Recognition of pathogenic Yersinia enterocolitica by crystal violet binding and polymerase chain reaction

Cefsulodin-Irgasan-Novobiocin (CIN) agar is used for the selective isolation and enumeration of Yersinia enterocolitica from clinical specimens and food. The medium contains crystal violet and about 1 mmol l^-1 calcium and can be used for the phenotypic characterization of strains that carry a virulence plasmid. At 32°C, irrespective of pathogenicity, colonies are translucent with a pale pink centre surrounded by a transparent border ('bullseye'), while at 37°C pathogenic strains grow as calcium-dependent microcolonies which, because of crystal violet binding, are intensely coloured. These results were confirmed by the polymerase chain reaction with primers directed at the vir F gene, which is present only in pathogenic strains of Y. enterocolitica. Pathogenic strains of Y. enterocolitica can be recognized by growth at 37°C on Yersinia selective agar.     

Purification,Characterization, and Submitochondrial Localization of a 58-Kilodalton NAD(P)H Dehydrogenase

An NADH dehydrogenase activity from red beet (Beta vulgaris L.) root mitochondria was purified to a 58-kD protein doublet. An immunologically related dehydrogenase was partially purified from maize (Zea mays L. B73) mitochondria to a 58-kD protein doublet, a 45-kD protein, and a few other less prevalent proteins. Polyclonal antibodies prepared against the 58-kD protein of red beet roots were found to immunoprecipitate the NAD(P)H dehydrogenase activity. The antibodies cross-reacted to similar proteins in mitochondria from a number of plant species but not to rat liver mitochondrial proteins. The polyclonal antibodies were used in conjunction with maize mitochondrial fractionation to show that the 58-kD protein was likely part of a protein complex loosely associated with the membrane fraction. A membrane-impermeable protein cross-linking agent was used to further show that the majority of the 58-kD protein was located on the outer surface of the inner mitochondrial membrane or in the intermembrane space. Analysis of the cross-linked 58-kD NAD(P)H dehydrogenase indicated that specific proteins of 64, 48, and 45 kD were cross-linked to the 58-kD protein doublet. The NAD(P)H dehydrogenase activity was not affected by ethyleneglycol-bis([beta]-aminoethyl ether)-N,N[prime] -tetraacetic acid or CaCl2, was stimulated somewhat (21%) by flavin mononucleotide, was inhibited by p-chloromercuribenzoic acid (49%) and mersalyl (40%), and was inhibited by a bud scale extract of Platanus occidentalis L. containing platanetin (61%).     

Volume regulation by flounder red blood cells in anisotonic media

The nucleated high K, low Na red blood cells of the winter flounder demonstrated a volume regulatory response subsequent to osmotic swelling or shrinkage. During volume regulation the net water flow was secondary to net inorganic cation flux. Volume regulation the net water flow was secondary to net inorganic cation flux. Volume regulation after osmotic swelling is referred to as regulatory volume decrease (RVD) and was characterized by net K and water loss. Since the electrochemical gradient for K is directed out of the cell there is no need to invoke active processes to explain RVD. When osmotically shrunken, the flounder erythrocyte demonstrated a regulatory volume increase (RVI) back toward control cell volume. The water movements characteristic of RVI were a consequence of net cellular NaCl and KCl uptake with Na accounting for 75 percent of the increase in intracellular cation content. Since the Na electrochemical gradient is directed into the cell, net Na uptake was the result of Na flux via dissipative pathways. The addition of 10(-4)M ouabain to suspensions of flounder erythrocytes was without effect upon net water movements during volume regulation. The presence of ouabain did however lead to a decreased ration of intracellular K:Na. Analysis of net Na and K fluxes in the presence and absence of ouabain led to the conclusion that Na and K fluxes via both conservative and dissipative pathways are increased in response to osmotic swelling or shrinkage. In addition, the Na and K flux rate through both pump and leak pathways decreased in a parallel fashion as cell volume was regulated. Taken as a whole, the Na and K movements through the flounder erythrocyte membrane demonstrated a functional dependence during volume regulation.     

Biodeterioration of Mayan buildings at uxmal and tulum,Mexico

Uxmal and Tulum are two important Mayan sites in the Yucatan peninsula. The buildings are mainly composed of limestone and grey/black discoloration is seen on exposed walls and copious greenish biofilms on inner walls. The principal microorganisms detected on interior walls at both Uxmal and Tulum were cyanobacteria; heterotrophic bacteria and filamentous fungi were also present. A dark‐pigmented mitosporic fungus and Bacillus cereus, both isolated from Uxmal, were shown to be acidogenic in laboratory cultures. Cyanobacteria belonging to rock‐degrading genera Synechocystis and Gloeocapsa were identified at both sites. Surface analysis previously showed that calcium ions were present in the biofilms on buildings at Uxmal and Tulum, suggesting the deposition of biosolubilized stone. Apart from their potential to degrade the substrate, the coccoid cyanobacteria supply organic nutrients for bacteria and fungi, which can produce organic acids, further increasing stone degradation.     

