Alteration in the primary metabolites in three different tissues of silkworm, Bombyx mori L. under the influence of a Juvenoid, R394

A bivoltine silkworm hybrid, KA x NB4D2 was treated with the juvenoid R394 (Ethyl-9 cyclohexyl-3,7-dimethyl-2,4-nonadienoate) at a dose of 0.039 nl/larva at 24, 48, 72 and 96 h of 5th instar for silk yield improvement. Treatment specific significant increase was observed in the cocoon and shell weight with no such marked variation in the shell percentage. Notable changes were also seen in traits such as larval duration, larval weight and silk gland weight in the treated silkworm. Total protein, total carbohydrate and total lipid were analyzed in the posterior silk gland (PSG), haemolymph and fat body of fully grown larvae. The result indicated that the content of these primary metabolites varied significantly in the selected tissues depending on the time of juvenoid application. The highest content of protein in the haemolymph and silk gland was in the larvae treated at 72 h whereas the fat body protein content was lowest in the same group. The total carbohydrate was recorded lowest in the 72 h treated larvae as against the highest in the control both in haemolymph and fat body with no significant change in PSG. The total lipid content did not show any notable variation in the concentration on juvenoid administration except in the silk gland treated up to 72 h which showed a decline. The result indicates that the juvenoid induces tissue specific responses in terms of turnover in primary metabolites

Changes in the total protein, carbohydtate and lipid contents in selected tissues of silkworm, Bombyx mori L. under the influence of a juvenoid R394

Η νεανική ορμόνη R394 (ethyl 9-cyclohexyl-3,7-dimethyl-2,4-nonadienoate) εφαρμόστηκε τοπικά σε προνύμφες 5Π" σταδίου του μεταξοσκώληκα Bombyx mori L. (υβρίδιο: ΚΑ χ NB4D2) σε δόση 0,039η1/προνύμφη vta 24, 48, 72 και 96 ώρες, για την βελτίωση της παραγωγής μεταξιού. Επιλέχθηκαν τρεις κύριοι ιστοί, ο οπίσθιος μεταξογόνος αδένας (PSG). η αιμολέμφος και το λιπώδες σώμα, οι οποίοι συλλέχθηκαν από πλήρως αναπτυγμένες προ νύμφες και υπολογίστηκε η περιεκτικότητα τους σε ολικές πρωτεΐνες, ολίκούς υδατάνθρακες Kar ολικά λιπίδια. Το αποτέλεσμα έδειξε ότι η περιεκτικότητα των κύριων μεταβολιτών διέφερε σημαντικά στους παραπάνω ιστούς, ανάλογα με τον χρόνο εφαρμογής της νεανικής ορμόνης. Η υψηλότερη περιεκτικότητα σε πρωτεΐνες παρατηρήθηκε στην αιμολεμφο και το μεταξογόνο αδένα των προνυμφών που δέχτηκαν την επέμβαση για 72 ώρες, ενώ η περιεκτικότητα σε πρωτεΐνες του λιπώδους σώματος ήταν η μικρότερη στην ίδια μεταχείριση. Η χαμηλότερη ολική περιεκτικότητα σε υδατάνθρακες καταγράφηκε στις προνύμφες ποι> δέχτηκαν την επέμβαση για 72 ώρες, ενώ η υψηλότερη στον μάρτυρα τόσο στην αιμολεμφο όσο και στο λιπώδες σώμα, χωρίς να παρατηρείται σημαντική μεταβολή στον μεταξογόνο αδένα. Η ολική περιεκτικότητα σε λιπίδια δεν εμφάνισε αξιοσημείωτη παραλλακτικότητα κατά την εφαρμογή της νεανικής ορμόνης, με εξαίρεση τον μεταξογόνο αδένα σε προνύμφες που δέχτηκαν την επέμβαση για μέχρι 72 ώρες, όπου παρατηρήθηκε μείωση. Το αποτέλεσμα υποδηλώνει ότι η νεανική ορμόνη προκαλεί εξειδικευμένες για κάθε ιστό αντιδράσεις από άποψη μεταβολής της περιεκτικότητας σε κύριους μεταβολίτες, η οποία είναι ανάλογη με τις αντίστοιχες μεταβολές που παρατηρήθηκαν στο βάρος του βομβυκίου και το βάρος του κελύφους του βομβυκίου.A juvenoid. R394 (Ethyl 9-cyclohexyl-3,7-dimethyl-2,4-nonadienoate) was applied topically to 5th instar silkworm, Bombyx mori L. larvae (Hybrid: KA x NB4D2) at a dose of 0.039 nl/larva at 24, 48, 72 and 96 h, for silk yield improvement. Three major selected tissues viz., posterior silk gland (PSG), haemolymph and fat body were collected from fully-grown larvae and the total protein, total carbohydrate and total lipid contents were estimated following standard procedures. The result indicated that the content of these primary metabolites varied significantly in the selected tissues depending on the time of juvenoid application. The highest protein content was observed in the haemolymph and silk gland in the larvae treated at 72 h whereas the fat body protein content was lowest for the same treatment. The total carbohydrate was recorded lowest in the 72 h treated larvae as against the highest in the control both in haemolymph and fat body with no significant change in PSG. The total lipid content did not show any notable variation in the concentration on juvenoid administration except in the silk gland treated up to 72 h which showed a decline. The results indicate that the juvenoid induces tissue-specific responses in terms of turnover in primary metabolites which commensurates with the corresponding changes observed in the cocoon weight and cocoon shell weight

