Comparing photosynthetic and photovoltaic efficiencies and recognizing the potential for improvement

Comparing photosynthetic and photovoltaic efficiencies is not a simple issue. Although both processes harvest the energy in sunlight, they operate in distinctly different ways and produce different types of products: biomass or chemical fuels in the case of natural photosynthesis and nonstored electrical current in the case of photovoltaics. In order to find common ground for evaluating energy-conversion efficiency, we compare natural photosynthesis with present technologies for photovoltaic-driven electrolysis of water to produce hydrogen. Photovoltaic-driven electrolysis is the more efficient process when measured on an annual basis, yet short-term yields for photosynthetic conversion under optimal conditions come within a factor of 2 or 3 of the photovoltaic benchmark. We consider opportunities in which the frontiers of synthetic biology might be used to enhance natural photosynthesis for improved solar energy conversion efficiency.     

Site-specific nutrient requirements of NPK for potato (Solanum tuberosum L.) in Western Indo-gangetic plains of India based on QUEFTS

Abstract

Potato productivity in India is static due to unbalanced use of nutrients and intensive cropping system. Nutrient use efficiency and yield can be increased by application of nutrients based on quantitative approaches. We calibrated the quantitative evaluation of fertility of tropical soils (QUEFTS) model for the estimation of NPK requirements for different targeted yields of potato. Published data sets were used to calibrate the model. The results of the study showed that to produce one ton of potato tubers, 18, 4, and 24?kg N, P, and K, respectively, would be needed with internal efficiencies of 55, 285, and 42?kg tuber dry yield/kg N, P, and K removed. The observed yields of potato with different amount of nutrients were in agreement with the values predicted by the model. Therefore, the QUEFTS model based NPK fertilizer recommendations can be adopted for site-specific nutrient management of potato.     

Phylogeography,genetic stocks,and conservation implications for an Australian endemic marine turtle

1. Identification of the geographic extent of population boundaries, the distribution of genetic lineages, and the amount of genetic exchange among breeding groups is needed for effective conservation of vulnerable marine migratory species. This is particularly true of the flatback turtle (Natator depressus), which only breeds in Australia but has extensive migrations that can include international waters.
2. This study investigated the phylogeography and genetic structure among 17 flatback turtle rookeries across their range by sequencing an 810 bp portion of the mitochondrial DNA in 889 samples and genotyping 10 microsatellite loci in 598 samples.
3. There was low phylogenetic divergence among haplotypes and evidence of recent population expansion, likely in the late Pleistocene. A predominant haplotype was found across all rookeries, but other haplotype groups were regionally specific.
4. In general, there was agreement in patterns of genetic differentiation in the mitochondrial DNA and microsatellite data, and in some pairwise comparisons a higher mutation rate of microsatellites provided stronger evidence of differentiation.
5. These results suggest natal philopatry operates in the choice of breeding locations for males as well as females.
6. Evidence of genetic connectivity among neighbouring rookeries led to the identification of seven genetic stocks. Geographic boundaries of rookeries used by genetic stocks varied widely (160–1,300 km), highlighting a need for field studies to better understand movement patterns.
7. Hierarchical analysis of molecular variance identified significant genetic differentiation based upon genetic stock, nesting phenology (summer vs. winter nesters), and a west–east discontinuity across Torres Strait. A pattern of isolation by distance was identified, which was most strongly observed in the microsatellite data.
8. In combination with tagging and telemetry studies, these results will allow better quantification of stock‐specific threats along migratory routes and in foraging habitats. Implications of climate change will be stock specific and may depend upon the extent of genetic connectivity between neighbouring stocks.

