Some Filamentous Fungi on Grassland Vegetation from Kenya

Herbaceous plants endemic to native Kenyan grassland on the Marula Estate were assessed for their phylloplane fungal occurrence using leaf cultures on tap water agar. From 26 sampled plants, 261 fungal isolates representative of 58 genera and 92 taxa were identified. The principal filamentous fungi were of the genera: Alternaria, Bipolaris, Curvularia, Epicoccum, Fusarium, Nigrospora, Periconia, Phoma and Pithomyces. The fungal species that occurred most frequently were: Alternaria alternata aggreate (73%), Pithomyces chartarum (73%) Nigrospora sphaerica (42%), Torula herbarum (30%) and Microsphaeropsis olivacea (27%). Fungi of limited occurrence were: Didymosphaeria oblitescens, Doliomyces mysoriensis, Endophragmiella dimorphospora, Parapericonia angusii, Podospora minicaudata, Spegazzinia tessarthra, Sporormiella minima, Stagonospora vitensis, Stigmella effigurata and Truncatella conorum-piceae. It is postulated that the phylloplane of these endemic plants provides a niche for endemic fungi. This revised version was published online in June 2006 with corrections to the Cover Date.     

Characteristics of cryptic/ectopic and contralateral scrotal testes in dogs between 1 and 2 years of age

Testicular malposition represents a common developmental genital defect in dogs and can affect one or both testes. In both humans and dogs, unilateral cryptorchism is more frequently detected and thought to be the expression of a genetic abnormality affecting both the undescended and scrotal testis. In the dog, there is evidence of degenerative processes affecting the maldescended testis. However, the histologic and functional changes that occur in the scrotal testis of unilateral cryptorchid or ectopic individuals remain a source of debate. Because the bilateral surgical removal of the testes leads to some undesirable side effects, the aim of this study was to evaluate the necessity for performing bilateral orchiectomy in young unilateral cryptorchid dogs. A morphologic study of both cryptic/ectopic and scrotal testes in young dogs affected by unilateral testicular maldescent was therefore conducted. The study was conducted on 10 dogs aged 1 to 2 yr and affected by unilateral testicular maldescent. We found that, in young dogs, even if no neoplastic lesions were observed, morphologic abnormalities are detectable between 1 and 2 yr of age in the maldescended testes with severity dependent on testicular position. In contrast, in the scrotal testes, the histologic and immunohistochemical exam failed to find signs of incorrect development or morphologic abnormalities. The results seem to suggest that, though the early removal of the undescended testis is recommended, continuous monitoring of the scrotal testis for the life of the dog is preferable to removing it considering the undesirable side effects related to castration.     

Pre-adipocytes commitment to neurogenesis 1: Preliminary localisation of cholinergic molecules

A great effort has recently been made to obtain human stem cells able to differentiate into cholinergic neurons, as a number of diseases are associated to the cholinergic neuron loss, degeneration or incorrect function (Alzheimer's disease and motor neuron disease). A stem cell population (i.e. pre-adipocytes) is present in the adipose stromal compartment. Pre-adipocytes, like the mesodermic derivative cells, retain high plasticity and potentiality to convert in vitro from one phenotype into many others, and they can be isolated from adult adipose tissue. Pre-adipocytes committed in vitro to neural differentiation were followed up to the acquisition of neural morphology. Acetylcholinesterase and choline acetyltransferase are expressed from the native cell stage, with different localisations and roles during neural commitment. Western blots show the beginning of a new synthesis of these enzymes at 4 weeks of culture of neurogenic pre-adipocytes, in parallel with neural morphology. The passage of the choline-acetyltransferase immunoreactivity from cytoplasmic to membrane localisation shows the possible onset of catalytic activity and the histochemical reaction confirms the activity of acetylcholinesterase. This explains the possibility of obtaining cholinergic-like phenotype from pre-adipocytes.     

Effect of the replacement of tropical forests with tree plantations on soil organic carbon levels in the Jomoro district,Ghana

Background and aims

In the Jomoro district in Ghana, tree plantations were the first cause of deforestation in the past, drastically reducing the area occupied by primary forests. The aim of this study was to quantify soil organic carbon (SOC) losses due to a change in land use from primary forest to tree plantations (cocoa, coconut, rubber, oil palm) on the different substrates of the district. Secondary forests and mixed plantations were also included in the study.

Methods

Soils were sampled at different depths up to 100 cm along a series of chronosequences in each of the three substrates (Granite, Lower Birrimian and Tertiary Sands) present in the area.

