Nickel tolerance and accumulation by bacteria from rhizosphere of nickel hyperaccumulators in serpentine soil ecosystem of Andaman, India

Rhizosphere microorganisms harboring nickel hyperaccumulators, Rinorea bengalensis (Wall.) O. K. and Dichapetalum gelonioides ssp. andamanicum (King) Leenh. endemic to serpentine outcrops of Andaman Islands, India, were screened for their tolerance and accumulation of Ni. The rhizosphere soils from both the plants were rich in total and available Ni along with Co, Cr, Fe and Mg but poor in microbial density and were dominated by bacteria. Out of total 123 rhizosphere microorganisms (99 bacteria and 24 fungi), bacteria were more tolerant to Ni than fungi. Viable cells of selected Ni-tolerant bacterial isolates (MIC = 13.6–28.9 mM Ni) belonging to Pseudomonas, Bacillus and Cupriavidus were capable of accumulating nickel (209.5–224.0 μM Ni g⁻¹ protein) from aqueous solution. Cupriavidus pauculus KPS 201 (MTCC 6280), showing highest degree of nickel tolerance (MIC 28.9 mM Ni) and uptake (224.0 μM Ni g⁻¹ protein, 60 min) was used for detailed study. Kinetics of nickel uptake in C. pauculus KPS 201 followed a linearized Lineweaver-Burk plot. The K _m and V _max for nickel uptake by minimal medium grown-cells approximated 1.5 mM Ni and 636.9 μM Ni g⁻¹ protein, respectively. The uptake process was inhibited by Co, Cu, Cd, Mg, Mn and Zn, however, complete inhibition was not achieved even in presence of 500 mM Mg. Metabolic inhibitors, sodium azide (1.0 mM) and carbonyl cyanide m-chlorophenylhydrazone (0.4 mM) strongly inhibited nickel uptake suggesting the process as an energy dependent one. The present study clearly shows that bacteria in the rhizosphere of Ni-hyperaccumulators are capable of tolerating high concentration of Ni and also possesses nickel uptake potential. The Ni-hyperaccumulators in combination with these Ni-resistant bacteria could be an ideal tool for nickel bioremediation.     

Isolation of Beauveria species from Lebanon and evaluation of its efficacy against the cedar web-spinning sawfly, Cephalcia tannourinensis

Larvae of the cedar web-spinning sawfly, Cephalcia tannourinensis Chevin (Hymenoptera: Pamphiliidae), infected with a white fungus were collected from the Tannourine-Hadath El-Jebbeh cedar forest. Macro- and micro-morphological data based on the examination of colonies, conidiophores, and conidial shape of the fungus suggested a Beauveria species. Sequence analysis of the internal transcribed spacer regions of the isolated fungus showed that it is most closely related to isolates of B. bassiana Clade C. The present study showed that the isolated B. bassiana is a naturally occurring entomopathogenic fungus parasitizing the larvae of C. tannourinensis in Lebanon. Laboratory bioassays showed that B. bassiana caused high mortality of eggs and larvae. The infected eggs turned brownish in color, while larvae of the first instar ceased feeding and showed immobility and rigidity within 5 days and before sporulating conidial mat appeared on their cuticle. Second and third larval instars took longer time to show fungal sporulation: mortalities ranged between 85 and 100% within 7 days when treated with different conidial concentrations. The efficacy of control of C. tannourinensis using B. bassiana was higher or equal to the reference insect growth regulator, diflubenzuron, suggesting the possibility of its success as a biological control agent.     

