Tannery sludge valorization through zeolite-assisted anaerobic process for short-chain fatty acids (SCFAs) production.

Tannery sludge, a challenging waste, was utilized as a substrate for the production of Short-Chain Fatty Acids (SCFAs) through a series of six thermophilic Continuous Stirred-Tank Reactor runs. The sludge was subjected to a mild thermal pre-treatment and incorporated zeolites (chabazite in run II, and clinoptilolite in run III) in the acidification process. Results highlighted zeolites' impact on chromium concentration and the SCFAs/CODSOL ratio. Ammonia release remained consistent at around 47 % and 51 % for run I and II, respectively, but surpassed 60% in run III, suggesting limited zeolite effectiveness in NH4 absorption. Chromium release in the liquid fraction, due to thermal pretreatment, reached 335 mg/L. While in tests without zeolite, complete removal proved challenging, in zeolite-amended runs, complete removal was achieved, showcasing the materials' heavy metal absorption capacity. SCFA concentrations reached 20260 mgCOD/L, with acidification efficiency varying; runs I and III had ratios around 0.70 COD/COD, while run II showed substantial improvement (0.92) with chabazite. Anaerobic fermentation-digestion mass balance indicated a 41% reduction in landfill sludge mass, reducing its environmental footprint while yielding valuable byproducts like biogas and SCFAs. These findings underscore zeolites' potential in heavy metal absorption and acidification process enhancement, paving the way for applications with tannery sludge.

Drosophila Doublefault protein coordinates multiple events during male meiosis by controlling mRNA translation.

During the extended prophase of Drosophila gametogenesis, spermatocytes undergo robust gene transcription and store many transcripts in the cytoplasm in a repressed state, until translational activation of select mRNAs in later steps of spermatogenesis. Here, we characterize the Drosophila Doublefault (Dbf) protein as a C2H2 zinc-finger protein, primarily expressed in testes, that is required for normal meiotic division and spermiogenesis. Loss of Dbf causes premature centriole disengagement and affects spindle structure, chromosome segregation and cytokinesis. We show that Dbf interacts with the RNA-binding protein Syncrip/hnRNPQ, a key regulator of localized translation in Drosophila We propose that the pleiotropic effects of dbf loss-of-function mutants are associated with the requirement of dbf function for translation of specific transcripts in spermatocytes. In agreement with this hypothesis, Dbf protein binds cyclin B mRNA and is essential for translation of cyclin B in mature spermatocytes.

CPAP promotes timely cilium disassembly to maintain neural progenitor pool.

A mutation in the centrosomal-P4.1-associated protein (CPAP) causes Seckel syndrome with microcephaly, which is suggested to arise from a decline in neural progenitor cells (NPCs) during development. However, mechanisms ofNPCs maintenance remain unclear. Here, we report an unexpected role for the cilium inNPCs maintenance and identifyCPAPas a negative regulator of ciliary length independent of its role in centrosome biogenesis. At the onset of cilium disassembly,CPAPprovides a scaffold for the cilium disassembly complex (CDC), which includes Nde1, Aurora A, andOFD1, recruited to the ciliary base for timely cilium disassembly. In contrast, mutatedCPAPfails to localize at the ciliary base associated with inefficientCDCrecruitment, long cilia, retarded cilium disassembly, and delayed cell cycle re-entry leading to premature differentiation of patientiPS-derivedNPCs. AberrantCDCfunction also promotes premature differentiation ofNPCs in SeckeliPS-derived organoids. Thus, our results suggest a role for cilia in microcephaly and its involvement during neurogenesis and brain size control.

The developing Drosophila eye - a new model to study centriole reduction.

