bluuebunny/crossref_metadata_2025 huggingface dataset:
Motor Pattern of the Stinging Response in the Honeybee APIS Mellifera
Authors: Ogawa H. , Kawakami Z. , Yamaguchi T.
Published: April 2021

In the stinging response of the worker honeybee (Apis mellifera), rhythmic movements of the lancets on the stylet are produced by alternating contractions of a set of stinging muscles (a protractor, M198, and a retractor, M199) on each side during co-contraction of the frucula muscles (M197s) on both sides. In this study, stinging movements were elicited by tactile stimulation to the sternum in isolated abdomens, in intact animals and in preparations in which the connectives between the sixth and terminal abdominal ganglia were cut. There was a close relationship among the following three temporal variables of stinging motoneurone pattern: the interval between successive bursts of a stinging muscle, the duration of a burst and the time lag between the bursts of homologous stinging muscles on both sides. All of these variables increased linearly as the sting was inserted deeper into a soft object and the tension on the lancets increased.

When sensory nerves from the proprioceptors (campaniform sensilla on the tapering sting shaft and hair plates at the basal cuticular plate) were cut on both sides, the relative timing of bursts of homologous stinging muscles on both sides and antagonistic stinging muscles on each side became more variable. When a proprioceptive input was removed from one side during penetration of the sting, the frequency of the bursts of stinging muscles was higher and the duration of bursts was shorter on the cut side than on the intact side; nevertheless, a sting muscle was still activated out of phase with its antagonistic muscle on the ipsilateral side and its homologous muscle on the contralateral side.

These results suggest that the motor pattern driving the rhythmic movements of stinging muscles is produced by a central pattern generator consisting of a pair of oscillators located in the terminal abdominal ganglion and that the precise timing of the motor pattern in a hemiganglion is controlled mainly by proprioceptive inputs on its own side.
Electrophysiology of K+ Transport by Midgut Epithelium of Lepidopteran Insect Larvae:III. Goblet Valve PATENCY
Authors: Moffett David F. , Koch Alan , Woods Robin
Published: April 2021

The midgut epithelium of lepidopteran insect larvae contains characteristic goblet cells possessing an apical cavity surrounded by goblet cell apical membrane (GCAM) and guarded from the gut lumen by a valve-like structure. The currently accepted model of active K+ secretion by the midgut of lepidopteran insect larvae locates the major active step at the GCAM, implying that actively transported K+ reaches the gut lumen by passing through the valve.

The major question for these studies was whether K+ could pass through the valve by diffusion in free solution. Using tetramethylammonium (TMA+) as a surrogate for K+, and exploiting the high sensitivity of standard K+-selective ion-exchange resin to quaternary amines, we used K+-selective intracellular electrodes to measure the rate of access of apically applied TMA+ to the goblet cavity.

TMA+ failed to gain access to more than half of the cavities. For those cavities to which it did gain access, the influx and efflux rates and predicted equilibrium concentrations of TMA+ were too low to be consistent with diffusive exit of transported K+ along the same path. Upon superfusion with cytochalasin E, a disrupter of actin-based cytoskeleton, the TMA+ influx rates immediately increased for those cavities previously accessible to TMA+, but not for those previously inaccessible. Increases in TMA+ influx suggestive of spontaneous valve opening were not observed. The results are consistent with an indirect route of access of TMA+ to goblet cavities.

We conclude that goblet valves are closed in vitro. Assuming that the goblet cavity is part of the transport route, actively transported K+ must exit the cavity to the gut lumen by a mechanism that does not involve diffusion in free solution.
Electrophysiology of K+ Transport by Midgut Epithelium of Lepidopteran Insect Larvae : IV. A Multicompartment Model Accounts for Tetramethylammonium Entry into Goblet Cavities
Authors: Koch Alan , Moffett David F.
Published: April 2021

A quantitative model was developed to explain the kinetics of tetramethylammonium (TMA+) movement into and out of the goblet cavities of posterior midgut cells of Manduca sexta based on the data of the accompanying paper, which indicated that TMA+ does not enter the goblet cavity directly from the lumen.

The model has two cellular compartments between the lumen and goblet cavity; these have been tentatively identified as the columnar cell and goblet cell cytoplasm. Five transmembrane pathways are included: from lumen to columnar cell, from columnar cell to goblet cell, from goblet cell cytoplasm to goblet cell cavity, and across the basal membrane of each cell type. These pathways need not be channels; they could use endocytotic or exocytotic mechanisms or, in the case of the cell-to-cell passage, septate junctions. However, in all cases, transfer is proportional to the electrochemical gradient.

The model was tested against the results obtained after exposure to TMA+ in short-circuited and open-circuited tissues as well as results from an open-circuited tissue that did not develop a large transepithelial potential. Although driving forces for TMA+ across the membrane barriers were quite different in the different experimental conditions, the transfer coefficients from lumen to columnar cell, from columnar to goblet cell and from both cells across the basal membrane were the same. The only transfer coefficient that changed between short-circuit and open-circuit conditions was that from goblet cell cytoplasm to goblet cavity. This value was high under short-circuit conditions (when K+ transport activity is high), but low under open-circuit conditions (when K+ transport activity is low).

