Sporoderm ultrastructure and development in Aristolochia manshuriensis Komarov (Aristolochiaceae)

Pollen ontogeny and sporoderm development in Aristolochia manshuriensis were studied for elaboration of the inaperturete pollen ontogeny in Aristolochia. Despite the formation of apertures in the tetrad period, the sporoderm in A. manshuriensis becomes inaperturate at the end of the free microspore period. A similar immature exine is also detected in A. macrophylla. Variants of aperture formation in the tetrad period in A. manshuriensis or formation of a polar aperture in the free microspore period in A. clematitis are associated with types of microsporogenesis. The ectexine and endexine in A. manshuriensis are formed over a longer time and reached much greater thickness than those in A. clematitis. The endexine and intine in A. manshuriensis do not reach a mature state, similar to A. clematitis. The exine of A. manshuriensis cracks, releasing a pollen tube enveloped by the intine. This fact does not hinder the functioning of the male gametophyte of A. manshuriensis.     

Glutamic acid decarboxylase gene disruption reveals signalling pathway(s) governing complex morphogenic and metabolic events in Trichoderma atroviride

Glutamate decarboxylase (GAD) catalyses decarboxylation of glutamate to gamma-aminobutyrate (GABA) in a metabolic pathway connected to citrate cycle and known as GABA shunt. The gene (gad) was disrupted in Trichoderma atroviride CCM F-534 and viable mutants were characterized. Two of them were found to arise by homologous recombination and were devoid of both GAD activity and GABA. Mutants grew slower as compared to the wild type (F534). In the submerged culture, mutants developed less CO₂ and consumed less O₂ than the F534 without changing their respiratory quotients. Hyphae of mutants were more ramified than those of F534. Their ramification, in contrast to F534, was not increased by cyclosporin A, a drug causing hyphae ramification of several fungi and which is a calcineurin/cyclophilin inhibitor, or by FK506. Rapamycin, which is a cyclophilin but not calcineurin inhibitor, had a different effect on hyphae ramification in F534 and mutants. To examine the presence of GABA receptors in the fungus the effect of mammalian GABA-receptor modulators, such as bicuculline, gabapentin or carbamazepine on fungal morphology were investigated. Conidia of mutants germinated in a multipolar manner more frequently (up to 80 %) than those of F534. This trait was modified with cyclosporine A, FK506 and GABA receptor modulators in a different manner. Transport of chlorides, an intimate feature of GABA-regulated receptors/channels in animal cells, was measured in vegetative mycelia by means ³⁶Cl^? uptake. It was significantly reduced in gad mutants. The results suggest that T. atroviride possesses a signalling pathway that involves GABA, putative GABA receptor(s), calcineurin, target of rapamycin and chloride transporter(s) to regulate physiological functions.     

The citric acid production from raw glycerol by Yarrowia lipolytica yeast and its regulation

The optimal cultivation conditions ensuring the maximal rate of citric acid (CA) biosynthesis by glycerol-grown mutant Yarrowia lipolytica NG40/UV7 were found to be as follows: growth limitation by inorganic nutrients (nitrogen, phosphorus, or sulfur), 28 °C, pH 5.0, dissolved oxygen concentration (pO₂) of 50 % (of air saturation), and pulsed addition of glycerol from 20 to 80 g L^?1 depending on the rate of medium titration. Under optimal conditions of fed-batch cultivation, in the medium with pure glycerol, strain Y. lipolytica NG40/UV7 produced 115 g L^?1 of CA with the mass yield coefficient of 0.64 g g^?1 and isocitric acid (ICA) amounted to 4.6 g L^?1; in the medium with raw glycerol, CA production was 112 g L^?1 with the mass yield coefficient of 0.90 g g^?1 and ICA amounted to 5.3 g L^?1. Based on the activities of enzymes involved in the initial stages of raw glycerol assimilation, the tricarboxylic acid cycle and the glyoxylate cycle, the mechanism of increased CA yield from glycerol-containing substrates in Y. lipolytica yeast was explained.     

Cerebrospinal Fluid and Plasma Oxidative Stress Biomarkers in Different Clinical Phenotypes of Neuroinflammatory Acute Attacks. Conceptual Accession: From Fundamental to Clinic

Oxidative stress is revealed as the main contributor in the pathophysiology of neuroinflammation. Analyzing plasma and cerebrospinal fluid (CSF) of patients with different clinical phenotypes of neuroinflammation, defined as clinically isolated syndrome (CIS), and those defined as relapsing remitting multiples sclerosis (RRMS), we tested peripheral and CNS oxidative stress intensity in these neuroinflammatory acute attacks. All obtained values changes were assessed regarding clinical and radiological features of CNS inflammation. The obtained results revealed an increase in malondialdehyde levels in plasma and CSF in CIS and RRMS patients compared to control values (p < 0.05). The obtained values were most prevailed in both study group, CIS and RRMS, in patients with severe clinical presentation (p < 0.05). Measured activities of catalase and total superoxide dismutase were higher in CIS and RRMS patients in plasma compared to control values (p < 0.05), parallel with an increased catalase activity and decrease in superoxide dismutase activity in CSF regarding values obtained in control group (p < 0.05). The positive correlations regarding clinical score were obtained for all tested biomarkers (p < 0.01). Although the positive correlations were observed in MDA levels in plasma and CSF, for both study patients, and their radiological findings (p < 0.01), and a negative correlation in plasma SOD activity and CIS patients’ radiological findings (p < 0.01), no other similar correlations were obtained. These findings might be useful in providing the earliest antioxidative treatment in neuroinflammation aimed to preserve total and CNS antioxidative capacity parallel with delaying irreversible, later neurological disabilities.     