In the developing Drosophila eye, the centrioles of the differentiating retinal cells are not surrounded by the microtubule-nucleating γ-tubulin, suggesting that they are unable to organize functional microtubule-organizing centers. Consistent with this idea, Cnn and Spd-2, which are involved in γ-tubulin recruitment, and the scaffold protein Plp, which plays a role in the organization of the pericentriolar material, are lost in the third-instar larval stage. However, the centrioles maintain their structural integrity, and both the parent centrioles accumulate Asl and Ana1. Although the loading of Asl points to the acquisition of the motherhood condition, the daughter centrioles fail to recruit Plk4 and do not duplicate. However, it is surprising that the mother centrioles that accumulate Plk4 also never duplicate. This suggests that the loading of Plk4 is not sufficient, in this system, to allow centriole duplication. By halfway through pupal life, the centriole number decreases and structural defects, ranging from being incomplete or lacking B-tubules, are detected. Asl, Ana1 and Sas-4 are still present, suggesting that the centriole integrity does not depend on these proteins.

The "transition zone" of the cilium-like regions in the Drosophila spermatocytes and the role of the C-tubule in axoneme assembly.

The fruit-fly Drosophila melanogaster harbours different types of ciliary structures: ciliary projections associated with neurons of type I and cilium-like regions (CLRs) found during male gametogenesis. The latter deserve particular attention since they are morphologically similar to vertebrate primary cilia and transform into the sperm axonemes during spermiogenesis. Although, all the centrioles are able to organize the CLRs, we found that the mother centriole docks first to the plasma membrane suggesting a new intrinsic functional asymmetry between the parent centrioles. We also show that the CLRs lack the Y-links that connect the axoneme doublets with the plasma membrane in conventional primary cilia. Moreover, the C-tubules, that are lacking in the axoneme of the primary cilia, persisted along the CLRs albeit modified into longitudinal blades. Remarkably, mutant flies in which the CLRs are devoid of the C-tubules or their number is reduced lack sperm axonemes or have incomplete axonemes. Therefore, the C-tubules are dispensable for the assembly of the CLRs but are essential for sperm axoneme elongation and maintenance in Drosophila.

Does Unc-GFP uncover ciliary structures in the rhabdomeric eye of Drosophila?

The uncoordinated (unc) gene product, a potential ortholog of mammalian orofaciodigital syndrome 1 (Ofd1), is involved in the assembly of the ciliary axoneme in Drosophila and it is, therefore, constrained to cell types that have ciliary structures, namely type 1 sensory neurons and male germ cells. Here, we show that evenly spaced Unc-GFP spots are present in the eye imaginal discs of third-instar larvae. These spots are restricted to the R8 photoreceptor cell of each ommatidium in association with mother centrioles. This finding is unexpected because the Drosophila eye is of the rhabdomeric type and would be expected to lack ciliary structures.

The Drosophila centriole - conversion of doublets into triplets within the stem cell niche.

We report, here, that two distinct centriole lineages exist in Drosophila: somatic centrioles usually composed by microtubule doublets and germ line centrioles characterized by triplets. Remarkably, the transition from doublets to triplets in the testis occurs within the stem cell niche with the formation of the C-tubule. We demonstrated that the old mother centriole, which stays in the apical cytoplasm of the male germline stem cells (GSCs), is invariably composed of triplets, whereas its daughter is always built of mixed doublets and triplets. This difference represents the first documentation of a structural asymmetry between mother and daughter centrioles in Drosophila GSCs and might reflect a correlation between the architecture of parent centrioles and their ability to recruit centrosomal proteins. We also found that the old mother centriole is linked to the cell membrane by distinct projections that might play an important role in keeping its apical position during centrosome separation.

Feasibility of thermophilic anaerobic processes for treating waste activated sludge under low HRT and intermittent mixing.

