Differential modulation of dopaminergic systems in the rat brain by dietary protein

Rats that consume a diet 50% rich in protein exhibit hyperactivity and hyperresponsiveness to nociceptive stimuli, in which facilitation of dopaminergic activity has been implicated. We studied the regional changes in the concentrations of dopamine (DA) and its metabolites, dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in the brains of rats that were maintained on high-protein (HP, 50% casein), normal-protein (NP, 20% casein), and low-protein (LP, 8% casein) diets for 36 weeks. Brain nuclei that represented different DAergic systems were punchdissected and analyzed using HPLC. In the substantia nigra, the striatum, and the dentate gyrus, DA concentrations decreased and increased, respectively, with a decrease and increase in dietary protein (p<0.05 compared to the NP diet). Similar trends in the effect of the HP diet were observed in the ventral tegmental area, amygdala, frontal cortex, subiculum, centromedial nucleus (CM) of the thalamus, and inferior colliculi (IC), although the differences in DA concentrations were not statistically significant. These brain areas also showed a pattern of decreased DA concentration in association with the LP diet, and the differences were statistically significant (p<0.05) in the CM and IC. DA concentrations in most regions of the midbrain and brainstem were not different between the diet groups, nor were consistent trends observed in those regions. Also, there were no consistent relationships between DOPAC/DA and HVA/DA ratios and dietary protein level. These data suggest that only discrete dopaminergic neuronal circuits in the rat forebrain were sensitive to changes in dietary protein level.     

Growth responses of tropical deciduous tree seedlings to contrasting light conditions

Summary The growth responses of seedlings of Amphipterygium adstringens, Caesalpinia eriostachys, and C. platyloba, species associated with undisturbed parts of the tropical deciduous forest in México, and Apoplanesia paniculata and Heliocarpus pallidus, two gap-requiring pioneer species, were determined under contrasting light conditions in a growth chamber experiment. The high (400 mol m^–2 s^–1) and low (80 mol m^–2 s^–1) light treatments correspond to the light available in a medium size gap and underneath the vegetation canopy in the deciduous forest during the rainy season, respectively. Following four destructive harvests the biomass production, relative growth rate, root/shoot ratio, specific leaf area, net assimilation rate, leaf area ratio and light dependency were determined for all species. In the high light treatment all species achieved higher relative growth rates and net assimilation rates than when growing at low light intensity. However, the two pioneer species showed the highest light dependency and were the species more affected by the low light treatment in biomass production. The two Caesalpinia species showed similar growth responses, but C. platyloba was the most shade tolerant species. Plastic adjustments in terms of the specific leaf area were more evident in the two pioneer species.     

Influence of vesicular-arbuscular mycorrhizae on biomass production by the cactus Pachycereus pecten-aboriginum

This study reports the effect of vesicular-arbuscular mycorrhizal (VAM) fungi on dry matter production by Pachycereus pecten-aboriginum (Engelm.) Britt & Rose, an arborescent cactus of arid and tropical dry forest in Mexico. Seedlings in the presence or absence of VAM fungi were grown in soil between two plates of glass (20 × 30 cm) for 8 months inside growth chambers (30/25° C, 13/11 h day/night and a light intensity of 400 mol m^-2 s^-1). VAM seedlings had significantly (P<0.01) higher dry matter production (0.418 versus 0.169 g), root/shoot ratios (0.26 versus 0.14) and specific root length (0.65 versus 1.41 mm mg^-1) than non-VAM seedlings, suggesting a more efficient exploitation of soil resources by the VAM cacti. The data point to a role for VAM fungi in the establishment, growth, water relations and nutrition of cacti in the arid tropics.     

Potential of somatic embryogenesis in Prunus avium immature zygotic embryos

For the purpose of developing somatic embryogenesis in Prunus avium L., immature zygotic embryos, collected from five donor trees and sorted into two size classes (C1: 2.5–3.5 and C2: 3.6–4.5 mm), received various experimental treatments. When cultured for 10 days on an inductive medium containing 18.1 M 2,4-dichlorophenoxyacetic acid (2,4-d) and 9.3 M kinetin, then transferred to fresh medium without growth regulators, 2.5% of the C1 class cotyledons expressed direct somatic embryogenesis. C2 class cotyledons were less responsive. The response was also influenced by the chosen donor tree. In a few cases, spontaneous germination occurred. The presence of a root meristem was clearly demonstrated by histological examination of longitudinal sections. The replacement of half the amount of 2,4-d, present in the inductive medium mentioned above, by the same quantity of naphthaleneacetic acid reduced the incidence of somatic embryogenesis. Conversely, a rhizogenic response was strongly enhanced. When submitted to an inductive medium containing indoleacetic acid and zeatin without any subcultures for 3 months, C1 class cotyledons were the most morphogenic and developed leaves and cotyledon-like structures.Abbreviations BA 6-benzyladenine - 2,4-d 2,4-dichlorophenoxyacetic acid - IAA indoleacetic acid - IBA indolebutyric acid - NAA -naphthaleneacetic acid     