Effect of SSP – 11 on Weight and Tissue Composition of 4th Instar Larvae of Silkworm, Bombyx mori

Η αντιορμόνη νεότητας ουσία SSP-11 ((E) 4 χλωρο-α. α-τριφΟοριο-Ν [1(1Η-ιμιδαζολ-1-ύλ)-2-προπόξυ εθυλαδεν] Ο, τολονθίνη) χρησιμοποιήθηκε να προκαλέσει έκδυση προνυμφών τρίτης έκουσης από αυτες τετάρτης έκδυσης μεταξοσκώληκα, Bombyx mori (φυλή ΝΒ7). Η ουσία δόθηκε με τεχνητή τροφή για δυο ημέρες σε συγκέντρωση 200 ppm σε νεοεκδυθείσες προνύμφες 4ης ηλικίας. Το βάρος του σοόματος και των μεταξογόνων αδένων καταγραφόταν καθημερινά στην 4η ηλικία και το προφίλ των πρωτεϊνών της αιμολέμφου, του λιποίδους σώματος και των μεταξογόνων αδένιον προσδιοριζόταν στο τέλος της ηλικίας. Σε προνύμφες που δόθηκε η SSP-11 η διάρκεια διατροφής της 4ης ηλικίας επιμηκύνθηκε κατά 3-4 ημέρες και το 80-85% των προνυμφοίν άρχισαν να πλέκουν κουκούλι ως προνύμφες 3ης έκδυσης. Οκταπλάσια και τριακονταπλάσια αύξηση στα βάρη του σώματος της προνύμφης και των μεταξογόνων αδένων αντίστοιχα ήταν το αποτέλεσμα της χορήγησης SSP-11. Επιπλέον, οι συνολικές πρωτεΐνες, υδατάνθρακες, γλυκογόνο και νουκλεϊκά οξέα (DNA και RNA) αυξήθηκαν επίσης. Τα επίπεδα δραστηριότητας της αμινοτρανσφεράσης της αλανίνης και του ασπαρτικού αυξήθηκαν σημαντικά παρά στο μάρτυρα δείχνοντας αυξημένη κινητοποίηση αμινοξέων στη δραστικότητα των τρανσαμινασών. The anti-juvenoid, SSP-11 ((E) 4-chloro-a, a, a-trifluro-N [ 1 (1 H-imidazole- 1 –y1)- 2-propoxy ethylyledene] O, toludine) was used to induce trimoulters from tetramoulter larvae of the silkworm, Bombyx mori (race NB7). The compound was fed for two days through an artificial diet at the concentration of 200 ppm to newly ecdysed 4th stadium larvae. Body and silkgland fresh weight were recorded daily in the 4th larval stadium and protein profiles of haemolymph, fat body and silkgland were determined at the end of the stadium. In larvae treated with SSP-11, feeding period in stadium 4 was prolonged by 3-4 days and 80-85% of the larvae started to spin as trimoulters. Eight and thirty fold increases in the larval body and silkgland weights respectively were the result of SSP-11. Further, total proteins, total carbohydrates, glycogen and nucleic acid (DNA & RNA) also increased. The activity levels of alanine aminotransferase and aspartate aminotransferasc increased significantly than in the control indicating increased mobilization of aminoacids into transamination activities

