Formative effects of morphactin on the shoot apical meristem of flax (linum usitatissimum L.).

The effect of a morphactin -- CF1 -- (2-chloro-9-hydroxyfluorene-9-carbocylic acid-methyl ester) on the morphogenesis of shoot apical meristem was studied on L. usitatissimum L. at three levels of supply. CF1 at 10 and 100 parts/10(6) induced repeated gamophylly resembling a concentric cupulate structure. GA3 superimposed at two levels viz. 10 and 100 parts/10(6) did not reverse this effect. The effect of CF1 is dose-dependent and reversal to normal behaviour occurs when the effect of CF1 wears off.     

Autophagy and senescence: A new insight in selected human diseases

Senescence and autophagy play important roles in homeostasis. Cellular senescence and autophagy commonly cause several degenerative processes, including oxidative stress, DNA damage, telomere shortening, and oncogenic stress; hence, both events are known to be interrelated. Autophagy is well known for its disruptive effect on human diseases, and it is currently proposed to have a direct effect on triggering senescence and quiescence. However, it is yet to be proven whether autophagy has a positive or negative impact on senescence. It is known that elevated levels of autophagy induce cell death, whereas inadequate autophagy can trigger cellular senescence. Both have important roles in human diseases such as aging, renal degeneration, neurodegenerative disorders, and cancer. Therefore, this review aims to highlight the relevance of senescence and autophagy in selected human ailments through a summary of recent findings on the connection and effects of autophagy and senescence in these diseases.     

Role of proline and glycinebetaine pretreatments in improving heat tolerance of sprouting sugarcane (<Emphasis Type="Italic">Saccharum</Emphasis> sp.) buds

High temperature strongly hampers the plant growth particularly at early growth stages. In this study, changes in some physiological and anatomical characteristics and possibility of mitigating the adversities of heat stress by soaking sugarcane nodal buds in 20 mM proline and glycinebetaine (GB) solutions have been explored. Heat stress reduced the rate of bud sprouting nonetheless soaking the setts in proline followed by GB was beneficial. In addition, heat stress reduced the bud fresh and dry weights, generated H₂O₂, reduced the tissue levels of K⁺ and Ca²⁺, while increased the osmolytes synthesis in a time course manner. Heat stress also delayed the emergence and expansion of new bud leaves, by restricting the number and area of mesophyll cells. It also caused poor and aberrant development and diffused appearance of mesophyll cells and vascular bundles in the bud leaves. However, soaking of buds in proline and GB solutions substantially reduced the H₂O₂ production, improved the accumulation of soluble sugars and protected the developing tissues from heat stress effects; although proline was more effective than GB. Correlations of various attributes indicated that soaking in GB and proline restricted the H₂O₂ generation, improved K⁺ and Ca²⁺ contents, and increased the concentrations of free proline, GB and soluble sugars eventually improving the heat tolerance of buds. Cost-benefit analysis showed that, considering increase in sprouting of buds, soaking in 20 mM solution of both osmoprotectants is economical.     

Some observations on the age and growth of thin-lipped grey mullet, Liza ramada Risso, 1826 (Pisces, Mugilidae) in three North African wetland lakes: Merja Zerga (Morocco), Garâat Ichkeul (Tunisia) and Edku Lake (Egypt)

Age and growth characteristics of the thin-lipped Grey Mullet (Liza ramada) were investigated in three North African wetland lakes: Merja Zerga (Morocco), Garâat Ichkeul (Tunisia) and Edku Lake (Egypt). Age structure of the mullet populations was very similar in all three study lakes. Small differences in growth were indicated, especially for the Moroccan population, where growth tended to be slower than for the other two populations. The fastest growth was observed in the Edku population while the best condition was observed in the Ichkeul population. Compared with some European populations, the sampled North African populations have faster growth and better condition factors.