Lactic acid bacteria in Hamei and Marcha of North East India

Hamei and Marcha are mixed dough inocula used as starters for preparation of various indigenous alcoholic beverages in Manipur and Sikkim in India, respectively. These starters are traditionally prepared from rice with wild herbs and spices. Samples of Hamei and Marcha, collected from Manipur and Sikkim, respectively, were analysed for lactic acid bacterial composition. The population of lactic acid bacteria (LAB) was 6.9 and 7.1 Log cfu/g in Hamei and Marcha, respectively. On the basis of phenotypic and genotypic characters, LAB strains isolated from Hamei and Marcha were identified as Pediococcus pentosaceus, Lactobacillus plantarum and Lactobacillus brevis. Technological properties of LAB such as antimicrobial properties, effect on acidification, ability to produce biogenic amines and ethanol, degree of hydrophobicity and enzymatic activities were also performed. Pediococcus pentosaceus HS: B1, isolated from Hamei, was found to produce bacteriocin. None of the strains produced biogenic amines. LAB strains showed a strong acidifying ability and they also produced a wide spectrum of enzymes.     

The extra domain A from fibronectin targets antigens to TLR4-expressing cells and induces cytotoxic T cell responses in vivo

Vaccination strategies based on the in vivo targeting of Ags to dendritic cells (DCs) are needed to improve the induction of specific T cell immunity against tumors and infectious agents. In this study, we have used a recombinant protein encompassing the extra domain A from fibronectin (EDA), an endogenous ligand for TLR4, to deliver Ags to TLR4-expressing DC. The purified EDA protein was shown to bind to TLR4-expressing HEK293 cells and to activate the TLR4 signaling pathway. EDA also stimulated the production by DC of proinflammatory cytokines such as IL-12 or TNF-alpha and induced their maturation in vitro and in vivo. A fusion protein between EDA and a cytotoxic T cell epitope from OVA efficiently presented this epitope to specific T cells and induced the in vivo activation of a strong and specific CTL response. Moreover, a fusion protein containing EDA and the full OVA also improved OVA presentation by DC and induced CTL responses in vivo. These EDA recombinant proteins protected mice from a challenge with tumor cells expressing OVA. These results strongly suggest that the fibronectin extra domain A may serve as a suitable Ag carrier for the development of antiviral or antitumoral vaccines.     

Factors influencing the seasonal life history of the pitcher-plant mosquito, Wyeomyia smithii

Abstract.  1. The effects of resource levels, thermal microclimate, and seasonal oviposition patterns on fecundity and survivorship in the pitcher-plant mosquito, Wyeomyia smithii (Coq.), were examined at a northern Wisconsin bog over the course of 2 years. Wyeomyia smithii are bivoltine at this locality, thereby enabling the study of summer and overwintering generations separately.
2. Nutrient resources of W. smithii were not limiting and there was no indication of density-dependent survivorship or fecundity.
3. Oviposition rates were highest in young, large pitchers and individual mosquitoes appeared to allocate only a few eggs to any one leaf.
4. Winter was the harsh season, and the principal manifestation of seasonal harshness was reduced survivorship.
5. Overwintering W. smithii that had been oviposited later in the summer had a higher odds of survival than those oviposited earlier in the summer.
6. It was concluded that dispersal of eggs among many pitchers serves to spread the risk of encountering lethal winter temperatures among spatially unpredictable patches.     

Comparative assessment of fermentation techniques useful in the processing of ogi

Ogiis processed traditionally by the use of uncontrolled spontaneous fermentation of maize, sorghum and millet. In this study, traditionally applied spontaneous fermentation was compared with accelerated batch fermentation (or back-slopping) and the use of starter cultures to initiate fermentation. Lactic acid bacteria populations comprised 95 of the total viable bacteria and remained prominent throughout the fermentations, while number of moulds and coliform bacteria declined as the fermentation progressed. The fermentation method involving the application of starter culture helps most to control the prevalence of coliforms and moulds. Lactic acid bacteria, such as Lactococcus raffinolactis, Pediococcussp.,Pediococcus pentosaceus, Lactobacillus plantarum, Lb. suebicus and Lb. brevis,were isolated at different processing stages of ogi using accelerated batch fermentation (back-slopping) technique. Highest increase in acidity was observed immediately after wet-milling and sieving fermenting maize grains at 28 and 48 h. Sharp increases in the reducing sugar levels were noted between 24 and 28 h of fermentations during wet-milling and sieving processes.     