The model suggests a hypothesis in which TMA+ enters the goblet cavity by an indirect route across the cell membrane of columnar cells, and thence passes to the goblet cell cytoplasm through intercellular junctions. Results from experiments with cytochalasin E suggest that the actin-based cytoskeleton is involved in limiting cell–cell coupling. In this model, TMA+ passes from the goblet cell cytoplasm to the goblet cavity via the K+/nH+ antiport believed to mediate active transepithelial K+ transport. However, although actively transported K+ is believed to pass from goblet cavity to lumen, TMA+ cannot.
Sound Production in Crickets
Authors: Stephen R. O. , Hartley J. C.
Published: April 2021

The calls of male Gryllus bimaculatus were digitally recorded under four different conditions: in air; in 80 % He/20 % O2; with the tympana occluded with wax in air and finally in the helium/oxygen mixture. The principal frequency component, usually referred to as the carrier frequency, was analysed in a large sample of chirps recorded in the four conditions. In all four recording conditions, the principal frequency component was found to vary from chirp to chirp. The mean of the distribution of the principal frequency component was different in the four recording conditions. Insects with occluded tympana produced in air a greater dispersion of the principal frequency component than insects with normal functioning ears.

The spectrum of an individual chirp generally contained two frequency components, the principal component, which was related to the plectrumfile strike rate, and a second component, which was related to the free vibration of the wings. The subalar air space volume is shown to act as an acoustic resonator and is important in the filtering and amplification of the sound signal. These observations were confirmed by a model stridulatory system. The model system shows that the resonant frequency of the subalar space is dependent upon the square root of the effective volume of the space.

The results suggest that song generation in crickets is a dynamic process involving an auditory feedback control loop. The singing insects appear to be able to control the plectrum–file strike rate as well as the resonant frequency of the subalar space by changing the relative position of the wings and the abdomen, hence varying the volume.
Non-Linear Dynamics of Neurochemical Modulation of Mosquito Oviduct and Hindgut Contractions
Authors: Messer Adam Catton , Brown Mark R.
Published: April 2021

Microphysiological techniques and computer-based methods of data acquisition and analysis were used to investigate the dynamics of neurochemical action on spontaneous contractions of continuously perfused oviducts and hindguts isolated from female mosquitoes (Aedes aegypti). Proctolin, leucomyosuppressin (LMS), serotonin and octopamine, which are known to modulate insect muscle contractions, and a mosquito neuropeptide, Aedes Head Peptide I (Aea-HP-I), which inhibits host-seeking behavior, were tested in the bioassays. LMS depressed contractile activity in oviducts at concentrations above 10−12 mol l-1, but hindguts did not respond to concentrations below 10−6 mol l-1. Hindgut contractions spontaneously restarted in 10−6 mol l-1 LMS, but only washing out LMS restored activity in oviducts. LMS changed the amplitude of the oviduct contractions, but the dynamics of contraction remained steady. Following recovery of contractions in LMS, hindgut tissues contracted with a more regular pattern.

Serotonin and octopamine had an identical action on oviduct and hindgut tissues. At concentrations greater than 10−8 mol l-1, serotonin eliminated the refractory period between contractions and thus increased the contraction frequency of oviducts. Though the contractions appeared chaotic, state-series analysis proved that serotonin-treated oviducts contracted rhythmically. Above 10−6 mol l-1, serotonin extinguished normal hindgut peristalsis and induced regular fluttering of the anteriormost portion of the hindgut, an effect possibly related to diuresis following the blood meal.

Proctolin failed to stimulate both oviduct and hindgut contractions at concentrations up to 10−6 mol l-1, but at 10−8 mol l-1 induced contractions of cricket hindgut preparations. Aea-HP-I had no effect on either tissue at 10−6 mol l-1 or lower concentrations.

State-series analysis, based on simple manipulations of experimental data, permitted direct observation of the dynamics of oviduct and hindgut contractile activity.
The length dependence of work production in rat papillary muscles in vitro
Authors: Layland Joanne , Young Iain S. , Altringham John D.
Published: April 2021

The influence of length on work production was investigated for rat papillary muscles using the work loop technique. Active and passive length–force relationships were first determined under isometric conditions and the length for maximum force production (Lmax) was derived. Starting from different lengths within the physiological range, a series of work loops was generated using the stimulation phase shift, strain amplitude and cycle frequency previously found to be optimal for power output at 37 °C. The relationship between muscle length and net work was used to determine the length at which work output was maximal (Lopt).

In order to examine the dynamic passive properties of the muscles, unstimulated muscles were subjected to the same regime of sinusoidal oscillation as used for the active loops. From the hysteresis loops, lengthening work (work done to extend the passive muscle), passive shortening work (work returned during shortening) and net energy loss (hysteresis) could be measured.

The decline in net work production at lengths greater than 95 %Lmax could largely be attributed to the rapid and non-linear increase in muscle stiffness and the increase in net energy loss over this range of lengths.

