Changes In Internal Morphology Research Articles

Effects of four types of packaging on the structural characteristics, quality attributes, and antioxidant activity of foxtail millet during storage

ABSTRACT The aim of this study is to select suitable packaging for extending the shelf-life of foxtail millet grains (FMG). FMG were packaged in four types of packaging and subsequently stored at room temperature (25°C ± 1°C) for 6 months. The effects of four types of packaging on the corresponding structural characteristics, quality attributes, and antioxidant activity of FMG were investigated. The results showed that aging led to less-prominent internal morphological changes with the vacuum- and N2-packaged samples. Moreover, vacuum and N2 packaging retarded the increase of fat acidity and the decrease of yellowness (b*) during storage. Aging in cotton and polyamide–polyethylene (PA/PE) packaging resulted in less soluble solids leakage during cooking, leading to more reduction in stickiness. No changes in hardness of cooked FMG were found only for vacuum packaging. In addition, total phenolic content and antioxidant capacities were well preserved under vacuum or N2 conditions. Overall, vacuum packaging was more effective in retarding the quality deterioration of FMG when compared to the other storage conditions.

Research on EIS characterization and internal morphological changes of LIBs during degradation process

Electric vehicles (EVs) are increasingly being used today, but the safety of their battery system remains an issue. Therefore, a clear understanding of the degradation mechanism of EV batteries has become a pressing issue. In this study, the EIS characterization and internal morphological changes are investigated during degradation process of 18,650 LIBs. The research results show that the EIS value of LIBs changes to varying degrees with battery degradation, but this change is not only due to the ageing of LIB materials, but also related to the LIB’s state of charge. In lithium-ion battery EIS, the ohmic impedance is mainly influenced by the SOH, while the transfer impedance and extended impedance are influenced by the SOC of the battery. In addition, as the aging process progresses, the particles of the anode and cathode materials of the LIB gradually become smaller and more fragmented, the decomposition on the surface of the negative electrode becomes more significant, which is mainly due to the fact that the decomposition of the graphite negative electrode is more pronounced, which evidenced by scanning electron microscopy (SEM) images. These new finds will help further improve the design and management of LIBs.

Azadirachtin-based insecticide impairs testis morphology and spermatogenesis of the southern armyworm Spodoptera eridania (Lepidoptera: Noctuidae).

In the search for alternative tools for integrated pest management, azadirachtin, a botanical insecticide, has been used with the most promising activity against Spodoptera spp., but the mechanism of cytotoxicity on reproductive organs remains unclear. Spodoptera eridania (Stoll, 1782) is a polyphagous pest with great economic importance that has become an important target to elucidate the action of azadirachtin on the reproductive organs of insect pests, helping to understand the deleterious effects caused by its exposure. This study evaluated the effects of chronic exposure to azadirachtin on the morphology and ultrastructure of S. eridania larval testes as well as larval development. Azadirachtin exposure (6 or 18 mg a.i.L-1 ) caused a progressive increase in cumulative mortality and reduced gain in body mass after 5 days. Testicular structure indicated a reduction in their size with internal morphological changes such as spermatogonia, spermatogonial, spermatocytes and spermatid cysts in degeneration. The occurrence of cell death in germ and somatic cells was evidenced by the TUNEL technique. Electron microscopy revealed changes in cystic cells, such as cytoplasmic membrane rupture and cytoplasmic vacuolization. Chromatin compaction, changes in the rough endoplasmic reticulum and Golgi complex cisternae were observed in germ cells. Apoptotic bodies occurred between germ cell cysts. Azadirachtin damaged the testes of S. eridania larvae, and these changes compromised spermatogenesis and consequently the development of the reproductive potential of this specimen, making azadirachtin a promising botanical insecticide for application in integrated pest management programs. © 2022 Society of Chemical Industry.

Multimethod combination for age estimation of Sarcophaga peregrina (Diptera: Sarcophagidae) with implications for estimation of the postmortem interval.

