Geographic isolation affects inter- and intra-specific seed variability in the Astragalus tragacantha complex,as assessed by morpho-colorimetric analysis

The effect of geographical isolation on the inter- and intra-specific seed variability of the Astragalus tragacantha complex was investigated by using a computer-aided imaging system. In particular, seed morphometric and colorimetric features of Astragalus balearicus, A. tegulensis, A. terraccianoi, A. thermensis and A. tragacantha were measured and the data were used to discriminate among regions of provenance, taxa and populations. Discriminant analysis of the data supports the accepted taxonomy of the group and the hypothesis that interspecific differentiation resulted from geographical isolation. The results also showed a positive correlation between the wideness of species’ distribution and the levels of seed intra-specific variability.     

Altered Glucose Homeostasis Is Associated with Increased Serum Apelin Levels in Type 2 Diabetes Mellitus

Background

Apelin is an adipokine that plays a role in the regulation of glucose homeostasis and in obesity. The relationship between apelin serum concentration and dysmetabolic conditions such as type 2 diabetes (T2D) is still controversial. Aims of our study are: 1) determine the circulating levels of apelin in a large cohort of Italian subjects with T2D, T1D and in non-diabetic controls; 2) identify putative metabolic determinants of modified apelin concentrations, in order to search possible mechanism of apelin control; 3) investigate changes in apelin levels in response to sharp modifications of glucose/insulin metabolism in T2D obese subjects before and 3 days after bariatric surgery.

Methods

We recruited 369 subjects, 119 with T2D, 113 with T1D and 137 non-diabetic controls. All subjects underwent a complete clinical examination, including anthropometric and laboratory measurements. Serum apelin levels were determined by EIA (immunoenzyme assay).

Results

Patients with T2D had significantly higher serum apelin levels compared to controls (1.23±1.1 ng/mL vs 0.91±0.7 ng/mL, P<0.001) and to T1D subjects (0.73±0.39 ng/mL, P<0.001). Controls and T1D subjects did not differ significantly in apelin levels. Apelin concentrations were directly associated with fasting blood glucose (FBG), body mass index (BMI), basal Disposition Index (DI-0), age, and diagnosis of T2D at bivariate correlation analysis. Multiple regression analysis confirmed that diagnosis of T2D, basal DI-0 and FBG were all determinants of serum apelin levels independently from age and BMI. Bariatric surgery performed in a subgroup of obese diabetic subjects (n = 12) resulted in a significant reduction of apelin concentrations compared to baseline levels (P = 0.01).

Conclusions

Our study demonstrates that T2D, but not T1D, is associated with increased serum apelin levels compared to non-diabetic subjects. This association is dependent on impaired glucose homeostasis, and disappears after bariatric surgery, providing further evidence regarding the relationship between apelin and the regulation of glucose metabolism.     

The regulatory elements of araBAD operon,contrary to lac‐based expression systems,afford hypersynthesis of murine,and human interferons in Escherichia coli

The overexpression of four different interferons, i.e., murine interferon α1 and human interferons α1, α8, and α21 was challenged in Escherichia coli. Synthetic genes coding for these interferons were designed, assembled, and cloned into the vector pET9a (using the NdeI and BamHI sites), placing interferon expression under the control of phage T7 promoter. Despite an intensive screening for optimal culture conditions, no interferon synthesis was observed using overexpression systems based on the regulatory elements of lac operon (e.g., in E. coli BL21DE3). On the contrary, high levels of interferon expression were detected in E. coli BL21AI, which chromosome contains the gene coding for phage T7 RNA polymerase under the control of the araBAD promoter. To analyze the reasons of this striking difference, the molecular events associated with the lack of interferon expression in E. coli BL21DE3 were studied, and murine interferon α1 was chosen as a model system. Surprisingly, it was observed that this interferon represses the synthesis of T7 RNA polymerase in E. coli BL21DE3 and, in particular, the expression of lac operon. In fact, by determining β‐galactosidase activity in E. coli BL21AI, a significantly lower LacZ activity was observed in cells induced to interferon synthesis. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009     

