Single Sigmoid Pattern Research Articles

Investigating the Growth of Bacteria using Double Sigmoid Model with Reparameterization

The growth of an organism can be modeled using a growth curve. However, bacteria's growth pattern differs from other organisms. Bacterial growth is divided into four phases: lag, logarithmic, stationary, and death. The experts re-parameterized the growth curve to match the growth phase of the bacteria. Bacterial growth patterns generally do not show a single sigmoid pattern but form two curves. Therefore, the double sigmoid model is more suitable. This study modeled the growth of the Pseudomonas putida bacteria by observing the optical density of the medium. Model parameters are estimated using the Non-Linear Least Square (NLS) method with the Gauss-Newton algorithm. The modeling results show that the double sigmoid model fits the growth curve of Pseudomonas putida better than the single sigmoid model. The Double Logistic model outperforms all models with the highest adjusted R2 and the smallest RMSE, AIC, and BIC values.

Transcriptome analysis reveals gene associated with fruit size during fruit development in pear

Fruit size, one of the crucial traits of fruit, affects pear fruit quality. Usually, both velocity and duration of swelling determines fruit size. However, fruit enlargement studies involving gene regulation during pear fruit development are very limited. In this study, fruit weight, transverse and longitudinal diameters, fruit core, and flesh volume were measured. Cell sizes were presented by paraffin sections, and the number of cells was counted from fruitlet to mature fruit of the CG, XQ, and HS cultivars. Results revealed that pear fruit enlargement was a single sigmoid pattern and was determined by cell number and cell size during fruit development. In addition, transcriptome sequencing was conducted for the fruitlet, early enlargement, late enlargement, and ripening stages. By analyzing the Venn diagram, 156 and 186 differentially expressed genes (DEGs) were selected and identified for the early and late enlargement of pear fruit, respectively. Of these genes, we performed to analysis of gene function annotation and chromosome location. Furthermore, 14 DEGs were located in the reported quantitative trait locus (QTL) regions associated with pear fruit size. Taken together, the results of this study provide information on fruit size from transcriptome analysis and the potential molecular mechanism of candidate genes regulating fruit size in pear.

Comparative transcriptome analyses of fruit development among pears, peaches, and strawberries provide new insights into single sigmoid patterns

BackgroundPear fruit exhibit a single sigmoid pattern during development, while peach and strawberry fruits exhibit a double sigmoid pattern. However, little is known about the differences between these two patterns.ResultsIn this study, fruit weights were measured and paraffin sections were made from fruitlet to maturated pear, peach, and strawberry samples. Results revealed that both single and double sigmoid patterns resulted from cell expansion, but not cell division. Comparative transcriptome analyses were conducted among pear, peach, and strawberry fruits at five fruit enlargement stages. Comparing the genes involved in these intervals among peaches and strawberries, 836 genes were found to be associated with all three fruit enlargement stages in pears (Model I). Of these genes, 25 were located within the quantitative trait locus (QTL) regions related to fruit weight and 90 were involved in cell development. Moreover, 649 genes were associated with the middle enlargement stage, but not early or late enlargement in pears (Model II). Additionally, 22 genes were located within the QTL regions related to fruit weight and 63 were involved in cell development. Lastly, dual-luciferase assays revealed that the screened bHLH transcription factors induced the expression of cell expansion-related genes, suggesting that the two models explain the single sigmoid pattern.ConclusionsSingle sigmoid patterns are coordinately mediated by Models I and II, thus, a potential gene regulation network for the single sigmoid pattern was proposed. These results enhance our understanding of the molecular regulation of fruit size in Rosaceae.

Morphological, biochemical and qualitative changes associated with growth and development of pomegranate fruit (Punica granatum L.)

