The floating garden agricultural system of the Inle lake (Myanmar) as an example of equilibrium between food production and biodiversity maintenance

Biodiversity and Conservation - Humans have adapted to difficult environmental conditions throughout history to carry out agricultural activities that ensured their food security, modifying the...     

Site-specific chlorophyll reference conditions for lakes in Northern and Western Europe

The Water Framework Directive (WFD) requires EU Member States to assess the “ecological status” of surface waters. As a component of ecological status, many European countries are developing a classification scheme for chlorophyll concentrations as a measure of phytoplankton biomass. The chlorophyll classification must be based on the degree of divergence of a water body from an appropriate baseline or ‘reference condition’. This article describes the development of a series of regression models for predicting reference chlorophyll concentrations on a site-specific basis. For model development, a large dataset of European lakes considered to be in reference condition, 466 lakes in total, was assembled. Data were included from 12 European countries, but lakes from Northern and Western Europe dominated and made up 92% of all reference lakes. Data have been collated on chlorophyll concentration, altitude, mean depth, alkalinity, humic type, surface area and geographical region. Regression models were developed for estimating site-specific reference chlorophyll concentrations from significant predictor ‘typology’ variables. Reference chlorophyll concentrations were found to vary along a number of environmental gradients. Concentrations increased with colour and alkalinity and decreased with lake depth and altitude. Forward selection was used to identify independent explanatory variables in regression models for predicting site-specific reference chlorophyll concentrations. Depth was selected as an explanatory variable in all models. Alkalinity was included in models for low colour and humic lakes and altitude was included in models for low colour and very humic lakes. Uncertainty in the models was quite high and arises from errors in the data used to develop the models (including natural temporal and spatial variability in data) and also from additional explanatory variables not considered in the models, particularly nutrient concentrations, retention time and grazing. Despite these uncertainties, site-specific reference conditions are still recommended in preference to type-specific reference conditions, as they use the individual characteristics of a site known to influence phytoplankton biomass, rather than adopt standards set to generally represent a large population of lakes of a particular type. For this reason, site-specific reference conditions should result in reduced error in ecological status classifications, particularly for lakes close to typology boundaries.     

Mechanism and significance of specific proteolytic cleavage of Reelin

Reelin is a secreted glycoprotein essential for normal brain development and function. In the extracellular milieu, Reelin is subject to specific cleavage at two (N-t and C-t) sites. The N-t cleavage of Reelin is implicated in psychiatric and Alzheimer’s diseases, but the molecular mechanism and physiological significance of this cleavage are not completely understood. Particularly, whether the N-t cleavage affects the signaling activity of Reelin remains controversial.Here, we show that the protease in charge of the N-t cleavage of Reelin requires the activity of certain proprotein convertase family for maturation and has strong affinity for heparin. By taking advantage of these observations, we for the first time succeeded in obtaining “Uncleaved” and “Completely Cleaved” Reelin proteins. The N-t cleavage splits Reelin into two distinct fragments and virtually abolishes its signaling activity. These findings provide an important biochemical basis for the function of Reelin proteolysis in brain development and function.     

Shank2 associates with and regulates Na+/H+ exchanger 3

Na+/H+ exchanger 3 (NHE3) plays a pivotal role in transepithelial Na+ and HCO3(-) absorption across a wide range of epithelia in the digestive and renal-genitourinary systems. Accumulating evidence suggests that PDZ-based adaptor proteins play an important role in regulating the trafficking and activity of NHE3. A search for NHE3-binding modular proteins using yeast two-hybrid assays led us to the PDZ-based adaptor Shank2. The interaction between Shank2 and NHE3 was further confirmed by immunoprecipitation and surface plasmon resonance studies. When expressed in PS120/NHE3 cells, Shank2 increased the membrane expression and basal activity of NHE3 and attenuated the cAMP-dependent inhibition of NHE3 activity. Furthermore, knock-down of native Shank2 expression in Caco-2 epithelial cells by RNA interference decreased NHE3 protein expression as well as activity but amplified the inhibitory effect of cAMP on NHE3. These results indicate that Shank2 is a novel NHE3 interacting protein that is involved in the fine regulation of transepithelial salt and water transport through affecting NHE3 expression and activity.     

