Modulation of auxin signalling through DIAGETROPICA and ENTIRE differentially affects tomato plant growth via changes in photosynthetic and mitochondrial metabolism

Auxin modulates a range of plant developmental processes including embryogenesis, organogenesis, and shoot and root development. Recent studies have shown that plant hormones also strongly influence metabolic networks, which results in altered growth phenotypes. Modulating auxin signalling pathways may therefore provide an opportunity to alter crop performance. Here, we performed a detailed physiological and metabolic characterization of tomato (Solanum lycopersicum) mutants with either increased (entire) or reduced (diageotropica—dgt) auxin signalling to investigate the consequences of altered auxin signalling on photosynthesis, water use, and primary metabolism. We show that reduced auxin sensitivity in dgt led to anatomical and physiological modifications, including altered stomatal distribution along the leaf blade and reduced stomatal conductance, resulting in clear reductions in both photosynthesis and water loss in detached leaves. By contrast, plants with higher auxin sensitivity (entire) increased the photosynthetic capacity, as deduced by higher V_cmax and J_max coupled with reduced stomatal limitation. Remarkably, our results demonstrate that auxin‐sensitive mutants (dgt) are characterized by impairments in the usage of starch that led to lower growth, most likely associated with decreased respiration. Collectively, our findings suggest that mutations in different components of the auxin signalling pathway specifically modulate photosynthetic and respiratory processes.     

COVID-19 impact on the diagnosis of Inborn Errors of Metabolism: Data from a reference center in Brazil

The COVID-19 pandemic led to the reorganization of health care in several countries, including Brazil. Inborn Errors of Metabolism (IEM) are a group of rare and difficult to diagnose genetic diseases caused by pathogenic variants in genes that code for enzymes, cofactors, or structural proteins affecting different metabolic pathways. The aim of this study was to evaluate how COVID-19 affected the diagnosis of patients with IEM during the first year of the pandemic in Brazil comparing two distinct periods: from March 1^st, 2019 to February 29^th, 2020 (TIME A) and from March 1^st, 2020 to February 28^th, 2021 (TIME B), by the analysis of the number of tests and diagnoses performed in a Reference Center in South of Brazil. In the comparison TIME A with TIME B, we observe a reduction in the total number of tests performed (46%) and in the number of diagnoses (34%). In both periods analyzed, mucopolysaccharidoses (all subtypes combined) was the most frequent LD suspected and/or confirmed. Our data indicates a large reduction in the number of tests requested for the investigation of IEM and consequently a large reduction in the number of diagnoses caused by the COVID-19 pandemic leading to a significant underdiagnosis of IEM.     

Strength exercise suppresses STZ-induced spatial memory impairment and modulates BDNF/ERK-CAMKII/CREB signalling pathway in the hippocampus of mice

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that has generated scientific interest because of its prevalence in the population. Studies indicate that physical exercise promotes neuroplasticity and improves cognitive function in animal models and in human beings. The aim of the present study was to investigate the effects of strength exercise on the hippocampal protein contents and memory performance in mice subjected to a model of sporadic AD induced by streptozotocin (STZ). Swiss mice received two injections of STZ (3 mg/kg, intracerebroventricular). After 21 days, they began physical training using a ladde. Mice performed this protocol for 4 weeks. After the last exercise training session, mice performed the Morris Water Maze test. The samples of hippocampus were excised and used to determine protein contents of brain-derived neurotrophic factor (BDNF), extracellular signal-regulated kinase-Ca²⁺ (ERK), calmodulin-dependent protein kinase (CAMKII) and cAMP-response element-binding protein (CREB) signalling pathway. Strength exercise was effective against the decrease in the time spent and distance travelled in the target quadrant by STZ-injected mice. Strength exercise was also effective against the reduction of mature BDNF, tropomyosin receptor kinase B and neuronal nuclear antigen (NeuN) hippocampal protein levels in STZ mice. The decrease in the hippocampal ratio of pERK/ERK, pCAMKII/CAMKII and pCREB/CREB induced by STZ was reversed by strength exercise. Strength exercise decreased Bax/Bcl2 ratio in the hippocampus of STZ-injected mice. The present study demonstrates that strength exercise modulated the hippocampal BDNF/ERK-CAMKII/CREB signalling pathway and suppressed STZ-induced spatial memory impairment in mice.     