Optimizing the Production of Antioxidant and Antibacterial Alkaloids from Macleaya cordata by Subcritical Water Extraction Technology

In this work, the subcritical water extraction technology was used to extract alkaloids from Macleaya cordata, and the effects of extraction temperature and time on its yield were investigated to find the best extraction conditions. Moreover, the antioxidant capacity and antibacterial activity of Macleaya cordata extract were studied. Furthermore, through the single-factor method, it was found that properly increasing the extraction temperature and prolonging the extraction time was conducive to increasing alkaloid yield. Still, a considerable amount of alkaloids might be decomposed by heat, resulting in a decrease in their yield. The results showed that the optimal extraction temperature of alkaloids from Macleaya cordata with subcritical water is 190 °C, the time is 45 min, and the corresponding maximum yield is 35.19±0.12 mg/g (sanguinarine equivalent in raw materials). In addition, the antioxidation and bacteriostasis abilities of subcritical water extract are better than those of traditional hot water extract, indicating that it is a feasible method to extract alkaloids from Macleaya cordata with subcritical water.     

Discriminating physiological from non-physiological interfaces in structures of protein complexes: A community-wide study

Reliably scoring and ranking candidate models of protein complexes and assigning their oligomeric state from the structure of the crystal lattice represent outstanding challenges. A community-wide effort was launched to tackle these challenges. The latest resources on protein complexes and interfaces were exploited to derive a benchmark dataset consisting of 1677 homodimer protein crystal structures, including a balanced mix of physiological and non-physiological complexes. The non-physiological complexes in the benchmark were selected to bury a similar or larger interface area than their physiological counterparts, making it more difficult for scoring functions to differentiate between them. Next, 252 functions for scoring protein-protein interfaces previously developed by 13 groups were collected and evaluated for their ability to discriminate between physiological and non-physiological complexes. A simple consensus score generated using the best performing score of each of the 13 groups, and a cross-validated Random Forest (RF) classifier were created. Both approaches showed excellent performance, with an area under the Receiver Operating Characteristic (ROC) curve of 0.93 and 0.94, respectively, outperforming individual scores developed by different groups. Additionally, AlphaFold2 engines recalled the physiological dimers with significantly higher accuracy than the non-physiological set, lending support to the reliability of our benchmark dataset annotations. Optimizing the combined power of interface scoring functions and evaluating it on challenging benchmark datasets appears to be a promising strategy.     

Influence of mineral nutrient availability on growth of tree seedlings from the tropical deciduous forest

The effects of different nutrient availabilities on growth and biomass partitioning in seedlings from the tropical deciduous forest in Mexico were compared. The tree species studied were Heliocarpus pallidus, a species associated with disturbed parts of the forest, and Caesalpinia eriotachys, Jacquinia pungens and Recchia mexicana, species from mature, undisturbed habitats. The tropical deciduous tree seedlings were grown in pure silica sand for 50 days inside growth chambers under four nutrient regimes; 5, 20, 100 and 200% Long Ashton nutrient solutions. Data showed contrasting responses among species to different nutrient availabilities. Except Jacquinia pungens, all species had increased growth and productivity as nutrient level increased from 5 to 100%; however, no significant differences in these parameters were detected between 100 and 200% in all species. Compared with mature forest species, pioneer species showed higher variations in biomass production, relative growth rate and net assimilation rate. In contrast to mature forest species, root/ shoot ratios in Heliocarpus pallidus were greater and thus showed higher biomass allocation to roots when nutrient supply was limited. This response suggests higher phenotypic plasticity in pioneer species. Species from mature parts of the forest (Caesalpinia eriostachys, Recchia mexicana) showed less dependency on nutrient supply than pioneer species. These responses appear to support observations from studies with temperate plants investigating growth responses to soil fertility.     

