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Wednesday, 30 August 2017

Impact of irrigation with industrial treated wastewater on soil properties

8/30/2017
In large cities of developing countries, food demand is partially supplied by urban agriculture performed by smallholders involved in market-oriented farming. Although considered as an informal economy, urban agriculture generates significant incomes for the underprivileged part of the population, i.e. women and unemployed young people. However, urban farming is highly dependent on water availability.



Water availability is the main limiting factor for urban agriculture in arid and semi-arid regions. Such a problem is mostly seen in countries like sub-Saharan Africa where priority is given to industrial wastewater consumption. Large amounts of wastewater from household and industrial activities are discharged in water channels. Such effluents are rarely subject to suitable treatment and so they remain the only sustainable water resource available for farmers. There is no doubt that irrigation with wastewater increases the yield in agriculture as compared to irrigation with fresh water. This actually happens due to supply of essential nutrients like N, P & K present in wastewater.

Wastewater also contains heavy metals in greater amounts, so that it does not meet the quality criteria for irrigation water and imparts adverse effects on soil properties and quality. Main adverse impacts are soil salinization, sodication/alkalinization and structural changes which may result in dramatic yield increase. Soil sodication is associated with rise in soil pH which causes N, P, K & Zn deficiencies and formation of black alkali on surface of soil due to dissolution of organic matter. It may also result in clay dispersion. The black alkali is an indicator of soil alkalinization and it shows irreversible degradation of soil because organic matter is lost resulting in depletion of soil fertility.

According to Abbott and Hasnip (1997), Water with RAcalcite > 2.5 mmolcl-1 and EC < 4000µS cm-1 values (alkali water) may pose a threat to soil structure due to high amount of sodium. Irrigation with such wastewater changes the soil properties. Sodication induces dispersion of clay particles and a collapse of structural pores which causes obstruction of pores in subsurface horizon. Irrigation with wastewater also results in increase of bulk density and dramatic decrease in structural porosity.

Other causes, such as biological clogging due to the production of poly-saccharide and other organic compounds or physical clogging by suspended solids may be discarded in our situation, considering the relative small values of total suspended solids (205±157 mg l-1) and biological oxygen demand (107±50 mg l-1) of the effluent. Up to now, most studies about wastewater impacts on soil were limited to properties such as infiltration rate and hydraulic conductivity. The present study confirms a risk of strong degradation of hydro-structural properties when a soil is irrigated with alkaline and sodic wastewater, resulting in a dramatic decrease of soil fertility.



Conclusion:

Highly sodic and alkaline industrial effluents stemming from a microphyte sewage treatment plant used for irrigation led to quick soil structure collapse. As a result, dark deposits appeared at the soil surface of soils irrigated with wastewater. Chemical analysis clearly showed sodium and bicarbonates accumulation and pH increase to alkaline values in the topsoil of soil irrigated with wastewater. Physical analysis exhibited structural pore network of the soil collapsed dramatically, resulting in compact layers with poor water storage. Dissolution of organic matter leads to formation of black alkali at soil surface. It results in 50% decrease in yield.





About Author:
Miss Bushra Niamat
Institute of Soil & Environmental Sciences,
University of Agriculture, Faisalabad-38040, Pakistan

Wednesday, 9 August 2017

Tomato Leaf Curl Virus disease in Pakistan and its management; A Review

8/09/2017
Tomato (Lycopersicon esculentum) belongs to Solanaceae family is an important short duration vegetable crop attacked by many pathogenic diseases. TLCVD is most important which damage the crop very badly and affect the fruit quality and quantity badly. This disease is due to a complex of viruses which are transmitted through the whitefly. To manage the disease control of its vector is very important which is done by using different approaches. Management of TLCVD and B. tabaci through plants extracts, nutrients and insecticides are useful. Climatic conditions helps in development of disease as well as in management of disease. The management of this disease is very important due to the importance of this crop.




History and geographical distribution:

Tomato (Lycopersicon esculentum) belongs to Solanaceae family which also contain some other important crops such as potato, tobacco, eggplant and peppers. Tomato was originated from Latin America and spread throughout the world as vegetable crop. Tomatoes are very important due to short duration crop contributing a healthy diet by providing rich amount of minerals, essential amino acids, sugars, fibers etc. (Glick et al., 2009). A number of biotic and abiotic factors affect the quantity and quality of tomato fruit. Among the pathogenic diseases the viral diseases are most important. Tomato leaf curl virus is a serious threat to this crop. Basically it is a complex of viruses. This complex of viruses in Pakistan, India and Australia region is known as TLCV (tomato leaf curl virus) and in Israel and Europe region called as TYLCV (tomato yellow leaf curl virus (Pandey et al., 2009). TYLCV was reported firstly in Israel region in 1920 which appear in epidemic form in 1960 (Glick et al., 2009).

