Coeloconic sensilla on the antennae of the yellow fever mosquito,Aedes aegypti (L.)

Zusammenfassung Elektronenoptischer Nachweis von Sensilla coeloconica beiAedes aegypti-«Weibchen» was beweist, dass nicht nur Culicinae, sondern auch Anophelinae Sinnesstrukturen besitzen.

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Supported by Medical Research Council Grant No. MA 2909.     

Ein neuer Sensillentyp auf den Antennen weiblicher Moskitos (Aedes aegypti L.)

Summary A new type of thin-walled, hair-like setae was found on the antennae of the female mosquito. The length of the 3 different types, already described in the literature, is compared with the author's own measurements. This new type differs not only in length but in electrophysiological responses.     

The potency of male accessory gland material in the mosquito (Aedes aegypti)

Summary Injections of male accessory gland material fromAedes aegypti into the hemocoeles of virgin female mosquitoes indicate that the potency of the secretion is equivalent to the amount of semen which a male normally places within the female. This estimation is far less than had been previously calculated. It is suggested that the termmatrone for male accessory gland material is inappropriate since it does not convert a maid into a matron but prevents reinsemination of an impregnated female.Scientific Article No. A2098, Contribution No. 5054 of the Maryland Agricultural Experiment Station.     

Non-specific esterases in females ofAedes aegypti (L.)

Zusammenfassung Unspezifische Esterasen wurden während des Adultlebens vonAedes aegypti (L.) quantitativ bestimmt und zwischen Weibchen von 2 Stämmen verglichen. Alterungist begleitet von einer Zunahme der Bänderzahl und einer Abnahme der Esterasenaktivität pro Weibchen; die relative Aktivität der einzelnen Esterasen-Isozyme bleibt aber mehr oder weniger konstant. Nach einem Blutmahl, dem Beginn eines neuen gonotrophen Zyklus, wurden auffällige Veränderungen im Bändermuster festgestellt. 4 Tage später, nach erfolgter Eiablage, ist dieses Muster wieder ähnlich wie vor der Blutaufnahme.     

Effects of cerebral lateral,ventricular infusions of phloridzin on feeding and body weight in Gallus domesticus (L.)

Summary Contrary to earlier findings in rats, cerebral lateral ventricular infusions of 1×10^–3 M or 2×10^–3 M solutions of phloridzin at a rate of 2.5 l/min for 90 min had no significant stimulating effects on food intake and weight gain in hens and cocks. These different responses to intraventricular phloridzin might reflect a difference of sensitivity to the inhibitory action of phloridzin on glucose transport in cerebral cells or certain peculiarities of mechanisms controlling food intake in chickens.     

Biological markers in feeding experiments of mosquito larvae (Culex (Lutzia) raptor)

Zusammenfassung Die in Laborzuchten kannibalistischen Larven der MückeCulex (Lutzia) raptor ernähren sich bei freier Wahl von Larven anderer Mückenarten (Präferenzfolge:Aedes aegypti, Anopheles stephensi, Culex fatigans). Versuche mit einer gelben Mutante vonC. fatigans zeigen, dassA. aegypti wegen ihrer gelben Naturfarbe allen anderen Arten vorgezogen wird. Auch die Bewegungsintensität der Larven scheint eine Rolle zu spielen.     

Structural diversity of trypsin from different mosquito species feeding on vertebrate blood

Mosquito trypsin was purified using a combination of ion exchange and affinity chromatography with the ligand soybean trypsin inhibitor. Three Aedes and three Anopheles species were tested, all of which are specialized in the digestion of vertebrate blood. Amino-terminal sequences of HPLC-purified trypsins from Aedes aegypti and Anopheles quadrimaculatus revealed homologies of 30-40% with vertebrate and other invertebrate proteases previously identified as serine-proteases. The purified mosquito trypsins have molecular masses between 25 kDa and 36 kDa, as determined by denaturing polyacrylamide electrophoresis, and are heterogeneous in size and number in the various species. The number of SDS-bands varies between 3 and 6 in Aedes and between 1 and 3 in Anopheles. The specific activities, determined with the substrate TAME, range from 240 U/mg in Aedes aegypti to 1065 U/mg in Anopheles quadrimaculatus. All mosquito trypsins tested have acidic isoelectric points between pH 3.5 and pH 5.4. No alkaline proteases were detected. Polyclonal antisera against Aedes aegypti and Anopheles albimanus trypsin do not cross-react with bovine trypsin. Cross-reactivity of the two sera with trypsin from six mosquito species suggests the presence of at least 2 enzyme families.     

