The extracellular matrix of the cuticle of Gordius panigettensis (Gordioiidae,Nematomorpha): observations by TEM,SEM and AFM

The cuticle of Gordius panigettensis (Sciacchitano, 1955) was studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM). The cuticle is composed of 30-50 compact layers. The number of the layers is higher in the central part of the animal's body and decreases at the extremities. Each layer is composed of parallel tightly packed fibres approximately 640 nm in diameter and of indefinite length. The fibres run strictly parallel within each layer, while in adjoining layers they run at a variable angle from 45 degrees in the central body to 90 degrees in the extremities. Each fibre shows a barely detectable filamentous inner structure and is enveloped in a thin highly regular net formed by hexagonal meshes. Our results suggested that these fibres should be proteinaceous although non-collagenous. Thinner radial fibres run among the large fibres and across all the layers and span the whole thickness of the cuticle from the epithelial layer located deep underneath the large fibres up to the epicuticle on the external surface of the animal.     

Enhanced production and partial characterization of an extracellular polysaccharide from newly isolated Azotobacter sp. SSB81

A strain was selected by its highest extracellular polysaccharide (EPS) production ability compare to other isolates from the same rhizospheric soil. The selected strain was identified by 16S rDNA sequencing and designated as SSB81. Phylogenetic analysis of the gene sequence showed its close relatedness with Azotobacter vinelandii and Azotobacter salinestris. Maximum EPS (2.52 g l⁻¹) was recovered when the basal medium was supplemented with glucose (2.0%), riboflavin (1 mg l⁻¹) and casamino acid (0.2%). The EPS showed a stable viscosity level at acidic pH (3.0–6.5) and the pyrolysis temperature was found to be at 116.73 °C with an enthalpy (ΔH) of 1330.72 Jg⁻¹. MALDI TOF mass spectrometric result suggests that polymer contained Hex₅Pent₃ as oligomeric building subunit. SEM studies revealed that the polymer had a porous structure with small pore size distribution indicating the compactness of the polymer. This novel EPS may find possible application as a polymer for environmental bioremediation and biotechnological processes.     

An Extracellullar Nuclease from Bacillus Firmus VKPACU-1: Specificity and Mode of Action

An extracellular nuclease from Bacillus firmus VKPACU-1 was multifunctional enzyme, this nuclease hydrolyzed poly U rapidly and more preferentially than the other homopolyribonucleotides. Hydrolysis of RNA this enzyme released mononucleotides in the order 5′UMP > 5′AMP > 5′GMP where as in hydrolysis of DNA the mononucleotides in the order of 5′dAMP > 5′dGMP > 5′dTMP and oligonucleotides. Uridylic linkages in RNA and adenylic linkages in DNA were preferentially cleaved by the nuclease. Nuclease produced oligonucleotides having only 3’ hydroxyl and 5’ phosphate termini. Present nuclease hydrolyzed RNA and DNA released oligonucleotides as major end products and mononucleotides, suggesting an endo mode of action.     

Crosslinked elastic fibers are necessary for low energy loss in the ascending aorta

In the large arteries, it is believed that elastin provides the resistance to stretch at low pressure, while collagen provides the resistance to stretch at high pressure. It is also thought that elastin is responsible for the low energy loss observed with cyclic loading. These tenets are supported through experiments that alter component amounts through protease digestion, vessel remodeling, normal growth, or in different artery types. Genetic engineering provides the opportunity to revisit these tenets through the loss of expression of specific wall components. We used newborn mice lacking elastin (Eln^−/−) or two key proteins (lysyl oxidase, Lox^−/−, or fibulin-4, Fbln4^−/−) that are necessary for the assembly of mechanically-functional elastic fibers to investigate the contributions of elastic fibers to large artery mechanics. We determined component content and organization and quantified the nonlinear and viscoelastic mechanical behavior of Eln^−/−, Lox^−/−, and Fbln4^−/− ascending aorta and their respective controls. We confirmed that the lack of elastin, fibulin-4, or lysyl oxidase leads to absent or highly fragmented elastic fibers in the aortic wall and a 56–97% decrease in crosslinked elastin amounts. We found that the resistance to stretch at low pressure is decreased only in Eln^−/− aorta, confirming the role of elastin in the nonlinear mechanical behavior of the aortic wall. Dissipated energy with cyclic loading and unloading is increased 53–387% in Eln^−/−, Lox^−/−, and Fbln4^−/− aorta, indicating that not only elastin, but properly assembled and crosslinked elastic fibers, are necessary for low energy loss in the aorta.     

G protein-coupled, extracellular Ca2+ (Ca o 2+ )-sensing receptor enables Ca o 2+ to function as a versatile extracellular first messenger

The cloning of a G protein-coupled, extracellular Ca²⁺ (Ca _o ²⁺ )-sensing receptor (CaR) has afforded a molecular basis for a number of the known effects of Ca _o ²⁺ on tissues involved in maintaining systemic calcium homeostasis, especially parathyroid gland and kidney. In addition to providing molecular tools for showing that CaR messenger RNA and protein are present within these tissues, the cloned CaR has permitted documentation that several human diseases are the result of inactivating or activating mutations of this receptor as well as generation of mice that have targeted disruption of the CaR gene. Characteristic changes in the functions of parathyroid and kidney in these patients as well as in the CaR “knockout” mice have elucidated considerably the CaR’s physiological roles in mineral ion homeostasis. Nevertheless, a great deal remains to be learned about how this receptor regulates the functioning of other tissues involved in Ca _o ²⁺ metabolism, such as bone and intestine. Further study of these human diseases and of the mouse models will doubtless be useful in gaining additional understanding of the CaR’s roles in these latter tissues. Furthermore, we understand little of the CaR’s functions in tissues that are not directly involved in systemic mineral ion metabolism, where the receptor probably serves diverse other roles. Some of these functions may be related to the control of intra- and local extracellular concentrations of Ca²⁺, while others may be unrelated to either systemic or local ionic homeostasis. In any case, the CaR and conceivably additional receptors/sensors for Ca²⁺ or other extracellular ions represent versatile regulators of a wide variety of cellular functions and represent important targets for novel classes of therapeutics.     

