We investigated changes in burrow architecture and fractal dimension across seasons and between the sexes in the solitary East African root rat Tachyoryctes splendens over an entire calendar year. ...The basic burrow system comprised a main tunnel reticulating into foraging tunnels, a nest consisting of food store chamber, latrine and sleeping area, and a bolt hole. Main tunnel length was strongly affected by sex, and contrary to expectations, it was longer for females than for males (during both the dry and the wet seasons). The number and the length of foraging tunnels were affected by both sex and season, with females' burrows having more foraging tunnels than males in both the dry and the wet seasons. Females also had burrows with higher fractal dimension than males, while fractal dimension increased with burrow length for both sexes. We suggest that unlike the solitary bathyergid mole‐rats, male T. splendens do not construct larger burrows than females in the search for mates, but rather females have larger burrows with more foraging tunnels resulting from the increased need for provisioning of their young.
Tyrosinase Stabilization by Tyrp1 (the brown Locus Protein) Kobayashi, Takeshi; Imokawa, Genji; Bennett, Dorothy C. ...
Journal of biological chemistry/The Journal of biological chemistry,
11/1998, Letnik:
273, Številka:
48
Journal Article
Recenzirano
Odprti dostop
Mammalian melanogenesis is regulated directly or indirectly by over 85 distinct loci. TheTyr/albino locus, in which mutations cause a lack of pigmentation, encodes tyrosinase (Tyr), the critical and ...rate-limiting melanogenic enzyme. Other melanogenic enzymes include Tyrp1 (or TRP1) and 3,4-dihydroxyphenylalanine-chrome tautomerase (Dct or TRP2) encoded at the Tyrp1/brown and Dct/slaty loci, respectively. Murine Tyrp1 can oxidize 5,6-dihydroxyindole-2-carboxylic acid (DHICA) produced by Dct, but mutations in Tyrp1 also affect the catalytic functions of Tyr. All three enzymes are membrane-bound melanosomal proteins with similar structural features and are thought to interact within and stabilize a melanogenic complex. We have now further investigated the effect of aTyrp1b mutation on Tyr stability. Pulse/chase labeling experiments show that Tyr is degraded more quickly in Tyrp1b mutant melanocytes than in melanocytes wild type at that locus. This reduced stability of Tyr can be partly rescued by infection with the wild type Tyrp1 gene, and this is accompanied by phenotypic rescue of infected melanocytes. In sum, these results suggest that, in addition to its catalytic function in oxidizing DHICA, Tyrp1 may play an important role in stabilizing Tyr, a second potential role in the regulation of melanin formation.
Using a data sample collected with the BESIII detector operating at the BEPCII storage ring, we observe a new neutral state Z_{c}(3900)^{0} with a significance of 10.4σ. The mass and width are ...measured to be 3894.8±2.3±3.2 MeV/c^{2} and 29.6±8.2±8.2 MeV, respectively, where the first error is statistical and the second systematic. The Born cross section for e^{+}e^{-}→π^{0}π^{0}J/ψ and the fraction of it attributable to π^{0}Z_{c}(3900)^{0}→π^{0}π^{0}J/ψ in the range E_{c.m.}=4.19-4.42 GeV are also determined. We interpret this state as the neutral partner of the four-quark candidate Z_{c}(3900)^{±}.
To compare antibody responses and side-effects of aerosolized and injected measles vaccines after revaccination of children enrolling in elementary schools.
Vaccines for measles (Edmonston-Zagreb) or ...measles-rubella (Edmonston-Zagreb with RA27/3) were given by aerosol or injection to four groups of children. An additional group received Schwarz measles vaccine by injection. These five groups received vaccines in usual standard titre doses. A sixth group received only 1000 plaque-forming units of Edmonston-Zagreb vaccine by aerosol. The groups were randomized by school. Concentrations of neutralizing antibodies were determined in blood specimens taken at baseline and four months after vaccination from randomized subgroups (n = 28-31) of children in each group.