Morphological, biochemical and qualitative changes occurred during growth and development of three pomegranate cultivars were studied at AICRP on Arid Zone Fruits, Department of Horticulture, MPKV, Rahuri. Various changes were determined at 30 days intervals from anthesis till harvest. The pomegranate fruit in all cultivars showed single sigmoid pattern of growth. The size, weight and volume of the fruit of each cultivar increased while the specific gravity increased earlier and then decreased after 90 days in Cv. Bhagwa and after 120 days in Cv. Mridula and Sel-4 to less than one. The elongated oval shape of fruit at the early stage changed to round with prominent suppressions on sides at maturity stage. From those studies, it was revealed that the pomegranate fruits showed colour changes from initial green to orange red and high red at maturity stage and it can be harvested within 150 to 180 days. Among biochemical changes the total soluble solids and TSS: acid ratio increased while the acidity decreased with the advancement in the age of fruit. The total anthocyanin content in arils of pomegranate fruit increased with the advancement in the age of fruit. For qualitative changes, it was found that the percentage of arils and the juice content of arils increased, while the percentage of rind, rind thickness and seed content decreased gradually with the advancement in the age of fruit in each cultivar under study. The percentage of juice content was higher in Mridula at all the stages of maturity than Bhagwa and Sel-4. Seed hardness increased as the fruit matured. Incidence of internal breakdown of arils was noticed earlier in Bhagwa.

Russeting and Relative Growth Rate Are Positively Related in ‘Conference’ and ‘Condo’ Pear

Russeting is an important surface disorder in fruit and mechanical growth stresses, among other factors, are considered causal in russet induction. To test this hypothesis, fruit development and russeting were monitored on a whole fruit level and also in the calyx, cheek, and neck region of developing ‘Conference’ and ‘Condo’ pear fruit (Pyrus communis L.). To quantify growth, the pear fruit was geometrically modeled as approximating to half of a prolate spheroid for the calyx region and two truncated cones for the cheek and neck regions, respectively. Mass and surface area of ‘Conference’ and ‘Condo’ fruit increased in a single sigmoidal pattern with time. Fruit volume, determined by buoyancy, using a hydrostatic balance, and the Archimedes’ principle was closely related to that predicted by the model from fruit geometry. Growth rates of surface area in ‘Conference’ and ‘Condo’ peaked at ≈90 and 100 days after full bloom (DAFB), respectively, and were highest in the calyx followed by the cheek and neck regions. Relative growth rates, calculated by dividing growth rates by the absolute surface area present at that time, were at maximum during early development and thereafter continuously declined. In general, relative growth rates were highest for the cheek region, intermediate in the calyx, and lowest for the neck. ‘Conference’ fruit were always more russeted than ‘Condo’ with russeting generally decreasing from calyx to cheek and neck. Furthermore, russeting increased rapidly in ‘Conference’ during early development until ≈70 DAFB, particularly in the calyx and cheek regions and, to a lesser extent, in the neck region. There was little change in russeting after ≈70 DAFB. Plotting rates of russeting vs. relative growth rates in surface area indicate a positive and common relationship across regions where russeting increased when relative growth rates exceeded 0.03/day. Thus, differential growth rates between regions within ‘Conference’ or ‘Condo’, but not across the two cultivars, accounted for topical differences in russeting.

Evaluation of quality indices during fruit development and ripening in 'Wonhwang' and 'Whasan' pears

In this study, we evaluated the changes of fruit quality indices during fruit development and ripening in Korean new pear cultivar 'Wonhwang' and 'Whasan' to determine appropriate harvest time and to enhance the marketability. The fruit of each cultivar harvested from 100 days after full bloom (DAFB) to 135 and 150 DAFB in 'Wonhwang' and 'Whasan', respectively. The fruit growth of both cultivars showed a typical single sigmoidal pattern. Flesh firmness of two cultivars decreased continuously with fruit development and ripening, reaching a final level of about 2.6 kgF at harvest stage. The starch content of fruit sap was much higher in the fruits of early development stage than the later stage of fruit ripening. In 'Wonhwang' pears, the starch level decreased coincide with fruit ripening (130 DAFB), while that of 'Whasan' decreased from very early stage of fruit development (120 DAFB), 30 days before full ripe. 'Whasan' pear showed much lower acidity level of about 0.13% during fruit development and ripening period compared with that of 'Wonhwang'. Therefore, the ratio of soluble solids to total acidity (TSS/acid) increased gradually with fruit development and ripening, reaching a final level of 80 and 98 in 'Wonhwang' and 'Whasan', respectively. There were no climateric rise of fruit respiration during fruit ripening periods in two oriental pear cultivar. The changes of skin color difference including hunter vale a* which means loss of green color occurred only after onset of ripening in two cultivars.

