Early Adult Development Research Articles

Growing in Wisdom in Christian Community: Toward Measures of Christian Postformal Development

On the basis of theoretical work reported elsewhere, scales were developed with the goal of measuring some phenomena associated with Christian postformal thought development. These scales were used in 3 studies. The first examined scale intercorrelations; the second compared scores on the scales between evangelical and nonevangelical college samples; the third was a 4-year longitudinal study of a group of evangelical college students. Significant differences in scale scores were found in the evangelical and nonevangelical college samples and across the 4 years of the longitudinal study, which showed that individualism and relativism are not necessary concommitants of maturing cognitive development within the Christian community, calling into question the reliance on exclusively secular theories for understanding early adult development of Christians.

Characterization and temporal aspects of haemolymph juvenile hormone esterase in adult cockroach, Periplaneta americana

Daily variations in the in vitro haemolymph juvenile hormone esterase activity (hJHE) of adult male and female Periplaneta americana were monitored over a 2 week period from the time of adult emergence and throughout the first reproductive cycle of the adult female. Kinetic analysis of hJHE from females indicated an apparent K m JH III of 5.59±1.75 μ m ( V max=140 pmol JH III hydrolysed h −1 per μl haemolymph). In females the mean rate of JH III metabolism in diluted haemolymph shortly after emergence was 27.5±1.5 pmol h −1 μl −1 ( n=16) and remained relatively low (16–32 pmol h −1 μl −1) over much of early adult development. Activity remained at this level during the first two days of the 4 day reproductive cycle, but showed a much increased broad peak of activity (74–93 pmol h −1 μl −1) at 60–72 h post-extrusion. This peak lags behind the whole body JH titre peak, which could suggest that elevated levels of JH III may bring about the induction of JH esterase(s). A different pattern of JHE activity was observed in adult males. hJHE rates in males at emergence were almost twice as high (81.5±15.8 pmol h −1 μl −1, n=16) as those found in females at this time, but thereafter showed a downturn to moderate levels (44–68 pmol h −1 μl −1) that were maintained for the remainder of the study. Rapid (FPLC) DEAE–sepharose ion exchange chromatography, ultrafiltration and fast-flow superose gel filtration chromatography were employed to achieve an efficient partial purification (166-fold) of the hJHE from cell-free plasma of reproductively active female P. americana 48–72 h post-ootheca extrusion. Gel filtration and SDS–polyacrylamide gel electrophoresis (PAGE) revealed an enzyme having apparent molecular mass of between 60 and 70 kDa, whilst non-denaturing PAGE and iso-electrofocusing resolved a single acidic enzyme peak with a pI of 4.9.

The Call of Wisdom: Adult Development within Christian Community, Part II: Towards a Covenantal Constructivist Model of Post-Formal Development

Certain teachings in the Bible point to the need for post-formal thought structures. However, Christian post-formal development has features that distinguish it from modern post-formal development, primarily because of the divine and social dimensions of thought-formation in the Christian framework. From the Christian standpoint, true human understanding is composed by humans but derived from God; it is reconstructive. True human understanding is also rooted in the context of the Christian's communal, and personal, covenantal relation with God. Hence, the materials relevant to a Christian theory of early adult development point to a model termed “covenantal constructivism.”

Growth of single proglottides during early adult development of Hymenolepis nana.

The growth of individual proglottides of Hymenolepis nana has been studied by measuring the width and length of the proglottides between days 3 and 8 post-infection in mice. Two sets of measurements were obtained. The first involved proglottides immediately posterior to the point of proglottis formation and proglottides at particular stages of development. For the second set, measurements were made of proglottides at certain positions in the worm, specifically the 20th, 100th and 200th proglottides, as counted from the posterior end of the worm. For proglottides at different stages in development, the width of a particular stage was greater in the later days of infection, while the length was almost constant. The length of newly-formed proglottides varied only slightly with time despite differences in the width and in the 3-fold increase in proglottis production that occurs between days 3 and 8 post-infection. The width of the 20th, 100th and 200th proglottides followed parallel growth curves that coincided with each other after an appropriate shift along the time axis. The more anterior the position of the proglottis, the greater was the width at the time of proglottis formation, and so its growth began later on the common growth curve. Growth in length of the 20th proglottis was at first faster than the 100th and 200th proglottides, but later slowed down to a level comparable with them, and the growth curves for the length of the three proglottides were very similar to each other. The rates of growth in the volume of the three proglottides were also estimated. The results are also discussed in relation to other approaches to the study of tapeworm growth and to factors that may be responsible for the growth patterns observed.

