CDKN3 mRNA as a Biomarker for Survival and Therapeutic Target in Cervical Cancer

The cyclin-dependent kinase inhibitor 3 (CDKN3) gene, involved in mitosis, is upregulated in cervical cancer (CC). We investigated CDKN3 mRNA as a survival biomarker and potential therapeutic target for CC. CDKN3 mRNA was measured in 134 CC and 25 controls by quantitative PCR. A 5-year survival study was conducted in 121 of these CC patients. Furthermore, CDKN3-specific siRNAs were used to investigate whether CDKN3 is involved in proliferation, migration, and invasion in CC-derived cell lines (SiHa, CaSki, HeLa). CDKN3 mRNA was on average 6.4-fold higher in tumors than in controls (p = 8 x 10⁻⁶, Mann-Whitney). A total of 68.2% of CC patients over expressing CDKN3 gene (fold change ≥ 17) died within two years of diagnosis, independent of the clinical stage and HPV type (Hazard Ratio = 5.0, 95% CI: 2.5–10, p = 3.3 x 10⁻⁶, Cox proportional-hazards regression). In contrast, only 19.2% of the patients with lower CDKN3 expression died in the same period. In vitro inactivation of CDKN3 decreased cell proliferation on average 67%, although it had no effect on cell migration and invasion. CDKN3 mRNA may be a good survival biomarker and potential therapeutic target in CC.     

Clade 8 and Clade 6 Strains of Escherichia coli O157:H7 from Cattle in Argentina have Hypervirulent-Like Phenotypes

The hemolytic uremic syndrome (HUS) whose main causative agent is enterohemorrhagic Escherichia coli (EHEC) O157:H7 is a disease that mainly affects children under 5 years of age. Argentina is the country with the highest incidence of HUS in the world. Cattle are a major reservoir and source of infection with E. coli O157:H7. To date, the epidemiological factors that contribute to its prevalence are poorly understood. Single nucleotide polymorphism (SNP) typing has helped to define nine E. coli O157:H7 clades and the clade 8 strains were associated with most of the cases of severe disease. In this study, eight randomly selected isolates of EHEC O157:H7 from cattle in Argentina were studied as well as two human isolates. Four of them were classified as clade 8 through the screening for 23 SNPs; the two human isolates grouped in this clade as well, while two strains were closely related to strains representing clade 6. To assess the pathogenicity of these strains, we assayed correlates of virulence. Shiga toxin production was determined by an ELISA kit. Four strains were high producers and one of these strains that belonged to a novel genotype showed high verocytotoxic activity in cultured cells. Also, these clade 8 and 6 strains showed high RBC lysis and adherence to epithelial cells. One of the clade 6 strains showed stronger inhibition of normal water absorption than E. coli O157:H7 EDL933 in human colonic explants. In addition, two of the strains showing high levels of Stx2 production and RBC lysis activity were associated with lethality and uremia in a mouse model. Consequently, circulation of such strains in cattle may partially contribute to the high incidence of HUS in Argentina.     

Remote sensing of phytoplankton-macrophyte coexistence in shallow hypereutrophic fluvial lakes

We investigated with remote sensing (APEX images) the coexistence of phytoplankton and macrophytes in three interconnected shallow and hypereutrophic fluvial lakes (Mantua Lakes, Northern Italy). High concentrations of chlorophyll-a, up to 60 mg m^?3, were determined in the open water between well-developed stands of floating-leaved, submerged, and emergent macrophytes. Our data suggest a general inhibition of phytoplankton by macrophytes, evidenced by decreasing chlorophyll-a concentrations in proximity of macrophyte stands. Chlorophyll-a concentrations halved in the proximity of emergent stands (~6 mg m^?3 within 21 m from the stand border) when compared to the outer zones (~13 mg m^?3). Contrasting trends were observed for submerged stands, where concentrations decreased inwards from ~8 to ~3 mg m^?3. Floating leaved stands had a neutral effect, chlorophyll-a being nearly constant in both inner and outer zones. Overall, remotely-sensed data allow evaluation of quantitative and spatially defined interactions of macrophytes and phytoplankton at the whole ecosystem scale.     

Altitudinal Patterns in Two Syntopic Species of Sturnira (Mammalia: Chiroptera: Phyllostomidae) in the Montane Rain Forests of Argentina

We evaluated altitudinal segregation in two Sturnira species as a mechanism allowing their coexistence. Tests were devised to discern between interspecific interactions and regional responses to geographic and environmental variables, using extensive capture data from 18 montane rain forest sites. No significant correlation between captures was found. Additionally and according to the hypothesis of historical occupation of highland versus lowland forests, each species has shown specificity in their response to the geographical and environmental variables. Our results indicated that abundance patterns in these bats likely result from the regional distribution of each species rather than local interactions between them, a pattern that may have ancient roots within the group.     