Sarcophaga peregrina (Robineau-Desvoidy, 1830) (Diptera: Sarcophagidae) is a forensically important flesh fly with potential value for estimating the minimum postmortem interval (PMImin). Here, the developmental patterns of S. peregrina were investigated at 5 constant temperatures (15-35°C). Morphological changes at different developmental stages of the pupa were observed at 4 constant temperatures (15-30°C) by removing the puparium and staining the pupa with hematoxylin and eosin. Furthermore, differentially expressed genes (DEGs) were analyzed at 25°C in the intrapuparial period to estimate the age of S. peregrina during the intrapuparial stage. S. peregrina completed development from larviposition to adult eclosion at 15°C, 20°C, 25°C, and 30°C; the developmental durations were 1090.3 ± 30.6h, 566.6 ± 21.9h, 404.6 ± 13.01h, and 280.3 ± 4.5h, respectively, while the development could not be completed at 35°C. The intrapuparial period of S. peregrina was divided into 12 sub-stages on the basis of the overall external morphological changes; 6 sub-stages on the basis of individual morphological structures such as the compound eyes, antennae, thorax, legs, wings, and abdomen; and 10 sub-stages on the basis of internal morphological changes detected using histological analysis. The period of each sub-stage or structure that appeared was determined. Moreover, we found that 6 genes (NDUFS2, CPAMD8, NDUFV2, Hsp27, Hsp23, and TPP) with differential expression can be used for the precise age estimation of S. peregrina during the intrapuparial period. This study provided basic developmental data for the use of S. peregrina in PMImin estimation, and we successfully estimated PMImin in a real forensic case by using a multimethod combination.

Development of sexual structures influences metabolomic and transcriptomic profiles in Aspergillus flavus

Sclerotium (female) fertility, the ability of a strain to produce ascocarps, influences internal morphological changes during sexual reproduction in Aspergillus flavus. Although sclerotial morphogenesis has been linked to secondary metabolite (SM) biosynthesis, metabolic and transcriptomic changes within A. flavus sclerotia during sexual development are not known. Successful mating between compatible strains may result in relatively high or low numbers of ascocarps being produced. Sclerotia from a high fertility cross (Hi-Fert-Mated), a low fertility cross (Lo-Fert-Mated), unmated strains (Hi-Fert-Unmated and Lo-Fert-Unmated) were harvested immediately after crosses were made and every two weeks until 8 weeks of incubation, then subjected to targeted metabolomics (n = 106) and transcriptomics analyses (n = 80). Aflatoxin B1 production varied between Hi-Fert-Mated and Hi-Fert-Unmated sclerotia, while it remained low or was undetected in Lo-Fert-Mated and Lo-Fert-Unmated sclerotia. Profiling of 14 SMs showed elevated production of an aflavazole analog, an aflavinine isomer, and hydroxyaflavinine in Hi-Fert-Mated sclerotia at 4 to 8 weeks. Similarly, genes ayg1, hxtA, MAT1, asd-3, preA and preB, and genes in uncharacterized SM gene clusters 30 and 44 showed increased expression in Hi-Fert-Mated sclerotia at these time points. These results broaden our knowledge of the biochemical and transcriptional processes during sexual development in A. flavus.

Chemical Garden Membranes in Temperature-Controlled Microfluidic Devices.

Thin-walled tubes that classically form when metal salts react with sodium silicate solution are known as chemical gardens. They share similarities with the porous, catalytic materials in hydrothermal vent chimneys, and both structures are exposed to steep pH gradients that, combined with thermal factors, might have provided the free energy for prebiotic chemistry on early Earth. We report temperature effects on the shape, composition, and opacity of chemical gardens. Tubes grown at high temperature are more opaque, indicating changes to the membrane structure or thickness. To study this dependence, we developed a temperature-controlled microfluidic device, which allows the formation of analogous membranes at the interface of two coflowing reactant solutions. For the case of Ni(OH)2, membranes thicken according to a diffusion-controlled mechanism. In the studied range of 10-40 °C, the effective diffusion coefficient is independent of temperature. This suggests that counteracting processes are at play (including an increased solubility) and that the opacity of chemical garden tubes arises from changes in internal morphology. The latter could be linked to experimentally observed dendritic structures within the membranes.

