Three-dimensional organization of the brain and distribution of serotonin in the brain and ovary,and its effects on ovarian steroidogenesis in the giant freshwater prawn, <Emphasis Type="Italic">Macrobrachium rosenbergii</Emphasis>

The giant freshwater prawn, Macrobrachium rosenbergii, is an economically important crustacean species which has also been extensively used as a model in neuroscience research. The crustacean central nervous system is a highly complex structure, especially the brain. However, little information is available on the brain structure, especially the three-dimensional organization. In this study, we demonstrated the three-dimensional structure and histology of the brain of M. rosenbergii together with the distribution of serotonin (5-HT) in the brain and ovary as well as its effects on ovarian steroidogenesis. The brain of M. rosenbergii consists of three parts: protocerebrum, deutocerebrum and tritocerebrum. Histologically, protocerebrum comprises of neuronal clusters 6–8 and prominent anterior and posterior medial protocerebral neuropils (AMPN/PMPN). The protocerebrum is connected posteriorly to the deutocerebrum which consists of neuronal clusters 9–13, medial antenna I neuropil, a paired lateral antenna I neuropils and olfactory neuropils (ON). Tritocerebrum comprises of neuronal clusters 14–17 with prominent pairs of antenna II (AnN), tegumentary and columnar neuropils (CN). All neuronal clusters are paired structures except numbers 7, 13 and 17 which are single clusters located at the median zone. These neuronal clusters and neuropils are clearly shown in three-dimensional structure of the brain. 5-HT immunoreactivity (-ir) was mostly detected in the medium-sized neurons and neuronal fibers of clusters 6/7, 8, 9, 10 and 14/15 and in many neuropils of the brain including anterior/posterior medial protocerebral neuropils (AMPN/PMPN), protocerebral tract, protocerebral bridge, central body, olfactory neuropil (ON), antennal II neuropil (Ann) and columnar neuropil (CN). In the ovary, the 5-HT-ir was light in the oocyte step 1(Oc₁) and very intense in Oc₂–Oc₄. Using an in vitro assay of an explant of mature ovary, it was shown that 5-HT was able to enhance ovarian estradiol-17β (E₂) and progesterone (P₄) secretions. We suggest that 5-HT is specifically localized in specific brain areas and ovary of this prawn and it plays a pivotal role in ovarian maturation via the induction of female sex steroid secretions, in turn these steroids may enhance vitellogenesis resulting in oocyte growth and maturation.     

The production of ethanol plus fructose sweetener using fructose utilization negative mutants of Zymomonas mobilis

Summary Two mutants, unable to utilize fructose (Fru^–) as a sole source of carbon and energy, were isolated fromZymomonas mobilis following ethyl methane sulfonate (EMS) mutagenesis. The frequency of stable Fru^– mutants among survivors of mutagenesis was 1 in 10⁴. The two Fru^– mutants were able to cleave sucrose to glucose and fructose, and then ferment only the glucose to ethanol while accumulating fructose close to the theoretical value. Under controlled fermentation conditions, sucrose was converted to ethanol plus 80% or higher purity fructose syrup in a single-stage batch fermentation process, improving the Sucrotech Process significantly.     

Recognition and characterization of four Thai xylariaceous fungi inhabiting various tropical foliages as endophytes by DNA sequences and host plant preference

A total of 202 strains of xylariaceous fungi (183 endophytic strains isolated from 25 plant species of 24 genera in 21 families and 19 saprobic strains), segregated into four clades, were examined by nuclear rDNA internal transcribed spacer (ITS) sequence and beta-tubulin coding region analyses to clarify their taxonomic status and species boundaries. Three of the four species clades were assigned to Xylaria cubensis (100 strains), Xylaria grammica (33 strains), and Nemania diffusa (48 strains). Another fungus was tentatively assigned to Nemania cf. bipapillata (21 strains). Comparison of the host plants revealed that X. cubensis inhabited healthy leaves of at least 24 plant species (23 genera of 21 families) as endophytes; N. diffusa was found on 19 plant species (18 genera of 15 families), Nemania cf. bipapillata on 11 species (10 genera of 9 families), and X. grammica on 8 species (8 genera of 7 families). The present results suggest that the major xylariaceous endophytes in tropical plants are likely to be non-host specific, or have a wide range of host plant preferences.     