Dynamics of hydrocarbon biosynthesis and transport to the cuticle during pupal and early adult development in the cabbage looper Trichoplusia ni (Lepidoptera: Noctuidae)

Hydrocarbons are synthesized at specific time periods during pupal development: between 40–90 h after the pupal molt and 10–12 h before adult emergence, with very low levels of synthesis at other times. These newly synthesized hydrocarbons remain internal and are not deposited on the pupal cuticle. Methylalkanes are synthesized between 40–90 h after the pupal molt while n- alkanes appear at the end of the pupal stage. Hydrocarbon is synthesized by the tissue associated with the pupal case and it is then transferred to an, as yet undetermined, internal storage site. Approximately 5 h before the adult emerges, methylalkanes are deposited on the adult cuticle and deposition continues, although at a slower rate, during the following 24 h. n- Alkanes appear on the adult cuticle 1 day after emergence. Trichoplusia ni does not reabsorb its cuticular hydrocarbons prior to molting, but rather discards them with the cast skin. Internal hydrocarbons synthesized during the previous stadium are deposited on the cuticle of the new instar upon molting. Adult males and females incorporate both [1- 14C]acetate and [1- 14C]propionate into hydrocarbons but no newly synthesized hydrocarbons are deposited on the adult cuticle.

An analysis of the secretions of the male accessory reproductive gland of the African migratory locust

The male accessory reproductive gland of the mature adult Locusta has been examined during early adult development. The protein content of the accessory gland increased markedly over the first 15 d...

The effects of precocene II on early adult development in male Locusta

Haemolymph protein synthesis and the accumulation of protein in haemolymph and accessory reproductive gland of normal adult male locusts were compared to that of males treated with precocene II. The precocene-treated insects showed a lower level of protein synthesis in both the fat body (source of haemolymph protein) and accessory reproductive gland. Topical application of juvenile hormone reversed the effects of precocene treatment. It would appear that the observed effects are the result of a reduction in juvenile hormone titre in the treated animals.

Sequence of development of iron deficiency in the rat

This study was designed to determine the interrelationships among storage iron, transport iron, and iron compounds that serve known physiological functions (Hb, myoglobin, and cytochrome c) during the gradual progression of dietary iron deficiency. These three categories of iron compounds are generally considered to become depleted in three corresponding, sequential stages. However, there is scattered evidence of substantial overlap between these stages in man. The presence of such overlap may prove pertinent to the interpretation of laboratory tests used in the diagnosis of iron deficiency. The rat was used as an experimental model to allow more complete evaluation of the interrelationships between the stages of iron deficiency than would be possible in man. Rats were given diets containing 2, 6 and 50 mg iron/kg diet during early adult development, between 36 and 90 days of age. The iron-deficient diets (2 and 6 mg iron/kg diet) resulted in decreases in hematocrit and in muscle and intestinal cytochrome c well before storage iron in the liver and spleen was exhausted. The results in the rat model may help to explain why there is not a consistent pattern of laboratory abnormalities in individuals with chronic, mild dietary iron deficiency.

Protein synthesis during early adult and second pupal development in the silkmoth, Antheraea polyphemus

Experiments were performed to measure protein synthesis in wing epidermal cells during early pharate adult and second pupal development. The period for juvenile hormone (JH) determination of second pupal wings occurred between 18 and 24 hr after injection of 20-hydroxyecdysone (20-HE) plus JH. Between 12 and 24 hr, [ 35S]-methionine incorporation remained relatively constant in pupae that had received exogenous hormones (either 20-HE alone or 20-HE and JH) and there was no significant difference between these groups. For 12–48 hr after hormone injection, no variation in banding patterns specific to a particular hormone treatment were evident by one-dimensional electrophoresis, despite dramatic changes in protein content at this time. At 3–6 days, differentiation specific protein bands were detected. Two dimensional electrophoresis was then used to examine more closely specific proteins synthesized during the 18–24 period, when developmental reprogramming occurred. At 24 hr, the synthesis of two clusters of proteins and a single protein were detected in samples from 20-HE treated animals but were not detected in samples from animals injected with 20-HE plus JH. No JH-specific proteins were detected. The adult specific proteins may be the product of events concerning the mechanisms of adult commitment.