Internal morphological changes during metamorphosis in the sheep nasal bot fly, Oestrus ovis.

During the larval stage, oestrid flies (Diptera: Oestridae) are obligate parasites, whereas during the adult stage they are free-living and do not feed. Like other cyclorrhaphous flies, oestrids undergo metamorphosis inside an opaque puparium, formed by the contracted and hardened cuticle of the third-instar larva. The present study documents the internal morphological changes taking place during metamorphosis of the sheep nasal bot fly, Oestrus ovis L., using non-invasive, micro-CT-based virtual histology and provides quantitative data of volumetric changes in specific organs. Virtual histological sections allowed visualisation of the progression and completion of the apolyses, which delimit the different intra-puparial stages, and the connection to the tracheal system of a large gas bubble, which plays an essential role during early metamorphosis. Overall, our results show that the sequence of morphological and volumetric changes in tissues and organs is similar to those found in other cyclorrhaphous flies, but they also reveal developmental differences that result in an adult vestigial digestive tract. Future studies could develop non-invasive, reliable methods for aging the intra-puparial forms of different oestrid species of veterinary importance, based on both qualitative and quantitative markers, thus improving our knowledge of their development and the efficiency of control strategies.

Morphological changes and habitat shifts with growth of endangered floodplain fish: Possible adaptations to fluctuating environments

AbstractAdaptations that maximise food intake are dependent on food and/or habitat types. However, there have been few studies on the ability of floodplain primary freshwater fish to rapidly change their morphology, especially the internal one, to maximise utilisation efficiency of food resources in response to environmental fluctuations during their life history. We investigated morphological changes of an Acheilognathinae species (Acheilognathus longipinnis) that inhabits creeks in Japan to determine whether body shape variation correlated with environmental characteristics, including water depth, current velocity, vegetation cover and food availability. When shifting from floodwater‐level to low‐water‐level season, the current velocity of the study area increased as the water level decreased, causing a significant increase in periphyton and a significant decline in zooplankton and phytoplankton. Concurrently, during the short period when A. longipinnis grow from the juvenile to the premature stage, changes in internal morphology, that is intestinal elongation, and changes in external morphology such as an increase of body depth were observed. In contrast, intestinal length significantly decreased in the adult stage. Our findings suggest that morphological changes between floodwater‐level and low‐water‐level seasons associated with juvenile to premature development are an adaptation to changes in food availability due to environmental fluctuations. Additionally, the shortening of the intestine from the premature to the adult stage may be an adaptive strategy for reproduction.

Temperature dependence of structural alteration by ultraviolet irradiation in acrylic-urethane coatings studied by positron annihilation spectroscopy and solvent swelling behavior

The structural alteration of acrylic-urethane coatings, induced by photo-aging, and its temperature dependence, was investigated using positron annihilation lifetime spectroscopy and solvent swelling experiments. The results revealed a slight structural alteration due to photo-aging at 20 °C. On the other hand, a significant structural alteration occurred due to photo-aging at 60 °C, which resulted in a decrease in the pore size and total pore volume. To study the mechanism of such morphological changes, infrared spectra were measured before and after aging the samples. The results revealed the breakage of the urethane crosslink points and the generation of various photo-products including peroxide species that can form hydrogen bonds. This indicates the foundation of new physical and chemical crosslinks (different from the initial urethane linkage). Based on the chemical modifications, probable mechanisms of the internal morphological changes are proposed. Moreover, the changes are mainly due to an enhancement in the chain-mobility, due to the destruction of the polymer network and an increase in the inter-chain interactions. The results of this study reveal that significant internal structural alterations can occur after sufficient damage to the initial network structure. The proposed explanation is reasonable in relation to the temperature dependence of photo-induced structural alterations, and with respect to the molecular mobility and reaction ratio of photo-oxidation.

