Chlorella vulgaris (Chlorellaceae) does not secrete autoinhibitors at high cell densities

Filtrates (conditioned medium) from high-density Chlorella vulgaris cultures in photobioreactors were obtained and tested for autoinhibitory activity under different conditions. Exponentially growing cells were inoculated at low initial cell concentration (2 × 10⁵ cells/ml) in 90% conditioned medium (CM) supplemented with 10% fresh medium (FM) at low (atmospheric) CO₂ levels. The time sequence of DNA histograms of cells in CM cultures showed that there is an accumulation of cells with two and four DNA equivalents in the culture over a period of time, signifying a blockage of cells at the division stage of the cell cycle. Examination of the chemical composition of CM showed the presence of high concentrations (> 10 mM) of bicarbonate. Adding similar bicarbonate concentrations to FM were found to have similar effects as CM cultures, causing blockage of cell division, though the intensity of the blocking effect was lower. The bicarbonate-free CM did not show any cell cycle modulating or inhibitory activity. The growth of cells cultivated at high (5%) CO₂ levels in 90% CM supplemented with 10% FM was comparable to 10% FM cultures, indicating nutrient limitation in 90% CM culture. When the 90% CM culture was supplemented with 100% nutrients, the growth rate and final cell concentration was similar to 100% FM culture. Based on these results we conclude that C. vulgaris does not secrete any autoinhibitor(s) or cell cycle modulating compound(s) under the conditions from which the CM was obtained.     

Synthetic analogues of the montanine-type alkaloids with activity against apoptosis-resistant cancer cells

In a search of small molecules active against apoptosis-resistant cancer cells, a skeletal rearrangement of alkaloid haemanthamine was utilized to generate a series of compounds possessing the alkaloid montanine ring system. The synthesized compounds were found to inhibit proliferation of cancer cells resistant to apoptosis at micromolar concentrations. Selected compounds were also active against patient-derived glioblastoma cells expressing stem-cell markers. This is the first report describing the preparation of synthetic analogues of the montanine-type alkaloids with antiproliferative activity. The compounds prepared in the current investigation appear to be a useful starting point for the development of agents to fight cancers with apoptosis resistance, and thus, associated with poor prognoses.     

Differential proteomic profiling identifies novel molecular targets of pterostilbene against experimental diabetes

Pterostilbene (PTS), a naturally occurring stilbene, confers protection against oxidative and cytokine stress induced pancreatic β-cell apoptosis in vitro and in vivo. To provide insights into the molecular mechanism, we performed a proteomic study on the pancreas of PTS-treated diabetic mice using electrospray ionization tandem–mass spectrometry (LC–MS/MS). A total of 1,260 proteins were detected in triplicate samples. Of which, 359 proteins were found to be differentially regulated in streptozotocin-induced diabetic mice pancreas with two fold difference ( P < 0.05, two or more peptides) and on PTS treatment 315 proteins were normalized to control levels. Gene ontology (GO) indicated that majority of the differentially regulated proteins are involved in cellular functions such as metabolism, cellular structure, oxidative stress, endoplasmic-reticulum-associated protein degradation (ERAD) pathway and several stress sensors. Protein–protein interaction network analysis of these differentially expressed proteins showed clustering of proteins involved in protein processing in endoplasmic reticulum (protein synthesis machinery and protein folding), oxidative phosphorylation/oxidative stress proteins, oligosaccharide metabolic process, and antioxidant activity. Our results highlighted that PTS administration rehabilitated the defective metabolic process and redox imbalance, and also suppressed the unfolded protein response and ERAD pathways. The effects on targeting ER machinery and suppressing oxidative stress suggest the great potential of PTS for diabetes management.     

A spatially explicit data-driven approach to assess the effect of agricultural land occupation on species groups

Purpose

Change of vegetation cover and increased land use intensity, particularly for agricultural use, can affect species richness. Within life cycle impact assessment, methods to assess impacts of land use on a global scale are still in need of development. In this work, we present a spatially explicit data-driven approach to characterize the effect of agricultural land occupation on different species groups.

Methods

We derived characterization factors for the direct impact of agricultural land occupation on relative species richness. Our method identifies potential differences in impacts for cultivation of different crop types, on different species groups, and in different world regions. Using empirical species richness data gathered via an extensive literature search, characterization factors were calculated for four crop groups (oil palm, low crops, Pooideae, and Panicoideae), four species groups (arthropods, birds, mammals, and vascular plants), and six biomes.

Results and discussion

Analysis of the collected data showed that vascular plant richness is more sensitive than the species richness of arthropods to agricultural land occupation. Regarding the differences between world regions, the impact of agricultural land use was lower in boreal forests/taiga than in temperate and tropical regions. The impact of oil palm plantations was found to be larger than that of Pooideae croplands, although we cannot rule out that this difference is influenced by the spatial difference between the oil palm- and Pooideae-growing regions as well. Analysis of a subset of data showed that the impact of conventional farming was larger than the impact of low-input farming.

Conclusions

The impact of land occupation on relative species richness depends on the taxonomic groups considered, the climatic region, and farm management. The influence of crop type, however, was found to be of less importance.     

