosphoribosyl transferase activity controls the size of the pool of free His in plants (Ingle et al., 2005; Rees et al., 2009).Open in a separate windowFigure 1.The His biosynthetic pathway in plants. Abbreviations used for enzyme names in this work are shown in parentheses, and enzyme commission numbers and Arabidopsis gene loci indicated. Modified after Ward and Ohta (1999), Ingle et al. (2005), and Muralla et al. (2007).Genes encoding seven of the eight enzymes in the His pathway were identified in plants during the late 1990s (Nagai et al., 1993; Mori et al., 1995; El Malki et al., 1998; Fujimori and Ohta, 1998a, 1998b; Fujimori et al., 1998; Ohta et al., 2000) and, in contrast to most other amino acid biosynthetic pathways, the majority were found to be encoded by single genes in the Arabidopsis genome (Stepansky and Leustek, 2006). The missing link in the pathway has been HISN7, histidinol-phosphate phosphatase (HPP; EC 3.1.3.15). While dephosphorylation of histidinol-P to histidinol was first detected in plant extracts almost 40 years ago (Wiater et al., 1971), the identity of the enzyme(s) catalyzing this reaction in plants is unknown. HPP proteins identified from microorganisms prior to 2006 can be grouped into one of two superfamilies—the DDDD (which contain four invariant Asp residues) and PHP (polymerase and histidinol phosphatase) superfamilies (Lee et al., 2008). The DDDD superfamily contains bifunctional enzymes from enteric bacteria (such as Escherichia coli) where dephosphorylation of histidinol-P is catalyzed by the N-terminal domain, while the C terminus displays imidazole glycerol-phosphate dehydratase (IGPD) activity (Alifano et al., 1996; Fani et al., 2007), and monofuctional HPP proteins such as that recently identified in Thermococcus onnurineus (Lee et al., 2008). In contrast, all members of the PHP family identified to date are monofunctional HPP enzymes, including those encoded by HIS2 in Saccharomyces cerevisiae and ytvP in Bacillus subtilis (Alifano et al., 1996; le Coq et al., 1999). Notably, neither the Arabidopsis nor rice (Oryza sativa) genomes contain any sequences with significant sequence identity to members of either the DDDD or PHP superfamilies (Stepansky and Leustek, 2006).A novel HPP protein, showing no sequence similarity to members of either the DDDD or PHP superfamilies, was recently isolated from Corynebacterium glutamicum (Mormann et al., 2006), and orthologs have subsequently been identified in other Actinobacteria, including Streptomyces coelicolor (Marineo et al., 2008). All members of this new family display significant sequence similarity to known myoinositol monophosphatases (IMPs; Mormann et al., 2006), which catalyze the hydrolysis of the ester bond of d-myoinositol 1(or 3)-P (d-Ins 1-P, d-Ins 3-P) to generate myoinositol, without the production of a phospho-enzyme intermediate (Leech et al., 1993). In eukaryotes, myoinositol plays a crucial role in a number of cellular processes including phosphatidylinositol-mediated signaling and the membrane anchoring of proteins (Boss et al., 2006; Fujita and Jigami, 2008). To date, three putative IMP encoding sequences have been identified in the Arabidopsis genome: VTC4 (At3g02870), myoinositol monophosphatase-like1 (IMPL1; At1g31190), and IMPL2 (At4g39120; Torabinejad et al., 2009). VTC4 was first reported as the l-Gal 1-P phosphatase in ascorbate biosynthesis in Arabidopsis (Laing et al., 2004; Conklin et al., 2006), but was recently demonstrated to be a bifunctional enzyme also able to catalyze the dephosphorylation of d-Ins 1-P and d-Ins 3-P to myoinositol in vitro (Torabinejad et al., 2009). vtc4 null mutants showed only a 30% reduction in myoinositol content, suggesting genetic redundancy in the capacity to generate myoinositol, and accordingly IMPL1 and IMPL2 were shown to have in vitro IMP activity (Torabinejad et al., 2009). Both enzymes were also able to utilize l-Gal 1-P as a substrate, suggesting some promiscuity in their substrate specificity. Here we demonstrate that the IMPL2 protein encoded by At4g39120 is also able to catalyze the dephosphorylation of histidinol-P to histidinol, completing the His biosynthetic pathway in plants.     