Results

The highest SOC losses in the 0–30 cm layer were caused by the conversion of primary forests to tree plantations: cocoa ?61 % of the original SOC stock, coconut ?55 %, rubber ?35 % and oil palm 28 %, while mixed plantations and secondary forests showed a loss of 23 % and 21 % of the original SOC stock, respectively. C losses were less apparent from the entire profile (to a depth of 100 cm).

Conclusions

All conversions to tree plantations caused substantial SOC losses, comparable to the conversion of forests to agricultural systems. Secondary forests and mixed plantations were the only sustainable land uses that restricted SOC losses considerably.     

ATM activates the pentose phosphate pathway promoting anti-oxidant defence and DNA repair

Ataxia telangiectasia (A-T) is a human disease caused by ATM deficiency characterized among other symptoms by radiosensitivity, cancer, sterility, immunodeficiency and neurological defects. ATM controls several aspects of cell cycle and promotes repair of double strand breaks (DSBs). This probably accounts for most of A-T clinical manifestations. However, an impaired response to reactive oxygen species (ROS) might also contribute to A-T pathogenesis. Here, we show that ATM promotes an anti-oxidant response by regulating the pentose phosphate pathway (PPP). ATM activation induces glucose-6-phosphate dehydrogenase (G6PD) activity, the limiting enzyme of the PPP responsible for the production of NADPH, an essential anti-oxidant cofactor. ATM promotes Hsp27 phosphorylation and binding to G6PD, stimulating its activity. We also show that ATM-dependent PPP stimulation increases nucleotide production and that G6PD-deficient cells are impaired for DSB repair. These data suggest that ATM protects cells from ROS accumulation by stimulating NADPH production and promoting the synthesis of nucleotides required for the repair of DSBs.     

Expression of Lactobacillus brevis IOEB 9809 tyrosine decarboxylase and agmatine deiminase genes in wine correlates with substrate availability

Aims: Lactobacillus brevis IOEB 9809 is able to produce both tyramine and putrescine via tyrosine decarboxylase and agmatine deiminase enzymes, respectively, when cultured on synthetic media. The aims of this study were to assess the expression of L. brevis IOEB 9809 tdc and aguA1 genes, during wine fermentation and to evaluate the effect of substrate availability and pH on tdc and aguA1 expression, as well as on biogenic amine production and L. brevis viability. Methods and Results: The relative expression of L. brevis IOEB 9809 tdc and aguA1 genes was analysed in wine by quantitative real‐time RT‐PCR (qRT‐PCR) during a period of incubation of 30 days. Cell viability, pH values, putrescine and tyramine concentration were monitored throughout the experiments. Conclusions: The wine trials indicated that L. brevis IOEB 9809 is able to produce both tyramine and putrescine during wine fermentation. Increased cell viability was also observed in wine supplemented with tyrosine or agmatine. qRT‐PCR analysis suggests a strong influence of substrate availability on the expression of genes coding for tyrosine decarboxylase and agmatine deiminase in L. brevis IOEB 9809. Less evident is the relationship between putrescine and tyramine production and tolerance to wine pH. Significance and Impact of Study: To our knowledge, this study represents the first assessment of relative expression of L. brevis IOEB 9809 genes involved in biogenic amine production in wine. Furthermore, an effect of biogenic amine production on viability of L. brevis during wine fermentation was established.     

Urotensin II receptor predicts the clinical outcome of prostate cancer patients and is involved in the regulation of motility of prostate adenocarcinoma cells

Urotensin II (UT-II) is a potent vasoconstrictor peptide and its receptor (UTR) was correlated with human cortico-adrenal carcinoma proliferation. In this study, we have evaluated the correlation between UTR expression and prognosis of human prostate adenocarcinoma and the involvement of this receptor in the regulation of biological properties on both in vivo and in vitro models. UTR mRNA and protein, evaluated by real-time PCR and Western blotting, respectively, were expressed at high levels only in androgen-dependent LNCaP cells. In order to investigate UTR changes occurring in human prostate tumorigenesis, we have also evaluated the expression of UTR in vivo in 195 human prostate tissue samples. UTR was always expressed at low intensity in hyperplastic tissues and at high intensity in well-differentiated carcinomas (Gleason 2-3). Moreover, we have evaluated the effects of an antagonist of UTR, urantide on migration and invasion of LNCaP cells. Urantide induced a dose-dependent decrease of motility and invasion of LNCaP cells whose characteristic ameboid movement seems to be advantageous for their malignancy. These effects were paralleled by down-regulating the autophosphorylation of focal adhesion kinase and the integrin surface expression on LNCaP cells. The effects on cell motility and invasion were likely due to the inhibition of RhoA activity induced by both urantide and shRNA UTR. These data suggest that UTR can be considered a prognostic marker in human prostate adenocarcinoma patients.