Low Fetal Weight is Directly Caused by Sequestration of Parasites and Indirectly by IL-17 and IL-10 Imbalance in the Placenta of Pregnant Mice with Malaria

The sequestration of infected erythrocytes in the placenta can activate the syncytiotrophoblast to release cytokines that affect the micro-environment and influence the delivery of nutrients and oxygen to fetus. The high level of IL-10 has been reported in the intervillous space and could prevent the pathological effects. There is still no data of Th17 involvement in the pathogenesis of placental malaria. This study was conducted to reveal the influence of placental IL-17 and IL-10 levels on fetal weights in malaria placenta. Seventeen pregnant BALB/C mice were divided into control (8 pregnant mice) and treatment group (9 pregnant mice infected by Plasmodium berghei). Placental specimens stained with hematoxylin and eosin were examined to determine the level of cytoadherence by counting the infected erythrocytes in the intervillous space of placenta. Levels of IL-17 and IL-10 in the placenta were measured using ELISA. All fetuses were weighed by analytical balance. Statistical analysis using Structural Equation Modeling showed that cytoadherence caused an increased level of placental IL-17 and a decreased level of placental IL-10. Cytoadherence also caused low fetal weight. The increased level of placental IL-17 caused low fetal weight, and interestingly low fetal weight was caused by a decrease of placental IL-10. It can be concluded that low fetal weight in placental malaria is directly caused by sequestration of the parasites and indirectly by the local imbalance of IL-17 and IL-10 levels.     

Acid phosphatase production by Aspergillus niger N402A in continuous flow culture

The production of acid phosphatases (E.C.3.1.3.2, ACPs) by Aspergillus niger N402A is regulated by specific growth rate, as well as phosphate availability and pH, as demonstrated by studies in continuous flow culture. Specific ACP activity was highest when A. niger was grown at pH 6.3 (64±8 U g⁻¹) or pH 2.8 (99±11 U g⁻¹), at a dilution rate of 0.07 h⁻¹ and phosphate concentrations below 0.46 mM. ACP production was growth correlated for specific growth rates between 0.07 and 0.13 h⁻¹. Four different ACPs, including two phytases, were produced by A. niger N402A. The ACP and the phytase with maximal activities at pH 5.5 were differentially expressed at different culture pH values, with greater production at low pH.     

Influence of Bacterial Lysate Quality on Growth of Two Bacterioplankton Species

All physico-chemical parameters that affect bacterial growth rate will also affect bacterial molecular composition, which in turn influences the chemical composition of bacterial lysate and its turnover rate in the ecosystem. To produce qualitatively different lysates, Vibrio sp. cells were grown under different pH, salt, or temperature conditions in rich growth media and then washed and lysed by autoclaving. Both the absolute concentrations and the ratios between elements in the lysates varied with different growth conditions, implying differences in lysate quality. Either Pseudoalteromonas sp. or Vibrio sp. was grown on the lysates at non-limiting lysate concentrations. Different lysates supported growth rates of Pseudoalteromonas sp. in the range from 0.25 to 1.53 h⁻¹. On the other hand, growth rates of Vibrio sp. grown on its own lysates were around 0.4 h⁻¹ and were not dependent on lysate quality. Two orders of magnitude decrease in Zn concentration in Vibrio sp. cells grown on different lysates as compared to cells grown on rich growth medium suggested that Zn might be a factor limiting growth. In the simple microbial loop studied, the initial difference in lysate quality was preserved in Pseudoalteromonas sp., whereas Vibrio sp. decreased the initial differences in lysate quality, thereby neutralizing the primary effect of environmental conditions on carbon turnover.     

Cloning,DNA sequence,and expression of Aeromonas caviae WS7b chitinase gene

A chitinase-producing bacterium, designated WS7b, was isolated from a soil sample obtained from a black-pepper plantation on Bangka Island, Indonesia. Fatty-acid methyl-ester analysis indicated that the isolate was Aeromonas caviae. A chitinase gene from WS7b was cloned in a pUC19-based plasmid vector, but without its natural promoter. The complete nucleotide sequence of the gene was determined, and the structural gene consisted of a 2748-bp region encoding 864 amino acids. DNA sequence analysis indicated that the gene had been cloned without its promoter, and this was confirmed by chitinase-plate assay of the truncated version of the gene in Escherichia coli. The chitinase gene product showed amino-acid sequence similarity to chiA from A. caviae. Chitinase enzyme activity was determined spectrophotometrically, using colloidal chitin azure as substrate for extracellular and intracellular fractions. The ability of the chitinase cloned in E. coli to hydrolyze chitin was less than that of the enzyme in its indigenous host.     

Ultrahigh density microarrays of solid samples

We present a sectioning and bonding technology to make ultrahigh density microarrays of solid samples, cutting edge matrix assembly (CEMA). Maximized array density is achieved by a scaffold-free, self-supporting construction with rectangular array features that are incrementally scalable. This platform technology facilitates arrays of >10,000 tissue features on a standard glass slide, inclusion of unique sample identifiers for improved manual or automated tracking, and oriented arraying of stratified or polarized samples.     