Neuroprotective effect of N-acetyl-aspartyl-glutamate in combination with mild hypothermia in the endothelin-1 rat model of focal cerebral ischaemia

Previously we showed that treatment with mild hypothermia (34 degrees C for 2 h) after a focal cerebral infarct was neuroprotective by reducing apoptosis in the penumbra (cortex), but not in the core (striatum) of the infarct. In this study we examined whether administration of N-acetyl-aspartyl-glutamate (NAAG) in combination with mild hypothermia could improve striatal neuroprotection in the endothelin-1 rat model. NAAG (10 mg/kg i.p.) was injected under normothermic (37 degrees C) or mild hypothermic conditions, either 40 min before or 20 min after the insult. NAAG reduced caspase 3 immunoreactivity in the striatum, irrespective of the time of administration and brain temperature. This neuroprotective effect could be explained, at least partially, by decreased nitric oxide synthase activity in the striatum and was blocked by the group II metabotropic glutamate receptor antagonist, LY341495. Hypothermia applied together with NAAG reduced both cortical and striatal caspase 3 immunoreactivity, as well as the overall ischaemic damage in these areas. However, no pronounced improvement was seen in total damaged brain volume. Extracellular glutamate levels did not correlate with the observed protection, whatever treatment protocol was applied. We conclude that treatment with NAAG causes the same degree of neuroprotection as treatment with hypothermia. Combination of the two treatments, although reducing apoptosis, does not considerably improve ischaemic damage.     

Costs of Illness Due to Cholera, Costs of Immunization and Cost-Effectiveness of an Oral Cholera Mass Vaccination Campaign in Zanzibar

Background

The World Health Organization (WHO) recommends oral cholera vaccines (OCVs) as a supplementary tool to conventional prevention of cholera. Dukoral, a killed whole-cell two-dose OCV, was used in a mass vaccination campaign in 2009 in Zanzibar. Public and private costs of illness (COI) due to endemic cholera and costs of the mass vaccination campaign were estimated to assess the cost-effectiveness of OCV for this particular campaign from both the health care provider and the societal perspective.

Methodology/Principal Findings

Public and private COI were obtained from interviews with local experts, with patients from three outbreaks and from reports and record review. Cost data for the vaccination campaign were collected based on actual expenditure and planned budget data. A static cohort of 50,000 individuals was examined, including herd protection. Primary outcome measures were incremental cost-effectiveness ratios (ICER) per death, per case and per disability-adjusted life-year (DALY) averted. One-way sensitivity and threshold analyses were conducted. The ICER was evaluated with regard to WHO criteria for cost-effectiveness. Base-case ICERs were USD 750,000 per death averted, USD 6,000 per case averted and USD 30,000 per DALY averted, without differences between the health care provider and the societal perspective. Threshold analyses using Shanchol and assuming high incidence and case-fatality rate indicated that the purchase price per course would have to be as low as USD 1.2 to render the mass vaccination campaign cost-effective from a health care provider perspective (societal perspective: USD 1.3).

Conclusions/Significance

Based on empirical and site-specific cost and effectiveness data from Zanzibar, the 2009 mass vaccination campaign was cost-ineffective mainly due to the relatively high OCV purchase price and a relatively low incidence. However, mass vaccination campaigns in Zanzibar to control endemic cholera may meet criteria for cost-effectiveness under certain circumstances, especially in high-incidence areas and at OCV prices below USD 1.3.     

Short- and Long-Term Alterations of Gene Expression in Limbic Structures by Repeated Electroconvulsive-Induced Seizures

Rats were submitted to a series of 10 daily electroconvulsive shocks (ECS). A first group of animals was killed 1 day after the last seizure and a second group 30 days later. Tyrosine hydroxylase (TH) activity was measured using an in vitro assay in the nucleus caudatus, anterior cortex, amygdala, substantia nigra, ventral tegmental area, and locus ceruleus. The mRNA corresponding to this enzyme (TH-mRNA) was evaluated using a cDNA probe at the cellular level in the ventral tegmental area, substantia nigra, and locus ceruleus. Met-enkephalin (MET)-immunoreactivity and the mRNA coding for the preproenkephalin (PPE-mRNA) were assayed in striatum and the central nucleus of the amygdala. The day after the last ECS an increase of TH activity was observed in the ventral tegmental area, locus ceruleus, and substantia nigra in parallel with a similar increase in the amygdala and striatum; in the anterior cortex TH activity remained unchanged. TH-mRNA was increased in the locus ceruleus, evidencing the presence in this structure of a genomic activation. The amounts of MET and PPE-mRNA were unaffected in the striatum but increased in the amygdala. Thirty days after the last ECS we observed a decrease of TH activity in the amygdala and of TH-mRNA amount in the ventral tegmental area. In the locus ceruleus TH-mRNA remained higher in treated animals than in controls whereas TH activity returned to control levels. These results demonstrate that a series of ECS induces an initial increase of the activity of mesoamygdaloid catecholaminergic neurons followed by a sustained decrease through alterations of TH gene expression which could mediate the clinical effect of the treatment.     