Thermophilic anaerobic digestion (AD) arises as an optimized solution for the waste activated sludge (WAS) management. However, there are few feasibility studies using low solids content typically found in the WAS, and that consider uncommon operational conditions such as intermittent mixing and low hydraulic retention time (HRT). In this investigation, a single-stage pilot reactor was used to treat WAS at low HRT (13, 9, 6 and 5 days) and intermittent mixing (withholding mixing 2 h prior feeding). Thermophilic anaerobic digestion (55 °C) was initiated from a mesophilic digester (35 °C) by the one-step startup strategy. Although instabilities on partial alkalinity (1245-3000 mgCaCO3/L), volatile fatty acids (1774-6421 mg/L acetic acid) and biogas production (0.21-0.09 m3/m3reactor.d) were observed, methanogenesis started to recover in 18 days. The thermophilic treatment of WAS at 13 and 9 days HRT efficiently converted VS into biogas (22 and 21%, respectively) and achieved high biogas yield (0.24 and 0.22 m3/kgVSfed, respectively). Intermittent mixing improved the retention of methanogens inside the reactor and reduced the washout effect even at low HRT (<9 days). The negative thermal balance found was influenced by the low solids content in the WAS (2.1% TS) and by the heat losses from the digester walls. The energy balance and economic analyses demonstrated the feasibility of thermophilic AD of WAS in a hypothetical full-scale system, when the heat energy could be recovered from methane in a scenario of higher solids concentration in the substrate (>5% TS).

Structure and Evolution of Insect Sperm: New Interpretations in the Age of Phylogenomics.

This comprehensive review of the structure of sperm in all orders of insects evaluates phylogenetic implications, with the background of a phylogeny based on transcriptomes. Sperm characters strongly support several major branches of the phylogeny of insects-for instance, Cercophora, Dicondylia, and Psocodea-and also different infraordinal groups. Some closely related taxa, such as Trichoptera and Lepidoptera (Amphiesmenoptera), differ greatly in sperm structure. Sperm characters are very conservative in some groups (Heteroptera, Odonata) but highly variable in others, including Zoraptera, a small and morphologically uniform group with a tremendously accelerated rate of sperm evolution. Unusual patterns such as sperm dimorphism, the formation of bundles, or aflagellate and immotile sperm have evolved independently in several groups.

Procentriole assembly without centriole disengagement - a paradox of male gametogenesis.

Disengagement of parent centrioles represents the licensing process to restrict centriole duplication exactly once during the cell cycle. However, we provide compelling evidence that this general rule is overridden in insect gametogenesis, when distinct procentrioles are generated during prophase of the first meiosis while parent centrioles are still engaged. Moreover, the number of procentrioles increases during the following meiotic divisions, and up to four procentrioles were found at the base of each mother centriole. However, procentrioles fail to organize a complete set of A-tubules and are thus unable to function as a template for centriole formation. Such a system, in which procentrioles form but halt growth, represents a unique model to analyze the process of cartwheel assembly and procentriole formation.

The cilium-like region of the Drosophila spermatocyte: an emerging flagellum?

Primary cilia and flagella are distinct structures with different functions in eukaryotic cells. Despite the fact that they share similar basic organization and architecture, a direct developmental continuity among them has not been reported until now. The primary cilium is a dynamic structure that typically assembles and disassembles during mitotic cell cycles, whereas the sperm axoneme is nucleated by the centriole inherited by the differentiating spermatid at the end of meiosis. Fruit flies display a remarkable exception to this general rule. Drosophila spermatocytes have an unusual axoneme-based structure reminiscent of primary cilia (the cilium-like region, or CLR). This structure persists through the meiotic divisions when it is internalized with the centriole to organize the centrosome and is finally inherited by young spermatids. Examination of elongating spermatids by transmission electron microscopy (EM) and cold regrowth experiments suggests that the motile axoneme derives directly from the elongation and remodelling of the immotile CLR. Both the CLR and elongating spermatid flagella have incomplete C-tubules that form longitudinal sheets associated with the B-tubule wall, unlike axonemes of other organisms in which C-tubules stop growing at the transition between the basal body and the axonemal doublets. Moreover, both the CLR and spermatid flagella lack a structured transition zone, a characteristic feature of ciliated cells. Uncoordinated (unc) mutants that lack C-remnants have short centrioles, suggesting that the C-sheets play a role in the elongation of the centriole after it docks to the cell membrane. The structural similarities between CLR and sperm axoneme suggest that the CLR can be considered as the basal region of the future axoneme and could represent the start point for its elongation.

Bacteria of the genus Erwinia found in the spermatheca of the laurel psyllid Trioza alacris.

