histomorphologic and histomorphometric studies on the pancreas of mehraban male sheep were done in four age groups: fetus, neonate, young adult and old age in this respect, we used special stainings, light microscope and ocular micrometer. the results showed that the smooth muscles were absent in capsule. the tubular portion of exocrine pancreas was more prominent. neuroinsular complex and beta...

The diversity and function of small RNAs continue to both amaze and puzzle biologists. This Molecular Biology Select highlights recent advances in our efforts to understand the biological functions of two kinds of small RNAs, microRNAs (miRNAs) and piwi-associated RNAs (piRNAs). Two new studies identify miRNAs in the unicellular green alga Chlamydomonas reinhardtii, posing new questions about t...

Paramecium is a unicellular organism that swims in fresh water by beating thousands of cilia. When it stimulated (mechanically, chemically, optically, thermally…), often backward then turns and forward again. This avoiding reaction triggered calcium-based action potential. For this reason, some authors have called swimming neuron. review summarizes current knowledge about the physiological basi...

Pentameric ligand-gated ion channels (pLGICs) are ubiquitous neurotransmitter receptors in Bilateria, with a small number of known prokaryotic homologues. Here we describe a new inventory and phylogenetic analysis of pLGIC genes across all kingdoms of life. Our main finding is a set of pLGIC genes in unicellular eukaryotes, some of which are metazoan-like Cys-loop receptors, and others devoid o...

The taxon Protista was originally given by Ernst Haeckel in 1866 and included all unicellular organisms either prokaryotic or eukaryotic. In the modern view, the protists are eukaryotic organisms of unicellular organization, and thus the term embraces classical protozoa, unicellular phototrophic organisms such as diatoms, and lower unicellular fungi (28). Due to the extreme diversity, the taxon...

Abstract We have recently proposed a novel strategy named photosynthetic tissue engineering to overcome clinical problems due hypoxia. The idea is based on transgenic photoautotrophic microorganisms that produce oxygen and at the same time secrete functional recombinant proteins into tissues. In particular, unicellular green alga Chlamydomonas reinhardtii has successfully been used boost regene...

Animals, plants and fungi undergo an aging process with remarkable physiological and molecular similarities, suggesting that aging has long been a fact of life for eukaryotes and one to which our unicellular ancestors were subject. Key biochemical pathways that impact longevity evolved prior to multicellularity, and the interactions between these pathways and the aging process therefore emerged...

In order to accommodate the physiologically incompatible processes of photosynthesis and nitrogen fixation within the same cell, unicellular nitrogen-fixing cyanobacteria have to maintain a dynamic metabolic profile in the light as well as the dark phase of a diel cycle. The transition from the photosynthetic to the nitrogen-fixing phase is marked by the onset of various biochemical and regulat...

Apoptosis is the most common phenotype observed when cells die through programmed cell death. The morphologic and biochemical changes that characterize apoptotic cells depend on the activation of a diverse set of genes. Apoptosis is essential for multicellular organisms since their development and homeostasis are dependent on extensive cell renewal. In fact, there is strong evidence for the cor...