Desenvolvimento do fruto da lichieira (Litchi chinensis Sonn.) 'Bengal'

Estudou-se o desenvolvimento do fruto da lichieira (Litchi chinensis Sonn.) 'Bengal'. Realizaram-se amostragens semanais, com início aos 35 dias após a antese e término no início da senescência dos frutos. A partir do 77º dia após a antese, os frutos foram decompostos em pericarpo, semente e arilo. A antese ocorreu na primeira semana de setembro. Foram ajustados modelos sigmoidais simples para acúmulo de matéria seca, comprimento e diâmetro. Para o acúmulo de matéria seca, uma fase inicial, de crescimento lento, prolongou-se até o 63º dia após a antese e coincidiu com um período de intensa queda natural de frutos. Do 63º ao 98º dia após a antese, houve uma fase de rápido acúmulo de matéria seca. Até o 77º dia, pericarpo e semente foram os principais responsáveis pelo acúmulo de matéria seca. Oitenta e oito por cento do comprimento e 65% do diâmetro máximos foram atingidos nesse período. Do 84º ao 98º dia após a antese, o desenvolvimento do fruto foi determinado basicamente pelo arilo. As dimensões e a matéria seca do fruto estabilizaram-se a partir do 98º dia após a antese. O ponto de colheita comercial dos frutos, caracterizado pela coloração avermelhada do pericarpo, ocorreu a partir do 112º dia após a antese. Verificou-se um quadro senescente nos frutos a partir do 119º dia após a antese.

Cell Structure and Sugar and Acid Contents in the Arils of Developing Pomegranate Fruit

The growth curves of the developing pomegranate (Punica granatum L.) fruit (diam.) and seed (FW) display a single sigmoid pattern. The number of seeds in fruit varied from 100- 500, and the relationship between fruit diameter and seed number correlated significantly. The outer layer of testa or aril was reconfirmed to consist of a single, huge, elongated cell that extended to more than 2.3 mm. Glucose and fructose were the main sugars in the juice of the edible portion. The titratable acid content decreased from 9.5% to 4.0% as the fruit matured and accumulated sugars.

Growth and Developmental Responses of Seeded and Seedless Grape Berries to Shoot Girdling

The relationship of assimilate supply to grape (Vitis vinifera L.) berry growth and development was studied with a seeded (`Kyoho') and a seedless (`Seedless Wuhehong') cultivar. A single shoot girdling between the second and third nodes below the basal cluster at the end of Stage I of berry growth shortened Stage II (the lag phase) of `Kyoho' grape berries by 10 days, and eliminated Stage II in `Seedless Wuhehong' grape berries. Double shoot girdling between the second and third nodes below the basal cluster and above the upper cluster, respectively, at the same time at the end of Stage I, advanced Stage II by 3 days in both cultivars. Normal accumulation of dry weight in the `Kyoho' grape berry is in a double sigmoidal pattern, but it became a single sigmoidal pattern in response to a single basal girdling. The highest percent moisture in berries was at 20 days after full bloom. Rapid changes in berry pectin substances lagged behind those of soluble solids and titratable acidity, and behind the onset of berry softening at veraison in `Kyoho', but not in `Seedless Wuhehong', for which the three processes were concurrent. It is suggested that the slow growth of the berries during Stage II is a result of a decrease in the rate of water accumulation on a whole berry basis and a decrease in accumulation of dry matter in the skin and flesh (pericarp) due to assimilate competition within grapevines and within berries. The relationships between levels of endogenous hormones (IAA, GA3, zeatin, zeatin riboside, and ABA) and berry growth were also studied with `Kyoho' grapes. The results showed that the slow growth of grape berries during Stage II was associated with assimilate competition between the skin-flesh (pericarp) and seeds, and with peak shifts of concentrations of IAA, GA3, zeatin and zeatin riboside. Changes in ABA levels were closely associated with ripening and senescence during late Stage III.