ASSESSMENT OF OSSEOUS DENSITY CHANGES IN PATIENTS WITH MEDICATION-RELATED OSTEONECROSIS OF THE JAWS USING CONE-BEAM CT: A CASE CONTROL STUDY

Objective: In this study, the aim was to analyze density differences in prearranged region of patients with medication-related osteonecrosis of the jaws (MRONJ) and to evaluate potential effected sides in jaws by using cone beam computed tomography (CBCT)Material and Methods: The records of 29 patients diagnosed with MRONJ and under bisphosphonates therapy and examined by CBCT were retrospectively evaluated with age- and gender-matched controls. The gray values (voxel value (VV)) were detected in the maxillary tuberosity (MTs), anterior supporting bone of nasopalatine canal (NPCs), mental foramen regions (MFs), center of symphysis and the bone surrounding the MRONJ area.Results: According to the results, the mostly affected area was the bone under the mental foramen. There were significant differences between MRONJ and controls for right and left MFs (p=0.03, p=0.006 respectively). The mean gray value of right MTs were: 165.04 for controls and 212.4 for patients (p=0.13); left MTs were 208.6 for controls and 268.0 for patients (p=0.32); NPCs were 575.1 for controls and 572.6 for patients (p=0.96); and MSs were 679.2 for controls and 828.2 for patients (p=0.1). The gray value in the inferior peripheral bone of exposed region was the highest.Conclusion: The present study shows that bisphosphonates cause internal morphological changes in jaws. Morphological changes are more frequent in certain parts of the jawbone such as the mental foramen. Gray values obtained by CBCT for quantitative measurements of density differences, can help achieve useful data for prediction of hazardous conditions where MRONJ can occur and how it will progress.

Planar Lithium Battery Cell Development to Advance in-Operando Nano-CT Imaging of Graphite Electrodes

In-operando nano-scale resolution X-ray computed tomography (nano-CT) imaging provides an excellent new possibility to investigate a wide variety of phenomena in the electrodes of Li-ion batteries. The 3D X-ray imaging provides direct observation of internal morphological changes in electrodes with up to 50 nm resolution regarding standard materials and electrolyte, which is difficult or impossible to achieve by electron microscopy. Such fine resolution enables the possibility to observe detailed structural changes like the deposition of electrolyte decomposition products within the electrode, transition from Li intercalation to electroplating on graphite, and lithium dendrite formation and growth. One task for applying in-situ nano-CT imaging on Li-ion battery imaging is to develop special lithium battery cells compatible with both the nano-CT instrument’s sample size constraint and X-ray attenuation length limits of higher atomic number materials. Herein, we have developed a planar cell design that allows us to use commercial electrode, separator, and electrolyte. Successful charging and discharging has been achieved with this planar cell design using commercial graphite, LiMn2O4, and lithium foil electrodes. In-operando nano-CT imaging is performed on planar cell lithium battery with focus on graphite anodes. The experimental methodology developed in this study has applicability to test wide ranges of electrolyte, separators and other electrode materials in Li-ion batteries.

Looking into the puparium: Micro-CT visualization of the internal morphological changes during metamorphosis of the blow fly, Calliphora vicina, with the first quantitative analysis of organ development in cyclorrhaphous dipterans.

