Ecological factors affecting eruption timing of mandibular teeth in roe deer

Increasing evidence suggests that conditions in early life have important consequences for body size and fitness in mammals. As regards herbivores, teeth play a central role in the long-term performance of individuals. So far, however, patterns of teeth eruption have been scarcely investigated in relation to environmental and climatic factors experienced by herbivores. We described the eruption timing of mandibular teeth in a population of roe deer (Capreolus capreolus) located in the Apennines (Central Italy), through the analysis of 2161 jaws of fawns (1176 females and 985 males) shot in their first winter of life over three hunting seasons (2013–2015). Results showed that the percentage of juveniles exhibiting permanent teeth depends on the cohort. Among the factors that may affect both incisiviform and molariform teeth replacement timing, our findings include body mass and population density. Additional factors determining the relative speed of teeth replacement are (1) food availability for the mother during the last part of gestation, the birth period and the lactation, (2) winter temperature experienced by the mother, and (3) temperature experienced by fawns during their first summer and autumn. Besides, for the first time in literature, elevation was reported to delay front teeth replacement. A greater number of climatic factors were found to shape the eruption timing of the third molar (M₃) in comparison to that of incisiviform teeth. Also, a different pattern was found in males and females. The eruption of M₃ is, indeed, a costly and long-lasting process requesting optimal nutritional conditions and the meeting of a threshold jaw size. Our results indicate a strong correlation between environmental conditions and eruption process, i.e., between resource availability during the gestation and rearing periods and eruption timing.     

Extinct,obscure or imaginary: The lizard species with the smallest ranges

Aim

Small geographic ranges make species especially prone to extinction from anthropogenic disturbances or natural stochastic events. We assemble and analyse a comprehensive dataset of all the world's lizard species and identify the species with the smallest ranges—those known only from their type localities. We compare them to wide‐ranging species to infer whether specific geographic regions or biological traits predispose species to have small ranges.

Location

Global.

Methods

We extensively surveyed museum collections, the primary literature and our own field records to identify all the species of lizards with a maximum linear geographic extent of <10 km. We compared their biogeography, key biological traits and threat status to those of all other lizards.

Results

One in seven lizards (927 of the 6,568 currently recognized species) are known only from their type localities. These include 213 species known only from a single specimen. Compared to more wide‐ranging taxa, they mostly inhabit relatively inaccessible regions at lower, mostly tropical, latitudes. Surprisingly, we found that burrowing lifestyle is a relatively unimportant driver of small range size. Geckos are especially prone to having tiny ranges, and skinks dominate lists of such species not seen for over 50 years, as well as of species known only from their holotype. Two‐thirds of these species have no IUCN assessments, and at least 20 are extinct.

Main conclusions

Fourteen per cent of lizard diversity is restricted to a single location, often in inaccessible regions. These species are elusive, usually poorly known and little studied. Many face severe extinction risk, but current knowledge is inadequate to properly assess this for all of them. We recommend that such species become the focus of taxonomic, ecological and survey efforts.

     

The dynamics of recalcitrant seed banks of <Emphasis Type="Italic">Mauritia flexuosa</Emphasis> (Arecaceae) reveal adaptations to marsh microenvironments

The Mauritia flexuosa palm tree is widely distributed in South America, and is associated with flooded environments. It dominates the arboreal stratum in the highly threatened marsh ecosystems called “veredas” in the Cerrado biome (neotropical savanna), and its oleaginous fruits are important for the maintenance of the regional fauna and as a source of income for traditional human populations. The seeds of this palm demonstrate an unusual association of recalcitrance and dormancy, and information about its seed bank maintenance in natural environments is scarce. We measured the variations in water content, viability, and germination of seeds maintained over 1 year in four typical vereda microenvironments (edge, near the water, in the water, and at the lower zone of the vereda) and related that information to soil water contents and climatic data. Seed viability was best preserved under constantly flooded conditions (at the lower zone of the vereda), with the potential for maintaining a temporary seed bank in the aquatic environment that would favor dispersal. Although the seeds are intolerant of dehydration, they have a high capacity for maintaining their water contents under partially drained soil conditions, and overcoming dormancy is favored under those conditions. Mauritia flexuosa establishment strategies are driven by sophisticated interactions with climate and with vereda microenvironments, with a tendency for maintaining seed banks and seedling banks in localities with flooded or drained soils, respectively.     

Skeletal muscle dispersion (400‐1000 nm) and kinetics at optical clearing

Skeletal muscle dispersion and optical clearing (OC) kinetics were studied experimentally to prove the existence of the refractive index (RI) matching mechanism of OC. Sample thickness and collimated transmittance spectra were measured during treatments with glucose (40%) and ethylene glycol (EG; 99%) solutions and used to obtain the time dependence of the RI of tissue fluids based on the proposed theoretical model. Calculated results demonstrated an increase of RI of tissue fluids and consequently proved the occurrence of the RI matching mechanism. The RI increase was observed for the wavelength range between 400 and 1000 nm and for the 2 probing molecules explored. We found that for 30 min treatment with 40% glucose and 99% EG, RI of sarcoplasm plus interstitial fluid was increased at 800 nm from 1.328 to 1.348 and from 1.328 to 1.369, respectively.      