Unexpected formation of 3-chloro-1-hydroxy-2,6-diarylpiperidin-4-ones: synthesis, antibacterial and antifungal activities

New 3-chloro-1-hydroxy-2,6-diarylpiperidin-4-ones 18-22 were synthesized, characterized by melting point, elemental analysis, MS, FT-IR, one-dimensional NMR ((1)H & (13)C) spectroscopic data and evaluated for their in vitro antibacterial and antifungal activities. All the newly synthesized compounds exerted a wide range of antibacterial activities against the entire tested gram-positive and gram-negative bacterial strains except Escherichia coli. Compounds 21 and 22 exerted strong antifungal activities against Aspergillus flavus, mucor and Microsporum gypsuem. In addition, compound 20 was more potent against Rhizopus.     

Interleukin-8: novel roles in human airway smooth muscle cell contraction and migration

In patients with cystic fibrosis (CF) and asthma, elevated levels of interleukin-8 (IL-8) are found in the airways. IL-8 is a CXC chemokine that is a chemoattractant for neutrophils through CXCR1 and CXCR2 G protein-coupled receptors. We hypothesized that IL-8 acts directly on airway smooth muscle cells (ASMC) in a way that may contribute to the enhanced airway responsiveness and airway remodeling observed in CF and asthma. The aim of this study was to determine whether human ASMC (HASMC) express functional IL-8 receptors (CXCR1 and CXCR2) linked to cell contraction and migration. Experiments were conducted on cells harvested from human lung specimens. Real-time PCR and fluorescence-activated cell sorting analysis showed that HASMC expressed mRNA and protein for both CXCR1 and CXCR2. Intracellular Ca²⁺ concentration ([Ca²⁺]_i) increased from 115 to 170 nM in response to IL-8 (100 nM) and decreased after inhibition of phospholipase C (PLC) with U-73122. On blocking the receptors with specific neutralizing antibodies, changes in [Ca²⁺]_i were abrogated. IL-8 also contracted the HASMC, decreasing the length of cells by 15%, and induced a 2.5-fold increase in migration. These results indicate that HASMC constitutively express functional CXCR1 and CXCR2 that mediate IL-8-triggered Ca²⁺ release, contraction, and migration. These data suggest a potential role for IL-8 in causing abnormal airway structure and function in asthma and CF. chemokines; lung; signal transduction     

Curative effect of Semecarpus anacardium Linn. nut milk extract against adjuvant arthritis -- with special reference to bone metabolism

Localised bone loss in the form of bone erosions and peri-articular osteopenia constitutes an important criteria for the diagnosis of rheumatoid arthritis. In the present study, the effect of Semecarpus anacardium Linn. nut milk extract (SA) on the metabolism of bone turn over has been studied by analyzing various markers of bone turnover and by histological and radiological analysis of the joints in adjuvant arthritis in rats. Arthritis was induced in rats by injecting Freund's complete adjuvant containing 10mg of heat killed mycobacterium tuberculosis in 1 ml paraffin oil (0.1 ml) into the left hind paw of the rat intradermally. After 14 days of induction, SA (150 mg/kg body weight/day) was administered orally by gastric intubations for 14 days. SA significantly reverted the alterations in the bone turnover observed in arthritic animals by modulating the levels of calcium, phosphorus and the activities of the enzymes names tartrate resistant acid phosphatase, acid phosphatase and alkaline phosphatase. The drug increased the bone weights that were found to be decreased during arthritis. Protective effect of SA was also observed by the decrease in the levels and expression of tumour necrosis factor alpha (TNF-alpha) as well as the histopathological and radiological observations. From all these observations it can be concluded that SA possesses strong anti-arthritic property by regulating bone turnover.     

Pin1 Promotes Transforming Growth Factor-��-induced Migration and Invasion

Transforming growth factor-β (TGF-β) regulates a wide variety of biological activities. It induces potent growth-inhibitory responses in normal cells but promotes migration and invasion of cancer cells. Smads mediate the TGF-β responses. TGF-β binding to the cell surface receptors leads to the phosphorylation of Smad2/3 in their C terminus as well as in the proline-rich linker region. The serine/threonine phosphorylation sites in the linker region are followed by the proline residue. Pin1, a peptidyl-prolyl cis/trans isomerase, recognizes phosphorylated serine/threonine-proline motifs. Here we show that Smad2/3 interacts with Pin1 in a TGF-β-dependent manner. We further show that the phosphorylated threonine 179-proline motif in the Smad3 linker region is the major binding site for Pin1. Although epidermal growth factor also induces phosphorylation of threonine 179 and other residues in the Smad3 linker region the same as TGF-β, Pin1 is unable to bind to the epidermal growth factor-stimulated Smad3. Further analysis suggests that phosphorylation of Smad3 in the C terminus is necessary for the interaction with Pin1. Depletion of Pin1 by small hairpin RNA does not significantly affect TGF-β-induced growth-inhibitory responses and a number of TGF-β/Smad target genes analyzed. In contrast, knockdown of Pin1 in human PC3 prostate cancer cells strongly inhibited TGF-β-mediated migration and invasion. Accordingly, TGF-β induction of N-cadherin, which plays an important role in migration and invasion, is markedly reduced when Pin1 is depleted in PC3 cells. Because Pin1 is overexpressed in many cancers, our findings highlight the importance of Pin1 in TGF-β-induced migration and invasion of cancer cells.