This blog covers the entire domain of sericulture. It is designed for providing a common platform for discussion between scientists, policy makers and students in the field. reproduction of content from this blog with due acknowledgement is encouraged.

Tuesday, 3 July 2007

Exclusive interview with Dr. Panomir Tzenov, Executive Director of Bulgarian National Center of Agricultural Sciences (NCAS)


Dr. PANOMIR IVANOV TZENOV was born in Vratza, Bulgaria in 1961. He took his MSc from The University of Zootechnics and Veterinary Medicine – Stara Zagora in Animal breeding engineering – sericulture. He obtained his PhD. in sericulture in 1996.
Dr. Tzenov started his career as a technologist in silkworm egg production at the “Silkworm breeding and egg production enterprise”, Vratza, under the Sericulture Experiment Station (SES) Vratza. He became the head of the station in 1987. From 1994 to 2003 he served as The Director of SES, Vratza and as National Director of the project “Rehabilitation of sericulture”, financed by FAO during 2000 – 2002. Presently he holds the position of Executive director of Bulgarian National Center of Agricultural Sciences (NCAS), Sofia.
He is member of various reputed national and international forums such as International Working Group on Sericulture Germplasm” under FAO, International Working group on the global silk handcraft cottage industries and silk enterprises development” under FAO, The Publishing council at the National Center of Agricultural Sciences, Bulgaria etc. He is the founder president of Black, Caspian Seas and Central Asia Silk Association (BACSA).
He has contributed immensely to general sericulture, silkworm breeding, egg production, rearing technology and cocoon and silk processing. He has 164 published papers to his credit and holds author’s certificates for two commercial silkworm hybrids.
Dr. Tzenov is widely traveled and has participated in more than 30 scientific conferences across Asia and Europe.

Inspite of his busy schedule he has found time to give an exclusive interview to 'The Silkworm' for which The Silkworm is thankful.


Tell me about BACSA, its objectives, membership, mode of operation etc.
The Black, Caspian Seas and Central Asia Silk Association (BACSA) was established after the “International Workshop on Revival and Promotion of Sericultural Industries and Small Enterprise Development in the Black, Caspian Seas and Central Asia Region”, organized by FAO in cooperation with the Government of Uzbekistan and held at Tashkent, Uzbekistan from 11 to 15 April 2005 in order to promote sericulture production in the region countries. The association’s main tasks are to: Generate sericulture projects from external resources, including bilateral and multilateral cooperation; Sensitize respective governments and prospective donors; Promote local and regional joint efforts which allow the cooperation between the countries of the Black, Caspian seas region and Central Asia to develop concrete actions that fortify the sustainable development of the sericulture in the region; Promote making agreements for international scientific-technical cooperation and business relations between the countries involved and Promote market studies, training, and dispersion of sericultural germplasm, and silkworm eggs.

For the operation of the association there are, chosen democratically by the members a President, two Vice-presidents, national coordinators for each member country, members of an Executive Committee. The members of the Executive Committee are directly the people in charge of coordination of all the raised activities for their country, within the regional context. The Executive Committee it is the bridge between the country, the national coordinator and the other countries of the association, to execute the actions defined in the region.

