Length–weight relationships for Brazilian estuarine fishes along a latitudinal gradient

Ninety-nine length–weight relationships (LWR) were estimated for 70 bentho-demersal fish species captured in four Brazilian estuaries between latitudes 0°S and 25°S. LWR are published for the first time for 13 species. The allometry coefficient ( b ) of the LWR ( W = aTL ^b ) showed a median of 3.147. Positive allometry was dominant (64 of the 99 species x estuary cases), followed by isometry (28) and negative allometry (7). Twenty-two species were caught in two or more estuaries. In most cases (29 of 33 comparisons), the values of both regression parameters differed significantly among estuaries.     

Statistical model of variable allometric growth: otolith growth in Micropogonias furnieri(Actinopterygii, Sciaenidae)

The main objective of this study was to develop a statistical model for accurate estimates of relative growth. The method was based on identifying patterns of the residuals obtained from the Huxley's allometric equation. Three different approaches were applied: (1) growth with variable proportionality and constant allometry coefficient, (2) growth with constant proportionality and variable allometry coefficient and (3) distinct growth phases in which proportionality and allometry coefficients remained constant. The proposed statistical models were applied to the relationship of the otolith size and fish size of whitemouth croaker Micropogonias furnieri . The best fit was obtained when using approach (3). A change in the growth parameters was associated with the attainment of sexual maturity.     

Location of the isoleucine arrest point in CHO and 3T3 cells

An isoleucine arrest point in G1 was determined by two methods for CHO and 3T3 cells. In the first method the fraction of cells entering S after isoleucine deprivation was assessed by [³H]thymidine labelling and autoradiography. In the second method cells entering S after isoleucine deprivation were identified by double-label autoradiography using [³H] and [¹⁴C]thymidine. From the fraction of cells entering S, determined by the two methods, the arrest point in G1 (and entry into G0) is located within the last 40 min of G1.     

Phyletic size change and brain/body allometry: A consideration based on the African pongids and other primates

A problematic aspect of brain/body allometry is the frequency of interspecific series which exhibit allometry coefficients of approximately 0.33. This coefficient is significantly lower than the 0.66 value which is usually taken to be the interspecific norm. A number of explanations have been forwarded to account for this finding. These include (1) intraspecificallometry explanations, (2) nonallometric explanations, and (3) Jerison’s “extraneurons” hypothesis, among others. The African apes, which exhibit a lowered interspecific allometry coefficient, are used here to consider previous explanations. These are found to be inadequate in a number of ways, and an alternative explanation is proposed. This explanation is based on patterns of brain and body size change during ontogeny and phytogeny. It is argued that the interspecific allometry coefficient in African apes parallels the intraspecific one because similar ontogenetic modifications of body growth separate large and small forms along each curve. In both cases, body size differences are produced primarily by growth in later postnatal periods, during which little brain growth occurs. Data on body growth, neonatal scaling, and various lifehistory traits support this explanation. This work extends previous warnings that sizecorrected estimates of relative brain size may not correspond very closely to our understanding of the behavioral capacities of certain species in lineages characterized by rapid change in body size.     

3′:5′-Cyclic-nucleotide phosphodiesterase in the bovine pituitary gland

Cyclic-AMP phosphodiesterase activity in the homogenate of the anterior pituitary gland was 2-fold higher than that in the homogenate of the posterior pituitary, whereas cyclic-GMP phosphodiesterase activity was dominant in the posterior homogenate. There were two peaks of cyclic-AMP phosphodiesterase activity with different isoelectric points of 4.3 and 5.2. Fraction I had a molecular weight of 240 000 and a sedimentation coefficient of 6.2 S; fraction II had a molecular weight of 180 000 and a sedimentation coefficient of 3.1 S. Cyclic AMP hydrolytic activity in the supernatant of the posterior lobe corresponded to fraction I in the anterior lobe. Cyclic GMP hydrolytic activity in both the anterior and posterior lobes (activated by Ca²⁺ / calmodulin) had an isoelecteric point of 5.2, a molecular weight of 240 000 and a sedimentation coefficient of 6.2 S. Cyclic AMP and GMP hydrolytic activities in both the anterior and posterior lobes appeared in fraction I and did not separate when the preparations were mixed before electric focusing or sucrose density gradient procedures. Cyclic AMP hydrolytic activity in fraction II could be separated from cyclic GMP hydrolytic activity.     

