The Neutral Detergent Fiber Digestibility of Some Tropical Grasses at Different Stage of Maturity

The digestibility of neutral detergent fiber (IVNDFD) was determined by Telly and Terry methods in vitro on 5 tropical grasses species, Sorghum, Themeda, Iseilema, Brachyacne and Dicanthium. Stem and leaf samples were harvested at different maturity stages, started from early flowering stage to the stage when the grasses were dried. In general, IVNDFD ranged from 22% to 41%. Stages of maturity affected IVNDFD in 4 species; IVNDFD was higher in the stems than in the leaves for 2 species out of 5 species of grasses; the rest was similar. There was no correlation between NDF and IVNDFD, showing that NDF degradability in the rumen was vary. Digestibility potential of NDF (PDNDF) varied from 21% to 44% and has negative correlation with IVNDFD (r=0.75). Growth affected PDNDF in 2 species; and 3 out 5 species observed showed PDNDF in the leaves was higher than that in the stems. Negative correlation was exist between dry matter digestibility (IVDMD), water soluble extract (WSE) and protein with PDNDF.  Grasses with stated PDNDF values have relatively high NDF retention in the rumen, which will cause low NDF or dry matter consumption. (Animal Production 11(3): 189-195 (2009)Key Words: NDF digestibility, tropical grasses, stem, leaves, maturity stag

Contribution of subsurface peat to CO2 and CH4 fluxes in a neotropical peatland

Tropical peatlands play an important role in the global carbon cycling but little is known about factors regulating carbon dioxide (CO2) and methane (CH4) fluxes from these ecosystems. Here, we test the hypotheses that (i) CO2 and CH4 are produced mainly from surface peat and (ii) that the contribution of subsurface peat to net C emissions is governed by substrate availability. To achieve this, in situ and ex situ CO2 and CH4 fluxes were determined throughout the peat profiles under three vegetation types along a nutrient gradient in a tropical ombrotrophic peatland in Panama. The peat was also characterized with respect to its organic composition using C-13 solid state cross-polarization magic-angle spinning nuclear magnetic resonance spectroscopy. Deep peat contributed substantially to CO2 effluxes both with respect to actual in situ and potential ex situ fluxes. CH4 was produced throughout the peat profile with distinct subsurface peaks, but net emission was limited by oxidation in the surface layers. CO2 and CH4 production were strongly substrate-limited and a large proportion of the variance in their production (30% and 63%, respectively) was related to the quantity of carbohydrates in the peat. Furthermore, CO2 and CH4 production differed between vegetation types, suggesting that the quality of plant-derived carbon inputs is an important driver of trace gas production throughout the peat profile. We conclude that the production of both CO2 and CH4 from subsurface peat is a substantial component of the net efflux of these gases, but that gas production through the peat profile is regulated in part by the degree of decomposition of the peat

Structure-Function Relationships in HpuAB, the Gonococcal Bipartite TonB-dependent Transport System

Gonorrhea, a prevalent sexually transmitted infection affecting millions annually worldwide, is caused by Neisseria gonorrhoeae (Ngo), a superbug resistant to all antibiotic classes. Compounding the challenge, the absence of protective immunity upon infection allows for reinfection, and a viable vaccine against gonococcal infection remains elusive. In response to infection, the human host deploys nutritional immunity, sequestering essential metals like iron from invading bacteria, using metal binding proteins. To overcome this, Ngo employs outer-membrane TonB-dependent transporters (TdTs), like HpuAB, to acquire iron from host metal binding proteins, such as hemoglobin (Hb). Part of our study focused on HpuA, the lipoprotein component of the HpuAB system. Mutations targeting hydrophobic residues crucial for Hb interaction were studied. Results demonstrated that without HpuB, strains failed to grow, emphasizing HpuB\u27s role in iron internalization. Notably, when HpuB is produced, deletion and insertion mutations in loop 2 of HpuA affected growth and binding to Hb. Further investigations into HpuB, the transmembrane protein of the HpuAB system, uncovered essential loop regions for binding and growth on Hb as a sole iron source. Deletion mutations in loops 2, 3, and 4 facilitated binding and growth independently of HpuA production. Intriguingly, mutations in loop 7 abrogated binding and impaired growth in the absence of HpuA, but partial growth and full binding recovery occurred when HpuA was present. This highlighted the importance of loop 7 in iron acquisition and suggested a potential role for both HpuA and HpuB in the binding Hb. As a combination of non-binding TdT mutants is hypothesized to have the potential to improve vaccine efficacy and provide protection, identifying non-binding HpuB mutants could be important. In summary, this research sheds light on the intricacies of the HpuAB system, contributing valuable insights that could inform the development of an effective gonorrhea vaccine