The Committee gathers at least once a year and has the following functions: to evaluate the work made by each national coordinator in activities of coordination in her/his country with respect to the BACASA, to recommend the names of the people in the association to receive training abroad. to evaluate and to watch the handling of the "Rotary Funds" and "Research Funds" that will be probably created and to give the recommendations on orientation and better use of these resources, to present/display the research proposals that require financing on the part of the "Research Fund", to approve the necessary resources for this aim and to give recommendations and suggestions on all publications and written material that takes place within the frame of the BACASA and to advise to the association’s President on the advances and progresses that must take place in the development of the activities and give recommendations her/him on the modifications and corrections that are due to make for the final succes of the projects.
Is sericulture a dying enterprise? Does it have a future?
The status of sericulture depends on many factors. In some countries it is really a dying enterprise, due mainly to their high economical development, combined with lack of any governmental support. On the other hand the selling of raw silk/silk allied products by the Chinese at too low prices during the period 1995 – 2005 led to a collapse of the sericulture industry in many countries. The Chinese sold 1 kg of raw silk for US$ 16-18/kg, 3 A quality. That means the fresh cocoon purchasing price should be about US$ 0. 50 – 0.80. Very few countries have so poor farmers who are ready to produce cocoons at this price. On the other hand in many countries the sericulture farmers are supported by the government. In the last year the raw silk price in China jumped to about US$ 43/kg. Therefore the increasing price of the raw silk at the international market, combined with stable state policy to support the sericulture development are the two key factors for the bright future of sericulture. The availability of local silk market is also very important.
Silkworm rearing within the European union countries is considered as one of the protected and promoted activities, being subsidized by Euro 133 per box of 20.000 eggs. This subsidy creates a considerably high income to the farmer, since it approximately duplicates his total income, added to the cocoon value. The replacement of traditional crops by perennial mulberry cultivation is additionally subsidized by the EU by means of the initial installation cost and the income loss for twenty years.
Considering the above I can make the final conclusion that the sericultural industry has a good future.
What is the relevance of sericulture as an agro industry in the developing and underdeveloped countries?
Apart from giving a high-value product, sericulture is a highly women/old people- focused, labour intensive, rural based, income leveler. From one hectare of irrigated mulberry, from the stage of mulberry cultivation to the stage of weaving and marketing, about twelve persons get employment throughout the year. Since the producers of silk cocoons are mostly small farmers while the costly silk final products can be purchased only by the affluent, it transfers income from the rich to the poor, from the urban to rural families. Internationally also, the silk producing countries are mainly the developing countries while silk products have a high demand in the EU countries, Japan and the USA.
Sericulture is also a drought-proffer because, the mulberry plant whose roots go deep in the soil, does not die during prolonged drought and its leaves will sprout whenever there is rain. In the tropical countries, even with 40% rainfall, there will be two crops of mulberry instead of the normal four or five which means, even in the worst drought year, there will be 40% of normal income for the sericulture families. In some temperate /subtropical countries where the summer is very dry and autumn rearing is impossible without irrigation, is possible to get at least one spring cocoon crop without any irrigation of mulberry.
Sericulture thus scores on every point: One of the highest income from one unit of land; Use of less water and drought resistance; Income leveler - transfer of income from rich to the poor nationally and internationally; Generating high rural employment; Gender benign in favor of women-employment; Silkworm rearing is indoors and has no arduous work-drudgery; A natural fibre and ecologically harmless; Hygroscopic, absorbs body moisture and therefore comfortable to wear; No synthetic substitute and highly demanded in EU countries and the USA; No competitor to food crops.
However, in new areas initial promotion and investment is needed in the establishment stage. This is because, while mulberry can be grown without much difficulty, the art and science of silkworm rearing, marketing arrangements for cocoons, reeling and weaving have to be organized in the initial stages till the industry takes root.
The reeled silk yarn is not perishable and being a low-volume, high-value product it has a ready market and can be transported easily. In fact across countries it is air-freighted and not sent by surface transport as transport cost is a small fraction of the total cost. The more difficult task is the teaching of rearing and organizing of reeling to create a market for cocoons produced by the farmer. Once these two aspects are taken care of, sericulture will entrench itself and will develop. Silk being a natural fiber and hygroscopic, it is comfortable to wear in all seasons as it absorbs body moisture. Sericulture thus fits neatly into the economy of any developing country with a significant rural sector, for quite a few decades to come.
Silkworm has long been identified as a laboratory tool (courtesy Dr. Tazima) but yet to be exploited as one. Why is it so?
Recently the silkworm was used as a laboratory tool for the medicine purposes.
The silkworm genome project is underway. What are its implications to the scientific field and agricultural (sericulture) field?
Scientific field: getting new scientific information about the animal genome.
Agricultural field: creation of new silkworm breeds and hybrids combining precious characters, for example sturdiness with high productivity.
While considering the long history of domestication, the bulk of breeding experiments done, viability to genetic manipulation, genomic information, versatility of sericigenous fauna etc., do you think paucity of competent researchers has been the worst handicap for the sector? What are your suggestions for a remedy?
I do not think that paucity of competent researchers has been the worst handicap for the sector. There are many other reasons, the main ones – insufficient financing, considering the sericulture as a minor sector etc.

