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PubMed1977

The relationship between growth, developmental stage and postamputation age of the regeneration blasterma of the newt, Notophthalmus viridescens.

The growth of the regeneration blastema of the newt forelimb has been quantitated and analyzed as a function of postamputation age, developmental stage, animal weight, animal length, and cross sectional diameter of the blastemal base in both the anteroposterior and dorsoventral dimensions. Correlation coefficients computed for these variables show that growth of the regenerate in both length and volume is more closely correlated with developmental stage than postamputation age. In addition, the results show a linear relation between the loge (regenerate length) and developmental stage, and between regenerate length and volume. Thus, length can be used to assess growth of the regenerate according to a developmental rather thana chronological time scale. There were no significant correlations between regenerate length or volume and animal length, animal weight or cross sectional dimensions of the blastemal base. These results show that one can use a randomly selected population of animals and study the growth of the regeneration blastema by relating to a developmental time scale through a logarithmic transformation of the linear growth data.

Amputation, Surgical↗
PubMed1980

Light and electron microscopic study on developmental stages of Babesia canis within the gut of the tick Dermacentor reticulatus.

The initial developmental stages of Babesia canis within the gut of the vector tick, Dermacentor reticulatus, were studied by means of light and electron microscopy. Large quantities of varying "spiky-rayed" stages and few ovoid stages without any protrusions were observed after lysis of the engorged canine erythrocytes. The transformation of spherical erythrocytic stages into "spiky-rayed" forms was initiated inside the intact erythrocytes. The significance of all developmental stages in a hypothetical life cycle of Babesia species is discussed.

Animals↗
PubMed1981

Protein and nitrate content of lemna sp. As a function of developmental stage and incubation temperature.

Lemna protein per frond and per root increases with developmental stage until plants are at least two generations old. Protein per frond, per root, and per unit dry weight is greater in plants grown at 23.9 C than at 18.3 C. More protein is found in fronds than in roots, and more nitrate occurs in roots than in fronds. Nitrate per root increases with developmental stage and is higher (per root) in plants grown at 23.9 C than in those grown at 18.3 C. The distribution of generations within a growing population is constant for at least eight doubling times. Whether populations multiply slowly at 15.6 C or more rapidly at 23.9 C, fronds which have not yet produced progeny form 62% of the population; fronds which are one generation old form 24% of the population; and fronds which are two generations old form 9% of the population.

Journal Article↗
PubMed2005

Expression patterns of three heat shock protein 70 genes among developmental stages of the red flour beetle, Tribolium castaneum (Coleoptera: Tenebrionidae).

Three genes were identified encoding heat shock protein 70's in Tribolium castaneum (Herbst) and they were tentatively named as tchsp70 I, tchsc70 II, and tchsp70 III. Comparison of deduced amino acid sequences of tchsp70 I and tchsc70 II showed 99% identity. However, the amino acid sequence of tchsp70 III was only 58.5% identical to those of tchsp70 I and tchsc70 II. Stage-specific expression patterns of the tchsp70 were investigated in young larvae, old larvae, pupae, and adults of T. castaneum exposed for 1 h to 23 degrees C (control) or 40 degrees C (heat-shock). Northern blot and real-time quantitative PCR analyses were carried out to determine mRNA levels in each life stage. Transcripts of all three genes were detected by Northern blotting, and the sizes were 2.4- 2.2-, and 2.3-kb for tchsp70 I, tchsc70 II, and tchsp70 III, respectively. A 1.1- to 2.0-fold increased expression of tchsp70 I mRNA was found in heat-shocked developmental stages compared with the control. The expression of tchsc70 II mRNA among developmental stages was similar between heat-shocked and control insects, and the expression of tchsp70 III mRNA varied among developmental stages. Results suggest that the expression of tchsp70 I gene is heat-inducible, tchsc70 II is constitutive, and tchsp70 III is developmentally regulated in T. castaneum.