Rate of rRNA synthesis during metamorphosis of the blowfly, Calliphora vicina

The rate of rRNA biosynthesis during metamorphosis of the blowfly Calliphora vicina has been determined by measuring the short-term incorporation of injected 3H-uridine into rRNA, and the specific activity of the soluble (precursor) UTP pool. The highest rate of rRNA synthesis (106 μg rRNA/insect/day) occurs in the mature larva. This rate declines during early pharate adult development to become approximately constant at 46 μg/insect/day up to adult emergence. The good agreement between the rate of rRNA synthesis and the previously determined rate of degradation is consistent with the observed constancy of the rRNA pool size during pharate adult development.

The contribution of the fatbody to RNA and ribosomal changes during development of the blowfly Calliphora erythrocephala (Meig.)

Abstract The initiation of blowfly metamorphosis is associated with a pronounced decrease in the number of larval ribosomes; this reduced number then remains constant throughout pharate adult development. Ribosomal RNA accounts for most of the total RNA in larvae shortly after the cessation of feeding and growth, but thereafter the amount of rRNA declines disproportionately to total RNA until early pharate adult development; thereafter, the ratio remains constant until adult emergence. Larval fatbody ribosomes, which constitute about half of the total in the entire organism, are destroyed in situ prior to pupariation. The progressive decrease in fatbody rRNA is accompanied by a corresponding increase in a degraded, relatively insoluble 4–7 S nucleic acid which, stored until adult emergence when it is discarded, accounts for the disparity between total RNA and rRNA. The extracellular ribosomes previously observed during pharate adult development are thus derived from dissolution of larval tissues other than fatbody.

A study of the quantitative significance of protein synthesis during the metamorphosis of the sheep blowfly Lucilia

Lysine pool size and its turnover have been estimated during the metamorphosis of the blowfly L. cuprina; the turnover of [ 14C]lysine was shown to be rapid. Using this information and rates of incorporation of labelled [ 14C]lysine into protein, the rates of synthesis of protein have been calculated for the period in the puparium and for early postemergence adult development. Protein synthesis in vivo was inhibited almost completely by the inhibitor cycloheximide. High rates of synthesis of protein by the head, thorax, and abdomen are maintained during the period shortly before and after adult emergence, and it was shown that synthesis of protein is the major sink for lysine from the free amino-acid pool at most stages of development in the puparium. An attempt has been made to correlate the observed rates of synthesis with morphological information. Using these and published results, theories of protein interconversion in Dipteran metamorphosis have been re-evaluated. It appears that the formation of the proteins of the adult insect occurs by de novo protein synthesis during metamorphosis.

The influence of juvenile hormone on the metamorphosis of Sarcophaga bullata

The following substances with juvenile hormone activity were assayed on Sarcophaga bullata: pure Hyalophora cecropia juvenile hormone; dl-juvenile hormone; C 17 methyl ester; epoxy C 17 ethyl ester; a synthetic mixture; epoxy methyl farnesoate; piperonyl butoxide; sesoxane. Larvae respond to injections of juvenile hormone by a prolongation of larval life and in many instances by developmental arrest during pharate adult development. All substances are effective in eliciting the development of pupal-adult intermediates when applied to the cuticle of young pupae. These intermediates have secreted second pupal cuticles. Another effect on young pupae is developmental arrest during early pharate adult development. Our data are the first to demonstrate a morphogenetic effect of juvenile hormone on the higher Diptera.

Critical periods of maze acquisition development in euthyroid and hypothyroid rodents.

Mice and rats with congenitally-induced hypothyroidism which continued through early adult development were compared with euthyroid animals for acquisition of a simple sensori-motor maze escape response at various periods during development. Whereas euthyroid mice began to demonstrate criterion maze acquisition as early as 16 days of age, and all showed acquisition to criterion by 20 days of age, only a small percentage of hypothyroid mice acquired the maze response between 25 and 30 days of age. Hypothyroid rats, as well as their euthyroid controls, did not show maze acquisition to criterion by 18 days of age; and, whereas the latter had shown the ability to acquire the maze at 50 days of age, hypothyroid animals still showed a decided deficit in maze acquisition at this time.