Showing 3 results for Larval Development
Hamed Kolangi Miandare, Omid Jaafari, Maryam Nasrolah Pourmoghadam,
Volume 2, Issue 4 (3-2014)
Abstract
Oxygen concentration the environment and cellular organisms is one of the effective factors during normal development of organisms. In the present study, the transcription levels of the hypoxia-inducible factors (hif-1, hif-2) were evaluated during development of an ancient fish species Acipenser persicus, in the normal oxygen density of environment. The transcription of hif-1, hif-2 detected in all developmental time-points defined, from embryo to juvenile stages. Target genes transcriptions were normalized using RPL6 as reference gene. Changes in normalized hif-1, hif-2 mRNA expression were statistically significant throughout developmental points (p<0.05). Our data revealed that the mRNA expression of hifs were low during embryonic development and then upregulated significantly at hatching and early larval time-points. Then, in the late larval development and juvenile stage the expression of hifs started to decline. The comparison between hif-1 and hif-2 mRNA transcription showed that maximum gene expressions of hif-1and hif-2 occurred in 15 and 20 days after hatching, respectively. The increased expression of hifs suggests their association with two important events in the larval evolution, viz. internal feeding (yolk absorption) and external feeding. Also, the observed increase in mRNA expression of hifs during larval development of A. persicus can be attributed to increase in oxygen demand.
Ghadir Ghorbanzadeh, Gholamreza Rafiee, Soheil Eagderi, Hadi Poorbagher, Iraj Efatpanah,
Volume 3, Issue 2 (9-2014)
Abstract
The early morphological development and allometric growth pattern of Caspian kutum (Rutilus frisii kutum) during early development (from 0-35 days post hatch=dph) was studied. Morphological data were obtained using ImageJ software from 2D pictures and allometric growth patterns were computed based on Log10 y = Log10 α + βLog x function. Based on inflexion point of morphological traits and body shape changes, the early developmental of kutum were divided into Eleuthero-embryo, Propterygio-larval, Pterygio-larval” and younger juvenile phases, each of which included vital developmental events. Rapid and intense changes occurred during Eleuthero-embryo and Propterygio-larvae stages such as development of gills, depletion of yolk-sac and exogenous feeding, development of feeding apparatus, sense organs and organs related to swimming performance. The results also revealed that developmental changes occurred in agreement with the inflexion points of morphological characters and their developmental priority imply on functional importance of feeding, respiration and swimming related structures.
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Volume 9, Issue 2 (4-2020)
Abstract
The present study was conducted in Electric Blue Cichlid Sciaenochromis fryeri in early larval developmental stages from the fifth day post hatching (DPH) until 51 DPH to determine day of transforming from embryo to juvenile. Morphological characteristics were evaluated by using ImageJ software. Allometric growth patterns were calculated based on the formula Y=aXb. Yolk sac depletion was occurred on day 9. Scales were developed on day 19 and finaly developed juvenile shape. allometric pattern of different body segments were calculated according to isometry, positive, and negative allometry. Positive allometry of head and tail prior to inflexion point and variation in allometric growth pattern in different body segment determine priorities of organogenesis for survival in fish early life history. The obtained results showed consistency between the larval morphological changes and development of organs related to sensory movements and larval behavior. Every morphological change in larvae displays the development and evolution of one of the organs involved in feeding, breathing, swimming and sensory organs.