Symptomology and host range of TLCVD:



TLCVD affected plant show a number of symptoms which are reduction in leaf area as well as leaf size, stunted growth, puckering of leaf, upward curling, vein clearing, abnormal shoot proliferation, deformation of leaflets and reduction in yield quantity as well as quality. Tomato is the primary host of this disease. Some other plants are also acts as its host are bean (Phaseolus vulgaris), lisianthus (Eustoma grandiflourm) and petunia (Petunia hybrid) are also host plants of TYLCV. Some weeds including Cleome viscose (Caparidaceae) as well as Carton lobatus (Euphorbiaceae) are also susceptible against TYLCV but no disease symptoms are produce (Kurata et al., 2016).




Pathogen vector relationship:

Bemisia tabaci (whitefly) is a most important insect pest which harm the tomato plants by direct feeding and by transmitting the viral pathogen from diseased plant to healthy plant. Social and economics studied show that the farmer can gain up to 10 times more profit by growing resistant tomato against whitefly (Colvin et al., 2012).

Management of TLCVD and B. tabaci:

To manage this disease the control of insect pest vector is very important which is done by different methods. A few of them are as fallow

  • Management through plant extracts:

Chemical control method is the major method for the management of insect pest but it become less effective due to resistance develop in insect pest against the insecticides (Siebert et al., 2012). B. tabaci adults, nymphs and eggs are found resistant against the chemicals so plant extracts are used. As the chemical control of insect pest is costly so the plant extracts are more effective than the chemicals. Foliar spray of Neem (azadairachtin) and neem plus can kill the eggs, nymphs and adults of B. tabaci. Ethanolic and aqueous extracts of Annona squamosal, Carlowrightia myriantha, Trichillia arborea, Azadirachta indica and Acalypha gaumeri are effective against B. tabaci population. Neem oil, garlic and eucalyptus extract give significant result against this disease (Khan et al., 2013).

  • Management through insecticides:

The chemical control method is easy and most commonly used approach against the insect pest. A number of insecticides are used. Among them imidacloprid, acetamiprid, nitenpyram, thiamethoxam and diafenthiuron give significant result against aphids, whiteflies and other insect pests (Bacci et al., 2007). The comparative efficacy of these insecticides show significant result against this disease. These chemicals are very effective against the B. tabaci and TLCVD (Zeshan et al., 2015).

  • Management through nutrients and systemic acquired resistance:

Plant health play an important role the management of a disease. Nutrients play an important role in plant health which enable the plants to fights against the chewing type insects. Therefore the nutrients (N, P, K, Zn, and B) are very important in crop health and these nutrients were evaluated. The application of micro and macro elements can affect the relationship between the insect pest and plants. Studied shows that Zinc improve the defense system of plants. Plants with higher amount of N, P, K, and B give significant result against the disease. Some of these nutrients act as cofactor in enzyme activation (Maathuis et al., 2009).

Conclusion:

Tomato is cultivated in Pakistan and India also in other countries of Asia as well as throughout the world due to its high nutritional value and short duration crop. A number of biotic and abiotic factors affect the quantity and quality of tomato crop. Among the viral diseases TLCVD is very important which is a serious threat to tomato crop. To manage this disease it is very important to control its vector first. For this purpose a number of approaches are used which includes the management through plant extracts, through the nutrients and through the insecticides. Cultural practices, removal of host plant, vector control and crop rotation are also useful approaches against the disease.

