Adenosine mediates transforming growth factor-beta 1 release in kidney glomeruli of diabetic rats

Up regulation of the transforming growth factor-beta 1 (TGF-β1) axis has been recognized as a pathogenic event for progression of glomerulosclerosis in diabetic nephropathy. We demonstrate that glomeruli isolated from diabetic rats accumulate up to sixfold more extracellular adenosine than normal rats. Both decreased nucleoside uptake activity by the equilibrative nucleoside transporter 1 and increased AMP hydrolysis contribute to raise extracellular adenosine. Ex vivo assays indicate that activation of the low affinity adenosine A_2B receptor subtype (A_2BAR) mediates TGF-β1 release from glomeruli of diabetic rats, a pathogenic event that could support progression of glomerulopathy when the bioavailability of adenosine is increased.     

Salinity and germination of annual Melilotus from the Guadalquivir delta (SW Spain)

The germination response to NaCl treatments has been studied in Melilotus seed populations collected from saline and non-saline soils in the Guadalquivir delta. The rank orders for salt tolerance and seed weight were the same in the threeMelilotus species living in this area:Melilotus messanensis>M. segetalis>M. indica. Within the species, differences in germination response to salinity were found inM. indica (6 populations) andM. segetalis (8 populations). The relationship between salt tolerance during germination and salinity of maternal habitat is discussed.     

A descriptive study of some Antarctic notaspidean opisthobranchs (Gastropoda), with description of a new genus and species

During the expedition “ANTARTIDA 9101”, organized by the Spanish Oceanographic Institute to the South Orkney Islands, four specimens of notaspidean gastropods were collected. Three of them have been identified as Bathyberthella antarctica Willan and Bertsch, 1987. However, one specimen, although externally similar to B. antarctica, had an internal anatomy exhibiting features that have enabled us to consider it to be a new genus and species. This new taxon is characterized by the presence of jaws without mandibular elements, and a vaginal gland that partially surrounds the distal region of the vaginal duct. In this paper the new genus and species is described. Additional anatomical data of the specimens of B. antarctica collected during the expedition are also included.     

Patterns of sequence variation in the mitochondrial D-loop region of shrews

Direct sequencing of the mitochondrial displacement loop (D-loop) of shrews (genus Sorex) for the region between the tRNA(Pro) and the conserved sequence block-F revealed variable numbers of 79-bp tandem repeats. These repeats were found in all 19 individuals sequenced, representing three subspecies and one closely related species of the masked shrew group (Sorex cinereus cinereus, S. c. miscix, S. c. acadicus, and S. haydeni) and an outgroup, the pygmy shrew (S. hoyi). Each specimen also possessed an adjacent 76-bp imperfect copy of the tandem repeats. One individual was heteroplasmic for length variants consisting of five and seven copies of the 79-bp tandem repeat. The sequence of the repeats is conducive to the formation of secondary structure. A termination-associated sequence is present in each of the repeats and in a unique sequence region 5' to the tandem array as well. Mean genetic distance between the masked shrew taxa and the pygmy shrew was calculated separately for the unique sequence region, one of the tandem repeats, the imperfect repeat, and these three regions combined. The unique sequence region evolved more rapidly than the tandem repeats or the imperfect repeat. The small genetic distance between pairs of tandem repeats within an individual is consistent with a model of concerted evolution. Repeats are apparently duplicated and lost at a high rate, which tends to homogenize the tandem array. The rate of D- loop sequence divergence between the masked and pygmy shrews is estimated to be 15%-20%/Myr, the highest rate observed in D-loops of mammals. Rapid sequence evolution in shrews may be due either to their high metabolic rate and short generation time or to the presence of variable numbers of tandem repeats.      