Comparison Between the Effect of Strongly and Weakly Cationic Exchange Resins on Matrix Physical Properties and the Controlled Release of Diphenhydramine Hydrochloride from Matrices

This study focused on investigating and comparing between the effect of the strongly cationic exchange resin, Dowex 88 (Dow88), and the weakly cationic exchange resin, Amberlite IRP64 (Am64), on the physical properties of matrices and their drug release profiles. The matrices were prepared by direct compression of Methocel K4M (HPMC) or Ethocel 7FP (EC) polymeric matrix formers and contained diphenhydramine hydrochloride as a model drug. The addition of Dow88 to the matrices decreased matrix hardness and increased thickness, diameter, and friability. In contrast, the addition of Am64 increased matrix hardness and maintained the original thickness, diameter, and friability. In deionized water, both resins lowered drug release from HPMC-based matrices by virtue of the gelation property of matrix former and the drug exchange property of embedded resin, in other words in situ resinate formation. Dow88 strongly dissociated and lowered the drug release to a greater extent than Am64, which was weakly dissociated. However, Am64 could retard drug release under simulated gastrointestinal conditions. EC-based matrices containing either resin displayed a propensity for disintegration caused by swelling and wicking (water adsorption) actions by the resin. The results of this study provided useful information on the utilization of ion exchange resins as release modifiers in matrix systems.     

Composition and localization of lipids in Penaeus merguiensis ovaries during the ovarian maturation cycle as revealed by imaging mass spectrometry

Ovary maturation, oocyte differentiation, and embryonic development in shrimp are highly dependent on nutritional lipids taken up by female broodstocks. These lipids are important as energy sources as well as for cell signaling. In this study, we report on the compositions of major lipids, i.e. phosphatidylcholines (PCs), triacylglycerols (TAGs), and fatty acids (FAs), in the ovaries of the banana shrimp, Penaeus merguiensis, during ovarian maturation. Thin-layer chromatography analysis showed that the total PC and TAG signal intensities increased during ovarian maturation. Further, by using gas chromatography, we found that (1) FAs 14:0, 16:1, 18:1, 18:2, 20:1, and 22:6 proportionally increased as ovarian development progressed to more mature stages; (2) FAs 16:0, 18:0, 20:4, and 20:5 proportionally decreased; and (3) FAs 15:0, 17:0, and 20:2 remained unchanged. By using imaging mass spectrometry, we found that PC 16:0/16:1 and TAG 18:1/18:2/22:6 were detected in oocytes stages 1 and 2. PCs 16:1/20:4, 16:0/22:6, 18:3/22:6, 18:1/22:6, 20:5/22:6, and 22:6/22:6 and TAGs 16:0/16:1/18:3, 16:0/18:1/18:3, 16:0/18:1/18:1, and 16:0/18:2/22:6 were present in all stages of oocytes. In contrast, the PC- and TAG-associated FAs 20:4, 20:5, and 22:6 showed high signal intensities in stage 3 and 4 oocytes. These FAs may act as nutrition sources as well as signaling molecules for developing embryos and the hatching process. Knowledge of lipid compositions and localization could be helpful for formulating the diet for female broodstocks to promote fecundity and larval production.     

A novel pathogenic mechanism of highly pathogenic avian influenza H5N1 viruses involves hemagglutinin mediated resistance to serum innate inhibitors

In this study, the effect of innate serum inhibitors on influenza virus infection was addressed. Seasonal influenza A(H1N1) and A(H3N2), 2009 pandemic A(H1N1) (H1N1pdm) and highly pathogenic avian influenza (HPAI) A(H5N1) viruses were tested with guinea pig sera negative for antibodies against all of these viruses as evaluated by hemagglutination-inhibition and microneutralization assays. In the presence of serum inhibitors, the infection by each virus was inhibited differently as measured by the amount of viral nucleoprotein produced in Madin-Darby canine kidney cells. The serum inhibitors inhibited seasonal influenza A(H3N2) virus the most, while the effect was less in seasonal influenza A(H1N1) and H1N1pdm viruses. The suppression by serum inhibitors could be reduced by heat inactivation or treatment with receptor destroying enzyme. In contrast, all H5N1 strains tested were resistant to serum inhibitors. To determine which structure (hemagglutinin (HA) and/or neuraminidase (NA)) on the virus particles that provided the resistance, reverse genetics (rg) was applied to construct chimeric recombinant viruses from A/Puerto Rico/8/1934(H1N1) (PR8) plasmid vectors. rgPR8-H5 HA and rgPR8-H5 HANA were resistant to serum inhibitors while rgPR8-H5 NA and PR8 A(H1N1) parental viruses were sensitive, suggesting that HA of HPAI H5N1 viruses bestowed viral resistance to serum inhibition. These results suggested that the ability to resist serum inhibition might enable the viremic H5N1 viruses to disseminate to distal end organs. The present study also analyzed for correlation between susceptibility to serum inhibitors and number of glycosylation sites present on the globular heads of HA and NA. H3N2 viruses, the subtype with highest susceptibility to serum inhibitors, harbored the highest number of glycosylation sites on the HA globular head. However, this positive correlation cannot be drawn for the other influenza subtypes.     