Aspen Tension Wood Fibers Contain β-(1→4)-Galactans and Acidic Arabinogalactans Retained by Cellulose Microfibrils in Gelatinous Walls

Contractile cell walls are found in various plant organs and tissues such as tendrils, contractile roots, and tension wood. The tension-generating mechanism is not known but is thought to involve special cell wall architecture. We previously postulated that tension could result from the entrapment of certain matrix polymers within cellulose microfibrils. As reported here, this hypothesis was corroborated by sequential extraction and analysis of cell wall polymers that are retained by cellulose microfibrils in tension wood and normal wood of hybrid aspen (Populus tremula × Populus tremuloides). β-(1→4)-Galactan and type II arabinogalactan were the main large matrix polymers retained by cellulose microfibrils that were specifically found in tension wood. Xyloglucan was detected mostly in oligomeric form in the alkali-labile fraction and was enriched in tension wood. β-(1→4)-Galactan and rhamnogalacturonan I backbone epitopes were localized in the gelatinous cell wall layer. Type II arabinogalactans retained by cellulose microfibrils had a higher content of (methyl)glucuronic acid and galactose in tension wood than in normal wood. Thus, β-(1→4)-galactan and a specialized form of type II arabinogalactan are trapped by cellulose microfibrils specifically in tension wood and, thus, are the main candidate polymers for the generation of tensional stresses by the entrapment mechanism. We also found high β-galactosidase activity accompanying tension wood differentiation and propose a testable hypothesis that such activity might regulate galactan entrapment and, thus, mechanical properties of cell walls in tension wood.This work was supported by the Swedish Governmental Agency for Innovation Systems, the Swedish Research Council, the Russian Foundation for Basic Research (grant nos. 15–04–02560 and 15–04–05721), and the Biotechnology and Biological Sciences Research Council (grant no. BB/G016240/1 and funds from the Sustainable Energy Centre Cell Wall Sugars Programme).This is the author accepted manuscript. The final version is available from the American Society of Plant Biologists via http://dx.doi.org/10.​1104/​pp.​15.​0069

Aspen Tension Wood Fibers Contain β-(1---> 4)-Galactans and Acidic Arabinogalactans Retained by Cellulose Microfibrils in Gelatinous Walls.

