An index of human alteration of lake shore morphology

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Image analysis and histochemistry to identify mobile stem resources for seed production in soybean

Resources for soybean [Glycine max (L.) Merr] pods are supplied initially from newly assimilated chemicals. As reproduction progresses, dependence on stored reserves increases. Seed weight is sensitive to stored shoot reserves, but the role of stem resources in late seed filling is unclear. Pith and cortex tissues contain living cells in stems and play a key role in storage. We hypothesized that main stem tissue composition can predict concentrations of mobilizable resources, which can be used to calculate impacts of mobilizable chemicals on yield. A field experiment with determinate cultivars investigated stem tissue composition, mobile and immobile chemicals, and their relationship with fruit production. Pith was correlated with non-structural chemicals; xylem and phloem predicted structural chemicals. During late seed filling, mobile stem chemicals decreased 67.5%, and we found a negative relationship between pith and aborted pods. Results support our hypotheses and highlight the importance of pith in remobilized resources for seed production in soybean.     

Differential expression of insulin‐like growth factor family members in immature cumulus–oocyte complexes from dairy cows with different genotypes

It has been evident the improvement of in vitro embryo production (IVEP) in dairy cows. Nevertheless, it is known that differences in the number and quality of oocytes between taurine and zebu females impact the efficiency and economic viability of IVEP. As the insulin‐like growth factor (IGF) system is related to follicular and oocyte development, we aimed to quantify mRNA abundance of IGF system members and pregnancy‐associated plasma protein‐A (PAPPA) in the cumulus–oocyte complexes (COCs) of Gir, 1/2 Holstein × 1/2 Gir and Holstein cows. Four pools of 30 immature COCs from Gir, 1/2 Holstein × 1/2 Gir and Holstein cows were obtained by ovum pickup (OPU), and the oocytes and cumulus cells (CC) were mechanically separated and stored at ?80°C. Total RNA was extracted from pools of 30 oocytes and their respective CC. Expression of target genes was assessed by real‐time RT‐PCR. In oocytes, the abundance of IGFR1 mRNA was higher (p < .05) in Gir cows compared with the other breeds. In contrast, in CC, mRNA encoding IGF2 (p < .05), IGFR2 (p < .05) and IGFBP4 (p < .01) was higher in Holstein donors compared with Gir and 1/2 Holstein × 1/2 Gir cows. Additionally, the abundance of PAPPA mRNA was higher in oocytes (p < .001) and CC (p < .01) in Gir and 1/2 Holstein × 1/2 Gir cows compared with the Holstein donors. In conclusion, the higher abundance of PAPPA mRNA in the oocytes and CC from Gir and cross‐breed donors combined with the low expression of IGFBP4 in the CC suggests an enhancement of the bioavailability of IGF‐free when compared with Holstein COCs.     

Comparison of plasma progesterone, transrectal ultrasound and pregnancy specific proteins (PSPB) used for pregnancy diagnosis in reindeer

The study aimed to compare plasma progesterone concentrations, rectal ultrasonography and plasma concentrations of pregnancy-specific protein B (PSPB) used for pregnancy diagnosis in reindeer. A total of 1,595 blood plasma samples were collected between 1991 and 1996 from 3 semidomestic reindeer (Rangifer tarandus tarandus) herds on the Norwegian mainland (Mager?y, S?r?y, Filefjell) and from 92 wild Svalbard reindeer (Rangifer tarandus platyrhynchus). Samples were collected between January and late April. Plasma levels of progesterone and PSPB were measured and used as indicators of pregnancy. In addition, animals from the Filefjell herd and the Svalbard reindeer were investigated using transrectal ultrasound. The results showed that plasma progesterone lower than 7 nmol l-1 rarely occurs in females diagnosed pregnant either by ultrasound or by observing a calf at foot 7 months after blood sampling. A very good agreement was found between plasma progesterone and PSPB when used for pregnancy diagnosis. On the Norwegian mainland, but not to the same extent on Svalbard, a high proportion of females with a high progesterone concentration was diagnosed not pregnant by ultrasound. This probably reflects a high rate of false negative diagnoses by the ultrasound method rather than false positives in the progesterone analysis.     

Effects of Gonadotrophin Releasing Hormone Administration on the Pituitary-Ovarian Axis in Anoestrous vs Ovariectomized Bitches

The aim of this study was to determine the effects of gonadotrophin releasing hormone (GnRH) administration on the plasma concentrations of reproductive hormones in intact and ovariectomized (OVX) bitches. Therefore, blood samples were collected at multiple times before and after the administration of 10 microg/kg GnRH (Fertagyl)) for the determination of the plasma concentrations of luteinizing hormone (LH), oestradiol, progesterone and testosterone in six anoestrus and in six OVX bitches. The mean plasma LH concentrations before and 60 min after GnRH administration were significantly lower in the anoestrous bitches than in the OVX bitches. In both groups GnRH administration resulted in a significant increase in the plasma LH concentration. The highest plasma LH concentrations were found at 10 min after GnRH administration and these values did not differ significantly between the two groups. Only in the anoestrous bitches a significant increase in plasma oestradiol concentrations was found after GnRH administration and these values were significantly higher than those in the OVX bitches. The plasma concentrations of progesterone and testosterone were low (close to or below the limit of quantitation) both before and after GnRH administration and the differences between anoestrous and OVX bitches were not significant. It can be concluded that (i) basal plasma LH concentration is significantly higher in OVX bitches than in anoestrous bitches, (ii) plasma LH concentration increases after GnRH administration in both anoestrous and OVX bitches, (iii) GnRH administration causes a significant rise in plasma oestradiol concentration only if ovarian tissue is present and (iv) measurement of plasma progesterone and testosterone concentrations before and after GnRH administration does not aid in distinguishing between anoestrous and OVX bitches. The results of this study may provide a basis for the diagnosis of remnant ovarian tissue and verification of neuter status in the bitch.     