Amino Acid Sequence↗
PubMed2006

Effect of embryo developmental stage and culture conditions on number and quality of ovine in vitro produced blastocysts.

This study evaluated the final output and quality of in vitro produced blastocysts derived from in vivo recovered sheep embryos cultured at various early developmental stages to blastocyst. A total of 270 embryos were recovered from the oviduct, at different days of the early luteal phase, and were classified into three different developmental stages: 2- to 4-cell (n = 93); 5- to 8-cell (n = 92) and 9- to 12-cell (n = 85). The effect of culture conditions was studied, at the same time, by randomly allocating the embryos to one of four groups: three groups of culture with fresh oviduct monolayers (2, 4 and 5 days old) and a fourth group with 2-day monolayers derived from frozen-thawed oviduct cells. Two control groups were established: first, embryos cultured in semi-defined medium (n = 29) and, second, blastocysts obtained in vivo and cryopreserved (n = 43). Influence on blastocyst yield of embryo developmental stage at the start of culture was statistically significant (p < 0.001). Two- to four-cell embryos showed a significantly lower developmental rate (67.7%) than the 5- to 8-cell (83.6%; p < 0.001) and 9- to 12-cell groups (90.5%; p < 0.0001) and lower quality in terms of blastocyst cryotolerance (56.0 vs. 83.7%; p < 0.005). There were no detected effects relating to the age or handling of the monolayer on the embryo developmental rate, but the day of blastocyst appearance was different between embryos cultured on monolayers derived from fresh or frozen-thawed cells (p < 0.0001); the main influence was on the group of 9- to 12-cell embryos (p < 0.0001). Current results confirm the temporal sensitivities of sheep embryos to in vitro culture, regardless of the culture conditions.

Animals↗
PubMed1999

Developmental stages in the human thymus.

The thymus is populated by hematopoietic cells that have the capacity to develop into at least three different hematopoietic lineages, T, NK and dendritic cells. While developing into T cells these cells pass a series of developmental stages that can be discriminated on the basis of expression of a number of antigens. The availability of a myriad of monoclonal anti- bodies against human differentiation antigens has permitted a detailed analysis of the various cellular stages in the human thymus. This analysis not only comprised investigation of molecular but also of functional features of purified thymocyte subsets, since more recently assays were set up that allowed investigation of the hematopoietic precursor activities of human thymic progenitor cells. Here we review the current status of knowledge with regard to early developmental stages in the human thymus. In addition, we discuss recent data on later developmental stages, in particular concerning positive selection and maturation of T cells.

Antigens, Differentiation↗
PubMedDate not supplied

Determining the sensitive developmental stages of intersex induction in medaka (Oryzias latipes) exposed to 17 beta-estradiol or testosterone.

Certain environmentally persistent compounds can adversely affect reproduction by acting as steroid hormone agonists or antagonists. The goal of the present study was to determine the developmental stage most susceptible to exogenous hormone (estradiol and testosterone) exposure using a small teleost model. In the first (pilot study) of two experiments, medaka (Oryzias latipes), at varying developmental stages, were bath-exposed to 5 micrograms/l 17 beta-estradiol for 24 h. At 5 months of age, fecundity, fertility and embryo and larval viability (reproductive success) were investigated in control and exposed groups. Fish at 1, 1.5, 2 and 5.5 months of age were also sampled, processed and examined histologically for gonadal alteration. No significant differences in mortality, gonadal morphology, body weight, sex-ratio or time to maturity were seen between control and exposed fish. At 5 months, however, when exposure groups were compared to controls, significant differences were seen in reproductive success and viability of offspring. A second experiment exposed embryo stage 10, and 1-, 7- and 21-day-old larvae for 6 days to 15 micrograms/l 17 beta-estradiol or 100 micrograms/l testosterone. No significant differences were seen at 5 months in mortality, body weight, or time to sexual maturity. However, sex-ratios were significantly biased toward female in the stage 10, 1- and 7-day post-hatch estradiol exposure groups. No significant changes in sex-ratio were associated with testosterone exposure at any developmental stage. Further, intersex gonads were observed in fish from all groups exposed to 15 micrograms/l estradiol. Only those fish exposed as newly hatched fry or at 1 week post-hatch displayed intersex gonads following 100 micrograms/l testosterone exposure. Data from these experiments show that newly hatched fry are that life stage most sensitive to hormone exposure and the most appropriate to use in determining effects of known endocrine-disrupting compounds.

