Aquaporins influence seed dormancy and germination in response to stress

Aquaporins influence water flow in plants, yet little is known of their involvement in the water‐driven process of seed germination. We therefore investigated their role in seeds in the laboratory and under field and global warming conditions. We mapped the expression of tonoplast intrinsic proteins (TIPs) during dormancy cycling and during germination under normal and water stress conditions. We found that the two key tonoplast aquaporins, TIP3;1 and TIP3;2, which have previously been implicated in water or solute transport, respectively, act antagonistically to modulate the response to abscisic acid, with TIP3;1 being a positive and TIP3;2 a negative regulator. A third isoform, TIP4;1, which is normally expressed upon completion of germination, was found to play an earlier role during water stress. Seed TIPs also contribute to the regulation of depth of primary dormancy and differences in the induction of secondary dormancy during dormancy cycling. Protein and gene expression during annual cycling under field conditions and a global warming scenario further illustrate this role. We propose that the different responses of the seed TIP contribute to mechanisms that influence dormancy status and the timing of germination under variable soil conditions.     

Discrimination between extreme chronotypes using the full and reduced version of the Morningness-Eveningness Questionnaire

The aim of this study was to carry out a comparison of the ability to discriminate between extreme chronotypes, i.e., morning- and evening-types, among the Morningness-Eveningness Questionnaire (MEQ) and its reduced version (rMEQ). To this end a secondary analysis of cohort studies, using two different approaches, was carried out. The first, subjective, relied on the computing of overlap between extreme chronotypes according to their hourly ideal bedtime, get-up time and midpoint of sleep reported at the MEQ and rMEQ, while the second, objective, on the corresponding actual-actigraphic times. At the subjective approach, 2706 participants filled in the MEQ, while 940 the rMEQ (age range of both groups: 18–30 years). The overlap was significantly lower among those who filled the rMEQ than MEQ when considering ideal midpoint of sleep (13.70% and 46.28%, respectively) and get-up time (47.04% and 62.34%, respectively). At the objective approach, 51 participants filled in the MEQ while 52 the rMEQ (age range: 19–30 years in both groups) at the end of one week of actigraphic recording. No significantly different overlap across those who filled the MEQ or rMEQ was observed with reference to the examined actigraphic times. Results of subjective assessment showed as rMEQ more clearly discriminated between extreme chronotypes than MEQ. The attempt to find an objective confirmation did not provide the same results, probably as a consequence of a masking effect by social rhythms.     

Semisynthetic Triterpenes Derived from Euphorbia officinarum as Plant Growth Promoters and Inducers of Disease Resistance

This study evaluated the effect of application of the semisynthetic triterpenes 3β-acetoxy-norlup-20-one (F4) and 3-chloro-4α,14α-dimethyl-5α-cholest-8-ene (F6) triterpene derivatives from Euphorbia officinarum on the growth of tomato seedlings under normal conditions and when challenged with the pathogens Verticillium dahliae and Agrobacterium tumefaciens. Foliar spray of F4 and F6 significantly improved growth rate, fresh weight, dry weight, and leaf area. In addition, they enhanced several physiological parameters including photosynthetic pigments, proline content, and nitrate reductase activity. Moreover, they induced H₂O₂ accumulation and increased the activity of several antioxidant enzymes such as catalase, ascorbate peroxidase, and guaiacol peroxidase. They also enhanced disease resistance against V. dahliae and A. tumefaciens. These results suggest that the two semisynthetic triterpenes represent new plant growth regulators and inducers of plant disease resistance.

     

Phosphorylation of NHERF1 S279 and S301 differentially regulates breast cancer cell phenotype and metastatic organotropism

Metastatic cancer cells are highly plastic for the expression of different tumor phenotype hallmarks and organotropism. This plasticity is highly regulated but the dynamics of the signaling processes orchestrating the shift from one cell phenotype and metastatic organ pattern to another are still largely unknown. The scaffolding protein NHERF1 has been shown to regulate the expression of different neoplastic phenotypes through its PDZ domains, which forms the mechanistic basis for metastatic organotropism. This reprogramming activity was postulated to be dependent on its differential phosphorylation patterns. Here, we show that NHERF1 phosphorylation on S279/S301 dictates several tumor phenotypes such as in vivo invasion, NHE1-mediated matrix digestion, growth and vasculogenic mimicry. Remarkably, injecting mice with cells having differential NHERF1 expression and phosphorylation drove a shift from the predominantly lung colonization (WT NHERF1) to predominately bone colonization (double S279A/S301A mutant), indicating that NHERF1 phosphorylation also acts as a signaling switch in metastatic organotropism.     

Transforming growth factor β1 induces mitogenesis in fetal rat brown adipocytes

The presence of transforming growth factor β₁ (TGF-β₁) for 24 or 48 h stimulated DNA synthesis, the percentage of cells in the S + G₂/M phases of the cell cycle, and cell number, as compared to quiescent cells. The mitogenic capacity of TGF-β₁ (1 pM) was similar to that shown by 10% fetal calf serum (FCS). TGF-β₁ for 48 h increased by 5-fold the percentage of cells containing (³H)thymidine-labeled nuclei as compared to quiescent cells. In addition, single fetal brown adipocytes, showing their typical multilocular fat droplets phenotype, become positive for (³H)thymidine-labeled nuclei in response to TGF-β₁. Moreover, TGF-β₁ induced the mRNA expression of a complete set of proliferation-related genes, such as c-fos (30 min), c-myc and β-actin (2 h), and H-ras, cdc2 kinase, and glucose 6-phosphate dehydrogenase (G6PD) at 4 and 8 h, as compared to quiescent cells. Concurrently, TGF-β₁ for 12 h increased the protein content of proliferating cellular nuclear antigen (PCNA) by 6-fold and p21-ras by 2-fold. Although our results demonstrate that TGF-β₁ induces the expression of very early genes related to cell proliferation, TGF-β₁ could be acting either as a mitogen or as a survival factor to induce proliferation in fetal brown adipocytes. © 1996 Wiley-Liss, Inc.     

