Plastid genomes reveal evolutionary shifts in elevational range and flowering time of Osmanthus (Oleaceae)

Species of Osmanthus are economically important ornamental trees, yet information regarding their plastid genomes (plastomes) have rarely been reported, thus hindering taxonomic and evolutionary studies of this small but enigmatic genus. Here, we performed comparative genomics and evolutionary analyses on plastomes of 16 of the 28 currently accepted species, with 11 plastomes newly sequenced. Phylogenetic studies identified four main lineages within the genus that are here designated the: “Caucasian Osmanthus” (corresponding to O. decorus), “Siphosmanthus” (corresponding to O. sect. Siphosmanthus), “O. serrulatus + O. yunnanensis,” and “Core Osmanthus: (corresponding to O. sect. Osmanthus + O. sect. Linocieroides). Molecular clock analysis suggested that Osmanthus split from its sister clade c. 15.83 Ma. The estimated crown ages of the lineages were the following: genus Osmanthus at 12.66 Ma; “Siphosmanthus” clade at 5.85 Ma; “O. serrulatus + O. yunnanensis” at 4.89 Ma; and “Core Osmanthus: clade at 6.2 Ma. Ancestral state reconstructions and trait mapping showed that ancestors of Osmanthus were spring flowering and originated at lower elevations. Phylogenetic principal component analysis clearly distinguished spring‐flowering species from autumn‐flowering species, suggesting that flowering time differentiation is related to the difference in ecological niches. Nucleotide substitution rates of 80 common genes showed slow evolutionary pace and low nucleotide variations, all genes being subjected to purifying selection.

Evolutionary patterns of nucleotide substitution rates in plastid genomes of Quercus

Molecular evolution, including nucleotide substitutions, plays an important role in understanding the dynamics and mechanisms of species evolution. Here, we sequenced whole plastid genomes (plastomes) of Quercus fabri, Quercus semecarpifolia, Quercus engleriana, and Quercus phellos and compared them with 14 other Quercus plastomes to explore their evolutionary relationships using 67 shared protein-coding sequences. While many previously identified evolutionary relationships were found, our findings do not support previous research which retrieve Quercus subg. Cerris sect. Ilex as a monophyletic group, with sect. Ilex found to be polyphyletic and composed of three strongly supported lineages inserted between sections Cerris and Cyclobalanposis. Compared with gymnosperms, Quercus plastomes showed higher evolutionary rates (Dn/Ds = 0.3793). Most protein-coding genes experienced relaxed purifying selection, and the high Dn value (0.1927) indicated that gene functions adjusted to environmental changes effectively. Our findings suggest that gene interval regions play an important role in Quercus evolution. We detected greater variation in the intergenic regions (trnH-psbA, trnK_UUU-rps16, trnfM_CAU-rps14, trnS_GCU-trnG_GCC, and atpF-atpH), intron losses (petB and petD), and pseudogene loss and degradation (ycf15). Additionally, the loss of some genes suggested the existence of gene exchanges between plastid and nuclear genomes, which affects the evolutionary rate of the former. However, the connective mechanism between these two genomes is still unclear.

Stress caused by laparoscopy in sheep and its alleviation

AIM

To determine the plasma cortisol response to laparoscopy in ewes and investigate means of reducing it.

METHODS

Ewes without lambs at foot (n=40) were subjected to one of three control or one laparoscopy treatments (n=10 ewes/treatment), being: no restraint or drugs; acepromazine maleate (ACP) control and no restraint; ACP and restraint in a cradle for 5 min; and laparoscopy following ACP. Additional ewes with lambs at foot (n=30) were subjected to: laparoscopy following ACP; laparoscopy following ACP and ketoprofen; and laparoscopy following detomidine. Drugs were injected 20 min before treatment, after a first blood sample had been taken. Blood samples were taken by jugular venepuncture from the ewes 20 min before treatment and at 20, 40, 60, 90, 120, 150 and 180 min after treatment, while all ewes were held in a pen. Plasma was harvested and assayed for its concentration of cortisol.

RESULTS

Plasma cortisol concentrations (PCC) remained constant in ewes in the control restraint group for 80 min. In ewes given ACP, PCC increased for the first 20 min after treatment but then returned to pre-treatment concentrations. PCC of ewes given ACP and restrained in a cradle were elevated above pre-treatment concentrations for 90 min. PCC in ewes subjected to laparoscopy following sedation with ACP increased to a peak at 40 min and returned to pre-treatment concentrations after 60 (with lambs) or 120 (without lambs) min. When ACP and ketoprofen were given before laparoscopy, PCC peaked at 20 min and returned to pre-treatment concentrations by 40 min. PCC of ewes given detomidine before laparoscopy remained at pre-treatment concentrations throughout. PCC of ewes subjected to laparoscopy with ACP sedation only were greater than those of control restraint, ACP control, and ewes subjected to laparoscopy after being given ketoprofen or detomidine between 20 and 60 min after treatment. PCC of ewes subjected to laparoscopy were greater than those of control ewes placed in a cradle at 20 and 40 min. PCC of ewes given ketoprofen were lower than those of ewes subject to laparoscopy following ACP.

