Macronutrient Self-Selection Pattern in Rats under Different Lighting Conditions

The effect of constant darkness (DD) and constant light (LL) on the circadian pattern of macronutrient self-selection, daily food intake and body weight was analysed in rats using an automated computer system. No significant differences in energy intake were observed between groups as regards energy intake or macronutrient preferences. Fat and CHO intakes showed a negative correlation (p < 0.005 in LL and p < 0.0005 in DD and LD), while protein intake remained constant, which suggests the existence of separate regulation mechanisms governing the intake of protein and energy. Energetic requirements can be preponderantly covered by CHO or fat, depending on the preferences of the animal. Body weight measurements reflected no significant variations between groups at the end of the experiment. However, the circadian pattern of wheel-running activity and the intake of the three macronutrients measured in both constant lighting conditions varied with respect to that observed in LD. This was particularly true in the case of LL, when constant illumination exerted a decoupling effect on the rhythms. The results indicate that lighting conditions modulate the circadian pattern of wheel-running activity and macronutrient intake. However, changes in temporal organisation of food intake did not affect macronutrient preferences, daily energy intake, number of meals, feeding duration or body weight, suggesting the existence of a double, circadian and homeostatic, control of such variables.     

Variability of Microbiota under Diverse Conditions of Soil Moistening

According to data on the abundance of taxonomic, physiological, and ecotrophic microbial groups, analysis of the seasonal changes in their composition under conditions of artificial (irrigation) and natural (wet land formation) soil moistening was carried out. It was revealed with statistical reliability that the greatest response to changes caused by different soil moistening modes was observed in the numbers of aerobic cellulose-degrading microorganisms, denitrifiers, and fungi. An increase in erosion resistance of steppe soils during irrigation is explained by the combined effect of physicochemical and biological processes, and by higher numbers of algae, fungi, aerobic cellulose-degrading microorganisms, and oligonitrophiles, in particular.     

Hybrid Composite Coatings for Durable and Efficient Solar Hydrogen Generation under Diverse Operating Conditions

Safe and practical solar‐driven hydrogen generators must be capable of efficient and stable operation under diurnal cycling with full separation of gaseous H₂ and O₂ products. In this study, a novel architecture that fulfills all of these requirements is presented. The approach is inherently scalable and provides versatility for operation under diverse electrolyte and lighting conditions. The concept is validated using a 1 cm² triple‐junction photovoltaic cell with its illuminated photocathode protected by a composite coating comprising an organic encapsulant with an embedded catalytic support. The device is compatible with operation under conditions ranging from 1 m H₂SO₄ to 1 m KOH, enabling flexibility in selection of semiconductor, electrolyte, membrane, and catalyst. Stable operation at a solar‐to‐hydrogen conversion efficiency of >10% is demonstrated under continuous operation, as well as under diurnal light cycling for at least 4 d, with simulated sunlight. Operational characteristics are validated by extended time outdoor testing. A membrane ensures products are separated, with nonexplosive gas streams generated for both alkaline and acidic systems. Analysis of operational characteristics under different lighting conditions is enabled by comparison of a device model to experimental data.     

Melanopsin-Derived Visual Responses under Light Adapted Conditions in the Mouse dLGN

A direct projection from melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs) reaches the primary visual thalamus (dorsal lateral geniculate nucleus; dLGN). The significance of this melanopsin input to the visual system is only recently being investigated. One unresolved question is the degree to which neurons in the dLGN could use melanopsin to track dynamic changes in light intensity under light adapted conditions. Here we set out to address this question. We were able to present full field steps visible only to melanopsin by switching between rod-isoluminant ‘yellow’ and ‘blue’ lights in a mouse lacking cone function (Cnga3^-/-). In the retina these stimuli elicited melanopsin-like responses from a subset of ganglion cells. When presented to anaesthetised mice, we found that ~25-30% of visually responsive neurones in the contralateral dLGN responded to these melanopsin-isolating steps with small increases in firing rate. Such responses could be elicited even with fairly modest increases in effective irradiance (32% Michelson contrast for melanopsin). These melanopsin-driven responses were apparent at bright backgrounds (corresponding to twilight-daylight conditions), but their threshold irradiance was strongly dependent upon prior light exposure when stimuli were superimposed on a spectrally neutral ramping background light. While both onset and offset latencies were long for melanopsin-derived responses compared to those evoked by rods, there was great variability in these parameters with some cells responding to melanopsin steps in <1 s. These data indicate that a subset of dLGN units can employ melanopsin signals to detect modest changes in irradiance under photopic conditions.     