     

Expression and Localization of Vascular Endothelial Growth Factor and its Receptors in the Corpus Luteum During Oestrous Cycle in Water Buffaloes (Bubalus bubalis)

The aim of this study was to document the expression and localization of VEGF system comprising of VEGF isoforms (VEGF 120, VEGF 164 and VEGF 188) and their receptors (VEGFR1 and VEGFR2) in buffalo corpus luteum (CL) obtained from different stages of the oestrous cycle. Real‐time RT‐PCR (qPCR), Western blot and immunohistochemistry were applied to investigate mRNA expression, protein expression and localization of examined factors. In general, all the components of VEGF system (the VEGF isoforms and their receptors) were found in the water buffalo CL during the oestrous cycle. The mRNA as well as protein expression of VEGF system was highest during the early and mid‐luteal phase, which later steadily decreased (p < 0.05) after day 10 to reach the lowest level in regressed CL. As demonstrated by immunohistochemistry, VEGF protein was localized predominantly in luteal cells; however, VEGFR1 and VEGFR2 were localized in luteal cells as well as in endothelial cells. In conclusion, the dynamics of expression and localization of VEGF system in buffalo corpora lutea during the luteal phase were demonstrated in this study, indicating the possible role of VEGF system in the regulation of luteal angiogenesis and proliferation of luteal as well as endothelial cells through their non‐angiogenic function.     

Effect of Antioxidants During Bovine In Vitro Fertilization Procedures on Spermatozoa and Embryo Development

Increased amounts of reactive oxygen species (ROS) during in vitro fertilization (IVF) may cause cytotoxic damage to gametes, whereas small amounts of ROS favour sperm capacitation. The aim of this study was to investigate the effect of antioxidants [50 μ m β-mercaptoethanol (β-ME) and 50 μ m cysteamine (Cyst)] or a pro-oxidant (5 m m buthionine sulfoximine) on the quality and penetrability of spermatozoa into bovine oocytes and on the subsequent embryo development and quality when added during IVF. Sperm quality, evaluated by the integrity of plasma and acrosomal membranes, and mitochondrial function, was diminished (p < 0.05) after 4-h culture in the presence of antioxidants. Oocyte penetration rates were similar between treatments (p > 0.05), but antioxidants adversely affected the normal pronuclear formation rates (p < 0.05). The incidence of polyspermy was high for β-ME (p < 0.05). No differences were observed in cleavage rates between treatments (p > 0.05). However, the developmental rate to the blastocyst stage was adversely affected by Cyst treatment (p < 0.05). The quality of embryos that reached the blastocyst stage, evaluated by total, inner cell mass (ICM) and trophectoderm cell numbers and ICM/total cell ratio was unaffected (p > 0.05) by treatments. The results indicate that ROS play a role in the fertilizing capacity in bovine spermatozoa, as well as in the interaction between the spermatozoa and the oocytes. It can be concluded that supplementation with antioxidants during IVF procedures impairs sperm quality, normal pronuclear formation and embryo development to the blastocyst stage.     

Participation of Opioid Peptides in Sucking‐induced Oxytocin and Prolactin Secretions in Lactating Goats

The role of opioid peptides in the secretion of oxytocin (OT) and prolactin (PRL) induced by sucking was studied in goats. Seven goats were isolated with their kids (four singletons and three twins) in individual corrals 3–4 weeks after parturition. On day 1 of the experiment, the kids were separated from the does for 7 h and were weighed before and 15 min after being reunited with their mothers to assess the amount of milk obtained by sucking. The does were blood‐sampled 10 min before and at the end of the sucking period. On day 2, a similar protocol was followed, but naloxone was given immediately after the first blood sample. On day 3, the protocol was repeated but saline vehicle was injected instead of naloxone. On day 5, the naloxone experiment was repeated as on day 2. Milk ejection was evaluated as the difference in the weight of the kids before and after sucking for 15 min, and the maternal serum levels of OT and PRL were measured by radioimmunoassay. A significant decrease in the weight gain of the kids was obtained when the mothers were treated with naloxone on day 2. Consistently, serum levels of OT and PRL induced by sucking were significantly reduced; indicating that sucking‐induced OT secretion for milk ejection in lactating goats is facilitated by opioid peptides. In a second experiment performed in the same animals 10 days later, the administration of OT, immediately after naloxone administration, prevented the decrease in the weight gain induced by naloxone, suggesting that the effect of the opioid antagonist on milk ejection in goats is a result of a reduced OT secretion. The results of this study confirm the importance of sucking‐induced OT secretion for milk ejection in lactating goats, and indicate that OT and PRL secretion are regulated by opioid peptides in this species.     

