Effect of chronic lithium on mechanical sensitivity and trabecular bone loss induced by type-1 diabetes mellitus in mice

BioMetals - Type-1 diabetes mellitus (T1DM) is a chronic condition characterized by long-term hyperglycemia that results in several complications such as painful peripheral neuropathy, bone...     

Do brassinosteroids alleviate water stress in seedlings of Handroanthus serratifolius?

Limited water availability in reforestation areas can compromise plant growth and development, especially for plants at early stages. In this context, the exogenous application of growth regulators, such as brassinosteroids (BRs), can be used to mitigate the negative effects of water restriction. The aim of this study was to evaluate the effect of the application of BRs (90% brassinolide + a brassinosteroid) on initial growth, gas exchange, leaf water potential and leaf anatomy in yellow Ipê (Handroanthus serratifolius), under water restriction conditions. Throughout the experimental period, plants were maintained in two different water regimes: WR1—plants maintained at 100% of the pot capacity; WR2—plants rehydrated with 50% of the evapotranspiration from the previous day. BRs were applied on three occasions during the experimental period, in five concentrations: C1, 0 g/L (application of distilled water); C2, 0.25 g/L; C3, 0.5 g/L; C4, 0.75 g/L; and C5, 1.00 g/L. The dry mass, root:shoot ratio, water status and leaf anatomy traits were evaluated at the end of the experimental period and were analysed in two-level factorial scheme (2WR × 5BRs concentrations). The plant height, number of leaves, gas exchange and leaf chlorophyll content were evaluated four times during the experimental period and were analysed in a split-split-plot design (two WR × five BRs concentrations × four evaluation times). The differences between the means were evaluated by analysis of variance (ANOVA). Pairs of means were separated using the standard error of the difference between the means (SED) and the Fisher's protected least significant difference test (LSD) at p < .05. In addition, all variables were subjected to regression analysis, being the variables evaluated over time, analysed through a two-stage modelling approach. The results obtained indicate that the water deficit led to reductions in growth and gas exchange parameters, regardless of the exogenous application of the regulator; therefore, higher concentrations (C4 and C5) were the most harmful for the maintenance of metabolic and photosynthetic activity. The exogenous application of BRs in H. serratifolius plants attenuated the effects of water limitation on the leaf water potential, but was not able to mitigate for the negative effects in growth, gas exchange and leaf anatomy.     

卷尾猴的卵泡生长发育及排卵的超声监测

目的建立卷尾猴正常月经周期卵泡生长发育变化规律及排卵的超声监测(ultrasound examination,US)技术。方法采用阴道细胞涂片及超声监测技术,对5只卷尾猴连续3个周期检查阴道细胞变化,对卵泡生长发育进行超声监测。结果阴道脱落细胞在生殖周期内呈周期性变化,月经周期为(21.13±2)d。阴道细胞学涂片显示卷尾猴的月经周期分为以下各期:月经期(menstrual phase,M)、滤泡期(follicular phase,F)、排卵前期(pre-ovulationphase,Po),黄体期(luteal phase,L)。US技术在滤泡期及排卵前期可观测到直径约3~9 mm的优势卵泡(dominantfollicle,DF)的生长过程。当DF较前一天至少小10%,轮廓不规则,回声较以前强,阴道细胞涂片显示淋巴细胞出现,提示排卵已发生,黄体开始形成。结论B型超声技术能实时监测卷尾猴的卵泡生长发育过程,预知优势卵泡排卵时间。     

Elaboration of B gene function to include the identity of novel floral organs in the lower eudicot Aquilegia

The basal eudicot Aquilegia (columbine) has an unusual floral structure that includes two morphologically distinct whorls of petaloid organs and a clearly differentiated fifth organ type, the staminodium. In this study, we have sought to determine how Aquilegia homologs of the B class genes APETALA3 (AP3) and PISTILLATA (PI) contribute to these novel forms of organ identity. Detailed expression analyses of the three AP3 paralogs and one PI homolog in wild-type and floral homeotic mutant lines reveal complex patterns that suggest that canonical B class function has been elaborated in Aquilegia. Yeast two-hybrid studies demonstrate that the protein products of Aquilegia's AP3 and PI homologs can form heterodimers, much like what has been observed for their core eudicot homologs. Downregulation of AqvPI using virus-induced gene silencing indicates that in addition to petal and stamen identity, this locus is essential to staminodial identity but may not control the identity of the petaloid sepals. Our findings show that preexisting floral organ identity programs can be partitioned and modified to produce additional organ types. In addition, they indicate that some types of petaloid organs are not entirely dependent on AP3/PI homologs for their identity.     

Molecular evolution of the petal and stamen identity genes, APETALA3 and PISTILLATA, after petal loss in the Piperales

Organ loss is an evolutionary phenomenon commonly observed in all kinds of multicellular organisms. Across the angiosperms, petals have been lost several times over the course of their diversification. We examined the evolution of petal and stamen identity genes in the Piperales, a basal lineage of angiosperms that includes the perianthless (with no petals or sepals) families Piperaceae and Saururaceae as well as the Aristolochiaceae, which exhibit a well-developed perianth. Here, we provide evidence for relaxation of selection on the putative petal and stamen identity genes, homologs of APETALA3 and PISTILLATA, following the loss of petals in the Piperales. Our results are particularly interesting as the B-class genes are not only responsible for the production of petals but are also central to stamen identity, the male reproductive organs that show no modification in these plants. Relaxed purifying selection after the loss of only one of these organs suggests that there has been dissociation of the functional roles of these genes in the Piperales.     