Direct interaction of post-synaptic density-95/Dlg/ZO-1 domain-containing synaptic molecule Shank3 with GluR1 alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor

A class of scaffolding protein containing the post-synaptic density-95/Dlg/ZO-1 (PDZ) domain is thought to be involved in synaptic trafficking of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors during development. To clarify the molecular mechanism of AMPA receptor trafficking, we performed a yeast two-hybrid screening system using the cytoplasmic tail of the GluR1 subunit of AMPA receptor as a bait and identified a synaptic molecule, Shank3/ProSAP2, as a GluR1 subunit-interacting molecule. Shank3 is a PDZ domain-containing multidomain protein and is predominantly expressed in developing neurons. Using the glutathione S-transferase pull-down assay and immunoprecipitation technique we demonstrated that the GluR1 subunit directly binds to the PDZ domain of Shank3 via its carboxyl terminal PDZ-binding motif. We raised anti-Shank3 antibody to investigate the expression of Shank3 in cortical neurons. The pattern of Shank3 immunoreactivity was strikingly punctate, mainly observed in the spines, and closely matched the pattern of post-synaptic density-95 immunoreactivity, indicating that Shank3 is colocalized with post-synaptic density-95 in the same spines. When Shank3 and the GluR1 subunit were overexpressed in primary cortical neurons, they were also colocalized in the spines. Taken together with the biochemical interaction of Shank3 with the GluR1 subunit, these results suggest that Shank3 is an important molecule that interacts with GluR1 AMPA receptor at synaptic sites of developing neurons.     

The expression profile of de-N-acetyl polysialic acid (NeuPSA) in normal and diseased human tissue

Although sialic acids have a key role in many aspects of human biology, the expression of polysialic acid (PSA) in human tissues is thought to be relatively rare. We identified a derivative of PSA called neuraminic acid-containing PSA or NeuPSA that was highly expressed in primary human melanoma tumors and in several cancer cell lines. Moreover, anti-NeuPSA antibodies could induce apoptosis of cancer cells. However, little was known about NeuPSA expression in normal or diseased tissues. In this study we investigated the complete expression profile of NeuPSA in human tissues and a few primary tumors using the anti-NeuPSA monoclonal antibody, SEAM 3. Almost every human tissue tested spanning a representative sample of all organ types was positive for SEAM 3 binding. Specificity of SEAM 3 binding was established by inhibition with NeuPSA but not closely related meningococcal C polysaccharide and loss of SEAM 3 binding when specimens were treated with periodate at high pH, which specifically destroys NeuPSA. Only subsets of cells in each specimen stained positive, and the relative staining between tissues was variable. The distribution and amount of NeuPSA antigen in tissues was correlated with known levels of polysialyltransferase PST or STX expression. The majority of anti-NeuPSA binding occurred intracellularly in the cytoplasm of cells. Tumors generally exhibited considerably increased staining compared with corresponding normal tissues. Identifying the diverse tissue distribution and intracellular location of NeuPSA provides a foundation for investigating the functional role of NeuPSA in human health and disease.     

Dietary adaptations of temperate primates: comparisons of Japanese and Barbary macaques

Habitat, diet and leaf chemistry are compared between Japanese and Barbary macaques to reveal the similarities and differences in dietary adaptations of temperate primates living at the eastern and western extremes of the genus Macaca. Tree species diversity and proportion of fleshy-fruited species are much higher in Japan than in North Africa. Both species spend considerable annual feeding time on leaves. Japanese macaques prefer fruits and seeds over leaves, and Barbary macaques prefer seeds. These characteristics are adaptive in temperate regions where fruit availability varies considerably with season, since animals can survive during the lean period by relying on leaf and other vegetative foods. The two species are different with respect to the higher consumption of herbs by Barbary macaques, and the leaves consumed contain high condensed and hydrolysable tannin for Barbary but not for Japanese macaques. Barbary macaques supplement less diverse tree foods with herbs. Because of the low species diversity and high tannin content of the dominant tree species, Barbary macaques may have developed the capacity to cope with tannin. This supports the idea that digestion of leaves is indispensable to survive in temperate regions where fruit and seed foods are not available for a prolonged period during each year.     

Pih1d3 is required for cytoplasmic preassembly of axonemal dynein in mouse sperm

Axonemal dynein complexes are preassembled in the cytoplasm before their transport to cilia, but the mechanism of this process remains unclear. We now show that mice lacking Pih1d3, a PIH1 domain–containing protein, develop normally but manifest male sterility. Pih1d3^−/− sperm were immotile and fragile, with the axoneme of the flagellum lacking outer dynein arms (ODAs) and inner dynein arms (IDAs) and showing a disturbed 9+2 microtubule organization. Pih1d3 was expressed specifically in spermatogenic cells, with the mRNA being most abundant in pachytene spermatocytes. Pih1d3 localized to the cytoplasm of spermatogenic cells but was not detected in spermatids or mature sperm. The levels of ODA and IDA proteins were reduced in the mutant testis and sperm, and Pih1d3 was found to interact with an intermediate chain of ODA as well as with Hsp70 and Hsp90. Our results suggest that Pih1d3 contributes to cytoplasmic preassembly of dynein complexes in spermatogenic cells by stabilizing and promoting complex formation by ODA and IDA proteins.