Biosynthesis and metabolic roles of cadystins (γ-EC)nG and their precursors in Datura innoxia

Metal-tolerant Datura innoxia cells synthesize large amounts of cadystin, [poly(-glutamylcysteinyl) glycines, (-EC)_nG, n=2–5], a class of metal-binding polypeptides, when exposed to Cd. These polypeptides have a high affinity for Cd (II) and certain other metal ions and are thought to play a role in metal tolerance in higher plants. Cells rapidly synthesize these metal-binding polypeptides when exposed to Cd and cellular concentrations of glutathione and cysteine, precursors for the synthesis of these compounds, are initially depleted then rapidly replenished. The time-frame of de novo polypeptide, glutathione and cysteine biosynthesis suggests that this pathway is, at least initially, regulated at the enzyme level. Significant amounts of Fe are associated with Cd: polypeptide complexes isolated from D. innoxia. Exposure of cultures to Cd results in an increased Fe accumulation by the cells. All the additional Fe found in the soluble portion of cell extracts is associated with the Cd: polypeptide complexes. The physiological significance of the synthesis of these polypeptides and their precursors and its relevance to Cd tolerance and metal homeostasis are discussed.     

Phytochemical analysis and toxicological evaluation of the ethanolic Leaves extract of Hypoestes rosea on the morphology and biochemical indices of the Kidneys of albino Wistar Rats

BackgroundHypoestes rosea (family: Acanthacea), has been harnessed and utilized for treatment of several ailments. However, there is the paucity of available data on nephrotoxicity associated with this herb. Here, we investigated the phytochemical profile and toxicological effect of H. rosea on Wistar Rats.MethodsTwenty rats (weight range: 75–100 g) were assigned into five study groups, viz; (a) control (without treatment) (b) treatment group 1, orally administered with 50 mg/kg (c) treatment group 2, orally administered with 100 mg/kg (d) treatment group 3, orally administered with 250 mg/kg, and (e) treatment group 4, orally administered with 300 mg/kg of H. rosea, respectively for 28 days of four rats per group. The rats were made unconscious by using oral administration of chloroform. Cardiac punctures were made, and blood samples collected into 10 ml labeled plain container, allowed to clot and spun to harvest serum for determination of sodium, potassium, chloride, bicarbonate, urea and creatinine using colorimetric, back-titrimetric, Urease-Berthelot and Jaffe’s reaction methods respectively. Kidneys of rats were harvested, weighed and immediately fixed in 10% neutral buffered formalin for histological analysis.ResultMean serum sodium (p = 0.049), potassium (p = 0.007), and urea (p < 0.001) levels were significantly higher among the treatment groups compared to controls. Histopathological findings of kidney sections revealed mild glomerular infiltration in treatment groups 2–4. Additionally, sclerosis was observed in groups 3–4. Phytochemical analysis of H. rosea revealed presence of alkaloids, flavonoids, saponins, tannins, terpenoids, steroids and reducing sugars.ConclusionFrom the findings in this study, H. rosea leaf extract causes significant damage to the kidneys of Wistar rats at higher doses. Of which, the damages were dose-dependent in direct proportionality manner. To better determine the safe dosage and ideal duration of consumption, there is the need for further studies on H. rosea.     

Multimodal biomarker discovery for active Onchocerca volvulus infection

The neglected tropical disease onchocerciasis, or river blindness, is caused by infection with the filarial nematode Onchocerca volvulus. Current estimates indicate that 17 million people are infected worldwide, the majority of them living in Africa. Today there are no non-invasive tests available that can detect ongoing infection, and that can be used for effective monitoring of elimination programs. In addition, to enable pharmacodynamic studies with novel macrofilaricide drug candidates, surrogate endpoints and efficacy biomarkers are needed but are non-existent. We describe the use of a multimodal untargeted mass spectrometry-based approach (metabolomics and lipidomics) to identify onchocerciasis-associated metabolites in urine and plasma, and of specific lipid features in plasma of infected individuals (O. volvulus infected cases: 68 individuals with palpable nodules; lymphatic filariasis cases: 8 individuals; non-endemic controls: 20 individuals). This work resulted in the identification of elevated concentrations of the plasma metabolites inosine and hypoxanthine as biomarkers for filarial infection, and of the urine metabolite cis-cinnamoylglycine (CCG) as biomarker for O. volvulus. During the targeted validation study, metabolite-specific cutoffs were determined (inosine: 34.2 ng/ml; hypoxanthine: 1380 ng/ml; CCG: 29.7 ng/ml) and sensitivity and specificity profiles were established. Subsequent evaluation of these biomarkers in a non-endemic population from a different geographical region invalidated the urine metabolite CCG as biomarker for O. volvulus. The plasma metabolites inosine and hypoxanthine were confirmed as biomarkers for filarial infection. With the availability of targeted LC-MS procedures, the full potential of these 2 biomarkers in macrofilaricide clinical trials, MDA efficacy surveys, and epidemiological transmission studies can be investigated.