Fabrication and In Vitro/In Vivo Performance of Mucoadhesive Electrospun Nanofiber Mats Containing α-Mangostin

This study aimed to fabricate mucoadhesive electrospun nanofiber mats containing α-mangostin for the maintenance of oral hygiene and reduction of the bacterial growth that causes dental caries. Synthesized thiolated chitosan (CS-SH) blended with polyvinyl alcohol (PVA) was selected as the mucoadhesive polymer. α-Mangostin was incorporated into the CS-SH/PVA solution and electrospun to obtain nanofiber mats. Scanning electron microscopy, differential scanning calorimetry, X-ray diffraction, and tensile strength testing were used to characterize the mats. The swelling degree and mucoadhesion were also determined. The nanofiber mats were further evaluated regarding their α-mangostin content, in vitro α-mangostin release, antibacterial activity, cytotoxicity, in vivo performance, and stability. The results indicated that the mats were in the nanometer range. The α-mangostin was well incorporated into the mats, with an amorphous form. The mats showed suitable tensile strength, swelling, and mucoadhesive properties. The loading capacity increased when the initial amount of α-mangostin was increased. Rapid release of α-mangostin from the mats was achieved. Additionally, a fast bacterial killing rate occurred at the lowest concentration of nanofiber mats when α-mangostin was added to the mats. The mats were less cytotoxic after use for 72 h. Moreover, in vivo testing indicated that the mats could reduce the number of oral bacteria, with a good mouth feel. The mats maintained the amount of α-mangostin for 6 months. The results suggest that α-mangostin-loaded mucoadhesive electrospun nanofiber mats may be a promising material for oral care and the prevention of dental caries.KEY WORDS: dental caries, mucoadhesive property, nanofibers, thiolated chitosan, α-mangostin     

Chromone derivatives from the wood-decay fungus Rhizina sp. BCC 12292

A new chromone derivative (1), together with the known oxepino[2,3-b]chromones, microsphaeropsones A (2) and B (3), and xanthopinone (4), was isolated from the wood-decay fungus Rhizina sp. BCC 12292. The structure of 1 was elucidated on the basis of NMR spectroscopic and mass spectrometry data. Transformation of 4 into 1 occurred when a solution of 4 in MeOH was treated with p-TsOH or silica gel, which strongly suggested that 1 may be an artifact formed during the processing of the extract. Compound 1 exhibited antimalarial activity with an IC₅₀ of 5.1 μg/ml and cytotoxic activities against NCI-H187 and Vero cell lines with respective IC₅₀ of 6.4 and 1.6 μg/ml.     

Lepraric acid derivatives as chemotaxonomic markers in Hypoxylon aeruginosum, Chlorostroma subcubisporum and C. cyaninum, sp. nov

Hypoxylon aeruginosum (Xylariaceae), an infrequently encountered predominantly tropical pyrenomycete, of which two varieties are known to science, is characterised by having a cyan blue stromatal surface or subsurface. In the course of our ongoing chemotaxonomic evaluation of the Xylariaceae, specific profiles of H. aeruginosum were observed by high performance liquid chromatography, coupled with diode array detection and mass spectrometry (hplc-DAD/MS). By comparison with an authentic standard, lepraric acid and several yet unidentified metabolites with similar hplc-DAD/MS characteristics were detected in the stromata of the type material and other specimens of this species. Interestingly, lepraric acid was hitherto only known from lichenised ascomycetes. Hypoxylon aeruginosum, which is here reported first from Africa and Asia, contained none of the metabolites that were previously detected in other Xylariaceae, except for stromata growing hyperparasitically on other Hypoxylon species. A different lepraric acid derivative was also detected in the type specimen of Chlorostroma subcubisporum, which differs from H. aeruginosum by having a green stromatal surface, cuboid ascospores, and in lacking an amyloid ascal apical apparatus. A second species of Chlorostroma, which showed essentially the same metabolite profile as H. aeruginosum, is described from Thailand. We conclude that Chlorostroma and H. aeruginosum are closely related. However, no taxonomic conclusions are drawn from these findings because no cultures have so far become available to study their anamorphic morphology, their secondary metabolites in culture, and their molecular phylogeny. Taxonomic novelty: Chlorostroma cyaninum L?ss?e, Srikitikulchai & J. Fournier, sp. nov.