Review of early developmental stages of trilobites and agnostids from the Barrandian area (Czech Republic)

2017 ◽  
Vol 186 (1) ◽  
pp. 103-112
Author(s):  
Lukáš Laibl ◽  
Oldřich Fatka

This contribution briefly summarizes the history of research, modes of preservation and stratigraphic distribution of 51 trilobite and five agnostid taxa from the Barrandian area, for which the early developmental stages have been described.

2021 ◽  
Vol 22 (3) ◽  
pp. 1210
Author(s):  
Krzysztof Formicki ◽  
Agata Korzelecka-Orkisz ◽  
Adam Tański

The number of sources of anthropogenic magnetic and electromagnetic fields generated by various underwater facilities, industrial equipment, and transferring devices in aquatic environment is increasing. These have an effect on an array of fish life processes, but especially the early developmental stages. The magnitude of these effects depends on field strength and time of exposure and is species-specific. We review studies on the effect of magnetic fields on the course of embryogenesis, with special reference to survival, the size of the embryos, embryonic motor function, changes in pigment cells, respiration hatching, and directional reactions. We also describe the effect of magnetic fields on sperm motility and egg activation. Magnetic fields can exert positive effects, as in the case of the considerable extension of sperm capability of activation, or have a negative influence in the form of a disturbance in heart rate or developmental instability in inner ear organs.


Genes ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 638
Author(s):  
Monika Mazur ◽  
Daria Wojciechowska ◽  
Ewa Sitkiewicz ◽  
Agata Malinowska ◽  
Bianka Świderska ◽  
...  

The slime mold Dictyostelium discoideum’s life cycle includes different unicellular and multicellular stages that provide a convenient model for research concerning intracellular and intercellular mechanisms influencing mitochondria’s structure and function. We aim to determine the differences between the mitochondria isolated from the slime mold regarding its early developmental stages induced by starvation, namely the unicellular (U), aggregation (A) and streams (S) stages, at the bioenergetic and proteome levels. We measured the oxygen consumption of intact cells using the Clarke electrode and observed a distinct decrease in mitochondrial coupling capacity for stage S cells and a decrease in mitochondrial coupling efficiency for stage A and S cells. We also found changes in spare respiratory capacity. We performed a wide comparative proteomic study. During the transition from the unicellular stage to the multicellular stage, important proteomic differences occurred in stages A and S relating to the proteins of the main mitochondrial functional groups, showing characteristic tendencies that could be associated with their ongoing adaptation to starvation following cell reprogramming during the switch to gluconeogenesis. We suggest that the main mitochondrial processes are downregulated during the early developmental stages, although this needs to be verified by extending analogous studies to the next slime mold life cycle stages.


Biotemas ◽  
2018 ◽  
Vol 31 (3) ◽  
pp. 15-23
Author(s):  
Kamilla Pacheco Govêa ◽  
Antônio Rodrigues Cunha Neto ◽  
Natália Martins Resck ◽  
Letícia Leite Moreira ◽  
Valdir Veroneze Júnior ◽  
...  

O alagamento no solo é um fenômeno que reduz a sobrevivência, o crescimento e o desenvolvimento de plantas, podendo ocasionar queda na produtividade quando essas são agricultáveis. O maracujazeiro (Passiflora edulis Sims) é uma frutífera comercial com propriedades medicinais cuja produção incentiva a irrigação; e não são encontrados estudos que apresentem efeitos do excesso de água no solo sobre estas plantas. O objetivo deste trabalho foi verificar alterações morfoanatômicas e fisiológicas no desenvolvimento inicial de plântulas de maracujazeiro expostas a diferentes níveis de água no solo. As plântulas foram organizadas em três tratamentos: solo com capacidade de campo, pré-submergido e alagado. Após sete dias, foram feitas análises de trocas gasosas, potencial hídrico, quantificação de prolina e cortes anatômicos de raízes. O solo alagado influencia as trocas gasosas e afeta negativamente a fotossíntese. Não houve alterações no potencial hídrico nem na quantificação de prolina entre os tratamentos. Os tratamentos pré-submergido e alagado apresentaram aerênquima e aumento no diâmetro das raízes e na espessura das barreiras apoplásticas e do córtex. O maracujazeiro apresentou alterações fisiológicas e anatômicas que permitiram sua sobrevivência em condições pré-submergidas e alagadas, o que significa que plântulas jovens dessa espécie suportam maiores quantidades de água no solo.


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