Psylloidea are economically important insects causing serious damage to plants by direct feeding and/or vectoring bacterial pathogens. Results reported here indicate the presence of extracellular bacteria in the spermatheca of egg-laying Trioza alacris females. One phylotype, sharing 99 % identity with the non-phytopathogenic bacterium Erwinia tasmaniensis, was identified regardless of methods applied or insect sampling year and location. This is the first study, achieved by ultrastructural, cultural, and 16S rRNA gene-based analysis, of an insect spermatheca microbiota.

Parasitic castration by Xenos vesparum depends on host gender.

Host castration represents a mechanism used by parasites to exploit energy resources from their hosts by interfering with their reproductive development or to extend host lifespan by removing risks associated with reproductive activity. One of the most intriguing groups of parasitic castrators is represented by the insects belonging to the order Strepsiptera. The macroparasite Xenos vesparum can produce dramatic phenotypic alterations in its host, the paper wasp Polistes dominula. Parasitized female wasps have undeveloped ovaries and desert the colony without performing any social task. However, very little attention has been given to the parasitic impact of X. vesparum on the male phenotype. Here, we investigated the effects of this parasite on the sexual behaviour and the morpho-physiology of P. dominula males. We found that, differently from female wasps, parasitized males are not heavily affected by Xenos: they maintain their sexual behaviour and ability to discriminate between female castes. Furthermore, the structure of their reproductive apparatus is not compromised by the parasite. We think that our results, demonstrating that the definition of X. vesparum as a parasitoid does not apply to infected males of P. dominula, provide a new perspective to discuss and maybe reconsider the traditional view of strepsipteran parasites.

Oxygen limitation in aerobic polyhydroxyalkanoates production from sewage sludge anaerobic fermentation liquids under low and medium organic loading rate.

The present study describes the microbial production of polyhydroxyalkanoates (PHA) from thermally pre-treated sewage sludge at pilot scale level, investigating for the first time the effect of the organic loading rate (OLR) under oxygen limitation on biomass storage properties and kinetics. Polymer characteristics have been also evaluated. The selection/enrichment of PHA-storing biomass was successfully achieved in a Sequencing Batch Reactor (SBR) under short hydraulic retention time (HRT; 2 days). Low OLR (2.05 g COD/L d) was ideal for the selection of an efficient PHA-producing consortium cultivated under limited oxygen availability. In the fed-batch accumulation conducted under high DO regime, such biomass was characterized by 51% of PHA content on cell dry weight, with a related storage yield (YP/Sbatch) of 0.61 CODPHA/CODS. On the contrary, medium OLR (4.56 g COD/L d) was not technically feasible to sustain the required consortium's selection under low DO regime. The PHA produced by biomass cultivated under low DO regime was characterized higher thermal stability and crystalline domain compared to PHA traditionally produced under high DO regime. The mass balance assessment highlighted a global yield of 51 g PHA/kg VS (volatile solids of thickened sludge), which was 9% lower than yield obtained under high DO regime, in the face of a realistic reduction of the energy cost of the process.

Evidence for intraflagellar transport in butterfly spermatocyte cilia.

In the model organism insect Drosophila melanogaster short cilia assemble on spermatocytes that elaborate into 1.8 mm long flagella during spermatid differentiation. A unique feature of these cilia/flagella is their lack of dependence on intraflagellar transport (IFT) for their assembly. Here, we show that in the common butterfly Pieris brassicae, the spermatocyte cilia are exceptionally long: about 40 µm compared to less than 1 µm in Drosophila. By transmission electron microscopy, we show that P. brassicae spermatocytes display several features not found in melanogaster, including compelling evidence of IFT structures and features of motile cilia.

Defensive spiroketals from Asceles glaber (Phasmatodea): absolute configuration and effects on ants and mosquitoes.