Animals↗
PubMed1993

Differential expression of principal sigma factor homologues of Streptomyces aureofaciens correlates with the developmental stage.

In previous experiments, Streptomyces aureofaciens has been shown to contain four genes hrdA, hrdB, hrdD, and hrdE, encoding polypeptides very similar to principal sigma factors of RNA polymerase. Two apparent tandem promoters were identified for each of the hrdA, hrdB and hrdD genes by S1 nuclease mapping using RNA prepared of S. aureofaciens in various developmental stages. Under all the conditions studied, tandem promoters of each gene differed significantly in their respective strengths. Transcription from the hrd promoters depended on developmental stage. While hrdB is transcribed from both promoters in all developmental stages, both tandem promoters of the hrdD gene are active only in vegetative stage and transcription of the hrdA tandem promoters temporally correlates with the aerial mycelium formation. In addition to a promoter, hrdB-P2, which lies upstream of the open reading frame, the hrdB gene, proposed to encode functional principal factor, appeared to contain at least one internal promoter, hrdB-P1. Activity of all promoters was consistent with S1 mapping experiments after insertion of promoter-bearing DNA fragments to promoter-probe vectors pIJ486 and pARC1. The results implicate temporally different expression of the hrd genes during the differentiation of S. aureofaciens.

Amino Acid Sequence↗
PubMed1986

Expression of myosin isozymes during the developmental stage and their redistribution induced by pressure overload.

Cardiac muscles contain at least two isozymes--referred to as alpha(HC alpha) and beta(HC beta)--of the myosin heavy chain. The proportional ratio of these isozymes varies depending upon the developmental stage and the physiological and/or the hormonal milieu of the cell. Using monoclonal antibodies (MoAb) specific for human cardiac HC alpha and HC beta, we have examined the expression of these isozymes in fetal through adult cardiac tissues and investigated whether isozymic redistribution occurs in pressure overloaded human ventricles. We found that although HC alpha was expressed in the atrium from the early embryonic stage, in embryonic ventricular myofibers, only HC beta was expressed without expression of HC alpha, but some myofibers replace HC beta by HC alpha after birth, and these HC alpha containing ventricular myofibers were found to be decreased by pressure overload, which suggested that isozymic redistribution from HC alpha to HC beta also occurred in the ventricles, as well as the atrium. In addition, we also found two subtypes of HC beta (beta 1, beta 2) in the human heart. In the ventricle, both beta 1 and beta 2 was present in all myofibers; in contrast, some myofibers contained beta 1 or beta 2 or both with or without expression of HC alpha in the atrium. beta 1 and beta 2 were distinctive in their expression during the developmental stage, since beta 1 was present in the embryonic heart from the early developmental stage, whereas beta 2 was not present in the early embryonic heart, but began to be expressed in the late embryonic stage.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

An erythroid-specific, developmental-stage-independent enhancer far upstream of the human "beta-like globin" genes.

We have identified an erythroid-specific enhancer element far upstream of the human "beta-like globin" genes, at 10.2-11.0 kilobases 5' of the embryonic epsilon-globin gene, and thus at 53-54 kilobases 5' of the adult beta-globin gene. It is capable of enhancing the expression of a cis-linked test gene by up to 300-fold. This enhancer element is apparently developmental-stage-independent, as it is functional at the embryonic and the adult developmental stages in erythroid cells that are expressing the respective beta-like globin genes. The enhancer and globin promoter sequences work in synergy and are capable of conferring on a cis-linked gene the high transcriptional efficiency (enhancer function), erythroid specificity (enhancer and promoter functions), and developmental-stage specificity (promoter function) that are characteristic of the in vivo transcription of the beta-like globin genes in erythroid cells.

