Solar power enhancement of electrokinetic bioremediation of phenanthrene by Mycobacterium pallens

Enhanced bioremediation of phenanthrene-contaminated soil with Mycobacterium pallens was conducted. Kaolinite was used in the tests as a soil matrix and was artificially contaminated with phenanthrene at a concentration of 2 mg phenanthrene per gram dry soil. Mycobacterim pallens at concentration of 10⁸ colony-forming units (CFU) per milliliter was used as a potential microorganism to degrade phenanthrene. Aspects of the study included evaluating efficacy of using Mycobacterium pallens for degrading phenanthrene, electrokinetics for delivering nutrients and microorganisms to contaminated soil, and solar panels for generating power for electrokinetic bioremediation. A novel anode-cathode configuration, in which the anode and cathode are placed in the same compartment, was implemented to control/minimize changes in pH during electrokinetic bioremediation. The nutrients (NO₃^?), electrical current, temperature, Mycobacterium pallens (CFU), and phenatherene concentration were evaluated. The results showed that solar panels generated sufficient power for electrokinetic bioremediation. The highest current obtained was generated when bacteria and nutrients were added to the soil. This was associated with the highest phenanthrene removal from the soil (50% of the initial concentration). Additionally, we determined that the novel anode-cathode configuration in the electrokinetic bioremediation cell was successful in delivering the bacteria and nutrients to the contaminated soil and in maintaining a relatively neutral pH around the electrode compartments, which improved the remediation. Overall, this study showed that the use of solar power with electrokinetic bioremediation can provide a cost-effective approach to reduce and remove hydrocarbon contaminations in soil.     

Magnetic and structural studies of novel tetranickel hydroxamates

The dinickel(II) compound [Ni₂(μ-OAc)₂(OAc)₂(μ-H₂O)(asy·dmen)₂]·2.5H₂O, 1; undergoes facile reaction in a 1:2 molar ratio with benzohydroxamic acid (BHA) in ethanol to give the novel nickel(II) tetranuclear hydroxamate complex [Ni₄(μ-OAc)₃(μ-BA)₃(asy·dmen)₃][OTf]₂·H₂O, 2, in which the bridging acetates, bridging two nickel atoms in 1, undergo a carboxylate shift from the μ₂-η¹:η¹ bridging mode of binding to the μ₃-η¹:η² bridging three nickel atoms in the tetramer. The structure of complex 2 was determined by single-crystal X-ray crystallography. The two monodentate acetates, water and two bidentate bridging acetates of two moles of complex 1 are replaced by three monodentate bridging acetates and three benzohydroxamates. Three nickel atoms in the tetramer, Ni(2), Ni(3) and Ni(4) are in a N₂O₄ octahedral environment, while the fourth nickel atom Ni(1) is in an O(6) octahedral environment. The Ni-Ni separations are Ni(1)-Ni(2) = 3.108 Å, Ni(1)-Ni(3) = 3.104 Å and Ni(1)-Ni(4) = 3.110 Å, which are longer than previously studied in dinuclear urease inhibited models but shorter than in the nickel(II) tetrameric glutarohydroxamate complex [Ni₄(μ-OAc)₂(μ-gluA₂)₂(tmen)₄][OTf]₂, isolated and characterized previously in this laboratory. Magnetic studies of the tetrameric complex show that the four Ni(II) ions are ferromagnetically coupled, leading to a total ground spin state S_T = 4. Three analogous tetranuclear nickel hydroxamates were prepared from AHA and BHA and the appropriate dinuclear complex with either sy·dmen or asy·dmen as capping ligands.     

ANP and BNP Responses to Dehydration in the One-Humped Camel and Effects of Blocking the Renin-Angiotensin System

The objectives of this study were to investigate and compare the responses of atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) in the circulation of hydrated, dehydrated, and dehydrated losartan - treated camels; and to document the cardiac storage form of B-type natriuretic peptide in the camel heart. Eighteen male camels were used in the study: control or hydrated camels (n = 6), dehydrated camels (n = 6) and dehydrated losartan-treated camels (n = 6) which were dehydrated and received the angiotensin II (Ang II) AT-1 receptor blocker, losartan, at a dose of 5 mg/kg body weight intravenously for 20 days. Control animals were supplied with feed and water ad-libitum while both dehydrated and dehydrated-losartan treated groups were supplied with feed ad-libitum but no water for 20 days. Compared with time-matched controls, dehydrated camels exhibited a significant decrease in plasma levels of both ANP and BNP. Losartan-treated camels also exhibited a significant decline in ANP and BNP levels across 20 days of dehydration but the changes were not different from those seen with dehydration alone. Size exclusion high performance liquid chromatography of extracts of camel heart indicated that proB-type natriuretic peptide is the storage form of the peptide.We conclude first, that dehydration in the camel induces vigorous decrements in circulating levels of ANP and BNP; second, blockade of the renin-angiotensin system has little or no modulatory effect on the ANP and BNP responses to dehydration; third, proB-type natriuretic peptide is the storage form of this hormone in the heart of the one-humped camel.     

