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1.
Our aim was to determine the frequency and characteristics of a fractionated pattern of diaphragm and upper airway muscle activity and airflow during wakefulness and sleep in adult goats. A fractionated breath (FBr) was defined as three or more brief (40-150 ms) interruptions in the diaphragm activity not associated with multiple swallows, eructation, mastication, or movement. During a FBr, the discharge pattern in the diaphragm and upper airway muscles showed complete cycles of inspiration and expiration. Whereas the interval between peak diaphragm activity of the breath preceding the FBr to the first diaphragm peak of the FBr was 15-20% less than the average interval of the preceding five control breaths, the breath-to-breath interval of the five breaths after a FBr did not differ from the control breaths before the FBr event. In normal goats, FBr was evident in only 4 of 18 (22%) awake goats and in only one of these goats during non-rapid eye movement sleep. In 35 goats with implanted microtubules in the medulla, FBr were present in 14 (40%) goats. In these goats with FBr, 78% (11 of 14) had one or more implantations into or near the facial, vestibular, or raphe nuclei. The effect of perturbations in these nuclei is probably nonspecific, because injections into these nuclei with mock cerebrospinal fluid or excitatory amino acid-receptor agonist or antagonist produced both increases and decreases in the frequency of the FBr while not altering their characteristics. Finally, a swallow occurred at the termination or during the first breath after 60% of the FBr. We speculate that the FBr manifest 1) the disruption of a neuronal network, which coordinates breathing and other functions (such as swallowing), utilizing the same anatomic structures, and/or 2) transient changes in synaptic inputs that increase the rate of the normal respiratory rhythm generator or allow an ectopic, anomalous generator to become dominant.  相似文献   
2.
Studies were conducted to investigate the effects of a kaolin-based hydrophilic particle film, Surround WP, on the biology and behavior of the psyllid Diaphorina citri Kuwayama (Hemiptera: Psyllidae) and to assess population densities of D. citri in citrus subjected to monthly applications of Surround WP. Laboratory investigations indicated a 3% (wt:vol) suspension of Surround WP in water applied directly was not acutely toxic to eggs, older nymphs or adults. Presence of the dried particle film on leaves interfered with the ability of adults to grasp and walk on citrus leaves. During a 30-s period, adults spent an average of 5 s moving on leaves with particle film compared with 16 s on leaves without particle film. When leaves were inverted, a significantly higher percentage of adults fell or flew from treated leaves (53%) than untreated leaves (16%). In a 12-mo study investigating infestations of D. citri on citrus treated monthly with Surround WP, cumulative reductions of 78% in adult numbers on mature leaves and of 60% in adult numbers on flush shoots (immature leaves) were observed in treated trees compared with untreated trees. Numbers of eggs and nymphs per flush shoot were reduced by 85 and 78%, respectively, in trees treated with particle film. Reductions in infestation levels of D. citri in treated trees were attributed to the negative effects of the particle film on the ability of adults to grasp, move, and oviposit. The suppressive effects of a Surround treatment against adult psyllids were degraded by rain.  相似文献   
3.
1 Although management of the oriental beetle Anomala orientalis (Waterhouse) by mating disruption shows promise across a range of agricultural systems, relatively little is known about aspects of the reproductive biology of this species relevant to its management. We studied the effects of delayed mating on several aspects of the oviposition behaviour and biology of the oriental beetle using females mated in the laboratory at 4–13 days posteclosion. 2 Females exhibited a gradual decline in fecundity with increased age at mating that was largely a function of a decline in duration of the oviposition period, as well as lower female fertility: females mated at 11 days were less likely to lay any fertile eggs. However, egg fertility did not vary with female age at mating. 3 Because mating delay did not affect longevity, females mated at older ages experienced decreased oviposition periods; however, females laid more eggs per day with increased age at mating, which partially offset shorter oviposition periods. 4 A mating delay of ≥ 6 days relative to females mated within the first day of reaching sexual maturity resulted in an approximately 35–50% lower mean fecundity. 5 These results suggest that, for mating disruption to be a successful management tool for the oriental beetle, mating must be prevented rather than delayed. We compare the findings of the present study with the published research on delayed mating in moths and discuss the importance of these results in relation to management of the oriental beetle using female sex pheromones.  相似文献   
4.