Chronic hypoxia leads to a glycolytic phenotype and suppressed HIF-2 signaling in PC12 cells

Background

Along with other regulators of cell metabolism, hypoxia-inducible factors HIF-1 and HIF-2 differentially regulate cell adaptation to hypoxia. Switches in HIF-1/HIF-2 signaling in chronic hypoxia have not been fully investigated.

Methods

Proliferation, viability, apoptosis, neuronal and bioenergetic markers, mitochondrial function, respiration, glycolysis, HIF signalling, responses to O₂ and glucose deprivation (OGD) were examined using tumor PC12 and SH-SY5Y cells continuously grown at 3% O₂.

Results

Hypoxic PC12 cells (H-cells) exhibit reduced proliferation and histone H4 acetylation, NGF-independent differentiation, activation of AMPK, inhibition of Akt, altered mitochondria and response to NGF. Cellular cytochrome c is increased with no effect on apoptosis. Reduction in respiration has minor effect on cellular ATP which is maintained through activated uptake (GLUT1) and utilization (HK2, PFK2) of glucose. H-cells exhibit resistance to OGD linked to increased glycogen stores. HIF-2alpha protein is decreased without changes in mRNA. Unlike HIF-1alpha, HIF-2alpha is not stabilized pharmacologically or by O₂ deprivation. Capacity for HIF-2alpha stabilization is partly restored when H-cells are cultured at normoxia. In low-respiring SH-SY5Y cells cultured under the same conditions HIF-2alpha stabilization and energy budget are not affected.

Conclusions

In chronically hypoxic PC12 cells glycolytic energy budget, increased energy preservation and low susceptibility to OGD are observed. HIF-2alpha no longer orchestrates adaptive responses to anoxia.

General significance

Demonstrated switch in HIF-1/HIF-2 signaling upon chronic hypoxia can facilitate cell survival in energy crisis, by regulating balance between energy saving and decrease in proliferation, on one hand and active cell growth and tumor expansion, on the other.     

Sources and donors of resistance to wheat spot blotch caused by Bipolaris sorokiniana Shoem. (Cochliobolus sativus Drechs. ex Dastur)

The resistance of wheat lines and cultivars from the Institute of Crop Breeding (Harbin, China) and synthetic, hexaploid wheat lines derived from T. durum and T. tauschii (CIMMYT) were screened for resistance to spot blotch Bipolaris sorokiniana Shoem. using field and laboratory tests. The highly and moderately resistant wheat samples were determined. The satisfactory coincidence of data obtained from evaluation of type reaction of seedlings and disease severity in adult plant stage was demonstrated. The genetics of resistance in Chinese lines Long 98-4554, Long 98-4546, Long mai 24, Long mai 23 and Canadian line 181-5 was studied using hybridological analysis. The resistance in these lines was inherited as quantitative traits and was conditioned by a few (one or two) genes. The absence of susceptible plants in F₂ in crosses of resistant lines Long 98-4554, Long 98-4546, Long mai 24 and 181-5 can testify to the presence of a common gene of resistance. Our data reveals the poor genetic diversity for spot blotch resistance in studying wheat genotypes.     

Lipids in the daubed shanny (Teleostei: Leptoclinus maculatus) in Svalbard waters

The daubed shanny, Leptoclinus maculatus, is a common fish species in Arctic and North Atlantic waters and has an important role in high-latitude ecosystems as a link between lower trophic levels and many fish, marine mammal and seabird species. Its biology and ecology have, however, remained largely unstudied. The primary aim of this study was to increase the knowledge about the daubed shanny by analysing total lipids, lipid-classes and the fatty acid composition of liver, muscle and female gonads in adults from the high Arctic archipelago of Svalbard. In female gonads, the triacylglycerols and wax esters in addition to cholesterol esters were dominant among the stored lipids. Triacylglycerols dominated in the liver, whereas structural lipids, such as phospholipids and cholesterols, were the most important lipids in muscles. Phosphatidylcholine and phosphatidylethanolamine were major phospholipids in all organs studied. The fatty acid spectrum of the investigated organs was characterized by a high amount of monounsaturated fatty acids, particularly in the liver. Polyunsaturated fatty acids, particularly 22:6(n-3) and 20:4(n-6), were prevalent in muscle tissues. The lipid and fatty acid spectra in the organs during this period of life are tightly connected with the activation of the liver metabolism and the storage of lipids in the developed female gonads. Lipid accumulation and distribution in gonads are transferred to optimal development of embryos and larvae in Arctic waters.     

The different morphs of Undaria pinnatifida (Phaeophyceae, Laminariales) in Peter the Great Bay (Sea of Japan) are phenotypic variants: direct evidence

Previous study elicited three morphologically distinct forms of Undaria pinnatifida in Peter the Great Bay (Sea of Japan), which were represented by one or more populations. It was supposed that their specific morphology is plastic response to the local environment. In the present study, we used molecular data in order to examine directly the degree of genetic similarity between these morphs. We performed amplified fragment length polymorphism and microsatellite analyses. In addition, offspring of these forms were cultivated in the same environments. It was shown that genetic polymorphism of U. pinnatifida in Peter the Great Bay is low. The genetic distance among five populations representing three forms of U. pinnatifida did not exceed 0.2. The offspring of three forms grown in the same environmental conditions became, in general, morphologically similar. Combination of genetic analysis and cultivation in the same environmental conditions of three morphologically different forms of U. pinnatifida from Peter the Great Bay suggested that their specific morphology is not genetically fixed and is the result of ontogenetic adaptation to the local environment.