Coastal intrusion of copepods: mechanisms and consequences on the population biology of Rhincalanus nasutus

In contrast to its usual habitat as a copepod that may occurin shelf or slope waters with low oxygen content between depthsfrom the surface to >2000 m, Rhincalanus nasutus was foundin a shallow (<60 m) embayment, the Arauco Gulf in Chile.Here, we document the complex life history of this copepod wheredid and ontogenetic vertical migratory behavior was co-ordinatedwith the circulation pattern which helped to retain a summerresident population in the vicinity of the gulf. With the onsetof the upwelling season in the southern summer, the mid-depthEquatorial Sub Surface Waters intrude into the gulf, leadingto the formation of a strong thermocline at 10–20 m andthe development of a two-layer circulation pattern. CopepoditesI, C.II and C.III (first stage to exhibit migratory behavior)were found within the gulf in the layer where the net transportwas at a minimum while chlorophyll-a concentrations were ata maximum. Older stages (C.IV-C.VI females and males) migratefrom their daytime depth in the bottom, shoreward-moving, low-oxygenlayer, to their night-time depth in the shallow seaward-movinglayer. The population of copepods retained in the area thuslyreproduce, as reflected in the sequential pulses of differentdevelopmental stages. Because coastal intrusions such as thisof R.nasutus have been documented for several other speciesduring the seasons of maximum phytoplankton production (upwelling),they may form part of a more widespread reproductive strategyof the larger zooplankton of coastal upwelling systems thanpreviously suspected.     

大鼠胼胝体内神经肽Y免疫反应阳性纤维的发育

本实验用免疫组织化学ＡＢＣ法研究了大鼠胼胝体内神经肽Ｙ免疫反应阳性（ＮＰＹ－ＩＲ）纤维的生后发育。结果发现,许多ＮＰＹ－ＩＲ纤维在大鼠出生时便存在于胼胝体内。ＮＰＹ－ＩＲ胼胝体纤维的密度在生后１周内继续逐渐增高,在第２周内达到最高峰。之后,ＮＰＹ－ＩＲ胼胝体纤维的密度逐渐下降,至第３周末时接近成年时的水平,即仅有少量ＮＰＹ－ＩＲ纤维存在于胼胝体内。这些结果提示在大鼠早期生后发育过程中许多ＮＰＹ－ＩＲ胼胝体纤维是暂时性的,其作用可能与大脑皮质的机能发育有关。     

Modulation of the affinity of the vasopressin receptor by magnesium ions.

The binding of [3H]vasopressin (AVP) and the 125I-labelled vasopressin antagonist (VP-AT) d(CH2)5[Tyr2(Me),Tyr9(NH2)]AVP to rat liver membranes was examined with or without the addition of milimolar concentrations of divalent cations. The binding of vasopressin was enhanced by Mg2+ and Co2+ and markedly decreased by EGTA. The addition of EGTA and Mg2+ together restored the binding to a value similar to that of Mg2+ alone. On the contrary, the addition of Mg2+, Co2+, EGTA, and the combination of EGTA and Mg2+ decreased the binding of VP-AT to rat liver membranes. Kinetic analyses showed that Mg2+ increased the Kd twofold for VP-AT; that is from 0.13 nM to 0.28 nM. Moreover, it showed that the receptor with or without the addition of Mg2+ consists of a single population of binding sites, indicating that the receptor is switched from a high affinity to a low affinity state for VP-AT in the presence of 10 mM Mg2+. GTP gamma S was unable to block the effect of Mg2+ on the binding of VP-AT. These results suggest that this divalent cation interacts with receptor itself producing a conformational changes which thus modulates the affinity of the receptor.     

VCAM-1 as a predictor biomarker in cardiovascular disease

The vascular cellular adhesion molecule-1 (VCAM-1) is a protein that canonically participates in the adhesion and transmigration of leukocytes to the interstitium during inflammation. VCAM-1 expression, together with soluble VCAM-1 (sVCAM-1) induced by the shedding of VCAM-1 by metalloproteinases, have been proposed as biomarkers in immunological diseases, cancer, autoimmune myocarditis, and as predictors of mortality and morbidity in patients with chronic heart failure (HF), endothelial injury in patients with coronary artery disease, and arrhythmias. This revision aims to discuss the role of sVCAM-1 as a biomarker to predict the occurrence, development, and preservation of cardiovascular disease.