Impatti, adattamento e vulnerabilita Le cause e le responsabilita dei cambiamenti climatici sono state trattate sul numero di ottobre della rivista Cda. Approfondiamo l’argomento presentando il documento: “Cambiamenti climatici 2007: impatti, adattamento e vulnerabilita” votato ad aprile 2007 dal secondo gruppo di lavoro del Comitato Intergovernativo sui Cambiamenti Climatici (Intergovernmental Panel on Climate Change). Si tratta del secondo di tre documenti che compongono il quarto rapporto sui cambiamenti climatici.

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Climate Change 2007: Impacts, Adaptation and Vulnerability.

The Pennsylvania Environmental Public Health Tracking (EPHT) program tracks a set of Nationally Consistent Data and Measures (NCDMs) in order to compare different states and over time. Drinking water quality indicators, including levels of nine contaminants in public water, and a measure of annual public water use are included in the set of NCDMs available on the Enterprise Data Dissemination Informatics Exchange website. The nine contaminants are: arsenic, atrazine, di(2-ethylhexyl) phthalate (DEHP), haloacetic acids (HAA5), nitrate, tetrachloroethene (PCE), trihalomethane (THM), trichloroethene (TCE) and uranium.

To the drinking water quality

Laboratory control of antimicrobial therapy

Antimicrobial potential of bacteriocins: in therapy, agriculture and food preservation.

All metal oxide nanoparticles influence the growth and development of plants. They generally enhance or reduce seed germination, shoot/root growth, biomass production and physiological and biochemical activities. Some plant species have not shown any physiological change, although significant variations in antioxidant enzyme activity and upregulation of heat shock protein have been observed. Plants have evolved antioxidant defence mechanism which involves enzymatic as well as non-enzymatic components to prevent oxidative damage and enhance plant resistance to metal oxide toxicity. The exact mechanism of plant defence against the toxicity of nanomaterials has not been fully explored. The absorption and translocation of metal oxide nanoparticles in different parts of the plant depend on their bioavailability, concentration, solubility and exposure time. Further, these nanoparticles may reach other organisms, animals and humans through food chain which may alter the entire biodiversity. This review attempts to summarize the plant response to a number of metal oxide nanoparticles and their translocation/distribution in root/shoot. The toxicity of metal oxide nanoparticles has also been considered to see if they affect the production of seeds, fruits and the plant biomass as a whole.

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Plant Response to Engineered Metal Oxide Nanoparticles.

Objective
To isolate, evaluate and characterize potential antibiotic producing actinomycetes from water and sediments of Lake Tana, Ethiopia.

Isolation and characterization of potential antibiotic producing actinomycetes from water and sediments of Lake Tana, Ethiopia

In recent years, drought has been a serious problem in Ethiopia and elsewhere which has adversely affected plant productivity. This study aimed to investigate the effects of water stress on growth, biomass and foliar characteristics in three cultivars (Brukitu, Tegegnech and Adi) of Pisum sativum. The control plant pots were uniformly irrigated at 3 day intervals to maintain 100% field capacity. Water-stress conditions were imposed by subjecting plants to a gradual decrease of soil water availability such as watering at 6 day intervals (slight-stress condition), 9 day intervals (mild-stress condition) and 12 day intervals (severe-stress condition). Results revealed significant differences among the cultivars, water-stress treatments and their interaction, indicating the cultivars variability and differential response to water stress. Water stress adversely affected growth, biomass production, leaf water status and other leaf characteristics such as pigment concentration (chlorophyll a, b and total chlorophyll), maximum quantum yield of photosystem II (PS II) (Fv/Fm), net photosynthetic rate, stomatal conductance and transpiration rate in all cultivars, as stress level was increased in comparison to control plants. The relatively less decline in the studied parameters of Tegegnech exhibited a reasonable tolerance ability of this cultivar, whereas Brukitu and Adi proved to be sensitive to water-deficit condition.

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Differential sensitivity of Pisum sativum L. cultivars to water-deficit stress: changes in growth, water status, chlorophyll fluorescence and gas exchange attributes.