Metamorphosis of cyclorrhaphous flies takes place inside a barrel‐like puparium, formed by the shrinking, hardening and darkening of the third‐instar larval cuticle. The opacity of this structure hampers the visualization of the morphological changes occurring inside and therefore a full understanding of the metamorphosis process. Here, we use micro‐computed tomography (micro‐CT) to describe the internal morphological changes that occur during metamorphosis of the blow fly, Calliphora vicina Robineau‐Desvoidy 1830 (Diptera: Calliphoridae) at a greater temporal resolution than anything hitherto published. The morphological changes were documented at 10% intervals of the total intra‐puparial period, and down to 2.5% intervals during the first 20% interval, when the most dramatic morphological changes occur. Moreover, the development of an internal gas bubble, which plays an essential role during early metamorphosis, was further investigated with X‐ray images and micro‐CT virtual sections. The origin of this gas bubble has been largely unknown, but micro‐CT virtual sections show that it is connected to one of the main tracheal trunks. Micro‐CT virtual sections also provided enough resolution for determining the completion of the larval‐pupal and pupal‐adult apolyses, thus enabling an accurate timing of the different intra‐puparial life stages. The prepupal, pupal, and pharate adult stages last for 7.5%, 22.5%, and 70% of the total intra‐puparial development, respectively. Furthermore, we provide for the first time quantitative data on the development of two organ systems of the blow fly: the alimentary canal and the indirect flight muscles. There is a significant and negative correlation between the volume of the indirect flight muscles and the pre‐helicoidal region of the midgut during metamorphosis. The latter occupies a large portion of the thorax during the pupal stage but narrows progressively as the indirect flight muscles increase in volume during the development of the pharate adult.

Are there any differences in mandibular morphology of patients with bisphosphonate-related osteonecrosis of jaws?: a case-control study.

The aim of this study was to compare the morphological differences in the mandible between patients with bisphosphonate-related osteonecrosis of the jaw (BRONJ) and healthy individuals and to detect the correlation between these parameters on panoramic radiography and CBCT. The CBCT and panoramic images of patients with BRONJ (n = 32) and control groups (n = 32) were included in the study. All the comparisons were analyzed between the osteonecrosed and healthy sides of patients with BRONJ and control group. The panoramic radiographs were used to measure the values of the condyle angle, gonial angle, antegonial angle, antegonial depth, condylar height and ramal height. The mandibular cortical index (MCI) and bone quality index (BQI) were also examined on cross-sectional scans of CBCT images. There were significant differences in the MCI (p = 0.014) and BQI (p = 0.021) between the left and right side of the BRONJ group and also between the osteonecrosed side of the BRONJ and control group (p < 0.0001). No significant difference was found in other comparisons. The outcomes of the present study indicate that bisphosphonates influenced some internal morphological changes in the mandible. These changes may be a reason of BRONJ. But, these changes are not reflective of the measured values obtained using panoramic radiographs on the external morphology of the mandible.

Endocrine control of embryonic diapause in the Australian sharpnose shark Rhizoprionodon taylori.

The reproductive cycle of the Australian sharpnose shark, Rhizoprionodon taylori, includes a temporary suspension of development at the commencement of embryogenesis termed embryonic diapause. This study investigated levels of 17β-estradiol (E2), testosterone (T) and progesterone (P4) in plasma samples of mature wild female R. taylori captured throughout the reproductive cycle and correlated them with internal morphological changes. Levels of T were elevated through most of the embryonic diapause period, suggesting a role of this hormone in the maintenance of this condition. Increasing plasma T concentrations from late diapause to early active development were associated with a possible role of androgens in the termination of embryonic diapause. As in other elasmobranchs, a concomitant increase of E2 with ovarian follicle size indicated a direct role of this hormone in regulating vitellogenesis, while a peak in P4 suggested this hormone is associated with preovulation and ovulation. Additionally, significant correlations between photoperiod or water temperature and maximum follicular diameter and hepatosomatic index suggest that these abiotic factors may also play a role triggering and regulating the synchrony and timing of reproductive events.