The purpose of these studies was to test the hypothesis that carotid chemoreceptor activity is necessary for postnatal maturation of the ventilatory control system. By using a lateral surgical access, 17 piglets were carotid body denervated (CBD) and 14 were sham denervated at 3-25 days of age. After surgery, there was no irregular breathing in any group. There was no significant hypoventilation when CBD was performed at less than 5 days of age (n = 5) and only a mild (arterial PCO(2) 5 Torr; P < 0.05) to moderate, transient (arterial PCO(2) 8 Torr; P < 0.5) hypoventilation in piglets denervated at 10-15 (n = 6) and 20-25 (n = 6) days of age, respectively. Three weeks after surgery, both breathing of a hypoxic gas mixture and jugular venous NaCN injections elicited a hyperpnea in the CBD piglets that was attenuated compared with that in sham CBD piglets. In the CBD piglets, there was no response to injections of NaCN in the carotid arteries, but there was a response to NaCN injected into the proximal descending aorta, suggesting the residual peripheral chemosensitivity was of aortic origin. Carotid chemoreceptor-intact piglets had carotid and aortic NaCN chemosensitivity by 2 days of age. The carotid response persisted for the 40 days of the study, but the aortic reflex persisted only until approximately 8 days of age. We conclude that 1) the major effect of CBD per se in neonatal piglets is age-dependent hypoventilation and 2) there is a high degree of plasticity in peripheral chemosensitivity in neonates that may contribute to minimizing the changes in breathing after CBD.  相似文献   
5.
Although the frequently large variance in relative male fertilizationsuccess when females are mated by more than 1 male has beenappreciated for some time, the factors that influence relativepaternity are still poorly understood. Recently, experimentalevidence that morphology of male genitalia influences fertilizationsuccess has been documented in 2 water striders, a dung beetle,and a leaf beetle. We explored the role of male genital morphologyin postcopulatory sexual selection in the oriental beetle. Wemated females to 2 males in succession and assessed relativepaternity by the sterile male technique. Morphology of the malegenitalia was found to strongly influence relative paternitybut only for the first male to mate. Male body size influencedrelative fertilization success as well, but again, only forthe first male; surprisingly, smaller males achieved higherpaternity when mating first. We also found suggestive evidencethat copula duration of both the first and second male to mateinfluenced paternity. Other factors, including female size anddegree of asymmetry of hind tibiae length of males had no effecton relative fertilization success. Our results for the orientalbeetle are novel among sperm precedence studies for 2 reasons:1) traits of the first male appear to be more important in influencingpaternity than those of the second, and 2) smaller, not larger,males achieved greater relative paternity. Our results alsocontribute to the growing body of empirical evidence in supportof the hypothesis that male genitalia evolve by postcopulatorysexual selection.  相似文献   
6.
Abstract

Enhanced cellular uptake, stable and discriminating hybridization and increased stability in biological media are of particular interest for oligonucleotides of potential therapeutic application. Additionally, toxicity or immunogenicity of the oligonucleotide analogues and their biodegradation products should be minimized by minimal alteration of the biological structure and effort and cost of bulk production should be as low as possible by using a standard automated synthesis protocol. Oligonucleotide phosphotriesters with oligoethyleneglycol substituents show promise to ideally combine all these advantages. Here we describe the hybridization properties and the stability of modified oligonucleotides containing triester internucleotide linkages substituted with α,ω-dihydroxy-(3,6-dioxa)-octan-1-yl group (“triethyleneglycol triester linkages”) towards enzymatic degradation. The triester linkages are stable towards exo- and endonucleases. Regardless of number and position of triester linkages, the modified oligonucleotides showed practically no decrease of Tm in hybridization studies with complementary biological oligonucleotides. In further enzymatic studies the modified oligonucleotides were highly stable towards nucleases in human blood serum.  相似文献   
7.
Brain stem preparations from adult turtles were used to determine how bath-applied serotonin (5-HT) alters respiration-related hypoglossal activity in a mature vertebrate. 5-HT (5-20 microM) reversibly decreased integrated burst amplitude by approximately 45% (P < 0.05); burst frequency decreased in a dose-dependent manner with 20 microM abolishing bursts in 9 of 13 preparations (P < 0.05). These 5-HT-dependent effects were mimicked by application of a 5-HT(1A) agonist, but not a 5-HT(1B) agonist, and were abolished by the broad-spectrum 5-HT antagonist, methiothepin. During 5-HT (20 microM) washout, frequency rebounded to levels above the original baseline for 40 min (P < 0.05) and remained above baseline for 2 h. A 5-HT(3) antagonist (tropesitron) blocked the post-5-HT rebound and persistent frequency increase. A 5-HT(3) agonist (phenylbiguanide) increased frequency during and after bath application (P < 0.05). When phenylbiguanide was applied to the brain stem of brain stem/spinal cord preparations, there was a persistent frequency increase (P < 0.05), but neither spinal-expiratory nor -inspiratory burst amplitude were altered. The 5-HT(3) receptor-dependent persistent frequency increase represents a unique model of plasticity in vertebrate rhythm generation.  相似文献   
8.
