Control Larvae (control + larva)

Distribution by Scientific Domains


Selected Abstracts


Evidence for RPE65-independent vision in the cone-dominated zebrafish retina

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 7 2007
Helia B. Schonthaler
Abstract An enzyme-based cyclic pathway for trans to cis isomerization of the chromophore of visual pigments (11- cis -retinal) is intrinsic to vertebrate cone and rod vision. This process, called the visual cycle, is mostly characterized in rod-dominated retinas and essentially depends on RPE65, an all- trans to 11- cis -retinoid isomerase. Here we analysed the role of RPE65 in zebrafish, a species with a cone-dominated retina. We cloned zebrafish RPE65 and showed that its expression coincided with photoreceptor development. Targeted gene knockdown of RPE65 resulted in morphologically altered rod outer segments and overall reduced 11- cis -retinal levels. Cone vision of RPE65-deficient larvae remained functional as demonstrated by behavioural tests and by metabolite profiling for retinoids. Furthermore, all- trans retinylamine, a potent inhibitor of the rod visual cycle, reduced 11- cis -retinal levels of control larvae to a similar extent but showed no additive effects in RPE65-deficient larvae. Thus, our study of zebrafish provides in vivo evidence for the existence of an RPE65-independent pathway for the regeneration of 11- cis -retinal for cone vision. [source]


Immulectin-4 from the tobacco hornworm Manduca sexta binds to lipopolysaccharide and lipoteichoic acid

INSECT MOLECULAR BIOLOGY, Issue 2 2006
X.-Q. Yu
Abstract Insect C-type lectins function as pattern recognition receptors in innate immunity. In the tobacco hornworm Manduca sexta, we have previously isolated three C-type lectins named immulectins, which are involved in innate immune responses. Here, we report a new member of the immulectin family, immulectin-4 (IML-4). IML-4 mRNA was detected in the fat body of control larvae and was induced in the fat body when larvae were injected with bacteria. Recombinant IML-4 bound to bacterial lipopolysaccharide (LPS) and lipoteichoic acid (LTA), and the binding activity was not affected by addition of calcium or EGTA. IML-4 agglutinated bacteria and yeast, and agglutination of Escherichia coli by IML-4 was concentration- and calcium-dependent. IML-4 also enhanced haemocyte encapsulation and melanization. [source]


BIOACTIVITIES AND MECHANISM OF SPIRO ENOL ETHER ANALOGUES AGAINST PIERIS RAPAE

INSECT SCIENCE, Issue 1 2004
Zhi-xiang Zhang
Abstract, Nineteen kinds of spiro enol ether analogues were screened with larvae of Pieris rapae for antifeedant activity. The results showed that the antifeedant activity of compounds No.20 and No. 12 was higher than others. In non-choice test, AFC50 values within 24 h of compounds No.20 and No. 12 against 3rd instar larvae of P. rapae were 226.93 ,g/mL and 370.00 ,g/mL, and that in choice test against 4th larvae were 280.54 ,g/mL and 398.88 ,g/mL, respectively. Compd. No.20 could prolong the eggs hatch time and reduce the haemolymph content and the protein content in haemolymph of 4th instar larvae obviously. Compd. No.20 could protect tested leaves and control larvae of P. rapae effectively. [source]


Growth and survival of river catfish Mystus nemurus (Cuvier & Valenciennes) larvae fed isocaloric diets with different protein levels during weaning

JOURNAL OF APPLIED ICHTHYOLOGY, Issue 3 2000
R. V. Eguia
Summary The growth of river catfish Mystus nemurus (Cuvier & Valenciennes) larvae fed four isocaloric diets (4200 kcal kg,1) with different protein levels during weaning was determined. Diets containing 45, 50, 55, and 60% protein were formulated by linear programming using amino acid profiles based on that of 2-day-old river catfish larvae. Artificial diets were fed to the larvae beginning at day 5 after being initially fed Artemia nauplii for 4 days. The larvae thrived solely on artificial diets from day 8 to day 16. On the other hand, the control larvae were fed Artemia nauplii from day 1 to day 16. Results of the feeding trial showed that growth and survival of M. nemurus larvae given the diet containing 60% protein were high and comparable to those of the larvae given only live food (control). Larvae fed the 55% protein diet had significantly lower growth and survival than the larvae on the control and 60% diets but significantly higher growth and survival rates than did larvae fed with 45 and 50% protein diets. Carcass moisture and total lipids after 16 days of feeding did not differ significantly (P > 0.05), but body protein increased with increasing dietary protein. Body protein of the control larvae was similar to that of larvae given the 60% protein diet. [source]


cDNA cloning and induction of tyrosine hydroxylase gene from the diamondback moth, Plutella xylostella

ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 2 2010
Se Hui Hwang
Abstract We cloned a full-length tyrosine hydroxylase cDNA from the integument of the diamondback moth, Plutella xylostella. In the phylogenetic tree, tyrosine hydroxylase (PxTH) clustered with the other lepidopteran THs. Serine residues in the PxTH sequence, namely Ser24, Ser31, Ser35, Ser53, and Ser65, were predicted to be the target sites for phosphorylation based on PROSITE analysis. In particular, Ser35 of PxTH is highly conserved across a broad phylogenetic range of animal taxa including rat and human. Western blot analysis using both PxTH-Ab1 and PxTH-Ab2 polyclonal antibodies verified the expression of PxTH in all life cycle stages of P. xylostella, namely the larval, pupal, and adult stages. To examine the possible immune function of PxTH in P. xylostella, PxTH gene expression was investigated by RT-PCR and western blotting analysis after challenging P. xylostella with bacteria. PxTH expression was elevated 1,h post-infection and was continued till 12,h of post-infection relative to control larvae injected with sterile water. © 2010 Wiley Periodicals, Inc. [source]