Capacités reproductrices et descendance de poulets ayant subi un transfert de cellules germinales primordiales durant la vie embryonnaire

Résumé Des cellules germinales primordiales de Dindon, transférées par injection intravasculaire à des embryons de Poulet préalablement stérilisés, peuvent subir une maturation complète dans les gonades de l'hôte et fournir des gamètes plus ou moins aptes à la fécondation.Les spermatozoïdes résultants ont fécondé des oeufs de poule avec une fréquence plus grande que les spermatozoïdes normaux de Dindon, mais sans permettre un développement embryonnaire plus important ou plus normal. Cependant, on n'est pas parvenu à leur faire féconder des oeufs de dinde.Les ufs résultants ont montré parfois un vitellus anormal et n'ont été pondus que durant 7 mois. Mis en présence de spermatozoïdes de coq, ils ont été quelquefois fécondés (ou peutêtre simplement activés), mais ils n'ont jamais fourni d'embryons. Fécondés par des spermatozoïdes de Dindon, ils ont fourni des embryons, parfois anormaux, qui ont atteint dans le meilleur cas le 15è jour d'incubation (stade 38 HH). Certainespraepennae de l'embryon qui a atteint ce stade montraient une pigmentation rouge brun qui ne peut pas être déterminée par le génotype du zygote (celui d'un Dindon de race blanche) et qui rappelle le phénotype de la mère nourricière (une poule rouge brun).A la suite de transferts intraspécifiques de cellules germinales primordiales, on a pu obtenir la maturation d'ovocytes de Rhode Island Red à l'intérieur d'un ovaire de Wyandotte Blanche (chez deux poules) et vice versa (chez une poule). La ponte a également été possible, mais à une fréquence souvent inférieure à la normale.Lorsqu'une poule Wyandotte Blanche, portant des ovocytes de Rhode Island Red a été accouplée à un coq Rhode Island Red normal, le duvet de leurs descendants s'est montré plus clair que celui des poussins Rhode Island Red dans un cas, mais il a été remplacé ensuite par un plumage rouge brun conforme au génotype.Lorsqu'une poule Rhode Island Red, portant des ovocytes de Wyandotte Blanche a été accouplée à un coq Wyandotte Blanche normal, le duvet de leurs descendants n'a jamais été conforme au génotype. Il présentait toujours du pigment noir plus ou moins étendu et, dans un cas, du pigment rouge brun, qui sont tous deux présents chez la mère nourricière. On ne connaît ni l'origine ni le mécanisme d'un tel transfert de pigments, qui ne représente peut-être qu'un effet transitoire affectant le duvet de la première génération. La crête, quant à elle, s'est toujours montrée conforme au génotype d'origine.

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Reproductive capacity and offspring of chickens submitted to a transfer of primordial germ cells during embryonic life

