Algesia and local responses induced by neurokinin A and substance P in human skin and temporal muscle

Neurokinin A (NKA), substance P (SP) and the two peptides combined (SP + NKA) were injected intracutaneously on the forearm and into the temporal muscle of healthy volunteers. Pain intensity, cutaneous wheal and flare responses and tenderness of the temporal muscle were quantitated. SP but not NKA induced cutaneous pain. This relates the algesic effect of SP to the specific N-terminal amino acid sequence of the peptide, not shared by NKA. NKA, however, potentiated the algesic effect of SP as SP + NKA induced a significantly prolonged cutaneous pain sensation. Both peptides induced wheals, but only SP induced flare. These results confirm previous studies relating wheal formation to the identical C-terminal amino acid sequence of the two peptides and flare reaction to the N-terminal part of SP. Injections into the temporal muscle did not cause pain or tenderness.     

Somatic characteristics of an Australian population of Oreochromis mossambicus (Pisces: Cichlidae)

Synopsis The Oreochromis mossambicus population of North Pine Dam, Brisbane, Queensland, Australia was studied over three years, from 1985 to 1988. Basic somatic data were obtained and characteristic values of condition factor, sex ratio, gonosomatic index and the relationships between total and standard lengths, and length and weight, were calculated. Standard length is proportional to total length by the formula SL = –0.321 + 0.799 TL. Weight is related to length by the isometric formula W = aL³. Condition factor values spanned the range 0.0254 to 0.0563, with an average of 0.04078 for males and 0.03877 for females. The sex ratio is 1: 1 until maturity is reached (21 cm SL), at which time the catch rate of the sexes varies due to divergent habitat selection behaviour. Average values of gonosomatic index, considered in relation to maturity classification, are similar to those obtained from other populations, however maximum values are generally much lower, at 0.47 for males and 3.62 for females. These characteristic values are compared, with varying degrees of concordance, with those for populations of this species in other countries.     

Voltage dependence of Na/K pump current inXenopus oocytes

Summary Stage V and VI (Dumont, J.N., 1972.J. Morphol. 136:153–180) oocytes ofXenopus laevis were treated with collagenase to remove follicular cells and were placed in K-free solution for 2 to 4 days to elevate internal [Na]. Na/K pump activity was studied by restoring the eggs to normal 3mm K Barth's solution and measuring membrane current-voltage (I–V) relationships before and after the addition of 10 m dihydroouabain (DHO) using a two-microelectrode voltage clamp. Two pulse protocols were used to measure membraneI–V relationships, both allowing membrane currents to be determined twice at each of a series of membrane potentials: (i) a down-up-down sequence of 5 mV, 1-sec stair steps and (ii) a similar sequence of 1-sec voltage pulses but with consecutive pulses separated by 4-sec recovery periods at the holding potential (–40 mV). The resulting membraneI–V relationships determined both before and during exposure to DHO showed significant hysteresis between the first and second current measurements at each voltage. DHO difference curves also usually showed hysteresis indicating that DHO caused a change in a component of current that varied with time. Since, by definition, the steady-state Na/K pumpI–V relationship must be free of hysteresis, the presence of hysteresis in DHO differenceI–V curves can be used as a criterion for excluding such data from consideration as a valid measure of the Na/K pumpI–V relationship. DHO differenceI–V relationships that did not show hysteresis were sigmoid functions of membrane potential when measured in normal (90mm) external Na solution. The Na/K pump current magnitude saturated near 0 mV at a value of 1.0–1.5 A cm^–2, without evidence of negative slope conductance for potentials up to +55 mV. The Na/K pump current magnitude in Na-free external solution was approximately voltage independent. Since these forward-going Na/K pumpI–V relationships do not show a region of negative slope over the voltage range –110 to +55 mV, it is not necessary to postulate the existence of more than one voltage-dependent step in the reaction cycle of the forward-going Na/K pump.     

Carbohydrates,lipids and lipoproteins and islet changes in diabetes with superimposed myocardial infarction

Short-term metabolic and concomitant morphologic effects of streptozotocin diabetes on isoproterenol-induced myocardial infarction was studied in Wistar rats, Of particular significance was the observation that myocardial infarction in concert with diabetes brought about a distinctive exacerbation of the severity and complexity of the histopathological lesions. Of all the biochemical parameters, serum glucose and free fatty acids registered maximum elevation and serum lactate and cardiac glycogen levels a maximum reduction. Among the lipoproteins, an inverse relationship was found between high density lipoproteins and low density and very low density lipoproteins; while high density lipoproteins, ratio of high density lipoprotein to low density lipoprotein and the percentage of high density lipoprotein were decreased, there was a significant increase in low density lipoprotein concentration and percentage values of low density and very low density lipoproteins. In diabetes, the B cell of the endocrine pancreas depicted selective necrosis. Loss of insulin granules and wide-spread necrobiosis of cellular elements of the pancreatic islets were observed, respectively, in myocardial infarction and in diabetes plus myocardial infarction combinations. Pathological evidence of chemical-induced mild toxicity was present in the exocrine parenchyma. Mitotic features and the presence of centroacinar cells in the damaged Langerhans’ islets supposedly formed the basis of regeneration of the tissue in diabetes, with or without vascular complications     