The response of Pinus sylvestris to drought: stomatal control of transpiration and hydraulic conductance

We investigated the impact of drought on the physiology of 41-year-old Scots pine (Pinus sylvestris L.) in central Scotland. Measurements were made of the seasonal course of transpiration, canopy stomatal conductance, needle water potential, xylem water content, soil-to-needle hydraulic resistance, and growth. Comparison was made between drought-treated plots and those receiving average precipitation. In response to drought, transpiration rate declined once volumetric water content (VWC) over the top 20 cm of soil reached a threshold value of 12%. Thereafter, transpiration was a near linear function of soil water content. As the soil water deficit developed, the hydraulic resistance between soil and needles increased by a factor of three as predawn needle water potential declined from -0.54 to -0.71 MPa. A small but significant increase in xylem embolism was detected in 1-year-old shoots. Stomatal control of transpiration prevented needle water potential from declining below -1.5 MPa. Basal area, and shoot and needle growth were significantly reduced in the drought treatment. In the year following the drought, canopy stomatal conductance and soil-to-needle hydraulic resistance recovered. Current-year needle extension recovered, but a significant reduction in basal area increment was evident one year after the drought. The results suggest that, in response to soil water deficit, mature Scots pine closes its stomata sufficiently to prevent the development of substantial xylem embolism. Reduced growth in the year after a severe soil water deficit is most likely to be the result of reduced assimilation in the year of the drought, rather than to any residual embolism carried over from one year to the next.     

Pregnancy Rates to Fixed Embryo Transfer of Vitrified IVP Bos indicus,Bos taurus or Bos indicus × Bos taurus Embryos

The pregnancy rates obtained after the transfer of cryopreserved in vitro‐produced (IVP) embryos are usually low and/or inconsistent. The objective of this study was to evaluate the pregnancy rates of Holstein, Gyr and Holstein × Gyr cattle after the transfer of vitrified IVP embryos produced with X‐sorted sperm. Seventy‐two Gyr and 703 Holstein females were subjected to ovum pickup (OPU) sessions, followed by in vitro embryo production using semen from sires of the same breeds. Embryos (1636 Holstein, 241 Gyr and 1515 Holstein × Gyr) were exposed to forskolin for 48 h prior to vitrification. The pregnancy rate achieved with Gyr dam and sire was 46.1%, which was similar (p = 0.11) to that of Holstein dam and Gyr sire (40.3%). Crossing Gyr dams with Holstein sires resulted in a pregnancy rate of 38.9% and did not differ (p = 0.58) from the pregnancy rate obtained with the cross between Holstein dams and Gyr sires. The rate obtained with Holstein dam and sire was 32.5%. The average pregnancy rate was 36.6%, and no difference was found in the proportion of female foetuses (88.8%, in average) among breeds (p > 0.05). In conclusion, transfer of cryopreserved X‐sorted embryos represents an interesting choice for dairy cattle. Despite the small differences between pregnancy rates, we highlight the efficiency of this strategy for all of the racial groups studied.     

Effects of FGF10 on Bovine Oocyte Meiosis Progression,Apoptosis, Embryo Development and Relative Abundance of Developmentally Important Genes In Vitro

Fibroblast growth factor (FGF10) acts at the cumulus oocyte complex, increasing the expression of cumulus cell expansion‐related genes and oocyte competency genes. We tested the hypothesis that addition of FGF10 to the maturation medium improves oocyte maturation, decreases the percentage of apoptotic oocytes and increases development to the blastocyst stage while increasing the relative abundance of developmentally important genes (COX2, CDX2 and PLAC8). In all experiments, oocytes were matured for 22 h in TCM‐199 supplemented with 0, 2.5, 10 or 50 ng/ml FGF10. In Experiment 1, after maturation, oocytes were stained with Hoechst to evaluate meiosis progression (metaphase I, intermediary phases and extrusion of the first polar body) and submitted to the TUNEL assay to evaluate apoptosis. In Experiment 2, oocytes were fertilized and cultured to the blastocyst stage. Blastocysts were frozen for analysis of COX2, CDX2 and PLAC8 relative abundance. In Experiment 1, 2.5 ng/ml FGF10 increased (p < 0.05) the percentage of oocytes with extrusion of the first polar body (35%) compared to 0, 10 and 50 ng/ml FGF10 (21, 14 and 12%, respectively) and FGF10 decreased the percentage of oocytes that were TUNEL positive in all doses studied. In Experiment 2, there was no difference in the percentage of oocytes becoming blastocysts between treatments and control. Real‐time RT‐PCR showed a tendency of 50 ng/ml FGF10 to increase the relative abundance of COX2 and PLAC8 and of 10 ng/ml FGF10 to increase CDX2. In conclusion, the addition of FGF10 to the oocyte maturation medium improves oocyte maturation in vitro, decreases the percentage of apoptotic oocytes and tends to increase the relative abundance of developmentally important genes.