Analysis of oscillations in yeast continuous cultures by a new simplified model

The autonomous oscillations in yeast continuous cultures are investigated analytically and related to the behaviour of the single cell by means of a suitable modified version of Monod’s classical chemostat model. Two main cell phases or states are considered to account for the experimentally observed changes occurring in the cell growth course: the budded phase and the unbudded one. Thus, a sort of two compartment structure is given to the total biomass. The model so far obtained allows one to analyse the local properties of the predicted steady states under various assumptions, both on the yield coefficients and the specific growth rates. Necessary conditions for the local instability are derived and the existence of stable limit cycles is shown by computer simulation. With respect to the qualitative changes in the metabolic parameters, this analysis agrees with the results obtained by simulation of complex structured and segregated models. However, the oscillation period is too long compared with the experimental one and this fact may be mainly due to the strong simplifying assumptions on the dynamic evolution of the transfer rates between the two compartments. The model’s usefulness seems until now restricted to the identification of the relationships between the cell cycle regulation and the oscillation triggering.     

Neurosecretory and trophic action on fetal rat neuroblasts induced by an amino acid mixture

The effects of a synthetically obtained mixture of amino acids (FACE) were investigated on the trophic and neurosecretory activity of in vitro cultures of fetal rat neuronal cells. The addition of 10(-6) M FACE to the culture medium significantly increased cell DNA content. Secretions of IR-SRIF, IR-VIP, and IR-GRF were also augmented in different proportions by the presence of FACE. Time studies demonstrated that IR-SRIF was significantly increased after 48 (P less than 0.05) and 72 (P less than 0.01) hr of exposure to FACE, and IR-VIP secretion was potentiated after only 24 hr of culture. Dose-response experiments with 10(-7) to 10(-4) M FACE indicated that concentrations of 10(-5) and 10(-4) M significantly increased both somatostatin released to the medium and cell content of IR-SRIF. FACE concentrations as low as 10(-10) M augmented the secretion of IR-GRF, and there was a dose-response correlation between 10(-10) and 10(-5) M FACE. The release and cell content of IR-VIP were also increased by FACE, with a dose-response relation at concentrations of 10(-9) to 10(-6) M. It can thus be concluded that FACE has a powerful effect on the multiplication and survival of fetal cerebrocortical cells and is also an important potentiator of IR-SRIF, IR-VIP, and IR-GRF secretion.     

Schwannomas of the peroneal nerves: Clinical and functional results of surgical treatment

Objectives:Peroneal nerves Schwannomas are rare benign tumors. Literature is still poor of studies about clinical and functional outcomes after surgical treatment. We evaluated the pre-operative presentation of the disease and assessed clinical and functional outcomes after surgery.Methods:We collected all the cases of peroneal nerves’ neurinoma treated surgically between June 2016 and June 2020. We analyzed each patients’ personal data and carried out accurate clinical examinations before and after surgery. MRI was performed both pre-operatively and post-operatively.Results:We reported 9 cases of peroneal nerves schwannomas: five arising from the common peroneal nerve and four arising from the deep or superficial branches alone. Their mean size was 22.6 mm. Each patient showed sensation deficits before surgery; pre-operative MRC score was 4.2. Pre-Operative MSTS and LEFS scores were 23.6 and 64.4. Surgery was successful in each case. No local recurrence nor major complication occurred. Tumor size was significantly associated with both diagnostic delay and development of pre-operative deficits. Surgery was proven to be globally successful: post-operative evaluations highlighted a marked reduction of neurological signs and overall functional limitations.Conclusions:Surgical treatment at early stages of the disease represents a reliable and relatively safe therapeutic option.     

Body size of insular carnivores: evidence from the fossil record

Aim Our goals here are to: (1) assess the generality of one aspect of the island rule – the progressive trend towards decrease in size in larger species – for fossil carnivores on islands; (2) offer causal explanations for this pattern and deviations from it – as far as fossil carnivores are concerned; and (3) estimate the speed of this trend. Location Oceanic and oceanic‐like islands world‐wide. Methods Body size estimates of fossil insular carnivores and of their phylogenetically closest mainland relative were obtained from our own data and the published literature. Our dataset consisted of 18 species from nine islands world‐wide. These data were used to test whether the body size of fossil insular carnivores varies as a function of body size of the mainland species in combination with characteristics of the island ecosystem. Results Dwarfism was observed in two canid species. Moderate decrease in body mass was observed in one hyena species. Gigantism was observed in one otter species. Moderate body mass increase was observed in two otter species, one galictine mustelid and perhaps one canid. Negligible or no change in body mass at all was observed in five otter species, three galictine mustelids and one genet. Size changes in teeth do not lag behind in comparison to skeletal elements in the dwarfed canids. The evolutionary speed of dwarfism in a canid lineage is low. Main conclusions Size change in fossil terrestrial insular carnivores was constrained by certain ecological conditions, especially the availability of prey of appropriate body size. When such alternative prey was not available, the carnivores retained their mainland size. The impact of competitive carnivores seems negligible. The case of (semi‐)aquatic carnivores is much less clear. The species that maintained their ancestral body mass may have changed their diet, as is evidenced by their dentition. Among the otters, one case of significant size increase was observed, perhaps best explained as being due to it entering the niche of an obligate aquatic otter. Dwarfism was not observed in otters. The island rule seems to apply to fossil carnivores, but with exceptions. The dependency of the island rule on resource availability is emphasized by the present study.