References:

Bacci, L., A.L. Crespo, T.L. Galvan, E.J. Pereira, M.C. Picanço, G.A. Silva and M. Chediak. 2007. Toxicity of insecticides to the sweetpotato whitefly (Hemiptera: Aleyrodidae) and its natural enemies. Pest manage. Sci. 63(7): 699-706.
Colvin, J., N. Nagaraju, C. Moreno-Leguizamon, R. Govindappa, T.M. Reddy, S. Padmaja, N. Joshi, P.M. Hanson, S.E. Seal and V. Muniyappa. 2012. Socio-economic and scientific impact created by whitefly-transmitted, plant-virus disease resistant tomato varieties in southern India. J. Integrat. Agric. 11(2): 337-345.
Glick, E., Y. Levy and Y. Gafni. 2009. The Viral Etiology of Tomato Yellow Leaf Curl Disease. Plant Protect. Sci., 45(3): 81-97.
Khan, M.H., N. Ahmad, S. Rashdi, I. Rauf, M. Ismail and M. Tofique. 2013. Management of sucking complex in bt cotton through the application of different plant products. Pak. J. Life Sci, 1(01): 42-48.
Kurata, A., A. Fujiwara, N. Haruyama and T. Tsuchida. 2016. Multiplex PCR method for rapid identification of genetic group and symbiont infection status in Bemisia tabaci (Hemiptera: Aleyrodidae). J. Appl. Entomol. Zoo. 51(1): 167-172.
Maathuis, F.J. 2009. Physiological functions of mineral macronutrients. Current opinion in plant biology, 12(3): 250-258.
Pandey, P., N.R. Choudhury and S.K. Mukherjee. 2009. A geminiviral amplicon (VA) derived from tomato leaf curl virus (ToLCV) can replicate in a wide variety of plant species and also acts as a VIGS vector. J. Virol. 6(1): 152.
Siebert, M. W., J.D. Thomas, S.P. Nolting, B.R. Leonard, J. Gore, A. Catchot, G.M. Lorenz, S.D. Stewart, D.R. Cook, L.C. Walton, R.B. Lassiter, R.A. Haygood and J.D. Siebert. 2012. Field Evaluations of sulfoxaflor: a novel insecticide against tarnished plant bug (Hemiptera: Miridae) in cotton. J. Cotton Sci. 16:129–143.

Zeshan, M.A., M.A. Khan, S. Ali and M. Arshad. 2015. Correlation of conducive environmental conditions for the development of whitefly, Bemisia tabaci population in different tomato genotypes. J. Zool. 47(6): 1511-1515.







About Author:
Muhammad Jahanzaib
Department of Plant Pathology
University of Agriculture, Faisalabad-38040, Pakistan

Friday, 14 July 2017

THE MAGIC OF BIOTECHNOLOGY

7/14/2017
The word biotechnology brings into our minds and imagery whereby scientists are busy isolating gene fragments, DNA pieces and fitting them together like a jig-saw puzzle and then inserting them into an organism to get a novel product. While this may be true for genetic engineering, which happens to be a small branch of the subjects, biotechnology in essence is a field much broader than we can imagine.



One of the many facts of biotechnology is the field of bioinformatics. To a layman, it can be explained as the use of computational technology to further enhance our knowledge and approximate ideas about biological material based on its properties, which may not be identified experimentally. For instance, the soft wares developed today can assist in telling us whether a protein will be kept inside the cell or exported outside on the basis of simply the primary sequence of the protein. Similarly, the binding capacity of proteins to other molecules and the position of binding can be visualized using computational techniques. This is a very important tool in drug delivery since it helps to design target specific drugs that can be used to cure fatal diseases like dengue fever and AIDS.


An emerging sub-field of biotechnology in this regard is that of pharmaco-genomics which is also referred to as personalized medicine. This involves the use of drugs for treatment according to the genetic characteristics of patients so as to avoid any complications that may arise as a result of allergic reactions as well as to ensure maximum efficacy of the drug. This is particularly helpful in the treatment of diseases like cancer, diabetes, tuberculosis and cardiovascular disease.

The branch of biotechnology known as, medical biotechnology also aims to find a cure to human suffering and to reduce the potential risk of diseases. While this includes the discovery and use of penicillin that happened centuries ago, and the production of recombinant insulin that originated in the last few decades, medical biotechnology has much more to offer. It deals with the designing of drugs as well as with methods to cure the disease by exploiting the natural body mechanism for it. Tissue grafting, organ transplantation, antibody engineering, vaccine production and many such breakthroughs are a reality in the world today, only because of this field of biotechnology.

Another aspect that governs life and health in particular is the environment and biotechnology with it claim to benefit human life, takes care of this aspect as well. Bio-remediation caters to removal of toxic compounds from soil, water and air using microorganisms or plants. This mechanism of removal exists naturally in some plants and microorganisms. 