Contractile cell walls are found in various plant organs and tissues such as tendrils, contractile roots, and tension wood. The tension-generating mechanism is not known but is thought to involve special cell wall architecture. We previously postulated that tension could result from the entrapment of certain matrix polymers within cellulose microfibrils. As reported here, this hypothesis was corroborated by sequential extraction and analysis of cell wall polymers that are retained by cellulose microfibrils in tension wood and normal wood of hybrid aspen (Populus tremula × Populus tremuloides). β-(1→4)-Galactan and type II arabinogalactan were the main large matrix polymers retained by cellulose microfibrils that were specifically found in tension wood. Xyloglucan was detected mostly in oligomeric form in the alkali-labile fraction and was enriched in tension wood. β-(1→4)-Galactan and rhamnogalacturonan I backbone epitopes were localized in the gelatinous cell wall layer. Type II arabinogalactans retained by cellulose microfibrils had a higher content of (methyl)glucuronic acid and galactose in tension wood than in normal wood. Thus, β-(1→4)-galactan and a specialized form of type II arabinogalactan are trapped by cellulose microfibrils specifically in tension wood and, thus, are the main candidate polymers for the generation of tensional stresses by the entrapment mechanism. We also found high β-galactosidase activity accompanying tension wood differentiation and propose a testable hypothesis that such activity might regulate galactan entrapment and, thus, mechanical properties of cell walls in tension wood.This work was supported by the Swedish Governmental Agency for Innovation Systems, the Swedish Research Council, the Russian Foundation for Basic Research (grant nos. 15–04–02560 and 15–04–05721), and the Biotechnology and Biological Sciences Research Council (grant no. BB/G016240/1 and funds from the Sustainable Energy Centre Cell Wall Sugars Programme).This is the author accepted manuscript. The final version is available from the American Society of Plant Biologists via http://dx.doi.org/10.​1104/​pp.​15.​0069

Soil fungi, but not bacteria, track vegetation reassembly across a 30-year restoration chronosequence in the northern jarrah forest, Western Australia

Plant communities have been the primary focus of ecological restoration initiatives; however, the integration of the soil microbiome has become of interest to restoration practice and theory. The inter-dependent nature of the above- and belowground biological environments has led to assumptions that reciprocal shifts in community compositions will occur in response to disturbance and restoration. Ecological restoration of post-mining landscapes within the northern jarrah forest re-instates vegetation communities that are representative of those in adjacent reference forest. The limited studies of soil microbial communities have not addressed whether these communities recover along similar trajectories to plant communities aboveground. Here, a 30-year restoration chronosequence of vegetation development was compared with that of the belowground assemblages of bacteria and fungi, identified using environmental DNA methods. Novel findings of this study highlight similarities between restoration trajectories of fungal and vegetation assemblages, though both remained distinct from reference jarrah forest compositions after 27-years. In contrast, soil bacterial assemblages in restored jarrah forest re-assembled rapidly, with substrate depth being a greater driver of composition than vegetation. Explanatory environmental variables, such as litter cover and initial fertiliser application, were significantly associated with vegetation composition. High covariance among physico-chemical factors made it difficult to establish influences of individual variables on bacterial and fungal communities. Litter depth was significantly associated with fungal composition across the restoration chronosequence, whilst available potassium was associated with both bacterial and fungal community composition. My findings add to a growing body of literature which acknowledges the rich diversity of the belowground microbial community, and the potential for their use as predictors of restoration trajectories. Future research could focus on direct associations between fungi and plant communities, such as potential for fungal inoculation to assist in the rapid reinstatement of missing plants which rely on symbiotic associations with the belowground microbiome

Geochemical and petrological constraints on the origin of the neoproterozoic Urucum iron formation, Santa Cruz deposit, Brazil.