Effects of NaCl stress on seed germination and seedling development of Brassica insularis Moris (Brassicaceae)

• Brassica insularis is a protected plant that grows on both coastal and inland cliffs in the western Mediterranean Basin. The objective of this study was to test if any variability exists in the salt stress response during seed germination and seedling development in this species relative to its provenance habitat.
• Variability among three populations in the salt stress effects on seed germination and recovery under different temperatures was evaluated. The effect of nebulisation of a salt solution on seedling development was evaluated between populations growing at different distances from the sea.
• Seeds of B. insularis could germinate at NaCl concentrations up to 200 mm . Seed viability was negatively affected by salt, and recovery ability decreased with increasing temperature or salinity. Inter‐population variability was detected in salt response during the seed germination phase, as well as in seedling salt spray tolerance. The inland population seedlings had drastically decreased survival and life span and failed to survive to the end of the experiment. In contrast, at least 90% of the coastal seedlings survived, even when sprayed at the highest frequency with salt solution.
• This study allowed investigation of two natural factors, soil salinity and marine aerosols, widely present in the B. insularis habitat, and provided the first insights into ecology of this protected species and its distribution in the Mediterranean. These results might be useful in understanding the actual distributions of other species with the same ecology that experience these same abiotic parameters.

     

An Italian functional genomic resource for <Emphasis Type="Italic">Medicago truncatula</Emphasis>

Background

Medicago truncatula is a model species for legumes. Its functional genomics have been considerably boosted in recent years due to initiatives based both in Europe and US. Collections of mutants are becoming increasingly available and this will help unravel the genetic control of important traits for many species of legumes.

Findings

Our report is on the production of three complementary mutant collections of the model species Medicago truncatula produced in Italy in the frame of a national genomic initiative. Well established strategies were used: Tnt1 mutagenesis, TILLING and activation tagging. Both forward and reverse genetics screenings proved the efficiency of the mutagenesis approaches adopted, enabling the isolation of interesting mutants which are in course of characterization. We anticipate that the reported collections will be complementary to the recently established functional genomics tools developed for Medicago truncatula both in Europe and in the United States.

     

Delay of leaf senescence in <Emphasis Type="Italic">Medicago sativa</Emphasis> transformed with the <Emphasis Type="Italic">ipt</Emphasis> gene controlled by the senescence-specific promoter SAG12

We report the successfull delay of leaf senescence in Medicago sativa. A highly regenerable clone of alfalfa was transformed with the construct SAG12-IPT, an approach that has already proved efficient in other crops. Several independent transformants were obtained as determined by Southern analysis and all the transformants expressed the transgene as measured by RT-PCR. In vitro and in vivo analyses showed that SAG12-IPT plants exhibited a stay-green phenotype that has the potential to greatly improve the quantity and quality of alfalfa forage.     

Metal-catalyzed oxidation of extracellular matrix proteins promotes human mesangial cell apoptosis and is associated with enhanced expression of Bax and caspase activation

Oxidative injury in glomerular disease may oxidize extracellular matrix proteins which might modulate their interaction with mesangial cells and thereby account for the hypocellularity seen in advanced glomerulosclerosis. In this study we evaluated whether oxidation of extracellular matrix could modulate human mesangial cell apoptosis. Human mesangial cells were seeded onto plates coated with unmodified (control) or oxidized Matrigel, laminin, or type IV collagen. Mesangial cell apoptosis was increased on oxidized Matrigel as well as on oxidized laminin and type IV collagen. Mesangial cells behaved similarly on plates coated with control and oxidized forms of the integrin ligand-containing peptide GRGDSP. Cells on oxidized matrix demonstrated enhanced expression of Bax, increased fragmentation of PARP, and diminished apoptosis in the presence of the interleukin-1 beta converting enzyme inhibitor Ac-Tyr-Val-Ala-Asp-aldehyde. These data suggest that oxidation of extracellular matrix proteins may enhance human mesangial cell apoptosis via a mechanism that appears to involve enhanced expression of Bax and caspase activation. This may account for irreversible mesangial hypocellularity in glomerulosclerosis.