3':5'-cyclic-nucleotide phosphodiesterase in the bovine pituitary gland

Cyclic-AMP phosphodiesterase activity in the homogenate of the anterior pituitary gland was 2-fold higher than that in the homogenate of the posterior pituitary, whereas cyclic-GMP phosphodiesterase activity was dominant in the posterior homogenate. There were two peaks of cyclic-AMP phosphodiesterase activity with different isoelectric points of 4.3 and 5.2. Fraction I had a molecular weight of 240 000 and a sedimentation coefficient of 6.2 S; fraction II had a molecular weight of 180 000 and a sedimentation coefficient of 3.1 S. Cyclic AMP hydrolytic activity in the supernatant of the posterior lobe corresponded to fraction I in the anterior lobe. Cyclic GMP hydrolytic activity in both the anterior and posterior lobes (activated by Ca2+/calmodulin) had an isoelectric point of 5.2, a molecular weight of 240 000 and a sedimentation coefficient of 6.2 S. Cyclic AMP and GMP hydrolytic activities in both the anterior and posterior lobes appeared in fraction I and did not separate when the preparations were mixed before electric focusing or sucrose density gradient procedures. Cyclic AMP hydrolytic activity in fraction II could be separated from cyclic GMP hydrolytic activity.     

Intrabasin variation in allometry coefficients of Lenkoran Capoeta capoeta gracilis (Keyserling, 1861) in the Gorganroud basin,southeast Caspian Sea,Iran

It is believed that streams of a basin may contribute to stream‐specific variation in allometry coefficients related to between‐habitat differences. To test intra‐basin variation of the allometry coefficients of Lenkorn Capoeta capoeta gracilis (Keyserling, 1861), a total of 1731 individuals were sampled in six streams of the Gorganroud basin (southeast Caspian Sea) between April and May 2008. Values of b ranged from 2.647 for males of Chelchai to 2.964 for females of Madarsou, indicating negative allometric growth for the fish in the basin. There were variations in the allometry coefficient among the considered groups, which can be interpreted as species’ response to different habitats. To the best knowledge of the authors, this study documents the comparative reference on variation of allometry coefficient of Capoeta capoeta gracilis in southeast Caspian streams.     

Growth of organ systems of Dentex dentex(L) and Psetta maxima(L) during larval development

Growth in volume of common dentex Dentex dentex and turbot Psetta maxima during larval development was studied by means of a quantitative histological method. A two‐phase pattern of volume increase was recorded for both species, turbot volume being always higher than dentex volume. During the first phase, the increase was small but during the second phase volume rose sharply from 22 days post hatch (dph) and 17 dph onwards in dentex and turbot, respectively. In dentex, the specific growth rate ( G ) of the whole larva as well as that of all the structures studied (nervous tissue, trunk musculature, digestive tract, liver, pancreas, spleen and thymus) was always higher during the second phase, whereas in turbot, only total volume of the larva, trunk musculature and nervous tissue had a higher G during the same period. The pattern of allometric growth of digestive organs was similar for both species. These organs showed an initial positive allometric growth that later became near‐isometric (digestive tract and liver) or negative (pancreas). In dentex, nervous tissue and trunk musculature showed near‐isometry throughout the period studied. In turbot, nervous tissue exhibited negative allometry and trunk musculature changed from negative to positive allometry. In both species studied, the highest allometry coefficients were recorded for digestive organs before the larva switched to strict exotrophy. This would indicate the importance of the development of these organs for survival.     

Sexual selection and the allometry of earwig forceps

Summary Positive intraspecific allometry, the tendency for large individuals to have relatively larger morphological traits, is thought to be more likely for secondary sexual traits than naturally selected traits. This is because secondary sexual traits are often used to signal individual quality and positive allometry should arise where the costs and/or benefits of signalling are size dependent. Here we examine the allometric relationships between forceps length, a sexually selected trait and elytra length, a naturally selected trait, in 42 species of earwig. Both forceps and elytra showed positive allometry. However, the degree of allometry was greater for forceps as predicted. If allometry arises due to sexual selection we would predict a greater degree of allometry in species with more exaggerated secondary sexual traits. Across species, the degree of forcep allometry did increase with forcep exaggeration. The relevance of positive allometry to reliable signalling is discussed.     

Identification of gamma-like DNA polymerase from sea urchin embryos.