Selection for Genetic Variation Inducing Pro-Inflammatory Responses under Adverse Environmental Conditions in a Ghanaian Population

Background

Chronic inflammation is involved in the pathogenesis of chronic age-associated, degenerative diseases. Pro-inflammatory host responses that are deleterious later in life may originate from evolutionary selection for genetic variation mediating resistance to infectious diseases under adverse environmental conditions.

Methodology/Principal Findings

In the Upper-East region of Ghana where infection has remained the leading cause of death, we studied the effect on survival of genetic variations at the IL10 gene locus that have been associated with chronic diseases. Here we show that an IL10 haplotype that associated with a pro-inflammatory innate immune response, characterised by low IL-10 (p = 0.028) and high TNF-α levels (p = 1.39×10⁻³), was enriched among Ghanaian elders (p = 2.46×10⁻⁶). Furthermore, in an environment where the source of drinking water (wells/rivers vs. boreholes) influences mortality risks (HR 1.28, 95% CI [1.09–1.50]), we observed that carriers of the pro-inflammatory haplotype have a survival advantage when drinking from wells/rivers but a disadvantage when drinking from boreholes (p_interaction = 0.013). Resequencing the IL10 gene region did not uncover any additional common variants in the pro-inflammatory haplotype to those SNPs that were initially genotyped.

Conclusions/Significance

Altogether, these data lend strong arguments for the selection of pro-inflammatory host responses to overcome fatal infection and promote survival in adverse environments.     

Growth Responses to Sodium by Bryophyllum tubiflorum under Conditions Inducing Crassulacean Acid Metabolism

The dry weight yield of plants of Bryophyllum tubiflorum Harvey, a species with Crassulacean acid metabolism characteristics, increased significantly (P < 1%) in response to added sodium (0.1 milliequivalents per liter NaCl was supplied to the culture solution initially containing less than 0.08 microequivalents per liter of Na) when grown under short day (8 hours) conditions but not when grown under long day conditions (16 hours).     

中华水韭对不同营养条件的生理生态响应

采用水培法,研究了不同营养条件对中华水韭叶片生理生化特性和光合荧光特性的影响。结果显示:随着营养液中氮、磷浓度的升高,中华水韭叶片的生理生化特性除叶绿素含量呈下降的变化趋势外,可溶性糖、丙二醛、脯氨酸含量、过氧化氢酶活性(CAT)均呈上升趋势,而过氧化物酶活性(POD)则呈先上升后下降的趋势;同时叶片光合荧光特性中除非光化学猝灭系数(qN)呈上升的趋势外,PSⅡ的最大量子产量(Fv/Fm)、有效量子产量(Yield)、光化学猝灭系数(qP)、最大潜在相对电子传递速率(Pm)以及快速光响应曲线初始斜率(α)和半饱和光强(Ik)均呈下降的趋势。研究表明,随着水体氮、磷浓度的升高,中华水韭在中度营养条件下(N 0.4mg·L~(-1)、P0.04mg·L~(-1))耐受性较好,但在高营养条件下(N 1.2mg·L~(-1)、P 0.12mg·L~(-1))耐受性较差,其渗透调节能力和抗氧化能力上升,但光合作用能力下降,抑制了中华水韭的正常光合生理活动,进而影响其生长,推测水体富营养化可能是造成中华水韭濒危的重要原因之一。     

Different Sensitivity of Complement to Salmonella typhimurium Accounts for the Difference in Natural Resistance to Murine Typhoid between A/J and C57BL/6 Mice

The difference in natural resistance to Salmonella typhimurium between S. typhimurium-resistant A/J mice and S. typhimurium-susceptible C57BL/6 mice was analyzed. In both strains, the growth of S. typhimurium was controlled in the spleen until 48 hr of infection, while serum C3b levels were increased in A/J mice immediately after infection but not in C57BL/6 mice. Incubation of A/J mouse serum with S. typhimurium or its lipopolysaccharide (LPS) generated sufficient amounts of C3b, but that of C57BL/6 mouse serum with them did not. A/J macrophages had higher intracellular killing activity in vitro than did C57BL/6 cells against S. typhimurium pre-opsonized with each corresponding fresh serum. However, the cells from both mice exhibited a similar level of killing activity against S. typhimurium pre-opsonized with fresh A/J serum or rabbit complement. The resistance of C57BL/6 mice was significantly increased by opsonizing S. typhimurium with fresh A/J serum or rabbit complement before inoculation. The serum level of interferon-γ (IFN-γ) in A/J mice was 2.7 times as high as in C57BL/6 mice at 48 hr post-infection. Recombinant murine IFN-γ enhanced the intracellular killing activity of macrophages from both mice when S. typhimurium was pre-opsonized with fresh A/J serum but not with fresh C57BL/6 serum. These findings suggest that A/J macrophages exhibit maximal killing activity against A/J serum-opsonized S. typhimurium in vivo when the cells are activated with IFN-γ. Therefore, the rapid and sufficient activation of complement by Salmonella LPS may render A/J mice more resistant against murine typhoid.     

