Bird and bat predation services in tropical forests and agroforestry landscapes

Understanding distribution patterns and multitrophic interactions is critical for managing bat‐ and bird‐mediated ecosystem services such as the suppression of pest and non‐pest arthropods. Despite the ecological and economic importance of bats and birds in tropical forests, agroforestry systems, and agricultural systems mixed with natural forest, a systematic review of their impact is still missing. A growing number of bird and bat exclosure experiments has improved our knowledge allowing new conclusions regarding their roles in food webs and associated ecosystem services. Here, we review the distribution patterns of insectivorous birds and bats, their local and landscape drivers, and their effects on trophic cascades in tropical ecosystems. We report that for birds but not bats community composition and relative importance of functional groups changes conspicuously from forests to habitats including both agricultural areas and forests, here termed ‘forest‐agri’ habitats, with reduced representation of insectivores in the latter. In contrast to previous theory regarding trophic cascade strength, we find that birds and bats reduce the density and biomass of arthropods in the tropics with effect sizes similar to those in temperate and boreal communities. The relative importance of birds versus bats in regulating pest abundances varies with season, geography and management. Birds and bats may even suppress tropical arthropod outbreaks, although positive effects on plant growth are not always reported. As both bats and birds are major agents of pest suppression, a better understanding of the local and landscape factors driving the variability of their impact is needed.     

Engineering of N. benthamiana L. plants for production of N-acetylgalactosamine-glycosylated proteins - towards development of a plant-based platform for production of protein therapeutics with mucin type O-glycosylation

Background

Mucin type O-glycosylation is one of the most common types of post-translational modifications that impacts stability and biological functions of many mammalian proteins. A large family of UDP-GalNAc polypeptide:N-acetyl-α-galactosaminyltransferases (GalNAc-Ts) catalyzes the first step of mucin type O-glycosylation by transferring GalNAc to serine and/or threonine residues of acceptor polypeptides. Plants do not have the enzyme machinery to perform this process, thus restricting their use as bioreactors for production of recombinant therapeutic proteins.

Results

The present study demonstrates that an isoform of the human GalNAc-Ts family, GalNAc-T2, retains its localization and functionality upon expression in N. benthamiana L. plants. The recombinant enzyme resides in the Golgi as evidenced by the fluorescence distribution pattern of the GalNAc-T2:GFP fusion and alteration of the fluorescence signature upon treatment with Brefeldin A. A GalNAc-T2-specific acceptor peptide, the 113-136 aa fragment of chorionic gonadotropin β-subunit, is glycosylated in vitro by the plant-produced enzyme at the "native" GalNAc attachment sites, Ser-121 and Ser-127. Ectopic expression of GalNAc-T2 is sufficient to "arm" tobacco cells with the ability to perform GalNAc-glycosylation, as evidenced by the attachment of GalNAc to Thr-119 of the endogenous enzyme endochitinase. However, glycosylation of highly expressed recombinant glycoproteins, like magnICON-expressed E. coli enterotoxin B subunit: H. sapiens mucin 1 tandem repeat-derived peptide fusion protein (LTBMUC1), is limited by the low endogenous UDP-GalNAc substrate pool and the insufficient translocation of UDP-GalNAc to the Golgi lumen. Further genetic engineering of the GalNAc-T2 plants by co-expressing Y. enterocolitica UDP-GlcNAc 4-epimerase gene and C. elegans UDP-GlcNAc/UDP-GalNAc transporter gene overcomes these limitations as indicated by the expression of the model LTBMUC1 protein exclusively as a glycoform.

Conclusion

Plant bioreactors can be engineered that are capable of producing Tn antigen-containing recombinant therapeutics.     

Crystal structure of polysaccharide lyase family 20 endo-β-1,4-glucuronan lyase from the filamentous fungus Trichoderma reesei

The crystal structure of endo-β-(1→4)-glucuronan lyase from Trichoderma reesei (TrGL) has been determined at 1.8 Å resolution as the first three-dimensional structure of polysaccharide lyase (PL) family 20. TrGL has a typical β-jelly roll fold, which is similar to glycoside hydrolase family 16 and PL7 enzymes. A calcium ion is bound to the site far from the cleft and appears to contribute to the stability. There are several completely conserved residues in the cleft. Possible catalytic residues are predicted based on structural comparison with PL7 alginate lyase A1-II′.     

Fetuin-A associates with histones intracellularly and shuttles them to exosomes to promote focal adhesion assembly resulting in rapid adhesion and spreading in breast carcinoma cells

The present analyses were undertaken to define the mechanisms by which fetuin-A modulates cellular adhesion. FLAG-tagged fetuin-A was expressed in breast carcinoma and HEK-293T cells. We demonstrated by confocal microscopy that fetuin-A co-localizes with histone H2A in the cell nucleus, forms stable complexes with histones such as H2A and H3 in solution, and shuttles histones to exosomes. The rate of cellular adhesion and spreading to either fibronectin or laminin coated wells was accelerated significantly in the presence of either endogenous fetuin-A or serum derived protein. More importantly, the formation of focal adhesion complexes on surfaces coated by laminin or fibronectin was accelerated in the presence of fetuin-A or histone coated exosomes. Cellular adhesion mediated by histone coated exosomes was abrogated by heparin and heparinase III. Heparinase III cleaves heparan sulfate from cell surface heparan sulfate proteoglycans. Lastly, the uptake of histone coated exosomes and subsequent cellular adhesion, was abrogated by heparin. Taken together, the data suggest a mechanism where fetuin-A, either endogenously synthesized or supplied extracellularly can extract histones from the nucleus or elsewhere in the cytosol/membrane and load them on cellular exosomes which then mediate adhesion by interacting with cell surface heparan sulfate proteoglycans via bound histones.     

