جستجوی مقالات مرتبط با کلیدواژه « Pulp » در نشریات گروه « زیست شناسی »

Among the sources of oils (vegetable, animal, microorganism), microbial oil has attracted the attention of many researchers. Oily microorganisms are able to accumulate 20 to 80% of lipids in each dry biomass. Among various microorganisms (bacterias, microalgae, fungal species including yeasts), some yeasts are considered to be the superior source of oil production. Yarrowia lipolytica</em> is an excellent example of oily microorganisms with high fat production efficiency. By using cheap, native and available pulp as a production medium, the cost of oil produced by yeasts can be reduced. The microbial oil produced is used for medicinal, food and cosmetic purposes. In this study, the pleomorphism of Yarrowia lipolytica</em> (ATCC 18942) was examined microscopically in different culture media. After culturing the  yeast in media containing olive, sesame and sunflower pulp, in semi-open culture conditions, the fatty acids produced were analyzed using GC-MS and FTIR techniques. After reviewing the results, the medium containing olive pulp was selected and the microbial lipid produced in this medium was extracted. Then dry weight of biomass and microbial fat were measured. The results showed that the fatty acids extracted from the medium containing olive oli cake included oleic acid, palmitic acid, linoleic acid and stearic acid, which had the best production of fatty acids among the pulp. The content of  microbial fat and dry weight were 4.07 and 7.83 g/l, respectively, and microbial fat production efficiency was 51.97%. 

Since Aloe vera has special adaptations to the environmental conditions of Iran, it has industrially utilized. The more studying physiological and biochemical properties of usable tissues improves its utilizing. In this study the effects of iron nutrition on the iron concentrations in different leaf tissues and the activity of superoxide dismutase were investigated. Propagated plants from a maternal scion were treated by different concentrations of iron (0, 5, 10 and 20 µM) in two chelate forms, FeEDTA and FeEDDHA in a fully factorial complete design. The results showed no difference between the two iron chelate forms in iron concentrations in tissues. The most increasing in iron concentration was observed in leaf surface tissues by using higher concentrations of iron in medium. Total superoxide dismutase activity in different tissues was not influenced by iron concentration in medium. Study of different SOD isozymes showed a constitutive activity of MnSOD in all of tissues. The activity of FeSOD was more apparent in surface tissues but it was induced in pulp in higher concentrations of iron. In all of the used iron concentrations, the activity of Cu/ZnSOD observed in surface tissues but it was never observed in pulp. It could be suggested that pulp as the most important industrial usable tissue is not a source for accumulation of iron. The activity of SOD could be induced in pulp by increasing in iron concentration. Indeed an induction in the activity of Cu/ZnSOD in pulp could be investigated by increasing in Cu and/or Zn concentrations.

Today, with the arrival of enzymes as biological catalysts in pulp and paper industry, we are witnessing the development of the industry, improve the quality of paper production, saving cellulose resources and increase crop yields. This article will explain the role of the most important industrial enzymes used cellulase, hemi-cellulase, endoglucanase, Lakaz, lipase and esterase present in the pulp and paper industry.  The results showed that the enzyme has advantages such as reducing the need for chemicals, improve the quality of bleached, increased strength and resistance properties of paper, deinking and pulp are removed from the viscous polymeric materials. So improve the quality of the papers are produced without environmental damage. Since the enzyme is more effective than the traditional paper industry, the need for more research on industrial enzymes and their applications in the pulp and paper manufacturing process to further progress seems necessary in pulp and paper industry.

Formations of feather and hair follicles during embryonic stage are nearly similar. The aim of the present research is to study the similarities and differences between these two follicles in adult pigeons and rats. To fulfill this task, feather and hair follicles were dissected and processed for light and electron microscopy. The results demonstrated that these two follicles were similar in having dermal papilla and epidermal matrix. Moreover, the production of feather fibers and hair in them, respectively, is almost similar. However, unlike the hair follicle, the feather follicle has a distinct compartment, called the pulp at the top of the papilla. At the center of this pulp and dermal papilla a blood vessel exists, a character never observed in the hair follicle. Another difference between the two related to the thickness of the basement membrane exists at the interface between the papilla and epidermal matrix which in feather follicle is much thicker than its hair equivalent. In addition, at the base of feather follicle there is a distinct population of stem-like cells which could not be distinguished in the hair follicle. Based on the results obtained in this study, it seems that the feathers in birds and the hairs in mammals have been adapted for different biological tasks.