Influence of Vibration on Motor Responses in the Upper Arm Muscles under Stationary Conditions and during Voluntary and Evoked Arm Movements under Limb Unloading Conditions

Locomotion of mammals, including humans, is based on the rhythmic activity of spinal cord circuitries. The functioning of these circuitries depends on multimodal afferent information and on supraspinal influences from the motor cortex. Using the method of transcranial magnetic stimulation (TMS) of arm muscle areas in the motor cortex, we studied the motor evoked potentials (MEP) in the upper arm muscles in stationary conditions and during voluntary and vibration-evoked arm movements. The study included 13 healthy subjects under arm and leg unloading conditions. In the first series of experiments, with motionless limbs, the effect of vibration of left upper arm muscles on motor responses in these muscles was evaluated. In the second series of experiments, MEP were compared in the same muscles during voluntary and rhythmic movements generated by left arm m. triceps brachii vibration (the right arm was stationary). Motionless left arm vibration led to an increase in MEP values in both vibrated muscle and in most of the non-vibrated muscles. For most target muscles, MEP was greater with voluntary arm movements than with vibration-evoked movements. At the same time, a similar MEP modulation in the cycle of arm movements was observed in the same upper arm muscles during both types of arm movements. TMS of the motor cortex significantly potentiated arm movements generated by vibration, but its effect on voluntary movements was weaker. These results indicate significant differences in the degree of motor cortex involvement in voluntary and evoked arm movements. We suppose that evoked arm movements are largely due to spinal rather than central mechanisms of generation of rhythmic movements.     

Masking Responses to Light in Period Mutant Mice

Masking is an acute effect of an external signal on an overt rhythm and is distinct from the process of entrainment. In the current study, we investigated the phase dependence and molecular mechanisms regulating masking effects of light pulses on spontaneous locomotor activity in mice. The circadian genes, Period1 (Per1) and Per2, are necessary components of the timekeeping machinery and entrainment by light appears to involve the induction of the expression of Per1 and Per2 mRNAs in the suprachiasmatic nuclei (SCN). We assessed the roles of the Per genes in regulating masking by assessing the effects of light pulses on nocturnal locomotor activity in C57BL/6J Per mutant mice. We found that Per1^?/? and Per2^?/? mice had robust negative masking responses to light. In addition, the locomotor activity of Per1^?/?/Per2^?/? mice appeared to be rhythmic in the light-dark (LD) cycle, and the phase of activity onset was advanced (but varied among individual mice) relative to lights off. This rhythm persisted for 1 to 2 days in constant darkness in some Per1^?/?/Per2^?/? mice. Furthermore, Per1^?/?/Per2^?/? mice exhibited robust negative masking responses to light. Negative masking was phase dependent in wild-type mice such that maximal suppression was induced by light pulses at zeitgeber time 14 (ZT14) and gradually weaker suppression occurred during light pulses at ZT16 and ZT18. By measuring the phase shifts induced by the masking protocol (light pulses were administered to mice maintained in the LD cycle), we found that the phase responsiveness of Per mutant mice was altered compared to wild-types. Together, our data suggest that negative masking responses to light are robust in Per mutant mice and that the Per1^?/?/Per2^?/? SCN may be a light-driven, weak/damping oscillator. (Author correspondence: shin.yamazaki@vanderbilt.edu)     

Human Postural Responses to Vibratory Stimulation of Calf Muscles under Conditions of Visual Inversion

The authors studied postural responses to bilateral vibratory stimulation (70 Hz, 1 mm, 2 s) of the calf triceps proprioceptors or anterior tibial muscles. Anteroposterior body tilts evoked by vibration were recorded by stabilography. The authors compared the values of postural responses under various conditions of visual control, namely, with normal vision, eyes closed, right–left inversion of the visual space by prismatic spectacles, central vision, and diffuse light. Visual inversion influenced the subjects' proprioceptive postural responses. The amplitude of vibration-evoked shifts of the feet pressure center was minimal with eyes open and significantly increased with eyes closed and inverted vision. Postural responses with visual inversion were significantly stronger than with eyes closed. Since inversion spectacles enabled a subject to see only the central part of the visual field (20°), the reference point was the condition of central vision, i.e., spectacles with same visual angle and without prisms. Postural responses were significantly weaker under these conditions than with visual inversion and eyes closed. Visual field inversion by prismatic spectacles made it impossible to use visual information for stabilizing the human upright posture and, moreover, destabized it. True, this holds only for a randomized experimental protocol, which prevents adaptation to prisms.     