Regulating the molar fraction of 4-hydroxybutyrate in Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) by biological fermentation and enzymatic degradation

The regulation of 4-hydroxybutyrate (4HB) molar fraction in the poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] of a local isolate Cupriavidus sp. USMAA1020 was attempted by employing a feeding strategy through fed-batch fermentation in 100-L fermenter. The growth of Cupriavidus sp. USMAA1020 was enhanced by frequently feeding carbon and nitrogen at a ratio of 5 (C/N 5) using a DO-stat with cascade mode at 20% (v/v) dissolved oxygen (DO). The feeding of C/N 5 and the use of the DO-stat mode were able to regulate the 4HB composition from 0–67 mol% by sequential feeding of γ-butyrolactone and supplementing oleic acid. A high 4HB molar fraction of 67 mol% with a PHA concentration of 5.2 g/L was successfully obtained by employing this feeding strategy. Notably, enzymatic degradation carried out enhanced the 4HB composition of the copolymer synthesized. PHB depolymerase enzyme from Acidovorax sp. was used to degrade this P(3HB-co-70-mol%4HB) copolymer and the 4HB composition could be increased up to 83 mol%. The degradation process was observed by monitoring the time-dependent change in the weight loss of copolymer films. The percentage of weight loss of solvent-cast film increased proportionally up to 19% within 3 h, whereas salt-leached films showed 90% of weight loss within 3 h of incubation and were completely degraded by 4 h. The molecular weight (M _n ) of the films treated with enzyme demonstrated a slight decrease. SEM observation exhibited a rough surface morphology of the copolymer degraded with depolymerase enzyme.     

A novel function for a redox-related LEA protein (SAG21/AtLEA5) in root development and biotic stress responses

SAG21/AtLEA5 belongs to the late embryogenesis-associated (LEA) protein family. Although it has been implicated in growth and redox responses, its precise roles remain obscure. To address this problem, we characterized root and shoot development and response to biotic stress in SAG21/AtLEA5 over-expressor (OEX) and antisense (AS) lines. AS lines exhibited earlier flowering and senescence and reduced shoot biomass. Primary root length was reduced in AS lines, as was the number of laterals relative to the primary root. Root hair number was unchanged but root hair length was proportional to SAG21/AtLEA5 expression level, with longer root hairs in OEX lines and shorter root hairs in AS, relative to wild type. Growth of the fungal nectroph, Botrytis cinerea and of a virulent bacterial pathogen (Pseudomonas syringae pv. tomato) was affected by SAG21/AtLEA5 expression; however, growth of an avirulent P.syringae strain was unaffected. A SAG21/AtLEA5-YFP fusion was localized to mitochondria, raising the intriguing possibility that SAG21 interacts with proteins involved in mitochondrial ROS signalling, which in turn, impacts on root development and pathogen responses.     

Ecological factors affecting host plant and shelter preferences of Tetraponera rufonigra (Hymenoptera: Formicidae) in urban ecosystem

Host-plant preferences of Tetraponera rufonigra Jerdon (Hymenoptera: Formicidae) were assessed by field measurement in relation to the types of trash found in the surrounding tree perimeters. The correlations between the density of T. rufonigra and the plants (types of trash and levels of infestation) were determined based on the data gathered at 34 study sites in the Eastern part of the Penang Island to clarify the density differences of T. rufonigra among the sites. A simple linear regression analysis was also employed to assess the effects of environmental parameters i.e. UV light, temperature and humidity on the density of T. rufonigra. No significant difference was found between the infestation level at each site and the types of trash. Six species were identified as host-plant preferences of T. rufonigra i.e. Cassia fistula L., Azadirachta indica A. Juss., Mimusops elengi L., Delonix regia (Hook), Cerberra odollam Gaertn and Tabebuia rosea (Bertol.). These tree species were recorded for the first time as the most preferred host trees by T. rufonigra in Malaysia. The results also identified that T. rufonigra preferred the trees with high humidity level, suitable surrounding temperature and UV light as their habitats.