Biotechnology has further enhanced the ability of these indigenous life forms to clean the environment. Heavy metals, chlorofluorocarbons, oils and harmful radioactive compounds are among the few toxic materials that can be removed using bio-remediation, and this is by no means that only way biotechnology is helping to clean the environment. The designing of cleaner fuels such as bio-diesel and bio-ethanol is the first step towards reducing the pollution resulting from the use of fuels including petroleum products. The best part is that contrary to the common thought, the production of these fuels, for instance bio-gas, is cheap and can be done in a very easy set up.

Fermentation technology is one of the oldest branches of biotechnology. From enzymes used in detergents, to yeast used in bread making, this one aspect of biotechnology has benefited mankind for centuries. Even this aspect has undergone modification over time making it easy to recover products based on their properties. Affinity chromatography, ion exchange chromatography and size exclusion chromatography are among the few techniques that are used to purify the proteins and enzymes produced by fermentation.

These are thousands of other uses of biotechnology with practical applications that are being used globally to enhance healthcare, disease prevention, clean the environment, increase food safety, and provide safe, purified products. So, it is about time that we get rid of approach towards biotechnology thinking that it only deals with genetic engineering and open our minds and eyes to the magic this field has created around us.


Since the last two decades, the dengue incidences have been increased rapidly which has brought many groups including: The Pediatric Dengue Vaccine Initiative (funded by Bill and Melinda Gates foundation), the WHO, the US military, as well as industry and governments in many different countries to collaborate together in the hopes of accelerating the development of a successful vaccine. With our better understanding of the virus particle several vaccine candidates are now showing promise in clinical studies, with the most advanced candidate having phase 3 testing.





About Author:
Miss Ayesha Maqbool
Department of Microbiology,
University of Agriculture, Faisalabad-38040, Pakistan

Monday, 19 June 2017

Application of copper and silver nano-particles for enhancing callus induction and regeneration of wheat

6/19/2017
Wheat being a major crop of the world covers about 17 percent of the total world cultivated land and plays a vital role in world food supply but the low yield of wheat creates a gap between demand and supply. To meet and full fill the demands of rapidly increasing human population wheat yield must be significantly increase up to 40 percent by 2030. Use of modern techniques for example In vitro tissue culture technology that involves callus induction and regeneration phase, recombinant DNA technology, genetic transformation and nanotechnology can make possible to increase the wheat yield as well as quality. Tissue culture technique is very much important for genetic transformation and it offers the establishment of variation by gametoclonal and somaclonal variations and these variations can be used for crop and plants improvement and development programs.



Flourishing tissue culture for all plants mostly depends upon the elimination of endogenous as well as exogenous contaminating microbes which are major problems of tissue culture technology.

Therefore nanotechnology, a revolution of 20th century can be used to overcome these problems associated with tissue culture techniques. Nanotechnology is basically synthesis and application of nano-particles with size range of 1-100 nano-meters. Properties of metallic NPS (nano-particles) are totally dissimilar than bulk materials which are made from same atoms of same element. Nano-tech is most promising and valuable technology which could be applied in almost every part of life. The efficiency and use of nanotechnology totally depends on nano-particles types, size and their shapes. Several types and groups of nano-particles have different and specific uses in relevant fields for example metallic, magnetic, nonmetallic oxides, nano-tubes and carbon nano-particles. SNP’s has its potential as an anti-microbial agent. SNP’s shows different ways of inhibitory actions to different microorganisms; it can also be used to control a variety of plant pathogens very effectively and comparatively in more secure method as compared to most of synthetic fungicides. Copper nano-particles are reported to have antimicrobial activity against a number of species of bacteria and fungi. 

Previous studies have indi­cated that copper nanoparticles have antimicrobial activity against E. coli and Staphylococcus species, and similar antifungal properties were also reported by higher concentrations.

For the same purpose we can use different concentrations of copper and silver nanoparticles to enhance the callus induction and regeneration efficiency of wheat. We prepare their nanoparticles by biological methods to avoid any harmful and residual effects

3AgNO3+Na3C6H5O7.2H2O → C6H5O7+NaNO3+CO2+3Ag+2H2O


                   
First of all different concentrations of 2, 4-D, BAP and NAA were used to optimize the best protocol for callus induction and regeneration Optimum concentrations of 2, 4-D (3.5 mg/l) + BAP (0.5 mg/l) shows maximum callus induction of 88% and 65% for embryogenic callus induction. For being optimized levels of 2, 4-D and BAP, 40 ppm Ag NPS shows 100% callus induction and 10 ppm Cu NPS shows 64% embryogenic callus induction. Maximum callus regeneration was observed for 40 ppm concentration of silver nano-particles which was 88% and 30 ppm concentration of copper nano-particles which was 77%.

