Functional roles of ornithine decarboxylase and arginine decarboxylase during the peri-implantation period of pregnancy in sheep

Background: Polyamines stimulate DNA transcription and m RNA translation for protein synthesis in trophectoderm cells, as well as proliferation and migration of cells; therefore, they are essential for development and survival of conceptuses(embryo/fetus and placenta). The ovine conceptus produces polyamines via classical and non-classical pathways. In the classical pathway, arginine(Arg) is transformed into ornithine, which is then decarboxylated by ornithine decarboxylase(ODC1) to produce putrescine which is the substrate for the production of spermidine and spermine. In the non-classical pathway, Arg is converted to agmatine(Agm) by arginine decarboxylase(ADC), and Agm is converted to putrescine by agmatinase(AGMAT).Methods: Morpholino antisense oligonucleotides(MAOs) were designed and synthesized to inhibit translational initiation of the m RNAs for ODC1 and ADC, in ovine conceptuses.Results: The morphologies of MAO control, MAO-ODC1, and MAO-ADC conceptuses were normal. Double knockdown of ODC1 and ADC(MAO-ODC1:ADC) resulted in two phenotypes of conceptuses; 33% of conceptuses appeared to be morphological y and functional y normal(phenotype a) and 67% of the conceptuses presented an abnormal morphology and functionality(phenotype b). Furthermore, MAO-ODC1:ADC(a) conceptuses had greater tissue concentrations of Agm,putrescine, and spermidine than MAO control conceptuses, while MAO-ODC1:ADC(b) conceptuses only had greater tissue concentrations of Agm. Uterine flushes from ewes with MAO-ODC1:ADC(a) had greater amounts of arginine, aspartate, tyrosine, citrulline, lysine, phenylalanine, isoleucine, leucine, and glutamine, while uterine flushes of ewes with MAO-ODC1:ADC(b) conceptuses had lower amount of putrescine, spermidine, spermine, alanine, aspartate,glutamine, tyrosine, phenylalanine, isoleucine, leucine, and lysine.Conclusions: The double-knockdown of translation of ODC1 and ADC m RNAs was most detrimental to conceptus development and their production of interferon tau(IFNT). Agm, polyamines, amino acids, and adequate secretion of IFNT are critical for establishment and maintenance of pregnancy during the peri-implantation period of gestation in sheep.

Growth and yield of nine pine species in Angola

A species introduction experiment including several tropical pines and eucalypts was established in 1966/1967 in the Tchianga research station in Angolan Highlands. Despite 27 years of political conflict （1975-2002） and lack of management, the research experiment has remained relatively well conserved. We measured the best conserved plots that were 41 years old in 2007 to obtain information on the growth of different pine species. We calculated stand characteristics including basal area, dominant height, mean diameter, and stand volume for Pinus patula Schiede ex Schiltdl. Et Cham., Pinus pseudostrobus Lindl., Pinus kesiya Royle ex Gordon, Pinus devoniana Lindl., Pinus chiapensis （Martinez） Andresen, Pinus elliottii Engelm., Pinus greggii Engelm. Ex Parl., Pinus montezumae Lamb. and Pinus oocarpa Schiede ex Schltdl. The growing stock volume at 41 years was the highest in P. pseudostrobus, 1,325 m3^· ha^-1, followed by P. kesiya with 1,200 m^3· ha^-1. The widely planted P. patula had growing stock volume of 892 m^3· ha-^1. P. oocarpa and P. pseudostrobus had the highest stand basal area, over 80 m^2·ha^-1. Using increment core analyses we studied the temporal development of stand characteristics. Analysis of the mean annual increment （MAI） showed that rotation lengths of 20-30 years would maximize wood production. With these rotation lengths, the MAI of P. pseudostrobus would be 35 m^3· ha^-1. Other productive species were P. kesiya, P. ooearpa and P. chiapensis. P. patula had a maximum MAI of 20 m^3· ha^-1. P. greggii had the lowest mean annual volume production, only about 13 m^3· ha^-1.