The physiological significance of the length–work relationship is considered and the mechanical properties of active and passive papillary muscles are discussed with reference to sarcomere length and cardiac muscle ultrastructure.
Voltage-dependence of ciliary activity in the ciliate Didinium nasutum
Authors: Pernberg Joachim , Machemer Hans
Published: April 2021

In the gymnostome ciliate Didinium nasutum, swimming behaviour depends upon the cyclic activity of about 3000 cilia. The normal beating mode, resulting in forward swimming of the cell, is characterized by a posteriad effective beat (18 ° left of the longitudinal axis) at a frequency of approximately 15 Hz. Activation of depolarization-sensitive ciliary Ca2+ channels leads to an increase in intracellular Ca2+ concentration and a change in the beating mode. Following rapid reorientation, the effective stroke is anteriad (24 ° right of the longitudinal axis) and the beating frequency is about 26 Hz, resulting in fast backward swimming of the cell. In response to minor depolarizations, and hence small increases in cytoplasmic Ca2+ concentration, the cilia inactivate. Frequency increase and reversal in beat orientation share a single threshold level of membrane potential, since both changes of the beating mode occur simultaneously.
Reliability of Stomach Temperature Changes in Determining Feeding Characteristics of Seabirds
Authors: Wilson Rory P. , Pütz Klemens , Grémillet David , Culik Boris M. , Kierspel Mandy , Regel Jana , Bost Charles A. , Lage Jochim , Cooper John
Published: April 2021

We examined the accuracy of stomach temperature archival units (STAUs), which are typically used to determine feeding activity in marine endotherms, with regard to determination of the time of prey ingestion as well as the number of prey items ingested and their masses. Units were deployed in nine species of free-living seabirds, where feeding conditions were uncontrolled, eight species of captive seabirds, where feeding conditions could be partially controlled, and in laboratory stomach simulations, where variables could be strictly controlled. The quality of data obtained on the timing of feeding, the mass ingested and the number of prey items ingested was subject to two main sources of error (i) those induced by changes in animal activity and (ii) those resulting from the physical form of the STAUs themselves. Animal activity factors considered important included the following: variability in (a) body temperature, (b) stomach blood perfusion, (c) consistency of stomach contents and (d) stomach churning and changes in body orientation. The physical form (size and buoyancy) of the STAU affected the location of the unit within the stomach, and thus the likelihood that ingested prey comes into contact with the sensor. The timing of prey ingestion can generally be determined accurately; however, considerable errors in mass estimates can occur if data acquired using STAUs are not critically assessed. An understanding of these sources of errors will allow researchers to construct STAUs appropriate to the species being studied and to analyze data critically so that errors are reduced.
Matrotrophic Viviparity In The Yellowtail Rockfish Sebastes Flavidus
Authors: Macfarlane R. Bruce , Bowers Michael J.
Published: April 2021

A capacity for matrotrophic viviparity was established in the yellowtail rockfish Sebastes flavidus (Teleostei: Scorpaeniformes). The incorporation of radiolabel into embryos from [14C]phosphatidylcholine present in the maternal serum during gestation provided the first in vivo demonstration of matrotrophy of phospholipid for any viviparous teleost and of any nutrient for a member of the genus Sebastes. Radiolabel content increased as embryos progressed through ontogeny.

Serum proteins of 170 kDa, present in vitellogenic and embryogenic females, but not in earlier stages, in immature females or in males, indicated the presence of vitellogenin in pregnant females and, thus, the potential for matrotrophic supplementation to yolk sequestered before fertilization. The retention of higher molecular mass proteins and highly phosphorylated proteins and the maintenance of total protein content in yolk during early to mid embryogenesis argue for exogenous maternal supply during gestation. As ovarian development proceeded from the oocyte through successive embryonic stages, the distribution of yolk proteins shifted from higher (67–97 kDa) to lower molecular masses (<70 kDa).

The results of these experimental studies corroborate data from field investigations showing that yellowtail rockfish can matrotrophically supplement embryo nutrients obtained before fertilization. Thus, yellowtail rockfish represent a teleost species positioned within the viviparity continuum and not at its extremes.
Function Of Metal-Ion Homeostasis In The Cell Division Cycle, Mitochondrial Protein Processing, Sensitivity To Mycobacterial Infection And Brain Function
Authors: Supek Frantisek , Supekova Lubica , Nelson Hannah , Nelson Nathan
Published: April 2021

A novel Saccharomyces cerevisiae mutant, unable to grow in the presence of 12.5 mmol l−1 EGTA, was isolated. The phenotype of the mutant is caused by a single amino acid change (Gly149 to Arg) in the essential yeast cell division cycle gene CDC1. The mutant could be suppressed by overexpression of the SMF1 gene, which codes for a plasma membrane Mn2+ transporter. We observed that the yeast SMF1 gene shares homology with the mouse Nramp gene. Nramp (Bcg) was cloned as a gene responsible for mouse resistance to infection with mycobacteria and is identical with the Ity and the Lsh genes conferring resistance to infection by Salmonella typhimurium and Leishmania donovani, respectively. Although the cloning of Nramp identified the gene responsible for the resistance of mice to mycobacteria, its function is unknown. We propose that the mammalian protein, like the yeast transporter, is a Mn2+ and/or Zn2+ transporter. Following the phagocytosis of a parasite into the phagosome, the macrophage produces reactive oxygen and/or nitrogen intermediates that are toxic for the internalized bacteria. The survival of the pathogen during the burst of macrophage respiratory activity is thought to be partly mediated by microbial superoxide dismutase (SOD), which contains Mn2+ or Fe2+ in its active centre. Nramp may transport Mn2+ from the extracellular milieu into the cytoplasm of a macrophage and, after the generation of the phagosome, remove Mn2+ from the organelle. Thus, the Mn2+-depletion of the phagosome microenvironment by the Nramp gene product may be a rate-limiting step in the metalloenzyme’s production by the engulfed bacteria. This limitation will restrict the mycobacterial ability to produce active enzymes such as SOD and prevent the propagation of the ingested microorganisms. Conversely, an increased concentration of Mn2+ in the phagosome caused by a defective Nramp transporter (Bcgs) may promote the growth of the mycobacteria and render the organism sensitive to the pathogen.