Relationship between Helicobacter pylori virulence factors and regulatory cytokines as predictors of clinical outcome

Helicobacter pylori infection is highly prevalent in Chile (73%). Usually a minority of infected patients develops complications such as ulcers and gastric cancer that have been associated with the presence of virulence factors (cagA, vacA) and host T helper response (Th1/Th2). Our aim was to evaluate the relationship between strain virulence and host immune response, using a multiple regression approach for the development of a model based on data collected from H. pylori infected patients in Chile. We analyzed levels of selected cytokines determined by ELISA (interleukin (IL)-12, IL-10, interferon (IFN)-gamma and IL-4) and the presence of cagA and vacA alleles polymorphisms determined by PCR in antral biopsies of 41 patients referred to endoscopy. By multiple regression analysis we established a correlation between bacterial and host factors using clinical outcome (gastritis and duodenal ulcer) as dependent variables. The selected model was described by: clinical outcome=0.867491 (cagA)+0.0131847 (IL-12/IL-10)+0.0103503 (IFN-gamma/IL-4) and it was able to explain over 90% of clinical outcomes observations (R(2)=96.4). This model considers that clinical outcomes are better explained by the interaction of host immune factors and strain virulence as a complex and interdependent mechanism.     

Bacillus thuringiensis ssp. israelensis Cyt1Aa enhances activity of Cry11Aa toxin by facilitating the formation of a pre-pore oligomeric structure

Bacillus thuringiensis ssp. israelensis (Bti) has been used worldwide for the control of dipteran insect pests. This bacterium produces several Cry and Cyt toxins that individually show activity against mosquitoes but together show synergistic effect. Previous work demonstrated that Cyt1Aa synergizes the toxic activity of Cry11Aa by functioning as a membrane-bound receptor. In the case of Cry toxins active against lepidopteran insects, receptor interaction triggers the formation of a pre-pore oligomer that is responsible for pore formation and toxicity. In this work we report that binding of Cry11Aa to Cyt1Aa facilitates the formation of a Cry11Aa pre-pore oligomeric structure that is capable of forming pores in membrane vesicles. Cry11Aa and Cyt1A point mutants affected in binding and in synergism had a correlative effect on the formation of Cry11Aa pre-pore oligomer and on pore-formation activity of Cry11Aa. These data further support that Cyt1Aa interacts with Cry11Aa and demonstrate the molecular mechanism by which Cyt1Aa synergizes or suppresses resistance to Cry11Aa, by providing a binding site for Cry11Aa that will result in an efficient formation of Cry11Aa pre-pore that inserts into membranes and forms ionic pores.     

A systematic quantification of carbonic anhydrase transcripts in the mouse digestive system

Background  

Carbonic anhydrases (CAs) are physiologically important enzymes which participate in many gastrointestinal processes such as acid and bicarbonate secretion and metabolic pathways including gluconeogenesis and ureagenesis. The genomic data suggests that there are thirteen enzymatically active members of the mammalian CA isozyme family. In the present study, we systematically examined the mRNA expression levels of all known CA isozymes by quantitative real-time PCR in eight tissues of the digestive system of male and female mice.     

Toxicity of Bacillus thuringiensis delta-endotoxins against bean shoot borer (Epinotia aporema Wals.) larvae, a major soybean pest in Argentina

The toxicity of seven Bacillus thuringiensis Cry protoxins was tested against neonate larvae of Epinotia aporema, a major soybean pest in Argentina and South America. The most active protoxins were Cry1Ab and Cry1Ac, with LC50 values of 0.55 and 1.39 microg/ml, respectively. Cry1Aa, Cry1Ba, Cry1Ca, and Cry9Ca protoxins were equally toxic with LC50 values about 4 microg/ml, whereas Cry1Da was not toxic. The synergistic activity of different protoxin-mixtures was also analyzed, no synergistic effect between the Cry proteins was observed, with the exception of the poorly toxic Cry1Ba/Cry1Da mixture that was slightly synergistic. The binding capacity of individual Cry1 and Cry9Ca toxins to brush border membranes of E. aporema was also determined. The non-toxic Cry1Da toxin was the only toxin unable to bind to E. aporema membranes. In addition the heterologous competition experiments showed that Cry1Ab and Cry1Ac toxins share a common binding site. Based on these data, we propose that Cry1Ab and Cry1Ac toxins could be used in the biological control of E. aporema.     

Effect of steroid hormones on Bufo arenarum oviduct. Ultrastructural study

The endocrine regulation of the mucosa of the oviductal pars convoluta was analyzed by ultrastructural studies demonstrating that ovariectomy, together with a decrease in ovarian steroids circulating levels, caused a marked regression in this portion of Bufo arenarum oviduct. Twenty-five days after ovariectomy, a decrease in the depth of the epithelial and glandular layers was observed due to the notable loss of secretory cells, whose number was clearly smaller than in nonovariectomized females. The remaining secretory cells showed involution signs, with few secretory granules in their cytoplasm, little endoplasmic reticulum near poorly developed Golgi complexes and a large amount of lipid droplets. Cells in an advanced autolysis state were found in the lumen. These characteristics evidence a nonfunctional state of the pars convoluta. Treatment with 5alpha-dihydrotestosterone (DHT) completely reversed the ovariectomy effect, inducing pars convoluta growths and restoring the characteristics of epithelial and glandular secretory cells in the whole pars convoluta, with micrographs similar to the control. These same effects were observed after treatment with estradiol-17beta (E2), progesterone (P) o E(2)+P in the glandular layer of the whole pars convoluta, but only in the epithelial layer of the most anterior region of this duct. In the secretory cells of other segments these treatments induced the formation of granules of high electron density and homogeneous aspect. Each steroid had a particular effect on the pars convoluta. Although E2 and DHT induced the development of the organoids involved in the proteins biosynthesis, P and DHT acted as secretagogues.