Fruit growth and abscission in Macadamia imtegrifolia

Growth in diameter of fruits (follicles) of five cultivate of Macadamia integrifolia Maiden and Betche followed a single sigmoidal pattern. A rapid increase in fruit diameter began 2 to 3 weeks after anithesis and continued until weeks 14 to 16. No further increase in size was observed after 16 weeks. Growth in fresh weight of the two cnltivars observed also followed a single sigmoidal pattern. A rapid increase in fresh weight began 5 to 6 weeks after anthesis and continued until weeks 15 to 18. No further increase in fresh weight was evident after 18 weeks. Abscission of flowers and fruits occurred continuously from anthesis through fruit maturity and could be separated into three periods. The first period of abscission occurred in the first 2 weeks after anthesis and commonly involved over 90% of the flowers. The second period of abscission occurred from 3 to 8 weeks after anthesis and commonly involved over 80% of the initial set of small fruit. This period of abscission occurred prior to and concurrent with the rapid increase in growth. The third period of abscission was gradual and occurred from 9 weeks after anthesis until maturity at 28 to 30 weeks. Measurement of ethylene evolution by fruits showed a peak during weeks 3 and 4. This was prior to the peak in relative abscission rate at week 5. The fruit removal force increased from anthesis through week 12 and decreased from week 24 through maturity.

Pomegranate fruit development and maturation

SummaryThe development of pomegranate fruit was studied under continental (Bet Shean Valley) and moderate maritime (coastal plain) climatic conditions. Fertile flowers were vase-shaped and developed into fruits. Bell-shaped flowers with few egg cells were sterile and did not produce fruits. Gibberellic acid induced the sterile flowers to develop into small fruits; however, these were devoid of juicy seeds. The growth curve of pomegranate fruits from both climatic regions showed a single sigmoid pattern. The seeds accounted for about half of the fruit weight. The edible juicy tissue of the seeds grew continuously from June to October whereas the internal stone tissue stopped growing and hardened by the end of June. Juice, total soluble solids (TSS) and anthocyanin content increased continuously during maturation while acidity decreased. Fruit of cv Mule’s Head ripens early and has a low acid content, whereas fruit of the late-ripening cv Wonderful has high juice contents, TSS, acids and anthocyanins, and i...

The tamarillo: Fruit growth and maturation, ripening, respiration, and the role of ethylene

AbstractThe tamarillo (tree tomato, Cyphomandra betacea Sendt.) flowers and sets fruit over an extended period. Many blossoms and young fruits abscise; survival of tagged fruitlets ranged from 0 to 32%. Tagged fruits were harvested at known ages for measurement of size and shape, respiration rate, ethylene production, and response to ethylene treatment. Fruit growth followed a single sigmoid pattern, and fruits were commercially mature at 21–24 weeks after anthesis. The amount of red skin pigment increased with age from 15 weeks, but harvesting of immature fruits appeared to stop red pigment development. Fruits harvested at 12–19 weeks or younger shrivelled in storage. Respiration studies showed tamarillo fruits to be non‐climacteric, and only traces of ethylene were produced until final senescence. Ethylene treatment increased the respiration rate and hastened senescence of harvested fruits of all ages. The yellow strain behaved similarly to the red and had a somewhat longer storage life.