We use a similar approach to identify, clone and study other metal-ion transporters.
Effect of Temperature on a Voltage-Sensitive Electrical Synapse in Crayfish
Authors: Heitler William J. , Edwards Donald H.
Published: April 2021

The effects of temperature on transmission through the voltage-sensitive giant motor synapse (GMS) were investigated in crayfish both experimentally and in computer simulation. The GMS is part of the fast reflex escape pathway of the crayfish and mediates activation from the lateral giant (LG) command neurone to the motor giant (MoG) flexor motoneurone. The investigation was motivated by an apparent mismatch between the temperature sensitivity of the activation time constant of the GMS, with a Q10 reported to be close to 11, and that of the active membrane properties of LG and MoG, which are thought to have Q10 values close to 3. Our initial hypothesis was that at cold temperatures the very slow activation of the GMS conductance would reduce the effectiveness of transmission compared with higher temperatures. However, the reverse was found to be the case. Effective transmission through the GMS was reliable at low temperatures, but failed at an upper temperature limit that varied between 12°C and 25°C in isolated nerve cord preparations. The upper limit was extended above 30°C in semi-intact preparations where the GMS was less disturbed by dissection. The results of experiments and simulations both indicate that transmission becomes more reliable at low temperatures because the longer-duration presynaptic spikes are able to drive more current through the GMS into the MoG, which is more excitable at low temperatures. Conversely, effective transmission is difficult at high temperatures because the transfer of charge through the GMS is reduced and because the input resistance of MoG is lowered as its current threshold is increased. The effect of the high Q10 of the GMS activation is to help preserve effective transmission through the synapse at high temperatures and so extend the temperature range for effective operation of the escape circuit.s
Limits to sustained energy intake
Authors: Johnson M. S. , Thomson S. C. , Speakman J. R.
Published: April 2021

Laboratory mice (strain MF1) were used to determine whether sustainable rates of energy intake are limited during lactation. Mice raising natural-sized litters (N=71) reached an asymptote in their daily food intake between days 13 and 16 of lactation at 23.1gday−1 and also between litter sizes of 9 and 15 pups (22.8gday−1). A second group of 37 females had their litter sizes manipulated at birth to raise more or fewer offspring than they gave birth to. When the litter size was increased, females did not increase their food intake to match their new litter size. However, when litter size was decreased, females decreased their asymptotic daily food intake during late lactation in relation to the extent of reduction in litter size. Therefore, it appeared that females were limited during late lactation and with large litter sizes. The milk energy exported amounted to 44% of the gross energy intake, and the estimated daily energy expenditure was therefore considerably lower than the sustained energy intake [8.0×RMR(gross), 6.6×RMR(assimilated)], and averaged 3.1×RMR, where RMR is resting metabolic rate. It was not possible to determine whether the apparent limit on sustained energy intake was acting centrally or peripherally because of the asymptotes in both food intake and milk energy output with increasing litter size.
Locomotion in scombrid fishes: visualization of flow around the caudal peduncle and finlets of the chub mackerelScomber japonicus
Authors: Nauen Jennifer C. , Lauder George V.
Published: April 2021

Scombrid fishes are known for high-performance locomotion; however, few data are available on scombrid locomotor hydrodynamics. In this paper, we present flow visualization data on patterns of water movement over the caudal peduncle and finlets (small fins on the dorsal and ventral body margin anterior to the caudal fin). Chub mackerel, Scomber japonicus, ranging in fork length from 20 to 26 cm, swam steadily at 1.2forklengthss−1 in a recirculating flow tank. Small, reflective particles in the flow tank were illuminated by a vertical (xy) or horizontal (xz) laser light sheet. Patterns of flow in the region near the caudal peduncle were measured using digital particle image velocimetry. Patterns of flow along the peduncle and finlets were quantified using manual particle tracking; more than 800 particles were tracked for at least 12ms over a series of tailbeats from each of four fish.

In the vertical plane, flow trajectory and flow speed were independent of the position of the finlets, indicating that the finlets did not redirect flow or affect flow speed. Along, above and below the trailing surface of the peduncle, where the finlets were oriented along the peduncular surface, flow was convergent. Along, above and below the leading surface of the peduncle, where the finlets were absent, the flow trajectory was effectively horizontal. The lack of divergent flow on the leading surface of the peduncle is consistent with cross-peduncular flow formed by the lateral motion of the peduncle interacting with convergent flow resulting from forward movement of the body.

