Trends in Oil Production from Oleaginous Yeast Using Biomass: Biotechnological Potential and Constraints

In the present scenario of depleting oil reservoir, microbial oil has gained much attention over plant and animal based sources. Among different microorganisms, yeast strains are considered superior source for oil production. The cost of oil produced by yeast could further be lowered using cheaper agro-waste and biomass as substrate. This review focuses on key topics which will help in gaining better understanding to enhance lipid production using yeast strains. The effects of oleaginous yeast co-culturing with microalgae, different cheap carbon sources of biomass, and types of yeast species on oil production were highlighted in the review. An overview of mechanisms of oil production from biomass, viz. pretreatment of biomass, fermentation and oil recovery are also provided. Constraints encountered during the oleogenesis or microbial oil accumulation and their probable solutions along with a section on different by-products obtained during oleo-genesis are also discussed.     

Photoinhibition of photosynthesis: effect of O2 and selective excitation of the photosystems in intact Lemna gibba plants

Intact Lemna gibba plants were photoinhibited under anaerobic conditions on illumination with monochromatic light which selectively excited the photosystems. Photoinhibition was less when PS 1 was excited and greatest when mainly PS 2 was excited, which suggests that PS 2 was most damaged by photoinhibition induced in complete absence of O₂ and CO₂.The illumination of plants with monochromatic light exciting PS 1, at different O₂ concentrations (in CO₂ deficient conditions), showed that PS 1 photoinhibition was increased at the low O₂ concentrations. The damage to PS 1 was more evident at 2% O₂ than at the higher O₂ concentrations.CO₂ as well as O₂ at atmospheric concentration, (air), was necessary for complete protection of the plant from photoinhibition when both photosystems were excited either separately or together.Abbreviations I irradiance, photon fluence rate - PCO photosynthetic carbon oxidation cycle - PCR photosynthetic carbon reduction cycle - PS 1 photosystem 1 - PS 2 photosystem 2     

Chlorolepiota indica sp. nov.—A new species from India

A new species Chlorolepiota indica is reported from Patiala in Punjab, India. The fungus is characterized by convex brown pileus covered by concentrically arranged brown scales with yellow tinge around the umbo. The stipe of the fruiting body is cream to pale yellow, pinkish to reddish brown near the pileus, and yellowish to dark grey brown towards the base.     

Reproductive phase dependent circadian variation in hypothalamic concentration of serotonin, dopamine and peripheral thyroxine levels in Japanese Quail following 5-HTP and L-DOPA administration at specific time intervals

Temporal phase relations of circadian hypothalamic neurotransmitters are reported to regulate seasonal reproduction in some avian species. Present experiments were designed to study circadian variation in the hypothalamic concentration of neurotransmitters (serotonin and dopamine) and the plasma thyroxine level in sexually active (long day) and inactive (short day) Japanese Quail. A significant circadian cycle was noted in the hypothalamic content of both serotonin and dopamine, but with different patterns. In breeding Quail, peak activity of serotonin and dopamine was noted at 10.00 A.M. and 10.00 P.M. respectively i.e. at the interval of 12 hours. However, during sexually quiescent condition, peaks of both neurotransmitters occurred at 2.00 P.M. i.e. having a 0-hour temporal relationship. During the breeding phase, the plasma thyroxine level showed a biphasic pattern with two circadian peaks at 10.00 A.M. and 10.00 P.M. whereas in the non-breeding condition a single peak was observed at 10.00 A.M. In the second experiment, to study the effect of temporal synergism of neurotransmitter precursor drugs on circadian cycles, two groups of Quail were administered daily with serotonin precursor 5-HTP (5-hydroxytryptophan) and dopamine precursor L-DOPA (L-dihydroxyphenylalanine) (5 mg/100 g body weight) 12 hour (12-hr) and 8 hour (8-hr) apart over a period of 11 days under continuous conditions of light and then transferred to long day length for 15 days when the experiment was terminated. When compared to controls, the 12-hr condition induced breeding while the 8-hr condition led to a non-breeding condition. The circadian pattern of serotonin levels of control and 12-hr Quail was similar to that of a normal sexually active bird, while that of the 8-hr Quail showed the pattern of a sexually inactive bird. The plasma thyroxine level exhibited a biphasic pattern in 12-hr Quail, which was similar to a normally breeding bird, whereas unlike sexually inactive birds, the thyroxine concentration in 8-hr Quail was relatively low and did not show significant cyclicity. Interestingly, the plasma testosterone level of 12-hr Quail followed a more or less similar pattern with peak activities coinciding with that of thyroxine i.e. biphasic in the sexually active condition (12-hr and control) but a single peak in the quiescent (8-hr) condition. These findings suggest that the temporal phase relation of circadian serotonergic and dopaminergic oscillator varies as a function of reproductive status of the bird, and breeding/non-breeding conditions may be induced experimentally by changing the phase relation of these oscillations.     

Pollen morphology of Sorghum Moench – Sections Eu-sorghum and Para-sorghum

Pollen morphological studies have been carried out by SEM on 23 species of Sorghum (Gramineae) in order to resolve the exine surface patterns in sections Eu-sorghum (subsection Arundinacea-series Spontanea and Sativa and subsection Halepensia), and Para-sorghum. Basically, two exine ornamentation types have been observed viz. granular and insular. In section Eu-sorghum, series Spontanea and Sativa (of subsection Arundinacea) are heterogeneous having both types of exine pattern. In the same section, subsection Halepensia is characterised by having only a granular exine. Section Para-sorghum shows a marked pollen morphological similarity with subsection Halepensia of section Eu-sorghum. Snowden's concept that the two series Spontanea and Sativa are closely related and that the cultivated Sorghum (series Sativa) might have evolved from the wild Sorghum (series Spontanea), is supported by the present observations.     

Computational identification of miRNAs,their targets and functions in three‐spined stickleback (Gasterosteus aculeatus)

An intriguing question in biology is how the evolution of gene regulation is shaped by natural selection in natural populations. Among the many known regulatory mechanisms, regulation of gene expression by microRNAs (miRNAs) is of critical importance. However, our understanding of their evolution in natural populations is limited. Studying the role of miRNAs in three‐spined stickleback, an important natural model for speciation research, may provide new insights into adaptive polymorphisms. However, lack of annotation of miRNA genes in its genome is a bottleneck. To fill this research gap, we used the genome of three‐spined stickleback to predict miRNAs and their targets. We predicted 1486 mature miRNAs using the homology‐based miRNA prediction approach. We then performed functional annotation and enrichment analysis of these targets, which identified over‐represented motifs. Further, a database resource (GAmiRdb) has been developed for dynamically searching miRNAs and their targets exclusively in three‐spined stickleback. Finally, the database was used in two case studies focusing on freshwater adaptation in natural populations. In the first study, we found 44 genomic regions overlapping with predicted miRNA targets. In the second study, we identified two SNPs altering the MRE seed site of sperm‐specific glyceraldehyde‐3‐phosphate gene. These findings highlight the importance of the GAmiRdb knowledge base in understanding adaptive evolution.