Dr. Panomir Tzenov can be contacted at panomir@yahoo.com. For more information on BACSA visit http://www.bacsa-silk.org/index.php?lang=bu

Wednesday, 27 June 2007

Good news for silk

The provisional production figures released by the Central Silk Board (CSB) revealed that domestic raw silk production is showing an upswing with a record of 18760 tons of raw silk during fiscal 2007. The upward move represents 8.41 percent surge over the previous year figures of 17305 tons; however, the record production was much more than the peak production of 17351 tons achieved in 2001-02. During 2002-03 and 2003-04, the drought conditions in the southern region had deterring effect in silk production as farmers went to the extent of even uprooting the mulberry plantations; whereas the ill effects of the severe drought appear to thin out as mulberry silk production had gathered momentum for the fourth successive year.
Last year, the mulberry silk production, including that of bi-voltine silk was 16805 tons up from 15445 tons from the previous year. The redeeming factor of last year's production however was the signs of superior bi-voltine silk galloping in growth by 12.77 percent to cross the 1000 ton mark.
However, the increase in production only proves that bi-voltine silk had come to stay and was finding increased acceptance at farmer's level every year. For more related news visit http://www.bharattextile.com/newsitems

Friday, 15 June 2007

Heat shock proteins – a forgotten link in Silkworm breeding for robustness

Silkworm is one of the most thermal-sensitive organisms. Intensive and careful domestication over centuries has apparently deprived the insect of opportunities to acquire thermo tolerance. Among many factors attributed to poor performance of the bivoltine strains under tropical conditions the major aspect is that many quantitative characters decline sharply when temperature is higher than 28°C. The risk of hybridization of polyvoltine to bivoltine could not be taken due to the delay in fixation of economic characters. The long and hard struggle to evolve robust-productive silkworm hybrids has not so far met with satisfactory results.

The front ranking breeders in the field agrees to the fact that it is a difficult task to breed such bivoltine breeds, which are suitable to high temperature environment and yet productive. Therefore means other than the conventional breeding methods are to be adopted to attain the goal. With the aid of modern biotechnological tools it may be possible to quantify the factors responsible for the expression of temperature tolerance. Resistance to high temperature has been recognized as a heritable character in silkworm and the possibility for temperature tolerant silkworm races were suggested by Kato as early as 1989. Thorough understanding of the phenomenon of temperature tolerance in silkworm is an essential pre requisite for attaining any results in this direction.

Heat Shock Proteins

It is known that rapid heat hardening can be elicited by a brief exposure of cells to sub-lethal high temperature, which in turn provides protection from subsequent and more severe temperature. In 1962, Ritossa reported that heat and the metabolic inhibitor dinitrophenol induced a characteristic pattern of puffing in the chromosomes of Drosophila. This discovery eventually led to the identification of the heat-shock proteins (Hsp) or stress proteins whose expression these puffs represented. Beginning in the mid-1980's, investigators recognized that many Hsps function as molecular chaperones and thus play a critical role in protein folding, intracellular trafficking of proteins, and coping with proteins denatured by heat and other stresses. Accordingly, the study of stress proteins has undergone explosive growth.

Heat-shock proteins are classified into families on the basis of sequence homology and typical molecular weight as Hsp 110, Hsp 100, Hsp 90, Hsp 70, Hsp 40, Hsp 10 and small heat- shock protein families. In eukaryotes many families comprise multiple members that differ in inducibility, intra cellular localisation and function.