Plants are rich in secondary metabolites and are being used for the treatment of various ailments in the indigenous system of medicine. Many developing countries are facing illnesses, and deaths among children are caused by germs, which get into the mouth via water and food. In addition, it has been estimated that up to 80% of all disease and sickness in the world is caused by inadequate sanitation, polluted water or unavailability of water. Thus, this study investigates the water purifying property of Moringa oleifera seed powder and determines the role of seed extracts against a few bacterial growths. Water samples were obtained randomly during January and February, 2015, from the Angereb and Shinta rivers, Gondar, Ethiopia. Both sites of water samples were subjected for purification studies and treated with dried seed powder. Treated water samples were subjected to bacteriological analysis using most probable number technique. Addition of aluminum sulfate as a coagulant lowered the water pH from 7.2 to 3.66, while the seed extract water pH remained the same. Treatment of 0.016 g/L of M. oleifera decreased water turbidity from 208.3 nephelometric turbidity units (NTU) to 33.66 NTU (83.84%) and from 129 NTU to 16.8 NTU (86.98%) for the Shinta and Angereb river water samples, respectively. The highest microbial load reduction was found with the Angereb (97.17%) and Shinta (97.50%) rivers. The acetone extracts showed maximum antibacterial activity with 19.00 mm against Salmonella typhii (clinical isolate), while Shigella dysenteriae (clinical isolate) was the least sensitive with 7.66 mm on the aqueous extract. The most frequent MIC value was 6.25 mg/mL followed by 12.5 mg/mL. The acetone extract is the most potent in inhibiting and killing the test organisms at a very low concentration for Shigella typhii. Taken together, the seed powder exhibits a remarkable reduction in turbidity and coliform count which makes the seed powder a good source for water purification. The acetone extract of seed had a strong antibacterial activity. It reveals that the seed powder and its extract can control and reduce waterborne bacterial diseases. This investigation facilitates benefits to those who cannot afford and or have access to clean drinking water in Ethiopia and elsewhere.

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Water purification and antibacterial efficacy of Moringa oleifera Lam

Background: Accesses to safe water is a universal need however, many of the world’s population lack access to adequate and safe water. Consumption of water contaminated causes health risk to the public and the situation is serous in rural areas. Objectives: To assess the bacteriological and physico-chemical quality of drinking water sources in a rural community of Ethiopia. Methods: Water samples were collected from tap, open springs, open dug wells and protected springs for bacteriological analysis of total coliforms and thermotolerant coliforms. The turbidity, pH and temperature were measured immediately after collection. Results: Most drinking water sources were found to have coliform counts above the recommended national and international guidelines and had high sanitary risk scores. There was a statistically significant difference among water sources with respect to TC and TTC (p < 0.05) and there was a statistically significant positive correlation between coliform counts and sanitary risk scores (p < 0.01). Most water sources didn’t satisfy the turbidity values recommended by WHO. Conclusion: The water sources were heavily contaminated which suggested poor protection and sanitation practice in the water sources. Source protection strategies as well as monitoring are recommend for this community. Keywords : Coliforms; physico-chemical; rural community; water quality African Health Sciences 2013; 13(4): 1156- 1161

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Bacteriological and physico-chemical quality of drinking water sources in a rural community of Ethiopia.

Objective To evaluate the antibacterial activities of the crude leaves extracts of Zehneria scabra (Z. scabra) and Ricinus communis (R. communis) against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and methicillin resistance S. aureus. Methods The crude powdered leaves of Z. scabra and R. communis were extracted successively by organic solvents in increasing polarity [benzene, chloroform:acetone (1:1), 70% alcohol and distilled water]. The antibacterial susceptibility of the crude leaves extracts of were tested against standard strains of E. coli (ATCC 25922) and S. aureus (ATCC 2923) and clinical isolates of E. coli, S. aureus and methicillin resistance S. aureus using agar well diffusion method. Results In Z. scabra and R. communis leaf extracts, the most sensitive standard strain was S. aureus with an inhibition zone of (14.00±1.20) mm and (15.90±2.13) mm, respectively. The minimum inhibitory concentration (MIC) values of Z. scabra extracts against test organisms ranged from 1.95 mg/mL for extract 3 in clinical and standard strains of S. aureus to 250 mg/mL for extract 1 and 4 in clinical and standard strains of E. coli. The MIC values of R. communis extracts against test organisms ranged from 1.95 mg/mL for extract 2 and 3 standard strains of S. aureus to 250 mg/mL for extract 1 in clinical isolate of E. coli. Most of the minimum bactericidal concentration and MIC values of plant extracts were almost similar particularly in R. communis, or minimum bactericidal concentration equal to one dilution factor less than MIC value of the extracts mainly in Z. scabra. Conclusions The potency of plant extracts against test organisms were depend on different organic solvents used. Clinical isolate of bacterial pathogens showed less zones of diameter compared to the standard strains. Gram-positive had wide inhibition zones than Gram-negative bacteria. Further studies should be carried out to isolate the pure compounds and standardization of the methods of plant extracts for an in vitro testing.

In vitro antibacterial activity of leaf extracts of Zehneria scabra and Ricinus communis against Escherichia coli and methicillin resistance Staphylococcus aureus

Samuel Sahile

Papers

Isolation and characterization of potential antibiotic producing actinomycetes from water and sediments of Lake Tana, Ethiopia

Differential sensitivity of Pisum sativum L. cultivars to water-deficit stress: changes in growth, water status, chlorophyll fluorescence and gas exchange attributes.

Water purification and antibacterial efficacy of Moringa oleifera Lam

Bacteriological and physico-chemical quality of drinking water sources in a rural community of Ethiopia.

In vitro antibacterial activity of leaf extracts of Zehneria scabra and Ricinus communis against Escherichia coli and methicillin resistance Staphylococcus aureus