scholarly journals Nitrogen Metabolism in the American Cockroach: An Examination of Whole Body and Fat Body Regulation of Cations in Response to Nitrogen Balance

1974 ◽  
Vol 61 (3) ◽  
pp. 557-570 ◽  
Author(s):  
DONALD E. MULLINS ◽  
DONALD G. COCHRAN

The effects of nitrogen balance on uric acid/urate, K+ and Na+ storage or mobilization were examined in the American cockroach Periplaneta americana (L.). Cockroaches on a high nitrogen diet increased in whole body uric acid/urates, K+ and Na+. Those on a semi-starvation diet maintained fairly constant levels of uric acid/urates, K+ and Na+. However, those on a low nitrogen diet mobilized stored uric acid/urates and K+, but not Na+. Analyses for uric/urates K+, Na+, Ca2+ and Mg2+ in fat body tissue from insects maintained on 12 diets containing different concentrations and sources of dietary nitrogen showed that only K+ concentration could be correlated with fat body uric acid/urate storage. Whole body storage and mobilization of uric acid/urates, K+ and Na+ were reflected in the faecal/dietary ratios of K+ and Na+. A model for a uric acid/urate ion sink which might be associated with ionic and osmotic balances is proposed, and some evidence for its existence is discussed.

1974 ◽  
Vol 61 (3) ◽  
pp. 541-556
Author(s):  
DONALD E. MULLINS

The effects of dietary nitrogen levels in relation to ammonotelism, cation excretion and water requirements were examined in the American cockroach, Periplaneta americana (L.). Very little ammonia is released from the respiratory surfaces; rather it appears to be eliminated in the faeces, presumably as ammonium ions. Microflora present in the hindgut may contribute significantly to the production of excreted ammonia under certain dietary conditions. Injections of buffers containing either NH4+, K+ or Na+ resulted in normal (NH4+ and K+), or less than normal (Na+) levels of ammonia excretion. Faeces collected from cockroaches maintained on twelve different diets containing various levels and sources of nitrogen were examined for NH4+, K+, Na+, Ca2+ and Mg2+. Ammonium ions were found to be the major cations contained in the faeces and were excreted in increasing amounts as the dietary nitrogen levels increased. The ad libitum water requirements were closely correlated with dietary nitrogen levels, and subsequently with ammonia excretion. Certain aspects concerning the possible factors involved, and the significance of ammonia excretion, are discussed.


1956 ◽  
Vol 34 (1) ◽  
pp. 68-74 ◽  
Author(s):  
Ann D. Anderson ◽  
Ralph B. March

Carbonic anhydrase activity has been demonstrated in vitro in preparations of the head, fat body, and gut of the American cockroach, Periplaneta americana (L.), and in the adult housefly, Musca domestica L. The insect factor, which is soluble in aqueous media and can be separated from the particulate cell fragments of insect tissue homogenates is heat labile and sensitive to cyanide inactivation. It is strongly inhibited by sulphanilamide, p-aminoethylphenyl-sulphonamide, and p-chlorphenylsulphonamide. No inhibition has been found with N-substituted sulphonamides or with any of the organic insecticides examined, including DDT, lindane, dieldrin, nicotine, rotenone, pyrethrins, and para-oxon. Sensitivity of carbonic anhydrase to sulphonamides having an intact—SO2NH2 group is also characteristic of mammalian preparations. The data indicate that inhibition of insect carbonic anhydrase cannot be an important factor in the mode of action of DDT or other organic insecticides.


1990 ◽  
Vol 269 (2) ◽  
pp. 309-313 ◽  
Author(s):  
G Gäde ◽  
H Wilps ◽  
R Kellner

A hypertrehalosaemic neuropeptide from the corpora cardiaca of the blowfly Phormia terraenovae has been isolated by reversed-phase h.p.l.c., and its primary structure was determined by pulsed-liquid phase sequencing employing Edman chemistry after enzymically deblocking the N-terminal pyroglutamate residue. The C-terminus was also blocked, as indicated by the lack of digestion when the peptide was incubated with carboxypeptidase A. The octapeptide has the sequence pGlu-Leu-Thr-Phe-Ser-Pro-Asp-Trp-NH2 and is clearly defined as a novel member of the RPCH/AKH (red-pigment-concentrating hormone/adipokinetic hormone) family of peptides. It is the first charged member of this family to be found. The synthetic peptide causes an increase in the haemolymph carbohydrate concentration in a dose-dependent fashion in blowflies and therefore is named ‘Phormia terraenovae hypertrehalosaemic hormone’ (Pht-HrTH). In addition, receptors in the fat-body of the American cockroach (Periplaneta americana) recognize the peptide, resulting in carbohydrate elevation in the blood. However, fat-body receptors of the migratory locust (Locusta migratoria) do not recognize this charged molecule, and thus no lipid mobilization is observed in this species.


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