Summary Turkey primordial germ cells transfered by intravascular injection to previously sterilized chick embryos can undergo complete maturation inside the host's gonads and can give rise to gametes which are more or less suitable for fertilization.The resulting spermatozoa fertilized hen eggs at a higher frequency than normal turkey spermatozoa, but without allowing a longer or a more normal development. However, it was impossible to fertilize turkey eggs with them.The resulting eggs sometimes had an abnormal-looking yolk and were laid during the first 7 months only. Brought in contact with chicken spermatozoa, they were fertilized (or perhaps merely activated), but they never gave rise to embryos. Fertilized by turkey spermatozoa, they developed into embryos, sometimes abnormal, which in the best case reached the 15th day of incubation (stage 38 HH). Somepraepennae of the latter embryo showed a red-brown pigment which cannot be determined by the genotype of the zygote (a white turkey's) and which resembled the phenotype of the foster mother (a red-brown hen).After intraspecific transfer of primordial germ cells, maturation of Rhode Island Red oöcytes inside a Wyandotte White ovary (in two hens) and vice versa (in one hen) was achieved. Laying was also possible but often at a lower frequency than normal.When a Wyandotte White hen bearing Rhode Island Red oöcytes was mated with a normal Rhode Island cock, the down of their offspring looked brighter than Rhode Island Red chicken's in one case, but it was subsequently replaced by red-brown feathers according to the genotype.When a Rhode Island Red hen bearing Wyandotte White oöcytes was mated with a normal Wyandotte White cock, the down of their offspring was never in agreement with the genotype. It always showed a black pigment over more or less large areas and, in one case, a red-brown pigment, both of which were present in the foster mother. The origin and the mechanism of such a transfer of pigments are not understood. It might represent merely a temporary effect acting upon the down of the first generation. As far as the comb is concerned, it was always in agreement with the original genotype.

     

Identification of reaction networks for bioprocesses: determination of a partially unknown pseudo-stoichiometric matrix

In this paper we propose a methodology to determine the structure of the pseudo-stoichiometric coefficient matrix K in a mass balance-based model and to identify its coefficients from a set of available data. The first stage consists in estimating the number of reactions that must be taken into account to represent the main mass transfer within the bioreactor. This provides the dimension of K. Then we propose a method to directly determine the structure of the matrix (i.e. mainly its zeros and the signs of its coefficients). These methods are illustrated with simulations of a process of lipase production from olive oil by Candida rugosa.     

Inter-population variability of leaf morpho-anatomical and terpenoid patterns of Pistacia atlantica Desf. ssp. atlantica growing along an aridity gradient in Algeria

Three Algerian populations of female Pistacia atlantica shrubs were investigated in order to check whether their terpenoid contents and morpho-anatomical parameters may characterize the infraspecific variability. The populations were sampled along a gradient of increasing aridity from the Atlas mountains into the northwestern Central Sahara.As evidenced by Scanning Electron Microscopy, tufted hairs could be found only on seedling leaves from the low aridity site as a population-specific trait preserved also in culture. Under common garden cultivation seedlings of the high aridity site showed a three times higher density of glandular trichomes compared to the low aridity site. Increased aridity resulted also in reduction of leaf sizes while their thickness increased. Palisade parenchyma thickness also increases with aridity, being the best variable that discriminates the three populations of P. atlantica.Analysis of terpenoids from the leaves carried out by GC-MS reveals the presence of 65 compounds. The major compounds identified were spathulenol (23 μg g⁻¹ dw), α-pinene (10 μg g⁻¹ dw), verbenone (7 μg g⁻¹ dw) and β-pinene (6 μg g⁻¹ dw) in leaves from the low aridity site; spathulenol (73 μg g⁻¹ dw), α-pinene (25 μg g⁻¹ dw), β-pinene (18 μg g⁻¹ dw) and γ-amorphene (16 μg g⁻¹ dw) in those from medium aridity and spathulenol (114 μg g⁻¹ dw), α-pinene (49 μg g⁻¹ dw), germacrene D (29 μg g⁻¹ dw) and camphene (23 μg g⁻¹ dw) in leaves from the high aridity site. Terpene concentrations increased with the degree of aridity: the highest mean concentration of monoterpenes (136 μg g⁻¹ dw), sesquiterpenes (290 μg g⁻¹ dw) and total terpenes (427 μg g⁻¹ dw) were observed in the highest arid site and are, respectively, 3-, 5- and 4-fold higher compared to the lower arid site. Spathulenol and α-pinene can be taken as chemical markers of aridity. Drought discriminating compounds in low, but detectable concentrations are δ-cadinene and β-copaene. The functional roles of the terpenoids found in P. atlantica leaves and principles of their biosynthesis are discussed with emphasis on the mechanisms of plant resistance to drought conditions.