In the horizontal plane, particles illuminated by the xz light sheet situated approximately 3 mm below the ventral body surface were tracked within the laser light sheet for up to 40ms, indicating strong planar flow. As the peduncle decelerates, the most posterior finlet is frequently at an angle of attack of at least 20° to the incident flow, but this orientation does not result in thrust production from lift generation. Finlet 5 does redirect cross-peduncular flow and probably generates small vortices undetectable in this study. These data are the first direct demonstration that the finlets have a hydrodynamic effect on local flow during steady swimming.
Structure–function relationships of A-, F- and V-ATPases
Authors: Grüber Gerhard , Wieczorek Helmut , Harvey William R. , Müller Volker
Published: April 2021

Ion-translocating ATPases, such as the F1Fo-, V1Vo- and archaeal A1Ao enzymes, are essential cellular energy converters which transduce the chemical energy of ATP hydrolysis into transmembrane ionic electrochemical potential differences. Based on subunit composition and primary structures of the subunits, these types of ATPases are related through evolution; however, they differ with respect to function. Recent work has focused on the three-dimensional structural relationships of the major, nucleotide-binding subunits A and B of the A1/V1-ATPases and the corresponding β and α subunits of the F1-ATPase, and the location of the coupling subunits within the stalk that provide the physical linkage between the regions of ATP hydrolysis and ion transduction. This review focuses on the structural homologies and diversities of A1-, F1- and V1-ATPases, in particular on significant differences between the stalk regions of these families of enzymes.
A sport-physiological perspective on bird migration: evidence for flight-induced muscle damage
Authors: Guglielmo Christopher G. , Piersma Theunis , Williams Tony D.
Published: April 2021

Exercise-induced muscle damage is a well-described consequence of strenuous exercise, but its potential importance in the evolution of animal activity patterns is unknown. We used plasma creatine kinase (CK) activity as an indicator of muscle damage to investigate whether the high intensity, long-duration flights of two migratory shorebird species cause muscle damage that must be repaired during stopover. In two years of study, plasma CK activity was significantly higher in migrating western sandpipers (a non-synchronous, short-hop migrant), than in non-migrants. Similarly, in the bar-tailed godwit (a synchronous, long-jump migrant), plasma CK activity was highest immediately after arrival from a 4000–5000km flight from West Africa to The Netherlands, and declined before departure for the arctic breeding areas. Late-arriving godwits had higher plasma CK activity than birds that had been at the stopover site longer. Juvenile western sandpipers making their first southward migration had higher plasma CK activity than adults. These results indicate that muscle damage occurs during migration, and that it is exacerbated in young, relatively untrained birds. However, the magnitude of the increases in plasma CK activity associated with migratory flight were relatively small, suggesting that the level of muscle damage is moderate. Migrants may avoid damage behaviourally, or have efficient biochemical and physiological defences against muscle injury.
IDENTIFICATION, SEQUENCE AND EXPRESSION OF A CRUSTACEAN CARDIOACTIVE PEPTIDE (CCAP) GENE IN THE MOTHMANDUCA SEXTA
Authors: LOI P. K. , EMMAL S. A. , PARK Y. , TUBLITZ N. J.
Published: April 2021

The crustacean cardioactive peptide (CCAP) gene was isolated from the tobacco hawkmoth Manduca sexta. The gene has an open reading frame of 125 amino acid residues containing a single, complete copy of CCAP. Analysis of the gene structure revealed three introns interrupting the coding region. A comparison of the M. sexta CCAP gene with the Drosophila melanogaster genome database reveals significant similarities in sequence and gene structure.

The spatial and temporal expression patterns of the CCAP gene in the M. sexta central nervous system were determined in all major post-embryonic stages using in situ hybridization techniques. The CCAP gene is expressed in a total of 116 neurons in the post-embryonic M. sextacentral nervous system. Nine pairs of cells are observed in the brain, 4.5 pairs in the subesophageal ganglion, three pairs in each thoracic ganglion(T1-T3), three pairs in the first abdominal ganglion (A1), five pairs each in the second to sixth abdominal ganglia (A2-A6) and 7.5 pairs in the terminal ganglion. The CCAP gene is expressed in every ganglion in each post-embryonic stage, except in the thoracic ganglia of first- and second-instar larvae. The number of cells expressing the CCAP gene varies during post-embryonic life,starting at 52 cells in the first instar and reaching a maximum of 116 shortly after pupation. One set of thoracic neurons expressing CCAP mRNA shows unusual variability in expression levels immediately prior to larval ecdysis. Using previously published CCAP immunocytochemical data, it was determined that 91 of 95 CCAP-immunopositive neurons in the M. sexta central nervous system also express the M. sexta CCAP gene, indicating that there is likely to be only a single CCAP gene in M. sexta.
Characteristic features and ligand specificity of the two olfactory receptor classes fromXenopus laevis
Authors: Mezler Mario , Fleischer Jörg , Breer Heinz
Published: April 2021

Amphibia have two classes of olfactory receptors (ORs), class I (fish-like receptors) and class II (mammalian-like receptors). These two receptor classes correspond to the two classes identified in other vertebrates, and amphibians thus provide a unique opportunity to compare olfactory receptors of both classes in one animal species, without the constraints of evolutionary distance between different vertebrate orders, such as fish and mammals. We therefore identified the complete open reading frames of class I and class II ORs in Xenopus laevis. In addition to allowing a representative comparison of the deduced amino acid sequences between both receptor classes, we were also able to perform differential functional analysis. These studies revealed distinct class-specific motifs, particularly in the extracellular loops 2 and 3, which might be of importance for the interaction with odorants, as well as in the intracellular loops 2 and 3, which might be responsible for interactions with specific G-proteins. The results of functional expression studies in Xenopus oocytes, comparing distinct receptor types, support the idea that class I receptors are activated by water-soluble odorants, whereas class II receptors are activated by volatile compounds.
Direct measurement of oxygen partial pressure in a flying bumblebee
Authors: Komai Yutaka
Published: April 2021