Host-mediated induction of ,-amylases by larvae of the Mexican bean weevil Zabrotes subfasciatus (Coleoptera: Chrysomelidae: Bruchinae) is irreversible and observed from the initiation of the feeding period

ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 4 2010
Thaís D. Bifano
Abstract Larvae of Zabrotes subfasciatus secrete , -amylases that are insensitive to the , -amylase inhibitor found in seeds of Phaseolus vulgaris. By analyzing amylase activities during larval development on P. vulgaris, we detected activity of the constitutive amylase and the two inducible amylase isoforms at all stages. When larvae were transferred from the non , -amylase inhibitor containing seeds of Vigna unguiculata to P. vulgaris, the inducible , -amylases were expressed at the same level as in control larvae fed on P. vulgaris. Interestingly, when larvae were transferred from seeds of P. vulgaris to those of V. unguiculata, inducible , -amylases continued to be expressed at a level similar to that found in control larvae fed P. vulgaris continuously. When 10-day-old larvae were removed from seeds of V. unguiculata and transferred into capsules containing flour of P. vulgaris cotyledons, and thus maintained until completing 17 days (age when the larvae stopped feeding), we could detect higher activity of the inducible , -amylases. However, when larvae of the same age were transferred from P. vulgaris into capsules containing flour of V. unguiculata, the inducible , -amylases remained up-regulated. These results suggest that the larvae of Z. subfasciatus have the ability to induce insensitive amylases early in their development. A short period of feeding on P. vulgaris cotyledon flour was sufficient to irreversibly induce the inducible , -amylase isoforms. Incubations of brush border membrane vesicles with the , -amylase inhibitor 1 from P. vulgaris suggest that the inhibitor is recognized by putative receptors found in the midgut microvillar membranes. © 2010 Wiley Periodicals, Inc. [source]


Adenanthera pavonina trypsin inhibitor retard growth of Anagasta kuehniella (Lepidoptera: Pyralidae)

ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 4 2010
Maria Lígia Rodrigues Macedo
Abstract Anagasta kuehniella is a polyphagous pest that feeds on a wide variety of stored products. The possible roles suggested for seed proteinase inhibitors include the function as a part of the plant defensive system against pest via inhibition of their proteolytic enzymes. In this study, a trypsin inhibitor (ApTI) was purified from Adenanthera pavonina seed and was tested for insect growth regulatory effect. The chronic ingestion of ApTI did result in a significant reduction in larval survival and weight. Larval and pupal developmental time of larvae fed on ApTI diet at 1% was significantly longer; the larval period was extended by 5 days and pupal period was 10 days longer, therefore delaying by up to 20 days and resulting in a prolonged period of development from larva to adult. As a result, the ApTI diet emergence rate was only 28% while the emergence rate of control larvae was 80%. The percentage of surviving adults (%S) decreased to 62%. The fourth instar larvae reared on a diet containing 1% ApTI showed a decrease in tryptic activity of gut and that no novel proteolytic form resistant to ApTI was induced. In addition, the tryptic activity in ApTI -fed larvae was sensitive to ApTI. These results suggest that ApTI have a potential antimetabolic effect when ingested by A. kuehniella. © 2010 Wiley Periodicals, Inc. [source]


Eicosanoids influence in vitro elongation of plasmatocytes from the tobacco hornworm, Manduca sexta

ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 1 2005
Jon S. Miller
Abstract Nodule formation is the predominant insect cellular defense reaction to bacterial challenges, responsible for clearing the largest proportion of infecting bacteria from hemolymph circulation. Hemocyte spreading behavior is a critical step in the nodulation process. It has been suggested that eicosanoids mediate several steps in the process. However, the influence of eicosanoids on hemocyte spreading has not been investigated in detail. To test the hypothesis that eicosanoids mediate hemocyte spreading behavior, I treated larvae of the tobacco hornworm, Manduca sexta, with eicosanoid biosynthesis inhibitors and later assessed plasmatocyte elongation on glass slides. Plasmatocytes from larvae treated with dexamethasone did not elongate to the extent of plasmatocytes from untreated control larvae. The dexamethasone effect on plasmatocyte elongation was expressed in a dose-dependent manner and was reversed by injecting dexamethasone-treated larvae with the eicosanoid-precursor fatty acid, arachidonic acid. Palmitic acid, which is not substrate for eicosanoid biosynthesis, did not reverse the influence of dexamethasone on plasmatocyte elongation. Finally, plasmatocytes from larvae treated with a range of eicosanoid biosynthesis inhibitors did not elongate to the extent of plasmatocytes from control larvae. Plasmatocyte width did not appear to be influenced in this study. These findings strongly support the idea that insect plasmatocyte elongation is influenced by eicosanoids. Arch. Insect Biochem. Physiol. 59:42,51, 2005. © 2005 Wiley-Liss, Inc. [source]