Age Factors↗
PubMed2004

Effects of developmental stage, embryonic interferon-tau secretion and recipient synchrony on pregnancy rate after transfer of in vitro produced bovine blastocysts.

Three separate trials of bovine embryo transfers were performed consisting of 32, 41 and 33 transfers, respectively, to examine the effects of (a) the developmental stage of in vitro-derived blastocysts, (b) the amount of interferon-tau (IFN-tau) they secreted during culture and (c) the cyclic stage of the recipient at the time of transfer on the probability of establishment of pregnancy. One blastocyst was transferred into the ipsilateral uterine horn to the CL. At the time of transfer, blastocysts were classified into one of three developmental stages (early blastocyst, blastocyst and expanded blastocyst) and the cyclic stage of each cow was assessed (-12 h, on time, +12 h, +24 h, >24 h). Prior to the second and third trials, blastocysts were individually cultured for 24 h in 50 microl medium droplets and the IFN-tau concentration in the droplet was determined. Logistic regression analyses revealed that expanded blastocysts had a significantly higher likelihood of establishing pregnancy (p = 0.009), and that there was a significant interaction with the cyclic stage of the recipient in this group with lower rates of pregnancy resulting from decreasing synchrony with the recipient (p = 0.033). IFN-tau secretion during culture was significantly higher in expanded blastocysts than in the other two groups (p < 0.05). A significant effect of the pre-transfer level of IFN-tau secretion was found only in the 'Blastocyst' group where transfer of embryos with lower IFN-tau production prior to transfer resulted in higher pregnancy rates (p = 0.047). These results demonstrate that IFN-tau secretion may be a useful tool to predict pregnancy outcome, but only within certain developmental stages.

Animals↗
PubMed1987

Localization and quantitation of 125I-epidermal growth factor binding in mouse embryonic tooth and other embryonic tissues at different developmental stages.

We have shown earlier that epidermal growth factor (EGF) inhibits morphogenesis and cell differentiation in mouse embryonic teeth in organ culture. This inhibition depends on the stage of tooth development so that only teeth at early developmental stages respond to EGF (A-M. Partanen, P. Ekblom, and I. Thesleff (1985) Dev. Biol. 111, 84-94). We have now studied the quantity and pattern of EGF binding in teeth at various stages of development by incubating the dissected tooth germs with 125I-labeled EGF. Although the quantity of 125I-EGF binding per microgram DNA stays at the same level, localization of 125I-EGF binding by autoradiography reveals that the distribution of binding sites changes dramatically. In bud stage the epithelial tooth bud that is intruding into the underlying mesenchyme has binding sites for EGF, but the condensation of dental mesenchymal cells around the bud does not bind EGF. At the cap stage of development the dental mesenchyme binds EGF, but the dental epithelium shows no binding. This indicates that the dental mesenchyme is the primary target tissue for the inhibitory effect of EGF on tooth morphogenesis during early cap stage. During advanced morphogenesis the binding sites of EGF disappear also from the dental papilla mesenchyme, but the dental follicle which consists of condensed mesenchymal cells surrounding the tooth germ, binds EGF abundantly. We have also studied EGF binding during the development of other embryonic organs, kidney, salivary gland, lung, and skin, which are all formed by mesenchymal and epithelial components. The patterns of EGF binding in various tissues suggest that EGF may have a role in the organogenesis of epitheliomesenchymal organs as a stimulator of epithelial proliferation during initial epithelial bud formation and branching morphogenesis. The results of this study indicate that EGF stimulates or maintains proliferation of undifferentiated cells during embryonic development and that the expression of EGF receptors in different organs is not related to the age of the embryo, but is specific to the developmental stage of each organ.