The gas transport system of a bumblebee was investigated by measuring the oxygen partial pressure PO2 in the wing muscle. In the resting bee, PO2 showed a regular pattern of fluctuation with a typical period of 70–120s. Fluctuations in muscular PO2 were associated with intermittent abdominal pumping. Ventilation by abdominal movements may not be necessary during rest because PO2 is high (8.5–9.2kPa) in the anaesthetised bee. Thermal effects on muscular PO2 were examined by cooling the bee, causing the amplitude of PO2 fluctuations to increase. In most flight experiments, the bee started to fly after elevating muscle PO2 by abdominal pumping; muscle PO2 then decreased at the onset of flight. However, when a flight began without pre-flight ventilation, PO2 increased monotonically. During flight, muscle PO2 reached a mean level (6.36±1.83kPa) that was much higher than the lowest value recorded during discontinuous ventilation during rest. The bumblebee effectively uses abdominal movements to assist in convective gas transport not only during flight but also at rest.
Effect of food shortage on the physiology and competitive abilities of sand martin (Riparia riparia) nestlings
Authors: Brzęk Pawel , Konarzewski Marek
Published: April 2021

We examined developmental and behavioural plasticity of sand martin (Riparia riparia) nestlings hand-reared under laboratory conditions. We created six broods of six 4-day-old nestlings and randomly assigned them to one of the two following feeding regimens, each lasting for 3 days: (1) all nestmates fed a similar, limited amount of food (FR nestlings). This simulated synchronous hatching under conditions of food restriction. (2) Half the brood were food-restricted (FR/AL nestlings), and half were fed ad libitum (AL nestlings), as in asynchronously hatched broods with differential food allocation. Under both regimens, food restriction resulted in a reduction in body mass, intestinal mass, pectoral muscle mass, fat reserves, body temperature and resting metabolic rate (RMR). However, it simultaneously triggered a significant increase in intestinal uptake rates of l-proline and locomotor activity, quantified as frequency of crawling into the artificial nest tunnel by individual nestlings. Locomotor activity and intestinal uptake rates of l-proline by FR nestlings were higher than those of FR/AL young, while body temperature and RMR of FR nestlings were lower.

We conclude that food-restricted nestlings responded actively to food shortages by upregulating their gut function, reducing the energy costs of maintenance and increasing locomotor activity. These behavioural and physiological responses were strongest in broods of similar-sized FR nestlings, which can be interpreted as an escalation of sibling competition. Thus, developmental and behavioural plasticity may be an important factor in the evolution of sibling rivalry.
Standard metabolic rate at the surface and during trained submersions in adult California sea lions (Zalophus californianus)
Authors: Hurley Jenifer A. , Costa Daniel P.
Published: April 2021

The metabolic rate (MR) of four adult California sea lions (Zalophus californianus), two males and two females, was quantified during trained submersion and stationing behavior in laboratory tanks. MR was measured, at rest and for single submersions of increasing duration (1–7 min), by measuring oxygen consumption using open-circuit, indirect calorimetry. Standard MR was measured under conditions defined for basal MR and was found to be 1.9 to 3 times that predicted for terrestrial animals of similar size. Submersion MRs were calculated from the post-submersion oxygen debt and declined to as little as 47 % of standard MR on the longest submersions. This hypometabolic response was proportional to the duration of submersion and was greatest for the maximum duration submersions. Short submersions produced MRs equivalent to measured standard MR. These data suggest that although California sea lions maintain an elevated metabolism under standard conditions, they are capable of reducing their metabolism in response to the needs of diving. Such metabolic flexibility enables sea lions to moderate their oxygen use during diving and to extend their aerobic diving capability.
An unusual case of Adrenocortical Adenocarcinoma with Biochemical Masquerade of Pheochromocytoma
Authors: Ali Muzaffar , Mirza Lubna
Published: April 2021

Adrenocortical carcinoma (ACC) is a rare malignancy that arises from the adrenal cortex and often presents as adrenal incidentaloma on abdominal scans with rise in the use of imaging modalities. ACC often presents as Cushing’s syndrome or virilization. On the other hand, pheochromocytoma is an adrenal medullary tumor. It is rare for ACC to present as pheochromocytoma even though both may coexist. Moreover, ACC tumors have radiological and histological features suggestive of aggressive nature of the disease.

