Rapidly diminishing mangrove forests in Myanmar (Burma): a review

IPCC predictions indicate an increase in temperatures by 1.5–7°C in some Amazonian regions during the twenty-first century. These changes could disrupt the present distribution patterns of organisms, including wetland plant species. In this work, we determined in microcosms the effects of scenarios combining elevated temperature and atmospheric CO₂ concentration on the germination and initial growth of the arborescent Amazonian aquatic macrophyte Montrichardia arborescens. Seeds were germinated, and seedlings produced were monitored over a 5-month period in four microcosms: Control: ambient temperature and CO₂ level; Mild: Control + 1.5°C and + 200 ppm CO₂; intermediate: control + 2.5°C and + 400 ppm CO₂; Extreme: Control + 4.5°C and + 850 ppm of CO₂. Rapid light response curves and Fv/Fm values taken in seedlings showed a decrease in electron transportation rate with CO₂ and temperature elevation. Mild and Intermediate treatments stimulated biomass production; Extreme treatment and Control produced similar results. The severe climatic changes expected in the future may negatively influence carbon accumulation in M. arborescens. Since aquatic macrophytes in Amazonian wetlands and wetlands worldwide are key plant species, further studies are needed to predict their fate in a global change perspective.     

Silvorchis vietnamica (Orchidaceae,Orchidoideae, Vietorchidinae), a new miniature mycotrophic species from southern Vietnam

A second species of Silvorchis, until now considered to be a presumably extinct monotypic genus endemic to western Java has been discovered in southern Vietnam. The species, here named as S. vietnamica, is described and illustrated, with data on its distribution, ecology, phenology and estimated conservation status. A key for identification of the two known species of the genus is also provided. The taxonomic affinities and phylogenetic placement of the newly discovered plant are briefly discussed.     

Identifying outlier loci in admixed and in continuous populations using ancestral population differentiation statistics

Finding genetic signatures of local adaptation is of great interest for many population genetic studies. Common approaches to sorting selective loci from their genomic background focus on the extreme values of the fixation index, F_ST, across loci. However, the computation of the fixation index becomes challenging when the population is genetically continuous, when predefining subpopulations is a difficult task, and in the presence of admixed individuals in the sample. In this study, we present a new method to identify loci under selection based on an extension of the F_ST statistic to samples with admixed individuals. In our approach, F_ST values are computed from the ancestry coefficients obtained with ancestry estimation programs. More specifically, we used factor models to estimate F_ST, and we compared our neutrality tests with those derived from a principal component analysis approach. The performances of the tests were illustrated using simulated data and by re‐analysing genomic data from European lines of the plant species Arabidopsis thaliana and human genomic data from the population reference sample, POPRES.     

Changes in P3b Latency and Amplitude Reflect Expertise Acquisition in a Football Visuomotor Learning Task

Learning is not a unitary phenomenon. Rather, learning progresses through stages, with the stages reflecting different challenges that require the support of specific cognitive processes that reflect the functions of different brain networks. A theory of general learning proposes that learning can be divided into early and late stages controlled by corticolimbic networks located in frontal and posterior brain regions, respectively. Recent human studies using dense-array EEG (dEEG) support these results by showing progressive increases in P3b amplitude (an Event Related Potential with estimated sources in posterior cingulate cortex and hippocampus) as participants acquire a new visuomotor skill. In the present study, the P3b was used to track the learning and performance of participants as they identify defensive football formations and make an appropriate response. Participants acquired the task over three days, and P3b latency and amplitude significantly changed when participants learned the task. As participants demonstrated further proficiency with extensive training, amplitude and latency changes in the P3b continued to closely mirror performance improvements. Source localization results across all days suggest that an important source generator of the P3b is located in the posterior cingulate cortex. Results from the study support prior findings and further suggest that the careful analysis of covert learning mechanisms and their underlying electrical signatures are a robust index of task competency.     

Cytotoxic components of Zingiber zerumbet,Curcuma zedoaria and C. domestica

One new and five known compounds, which all showed cytotoxic activity, were isolated from the rhizomes of Zingiber zerumbet. The new compound was 3″,4″-O-diacetylafzelin. The known compounds were zerumbone, zerumbone epoxide, diferuloylmethane, feruloyl-p-coumaroylmethane and di-p-coumaroylmethane. Several substituted cinnamoylmethanes were synthesized and tested for cytotoxic properties. Among these were tricinnamoylmethane and triferuloylmethane. The structures were elucidated mainly by spectroscopic methods and ¹³C NMR data are given.     