Generation of marker-free transgenic maize by regular two-border <Emphasis Type="Italic">Agrobacterium</Emphasis> transformation vectors

By introducing additional T-DNA borders into a binary plasmid used in Agrobacterium-mediated plant transformation, previous studies have demonstrated that the marker gene and the gene of interest (GOI) can be carried by independent T-strands, which sometimes integrate in unlinked loci in the plant genome. This allows the recovery of marker-free transgenic plants through genetic segregation in the next generation. In this study, we have found that by repositioning the selectable marker gene in the backbone and leaving only the GOI in the T-DNA region, a regular two-border binary plasmid was able to generate marker-free transgenic maize plants more efficiently than a conventional single binary plasmid with multiple T-DNA borders. These results also provide evidence that both the right and left borders can initiate and terminate T-strands. Such non-canonical initiation and termination of T-strands may be the basis for the elevated frequencies of cotransformation and unlinked insertions.     

Accelerated hand bone mineral density loss is associated with progressive joint damage in hands and feet in recent-onset rheumatoid arthritis

Introduction

To investigate whether accelerated hand bone mineral density (BMD) loss is associated with progressive joint damage in hands and feet in the first year of rheumatoid arthritis (RA) and whether it is an independent predictor of subsequent progressive total joint damage after 4 years.

Methods

In 256 recent-onset RA patients, baseline and 1-year hand BMD was measured in metacarpals 2-4 by digital X-ray radiogrammetry. Joint damage in hands and feet were scored in random order according to the Sharp-van der Heijde method at baseline and yearly up to 4 years.

Results

68% of the patients had accelerated hand BMD loss (>-0.003 g/cm²) in the first year of RA. Hand BMD loss was associated with progressive joint damage after 1 year both in hands and feet with odds ratios (OR) (95% confidence intervals [CI]) of 5.3 (1.3-20.9) and 3.1 (1.0-9.7). In univariate analysis, hand BMD loss in the first year was a predictor of subsequent progressive total joint damage after 4 years with an OR (95% CI) of 3.1 (1.3-7.6). Multivariate analysis showed that only progressive joint damage in the first year and anti-citrullinated protein antibody positivity were independent predictors of long-term progressive joint damage.

Conclusions

In the first year of RA, accelerated hand BMD loss is associated with progressive joint damage in both hands and feet. Hand BMD loss in the first year of recent-onset RA predicts subsequent progressive total joint damage, however not independent of progressive joint damage in the first year.     

An overview of malaria transmission from the perspective of Amazon Anopheles vectors

In the Americas, areas with a high risk of malaria transmission are mainly located in the Amazon Forest, which extends across nine countries. One keystone step to understanding the Plasmodium life cycle in Anopheles species from the Amazon Region is to obtain experimentally infected mosquito vectors. Several attempts to colonise Ano- pheles species have been conducted, but with only short-lived success or no success at all. In this review, we review the literature on malaria transmission from the perspective of its Amazon vectors. Currently, it is possible to develop experimental Plasmodium vivax infection of the colonised and field-captured vectors in laboratories located close to Amazonian endemic areas. We are also reviewing studies related to the immune response to P. vivax infection of Anopheles aquasalis, a coastal mosquito species. Finally, we discuss the importance of the modulation of Plasmodium infection by the vector microbiota and also consider the anopheline genomes. The establishment of experimental mosquito infections with Plasmodium falciparum, Plasmodium yoelii and Plasmodium berghei parasites that could provide interesting models for studying malaria in the Amazonian scenario is important. Understanding the molecular mechanisms involved in the development of the parasites in New World vectors is crucial in order to better determine the interaction process and vectorial competence.     

Eukaryote-to-eukaryote gene transfer gives rise to genome mosaicism in euglenids

Background  

Euglenophytes are a group of photosynthetic flagellates possessing a plastid derived from a green algal endosymbiont, which was incorporated into an ancestral host cell via secondary endosymbiosis. However, the impact of endosymbiosis on the euglenophyte nuclear genome is not fully understood due to its complex nature as a 'hybrid' of a non-photosynthetic host cell and a secondary endosymbiont.