We present a case of a 65-year-old lady who initially presented with a 3cm left adrenal incidentaloma. All of her adrenal hormones were in normal range. She was lost to follow up for several years and returned with a much enlarged lesion. Biochemical work up showed mildly increased catecholamines and metanephrines suggestive of pheochromocytoma. She didn’t have any signs or symptoms of pheochromocytoma. She was treated with alpha blockers before surgery as a prophylactic measure. Surgical pathology was consistent with the diagnosis of primary adrenal adenocarcinoma. We recommend that adrenal incidentalomas should be followed annually for up to five years as per American association of Endocrinology and the Endocrine Society guidelines to prevent morbidity and mortality in patients.

doi: https://doi.org/10.12669/pjms.37.4.3916

How to cite this:Ali M, Mirza L. An unusual case of Adrenocortical Adenocarcinoma with Biochemical Masquerade of Pheochromocytoma. Pak J Med Sci. 2021;37(4):1241-1243. doi: https://doi.org/10.12669/pjms.37.4.3916

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Antimicrobial effects of fruit sauces on some pathogenic bacteria in vitro and on chicken breast meat
Authors: VAR I , UZUNLU S , DEĞIRMENCI I
Published: April 2021

The use of natural food additives is currently a rising trend. In the present study, the aim was to determine the antimicrobial effects of plum, pomegranate, Seville orange and sumac sauces on E. coli O157:H7,E. coli type I,Listeriamonocytogenes, Listeria ivanovii, Salmonella Typhimurium and Staphylococcus aureus. Different concentrations (1%, 10%, 100%, v/v) of the sauces were tested on the studied bacteria in vitro using the agar diffusion and minimal inhibition concentration (MIC) methods. The results showed that the sumac sauce had the highest antimicrobial activity. The Seville orange, plum and pomegranate sauces also exerted antimicrobial activity in descending order. The antimicrobial activity of the fruit sauces was more effective at a concentration of 100% than at 10% and 1%, v/v. The most inhibitory effect was recorded for sumac sauce at a concentration of 100% (v/v) on L.monocytogenesand E. coli O157:H7. The findings of the MIC method aligned with the agar diffusion method. In addition, the in situ(food method) antimicrobial effect of the sauces on the indigenous microflora of chicken breast samples sold in stores was determined. Chicken samples hosting aerobic mesophilic bacteria, coliforms and E. coli were treated for two hours at 4 °C with plum, pomegranate, Seville orange and sumac sauces and were then monitored. The findings revealed that the Seville orange and sumac sauces were the most effective in reducing the indigenous microbial growth on the chicken samples. The plum sauce showed higher antimicrobial activity than pomegranate sauce. The phenolic content and acidity of the samples significantly (P< 0.05) affected the antimicrobial activity both in vitro (agar diffusion and MIC) and in situ (chilled chicken breast). In conclusion, the sumac and Seville orange sauces were found to be the most promising natural antibacterial agents, and their use could be recommended, for example, in catering services to reduce the risk of foodborne illness.
Sarcoptes scabiei dermatitis in adult sheep: an immunohistochemical study of 34 chronic cases with extensive lesions
Authors: DOUKAS D , LIAKOU Z , TONTIS D
Published: April 2021

Ovine sarcoptic mange is a contagious ectoparasitic skin disease, seen in many countries with sheep production. Although several studies concerning dermatopathology have been published, the local cutaneous immune response to Sarcoptes scabiei has not been studied by immunohistochemistry. The present study aims to evaluate immunohistochemically the adaptive cellular immune response in chronic natural cases with extensive gross lesions. Facial and foot skin biopsies of 32 ewes and 2 rams were obtained, and moreover from the scrotal scabietic lesions of the 2 rams. Each biopsy was bisected and processed for paraffin and cryostat sections. Mites were not observed in the vast majority of skin histology sections. Epidermal hyperplasia and chronic inflammation were the main histopathologic features. The dermal inflammatory infiltrate was mixed, dominated by eosinophils and lymphocytes equally. Tissue sections immunostained with a panel of monoclonal antibodies showed among lymphocytes an almost exclusively T-cell population (CD3+), while CD79a + cells were sparse. T-helper cells (CD4+) were predominant versus T-cytotoxic cells (CD8+) in 4:1 to 5:1 ratios. The mixed inflammatory infiltrate combined with the immunohistochemical findings suggest both a type-I and type-IV hypersensitivity reactions during the chronic course of the disease. Moreover, all these chronic cases in adult sheep are recorded into the hypersensitivity form of sarcoptic mange (“classical or ordinary” scabies) and no cases of the hyperkeratotic form of the disease (“Norwegian or crusted” scabies) were found.
Hematological and Biochemical Parameters of Pregnant and Lactating Goats in Rangeland of Cholistan Desert, Bahawalpur, Pakistan
Authors: LASHARI MH , AHMAD I , MASOOD S , FAROOQ U , ANAM M , AKHTAR MS , FAROOQ AA , LEGHARI S , NAEEM M , NAWAZ M
Published: April 2021

Jattal goats (n=90) of approximately 2-6 years of age being reared in Cholistan desert of Pakistan were studied during January to December, 2015 to examine the alterations in hematochemical parameters of Jattal goats at different reproductive phases while feeding on natural vegetations of desert areas of Cholistan. These were divided into three equal groups (non-pregnant, pregnant and lactating). Blood samples were collected by jugular vein puncture from goats of these three groups. Hematological parameters, white blood cells (WBC), lymphocytes (LYM), monocytes (MON), granulocytes (GRA), red blood cells ( RBC), hemoglobin (Hb), hematocrit ( HCT), mean corpuscular volume (MCV), mean cell hemoglobin (MCH), mean cell hemoglobin concentration ( MCHC) and red cell distribution width RDW were recorded. The results obtained revealed that all these parameters were generally lower in non-pregnant goats. The study revealed that significant higher values of hemoglobin (Hb), mean cell hemoglobin (MCH) and mean corpuscular volume (MCV) were observed in the lactating goats (P<0.05). Pregnant goats showed a significantly (P<0.05) higher values of leucocytes (WBC) than lactating and non-pregnant goats. Plasma sodium (Na) and potassium (K) concentration were markedly lower in lactating goats. Plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were significantly lower in pregnant goats. The Plasma concentration of cholesterol and triglycerides were higher in pregnant goats. In conclusion in present study changes in some hematochemical parameters have been determined in pregnant, non-pregnant and lactating goats of Jattal breed.
A bioactive compound isolated from Duku (Lansium domesticum Corr) fruit peels exhibits cytotoxicity against T47D cell line
Authors: Fadhilah Khusnul , Wahyuono Subagus , Astuti Puji
Published: April 2021