Conversion of soybean sterols into 3,17-diketosteroids using actinobacteria <Emphasis Type=Italic>Mycobacterium neoaurum,Pimelobacter simplex</Emphasis>, and <Emphasis Type=Italic>Rhodococcus erythropolis</Emphasis>

Soybean sterols were converted into androst-4-ene-3,17-dione (AD) and 9α-hydroxyandrost-4-ene-3,17-dione (9-OH-AD) using three actinobacterium strains. The transformation of a microcrystallic substrate (particle size 5–15 μm) or the transformation in the presence of randomly methylated β-cyclodextrin (MCD) were carried out by Mycobacterium neoaurum with a phytosterol load of 30 g/l over 144 h with an AD content of 14.5 and 15.2 g/l, respectively. AD obtained in the presence of MCD was transformed into ADD (13.5 g/l) by Pimelobacter simplex cells over 3 h and into 9-OH-AD by Rhodococcus erythropolis cells after 22 h without the isolation of AD from the cultural liquid. The crude product ADD was obtained in 75% yield, based on phytosterol. It contained as by-products 1.25% of AD and 1.5% of 1,2-dehydrotestosterone. In a control experiment—the process of 1,2-dehydrogenation of 20 g/l AD in the water solution of MCD—no by-products were isolated. Thus, it is more expedient to introduce the 1,2-double bond into pure AD, whereas R. erythropolis strain with low destructive activity towards steroid nucleus can be used in the mixed culture with M. neoaurum. The crystal product contained, according to HPLC, 80% of 9-OH-AD, and 1.5% AD was obtained. The yield of 9-OH-AD (m.p. 218–220°C) based on transformed phytosterol was 56%.     

Chlorinated and brominated polycyclic aromatic hydrocarbons in ambient air: seasonal variation,profiles, potential sources,and size distribution

Reviews in Environmental Science and Bio/Technology - Chlorinated and brominated polycyclic aromatic hydrocarbons (ClPAHs and BrPAHs, respectively) are a new derivative group of PAHs. These...     

Low-Level Vibrations Retain Bone Marrow's Osteogenic Potential and Augment Recovery of Trabecular Bone during Reambulation

Mechanical disuse will bias bone marrow stromal cells towards adipogenesis, ultimately compromising the regenerative capacity of the stem cell pool and impeding the rapid and full recovery of bone morphology. Here, it was tested whether brief daily exposure to high-frequency, low-magnitude vibrations can preserve the marrow environment during disuse and enhance the initiation of tissue recovery upon reambulation. Male C57BL/6J mice were subjected to hindlimb unloading (HU, n = 24), HU interrupted by weight-bearing for 15 min/d (HU+SHAM, n = 24), HU interrupted by low-level whole body vibrations (0.2 g, 90 Hz) for 15 min/d (HU+VIB, n = 24), or served as age-matched controls (AC, n = 24). Following 3 w of disuse, half of the mice in each group were released for 3 w of reambulation (RA), while the others were sacrificed. RA+VIB mice continued to receive vibrations for 15 min/d while RA+SHAM continued to receive sham loading. After disuse, HU+VIB mice had a 30% greater osteogenic marrow stromal cell population, 30% smaller osteoclast surface, 76% greater osteoblast surface but similar trabecular bone volume fraction compared to HU. After 3 w of reambulation, trabecular bone of RA+VIB mice had a 30% greater bone volume fraction, 51% greater marrow osteoprogenitor population, 83% greater osteoblast surfaces, 59% greater bone formation rates, and a 235% greater ratio of bone lining osteoblasts to marrow adipocytes than RA mice. A subsequent experiment indicated that receiving the mechanical intervention only during disuse, rather than only during reambulation, was more effective in altering trabecular morphology. These data indicate that the osteogenic potential of bone marrow cells is retained by low-magnitude vibrations during disuse, an attribute which may have contributed to an enhanced recovery of bone morphology during reambulation.     

Adenovirus-Mediated Efficient Gene Transfer into Cultured Three-Dimensional Organoids

Three-dimensional organoids have been recently established from various tissue-specific progenitors (such as intestinal stem cells), induced pluripotent stem cells, or embryonic stem cells. These cultured self-sustaining stem cell–based organoids may become valuable systems to study the roles of tissue-specific stem cells in tissue genesis and disease development. It is thus conceivable that effective genetic manipulations in such organoids may allow us to reconstruct disease processes and/or develop novel therapeutics. Recombinant adenoviruses are one of the most commonly used viral vectors for in vitro and in vivo gene deliveries. In this study, we investigate if adenoviruses can be used to effectively deliver transgenes into the cultured “mini-gut” organoids derived from intestinal stem cells. Using adenoviral vectors that express fluorescent proteins, we demonstrate that adenoviruses can effectively deliver transgenes into the cultured 3-D “mini-gut” organoids. The transgene expression can last at least 10 days in the cultured organoids. As a proof-of-principle experiment, we demonstrate that adenovirus-mediated noggin expression effectively support the survival and self-renewal of mini-gut organoids, while adenovirus-mediated expression of BMP4 inhibits the self-sustainability and proliferation of the organoids. Thus, our results strongly suggest that adenovirus vectors can be explored as effective gene delivery vehicles to introduce genetic manipulations in 3-D organoids.