Structural diversity of trypsin from different mosquito species feeding on vertebrate blood

Summary Mosquito trypsin was purified using a combination of ion exchange and affinity chromatography with the ligand soybean trypsin inhibitor. ThreeAedes and threeAnopheles species were tested, all of which are specialized in the digestion of vertebrate blood. Amino-terminal sequences of HPLC-purified trypsins fromAedes aegypti andAnopheles quadrimaculatus revealed homologies of 30–40% with vertebrate and other invertebrate proteases previously identified as serine-proteases. The purified mosquito trypsins have molecular masses between 25 kDa and 36 kDa, as determined by denaturing polyacrylamide electrophoresis, and are heterogeneous in size and number in the various species. The number of SDS-bands varies between 3 and 6 inAedes and between 1 and 3 inAnopheles. The specific activities, determined with the substrate TAME, range from 240 U/mg inAedes aegypti to 1065 U/mg inAnopheles quadrimaculatus. All mosquito trypsins tested have acidic isoelectric points between pH 3.5 and pH 5.4. No alkaline proteases were detected. Polyclonal antisera againstAedes aegypti andAnopheles albimanus trypsin do not cross-react with bovine trypsin. Cross-reactivity of the two sera with trypsin from six mosquito species suggests the presence of at least 2 enzyme families.     

Effect of fluoride on in vivo nitrate reduction in rice leaves (Oryza sativa L.)

Summary Fluoride had no effect on in vitro nitrate reductase activity in rice leaves, but in vivo activity was strongly inhibited. It is suggested that fluoride brings about this inhibition by adversely affecting the physiological NADH generating system required for in vivo nitrate reduction.Acknowledgments. We thank Dr M.S. Naik for useful suggestions and discussion. C.S.R. is grateful to Indian Council of Agricultural Research for a Senior Research Fellowship.     

Suppression of pupal esterase activity in Aedes aegypti (Diptera: Culicidae) by an insect growth regulator.

Changes in non-specific esterases of Aedes aegypti were noted during pupal development. One esterase band was found to increase markedly within 3 h of pupation and this increase in activity was suppressed by prior treatment of larvae with an insect growth regulator, ZR 515. It is suggested that the esterase activity may help to reduce endogenous levels of juvenile hormone during metamorphosis and that the growth regulator may prevent this normal regulation.     

Effect of certain environmental factors on the cerebral neurosecretory cells of American cockroachPeriplaneta americana (L.)

Summary Under illumination, the cerebral neurosecretory cells (NSC) ofPeriplaneta americana were found to be depleted of neurosecretory material (NSM). It is suggested that, due to prolonged exposure to illumination, the synthesis of NSM was checked. The NSC were found densely packed with NSM after keeping the insects in total darkness. Clumping of NSC and their axons was brought about by 15 days of starvation. Diet played no significant role in the neurosecretory activity.We are thankful to Mr Fakhruddin, Saifia Educational Society for providing research facilities.     

Effect of toxic and non-toxic sugars on motility of honey bee (Apis mellifera L.) spermatozoa

Zusammenfassung Die Motilität der Spermien bei der HonigbieneApis mellifera L. wird in vitro furch die Monosaccharide Glukose, Fruktose und Galaktose, die Dissacharide Maltose, Melibiose und Trehalose, sowie das Trisaccharid Melezitose ausgelöst. Mamose Rhamnose und Raffinose hingegen sind unwirksam. Von den wirksamen Zuckern sind Galaktose und Melibiose für Bienen giftig.