A gamma-like DNA polymerase devoid of DNA polymerase-alpha and -beta activities was prepared from the nuclear fraction of blastulae of the sea urchin, Hemicentrotus pulcherrimus. The enzyme sedimented at the position of an approximate sedimentation coefficient of 3.3 S under high salt conditions by sucrose gradient centrifugation. An isoelectric point was determined to be pH 5.8. The enzyme activity was sensitive to sulfhydryl blocking reagents. Poly(rA) . oligo(dT)12--18 followed by poly(dA) . oligo(dT)12--18 was effectively utilized as a template-primer. From the above results, this polymerase seems to resemble the vertebrate DNA polymerase-gamma.     

Genital and body allometry in two species of noctuid moths (Lepidoptera: Noctuidae)

One‐size‐fits‐all and related hypotheses predict that static allometry slopes for male genitalia will be consistently lower than 1.0 and lower than the slopes for most other body parts (somatic traits). We examined the allometry of genitalic and somatic morphological traits in males and females of two species of noctuid moths, Spodoptera exigua (Hübner, [1808]) and Helicoverpa armigera (Hübner, [1808]). The relationship between genitalic traits and body size was generally strongly negative‐allometric in males but with no significant differences from 1.00 in females of the two species examined. However, in females, the slope of genital traits was also lower than the slopes for somatic traits. The relationship between somatic traits and the body size indicator was approximately isometric in most cases in males, except in four traits in S. exigua, in which the slopes showed slight negative allometry, and the hind tibia in H. armigera, in which the slope had positive allometry. However, in females, some somatic traits showed isometric and some other showed negative allometry in both species. The coefficients of variation (CV) for all structures in the males were low, not exceeding 10%. Genitalic traits showed significantly lower CV than somatic traits in males. In females, somatic traits showed lower CV than genitalic traits but with no significant difference in the H. armigera. Our observations of strongly negative allometry for genitalic traits in males are consistent with stabilizing selection on genital size and we suggest that male performance in interactions with females is the source of selection on male genital allometry. The difference in the degree of phenotypic variation between genitalic and somatic traits in the two studied species is attributed to the different developmental‐genetic architectures of these traits. Female genitalia showed a similar trend to the males, although the difference between genital and somatic traits was not significant in females. This finding suggests that selection is acting differently on male and female genitalia. Positive allometry of hind tibia in H. armigera may be a result of secondary sexual function.     

Composition and in vitro cytotoxicity of cellular infiltrates in rejecting human kidney allografts.

Xenogeneic immune RNA (I-RNA) extracted from the spleens and lymph nodes of guinea pigs previously immunized with a murine fibrosarcoma was able to convert normal mouse lymphocytes to effector cells specifically cytolytic to the same murine tumor in vitro. This effect of I-RNA was dose-dependent, and destroyed by treatment with RNase, but not with DNase or pronase. I-RNA was fractionated by ultracentrifugation on a 5–20% sucrose density gradient and the fraction capable of transferring cell-mediated cytotoxicity (CMC) was shown to have a sedimentation coefficient of 8–16 S. I-RNA was also fractionated by oligo(dT)-cellulose affinity chromatography and the active fraction was found to possess polyadenylic acid (poly(A)) sequences thus resembling messenger RNA. The immunological activity of the poly (A)-containing RNA fraction was tumor-specific and RNase-sensitive. In further experiments, I-RNA fractionated by sucrose density gradient ultracentrifugation was subsequently chromatographed. on an oligo(dT)-cellulose column. CMC was transferred only by the fraction which sedimented at 8–16 S and also contained poly (A).     

Discrimination of alternative male phenotypes in Scapanes australis (Boisduval) (Coleoptera: Scarabaeidae: Dynastinae)

Abstract  The palm pest Scapanes australis has been the object of considerable recent research to develop control measures that target male reproductive behaviour. This study investigated horn size scaling relationships and frequency distributions in two subspecies of S. australis for evidence of alternative male reproductive strategies. Indeed, a sigmoidal horn size allometry in both populations was detected as a significant vertical discontinuity by a piece-wise regression model, which indicates that distinct minor and major male phenotypes are expressed in both taxa. A non-linear regression algorithm showed that these subspecies differ significantly in two modelled parameters of horn allometry. A likelihood model was used for probabilistic discrimination of the alternative male phenotypes by estimating their ratios across the bimodal frequency distribution. The latter is intended to aid field investigation of the reproductive biology of S. australis by statistically discriminating the alternative male phenotypes on the basis of easily measured parameters in live samples.     

