Temperature fluctuation alleviates the negative effects of warming on marine diatoms: comparison between <i>Thalassiosira</i> sp. and <i>Nitzschia closterium</i> f. <i>minutissima</i>

Marine phytoplankton are subjected to a wide range of environmental heterogeneity, from mean climate change to natural fluctuations under the climate change scenario. These changes include changes in the frequency of temperature fluctuations in the sea surface. Here we conducted semi-continuous incubation experiments on two ecologically significant marine diatom species, Thalassiosira sp. and Nitzschia closterium f. minutissima, to examine their physiological responses to ocean warming and temperature fluctuation (±4 °C) under low (20 °C) and high (25 °C) average temperatures. Our results demonstrate that temperature fluctuation alleviated the negative effects of elevated temperatures on the growth of both species. For Thalassiosira sp., warming under constant temperature significantly reduced the growth rate but significantly increased the cellular elemental contents and sinking rate. However, warming significantly reduced cellular particulate organic carbon (POC) content, biogenic silica (BSi) content, and the sinking rate, while increasing the protein content to cope with thermal stress under temperature fluctuation. The effects of temperature fluctuation were dependent on the average temperature: at low average temperatures, temperature fluctuation increased cellular POC, BSi, POC productivity, and sinking rates, whereas at high average temperatures, these parameters were decreased significantly. For Nitzschia closterium f. minutissima, warming under both constant and fluctuated temperatures significantly increased the POC, particulate organic nitrogen (PON), and POP quotas. The interaction between warming and temperature fluctuation had antagonistic effects on most parameters examined for Thalassiosira sp., whereas it had synergistic effects on the physiological parameters of Nitzschia closterium f. minutissima. Overall, Nitzschia closterium f. minutissima exhibited stronger tolerance to warming and temperature fluctuation, suggesting species-specific responses of diatoms to warming and temperature fluctuations. These findings highlight the important yet often underestimated influence of temperature fluctuation on the physiology of marine diatoms in the context of global warming, thus having implications for a further understanding of biogeochemical feedbacks.</p

A Look at the Deadly Shark Attack on an Israeli Diver off the Mediterranean Coast of Hadera, Palestine

The Mediterranean Sea is home to a considerable number of shark species, some of which have posed a threat to humans. The hot waters discharged from the Hadera (Orot Rabin) power plant in northwestern Palestine attract schools of two large coastal shark species: Dusky Sharks (Carcharhinus obscurus Lesueur, 1818) and Sandbar Sharks (Carcharhinus plumbeus Nardo, 1827) every year from November to May. On Monday, April 21, 2025, a 45-year-old Israeli diver was fatally attacked by sharks off the Mediterranean coast of Hadera. The present descriptive study aims to shed light on this rare deadly incident. The study relied on collecting the necessary data through monitoring websites, news, and social media platforms. The Mediterranean coast of Hadera is characterized by a fascinating phenomenon that attracts many beachgoers, as they approach the shallow and warm waters dominated by predatory sharks. Several possible reasons for the shark attack on the Israeli diver have been listed, including the diver\u27s attempt to feed the shark dead fish for filming, the smell of bleeding fish the diver may have been carrying on his belt, mistaken identity of the sharks, the shark\u27s ability to detect the diver\u27s subtle electrical impulses, the diver\u27s possible sudden movements, loud noises, and frantic swimming that attracted the sharks, behavioral changes in the sharks due to human harassment, curiosity and confusion of the shark, hunger and starvation the sharks may have been suffering from, etc. The incident received unprecedented media coverage locally, regionally, and internationally, and sparked widespread interaction on social media platforms. Many Arab posts praised the shark for carrying out the attack, amid the fierce, destructive, and bloody war Israel has been waging against the Gazans since October 7, 2023. To prevent this incident from happening again, there is a need to manage the Mediterranean coast of Hadera in a way that is safe for humans and sharks

Rare mutations in N-methyl-D-aspartate glutamate receptors in autism spectrum disorders and schizophrenia

Pharmacological, genetic and expression studies implicate N-methyl-D-aspartate (NMDA) receptor hypofunction in schizophrenia (SCZ). Similarly, several lines of evidence suggest that autism spectrum disorders (ASD) could be due to an imbalance between excitatory and inhibitory neurotransmission. As part of a project aimed at exploring rare and/or de novo mutations in neurodevelopmental disorders, we have sequenced the seven genes encoding for NMDA receptor subunits (NMDARs) in a large cohort of individuals affected with SCZ or ASD (n=429 and 428, respectively), parents of these subjects and controls (n=568). Here, we identified two de novo mutations in patients with sporadic SCZ in GRIN2A and one de novo mutation in GRIN2B in a patient with ASD. Truncating mutations in GRIN2C, GRIN3A and GRIN3B were identified in both subjects and controls, but no truncating mutations were found in the GRIN1, GRIN2A, GRIN2B and GRIN2D genes, both in patients and controls, suggesting that these subunits are critical for neurodevelopment. The present results support the hypothesis that rare de novo mutations in GRIN2A or GRIN2B can be associated with cases of sporadic SCZ or ASD, just as it has recently been described for the related neurodevelopmental disease intellectual disability. The influence of genetic variants appears different, depending on NMDAR subunits. Functional compensation could occur to counteract the loss of one allele in GRIN2C and GRIN3 family genes, whereas GRIN1, GRIN2A, GRIN2B and GRIN2D appear instrumental to normal brain development and function