Single lamellar mechanics of the human lumbar anulus fibrosus

The mechanical behavior of the entire anulus fibrosus is determined essentially by the tensile properties of its lamellae, their fiber orientations, and the regional variation of these quantities. Corresponding data are rare in the literature. The paper deals with an in vitro study of single lamellar anulus lamellae and aims to determine (i) their tensile response and regional variation, and (ii) the orientation of lamellar collagen fibers and their regional variation. Fresh human body-disc-body units (L1–L2, n=11) from cadavers were cut midsagittally producing two hemidisc units. One hemidisc was used for the preparation of single lamellar anulus specimens for tensile testing, while the other one was used for the investigation of the lamellar fiber orientation. Single lamellar anulus specimens with adjacent bone fragments were isolated from four anatomical regions: superficial and deep lamellae (3.9±0.21 mm, mean ± SD, apart from the outer boundary surface of the anulus fibrosus) at ventro-lateral and dorsal positions. The specimens underwent cyclic uniaxial tensile tests at three different strain rates in 0.15 mol/l NaCl solution at 37°C, whereby the lamellar fiber direction was aligned with the load axis. For the characterization of the tensile behavior three moduli were calculated: E_low (0–0.1 MPa), E_medium (0.1–0.5 MPa) and E_high (0.5–1 MPa). Additionally, specimens were tested with the load axis transverse to the fiber direction. From the second hemidisc fiber angles with respect to the horizontal plane were determined photogrammetrically from images taken at six circumferential positions from ventral to dorsal and at three depth levels. Tensile moduli along the fiber direction were in the range of 28–78 MPa (regional mean values). Superficial lamellae have larger E_medium (p=0.017) and E_high (p=0.012) than internal lamellae, and the mean value of superficial lamellae is about three times higher than that of deep lamellae. Tensile moduli of ventro-lateral lamellae do not differ significantly from the tensile moduli of dorsal lamellae, and E_low is generally indifferent with respect to the anatomical region. Tensile moduli transverse to the fiber direction were about two orders of magnitude smaller (0.22±0.2 MPa, mean ± SD, n=5). Tensile properties are not correlated significantly with donor age. Only small viscoelastic effects were observed. The regional variation of lamellar fiber angle is described appropriately by a regression line ||=23.2+0.130× (r²=0.55, p<0.001), where is the polar angle associated with the circumferential position. The single anulus lamella may be seen as the elementary structural unit of the anulus fibrosus, and exhibits marked anisotropy and distinct regional variation of tensile properties and fiber angles. These features must be considered for appropriate physical and numerical modeling of the anulus fibrosus.     

A phenomenological model for atherosclerotic plaque growth and rupture

The objective of this communication is to develop a computer-based framework for the overall coupled phenomena leading to growth and rupture of atherosclerotic plaques. The modeling is purposely simplified to expose the dominant phenomenological controlling mechanisms, and their coupled interaction. The main ingredients of the present simplified modeling approach, describing the events that occur due to the presence and oxidation of excess low-density lipoprotein (LDL) in the intima, are: (i) adhesion of monocytes to the endothelial surface, which is controlled by the intensity of the blood flow and the adhesion molecules stimulated by the excess LDL, (ii) penetration of the monocytes into the intima and subsequent inflammation of the tissue, and (iii) rupture of the plaque accompanied with some degree of thrombus formation or even subsequent occlusive thrombosis. The set of resulting coupled equations, each modeling entirely different physical events, is solved using an iterative staggering scheme, which allows the equations to be solved in a computationally convenient decoupled fashion. Theoretical convergence properties of the scheme are given as a function of physical parameters involved. A numerical example is given to illustrate the modeling approach and an a priori prediction for time to rupture as a function of arterial geometry, diameter of the monocyte, adhesion stress, bulk modulus of the ruptured wall material, blood viscosity, flow rate and mass density of the monocytes.     

Random amplification of polymorphic DNA (RAPD) typing of carnobacteria isolated from hindgut chamber and large intestine of Atlantic cod (Gadus morhua l.)

Autochthonous and allochthonous bacteria were isolated from hindgut chamber and large intestine of fed and starved Atlantic cod (Gadus morhua L.). All bacterial strains isolated from hindgut chamber belong to carnobacteria. However, only 10.2% of the bacteria strains from the large intestine belong to carnobacteria. Random amplification of polymorphic DNA (RAPD) analysis using three selective primers, was performed to further identify the carnobacteria strains. Nine of these were isolated from hindgut chamber contents, ten associated with epithelial cells of the hindgut chamber, and six isolated from the large intestines of fed and starved fish. The 25 isolates segregated into eight clusters. The major cluster comprised nine strains isolated from the hindgut chamber of both fed and starved fish showing low similarity with the reference strains. The other strains isolated from the hindgut were located in clusters showing high similarity with Carnobacterium gallinarum or Carnobacterium piscicola. Strains isolated from large intestine appeared more divergent and were located in five different clusters. Autochthonous (indigenous) bacteria were clearly demonstrated in the hindgut chamber as transmission electron microscopy revealed rod-shaped bacteria between adjacent microvilli. Endocytosis of bacteria by epithelial cells was observed in the hindgut chamber.     

Properties of an LNA-modified ricin RNA aptamer

'Locked nucleic acids' (LNAs) are sugar modified nucleic acids containing the 2'-O-4'C-methylene-β-D-ribofuranoses. The substitution of RNAs with LNAs leads to an enhanced thermostability. Aptamers are nucleic acids, which are selected for specific target binding from a large library pool by the 'SELEX' method. Introduction of modified nucleic acids into aptamers can improve their stability. The stem region of a ricin A chain RNA aptamer was substituted by locked nucleic acids. Different constructs of the LNA-substituted aptamers were examined for their thermostability, binding activity, folding and RNase sensitivity as compared to the natural RNA counterpart. The LNA-modified aptamers were active in target binding, while the loop regions and the adjacent stem nucleotides remained unsubstituted. The thermostability and RNase resistance of LNA substituted aptamers were enhanced as compared to the native RNA aptamer. This study supports the approach to substitute the aptamer stem region by LNAs and to leave the loop region unmodified, which is responsible for ligand binding. Thus, LNAs possess an encouraging potential for the development of new stabilized nucleic acids and will promote future diagnostic and therapeutic applications.