Gain of local structure in an amphipathic peptide does not require a specific tertiary framework

In this work, we studied how an amphipathic peptide of the surface of the globular protein thioredoxin, TRX94‐108, acquires a native‐like structure when it becomes involved in an apolar interaction network. We designed peptide variants where the tendency to form α‐helical conformation is modulated by replacing each of the leucine amino acid residues by an alanine. The induction of structure caused by sodium dodecyl sulfate (SDS) binding was studied by capillary zone electrophoresis, circular dichroism, DOSY‐NMR, and molecular dynamics simulations (MDS). In addition, we analyzed the strength of the interaction between a C18 RP‐HPLC matrix and the peptides. The results presented here reveal that (a) critical elements in the sequence of the wild‐type peptide stabilize a SDS/peptide supramolecular cluster; (b) the hydrophobic nature of the interaction between SDS molecules and the peptide constrains the ensemble of conformations; (c) nonspecific apolar surfaces are sufficient to stabilize peptide secondary structure. Remarkably, MDS shed light on a contact network formed by a limited number of SDS molecules that serves as a structural scaffold preserving the helical conformation of this module. This mechanism might prevail when a peptide with low helical propensity is involved in structure consolidation. We suggest that folding of peptides sharing this feature does not require a preformed tightly‐packed protein core. Thus, the formation of specific tertiary interactions would be the consequence of peptide folding and not its cause. In this scenario, folding might be thought of as a process that includes unspecific rounds of structure stabilization guiding the protein to the native state. Proteins 2010. © 2010 Wiley‐Liss, Inc.     

An experimental test of the defensive role of sticky traps in the carnivorous plant Pinguicula moranensis (Lentibulariaceae)

It has been sustained that the sticky traps present in some carnivorous plants could have evolved from ancestor species bearing leaves covered with secreting glands formerly associated with a defensive function. In this study, we evaluated the interaction of the carnivorous plant Pinguicula moranensis with its insect herbivores to assess the defensive role of the glandular trichomes. Firstly, we estimated the standing levels of insect herbivory in field conditions. We also evaluated the response of herbivore insects to the removal of the secreting glands from the leaves of P. moranensis in field and laboratory conditions. The mean damage was 1.61%, and half of the sampled plants showed no damage. The low level of herbivory in the field suggests that P. moranensis has an efficient defense ability. In the field experiment, after 25 d of exposure to natural damage, treated glandless plants received 18 times more damage than control plants. In the laboratory, the consumption of glandless tissue was three times higher during a 6 h evaluation period. Overall, our results provide evidence that secreting trichomes in Pinguicula are not only associated with prey capture but also have a defensive role. The defensive function could have favored the evolution of the sticky traps, the most extended prey‐capture strategy among carnivorous plants.     

Response of ‘Clausellina’ Satsuma mandarin to 3,5,6-trichloro-2-pirydiloxyacetic acid and fruitlet abscission

The application of the synthetic auxin 3,5,6-trichloro-2-piridyloxyacetic acid (3,5,6-TPA) isopropyl ester at the onset of cell enlargement stage, significantly thinned fruitlets in ‘Clausellina’ Satsuma mandarin. The magnitude of the response was related to the concentration applied, increasing the percentage of abscised fruit with higher concentrations, which was up to 70% at 25 mg l⁻¹. The magnitude of the response also depended on the organ subject to treatment, abscission being greater when applied to the leaves rather than to fruit. Results suggest that a photosynthetic disorder was responsible for a reduction in fruit growth rate, triggering abscission mechanisms producing ethylene and abscission.     

Knocking down the diencephalic thyrotropin-releasing hormone precursor gene normalizes obesity-induced hypertension in the rat

We recently showed that diencephalic TRH may mediate the central leptin-induced pressor effect. Here, to study the role of TRH in obesity-induced hypertension (OIH), we used a model of OIH produced by a high-fat diet (HFD, 45 days) in male Wistar rats. After 4 wk, body weight and systolic arterial blood pressure (SABP) increased in HFD animals. Plasma leptin was correlated with peritoneal adipose tissue. Then, we treated OIH animals with an antisense oligodeoxynucleotide and small interfering (si)RNA against the prepro-TRH. Antisense significantly decreased diencephalic TRH content and SABP at 24 and 48 h posttreatment. Similar effects were observed with siRNA against prepro-TRH but for up to 4 wk. Conversely, vehicle, an inverted antisense sequence and siRNA against green fluorescence protein, produced no changes. SABP decrease seems to be owing to an inhibition of the obesity-enhanced sympathetic outflow but not to an alteration in thyroid status. Using a simple OIH model we demonstrated, for the first time, that central TRH participates in the hypertension induced by body weight gain probably through its well-known action on sympathetic activity. Thus the TRH-leptin interaction may contribute to the strong association between hypertension and obesity.     

The influence of artificial cranial vault deformation on the expression of cranial nonmetric traits: its importance in the study of evolutionary relationships

Nonmetric cranial traits have been commonly used in evolutionary relationship studies. They develop during the growth and development of an individual, and for this reason its expression presents different sources of genetic and nongenetic variation. However, the use of these features in evolutionary relationship studies carries the implicit assumption that much of the nonmetric trait variation is essentially genetic. Among the nonheritable factors, cranial vault deformation has been the most studied in human populations. Because of the widespread distribution and elevated rate of artificial cranial vault deformation found in America, and the importance of nonmetric traits in evolutionary relationship studies in this area, the objectives of this paper are as follows: (a) to study the influence of artificial cranial vault deformation on the presence of nonmetric traits within samples of human craniofacial remains; and (b) to establish artificial cranial vault deformation influence on evolutionary relationships between local populations on a regional scale. Our results indicate that artificial cranial vault deformations alter the variation and covariation of metric and nonmetric traits in some samples. Wormian bones, placed in cranial vault sutures, are the most influenced by this factor. However, our results suggest that when all nonmetric traits were used the artificial cranial vault deformation did not influence the basic pattern of variation among samples. The exclusion or inclusion of wormians bones in evolutionary relationships analysis did not modify the results, but using only wormians bones lead to inconsistent results indicating that these traits have little value on these kind of studies.