Morphophysiological responses of forest seedling species subjected to different water regimes

Water availability is a limiting factor for the establishment and development of forest species.To understand the appropriate conditions for the initial post-transplanting phase,it is necessary to understand the specific morphophysiological characteristics of the species,such as the leaf water potential and the efficiency of photosystemⅡ.We aimed to identify the influence of different water regimes on the morphophysiological aspects of young plants of two forest species(Cedrela.fissilis Vellozo and Eucalyptus saligna Sm.).Two greenhouse experiments were conducted for 28 days;one for each species.The design was completely randomized,and the treatments consisted of six different water regimes.Leaf water potential(Ψw)and chlorophyll a fluorescence were evaluated every 7 days.At the end of the experiment,morphological attributes(height,collection diameter,root volume,and dry matter)were measured and histological blades were made.The water demand of E.saligna was higher than that of C.fissilis and required greater replacement within a shorter period.The rehydration fromΨw=-2 Mpa allowed for a fast recovery of the young C.fissilis plants(Ψw=-1.5,Fv/Fm=0.796),which indicated good physiological plasticity of this species when submitted to water stress at a level that is not severe.The total dry matter allocation was different among species.Seedlings of E.saligna presented the best responses when submitted to a continuous water supply regime,while C.fissilis seedlings presented the best response under intermittent irrigation conditions.

Root proliferation in native perennial grasses of arid Patagonia,Argentina

Pappophorum vaginatum is the most abundant C4 perennial grass desirable to livestock in rangelands of northeastern Patagonia, Argentina. We hypothesized that （1） defoliation reduce net primary productivity, and root length density and weight in the native species, and （2） root net primary productivity, and root length density and weight, are greater in P. vaginatum than in the other, less desirable, native species （i.e., Aristida spegazzinfi, A. subulata and Sporobolus cryptandrus）. Plants of all species were either exposed or not to a severe defoliation twice a year during two growing seasons. Root proliferation was measured using the cylinder method. Cylindrical, iron structures, wrapped up using nylon mesh, were buried diagonally from the periphery to the center on individual plants. These structures, initially filled with soil without any organic residue, were dug up from the soil on 25 April 2008, after two successive defoliations in mid-spring 2007. During the second growing season （2008-2009）, cylinders were destructively harvested on 4 April 2009, after one or two defoliations in mid- and/or late-spring, respectively. Roots grown into the cylinders were obtained after washing the soil manually. Defoliation during two successive years did reduce the study variables only after plants of all species were defoliated twice, which supported the first hypothesis. The greater root net primary productivity, root length den- sity and weight in P. vaginatum than in the other native species, in support of the second hypothesis, could help to explain its greater abundance in rangelands of Argentina.

<i>In Vitro</i>Priming of Sugarcane Varieties (RB966928 and RB867515)

Sugarcane, as a glycophyte, shows sensitivity to saline soils at various stages of its growth. The aim of this study was to evaluate the in vitro priming response in two sugarcane varieties (RB966928 and RB867515). Micropropagated plants, from meristems, received priming treatments by adding the salts (NaCl and KCl) in different concentrations (0.0;12.5;25.0 and 50.0 mM), in the MS medium. Subsequently, the plants were cultivated in rooting medium without addition of salts, acclimatized and submitted to gradient ex vitro saline stress with 20 → 40 and 60 mM, of each salt, for 30 days. The analyzed variables were dry matter of shoot and root, number of tillers and estimation of chlorophyll content. The experiment was carried out in a 2 × 2 × 4 factorial arrangement, in a completely randomized experimental design. Twenty replicates were used throughout the experiment. Data were submitted to analysis of variance and regression and the means were compared by Tukey’s test, at a 5% probability level. The priming treatments presented a significant effect, with triple interaction, in the chlorophyll index. In the treatment with NaCl, the variety RB966928 showed an increase in the chlorophyll index with the increase of treatment levels, up to an optimal limit of 31.47 mM. On the other hand, the variety RB867515 showed decreasing in chlorophyll index. In contrast, in KCl treatment, the variety RB867515 presented the increase at the chlorophyll index with the maximum point of 25 mM. For the variables, shoot dry matter (SDM) and root dry matter (RDM) there was a significant difference (p 0.05 and p 0.01, respectively) only between the varieties. The variety RB966928 presented higher SDM and RDM in relation to the variety RB867515. Studies are recommended with increasing the duration of the priming treatments and more detailed study of the culture throughout its productive cycle.