Testing the cranial evolutionary allometric ‘rule’ in Galliformes

Recent comparative studies have indicated the existence of a common cranial evolutionary allometric (CREA) pattern in mammals and birds, in which smaller species have relatively smaller faces and bigger braincases than larger species. In these studies, cranial allometry was tested using a multivariate regression between shape (described using landmarks coordinates) and size (i.e. centroid size), after accounting for phylogenetic relatedness. Alternatively, cranial allometry can be determined by comparing the sizes of two anatomical parts using a bivariate regression analysis. In this analysis, a slope higher or lower than one indicates the existence of positive or negative allometry, respectively. Thus, in those species that support the CREA ‘rule’, positive allometry is expected for the association between face size and braincase size, which would indicate that larger species have disproportionally larger faces. In this study, I applied these two approaches to explore cranial allometry in 83 Galliformes (Aves, Galloanserae), ranging in mean body weight from 30 g to 2.5 kg. The multivariate regression between shape and centroid size revealed the existence of a significant allometric pattern resembling CREA, whereas the second analysis revealed a negative allometry for beak size and braincase size (i.e. contrary to the CREA ‘rule’, larger galliform species have disproportionally shorter beaks than smaller galliform species). This study suggests that the presence of CREA may be overestimated when using cranium size as the standard measurement.     

mRNA for the plasminogen activator of the urokinase type: translation in oocytes of Xenopus laevis

Poly(A)+-RNA from human kidney and human embryonal lung fibroblasts fractionated by sucrose gradient centrifugation was translated in Xenopus oocytes. Assay for plasminogen-dependent fibrinolytic activity detected synthesis of secreted plasminogen activator and revealed the active fraction of poly(A)+-RNA with a sedimentation coefficient of approximately 23S. Translation products of the active fraction were immunoadsorbed by antiurokinase monoclonal antibodies immobilized on sepharose. Gel electrophoretic analysis of the protein products showed that the 23S fraction of poly(A)+-RNA from human kidney contains mRNA for single-chain urokinase-type plasminogen activator with apparent molecular weight of approximately 50 kDa.     

Properties of 5'-nucleotidase in rat heart sarcolemma

The activity of 5'-nucleotidase (5'-ribonucleotide phosphohydrolase, EC 3.1.3.5) was examined in membrane fractions isolated by hypotonic shock-LiBr treatment (fraction HL) and sucrose gradient separation (fraction S) of rat ventricle homogenate. The enzyme activity in these two fractions differed significantly in several respects. In fraction HL, 5'-nucleotidase had a high affinity for AMP (Km 35 microM), and ATP was a potent competitive inhibitor. In contrast, the 5'-nucleotidase displayed by fraction S showed a low substrate affinity (Km 130 microM) and less sensitivity to ATP. Treatment of membranes with trypsin and neuraminidase markedly stimulated 5'-nucleotidase in fraction HL, whereas only a modest effect was observed in fraction S. Exposure of the membranes to Triton X-100 resulted in a 60% and 10% increase in the enzyme activity in fractions HL and S, respectively. The characteristic activity ratios of 5'-nucleotidase at 200 microM relative to 50 microM AMP in fractions HL and S were modified by alamethicin in an opposite way and became identical. Although concanavalin A almost completely inhibited the 5'-nucleotidase activity in both membrane preparations at a concentration of 2 microM, Hill plots of the data on concanavalin A inhibition revealed a coefficient of 2.2 for fraction S and 1.1 for fraction HL. The differences in 5'-nucleotidase activity of the two membrane fractions are considered to be due to differences in the orientation of the vesicles of the sarcolemmal preparations. These results suggest that two distinct catalytic sites for 5'-nucleotidase are present at the intra- and extracellular surface of the rat heart sarcolemma.     

The allometric pattern of sexually size dimorphic feather ornaments and factors affecting allometry

The static allometry of secondary sexual characters is currently subject to debate. While some studies suggest an almost universal positive allometry for such traits, but isometry or negative allometry for nonornamental traits, other studies maintain that any kind of allometric pattern is possible. Therefore, we investigated the allometry of sexually size dimorphic feather ornaments in 67 species of birds. We also studied the allometry of female feathers homologous to male ornaments (female ornaments in the following) and ordinary nonsexual traits. Allometries were estimated as reduced major axis slopes of trait length on tarsus length. Ornamental feathers showed positive allometric slopes in both sexes, although that was not a peculiarity for ornamental feathers, because nonsexual tail feathers also showed positive allometry. Migration distance (in males) and relative size of the tail ornament (in females) tended to be negatively related to the allometric slope of tail feather ornaments, although these results were not conclusive. Finally, we found an association between mating system and allometry of tail feather ornaments, with species with more intense sexual selection showing a smaller degree of allometry of tail ornaments. This study is consistent with theoretical models that predict no specific kind of allometric pattern for sexual and nonsexual characters.     