Reductions in flesh discolouration and internal morphological changes in Nanhui peaches (Prunus persica (L.) Batsch, cv. Nanhui) by electrolysed water and 1-methylcyclopropene treatment during refrigerated storage

The effects of electrolysed water (EW) and EW in combination with 1-methylcyclopropene (EW/MCP) on flesh discolouration of Nanhui peaches (Prunus persica (L.) Batsch, cv. Nanhui) were examined during storage at 2°C. Changes in flesh colour, ethylene production, membrane permeability, malondialdehyde (MDA), total phenolic contents and the activities of polyphenol oxidase (PPO) and peroxidase (POD) were assayed periodically after harvest and during 44days of storage. The internal morphological characteristics of Nanhui peaches were monitored using magnetic resonance imaging (MRI) at the beginning and end of storage. These data revealed that the EW/MCP treatment is more effective than the EW treatment for decreasing ethylene production and maintaining fruit cell membrane integrity, delaying increases in MDA and total phenolic contents, and lessening changes in PPO and POD activities and the internal morphology of peaches. Each of these effects contributes to suppressing flesh discolouration and maintaining the quality of Nanhui peaches during storage.

Modified Field stain - rapid viability test for Trichomonas vaginalis

We previously reported that Modified Field Stain (MF) can be used as a rapid stain for diagnosis. In the present study we extend the observation to include the stain as an alternative method to assess viability of the cells. Six isolates of Trichomonas vaginalis were used to assess the utility of the Modified Field stain as a rapid viability test for T. vaginalis and to compare with 0·4% Trypan Blue dye exclusion test in three conditions; normal in vitro culture growth using Hollander medium, lysed in distilled water and treated with metronidazole. MF stain showed similar growth profile pattern as Trypan Blue dye exclusion for identifying viable cells of T. vaginalis. Although, Trypan Blue dye exclusion test is ready made, rapid and widely used in laboratory as reliable viability assay, however, the limitation using Trypan Blue is the dye was unable to show internal morphological changes during the parasite's transition from being viable to non-viable. On day 3 where cultures peaked the correlation factor of both assays done to assess the viability of parasites harvested from the controls, metronidazole and distilled water treated parasites were more than 0·9 respectively. This confirms that MF staining does not only record permanently the morphological changes and retain internal structural details but also provides a reliable and rapid viability assay for the parasites. Therefore, in our study, Modified Field's stain may offer the researchers and laboratory technologists the opportunity to get the result on the same day and the most important thing is the ability to differentiate between viable and non-viable of T. vaginalis under three different conditions (normal culture, drug and distilled water condition). Modified Field's staining method enhanced the morphological identification of T. vaginalis compared to Trypan Blue dye exclusion.

Inactivation of Alicyclobacillus acidoterrestris spores in apple juice by supercritical carbon dioxide

We investigated the lethal effect of supercritical carbon dioxide (SC-CO 2; temperature: 65, 70 °C, pressure: 80, 100, 120 bar, time: 10–40 min) on Alicyclobacillus acidoterrestris spores (10 6–10 7 spores/ml) suspended in apple juice. A. acidoterrestris spores were completely inactivated by SC-CO 2 to undetectable levels in above 65 °C, 100 bar for 40 min and 70 °C, 80 bar for 30 min. The SC-CO 2 did not affect ( p > 0.05) the pH and ˚Brix of apple juice. In electron microscopic observations, the surface and internal morphological changes and extraction of intracellular materials of the treated spores were observed. Our results indicate that SC-CO 2 can effectively kill A. acidoterrestris spores in apple juice with no changes to the quality of the juice and also provides a complementary understanding of inactivation action of SC-CO 2.