Germination of Sweet Sorghum Seeds in Different Water Potentials

The implantation of sweet sorghum has been shown as viable alternative in crop rotation in sugar cane plantation reform areas. The seed environment in the field is complex and several factors, such as different genotypes and osmotic stress, can negatively influence the seeds water uptake and, therefore, the sequence of germination events can be compromised. In this context, the objective of this study was to evaluate the different physiological responses of sweet sorghum seeds (Sorghum bicolor (L.) Moench) belonging to the hybrids CV 007 and CV 147 and cultivar BRS 506 when submitted to substrates with different water potentials (-0.1, -0.2, -0.3, -0.4, and -0.5 MPa) using solutions of polyethylene glycol (PEG 6000). The seeds remained in Biochemical Oxygen Demand-type germination chambers, under constant white light and the temperature of 25°C for 14 h in the high temperature and 10 h in the low temperature. The moisture of the substrates was regularly monitored. The physiological potential of the genotypes was evaluated using the following characteristics: first count, germination, germination speed index (GSI), root length, and fresh and dry weights of seedlings. In general, germination and early growth of seedlings were negatively affected by the reduction of water potentials below -0.1 MPa, which was also damaging to the GSI of the seeds. Germination and growth of seedlings of the hybrids CV 007 and CV 147 and of the cultivar BRS 506 were affected by reduced water potentials starting at -0.1 MPa. The seeds of hybrid CV 147 were more tolerant to simulated water stress with PEG 6000 than those of hybrid CV 007 and cultivar BRS 506.

Reduced Sensitivity of Campomanesia adamantium(Cambess.)O.Berg Seeds to Desiccation:Effects of Polyethylene Glycol and Abscisic Acid

The Campomanesia adamantium is a threatened species from Brazil Savannah which seeds are desiccation-sensitive and do not withstand storage. This study aimed to reduce the sensitivity of Campomanesia adamantium seeds to desiccation using polyethylene glycol (PEG) and abscisic acid (ABA). Initially, seeds were subjected to PEG (0, -1.48, and -2.04 MPa) with or without ABA (100 μM) during 120 h, followed fast drying (silica gel) or slow drying (laboratory environment), at 20%, 15%, and 10% moisture content. In the second experiment, the seeds were PEG treated (-1.48 MPa) which provided the best results in the first experiment;the seeds were then subjected to different incubation times in PEG (30, 60, 90, or 120 h) and ABA (0, 10ˉ3, 10ˉ4, and 10ˉ5 μM), following the seeds were fast dried at 15% moisture content. The slow drying should be avoided, even in seeds previously subjected to osmotic conditioning with or without ABA. Seeds submitted to PEG treatment (-1.48 MPa/120h) without ABA and PEG (-1.48 MPa) with 10ˉ3 or 10ˉ4 μM of ABA (90 h), followed by fast drying at 15% moisture content showed reduction of desiccation sensitivity and high germination and vigor when compared to the other treatments.

Reproductive Trends in Cebu Cattle Grazing Rice Crop Residues in Colombian Tropical Dry Forest

The objective of this study was to describe the trend of reproductive performance of primiparous and multiparous cows that grazed rice crop residues located in a Dry Tropical Forest of Colombia, taking into account the rainfall pattern of the place. In this study, 89 primiparous and 309 multiparous Cebu cattle records were analyzed. Mean, mean standard deviation for age at first calving and open days of primipar-ous Cebu cattle were 41.05± 1.85 months and 269.7±36.25 days respectively. Confidence intervals (95%) for both reproductive parameters were 36.8-45.3 months and 202.7-336.6 days respectively. For multiparous Cebu cattle, the mean and mean standard deviation for open days and calving interval were 245.6±36.8 days and 17.5±0.9 months respectively. Confidence intervals 207.1-366.9 days and 13.9-20.7 months respectively. The mean rainfall since 1999 until 2012 was1202 mmper year. The reproduc-tive trend of the primiparous cattle showed an increasing behavior of age at first calving since 1999 until 2012, that can possibly be explained due to the decreasing behavior of the rainfall throughout the years, that can affect the nutritional value and offer of the grass that can grow in the borders of the crop, such as Guinea and Star grass, and eventually affect the body condition and weight necessary to be ready for the first estrous. An inverse behavior of open days occurred, showing a decreased trend along the last years of research. This fact could have happened due to the intensive use of the enriched rice straw with urea and molasses lately. Regarding to the reproductive trend of the multiparous cattle, there is no an evident pat-tern of it. Factors such as rainfall, temperature, nutrition and management should have affected it. Further research on this topic is needed.