Animals↗
PubMed1998

Plasmodium falciparum: purification of the various gametocyte developmental stages from in vitro-cultivated parasites.

Cultivated Plasmodium falciparum gametocytes reach maturity in vitro in approximately 14-16 days, during which they pass through five morphologically distinct developmental stages. Purification of the earlier developmental stages has not been previously reported. We have modified the standard discontinuous Percoll gradient method for the separation of stage IV and V gametocytes to obtain enriched preparations of those and the earlier P. falciparum gametocyte stages. In contrast to the stages II, III, and IV, the mature stage V gametocytes from our gradient readily transformed into gametes. Such preparations may be useful in research studies on the mechanisms that underlie gametocytogenesis.

Animals↗
PubMed2000

Characterization of the developmental stages of sucking in preterm infants during bottle feeding.

It is acknowledged that the difficulty many preterm infants have in feeding orally results from their immature sucking skills. However, little is known regarding the development of sucking in these infants. The aim of this study was to demonstrate that the bottle-feeding performance of preterm infants is positively correlated with the developmental stage of their sucking. Infants' oral-motor skills were followed longitudinally using a special nipple/bottle system which monitored the suction and expression/compression component of sucking. The maturational process was rated into five primary stages based on the presence/absence of suction and the rhythmicity of the two components of sucking, suction and expression/compression. This five-point scale was used to characterize the developmental stage of sucking of each infant. Outcomes of feeding performance consisted of overall transfer (percent total volume transferred/volume to be taken) and rate of transfer (ml/min). Assessments were conducted when infants were taking 1-2, 3-5 and 6-8 oral feedings per day. Significant positive correlations were observed between the five stages of sucking and postmenstrual age, the defined feeding outcomes, and the number of daily oral feedings. Overall transfer and rate of transfer were enhanced when infants reached the more mature stages of sucking. We have demonstrated that oral feeding performance improves as infants' sucking skills mature. In addition, we propose that the present five-point sucking scale may be used to assess the developmental stages of sucking of preterm infants. Such knowledge would facilitate the management of oral feeding in these infants.

Bottle Feeding↗
PubMed1999

Expression of five steroidogenic genes including aromatase gene at early developmental stages of chicken male and female embryos.

In the course of avian embryo development, estrogen has been indicated to play a key role in gonadal differentiation by the inhibition of aromatase (P-450arom) that synthesizes estrogen from androgen. Biosynthesis of estrogen requires not only P-450arom but also other enzymes for a steroidogenic pathway. To elucidate gonadal differentiation, the steroidogenic pathway should be studied comprehensively in the early developmental stages including that of sex differentiation. Therefore, in the present study, the expressions of the steroidogenic genes, P-450scc, 3beta-HSD, P-450c17, 17beta-HSD and P-450arom, were measured at the developmental stages (days 2-9 of incubation) of chicken embryos by quantitative RT-PCR. Transcripts for all the genes studied, except for P-450arom were detected in all the developmental stages examined, indicating that mRNAs for the steroidogenic enzymes required to convert cholesterol to androgens are present in the avian embryo before gonadal differentiation. In contrast, P-450arom mRNA was detected in female embryos during days 5-9 of incubation but not in male embryos throughout incubation. The onset of P-450arom gene expression at day 5 coincides with the stage of gonadal differentiation, corroborating the role of estrogen in the process of gonadal differentiation in chicken.

Animals↗
PubMed2007

Lamellar pro-inflammatory cytokine expression patterns in laminitis at the developmental stage and at the onset of lameness: innate vs. adaptive immune response.