Visual observations show that callus induced with silver nano-particles of concentrations 30 ppm and 40 ppm were the best embryogenic calluses, having very impressive lush white or off white color with green spots, which shows their embryogenic behavior because shiny white, hard, compact, granular and green spotted calluses is mark of identification for embryogenic callus and results show that they exhibit best regeneration.






However different concentrations of copper nanoparticles showed reduced results for both callus induction and regeneration percentage as compared to silver nanoparticles but much  better than controlled treatments. Over all silver nanoparticles show good results for callus induction and regeneration. Most important role of Silver nanoparticles was observed as its anti-microbial activities which are required to be further exploration.





About Author:
Mr. Ali Raza
M.Sc. (Hons.) Agri-Biotechnology
Centre of Agricultural Biochemistry and Biotechnology (CABB). University of Agriculture, Faisalabad, Pakistan.

Friday, 2 June 2017

Scientists are unable to produce the Zika virus vaccine. Why?

6/02/2017
Zika virus is an arbovirus, belongs to the genus Flavivirus and family Flaviviridae. Phylogenetically, it resembles very much to other viruses such as Japanese encephalitis, West Nile virus, dengue and yellow fever. Zika virus is mosquito borne RNA virus. Genus Aedes transmits the Zika virus. In 1947 during the study of the transmission of jungle yellow fever in the Zika forest of Uganda, it was firstly isolated from a Rhesus macaque. Then in the united republic of Tanzania and in Uganda it was isolated in humans in1968. Successively, epidemics have been recorded in Asia, Africa, the western pacific region and, more lately, in the Americas. Zika is generally a slight illness, causing rash and joint pain, fever and usually tenacities within seven to ten days. Zika vaccine has not been on the radar, because the cost in developing the Zika vaccine is US$160-500 million and previously low impact of the virus. But now has explosively spread in the Americas. This virus has latent links with microcephaly (brain damage and reduce head size) in the babies of pregnant women.



Research on Zika virus:

Now scientists are doing research that is needed to cultivate vaccine. There is very little information about the replication of Zika, how it grounds disease, or how the immune system defends against disease. The ideal vaccine prompts a stout response from the immune system, gives long-term defense with fewer doses, without side effects. Though rapidly developing such a vaccine is hardly this simple. It’s early days, but researchers from the Butantan Institute in Brazil, Public Health Agency of Canada and the US National Institutes of Health have started research on Zika vaccines. These scientists may have nominees ready for initial clinical trials just before the end of the year. Although full supervisory authorization of a successful vaccine would take many years, it could possibly be used in public health disasters within a year.

Complications in producing the vaccine:

There is no formula for ideal vaccine. Although the ever-increasing complexity of vaccine technology, formulation of vaccine frequently comes down to “suck it and see”. Many vaccines look favorable in pre-clinical testing, only to fall over during the low and the affluent clinical trial process. A Type of immune response to many infectious diseases is the most operational in providing defense. Since vaccines prompt a protective immune response against infection, this can make vaccine plan very challenging. Vaccine protection is a major issue. The most effective vaccines are “Live” or “attenuated” vaccines that implicate a related or weakened form of the pathogen. But there is still the prospective for these vaccines to grounds disease, especially in receivers with weakened immune system. Vaccines require a log process of clinical trials and impost by supervisors before they are ratified for repetitive human use. This is an essential process, but it sets a very high price of authorization. The smallpox vaccine is the most successful vaccine that is ever produced. This is a live vaccine and would most likely not have been ratified by today’s controllers due to safety fears.

Crucial significance:


Zika grounds mild fever in humans that on its own does not make a strong dispute for a vaccine. But the possible link to microcephaly in unborn children, even though not yet definitely confirmed, makes vaccine development – and necessary funding – an urgent priority. It’s also important to fund basic research to provide a necessary facilitator for current and future vaccine development programs. In  the time being, people in affected areas, including travelling, should mind out to avoid mosquito bites by using repellents and wearing long clothing, window screens and bed nets.





About Author:
Miss Sabahat Abdullah
M.Phil Microbiology
University of Agriculture, Faisalabad-38040, Pakistan

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