CONCLUSIONS

Laparoscopy, even after sedation with ACP, caused some distress in ewes, as evidenced by increased plasma cortisol levels. Plasma cortisol response was alleviated by the administration of ketoprofen and eliminated by detomidine, probably because of both analgesic and sedative effects of the latter drug.

Effects of age on the electroencephalographic response to castration in lambs anaesthetised using halothane in oxygen

AIM

To use the electroencephalogram (EEG) to ascertain whether the response of the cerebral cortex to the noxious stimulus of castration varied with age in lambs.

METHODS

Two groups of East Friesian lambs were selected according to age; the mean age of the younger group (n=21) was 12 (SD 2) days and the older group (n=20) was 29 (SD 1) days. Anaesthesia was induced via mask using 4% halothane in oxygen, and maintained using 1.5% halothane in oxygen at a flow rate of 4 L/min. Once a stable plane of anaesthesia had been achieved, data collection of EEG and electrocardiographic (ECG) readings commenced, and the lambs were castrated 15 min later, using rubber rings. Median and 95% spectral edge frequencies (F95) and total EEG power (ptot) were derived from data from the EEG.

RESULTS

Following castration, there was an increase in the median frequency (F50) in the younger lambs (p=0.002), and an increase in ptot in both groups (p=0.05), which was of greater magnitude in the older lambs. There were no significant changes in the F95. Both younger and older lambs exhibited a transient bradycardia (p=0.001 and p=0.01, respectively).

CONCLUSIONS

These differences in the cortical response between the two groups suggest that 2-week-old lambs undergo a qualitatively different perception of the noxious stimulus of castration compared to 4-week-old lambs.

Behavioural responses of calves to amputation dehorning with and without local anaesthesia

OBJECTIVE

To assess the pain elicited by amputation dehorning and evaluate the effect of local anaesthesia by using changes in calf behaviour.

METHODS

The behaviour of 6-month-old Friesian calves (n = 60), subjected to control handling, dehorned or dehorned after local anaesthesia treatment, was monitored in this study. The proportion of calves displaying particular behaviours was recorded using instantaneous scan sampling during the first 10 h and between 26 and 29 h after treatment.

RESULTS

The three behaviours of tail flicking, head shaking and ear flicking displayed similar features with time according to treatment and appeared to occur in an inverse relation to rumination. Dehorned calves were highly restless for the first 6 h after treatment. A significantly greater proportion of them displayed tail flicking, head shaking and ear flicking than the control calves, which, by contrast, stood still and ruminated (P < 0.05). The behaviour of calves given local anaesthetic prior to dehorning was similar to that of the control calves for the first 2 h. Thereafter the proportion of calves displaying tail flicking, head shaking and ear flicking increased, rumination decreased, and the behaviour was similar to that of the dehorned calves.

CONCLUSIONS

These results suggest that dehorning is a painful experience that lasts about 6 h and that local anaesthetic alleviates that pain during its period of action. It is recommended that local anaesthetic be administered when conducting amputation dehorning.

Acute cortisol responses of calves to four methods of dehorning by amputation

OBJECTIVE

To measure the plasma cortisol response in calves dehorned by four different methods (scoop, guillotine shears, saw, embryotomy wire) for 9 h after dehorning.

DESIGN

A physiological study with controls.

PROCEDURE

Horn amputation was carried out on calves restrained manually in a race.

RESULTS

The four methods of dehorning provoked similarly increased cortisol responses which lasted for 6 h. During the first hour after dehorning the plasma cortisol concentrations were similar to those following ACTH injection. The overall cortisol response to control handling was about 30% of the responses to dehorning.

CONCLUSIONS

The similarity of the cortisol responses produced by the four methods of dehorning suggests that the distress experienced by calves following dehorning by amputation is similar regardless of method used.

Acute cortisol responses of calves to scoop dehorning using local anaesthesia and/or cautery of the wound

OBJECTIVE

To measure plasma cortisol responses in calves dehorned using a scoop after administration of local anaesthesia and/or cautery of the wounds.

DESIGN

A physiological study with controls.

PROCEDURE

There were six treatments: control handling with and without local anaesthesia, dehorning, dehorning after local anaesthesia, dehorning followed by wound cautery, and dehorning after local anaesthesia followed by wound cautery. Blood samples were taken before and after dehorning.

RESULTS

Dehorning caused an increase in plasma cortisol concentrations, which decreased a little to plateau values and then declined to pretreatment values 3 to 4 h after dehorning. The peak was smaller after local anaesthesia was administered but when its effects wore off, cortisol concentrations increased and thereafter were similar to those in the dehorned animals. The combination of local anaesthesia and cautery resulted in a plasma cortisol response similar to those in control calves with or without local anaesthesia.

CONCLUSIONS

If plasma cortisol concentrations reflect the distress being experienced by the calves, then local anaesthesia reduces the acute distress for about 3 h after dehorning but not during the subsequent 3 to 4 h. Combining local anaesthetic and cautery prevented the significant increase in plasma cortisol following dehorning and may eliminate the acute distress caused by scoop dehorning.