Modeling of the inactivation of Salmonella typhimurium by supercritical carbon dioxide in physiological saline and phosphate-buffered saline

In this study, we used supercritical carbon dioxide (SC-CO 2) to inactivate Salmonella typhimurium suspended in physiological saline (PS) or phosphate-buffered saline (PBS). The colony forming activity of S. typhimurium was completely lost (i.e., 8-log reduction) under the following condition ranges: pressures of 80–150 bar, temperatures of 35–45 °C and 10–50 min treatment times. The microbial inactivation process had three distinct phases and was modeled by the modified Gompertz model. Generally, an increase in pressure at constant temperature, and an increase in temperature at a constant pressure, both enhanced S. typhimurium inactivation. When the cells were suspended in PBS rather than PS, the length of time for the complete inactivation significantly increased. We observed the surface and internal morphological changes of the cells by SEM and TEM, respectively. The extraction of proteinous substances, nucleic acids and outer membrane proteins into the suspension during SC-CO 2 treatment was also observed. Through SDS-PAGE analysis of the total proteins and major outer membrane proteins (OMPs) of SC-CO 2-treated cells, we found that a substantial amount of the total soluble proteins had converted into insoluble protein.

Developmental changes in in vivo cardiac performance in the moth Manduca sexta.

While an extensive literature on cardiovascular development exists for insects, almost all studies focus on in vitro preparations, and very few report on more than a single developmental stage. The present study examines in vivo cardiac performance in the intact, unanesthetized larvae, pupae and adults of the tobacco hornworm Manduca sexta. For all three stages, electrode pairs of fine steel wire were inserted subcuticularly at two dorsal abdominal locations. Impedance signals produced by contraction of the dorsal abdominal vessel (tube heart) were amplified and recorded. In addition to providing heart rate, a comparison of the relative timing of the signal from each electrode pair allowed the calculation of the propagation velocity and direction of heart contraction. Experimental treatments of intact animals included exposure to hypoxia and hyperoxia (21 %, 15 %, 10 %, 5 %, 0 % and 100 % O(2)), to hypercapnia (0 %, 4 %, 8 %, 16 %, 20 % and 24 % CO(2)), to temperature variation (10, 20 and 30 degrees C) and to 2 min periods of forced activity. The pattern of contraction of the dorsal abdominal vessel of M. sexta changed substantially with developmental stage. Larvae showed a relatively simple, invariably posterior-to-anterior pattern (mean rate 34.8+/-1.16 beats min(-)(1)). The heart rate pattern in pupal M. sexta displayed great variability in rate, amplitude and direction. Periods of regular heart beats (21.5+/-1.09 beats min(-)(1)) were frequently and irregularly interrupted by periods of cardiac arrests ranging from a few seconds to over 20 min. Adults showed a highly stereotypic but complex pattern, with periods of 'fast forward' (FF; rate 47.6+/-2.6 beats min(-)(1)), 'slow forward' (SL; 32.8+/-3.0 beats min(-)(1)) and 'reversed' (R; 32.2+/-2.4 beats min(-)(1)) beating. The contraction propagation velocity in larvae and pupae averaged 5. 52+/-0.36 and 2.03+/-0.11 cm s(-)(1), respectively. The SF, R and FF phases of the adults had average propagation velocities of 5.52+/-0. 51, 5.05+/-0.52 and 5.43+/-0.37 cm s(-)(1), respectively. Heart rate and contraction propagation velocity were remarkably resistant to ambient hypoxia and hypercapnia at all developmental stages, decreasing significantly only at 0 % O(2) or 24 % CO(2). As expected, the heart rates of all three developmental stages increased significantly with increasing temperature, with heart rate Q(10) values for larvae, pupae and adults of 2.33, 3.14 and 1.61, respectively, between 10 and 20 degrees C. Corresponding Q(10) values for these stages between 20 and 30 degrees C were 2.22, 2.03 and 2.29. Larval heart rates showed no significant response to forced activity induced by prodding. In contrast, adult heart rate increased nearly fivefold from 50.1 beats min(-)(1) during rest to 223.5 beats min(-)(1) after 1 min of prodding. The activity-induced tachycardia in adults ceased within 10-12 min. Patterns of cardiac contraction in larval, pupal and adult M. sexta were as dissimilar as their morphological appearances and revealed a gradation from simple to complex. These developmentally based distinctive cardiac patterns are undoubtedly related to developmental differences in both morphology and life-style. Larvae are anatomically 'homogeneous' compared with other stages, with no distinct head, thorax and abdominal region (or wings) that might require selective perfusion or drainage. The far more complex pattern of heart activity seen in pupae probably relates to the dramatic changes in internal morphology during this stage. Simultaneous degradation and synthesis of tissues throughout the body may expose the heart to numerous peptides or neurohormones that affect cardiac activity. In adult moths, the complex and repetitive pattern of cardiac activity is reflected in the previously described complexity of hemolymph movement, together with thermoregulatory capabilities in this species that depend on well-regulated hemolymph movements between the thorax, wings and abdomen.