Programa de P?s-Gradua??o em Evolu??o Crustal e Recursos Naturais. Departamento de Geologia, Escola de Minas, Universidade Federal de Ouro Preto.O Grupo Jacadigo-Boqui, situado no SW do Brasil e SE da Bolivia, hospeda a Forma??o Ferr?fera e Manganes?fera (FF-FMn) do Urucum; um das ocorr?ncias mais conhecidas e arquet?pica do Neoproterozoico e a ultima grande express?o de deposi??o conjunta de Fe e Mn do Pr?-cambriano. A sequ?ncia sedimentar do GrupoJacadigo-Boqui foi depositada em rifts desenvolvidos no paleocontinente Amazonas-Rio Apa, paralelamente a um evento de glacia??o e o come?o do ciclo Brasiliano. A FF do Urucum ? caracterizada por uma assembl?ia metam?rfica de baixo a muito baixo grau, geralmente composta por hematita, cherte e carbonatos da s?rie Fe-dolomite-ankerita. EMP e LA-ICP-MS foram usados para determinar a composi??o qu?mica de hematitas dos facies carbon?tico e silicoso encontrados no morro Santa Cruz, Brasil. Tr?s est?gios de mineraliza??o foram reconhecidos com base na textura e morfologia: (i) hematita an?dricamicrocristalina, (ii) hematita sub?drica a eu?drica microespecular e (iii) microplac?ide. Os resultados da EMP mostram composi??es qu?micas quase puras em Fe2O3 com quantidades tra?o de impurezas. Os resultados das analises de EMP e LA-ICP-MS mostram concentra??es similares de elementos tra?o para todos os est?gios, com pequena margem de varia??o, indicando uma redistribui??o p?s-deposicional relativamente limitada dos elementos tra?o. A an?lise fatorial das composi??es discriminou quatro grupos de elementos tra?o: (i) elementos incorporados na estrutura cristalina das hematitas (Ti, Al, V, Mn, Mg), (ii) associados com contamina??o por carbonatos (Mg, Ca, Mn, P, Sr), associados com contamina??o por cherte (Si), e hidr?genos adsorvidos em part?culas precursoras (ETR, Ba, U, Th, Zr, Hf, Cu). Padr?es de elementos terras raras (ETR), normalizados com folhelho, com caracter?sticas marinhas e raz?es de Zr/Hf e Th/U fracionadas sugerem uma recristaliza??o a partir de sedimentos hidr?genos compostos por ferrihidrita. A hematita microcristalina foi formada precocemente durante a diag?nese, atrav?s de desidrata??o, no estado s?lido,de part?culas amorfas de ferrihidrita; equanto que as variedades microespecular e microplac?ide se formaram por processos de difus?o durante est?gios posteriores de diag?nese-metamorfismo de baixo grau relacionado com o inicio da Orogenia Brasiliana.Essas transforma??es ocorreram concomitantemente e, possivelmente, envolveram a participa??o de fluidos hipogen?ticos basinais, os quais promoveram o enriquecimento da FF atrav?s da lixivia??o de chert. Fluidos superg?nicos promoveram a lixivia??o de minerais de ganga, por?mn?o modificaram significativamente a textura e composi??o qu?mica de hematitas prim?rias. Anomalias negativas reais de Ce e raz?es fracionadas de Th/U indicam que o os sedimentos precursores foram depositados em uma bacia estratificada, acima da fronteira redox, em condi??es ?xicas. A presen?a de pel?ides de hematita corrobora um ambiente marinho raso; pr?ximo ao n?vel de base das ondas em tempo normal. Esta camada ?xica superficial apresentava uma conex?o com o oceano aberto, baseado nas assinaturas de ETR caracteristicamente marinhas, particularmente a pronunciada deple??o em ETR leves, mas tamb?m recebeu um influxo de ?gua doce, indicado por raz?es de Zr/Hf dentro do campo CHARAC (charge-and-radius-controlled behavior).The Jacadigo-Boqui Group, SW Brazil and SE Bolivia, hosts the so-called Urucum Iron and Manganese Formation (IF-MnF); one of the most well-known and archetypaloccurrence of Neoproterozoic ageand the last large expression of coupled Fe and Mn deposition of the Precambrian. This sedimentary sequence was developed in rifts within the Amazon-Rio Apapaleocontinent,coeval witha Neoproterozoic glaciation event and the early BrasilianoOrogeny. The Urucum IF hosts a very low-grade metamorphic assemblage, generally composed of hematite, chert and carbonates of the Fe-dolimite-ankerite series. EMP and LA-ICPMS were used to determine the chemical composition of hematites from the carbonaceous and siliceous facies IF found in the Santa Cruz hill, Brazil. Three mineralization stages wererecognized based on the texture and morphology of the hematites: (i) anhedral microcrystalline, (ii) subhedral to euhedralmicrospecular and (ii) microplaty.EMP resultsshow nearly pure Fe2O3 compositions, with predominantly trace amounts of impurities. Both EMPand LA-ICP-MSresultsshow similar trace element concentrations for all hematite stages, which vary within a relatively narrow range suggesting limited postdepositional redistribution. Statistical Factor Analysis discriminated four groups of trace elements: (i) incorporated in the crystalline structure of hematite (Ti, Al, V, Mn, Mg), (ii) associated with carbonate contamination (Mg, Ca, Mn, P, Sr), (iii) associated with chertcontamination (Si), (iv) and hydrogenous adsorbed on the precursor particles(REE, Ba, U, Th,Zr, Hf, Cu). Seawater-like shale-normalized REE patterns and fractionated Zr/Hf and Th/U ratios indicate a recrystallization from precursor hydrogenous sediments composed offerrihydrite.Microcrystalline hematite was formed earlyduring diagenesisthrough solid-state dehydration of amorphous ferrihydrite; while the microspecular and microplaty varieties were formed predominantly via diffusions processes during diagenesis-low grade metamorphismassociated with the early BrasilianoOrogeny. These transformations were coeval and likely involved the participation of hypogenemineralizingfluids (basin brines), which led to chert leaching. Supergene fluids further leached the gangue minerals, but led to small modifications in the texture and trace element composition of primary hematites. Real negative Ce anomalies and fractionated Th/U ratiosindicate that theprecursor sedimentswere deposited in a stratified basin, above a redox chemocline, under well-oxygenated conditions. The presence of hematite peloids corroborates a shallow marine setting, near the fair-weather wave base. This surface oxic layer was likely connected with the open ocean, based on the typical marine REE signature of the hematites, particularly the pronounced LREE depletion, but also received influx of freshwater, indicated by varied by predominantly CHARAC (charge-and-radius-controlled behavior) Zr/Hf ratios