A molecular analysis of matrix remodeling and angiogenesis during long bone development

The replacement of cartilage by bone is the net result of genetic programs that control chondrocyte differentiation, matrix degradation, and bone formation. Disruptions in the rate, timing, or duration of chondrocyte proliferation and differentiation result in shortened, misshapen skeletal elements. In the majority of these skeletal disruptions, vascular invasion of the elements is also perturbed. Our hypothesis is that the processes involved in endochondral ossification are synchronized via the vasculature. The purpose of this study was to examine carefully the events of vascular invasion and matrix degradation in the context of chondrocyte differentiation and bone formation. Here, we have produced a ‘molecular map’ of the initial vascularization of the developing skeleton that provides a framework in which to interpret a wide range of fetal skeletal malformations, disruptions, and dysplasias.     

Hierarchical patterns of paternity within crowns of Albizia julibrissin (Fabaceae)

The floral architecture and phenology of the tree species Albizia julibrissin (Fabaceae) offer the potential for flowers within inflorescences to share common pollen donors. Patterns of paternity within individual tree crowns may differ among isolated individuals and those in populations due to differences in pollinator foraging behavior. To determine how genetic diversity is partitioned within individual seed pools and whether these patterns differ among isolated and population trees, we obtained all fruits from three inflorescences from four clusters from three isolated trees and from three population trees in Athens, Georgia. We assayed 14 polymorphic allozymes to genotype all progeny within singly sired fruits to determine the multilocus genotype of each fruit's pollen donor. Inflorescences had multiple pollen donors, but simulation analyses revealed that redundancy of pollen donors tended to be more likely within inflorescences than randomly across the crown. Analysis of genetic and genotypic diversity indicated that individual maternal trees received pollen from many donors in uneven frequencies. Results suggest that isolated trees receive pollen from slightly fewer pollen donors and experience more within-plant pollinator movement than trees in populations. However, isolated trees receive qualitatively similar pollen from many sources, suggesting that these trees are not effectively isolated and that pollen moves long distances in this species.     

Cu(I)-thionein release from copper-loaded yeast cells

Summary The release of intact CU(I)₈-thionein from copper-resistant copper-loaded yeast cells, strain X 2180-1Aa, has been shown. This copper(I)-thiolate-rich protein was characterized and compared with the chemical and physicochemical properties of intracellular yeast Cu-thionein. The same molecular mass and stoichiometry of 8 mol copper atoms/mol protein was found. No detectable difference between the Cu-thioneins was seen in luminescence emission, electronic absorption in the ultraviolet region, chiroptical data or amino acid composition. The importance of stable Cu(I)-thiolates in Cu-thionein as a safe vehicle for transporting copper in a non-reactive manner is confirmed.     

Intracellular angiotensin II as a regulator of muscle tone in vascular resistance vessels. Pathophysiological implications

The influence of intracellular angiotensin II on the regulation of potassium current and membrane potential of smooth muscle cells of mesenteric arteries and its relevance for the regulation of vascular tone was reviewed. The presence of components of the renin angiotensin system (RAS) in different cells of the cardiovascular system, was discussed including their presence in the nuclei and mitochondria. Emphasis was given to the opposite effects of intracellular and extracellular angiotensin II (Ang II) on the regulation of potassium current, membrane potential and contractility of vascular resistance vessels and its implication to vascular physiology and pathology and the possible role of epigenetic factors on the expression of angiotensin II (Ang II) and renin in vascular resistance vessels as well as its possible pathophysiological role in hypertension and other cardiovascular diseases.     

Purification and Characterization of an Extracellular Low Temperature-Active and Alkaline Stable Peptidase from Psychrotrophic Acinetobacter sp. MN 12 MTCC (10786)

An extracellular low temperature-active alkaline stable peptidase from Acinetobacter sp. MN 12 was purified to homogeneity with a purification fold of 9.8. The enzyme exhibited specific activity of 6,540 U/mg protein, with an apparent molecular weight of 35 kDa. The purified enzyme was active over broad range of temperature from 4 to 60 °C with optimum activity at 40 °C. The enzyme retained more than 75 % of activity over a broad range of pH (7.0–11.0) with optimum activity at pH 9.0. The purified peptidase was strongly inhibited by phenylmethylsulfonyl fluoride, giving an indication of serine type. The K _m and V _max for casein and gelatin were 0.3529, 2.03 mg/ml and 294.11, 384.61 μg/ml/min respectively. The peptidase was compatible with surfactants, oxidizing agents and commercial detergents, and effectively removed dried blood stains on cotton fabrics at low temperature ranging from 15 to 35 °C.