Pigment pattern evolution by differential deployment of neural crest and post-embryonic melanophore lineages in Danio fishes

Latent precursors or stem cells of neural crest origin are present in a variety of post-embryonic tissues. Although these cells are of biomedical interest for roles in human health and disease, their potential evolutionary significance has been underappreciated. As a first step towards elucidating the contributions of such cells to the evolution of vertebrate form, we investigated the relative roles of neural crest cells and post-embryonic latent precursors during the evolutionary diversification of adult pigment patterns in Danio fishes. These pigment patterns result from the numbers and arrangements of embryonic melanophores that are derived from embryonic neural crest cells, as well as from post-embryonic metamorphic melanophores that are derived from latent precursors of presumptive neural crest origin. In the zebrafish D. rerio, a pattern of melanophore stripes arises during the larval-to-adult transformation by the recruitment of metamorphic melanophores from latent precursors. Using a comparative approach in the context of new phylogenetic data, we show that adult pigment patterns in five additional species also arise from metamorphic melanophores, identifying this as an ancestral mode of adult pigment pattern development. By contrast, superficially similar adult stripes of D. nigrofasciatus (a sister species to D. rerio) arise by the reorganization of melanophores that differentiated at embryonic stages, with a diminished contribution from metamorphic melanophores. Genetic mosaic and molecular marker analyses reveal evolutionary changes that are extrinsic to D. nigrofasciatus melanophore lineages, including a dramatic reduction of metamorphic melanophore precursors. Finally, interspecific complementation tests identify a candidate genetic pathway for contributing to the evolutionary reduction in metamorphic melanophores and the increased contribution of early larval melanophores to D. nigrofasciatus adult pigment pattern development. These results demonstrate an important role for latent precursors in the diversification of pigment patterns across danios. More generally, differences in the deployment of post-embryonic neural crest-derived stem cells or their specified progeny may contribute substantially to the evolutionary diversification of adult form in vertebrates, particularly in species that undergo a metamorphosis.     

Survival and Epiphytic Fitness of a Nonpathogenic Mutant of Xanthomonas campestris pv. Glycines

Xanthomonas campestris pv. glycines is the causal agent of bacterial pustule disease of soybeans. The objective of this work was to construct a nonpathogenic mutant derived from the pathogenic wild-type strain YR32 and to evaluate its effectiveness in preventing growth of its parent on the soybean phyllosphere. A mini-Tn5-derived transposon was used to generate nonpathogenic mutants. Southern hybridization and pulsed-field gel electrophoresis confirmed the presence of a single transposon in each of the nonpathogenic mutants. One of the nonpathogenic mutants, M715, failed to induce a hypersensitive response in tomato leaves. An ice nucleation gene (inaZ) carried in pJL1703 was introduced into strain YR32 as a reporter gene to demonstrate that the presence of M715 could reduce colonization of the soybean phyllosphere by YR32. de Wit serial replacement analysis showed that M715 competed equally with its wild-type parental strain, YR32. Epiphytic fitness analysis of YR32 in the greenhouse indicated that the population dynamics of strains YR32, YR32(pJL1703), and M715 were similar, although the density of the mutant was slightly less than that of its parent. The M715 mutant was able to survive for 16 days after inoculation on soybean leaves and maintained population densities of approximately 10⁴ to 10⁵ cells g (fresh weight) of leaf⁻¹. Therefore, M715 shows promise as an effective biocontrol agent for bacterial pustule disease in soybeans.     

Do we need the third dimension? Quantifying the effect of the z-axis in 3D geometric morphometrics based on sailfin silversides (Telmatherinidae)

This study investigated the impact of the third dimension in geometric morphometrics (GM) using sailfin silversides (Telmatherinidae) from the Malili Lakes of Sulawesi (Indonesia). The three morphospecies of the monophyletic “roundfin” radiation are laterally compressed and vary in shape traits. The results of 2D and 3D GM were compared and quantified to discuss the advantages and disadvantages of both methods for closely related species and their sexes. This approach focused on the head because it is far more complex and three-dimensionally structured than the trunk or the caudal region. The results revealed no significant benefit concerning repeatability and measurement error in 3D GM compared to 2D GM. The z-axis contributed substantially to the variance of the 3D data set but was irrelevant for discrimination of species and sexes in the approach. Limited gain in information was contrasted by substantially higher effort for 3D compared to the 2D analyses. The study concluded that 2D GM is the more efficient shape analysis approach for discriminating roundfins. Broader studies are needed to test which of the two methods is more efficient in distinguishing laterally compressed fishes in general. For future studies, due to the high investment required, this study recommends carefully evaluating the necessity of 3D GM. If in doubt, this study suggests testing for congruence between 2D and 3D GM with a subsample and consequently applying 2D GM in the case of high congruence.     

Degradation of Root Community Traits as Indicator for Transformation of Tropical Lowland Rain Forests into Oil Palm and Rubber Plantations

Conversion of tropical forests into intensely managed plantations is a threat to ecosystem functions. On Sumatra, Indonesia, oil palm (Elaeis guineensis) plantations are rapidly expanding, displacing rain forests and extensively used rubber (Hevea brasiliensis) agro-forests. Here, we tested the influence of land use systems on root traits including chemical traits (carbon, nitrogen, mineral nutrients, potentially toxic elements [aluminium, iron] and performance traits (root mass, vitality, mycorrhizal colonization). Traits were measured as root community-weighed traits (RCWTs) in lowland rain forests, in rubber agro-forests mixed with rain forest trees, in rubber and oil palm plantations in two landscapes (Bukit Duabelas and Harapan, Sumatra). We hypothesized that RCWTs vary with land use system indicating increasing transformation intensity and loss of ecosystem functions. The main factors found to be related to increasing transformation intensity were declining root vitality and root sulfur, nitrogen, carbon, manganese concentrations and increasing root aluminium and iron concentrations as well as increasing spore densities of arbuscular mycorrhizas. Mycorrhizal abundance was high for arbuscular and low for ectomycorrhizas and unrelated to changes in RCWTs. The decline in RCWTs showed significant correlations with soil nitrogen, soil pH and litter carbon. Thus, our study uncovered a relationship between deteriorating root community traits and loss of ecosystem functionality and showed that increasing transformation intensity resulted in decreasing root nutrition and health. Based on these results we suggest that land management that improves root vitality may enhance the ecological functions of intense tropical production systems.