The relationship between growth form and internal morphology in favositid corals

Growth form in Paleozoic colonial corals is commonly used as an indicator of paleoenvironmental conditions. However, this character was also influenced by genetic factors, and it must be recognized that aspects of internal morphology were significant in the development of external form. In favositids a primary control on growth form was exerted by rates of corallite divergence, offsetting, and vertical growth, since the shape of the corallum base and growth surface resulted largely from these factors. This relationship worked in both directions; modifications of external shape that were apparently related to environmental conditions are reflected by measurable changes in internal morphology. In any favositid the most efficient packing of corallites is hexagonal, but this arrangement was thrown out of equilibrium by corallite offsetting. Rate of offsetting was largely controlled by internal packing stress and thus by the degree of corallite divergence. Periodic offsetting is reflected by a bimodal corallite size distribution (dimetrism). The distribution of corallite shapes and sizes in different parts of a corallum is therefore a key indicator of mode of growth; growth form can be seen to have had an influence on characters that are commonly used as species discriminators.This study is based on analysis of serial sections of Paleofavosites subelongus (Savage) from the uppermost Ordovician to lowermost Silurian of the east-central United States. This species is highly variable in internal characters and the size range and type of corallite packing can differ substantially between coralla. The early part of each colony's astogeny played a major role in the development of growth form; specimens at either end of the variation continuum show contrasting modes of growth which generated different growth forms. In one mode, colonies produced broad bases through early axial offsetting and developed patterns of growth in which corallites expanded rapidly to mature sizes. Subsequent rates of offsetting were sufficiently high that dimetrism is common; such specimens most commonly have domical growth forms. In a second mode, colonies with lower rates of early axial offsetting have conical bases, a lower degree of dimetrism, and commonly bulbous forms.Patterns of subsequent growth of all coralla demonstrate the connection between internal and external characters. Periods of increased axial offsetting and higher rates of corallite expansion occurred in conjunction with phases of lateral colony expansion. Elsewhere in the colony, offsetting was also periodic but occurred predominantly at the edges of the axis and in colony margins; this pattern allowed the axial polyps to continue upward growth while shorter-lived polyps were generated to maintain lateral parts of the growth surface. Bursts of offsetting commonly occurred in bands with close-spaced tabulae and thickened corallite walls, and were sometimes associated with intervals of increased corallite mortality. Paleofavosites subelongus was apparently unable to produce offsets at the outermost colony margins and was thus confined to upwardly expanding growth forms with outcurved corallites. Serial sectioning of other species of Paleofavosites in which tabular forms predominate indicates that coralla with such shapes were able to generate abundant offsets along colony margins and could maintain axial regions with predominantly hexagonal corallites and low rates of offsetting.Although internal characters apparent early in astogeny set the basic mode of growth of each Paleofavosites subelongus colony, the subsequent growth form was influenced by numerous other factors, including reorientation during life, partial mortality of the growth surface, and probable changes in environmental conditions. In most populations one of the two modes of basal growth predominates, but populations with overlapping characters also occur. The growth pattern set down near the base of each corallum may be related to the environmental regime prevailing at and following the time of colony initiation, but may also reflect genetic differences within and between populations.