Switching of metabolic-rate scaling between allometry and isometry in colonial ascidians

The metabolic rate and its scaling relationship to colony size were studied in the colonial ascidian Botrylloides simodensis. The colonial metabolic rate, measured by the oxygen consumption rate (V(O2) in millilitres of O(2) per hour) and the colony mass (wet weight M(w) in grams) showed the allometric relationship (V(O2) = 0.0412 M(w)(0.799). The power coefficient was statistically not different from 0.75, the value for unitary organisms. The size of the zooids and the tunic volume fraction in a colony were kept constant irrespective of the colonial size. These results, together with the two-dimensional colonial shape, excluded shape factors and colonial composition as possible causes of allometry. Botryllid ascidians show a takeover state in which all the zooids of the parent generation in a colony degenerate and zooids of a new generation develop in unison. The media for connection between zooids such as a common drainage system and connecting vessels to the common vascular system experienced reconstruction. The metabolic rate during the takeover state was halved and was directly proportional to the colonial mass. The scaling thus changed from being allometric to isometric. The alteration in the scaling that was associated with the loss of the connection between the zooids strongly support the hypothesis that the allometry was derived from mutual interaction among the zooids. The applicability of this hypothesis to unitary organisms is discussed.     

Developmental constraints on the evolution of wing-body allometry in Manduca sexta

Artificial selection on body size in Manduca sexta produced genetic strains with large and small body sizes. The wing-body allometries of these strains differed significantly from the wild type. Selection on small body size led to a change in the scaling of wing and body size without changing the allometry: the wings were smaller relative to the body, but to the same degree at all body sizes. Selection for large body size led to a change in allometry with a decrease in the allometric coefficient, wing size becoming progressively smaller relative to body as body size increased. When larvae were deprived of food so as to produce adults of a range of small body sizes, all strains retained the same allometric coefficient but showed an increase in the scaling factor. Thus individuals starved as larvae had a smaller adult body size but had proportionally larger wings than fed individuals. We analyzed the developmental processes that could give rise to this pattern of allometries. Differences in the relative growth of body and wing disks can account for the differences in the allometric coefficients among the three body size strains. The change in wing-body allometry at large body sizes was primarily due to an insufficient time period for growth. The available time period for growth of the wing imaginal disks poses a significant constraint on the proportional growth of wings, and thus on the evolution of large body size.     

20-Hydroxyecdysone accelerates the flow of cells into the G1 phase and the S phase in a male accessory gland of the mealworm pupa (Tenebrio molitor)

The cells of the bean-shaped accessory glands of mealworms proliferate through the first 7 days of the 9-day pupal stage. Immediately after larval-pupal ecdysis, 25-27% of the cells were in the G1 phase, 60-65% were in the G2 phase, and the balance were in S phase. Over the first 4 days of normal development, the S fraction gradually increased, to reach its highest level in the mid-pupa at the time of the major ecdysteroid peak (Delbecque et al., 1978). Thereafter, the S fraction declined until over 95% of the cells had accumulated in G2 on Day 8. When 0-day pupal glands were explanted into Landureau's S-20 medium for 6 days, the G1 fraction remained fairly constant (25-30%) while S and the G2 fractions fluctuated. On the first day in vitro, the G2 fraction declined and the S fraction rose. On the second day in basal media, the S fraction fell and G2 rose correspondingly until 70% of the cells reached G2 when cycling stopped on the third day. With addition of 20-hydroxyecdysone to 0-day cultures, the S fraction increased quite sharply. It remained large for all 6 days of the experiment in the continuing presence of hormone. A 1-day pulse of hormone produced a transient increase in S. We blocked cell cycling with hydroxyurea in a stathmokinetic experiment and showed that 20-hydroxyecdysone accelerated the flow of cells from the G2 phase to the G1 phase by 2.5-fold. An increase in the G1 fraction was detected within 10 hr of hormone administration and the effect was dose-dependent with an ED50 of 5 X 10(-7) M for 20-hydroxyecdysone. We conclude that 20-hydroxyecdysone acts at a control point in the G2 phase. Incubation of the glands with 20-hydroxyecdysone for only 30-60 min followed by washout stimulated the flow from G2 to G1 and the effect persisted after transfer of the tissues to hormone-free media. Dose-dependent stimulation also occurred with ponasterone A (ED50 3 X 10(-9] but not with cholesterol.