Estimates of (co)variance components and genetic parameters for growth traits of Avikalin sheep

(Co)variance components and genetic parameters for various growth traits of Avikalin sheep maintained at Central Sheep and Wool Research Institute, Avikanagar, Rajasthan, India, were estimated by Restricted Maximum Likelihood, fitting six animal models with various combinations of direct and maternal effects. Records of 3,840 animals descended from 257 sires and 1,194 dams were taken for this study over a period of 32 years (1977–2008). Direct heritability estimates (from best model as per likelihood ratio test) for weight at birth, weaning, 6 and 12 months of age, and average daily gain from birth to weaning, weaning to 6 months, and 6 to 12 months were 0.28 ± 0.03, 0.20 ± 0.03, 0.28 ± 0.07, 0.15 ± 0.04, 0.21 ± 0.03, 0.16 and 0.03 ± 0.03, respectively. Maternal heritability for traits declined as animal grows older and it was not at all evident at adult age and for post-weaning daily gain. Maternal permanent environmental effect (c ²) declined significantly with advancement of age of animal. A small effect of c ² on post-weaning weights was probably a carryover effect of pre-weaning maternal influence. A significant large negative genetic correlation was observed between direct and maternal genetic effects for all the traits, indicating antagonistic pleiotropy, which needs special care while formulating breeding plans. A fair rate of genetic progress seems possible in the flock by selection for all traits, but direct and maternal genetic correlation needs to be taken in to consideration.     

Digestibility and utilization of energy and protein in screened swine waste solids by gestating gilts

Two balance experiments were conducted using 24 gestating gilts in each experiment to determine the apparent digestible and metabolizable energy content, apparent digestible protein content, net protein utilization and apparent biological value of screened swine waste solids (SSWS). Waste solids were collected by screening flushed whole swine waste using a vibrating screen separator. Waste solids containing 30% dry matter were collected daily and mixed with a basal diet. In Exp. 1, SSWS were fed at a level estimated to replace 0, 25, 50 or 86% of the metabolizable energy content of the basal diet. Digestibility of the energy in the total diet decreased quadratically (85.2, 70.2, 60.7 and 58.3%, respectively, P less than .0001) with increasing SSWS. The percentages of gross energy supplied by SSWS that were digested and metabolized, as calculated by difference, were not affected significantly by the amount of SSWS fed (48.0, 48.0, 53.2% digested and 45.1, 45.2, 48.1% metabolized, respectively, for 25, 50 and 86% of gross energy intake from SSWS). The mean digestible and metabolizable energy contents of SSWS for gestating gilts were determined to be 1,998 and 1,854 kcal/kg dry matter. In Exp. 2, gilts were fed SSWS to replace 0, 25 or 50% of the crude protein in the basal diet. Apparent digestibility of the protein in the total diet decreased linearly (83.8, 66.1 and 51.1%, respectively, P less than .0001) as the amount of SSWS in the diet increased. The apparent digestibility of the crude protein in SSWS, as calculated by difference, was -4.23 and 10.1% for the 25 and 50% level of replacement.(ABSTRACT TRUNCATED AT 250 WORDS)     

Increases in ethylene and carbon dioxide production by Tulipa gesneriana L. ‘Prominence’ after completion of the cold-requirement

Bulbs of Tulipa gesneriana L. ‘Prominence’ were either specially pre-cooled at 5 ± 0.5°C or held at 17 ± 0.5°C in a flow-through system equipped for atmospheric sampling. Bulbs at 17°C had low CO₂ and C₂H₄ production rates until January when they began to increase. An initial peak of C₂H₄ production occurred during the 2nd week of pre-cooling, followed by a major increase after 12 weeks. In addition, bulbs were specially pre-cooled for periods of 2–16 weeks (2-week increments). The bulbs were then transferred to 17 ± 0.5°C, where initial periods of special pre-cooling of greater than 12 weeks resulted in a dramatic increase in respiration rate over bulbs cooled for less than 12 weeks. These increases in C₂H₄ and CO₂ liberation appeared to be related to completion of the bulb cold-requirement. However, no surge of shoot elongation occurred after 12 weeks of pre-cooling and transfer to 17°C.