Regulation of the loss of frost hardiness in Pinus radiata by photoperiod and temperature

Abstract. In controlled environments, the interactive effects of warm (16: 8°C, day: night) and cool (12: 4°C, day: night) temperatures and long (13.5 h) and short (10 h) photoperiods on the dehardening of seedlings of Pinus radiata D. Don were investigated. In another experiment, the effect of four photoperiods from 9 to 14 h was examined. In a third, dehardening at constant temperatures from 5 to 17°C was followed. There was no evidence for an interaction between photoperiod and temperature. Dehardening was temporarily delayed by photoperiods below about 10 h, but there was no other quantitative effect of photoperiod. At constant temperatures, the rate of dehardening was initially constant but declined as the minimum summer frost hardiness was reached. In the initial phase the rate of dehardening was a linear function of temperature, increasing from 0.05°C day⁻¹ at 8°C to 0.30 °C day⁻¹ at 17°C. Temperature controlled the loss of frost hardiness by regulating the rate of dehardening.     

Risk of predation,hydrodynamic efficiency and their influence on school structure

Synopsis Laboratory studies were conducted on 15 schools of blackchin shiners, Notropis heterodon, to determine if they altered their structure in response to changing environmental demands. The hypothesis tested was that fish schools should sacrifice a flat, hydrodynamically efficient structure in favour of an unobstructed visual field in the presence of a predator by staggering in the vertical plane. Ten schools were exposed for two weeks to a simple environment with only a current. For the next two-week period a predator was added. Five control schools were exposed to the simple environment for both two-week periods. Six of the ten treated schools increased their staggering in the vertical dimension as predicted while none of the control schools changed. This result was suggestive that hydrodynamic advantages were sacrificed. Respirometer experiments indicated these fish were capable of achieving some hydrodynamic benefits from schooling but these benefits may be a function of fish size.     

Molecular basis for the special properties of proteins and enzymes from Halobacterium marismortui

Abstract Three proteins from Halobacterium marismortui , malate dehydrogenase (hMDH), glutamate dehydrogenase (hGDH) and ferredoxin (hFD) were purified and characterized with respect to their molecular masses, amino acid composition and, for hFD only, primary structure. Striking features of halophilic proteins are: the high excess of acidic over basic residues; acidic clusters in the sequence. Low-salt concentration causes inactivation and changes in structural parameters of hMDH and hGDH. Reactivation of hMDH involves long-lived stable intermediates. The salt concentration optimum of enzymic activity is independent of salt nature. The high capacity of halophilic proteins to retain water and salt is due to unique molecular properties, studied by physico-chemical techniques.     

Synthesis of polypeptides by microwave heating II. Function of polypeptides synthesized during repeated hydration-dehydration cycles

Summary Polypeptides, synthesized from a mixture of amino acid amides by microwave heating during repeated hydration-dehydration cycles, showed hydrolase- and oxidoreductase-like catalytic activities. Poly(GAVDH), polypeptides synthesized from an equimolar mixture (each 0.1 M) of glycinamide,l-alaninamide,l-valinamide,l-aspartic acid -amide, andl-histidinamide, catalyzed the hydrolysis of PNPAc. The hydrolytic rate of PNPAc with poly(GAVDH) was the quadruple of that ofl-histidine alone. Though the k_cat values of different resulting polypeptides were 10³–10⁶ times less than those of native hydrolases, the K_m value of the polypeptides further containing phenylalanine residues was nearly equal to that of the esterase. This result indicates the presence of hydrophobic interaction between a substrate and the polypeptides. Resulting polypeptides also showed catalytic activity for the reduction of ferricyanide ion [Fe(CN)^3–] with NADH. The polypeptides seemed to have a strong affinity for adenine nucleotides, because the reaction was inhibited by adenine derivatives such as NAD⁺ and AppA. A hypothesis for the emergence of primitive protein enzymes is discussed.     

Initiation and solicitation in male-female grooming in a wild Japanese macaque troop on yakushima island

Grooming initiation among adult males and females of a Japanese macaque troop was analyzed during the non-mating season. Some gestures (“solicitation”) elicited grooming from partners at a high rate. Grooming initiation patterns were divided into two main types: (1) a male often solicited a female to groom him immediately after approaching her and was groomed by her; and (2) a female approached an alpha male selectively, and immediately groomed him. After a female groomed a male, she rarely solicited him to groom her and instead often moved away from him. These results indicated that males were motivated to be groomed, while females were more highly motivated to groom. Sex differences in grooming motivation can be explained by sex differences in the benefit to be groomed.