An Unconventional Copper Protein Required for Cytochrome c Oxidase Respiratory Function under Extreme Acidic Conditions

Very little is known about the processes used by acidophile organisms to preserve stability and function of respiratory pathways. Here, we reveal a potential strategy of these organisms for protecting and keeping functional key enzymes under extreme conditions. Using Acidithiobacillus ferrooxidans, we have identified a protein belonging to a new cupredoxin subfamily, AcoP, for “acidophile CcO partner,” which is required for the cytochrome c oxidase (CcO) function. We show that it is a multifunctional copper protein with at least two roles as follows: (i) as a chaperone-like protein involved in the protection of the Cu_A center of the CcO complex and (ii) as a linker between the periplasmic cytochrome c and the inner membrane cytochrome c oxidase. It could represent an interesting model for investigating the multifunctionality of proteins known to be crucial in pathways of energy metabolism.     

Light-Induced Adaptive Responses under Greenhouse and Controlled Conditions in the Fern Pteris cretica var. ouvrardii

The photosynthetic capabilities of the fern Pteris cretica var. ouvrardii were analysed by means of the light response curves of CO₂ exchange. In control growth conditions (greenhouse, low-light: 20–32 W m^?2); photosynthesis was shown to be saturated for low irradiance (20–25 W m^?2); the saturating photosynthetic rate, very low as compared to higher plants, was due to an extremely high intracellular resistance. When irradiance during the photosynthesis measurement was higher than 60–80 W m^?2, a constant decline of net CO₂ exchange as a function of time was observed. When irradiance during growth was enhanced, whether in greenhouse (20–250 W m^?2) or controlled (62 W m^?2) conditions, the first fronds that had developed in the new condition from the crosier stage exhibited decreased net maximal photosynthesis and a decreased efficiency in low light, but saturating irradiance was unmodified. However, the fronds whose entire differentiation (from meristem) occurred under these moderate irradiances (plants defoliated of all fronds and crosiers at the time of transfer), possessed more efficient photosynthetic characteristics than control plants. Pteris is able to grow under extreme shade conditions (4–8 W m^?2); light saturating photosynthesis and efficiency are higher under extreme shade than under control conditions. These adaptive characteristics indicate that Pteris is a well-adapted shade species.     

Light-Induced Adaptive Responses under Greenhouse and Controlled Conditions in the Fern Pteris cretica var. ouvrardii

The influence of different growth irradiance conditions on plant development and foliar features were assessed in a shade-adapted fern variety, Pteris cretica var. ouvrardii. A comparison of frond morphology, anatomy, chloroplast infrastructure and chlorophyll content of plants cultivated in both greenhouse and in controlled growth chambers under moderate light, low light (control) and extreme shade revealed pronounced phenotypic modifications. Moderate light induced decreased frond surfaces, thicker leaves, lower chlorophyll content per surface unit, and a markedly reduced density of intraplastidial membranes. In contrast, morphological responses to extreme shade included the formation of larger, thinner fronds, increased chlorophyll content; and a higher membrane density in chrloplasts. A dorsi-ventral distribution of starch-gorged chlroplasts (lower mesophyll cell layers) and essentially starch-free chloroplasts (upper cell layer) characterizes low-light and moderate light fronds, while homogenous starch-free chloroplasts are present in all cell layers of extreme shade fronds. The light-induced modifications are discussed as adaptive responses.     

The Phosphoenolpyruvate Carboxykinase of Mycobacterium Tuberculosis Induces Strong Cell-Mediated Immune Responses in Mice

Phosphoenolpyruvate carboxykinase (PEPCK) catalyzes guanosine or adenosine mononucleotide-dependent reversible conversion of oxaloacetate (OAA) and phosphoenolpyruvate (PEP). Mycobacterium (M) tuberculosis possesses a putative GTP-dependent PEPCK. To analyze the immune responses caused by PEPCK, the effects of PEPCK on the induction of CD4⁺ T cells and cytokines such as IFN-γ, IL-12 and TNF-α were evaluated in mice. It was found that the number of CD4⁺ T cells was increased in the PEPCK immunized mice although the change of the number of CD8⁺ T cells was not significant. The cytokines IFN-γ, IL-12 and TNF-α were increased significantly in the mice immunized with PEPCK than those of incomplete adjuvant. These characteristics were further demonstrated in the mice infected by pckA mutated BCG strain. The results indicate that PEPCK can effectively induce cell-mediated immune response by increasing activity of cytokines and PEPCK may be a promising new subunit vaccine candidate for tuberculosis.