After baseline antibody titres were controlled for, the frequencies of fourfold or greater increases in neutralizing antibodies did not differ significantly between the three groups that received vaccine by aerosol (range 52%-64%), but they were significantly higher than those for the three groups that received injected vaccine (range 4%-23%). Mean increases in titres and post-vaccination geometric mean titres paralleled these findings. Fewer side-effects were noted after aerosol than injection administration of vaccine.
Immunogenicity of measles vaccine when administered by aerosol is superior to that when the vaccine is given by injection. This advantage persists with aerosolized doses less than or equal to one-fifth of usual injected doses. The efficacy and cost-effectiveness of measles vaccination by aerosol should be further evaluated in mass campaigns.
Despite increasing research effort and conservation focus on sharks, small species of little commercial value are often overlooked, although they make a considerable contribution to global diversity. ...The poorly known Colclough's shark, Brachaelurus colcloughi, is naturally rare to uncommon and is encountered only irregularly. Collating all known records (n=50), we review the species' geographic and bathymetric distribution, habitat, reproductive biology and diet. All but four B. colcloughi records are from within a core distribution of <2° latitude on the Australian east coast. Bathymetric distribution is from less than 4 to 217m depth, with all but three records from less than 100m depth. The species shelters on rocky reefs during the day and is thought to forage nocturnally around reefs and adjacent substrates. B. colcloughi is viviparous, with litter sizes of 6-7. Mature males and females have been observed from 61.0- and 54.5-cm total length, respectively. Gravid females have been collected in austral winter months. Dietary analysis indicates a predominantly piscivorous diet. Our results are placed in the context of existing threats and future research and management directions, demonstrating that shark species with low abundances and restricted ranges, such as B. colcloughi, require a suite of management arrangements to ensure long-term population viability.
Aging, often considered a result of random cellular damage, can be accurately estimated using DNA methylation profiles, the foundation of pan-tissue epigenetic clocks. Here, we demonstrate the ...development of universal pan-mammalian clocks, using 11,754 methylation arrays from our Mammalian Methylation Consortium, which encompass 59 tissue types across 185 mammalian species. These predictive models estimate mammalian tissue age with high accuracy (r > 0.96). Age deviations correlate with human mortality risk, mouse somatotropic axis mutations and caloric restriction. We identified specific cytosines with methylation levels that change with age across numerous species. These sites, highly enriched in polycomb repressive complex 2-binding locations, are near genes implicated in mammalian development, cancer, obesity and longevity. Our findings offer new evidence suggesting that aging is evolutionarily conserved and intertwined with developmental processes across all mammals.
Determine the mean post-menstrual age when preterm infants attain independent oral feeding skills and whether gestational age, common neonatal morbidities, gender, race, delivery route, or birth year ...affects this reflex.
A retrospective chart review of 2700 preterm infants, born before 37 weeks gestational age admitted to a level III NICU between January 1978 and July 2013, to determine the post-menstrual age when independent oral feedings occur.
Mean post-menstrual age at achievement of independent oral feeding was 36 + 4/7 weeks ± 14 days. Gestational age under 29 weeks correlated with delayed post-menstrual age at achievement of independent oral feeding at 37 + 3/7 weeks versus 36 + 1/7 weeks for gestational age 29-33 weeks and 36 + 3/7 weeks for late preterm infants (p < 0.0001). Preterm infants with certain morbidities experienced a delay in independent oral feeding: necrotizing enterocolitis at 38 + 6/7 weeks (p < 0.0001), bronchopulmonary dysplasia at 38 + 1/7 weeks (p < 0.0001), severe intraventricular hemorrhage at 37 + 6/7 weeks (p < 0.001). Preterm infants born before the year 2000 achieved independent oral feeding two days later than preterm infants born since the year 2000 (p < 0.0001). Preterm infants delivered vaginally achieved independent oral feeding three days sooner than infants delivered via c-section (p < 0.0001). Female infants orally fed one day sooner than male preterm infants (p = 0.0008).
