Xp-duplications with and without sex reversal

Duplications in Xp including the DSS (dosage sensitive sex reversal) region cause male to female sex reversal. We investigated two patients from families with Xp duplications. The first case was one of two sisters with karyotype 46,XY, der(22), t(X;22)(p11.3;p11)mat and unambiguous female genitalia. The living sister was developmentally retarded, and showed multiple dysmorphic features and an acrocallosal syndrome. The second case was a boy with a maternally inherited direct duplication of Xp21.3-pter with the breakpoint close to the DSS locus. He had multiple abnormalities and micropenis, but otherwise unambiguous male genitalia. We performed quantitative Southern blot analysis with probes from Xp22.13 to p21.2 to define the duplicated region. Clinical, cytogenetic, and molecular data from both patients were compared with those of previously reported related cases. A comparison of the extragenital symptoms revealed no differences between patients with or without sex reversal. In both cases, the symptoms were non-specific. Among 22 patients with a duplication in Xp, nine had unambiguous female genitalia and a well-documented duplication of the DSS region. Two patients with duplication of DSS showed ambiguous external genitalia. From these data, we conclude that induction of testicular tissue may start in these patients, but that the type of genitalia depends on the degree of subsequent degeneration by a gene in DSS.     

Cryptic coloration and choice of escape microhabitats by grasshoppers (Orthoptera: Acrididae)

Cryptic coloration is found in many Orthoptera, especially in Acrididae, showing a great variety of forms. In a grasshopper assemblage in southeastern Brazil, preferences for escape places were detected; grasshoppers tended to escape to backgrounds in which they seem to be more cryptic. Coloration was measured using the Simpson diversity index, to quantify 'aspect diversity' (diversity of colours and shapes of patches along the insect's body). A weak positive correlation was found between grasshoppers' aspect diversity and diversification in use of escape places (use of many backgrounds to escape). Grasshoppers with similar colour patterns tended to use the same structures (leaves, sandy soil, stones) to escape.     

Delta 9-tetrahydrocannabinol decreases cytotoxic T lymphocyte activity to herpes simplex virus type 1-infected cells.

The purpose of this study was to examine the effect of delta 9-tetrahydrocannabinol (delta 9-THC), the major psychoactive component of marijuana, on T lymphocyte functional competence against herpes simplex virus Type 1 (HSV1) infection. Spleen cells from C3H/HeJ (H-2k) mice primed with HSV1 and exposed to delta 9-THC were examined for anti-HSV1 cytolytic T lymphocyte (CTL) activity. Flow cytometry was used to determine whether delta 9-THC altered T cytotoxic (Lyt-2+) and T helper (L3T4+) lymphocyte numbers or cell ratios. Nomarski optics microscopy was used to determine whether effector lymphocytes from drug-treated mice were able to bind to virally infected L929 (H-2k) target cells. Cytotoxicity assays demonstrated that CTL from mice exposed to delta 9-THC were deficient in anti-HSV1 cytolytic activity. delta 9-THC in vivo treatment had little effect on the number of T lymphocytes expressing the Lyt-2 or L3T4 antigens. Nomarski optics microscopy revealed that the CTL from the drug-treated mice were able to bind specifically to the HSV1-infected targets. However, delta 9-THC in vivo exposure affected CTL cytoplasmic polarization toward the virus-infected target cell. CTL granule reorientation toward the effector cell-target cell interface following cell conjugation occurred at a lower frequency in co-cultures containing CTL from drug-treated mice. These results suggest that delta 9-THC elicits dysfunction in CTL by altering effector cell-target cell postconjugation events.     