Extensive studies have been conducted on the heat- shock response in insects such as Drosophila, Chironomous, Lymantria dispar, the tobacco hornworm-Manduca sexta, the desert ant-Cataglyphis, the fleshfly-Sarcophaga crassipalpis, the locust Locusta migratoria etc. There are reports on the activity of hest shock proteins in silkworm. Evegnev et. al. (1987) studied heat shock response in Bombyx mori cells. Temperature elevation induced active transcription of heat shock mRNAs in infected cells. But at the level of translation headstock treatment failed to induce hsp synthesis and was not able to inhibit production of polyhedrin in such cells.

Joy and Gopinathan in 1995 reported the appearance of 93, 70, 46 and 28 kDa protein bands consequent to high temperature exposure in Bombyx mori. in both bivoltine and multivoltine strains, but with variying kinetics. Lee et.al., in 2003 cloned a genomic DNA fragment containing a promoter region for the gene encoding an HSC70-4 homologue, the structure of which was deduced from the partial cDNA sequences that were registered in a Bombyx mori EST date base. The deduced amino acid sequence with 649 residues was 89% and 96% identical to those from Drosphilla melanogaster hsc-4 and Manduca sexta HSC-70-4 respectively. The expression analysis by reverse transcription PCR demonstrated that mRNA transcription occurred in all tissues examined and was not stimulated by heat shock. Thus HSC70-4, the molecular chaperon is ubiquitously expressed in every tissue of Bombyx mori.

Considering the enormous investigations conducted on HSPs in a plethora of organisms ranging from bacteria to man, it is felt that there is an acute shortage of literature on the heat shock response of the silkworm Bombyx mori. There is dire necessity for 1. Understanding the molecular mechanism of temperature tolerance in silkworm. 2. Identification of the various families of HSPs synthesized and the threshold temperature, which induce their expression. 3. Understanding the differential expression pattern of various HSPs in bivoltine and polyvoltine races and 4. To locate the genes responsible for the heat inducible HSPs and subsequent steps to introgress the same into the bivoltine genome either by conventional breeding or by use of molecular techniques.

Thursday, 7 June 2007

An experiment on Temperature induced protein synthesis

Differential Expression Of Temperature Induced Protein Synthesis In Two Races of Silkworm Bombyx mori.L
A study was conducted to analyze the differential expression of temperature induced protein synthesis in two silkworm races exhibiting different temperature tolerance. A temperature tolerant race namely Nistari and another temperature non-tolerant race namely CSR2 were used for the study. Experimental animals of both the races were subjected to high temperature treatment at 36°C and 40°C for two different durations, viz., 1 h and 6h on the 2nd day of 3rd, 4th and 5th in star. Proteins purified from the haemolymph collected from the treated larvae immediately after treatment and after four recovery periods (1h, 6h, 24h and 48h) were subjected to SDS PAGE analysis to observe the protein kinetics. The protein profiles of both the races under various treatments when compared with control indicated deviations mostly in the 68-97 kDa region apart from the appearance of new bands. Both the races showed similar protein banding patterns, though the intensity of the bands varied with treatments. Induction of absolutely new bands was observed in the of 97-205, 68-97 and 29-43 kDa molecular weight region possibly representing Hsp: 100, 90, 70 and 34-35kDa. Families. The results are indicative of the differential capability of the races to respond to heat shock by temperature induced protein synthesis. The study results suggest the possibility of using heat shock protein based breeding strategy for inducing robustness in productive breeds.


Hi everybody

I started this blog in honour of the silkworm, a tiny animal belonging to class insecta which produce one of the most sought after materials by man- silk. I wish to cover everything related to this humble creature. Its history- more than 4000 years old; the emperors who adored it- Huang- De of China to Tippu of India, the path it had travelled - the dry deserts of Takli makkan to the snow clad peaks of Himalaya, its biology - of interest to entomologists, microbiologists, pathologists, anatomists, physiologists and molecularbiologists; its economic uses - of interest to women, men the rich and the poor and finally its future possible role on the fate of many countries. Please visit this blog again.

The metamorphosis is in progress.......................
HTML Comment Box is loading comments...

Followers

My Blog List