Influence of Bakuchiol, a JH analogue from Bemchi (Psoralea corylifolia) on Silk Production in Silkworm, Bombyx mori L. (Bombycidae: Lepidoptera)

The influence of a juvenile hormone analogue (JHA), bakuchiol on the silk yield of silkworm, Bombyx mori L. was studied involving two popular commercial hybrids, KA x NB4D2 (bivoltine x bivoltine) and PM x NB4D2 (multivoltine x bivoltine). The compound was administered topically to 5th instars at 24, 48, 72 and 96 h as a single dose. Three-concentration viz., 0.625, 1.25 and 2.5 ppm were tested. Economic characters of the larvae and the resultant cocoon traits were measured. The result showed that 1.25 ppm of bakuchiol applied to 48 h old 5th instars was the most favourable treatment for improvement of commercial traits. Cocoon and cocoon shell weight and filament length have increased significantly due to this treatment. The possible role of exogenous JH analogues in eliciting this response in silkworm is discussed. Journal of Applied Sciences and Environmental Management Vol. 7(2) 2003: 31-3

PTTH - A potential growth activator in silkwonm, <i>Bombyx mori L. </i>for enhancing silk production

936-941In silkworm, prothoracicotropic hormone (PTTH), directly or indirectly controls silk production and spinning activity along with juvenile hormone (JH). An effort was made to exploit the potential of PTTH by indirectly activating silk gland for increasing silk productivity using short chain synthetic analogues of PTTH. The analogy in action was also established using PTTH extracted from the silkmoth. Different doses of 42 synthetic PTTH analogues, viz., 2.5, 5, 10 and 20 ppm and 3.3 mg/ml of PTTH extracted from silk moth heads were administered orally to V instar silkworm larvae (Race: KA×NB4D2 and PM× NB4D2) at 0-144 hr at an interval of 24 hr. The analysed data showed an improvement of about 14-23% in KA × NB4D2 and about 10-14% in PM×NB4D2 in respect of cocoon shell weight on administration of some of the synthetic PTTH analogues. The PTTH extracted from the adult brain also showed similar effect. The structural analogy of synthetic PTTHs (which improved the shell weight) with original PTTH and its probable mode of action in silkworm are discussed

Differential response of silkworm, Bombyx mori L. to phytoecdysteroid depending on the time of administration

The differential response of silkworm, Bombyx mori   L. to phytoecdysteroid when administered at different ages of 5th instar was studied on a popular Chinese silkworm hybrid, Xinhang x Keming reared on the 'Hu Sang 197' variety of mulberry leaves. Phytoecdysteroid, a chlolest -7 ene- 6- one- carbon skeleton (C27) from a plant source, Radyx achyranthes   was administered to 5th instar silkworm per os at a rate of 2 μm per larva to different batches of silkworm at 48 h, 72 h and at the onset of cocoon spinning when a few larvae were ripe. The larval duration, larval mounting duration, cocoon characters and reeling traits were influenced by phytoecdysteroid. The intensity of influence was dependent on the time of application. The larvae treated at 48 h improved almost all economic traits significantly with a marginal increase in larval duration. In the larvae treated at 72 h, the economic traits were adversely affected but the larval duration was shortened by about 24 hours. In the larvae treated at the onset of cocoon spinning, the mounting duration was substantially reduced without much affect on the cocoon traits which would be a big benefit in commercial sericulture. The physiological significance of varied response of silkworm to phytoecdysteroid administration is discussed. @JASE

Hormetic influence on silkworm, bombyx mori L., of the phytojuvenoid ω-formyl longifolene oxime propargyl ether

The hormetic influence on silkworm, Bombyx mori L. (Lepidoptera; Bombycidae) of the juvenile hormone mimic ω-formyl longifolene oxime propargyl ether (NL13) was assayed. Emulsions containing 2.5, 5.0 and 10.0 ppm of the compound were administered topically as a single dose, to two popular commercial silkworm hybrids, viz. KA × NB4D2 and PM × NB4D2, at 24, 48, 72 and 96 h into the 5th instar, and economic characters of the larvae and resultant cocoons measured. A medium and absolute control were maintained in parallel. It was found that administration of 5 ppm of NL13 to 48-h-old 5th instars resulted in the maximum improvement in commercial traits. The possible role of exogenous JH-like compounds in eliciting this response in silkworm is discussed