Characterization of a novel vanadium-binding protein (VBP-129) from blood plasma of the vanadium-rich ascidian Ascidia sydneiensis samea

The ascidians, the so-called sea squirts, accumulate high levels of vanadium, a transition metal. Since Henze first observed this physiologically unusual phenomenon about one hundred years ago, it has attracted interdisciplinary attention from chemists, physiologists, and biochemists. The maximum concentration of vanadium in ascidians can reach 350 mM, and most of the vanadium ions are stored in the +3 oxidation state in the vacuoles of vanadium-accumulating blood cells known as vanadocytes. Many proteins involved in the accumulation and reduction of vanadium in the vanadocytes, blood plasma, and digestive tract have been identified. However, the process by which vanadium is taken in prior to its accumulation in vanadocytes has not been elucidated. In the present study, a novel vanadium-binding protein, designated VBP-129, was identified from blood plasma of the vanadium-rich ascidian Ascidia sydneiensis samea. Although VBP-129 mRNA was transcribed in all A. sydneiensis samea tissues examined, the VBP-129 protein was exclusively localized in blood plasma and muscle cells of this ascidian. It bound not only to VO(2+) but also to Fe(3+), Co(2+), Cu(2+), and Zn(2+); on the other hand, a truncated form of VBP-129, designated VBP-88, bound only to Co(2+), Cu(2+) and Zn(2+). In a pull-down assay, an interaction between VanabinP and VBP-129 occurred both in the presence and the absence of VO(2+). These results suggest that VBP-129 and VanabinP function cooperatively as metallochaperones in blood plasma.     

Incidence and clinical characteristics of group A rotavirus infections among children admitted to hospital in Kilifi, Kenya

Background

Rotavirus, predominantly of group A, is a major cause of severe diarrhoea worldwide, with the greatest burden falling on young children living in less-developed countries. Vaccines directed against this virus have shown promise in recent trials, and are undergoing effectiveness evaluation in sub-Saharan Africa. In this region limited childhood data are available on the incidence and clinical characteristics of severe group A rotavirus disease. Advocacy for vaccine intervention and interpretation of effectiveness following implementation will benefit from accurate base-line estimates of the incidence and severity of rotavirus paediatric admissions in relevant populations. The study objective was to accurately define the incidence and severity of group A rotavirus disease in a resource-poor setting necessary to make informed decisions on the need for vaccine prevention.

Methods and Findings

Between 2002 and 2004 we conducted prospective surveillance for group A rotavirus infection at Kilifi District Hospital in coastal Kenya. Children < 13 y of age were eligible as “cases” if admitted with diarrhoea, and “controls” if admitted without diarrhoea. We calculated the incidence of hospital admission with group A rotavirus using data from a demographic surveillance study of 220,000 people in Kilifi District. Of 15,347 childhood admissions 3,296 (22%) had diarrhoea, 2,039 were tested for group A rotavirus antigen and, of these, 588 (29%) were positive. 372 (63%) rotavirus-positive cases were infants. Of 620 controls 19 (3.1%, 95% confidence interval [CI] 1.9–4.7) were rotavirus positive. The annual incidence (per 100,000 children) of rotavirus-positive admissions was 1,431 (95% CI 1,275–1,600) in infants and 478 (437–521) in under-5-y-olds, and highest proximal to the hospital. Compared to children with rotavirus-negative diarrhoea, rotavirus-positive cases were less likely to have coexisting illnesses and more likely to have acidosis (46% versus 17%) and severe electrolyte imbalance except hyponatraemia. In-hospital case fatality was 2% among rotavirus-positive and 9% among rotavirus-negative children.

Conclusions

In Kilifi > 2% of children are admitted to hospital with group A rotavirus diarrhoea in the first 5 y of life. This translates into over 28,000 vaccine-preventable hospitalisations per year across Kenya, and is likely to be a considerable underestimate. Group A rotavirus diarrhoea is associated with acute life-threatening metabolic derangement in otherwise healthy children. Although mortality is low in this clinical research setting this may not be generally true in African hospitals lacking rapid and appropriate management.     

Design and synthesis of regioisomerically pure unsymmetrical xanthene derivatives for staining live cells and their photochemical properties

We have demonstrated the synthesis of regioisomerically pure unsymmetrical xanthene derivatives consisting of three units which can be independently modified to control their physical properties. The photochemical properties of the synthetic unsymmetrical xanthene derivatives were investigated in solution by UV–vis absorption and fluorescence measurements, and their cell imaging properties were examined by confocal laser-scanning microscopy.     