Insects are the largest and most diverse group of organisms on earth, with over 1,000,000 species identified to date. Stick insects ("walkingsticks" or "phasmids", Order Phasmatodea) are known for and name-derived from their camouflage that acts as a primary line of defense from predation. However, many species also possess a potent chemical defense spray. Recently we discovered that the spray of Asceles glaber contains spiroketals [a confirmed major component: (2S,6R)-(-)(E)-2-methyl-1,7-dioxaspiro[5.5]undecane, and a tentatively identified minor component: 2-ethyl-1,6-dioxaspiro[4.5]decane] and glucose. In this paper, we: 1) illustrate the identification of spiroketals and glucose in the defense spray of A. glaber by using Nuclear Magnetic Resonance (NMR), Gas Chromatography/Mass Spectrometry (GC/MS), and comparison with a synthetic reference sample; 2) provide the elucidation of the absolute configuration of the major spiroketal in that defense spray; and 3) demonstrate the effect of this compound and its enantiomer on both fire ants (Solenopsis invicta) and mosquitoes (Aedes aegypti).

Producing volatile fatty acids and polyhydroxyalkanoates from foods by-products and waste: A review.

Dairy products, extra virgin olive oil, red and white wines are excellent food products, appreciated all around the world. Their productions generate large amounts of by-products which urge for recycling and valorization. Moreover, another abundant waste stream produced in urban context is the Organic Fraction of Municipal Solid Wastes (OFMSW), whose global annual capita production is estimated at 85 kg. The recent environmental policies encourage their exploitation in a biorefinery loop to produce Volatile Fatty Acids (VFAs) and polyhydroxyalkanoates (PHAs). Typically, VFAs yields are high from cheese whey and OFMSW (0.55-0.90 gCOD_VFAs/gCOD), lower for Olive Mill and Winery Wastewaters. The VFAs conversion into PHAs can achieve values in the range 0.4-0.5 gPHA/gVSS for cheese whey and OFMSW, 0.6-0.7 gPHA/gVSS for winery wastewater, and 0.2-0.3 gPHA/gVSS for olive mill wastewaters. These conversion yields allowed to estimate a huge potential annual PHAs production of about 260 M tons.

Cilium induction triggers differentiation of glioma stem cells.

Glioblastoma multiforme (GBM) possesses glioma stem cells (GSCs) that promote self-renewal, tumor propagation, and relapse. Understanding the mechanisms of GSCs self-renewal can offer targeted therapeutic interventions. However, insufficient knowledge of GSCs' fundamental biology is a significant bottleneck hindering these efforts. Here, we show that patient-derived GSCs recruit elevated levels of proteins that ensure the temporal cilium disassembly, leading to suppressed ciliogenesis. Depleting the cilia disassembly complex components is sufficient to induce ciliogenesis in a subset of GSCs via relocating platelet-derived growth factor receptor-alpha (PDGFR-α) to a newly induced cilium. Importantly, restoring ciliogenesis enabled GSCs to switch from self-renewal to differentiation. Finally, using an organoid-based glioma invasion assay and brain xenografts in mice, we establish that ciliogenesis-induced differentiation can prevent the infiltration of GSCs into the brain. Our findings illustrate a role for cilium as a molecular switch in determining GSCs' fate and suggest cilium induction as an attractive strategy to intervene in GSCs proliferation.

Human brain organoids assemble functionally integrated bilateral optic vesicles.

During embryogenesis, optic vesicles develop from the diencephalon via a multistep process of organogenesis. Using induced pluripotent stem cell (iPSC)-derived human brain organoids, we attempted to simplify the complexities and demonstrate formation of forebrain-associated bilateral optic vesicles, cellular diversity, and functionality. Around day 30, brain organoids attempt to assemble optic vesicles, which develop progressively as visible structures within 60 days. These optic vesicle-containing brain organoids (OVB-organoids) constitute a developing optic vesicle's cellular components, including primitive corneal epithelial and lens-like cells, retinal pigment epithelia, retinal progenitor cells, axon-like projections, and electrically active neuronal networks. OVB-organoids also display synapsin-1, CTIP-positive myelinated cortical neurons, and microglia. Interestingly, various light intensities could trigger photosensitive activity of OVB-organoids, and light sensitivities could be reset after transient photobleaching. Thus, brain organoids have the intrinsic ability to self-organize forebrain-associated primitive sensory structures in a topographically restricted manner and can allow interorgan interaction studies within a single organoid.