Impacts of soybean-induced defenses on <Emphasis Type="Italic">Spodoptera frugiperda</Emphasis> (Lepidoptera: Noctuidae) development

As soybean (Glycine max [L.] Merrill) is an important crop throughout the world, the action of herbivorous insects responsible for economic and productivity losses is the subject of constant research. Spodoptera frugiperda (J.E. Smith) caterpillars can cause extensive damage to soybean culture; this work investigated possible harmful effects on these caterpillars associated with the possible induced defenses of soybean plants. For this purpose, we assessed the biology of the insect (leaf consumption and performance traits) and chemical composition of the soybean leaves by ultraviolet–visible spectroscopy and chemometrics of three treatments: control, mechanically wounded soybean leaves, and S. frugiperda-damaged soybean leaves. The results reveal that both types of injuries induce changes in soybean metabolism regarding the production of phenolic substances, although only the herbivore-damaged plants provoke negative effects on insect biology. Variations in carotenoid production during the circadian cycle were also found in the control group. These results confirm that the soybean plants could endure and activate chemical defense mechanisms that impair the developmental lifecycle of the insect, suggesting possibilities for sustainable control strategies.     

Cellulose synthase ‘class specific regions’ are intrinsically disordered and functionally undifferentiated

Cellulose synthases(CESAs) are glycosyltransferases that catalyze formation of cellulose microfibrils in plant cell walls.Seed plant CESA isoforms cluster in six phylogenetic clades, whose non-interchangeable members play distinct roles within cellulose synthesis complexes(CSCs).A ‘class specific region’(CSR), with higher sequence similarity within versus between functional CESA classes, has been suggested to contribute to specific activities or interactions of different isoforms.We investigated CESA isoform specificity in the moss,Physcomitrella patens(Hedw.) B.S.G.to gain evolutionary insights into CESA structure/function relationships.Like seed plants, P.patens has oligomeric rosette-type CSCs, but the Pp CESAs diverged independently and form a separate CESA clade.We showed that P.patens has two functionally distinct CESAs classes, based on the ability to complement the gametophore-negative phenotype of a ppcesa5 knockout line.Thus, non-interchangeable CESA classes evolved separately in mosses and seed plants.However, testing of chimeric moss CESA genes for complementation demonstrated that functional classspecificity is not determined by the CSR.Sequence analysis and computational modeling showed that the CSR is intrinsically disordered and contains predicted molecular recognition features, consistent with a possible role in CESA oligomerization and explaining the evolution of class-specific sequences without selection for class-specific function.     

A novel functional crosstalk between DDR1 and the IGF axis and its relevance for breast cancer

ABSTRACT

In the last decades increasing importance has been attributed to the Insulin/Insulin-like Growth Factor signaling (IIGFs) in cancer development, progression and resistance to therapy. In fact, IIGFs is often deregulated in cancer. In particular, the mitogenic insulin receptor isoform A (IR-A) and the insulin-like growth factor receptor (IGF-1R) are frequently overexpressed in cancer together with their cognate ligands IGF-1 and IGF-2. Recently, we identified discoidin domain receptor 1 (DDR1) as a new IR-A interacting protein. DDR1, a non-integrin collagen tyrosine kinase receptor, is overexpressed in several malignancies and plays a role in cancer progression and metastasis.

Herein, we review recent findings indicating that DDR1 is as a novel modulator of IR and IGF-1R expression and function. DDR1 functionally interacts with IR and IGF-1R and enhances the biological actions of insulin, IGF-1 and IGF-2. Conversely, DDR1 is upregulated by IGF-1, IGF-2 and insulin through the PI3K/AKT/miR-199a-5p circuit. Furthermore, we discuss the role of the non-canonical estrogen receptor GPER1 in the DDR1-IIGFs crosstalk. These data suggest a wider role of DDR1 as a regulator of cell response to hormones, growth factors, and signals coming from the extracellular matrix.     

CXCL12 chemokine and CXCR4 receptor: association with susceptibility and prognostic markers in triple negative breast cancer

CXCL12/CXCR4 signaling has been implicated in breast carcinogenesis, and genetic polymorphisms in these molecules have been associated with different types of cancer. The present study analyzed genetic polymorphisms in CXCL12 (rs1801157, G?>?A) and CXCR4 (rs2228014, C?>?T) and CXCR4 immunostaining in tumor tissues from patients with triple negative breast cancer (TNBC) aiming to evaluate their possible role in its’ susceptibility and prognosis. Genetic polymorphisms were analyzed in 59 TNBC patients and 150 control women; age-adjusted logistic regression showed no association when variants were considered in isolation; however, a statistically significant interaction was noted for heterozygosis for both allelic variants increasing the odds for TNBC (CXCL12-GA by CXCR4-CT: OR 7.23; 95% CI 1.15–45.41; p?=?0.035). CXCL12 polymorphism was correlated negatively with proliferation index (Ki67) (Tau-b?=???0.406; p?=?0.006). CXCR4 immunostaining was evaluated in 37 TNBC patients (22 with paired tumor-normal adjacent tissue). CXCR4 was detected more intensely in cell cytoplasm than in membrane, and was more expressed in tumor than in normal adjacent tissues, although not statistically significant. CXCR4 expression on the membrane of tumor cells was correlated positively with histopathological grade (Tau-b?=?0.271; p?=?0.036) and negatively with lymph node metastasis (Tau-b?=???0.478; p?=?0.036). The present study indicates that CXCL12 and CXCR4 polymorphisms and CXCR4 immunostaining might have susceptibility and prognostic roles in TNBC pathogenesis.