A study of the efficacy of ultrasonic waves in removing biofilms

doi:10.1111/j.1741‐2358.2009.00325.x
A study of the efficacy of ultrasonic waves in removing biofilms Objective: The removal of adherent biofilms was assessed using ultrasonic waves in a non‐contact mode. Materials and Methods: In in vitro experiments, Streptococcus mutans (S. mutans) biofilms were exposed to ultrasonic waves at various frequencies (280 kHz, 1 MHz, or 2 MHz), duty ratios (0–90%), and exposure times (1–3 minutes), and the optimal conditions for biofilm removal were identified. Furthermore, the effect of adding a contrast medium, such as micro bubbles (Sonazoid^®), was examined. The spatial distribution and architecture of S. mutans biofilms before and after ultrasonic wave exposure were examined via scanning electron microscopy. The biofilm removal effect was also examined in in vivo experiments, using a custom‐made oral cleaning device. Results: When a 280 kHz probe was used, the biofilm‐removing effect increased significantly compared to 1 and 2 MHz probes; more than 80% of the adherent biofilm was removed with a duty cycle of 50–90% and a 3 minutes exposure time. The maximum biofilm‐removing effect was observed with a duty cycle of 80%. Furthermore, the addition of micro bubbles enhanced this biofilm‐removing effect. In in vivo experiments, moderate biofilm removal was observed when a 280 kHz probe was used for 5 minutes. Conclusions: This study demonstrated that ultrasonic wave exposure in a non‐contact mode effectively removed adherent biofilms composed of S. mutans in vitro.     

Expression of connective tissue growth factor in the human liver with idiopathic portal hypertension

Idiopathic portal hypertension (IPH) is a disorder of unknown etiology, clinically associated with portal hypertension in the absence of cirrhosis. This study was designed to delineate the characteristics of IPH RNA expression in liver specimens from patients with IPH. Liver specimens from patients with IPH and patients without liver diseases underwent cDNA expression analysis and in situ hybridization studies. Connective tissue growth factor (CTGF) levels in serum were examined in 76 patients with IPH, 84 patients with hepatitis C virus infection (including those with cirrhosis), and 38 healthy volunteers. Among 588 genes sorted on macroarray, seven up-regulated genes, including CTGF, were detected. In situ hybridization studies showed that positive reactions for CTGF mRNA were most intense in the epithelial cells of proliferating bile ducts within portal tracts in patients with IPH. In the liver parenchyma, there was no appreciable staining of hepatocytes, sinusoidal endothelial cells, or hepatic stellate cells (HSCs), and there were few positive signals for CTGF mRNA in normal liver. The serum CTGF level in patients with IPH was significantly higher than the value in healthy volunteers. Six (8%) of the 76 patients with IPH had serum CTGF levels greater than 80 ng/mL, far exceeding the level of any patient with cirrhosis. In conclusion, overexpression of CTGF is one of the most important features of IPH.     

Biochemical and haematological changes in HIV subjects receiving winniecure antiretroviral drug in Nigeria

Background

Hematological and biochemical abnormalities are among the most common clinicopathological manifestations of HIV patients on ART. Consequently, the development and assessment of indigenous antiretroviral drugs with minimal abnormalities becomes a necessity. The objective of this investigation was to assess potential haematological and biochemical abnormalities that may be associated with the administration of Winniecure ART in HIV patients undergoing treatment in Nigeria. Fifty (50) confirmed HIV positive ART naïve patients aged 36 ± 10 were observed for haematological and biochemical responses for 12 weeks. Haematological responses were assessed thrice at 6 weeks interval using coulter Ac-T differential analyser and biochemical indicators (bilirubin, creatine, urea, amylase, ALT, ALP, AST, albumin) assayed spectrophotometrically.

Results

The biochemical parameters ALP (P < 0.05), ALT (P < 0.0001), AST (P < 0.001) and amylase (P < 0.05) slightly increased at the 12^th week, no significant change was observed in plasma creatinine and urea concentrations while albumin levels decreased non-significantly (P > 0.002). Haematological results showed consistent reduction of ESR, eosinophil, absolute and differential lymphocytes, granulocytes and total WBC in the test subjects throughout the assessment period. Conversely, haemoglobin, platelet and PCV increased significantly (P < 0.05). At the 12^th week thrombocytopenia (10.30%) and anaemia (76%) were reduced to 2% and 31% respectively while neutropenia (4.2 to 8%), leucopenia (26.8 to 30%) and lymphopenia (1 to 10%) increased. No cases of neutrophilia, lymphocytosis, eosinophilia and leukocytosis was observed.

Conclusion

The drug has a reduced haematological abnormalities and normal kidney function was unaffected though there were signs of possible abnormal levels of hepatic enzymes beyond 12 weeks of treatment.