Background: Breast cancer is a major health problem for women globally. Many attempts have been promoted to cure cancer by finding new anticancer medicines from natural resources. Despite the richness of biodiversity discovered, there are some natural resources that remain unexplored. Fruit peels of Duku (Lansium domesticum Corr.) are rich with compounds that may have the potential to be developed as anticancer drugs. This study aimed to isolate cytotoxic compounds from the fruit peels of L. domesticum and assess their cytotoxic nature against T47D cells.

Methods: Powdered peels were macerated with ethyl acetate and the filtrate was evaporated to give EtOAc extract A. Dried extract A was triturated with n-hexane to give n-hexane soluble fraction B and insoluble fraction C. The cytotoxic nature of these three  samples were assessed using MTT assay using T47D cells and doxorubicin as a control.

Results: Fraction C that showed the smallest IC50 (25.56 ± 0.64μg/mL) value compared to  extract A and fraction B. Fraction C was further fractionated by vacuum liquid chromatography to give 6 subfractions. Subfraction 2 showed a single compound based on thin layer chromatography, and this compound was identified as Lamesticumin A on the basis of its spectroscopic data. Lamesticumin A demonstrated cytotoxic activity against T47D cell lines with an IC50 value of 15.68 ± 0.30µg/mL.

Conclusions: Further research is needed to investigate the potential of the natural compound Lamesticumin A derived from L. domesticum fruit peel as an anticancer therapy.
Mechanizmy rynkowe i interwencja państwa w polityce regionalnej Chińskiej Republiki Ludowej
Authors: Świstak Marek
Published: April 2021

Market Mechanisms and State Intervention in Diversifying the Regional Development of the People’s Republic of China

The article focuses on the importance of market mechanisms and state intervention in the field of regional development policy, in particular on the dominant process of development differentiation. The aim of the article is to verify to what extent market mechanisms are the driving force in China’s regional development policy, and to what extent state intervention is the driving force. It is also important because of the fact that regional policy is an amalgam of the public intervention and presence of market forces, regardless of the country’s political regime. The article identifies the elements that determine the differentiation of regional development due to the operation of market mechanisms and state intervention in China’s regional policy.
Die Entwicklung des Konzepts von Hans-Dietrich Genscher in der bundesdeutschen Entspannungspolitik in den Jahren 1974-1989. Herkunft – Instrumente – Auswirkungen
Authors: Węc Janusz Józef
Published: April 2021

The Evolution of the Concept of Hans-Dietrich Genscher in the German Détente Policy in the Years 1974-1989. Genesis – Instruments – Impact

The main aim of this article is to present the genesis, instruments and real influence of the concept of the “realistic” détente policy of the German Minister of Foreign Affairs Hans-Dietrich Genscher on the foreign policy of the German federal government in the years 1974-1989. The author formulates a thesis that Genscher’s concept had very significant influence on the program activities of the FDP as well as on the practical foreign policy of the SPD/FDP governments (1974-1982) and CDU/CSU/FDP governments (1982-1989), whereby the year 1985 was an important turning point in this evolution.
Fenomen studiów nad Chinami w Instytucie Bliskiego i Dalekiego Wschodu Uniwersytetu Jagiellońskiego
Authors: Gacek Łukasz , Trojnar Ewa
Published: April 2021

The Phenomenon of China Studies at the Institute of the Middle and Far East of the Jagiellonian University

Modern China became the phenomenon eagerly investigated by wide circles of observers. This trend is associated with a growing number of academic fields with the Asiatic profile on the level of university education. Such characteristics is completely reflected in studies conducted at the Institute of the Middle and Far East of the Jagiellonian University. The purpose of this research is to comprehend a phenomenon of the current interest in Asia developed in Poland, with an example of China, among students of fields at the Institute with the Chinese profile. In recent years, the Institute of the Middle and Far East of the Jagiellonian University became the largest academic institution in Poland conducting this type of studies in nonphilological fields. Research proved that studies on China match the need of educating persons who both know Chinese and have specific knowledge about this country. Uniqueness of the field of study and created professional chances appeared to be equally important.
Ekonomia polityczna i problemy badań relacji między ekonomią a polityką
Authors: Dardziński Piotr
Published: April 2021

Abstract
‘Lighting a spark’
Authors: Henty Neil
Published: April 2021

Neil Henty speaks to Beverley Kellett, head of South Acton Children's Centre, about the importance of investing in staff training – what that looks like, how to go about it, and where it can lead.