Insulin/IGF-I Signaling Pathways Enhances Tumor Cell Invasion through Bisecting GlcNAc N-glycans Modulation. An Interplay with E-Cadherin

Changes in glycosylation are considered a hallmark of cancer, and one of the key targets of glycosylation modifications is E-cadherin. We and others have previously demonstrated that E-cadherin has a role in the regulation of bisecting GlcNAc N-glycans expression, remaining to be determined the E-cadherin-dependent signaling pathway involved in this N-glycans expression regulation. In this study, we analysed the impact of E-cadherin expression in the activation profile of receptor tyrosine kinases such as insulin receptor (IR) and IGF-I receptor (IGF-IR). We demonstrated that exogenous E-cadherin expression inhibits IR, IGF-IR and ERK 1/2 phosphorylation. Stimulation with insulin and IGF-I in MDA-MD-435 cancer cells overexpressing E-cadherin induces a decrease of bisecting GlcNAc N-glycans that was accompanied with alterations on E-cadherin cellular localization. Concomitantly, IR/IGF-IR signaling activation induced a mesenchymal-like phenotype of cancer cells together with an increased tumor cell invasion capability. Altogether, these results demonstrate an interplay between E-cadherin and IR/IGF-IR signaling as major networking players in the regulation of bisecting N-glycans expression, with important effects in the modulation of epithelial characteristics and tumor cell invasion. Here we provide new insights into the role that Insulin/IGF-I signaling play during cancer progression through glycosylation modifications.     

Cylindrocarpon root rot: multi-gene analysis reveals novel species within the Ilyonectria radicicola species complex

Ilyonectria radicicola and its Cylindrocarpon-like anamorph represent a species complex that is commonly associated with root rot disease symptoms on a range of hosts. During the course of this study, several species could be distinguished from I. radicicola sensu stricto based on morphological and culture characteristics. DNA sequence analysis of the partial ??-tubulin, histone H3, translation elongation factor 1-?? and nuclear ribosomal RNA-Internal Transcribed Spacer (nrRNA-ITS) genes were employed to provide further support for the morphological species resolved among 68 isolates associated with root rot disease symptoms. Of the various loci screened, nrRNA-ITS sequences were the least informative, while histone H3 sequences were the most informative, resolving the same number of species as the combined dataset across the four genes. Within the Ilyonectria radicicola species complex, 12 new taxa are delineated occurring on a diverse range of hosts, the most common being Cyclamen, Lilium, Panax, Pseudotsuga, Quercus and Vitis.     

Potential mineralization of nitrogen from organic wastes to ryegrass and wheat crops

Two-pot experiments with ryegrass and wheat plants were conducted in a Cambic Arenosol to test the reliability of N fate predicted by incubation experiments previously performed, with the same soil, to assess potentially mineralizable nitrogen from six organic wastes (municipal solid waste compost, secondary pulp mill sludge, horn meal, poultry manure, solid phase from pig slurry and composted pig manure). Two treatments, corresponding to 80 and 160 kgN/ha were tested, with or without mineral N fertilization. Experimental data obtained in the pot trials was consistent with nitrogen net mineralization trend observed in the aerobic incubations with all the wastes tested. Values of potentially mineralizable nitrogen (N(0)) from the equations obtained by model fitting, to the incubation data, were well correlated to ryegrass and wheat N uptake. Poultry manure was the most efficient N supplier to crops.     

A difference between two strains of rats in their liver non-haem iron content and in their response to the porphyrogenic effect of hexachlorobenzene.

Female Agus rats developed hepatic porphyria at a much faster rate than female Porton-Wistar rats when fed a diet containing 0.01% of hexachlorobenzene (HCB). They also showed a greater inhibition of liver uroporphyrinogen decarboxylase [EC 4.1.1.37] activity and a marked stimulation of 5-aminolaevulinate synthetase [EC 2.3.1.37]. The difference between the two strains could not be correlated with differences in the liver concentrations of HCB. However, control Agus rats were found to possess significantly higher levels of total non-haem iron in their livers than the Porton animals. This was particularly apparent after 24 h of starvation and is further evidence for the involvement of iron in the pathogenesis of HCB-induced porphyria. The posterior lobes of the livers from the Agus rats given HCB became porphyric more slowly than the remainder with less severe inhibition of uroporphyrinogen decarboxylase. In contrast to their increased susceptibility to HCB, the Agus rats were less susceptible to another prophyrogenic agent, 3,5-diethoxycarbonyl-1,4-dihydrocollidine.     