REASONS FOR PERFORMING STUDY: Recent research has indicated that inflammation plays a role in the early stages of laminitis and that, similar to organ failure in human sepsis, early inflammatory mechanisms may lead to downstream events resulting in lamellar failure. Characterisation of the type of immune response (i.e. innate vs. adaptive) is essential in order to develop therapeutic strategies to counteract these deleterious events. OBJECTIVES: To quantitate gene expression of pro-inflammatory cytokines known to be important in the innate and adaptive immune response during the early stages of laminitis, using both the black walnut extract (BWE) and oligofructose (OF) models of laminitis. METHODS: Real-time qPCR was used to assess lamellar mRNA expression of interleukins-1beta, 2, 4, 6, 8, 10, 12 and 18, and tumour necrosis factor alpha and interferon gamma at the developmental stage and at the onset of lameness. RESULTS: Significantly increased lamellar mRNA expression of cytokines important in the innate immune response were present at the developmental stage of the BWE model, and at the onset of acute lameness in both the BWE model and OF model. Of the cytokines characteristic of the Th1 and Th2 arms of the adaptive immune response, a mixed response was noted at the onset of acute lameness in the BWE model, whereas the response was skewed towards a Th1 response at the onset of lameness in the OF model. CONCLUSIONS: Lamellar inflammation is characterised by strong innate immune response in the developmental stages of laminitis; and a mixture of innate and adaptive immune responses at the onset of lameness. POTENTIAL RELEVANCE: These results indicate that anti-inflammatory treatment of early stage laminitis (and the horse at risk of laminitis) should include not only therapeutic drugs that address prostanoid activity, but should also address the marked increases in lamellar cytokine expression.

Animals↗
PubMed2001

Ecophysiological Characterization of Rhizosphere Bacterial Communities at Different Root Locations and Plant Developmental Stages of Cucumber Grown on Rockwool.

Bacterial communities from the rhizosphere of cucumber were characterized with respect to growth rates and carbon source utilization, in order to develop a selection strategy for biocontrol agents against Pythium aphanidermatum. Rhizosphere samples were collected from different root regions (root tips, the root base, and the intermediate region where lateral roots emerge) and developmental stages (the seedling, vegetative, and generative stage) from plants cultivated on reused rockwool. By colony counts on 1/10 strength TSA on subsequent days after plating, percentages of fast- and slow-growing isolates (i.e., forming visible colonies within 2 days, or after 3 or more days, respectively) were determined for each rhizosphere sample. At all plant developmental stages, root tips had the highest percentages of fast growing isolates, and root bases the lowest. During plant growth, the relative amounts of slowly growing bacteria increased. Community-level carbon source utilization was determined for the different rhizosphere samples with Biolog GN plates. Principal component analysis showed that rhizosphere samples from different developmental stages and root locations had distinct carbon source utilization patterns. Communities from root tips of seedlings showed the highest utilization of several monosaccharides. Communities from tips and intermediate regions of plants in the vegetative stage utilized relatively many amino acids and several organic acids, and in the generative stage, more di- and polysaccharides were used. Root base samples scored low with respect to carbon source utilization, except for some disaccharides. From the different rhizosphere samples, 826 bacteria, randomly collected from 1/10 strength TSA plates, were screened on the utilization of 9 carbon sources. The 9 selected carbon sources were chosen because they are reported to occur in the rhizosphere, to be used by the zoospores of Pythium in the infection process, or appeared to be discriminant in the analysis of community-level carbon source utilization performed in this study. It appeared that monosaccharides (glucose and fucose), amino acids (alanine and asparagine), and organic acids (galacturonic, succinic, and linoleic acid) were used for growth mainly by bacteria from the root tips, and to a lesser extent from the intermediate region, of young plants. Disaccharides were predominantly utilized by isolates from plants in the vegetative stage. Overall, the results indicated that growth rates and carbon source utilization reflect the adaptation of bacteria to the rhizosphere environment. The possibility of using these characteristics to screen for rhizosphere competent biocontrol agents that compete for substrates with P. aphanidermatum is discussed.

Journal Article↗