Surgical transplantation of sexually immature ovaries in rainbow trout (Oncorhynchus mykiss)

Transplantation of testes between isogenic rainbow trout males has been recently demonstrated. The objective of the present investigation was to determine if ovaries detached from the body wall and removed from the abdominal cavity would reestablish themselves when autografted to an ectopic site. In the first experiment, eleven sexually immature, female rainbow trout were laparotomized midventrally, and the right ovary was removed and transplanted to the abdominal cavity and positioned along the pyloric cecae on the right side. In the second experiment, the ovary was autografted in four animals as in experiment 1 or was transferred to and allografted in four other sexually immature female trout. The animals were examined three months following surgery. At the termination of experiment 1, the autografted ovaries were present in 73% of the animals; the transplanted ovaries were smaller in size than the intact control ovaries. Histological examination did not reveal any necrotic tissue in these transplanted gonads, and oocyte development was not different between the transplanted and the intact ovary within animal. Transplanted ovaries allografted from another female were not found. Taken together, these data support the conclusion that rainbow trout ovaries detached from the body wall can reestablish their blood supply and maintain ovarian development and that female trout appear to reject gonadal tissue from other individuals of their species.     

End-Point Variability Is Not Noise in Saccade Adaptation

When each of many saccades is made to overshoot its target, amplitude gradually decreases in a form of motor learning called saccade adaptation. Overshoot is induced experimentally by a secondary, backwards intrasaccadic target step (ISS) triggered by the primary saccade. Surprisingly, however, no study has compared the effectiveness of different sizes of ISS in driving adaptation by systematically varying ISS amplitude across different sessions. Additionally, very few studies have examined the feasibility of adaptation with relatively small ISSs. In order to best understand saccade adaptation at a fundamental level, we addressed these two points in an experiment using a range of small, fixed ISS values (from 0° to 1° after a 10° primary target step). We found that significant adaptation occurred across subjects with an ISS as small as 0.25°. Interestingly, though only adaptation in response to 0.25° ISSs appeared to be complete (the magnitude of change in saccade amplitude was comparable to size of the ISS), further analysis revealed that a comparable proportion of the ISS was compensated for across conditions. Finally, we found that ISS size alone was sufficient to explain the magnitude of adaptation we observed; additional factors did not significantly improve explanatory power. Overall, our findings suggest that current assumptions regarding the computation of saccadic error may need to be revisited.     

Dynamics of Circulating γδ T Cell Activity in an Immunocompetent Mouse Model of High-Grade Glioma

Human γδ T cells are potent effectors against glioma cell lines in vitro and in human/mouse xenograft models of glioblastoma, however, this effect has not been investigated in an immunocompetent mouse model. In this report, we established GL261 intracranial gliomas in syngeneic WT C57BL/6 mice and measured circulating γδ T cell count, phenotype, Vγ/Vδ repertoire, tumor histopathology, NKG2D ligands expression, and T cell invasion at day 10–12 post-injection and at end stage. Circulating γδ T cells transiently increased and upregulated Annexin V expression at post-tumor day 10–12 followed by a dramatic decline in γδ T cell count at end stage. T cell receptor repertoire showed no changes in Vγ1, Vγ4, Vγ7 or Vδ1 subsets from controls at post-tumor day 10–12 or at end stage except for an end-stage increase in the Vδ4 population. Approximately 12% of γδ T cells produced IFN-γ. IL-17 and IL-4 producing γδ T cells were not detected. Tumor progression was the same in TCRδ^-/- C57BL/6 mice as that observed in WT mice, suggesting that γδ T cells exerted neither a regulatory nor a sustainable cytotoxic effect on the tumor. WT mice that received an intracranial injection of γδ T cells 15m following tumor placement showed evidence of local tumor growth inhibition but this was insufficient to confer a survival advantage over untreated controls. Taken together, our findings suggest that an early nonspecific proliferation of γδ T cells followed by their depletion occurs in mice implanted with syngeneic GL261 gliomas. The mechanism by which γδ T cell expansion occurs remains a subject for further investigation of the mechanisms responsible for this immune response in the setting of high-grade glioma.     

Utility of reverse phase protein arrays: Applications to signalling pathways and human body arrays

Brief Funct     

Oxygen consumption in unfertilized salmonid eggs: an indicator of egg quality?

A negative correlation between oxygen consumption and fertility was observed in both steelhead and chinook salmon eggs. However, this relationship was attributed to bacterial growth. Elimination of samples with bacterial growth resulted in no significant relationship between the rate of oxygen consumption (VO2) and fertility. VO2 of unfertilized eggs of both steelhead and chinook salmon was measured over a storage period of up to 24 days (d). Despite declines in fertility during storage, VO2 did not significantly change throughout storage. The average respiration rate for steelhead eggs was 3.4 nmol O2 per egg per h, and was 4.3 nmol O2 per egg per h for chinook salmon eggs. Treatment of chinook salmon eggs with uncouplers of mitochondrial respiration, 2,4-dinitrophenol (2,4-DNP) and carbonyl cyanide 4-trifluoro-methoxyphenylhydrazone (FCCP), resulted in an increase in VO2 to 12.9 and 11.5 nmol O2 per egg per h, respectively. Treatment with the putative uncoupler, clove oil, resulted in no change in VO2, while KCN, an inhibitor of oxidative phosphorylation, reduced oxygen consumption to zero. Copper caused an increase in oxygen consumption, even in the absence of eggs, suggesting a need for caution in interpreting changes in respiration rates as a result of metal exposure. Thus, unfertilized salmonid eggs demonstrated submaximal VO2, which was not correlated with fertility.     