Understanding extinction debts: spatio–temporal scales,mechanisms and a roadmap for future research

Extinction debt refers to delayed species extinctions expected as a consequence of ecosystem perturbation. Quantifying such extinctions and investigating long‐term consequences of perturbations has proven challenging, because perturbations are not isolated and occur across various spatial and temporal scales, from local habitat losses to global warming. Additionally, the relative importance of eco‐evolutionary processes varies across scales, because levels of ecological organization, i.e. individuals, (meta)populations and (meta)communities, respond hierarchically to perturbations. To summarize our current knowledge of the scales and mechanisms influencing extinction debts, we reviewed recent empirical, theoretical and methodological studies addressing either the spatio–temporal scales of extinction debts or the eco‐evolutionary mechanisms delaying extinctions. Extinction debts were detected across a range of ecosystems and taxonomic groups, with estimates ranging from 9 to 90% of current species richness. The duration over which debts have been sustained varies from 5 to 570 yr, and projections of the total period required to settle a debt can extend to 1000 yr. Reported causes of delayed extinctions are 1) life‐history traits that prolong individual survival, and 2) population and metapopulation dynamics that maintain populations under deteriorated conditions. Other potential factors that may extend survival time such as microevolutionary dynamics, or delayed extinctions of interaction partners, have rarely been analyzed. Therefore, we propose a roadmap for future research with three key avenues: 1) the microevolutionary dynamics of extinction processes, 2) the disjunctive loss of interacting species and 3) the impact of multiple regimes of perturbation on the payment of debts. For their ability to integrate processes occurring at different levels of ecological organization, we highlight mechanistic simulation models as tools to address these knowledge gaps and to deepen our understanding of extinction dynamics.     

Investigation of the operational stabilities and kinetics of glucoamylase immobilized on alkylamine derivatives of titanium(IV)-activated porous inorganic supports

Glucoamylase (exo-1,4-α-d-glucosidase, EC 3.2.3.1) was coupled to several porous silica matrices by an improved metal-link/chelation process using alkylamine derivatives of titanium(IV)-activated supports. In order to select the titanium activation procedure which gave stable enzyme preparations, long-term stability tests were performed. The immobilized glucoamylase preparations, in which the carrier was activated to dryness with a 15% w/v TiCl₄ solution, displayed very stable behaviour, with half-lives of ～60 days. The optimum operating conditions were determined for these preparations. There are significant differences between the behaviour of the immobilized enzyme and the free enzyme. The apparent K_m increased on immobilization due to diffusional resistances. The pH optimum for the immobilized preparation showed a slight shift to acid pH relative to that of the soluble enzyme. Also, the optimum temperature descreased to 60°C after immobilization. In order to test Michaelis-Menten kinetics at high degrees of conversion, time-course analysis of soluble starch hydrolysis was performed. It was observed that simple Michaelis-Menten kinetics are not applicable to the free/immobilized glucoamylase-starch system at high degrees of conversion.     

Application of empirical design methodologies to the study of the influence of reaction conditions and N-alpha-protecting group structure on the enzymatic X-Phe-Leu-NH(2) dipeptide synthesis in buffer/dimethylformamide solvents systems

The influence of five different N-terminal protecting groups (For, Ac, Boc, Z, and Fmoc) and reaction conditions (temperature and dimethylformamide content) on the alpha-chymotrypsin-catalyzed synthesis of the dipeptide derivative X-Phe-Leu-NH(2) was studied. Groups such as For, Ac, Boc, and Z always rendered good peptide yields (82% to 85%) at low reaction temperatures and DMF concentrations, which depended on the N-alpha protection choice. Boc and Z were the most reactive N-alpha groups and, in addition, the most suitable for peptide synthesis. On the other hand, the use of empirical design methodologies allowed, with minimal experimentation and by multiple regression, to deduce an equation, which correlates the logarithm of the first order kinetic constant (log k') with reaction temperature, DMF concentration, and hydrophobicity (log P values) of the different protecting groups. The predictive value of the equation was tested by comparing the performance of another protective group, such as Aloc, with the performance predicted by said equation. Experimental and calculated k' values were found to be in good agreement.