Effect of Exogenous Siderophores on Iron Uptake Activity of Marine Bacteria under Iron-Limited Conditions

More than 60% of species examined from a total of 421 strains of heterotrophic marine bacteria which were isolated from marine sponges and seawater were observed to have no detectable siderophore production even when Fe(III) was present in the culture medium at a concentration of 1.0 pM. The growth of one such non-siderophore-producing strain, alpha proteobacterium V0210, was stimulated under iron-limited conditions with the addition of an isolated exogenous siderophore, N,N′-bis (2,3-dihydroxybenzoyl)-O-serylserine from a Vibrio sp. Growth was also stimulated by the addition of three exogenous siderophore extracts from siderophore-producing bacteria. Radioisotope studies using ⁵⁹Fe showed that the iron uptake ability of V0210 increased only with the addition of exogenous siderophores. Biosynthesis of a hydroxamate siderophore by V0210 was shown by paper electrophoresis and chemical assays for the detection of hydroxamates and catechols. An 85-kDa iron-regulated outer membrane protein was induced only under iron-limited conditions in the presence of exogenous siderophores. This is the first report of bacterial iron uptake through an induced siderophore in response to exogenous siderophores. Our results suggest that siderophores are necessary signaling compounds for growth and for iron uptake by some non-siderophore-producing marine bacteria under iron-limited conditions.     

Herpesvirus saimiri Tip gene causes T-cell lymphomas in transgenic mice

New World primates develop T-cell lymphomas on infection with Herpesvirus saimiri. To investigate the oncogenic potential of the Tip gene of Herpesvirus saimiri strain C488, we tried to establish transgenic mice that should express Tip under control of a constitutive promoter. Although transgene-positive embryos were found, lines could not be established. However, using a system in which the transgene has to be activated by a Cre recombinase-mediated deletion, we were able to obtain several Tip transgenic lines. At high expression levels, the mice developed T-cell lymphomas. Thus, Tip can induce lymphomas and is therefore very likely responsible for the oncogenicity of Herpesvirus saimiri.     

Sarcocystis muris--a rare case in laboratory mice

In a lifespan transgeneration study under standard laboratory conditions using a total of 4682 CBA/J mice, unusual intramuscular inclusions were found in the diaphragm, heart and skeletal muscle of one mouse using light microscopy. Located within the myocytes, they caused no visible tissue reaction. Cross-sections of these spherical and cystic lesions showed numerous banana-shaped structures, identified as permanent parasitic bradyzoites, which permitted these infections to be diagnosed microscopically as sarcocystosis.     

Deficiency in mitochondrial aldehyde dehydrogenase increases the risk for late-onset Alzheimer's disease in the Japanese population

Mitochondrial aldehyde dehydrogenase 2 (ALDH2) deficiency is caused by a mutant allele in the Mongoloids. To examine whether genetic constitutions affecting aldehyde metabolism influence the risk for late-onset Alzheimer's disease (LOAD), we performed a case-control study in the Japanese population on the deficiency in ALDH2 caused by the dominant-negative mutant allele of the ALDH2 gene (ALDH2*2). In a comparison of 447 patients with sex, age, and region matched nondemented controls, the genotype frequency carrying the ALDH2*2 allele was significantly higher in the patients than in the controls (48.1% vs 37.4%, P = 0.001). Logistic regression analysis indicates that carriage of the ALDH2*2 allele is an independent risk for LOAD of the epsilon4 allele of the apolipoprotein E gene (APOE-epsilon4) (P = 0.002). Moreover, the odds ratio for LOAD in carriers of the ALDH2*2 allele was almost twice that in noncarriers, irrespective of status with regard to the APOE-epsilon4 allele. Among patients homozygous for the APOE-epsilon4 allele, age at onset of LOAD was significantly lower in those with than without the ALDH2*2 allele. In addition, dosage of the ALDH2*2 allele significantly affected age at onset of patients homozygous for the APOE-epsilon4 allele. These results indicate that the ALDH2 deficiency is a risk for LOAD, synergistically acting with the APOE-epsilon4 allele.     

Cryopreservation and orthotopic transplantation of rat ovaries as a means of gamete banking

Besides the exponentially increasing number of mouse strains, the rising number of rat strains, due to the establishment of transgenic and coisogenic strains in this species, surpasses the capacity of most animal houses. Cryopreservation of gametes may be a means of solving these problems. Here we describe an easy and fast method for the cryopreservation and transplantation of frozen-thawed ovaries of the rat. Ovaries of the rat inbred strain WKY/Ztm were frozen with dimethylsulphoxide as cryoprotectant and stored at -196 degrees C. Orthotopical transplantation was performed into ovariectomized syngenic recipients. Re-establishment of the reproductive cycle in the recipients was confirmed by vaginal cytology. The morphological integrity of frozen and unfrozen ovaries was compared by histological means after staining with haematoxylin and eosin. The number of litters and offspring was recorded. Reproductive cycle was re-established in all recipients of unfrozen ovaries and in more than 50% of recipients that received frozen-thawed ovaries. One-third of the former and more than 25% of the latter became pregnant and delivered at least one litter. Cyropreservation of ovaries can thus be considered as a reliable method of preserving scientifically and economically important mutant stock, as well as congenic rat strains that are currently not required.