Antifungal compounds from induced Conium maculatum L.plants

The study has shown that furanocoumarins are the predominant antifungal compounds in Conium maculatum. These are found constitutively in the healthy plant but the amounts of these compounds in induced tissue may increase markedly in some cases, e.g. the concentration of isopimpinellin increased by 103-fold in the CuCl₂ induced leaves compared with that in the control. Since these compounds increase largely as a result of chemical stress these compounds can be considered, at least in part, as stress compounds. Variation in the amount and proportion of the antifungal compounds was observed in our study following treatment with various biotic and abiotic elicitors. CuCl₂ produced the largest increase in the amounts of antifungal compounds. The simple coumarin, umbelliferone was the main induced compound in the CuCl₂ treated leaves, xanthotoxin in inoculated leaves and in CuCl₂ treated seedlings of C. maculatum. Variation was also observed in the rate of accumulation of individual compounds using the unspecific elicitor CuCl₂.     

Gas exchange of root hemi-parasite Striga hermonthica and its host Sorghum bicolor under short-term soil water stress

The gas exchange of the upper fully expanded leaf of the root parasite Striga hermonthica and of its host Sorghum bicolor was measured under wet and dry conditions to identify the mechanisms of the devastating effects of the parasite on its hosts under drought. The short-term water stress severely reduced photosynthetic rate in infected sorghum, but less in S. hermonthica. Soil water stress did not affect leaf respiration rate in either S. hermonthica or infected sorghum. This suggests that under dry conditions both infected sorghum and S. hermonthica decreased autotrophic carbon gain. The transpiration rate of S. hermonthica, a major driving force for assimilate uptake from the host, was higher and less affected by water stress than that of infected sorghum. Stomatal density on the abaxial surfaces of the leaves was higher in S. hermonthica than in sorghum. Both S. hermonthica infection and water stress decreased stomatal conductance of the sorghum leaves. S. hermonthica, irrespective of soil water status, had greater stomatal aperture on the adaxial and abaxial surfaces of its leaves than infected sorghum. These results indicate that the higher transpiration rate of S. hermonthica even under water stress, achieved through higher stomatal density on the abaxial surfaces of the leaves and greater stomatal aperture on both surfaces of the leaves, may induce the maintenance of water and solute transfers from the host to the parasite leading to severe damage to the host under drought.     

Wide hybridization between oat and pearl millet belonging to different subfamilies of Poaceae

Oat (Avena sativa L.) and pearl millet (Pennisetum glaucum L.) belong to different subfamilies of Poaceae. When emasculated oat was pollinated by millet, fertilization took place and all seven millet chromosomes were retained along the complete haploid oat complement during early stages of embryogenesis. Fourteen days after pollination, we cultured 170 embryos onto rescue medium, of which 99 were attached with endosperm tissue. Twenty-one embryos germinated and showed shoot growth. One of them also developed roots. The shoots of the rootless embryos elongated, but rolled to the scutellum side and eventually died in light conditions. Chromosome observations and marker analyses indicated that the seedling plants were true hybrids that retained all of the oat and millet chromosomes. One exceptional embryo with shoot and root grew under light conditions. This was a haploid of oat and developed to a fertile adult plant. One embryo generated a callus after 6 months cultivation, and it was found to harbor four out of the seven millet chromosomes corresponding to linkage groups 2, 4, 6, and 7. The callus grew vigorously but did not develop shoots or roots.     

Intensive-Phase Treatment Outcomes among Hospitalized Multidrug-Resistant Tuberculosis Patients: Results from a Nationwide Cohort in Nigeria

Background

Nigeria is faced with a high burden of Human Immunodeficiency Virus (HIV) infection and multidrug-resistant tuberculosis (MDR-TB). Treatment outcomes among MDR-TB patients registered across the globe have been poor, partly due to high loss-to-follow-up. To address this challenge, MDR-TB patients in Nigeria are hospitalized during the intensive-phase(IP) of treatment (first 6–8 months) and are provided with a package of care including standardized MDR-TB treatment regimen, antiretroviral therapy (ART) and cotrimoxazole prophylaxis (CPT) for HIV-infected patients, nutritional and psychosocial support. In this study, we report the end-IP treatment outcomes among them.

Methods

In this retrospective cohort study, we reviewed the patient records of all bacteriologically-confirmed MDR-TB patients admitted for treatment between July 2010 and October 2012.

Results

Of 162 patients, 105(65%) were male, median age was 34 years and 28(17%) were HIV-infected; all 28 received ART and CPT. Overall, 138(85%) were alive and culture negative at the end of IP, 24(15%) died and there was no loss-to-follow-up. Mortality was related to low CD4-counts at baseline among HIV-positive patients. The median increase in body mass index among those documented to be underweight was 2.6 kg/m² (p<0.01) and CD4-counts improved by a median of 52 cells/microL among the HIV-infected patients (p<0.01).

Conclusions

End-IP treatment outcomes were exceptional compared to previously published data from international cohorts, thus confirming the usefulness of a hospitalized model of care. However, less than five percent of all estimated 3600 MDR-TB patients in Nigeria were initiated on treatment during the study period. Given the expected scale-up of MDR-TB care, the hospitalized model is challenging to sustain and the national TB programme is contemplating to move to ambulatory care. Hence, we recommend using both ambulatory and hospitalized approaches, with the latter being reserved for selected high-risk groups.