NTPDase and 5′-Nucleotidase Activities in Synaptosomes of Hippocampus and Serum of Rats Subjected to Homocysteine Administration

Patients with homocystinuria, an inborn error of metabolism, present neurological dysfunction and commonly experience frequent thromboembolic complications. The nucleoside triphosphate diphosphohydrolase (NTPDase) and 5'-nucleotidase enzymes regulate the nucleotide/nucleoside ratio in the central nervous system and in the circulation and are thought to be involved in these events. Thus, the current study investigated the effect of homocysteine administration on NTPDase and 5'-nucleotidase activities, in the synaptosomal fraction of rat hippocampus, and on nucleotidase activities in rat serum. Twenty-nine-day-old Wistar rats were divided in two groups: group I (control), animals received 0.9% saline; group II (homocysteine-treated), animals received one single subcutaneous injection of homocysteine (0.6 micromol/g). Rats were killed 1 h after the injection. NTPDase and 5'-nucleotidase activities from brain and serum were significantly increased in the homocysteine-treated group. Results show that, in hippocampus, ATP and ADP hydrolysis increased by 20.5% and 20%, respectively, and AMP hydrolysis increased by 48%, when compared to controls. In serum, ATP and ADP hydrolysis increased 136% and 107%, respectively, and AMP hydrolysis increased 95%, in comparison to controls. The current data strongly indicate that in vivo homocysteine administration alters the activities of the enzymes involved in nucleotide hydrolysis, both in the central nervous system and in the serum of adult rats.     

Effect of DHEA Glutamate Release from Synaptosomes of Rats at Different Ages

Dehydroepiandrosterone (DHEA) exerts multiple effects in the central nervous system. Most of them seem to be mediated through their nongenomic actions on neurotransmitter receptors, and these actions occur within seconds or milliseconds. DHEA increases neuronal excitability, enhances neuronal plasticity, and has neuroprotective properties. By investigating glutamate release from synaptosomes of rats at different ages (from 17 days to 12 months), we observed that (i) there is an increase in basal and K(+)-stimulated L-[3H] glutamate release in rats at 12 months old, when compared to other ages; and (ii) there is an inhibitory effect of DHEA on basal L-[3H] glutamate release in 12 months old. This inhibitory effect of DHEA could be related to its reported protective role against excitotoxicity caused by overstimulation of the glutamatergic system and ageing.     

Cytoskeleton of human mononuclear cells as a possible peripheral marker for phenylalanine neurotoxicity in PKU

In this work we tested human mononuclear cells as a peripheral marker to study neurotoxicity of phenylalanine (Phe). Slices of cerebral cortex of rats or human mononuclear cells were incubated with different concentrations of Phe and/or Ala in the presence of ³²P-orthophosphate, the cytoskeletal fraction was extracted, and the radioactivity incorporated into intermediate filament proteins was measured. Our results show that 2 mM Phe as well as 1 mM Ala are effective in increasing the ³²P in vitro incorporation into IFs in both tissues. When cerebral cortex slices or mononuclear cells were incubated with different concentrations of Phe and/or Ala, the effects on the ³²P in vitro incorporation into IF proteins was compatible with an antagonistic mechanism of action of the two amino acids on the enzymes of the phosphorylating system. In addition, these blood cells may be a possible peripheral marker to study neurotoxicity of Phe in patients with PKU.     

Outlook on sponge reproduction science in the last ten years: are we far from where we should be?

To comprehend the state of the art of sponge reproduction science (SRS), we quantified and analyzed the trends in SRS in the last decade, aiming to answer three questions: (i) Were there fewer SRS works presented during the last sponge conference? (ii) Did the number of SRS publications decline in the last decade? (iii) Does the number of abstracts at sponge conferences influence overall SRS publications? In addition, we checked whether the SRS community has answered Ereskovsky’s ‘five important questions’, enabling us to advance SRS enough to be considered as a fourth period of this scientific field. We found that SRS was less represented at the last sponge conference, despite an increase in the number of publications during the last decade. Moreover, the number of abstracts presented at sponge conferences contributed to a small portion (25%) of the published works in this area during the last decade. In addition, we found that two of the five Ereskovsky’s questions are still mostly not answered. Thus, we conclude that SRS is healthy and advancing steadily, especially in some subareas (e.g. developmental biology and life history). There are still much to advance, but this is still a strong field of biological science research.     

Occurrence and correlations of nematodes,Fusarium oxysporum and edaphic factors on banana plantations

Problems caused by nematodes and Fusarium wilt (Panama disease) on banana plantations are responsible for yield losses and are limiting to its cultivation. In the state of Goias, there is little information about the nematode occurence on this crop, and its relation with the incidence of Fusarium oxysporum f.sp. cubense (Foc). This research had the purpose to identify the occurrence of plant‐parasitic nematodes on banana plantations and to verify its correlation with the Fusarium wilt and with the soil attributes (pH, texture, nutrients). Twelve banana orchards in the state of Goias were sampled in the municipalities of Anapolis, Caiaponia, Goiatuba, Itaguaru, Itumbiara (two areas), Jatai, Morrinhos, Ouro Verde, Palestina, Taquaral and Uruana. All sampled areas, except Morrinhos, revealed contamination with Foc, and all areas had different genera of nematodes either in the soil or in the roots samples. Meloidogyne sp., Helicotylenchus sp. and Rotylenchus sp. were the main genera of plant‐parasitic nematodes found in the samples, with Meloidogyne sp. and Rotylenchus sp. being the most dominant and abundant genera. The presence of Pratylenchus sp. increases the population levels of F. oxysporum. Helicotylenchus sp. is highly correlated with high concentrations of Mn. High population density of Meloidogyne sp. was found in irrigated areas with low concentrations of P, Ca, Mg and soil pH.