Adenosine triphosphate levels in steelhead (Oncorhynchus mykiss) eggs: an examination of turnover, localization and role

The dynamics of energy production and utilization in fish eggs before and shortly after fertilization may be critical for embryo survival. Therefore, the current study examined the turnover of adenosine triphosphate (ATP) as well as examined the possible role and localization of ATP in unfertilized steelhead (Oncorhynchus mykiss) eggs and early embryos. The mean ATP level in unfertilized steelhead eggs was 1.92+/-0.10 (mean+/-S.E.M., n=17) nmol ATP per egg. Exposure of the unfertilized egg to 10 degrees C water (water activation) and fertilization resulted in comparable and substantial decreases (approx. 20-50%) in egg ATP levels within 3 min. This suggests that the energy expended at fertilization is used in response to water activation rather than fertilization per se. Unfertilized eggs maintained in ovarian fluid for 9 days at 10 degrees C under air showed a progressive decline of fertility that reached zero after 6 days. In contrast, no significant changes were seen in ATP levels throughout this 9 days period. Thus, fertility does not positively correlate with egg ATP levels in stored eggs. In the unfertilized egg, the ATP stored in the yolk accounted for approximately 1.5% of the total egg ATP. After fertilization, the concentration of ATP in the yolk increased approximately seven-fold, with the yolk and blastoderm each now accounting for approximately 20% of the total remaining ATP. Finally, to estimate the changes in oxidative metabolism following fertilization, the cyanide (KCN)-sensitive decline in total ATP was determined for unfertilized eggs and 1 day embryos. In the presence of KCN, ATP levels declined to approximately 50% within 24 h in both unfertilized eggs as well as embryos; the rates of ATP decline were not different. Therefore, there was not a discernible increase in ATP generation by oxidative phosphorylation at the time of fertilization.     

Mesoporous MoO3–x Material as an Efficient Electrocatalyst for Hydrogen Evolution Reactions

A unique approach for the synthesis of nonstoichiometric, mesoporous molybdenum oxide (MoO_3–x) with nanosized crystalline walls by using a soft template (PEO‐b‐PS) synthesis method is introduced. The as‐synthesized mesoporous MoO_3–x is very active and stable (durability > 12 h) for the electrochemical hydrogen evolution reaction (HER) under both acidic and alkaline conditions. The intrinsic MoO₃ serves as an HER electrocatalyst without the assistance of carbon materials, noble metals, or MoS₂ materials. The results from transmission electron microscopy and N₂ sorption techniques show that the as‐synthesized mesoporous MoO_3–x has large accessible pores (20–40 nm), which are able to facilitate mass transport and charge transfer during HER. In terms of X‐ray diffraction, X‐ray photoelectron spectroscopy, temperature‐programmed oxidation, and diffusive reflectance UV–vis spectroscopy, the mesoporous MoO_3–x exhibits mixed oxidation states (Mo⁵⁺, Mo⁶⁺) and an oxygen‐deficient structure. The as‐synthesized MoO_3–x only requires a low overpotential (≈0.14 V) to achieve a 10 mA cm^?2 current density in 0.1 m KOH and the Tafel slope is as low as 56 mV dec^?1. Density functional theory calculations demonstrate a change of electronic structure and the possible reaction pathway of HER. Oxygen vacancies and mesoporosity serve as key factors for excellent performance.     

A reversible, hydrogen ion blockade of spontaneous oocyte maturation in the starfish: locus of action.

Starfish (Asterias forbesi) oocytes encased within their follicle cells mature spontaneously during a portion of the normal reproductive period when released from the ovary into seawater. A previous report has shown that oocytes isolated in acidic seawater do not mature spontaneously but retain the capacity to do so when returned to normal seawater. The object of this study was to determine the mechanism by which acidic pH reversibly blocks spontaneous oocyte maturation in isolated follicles. Incidence of spontaneous oocyte maturation in follicles isolated in acidic seawater decreased as pH decreased from 7 to 4. Oocytes in which spontaneous maturation was inhibited (ASW at pH 4.7 TO 5.4) underwent germinal vesicle breakdown with the addition of 1-methyladenine. Oocytes isolated in acidic seawater (pH 4 or 5) with intact follicle cells matured spontaneously when transferred immediately to normal seawater pH 8); after four hours, 60-65% of the follicles incubated in seawater at pH 5 matured spontaneously when returned to normal seawater as compared to less than 10% of the follicles maintained at pH 4. Inhibition of spontaneous maturation was not reversible in the absence of the follicle cells. Oocytes isolated in acidic seawater with their follicle cells did not spontaneously mature when transferred to calcium-free seawater at pH 8. The results obtained support the hypothesis that acidic seawater reversibly inhibits spontaneous oocyte maturation by interfering with the release of meiosis-inducing substance from the follicle cells.