In awake goats, 29% bilateral destruction of neurokinin-1 receptor-expressing neurons in the pre-B?tzinger complex (pre-B?tzC) area with saporin conjugated to substance P results in transient disruptions of the normal pattern of eupneic respiratory muscle activation (Wenninger JM, Pan LG, Klum L, Leekley T, Bastastic J, Hodges MR, Feroah T, Davis S, and Forster HV. J Appl Physiol 97: 1620-1628, 2004). Therefore, the purpose of these studies was to determine whether large or total lesioning in the pre-B?tzC area of goats would eliminate phasic diaphragm activity and the eupneic breathing pattern. In awake goats that already had 29% bilateral destruction of neurokinin-1 receptor-expressing neurons in the pre-B?tzC area, bilateral ibotenic acid (10 microl, 50 mM) injection into the pre-B?tzC area resulted in a tachypneic hyperpnea that reached a maximum (132 +/- 10.1 breaths/min) approximately 30-90 min after bilateral injection. Thereafter, breathing frequency declined, central apneas resulted in arterial hypoxemia (arterial Po2 approximately 40 Torr) and hypercapnia (arterial Pco2 approximately 60 Torr), and, 11 +/- 3 min after the peak tachypnea, respiratory failure was followed by cardiac arrest in three airway-intact goats. However, after the peak tachypnea in four tracheostomized goats, mechanical ventilation was initiated to maintain arterial blood gases at control levels, during which there was no phasic diaphragm or abdominal muscle activity. When briefly removed from the ventilator (approximately 90 s), these goats became hypoxemic and hypercapnic. During this time, minimal, passive inspiratory flow resulted from phasic abdominal muscle activity. We estimate that 70% of the neurons within the pre-B?tzC area were lesioned in these goats. We conclude that, in the awake state, the pre-B?tzC is critical for generating a diaphragm, eupneic respiratory rhythm, and that, in the absence of the pre-B?tzC, spontaneous breathing reflects the activity of an expiratory rhythm generator.  相似文献   
9.
Abstract

Different modified PNA-DNA dimer-analogous synthons (I and II) were synthesized as phosphoramidites. These dimer units were assembled by a 5′-modified deoxythymidine and a modified PNA monomer. These synthons were used in the routine coupling procedure for oligonucleotides. Therefore no PNA coupling chemistry is necessary to synthesize PNA-DNA chimeric oligonucleotides. Various deoxyoligonucleotides were synthesized introducing the dimer blocks I and II at different positions in the sequences. Melting temperatures of the modified oligonucleotides with their complementary DNA analogues were determined.

Backbone modifications of oligonucleotides are required in the antisense strategy for protection against endonucleolytic cleavage in biological environment. Peptide nucleic acids (PNA fragments) are known to be nuclease resistant analogues, which show stable and discriminating hybridization. For this reason we prepared chimeric PNA-DNA oligomers by incorporation of two different modified PNA-DNA dimer blocks (Scheme A) into oligonucleotides. Melting temperatures of the modified oligonucleotides with their complementary DNA were determined.  相似文献   
10.
Potato virus Y (PVY) strains are transmitted by different aphid species in a non‐persistent, non‐circulative manner. Green peach aphid (GPA), Myzus persicae Sulzer, is the most efficient vector in laboratory studies, but potato aphid (PA), Macrosiphum euphorbiae Thomas (both Hemiptera: Aphididae, Macrosiphini), and bird cherry‐oat aphid (BCOA), Rhopalosiphum padi L. (Hemiptera: Aphididae, Aphidini), also contribute to PVY transmission. Studies were conducted with GPA, PA, and BCOA to assess PVY transmission efficiency for various isolates of the same strain. Treatments included three PVY strains (PVYO, PVYN:O, PVYNTN) and two isolates of each strain (Oz and NY090031 for PVYO; Alt and NY090004 for PVYN:O; N4 and NY090029 for PVYNTN), using each of three aphid species as well as a sham inoculation. Virus‐free tissue‐cultured plantlets of potato cv. Russet Burbank were used as virus source and recipient plants. Five weeks post inoculation, recipient plants were tested with quantitative DAS‐ELISA to assess infection percentage and virus titer. ELISA‐positive recipient plants were assayed with RT‐PCR to confirm presence of the expected strains. Transmission efficiency (percentage infection of plants) was highest for GPA, intermediate for BCOA, and lowest for PA. For all aphid species, transmission efficiency did not differ significantly between isolates within each strain. No correlations were found among source plant titer, infection percentage, and recipient plant titer. For both GPA and BCOA, isolates of PVYNTN were transmitted with greatest efficiency followed by isolates of PVYO and PVYN:O, which might help explain the increasing prevalence of necrotic strains in potato‐growing regions. Bird cherry‐oat aphid transmitted PVY with higher efficiency than previously reported, suggesting that this species is more important to PVY epidemiology than has been considered.  相似文献   
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