Preterm infants achieve independent oral feeding at 36 + 4/7 weeks. Factors negatively influencing when the preterm infant will achieve independent oral feeding include gestational age under 29 weeks and major morbidities, whereas vaginal delivery and ongoing advances in neonatal care may accelerate the transition to independent oral feeding.
Warfarin is the most common oral anticoagulant used for chronic anticoagulation therapy. Even without any antecedent trauma overanticoagulation can result in intracranial hemorrhage. The triad of ...anticoagulation with warfarin, age greater than 65 years, and traumatic head injury frequently produces a lethal brain hemorrhage. A retrospective review of more than 2000 patients admitted to the Trauma Service between September 1998 and May 2000 produced 278 patients with head injury and CT-documented intracranial hemorrhage. Of these patients 21 were admitted with an elevated prothrombin time (FT) due to anticoagulation with warfarin. Eighteen patients (86%) were above the age of 70. The most common indications for anticoagulation were atrial fibrillation (71%), deep venous thrombosis (19%), aortic valve replacement (9%), and ischemic cerebral infarcts (9%). Fourteen injuries were the result of a fall, one resulted from a gunshot wound, and one resulted from an assault. The remaining five patients were excluded as their history, workup, and evaluation by neurosurgery suggested a spontaneous bleed leading to fall rather than a fall causing a traumatic bleed. The average Glasgow Coma Score on admission was 11. The average PT and International Normalized Ratio (INR) on admission were 19.2 and 2.99 respectively. Eight of the 16 patients analyzed died. The risk of intracranial hemorrhage with relatively minor head injury is increased dramatically in the anticoagulated patient. A mortality rate of 50 per cent far exceeds the mortality rate in patients with similar head injuries who are not anticoagulated. In addition the risk/benefit equation of anticoagulation for the elderly is more complex and differs from that for younger patients. Perhaps more frequent and judicious monitoring of prothrombin time levels with lower therapeutic ranges (INR 1.5–2) is necessary.
Using a low background data sample of 9.7×10^{5} J/ψ→γη^{'}, η^{'}→γπ^{+}π^{-} events, which are 2 orders of magnitude larger than those from the previous experiments, recorded with the BESIII ...detector at BEPCII, the decay dynamics of η^{'}→γπ^{+}π^{-} are studied with both model-dependent and model-independent approaches. The contributions of ω and the ρ(770)-ω interference are observed for the first time in the decays η^{'}→γπ^{+}π^{-} in both approaches. Additionally, a contribution from the box anomaly or the ρ(1450) resonance is required in the model-dependent approach, while the process specific part of the decay amplitude is determined in the model-independent approach.
The East African root rat Tachyoryctes splendens (Rüppell, 1835) is a solitary subterranean rodent mole. The present study investigated breeding patterns in both sexes of T. splendens from data ...collected at monthly intervals over an entire calendar year. The study focused on the analyses from post‐mortem examination of male and female East African root rats to assess the presence of foetuses, gonadal histology, reproductive tract morphometrics, measurement of gonadal steroids (plasma progesterone and oestradiol‐17β in females and testosterone in males) and field observations (i.e. the presence of infants, juveniles, subadults and lactating females). The objective of this study was to assess if the reproductive biology of root rats reflected the bimodal pattern of rainfall that is characteristic of East Africa. Rainfall has been suggested to trigger breeding in many subterranean rodents and as a consequence, this study aimed to assess the relationship between rainfall and reproductive characteristics of T. splendens. Peaks in mean gonadal mass, increases in concentration of reproductive hormones and the presence of graafian follicles and corpora lutea in the ovaries of females, and testes mass, seminiferous tubule diameter and testosterone titre mirrored the annual peaks of precipitation at the study area. Together with field observations of the temporal occurrence of pregnancies, infants, juveniles and subadults, the data show that T. spendens cues its breeding with the patterns of rainfall, such that offspring are born in the latter half of each rainy season, from April to July and November to December.
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