New Roads to Genomic Imbalance: Microrna- and Protein Phosphatase-Mediated Regulation of Mitosis

The Spindle Assembly Checkpoint (SAC) works to maintain the genomic balance by monitoring the correctness of attachments between the chromosomes and microtubules during early cell division (mitosis). Importantly, chromosome missegregation and genomic instability is caused by defects in SAC function, which can lead to cell transformation and cancer. Moreover, malfunction of SAC can confer resistance to microtubule-targeting drugs (MTAs) such as paclitaxel. The identification and functional characterization of novel SAC regulating biomolecules and analysis of their expression profiles in tumor cells may in the future facilitate improved cancer diagnosis and predict patient’s response to MTA therapy. The microRNA- (miRNA) and protein phosphatase-mediated regulation of mitotic signaling were investigated in my thesis. First, to identify new miRNAs that regulate SAC signaling, a cell-based high-throughput screen (HTS) was performed to test the ability of 810 different pre-miRNAs to override a drug imposed M phase arrest. The HTS led to the discovery of miR-378a-5p and miR-493-3p as suppressors of MTA action in vitro. Further molecular biology experiments revealed that miR-378a-5p and miR-493-3p negatively regulated the expression of AURKB and MAD2L1, respectively. Retrospective analysis of ovarian and breast cancer samples in vivo indicated deregulated expression of both miRNAs in different tumor grades and subtypes compared to healthy tissues. Moreover, high expression of miR-493-3p was found to associate with reduced survival of ovarian and breast cancer patients with aggressive tumors, especially if the patients were treated with paclitaxel chemotherapy in comparison to epirubicin. Secondly, the functions of the Dual specificity protein phosphatase 3 (Dusp3) in dividing cells were explored. The maintenance of bipolar spindle architecture during mitosis was found to be dependent on Dusp3. In summary, the previously unknown mitotic functions for three biomolecules, namely miR-378a-5p, miR-493-3p and Dusp3 were identified. The determination of miR-378a-5p and miR-493-3p expression profiles, in tumor samples can in the future assist in cancer subtyping and selecting the most effective chemotherapy for ovarian and breast cancer patients with advanced disease.Siirretty Doriast