{P4Consist}: {T}oward Consistent {P4 SDNs}

The prevailing wisdom is that a software-defined network (SDN) operates under the premise that the logically centralized control plane has an accurate representation of the actual data plane state. Unfortunately, bugs, misconfigurations, faults or attacks can introduce inconsistencies between the network control and the data plane that can undermine the correct operation at runtime. Through our experiments, we realize that P4 SDNs are no exception, and are prone to similar problems. With the aim to verify the control-data plane inconsistency, we present the design and implementation of P4Consist, a system to detect the inconsistency between control and data plane in P4 SDNs. P4Consist generates active probe-based traffic continuously or periodically as an input to the P4 SDNs to check whether the actual behavior on the data plane corresponds to the expected control plane behavior. In P4Consist, the control plane and the data plane generate independent reports which are later, compared to verify the control-data plane consistency. The previous works in the field of monitoring and verification mostly aim to test the P4 programs through static analysis and thus, are insufficient to verify the network consistency at runtime. Experiments with our prototype implementation of P4Consist are promising and show that P4Consist can verify the control-data plane consistency in the complex datacenter 4-ary fat-tree (20 switches) and multipath grid (4, 9 and 16 switches) topologies with 60k rules per switch within a minimum time of 4 minutes. At the same time, P4Consist scales to multiple source-destination pairs to detect control-data plane inconsistency

Potentiel pigmentaire de diverses micro-algues isolées à partir des eaux continentales et leurs applications.

Nowadays there is an increasing demand for microalgal natural products, such as pigments, colorants, antioxidants and vitamins, for commercial use in the food and feed industry as well as in the pharmaceutical, nutraceutical and cosmetic sectors. Thereby, in order to select candidate strains with interesting accumulation levels of pigments (phycobiliproteins, carotenoids, chlorophylls) as valuable molecules, investigations were carried out and focused on 11 inland water microalgal strains isolated from different aquatic habitats. Ten strains belonged to cyanobacteria (Oscillatoriales, Nostocales and Chroococcales) and one to Chlorophyceae (Chlamydomonadales). Results showed that the cyanobacterium Cylindrospermopsis raciborskii, was found to be a very rich natural reservoir of C-phycocyanin (PC) with an amount reaching to 2.87 mg/ml. This level is tenfolds higher than the other two phycobiliprotein groups combined (Allophycocyanin and Phycoerythrin) and about two-folds higher compared with the PC amount in all the 10other strains together. This result is of particular interest for the therapeutic and pharmacological fields given the extremely health beneficial properties attributed to this phycobiliproteins group including anticancer, anti-inflammatory, neuroprotective and hepatoprotective effects as highlighted in many studies. On the other hand, results also indicated that the unicellular green microalgae, Dunaliella sp., was the top producer strain of four among the pigments analyzed in the present study (Allophycocyanin, total carotenoids as well as the two forms of chlorophyll a and b). This strain represents, thus, an excellent source of these very valuable pigments regarding their role in the prevention of numerous chronic and degenerative diseases such as cardiovascular diseases, diabetes, osteoporosis and several types of cancer (Lung, prostate, colon, breast, gastrointestinal, cervical, ovarian and pancreatic cancers) as proved in several epidemiological studies.De nos jours, il existe une demande croissante pour les produits naturels issus des microalgues comme les pigments, les colorants, les antioxydants et les vitamines en vue d’un usage commercial en industrie alimentaire ainsi que dans les secteurs pharmaceutique, nutraceutique et cosmétique. Dans ce contexte, des investigations ont été menées sur 11 souches de microalgues isolées à partir de différents habitats aquatiques afin d’identifier et de sélectionner les souches présentant des niveaux intéressants de production et d'accumulation des pigments naturels (phycobiliprotéines, caroténoïdes, chlorophylles) en tant que molécules à haute valeur ajoutée. Parmi ces souches, dix appartiennent au phylum des cyanobactéries (Oscillatoriales, Nostocales et Chroococcales) et une à la classe des Chlorophyceae (Chlamydomonadales). Les résultats ont montré que la cyanobactérie Cylindrospermopsis raciborskii se révélait être un réservoir naturel très riche en C-phycocyanine (PC) avec une teneur atteignant 2,87 mg/ml, soit dix fois plus élevée que celles de l’allophycocyanine et de la phycoérythrine de la même souche. Elle présente également une teneur deux fois plus élevée que celles des 10 autres souches investiguées. Ce résultat présente un intérêt particulier pour les domaines thérapeutiques et pharmaceutiques. En effet ce groupe de phycobiliprotéines présente des propriétés extrêmement bénéfiques pour la santé y compris leurs effets anticancéreux, anti-inflammatoires, neuroprotecteurs et hépatoprotecteurs tels que mis en évidence dans de nombreuses études. D'autre part, les résultats ont également indiqué que la microalgue verte unicellulaire, Dunaliella sp., était la souche la plus productrice de quatre parmi l’ensemble des pigments analysés dans la présente étude (allophycocyanine, caroténoïdes et les deux formes de chlorophylle a et b). Cette souche représente une excellente source de ces pigments très précieux vu leur rôle dans la prévention de nombreuses maladies chroniques et dégénératives telles que les maladies cardiovasculaires, le diabète, l'ostéoporose ainsi que plusieurs types de cancer (poumon, prostate, côlon, sein, col de l'utérus, ovaire, pancréas) comme ça était prouvé dans plusieurs études épidémiologiques.Publishe

Alexandrium pacificum Litaker sp. nov. (Group IV) : resting cyst distribution and toxin profile of vegetative cells in Bizerte Lagoon (Tunisia, Southern Mediterranean Sea)

A high spatial resolution sampling of Alexandrium pacificum cysts, along with sediment characteristics (% H2O, % organic matter (OM), granulometry), vegetative cell abundance and environmental factors were investigated at 123 study stations in Bizerte Lagoon (Tunisia). Morphological examination and ribotyping of cells obtained from a culture called ABZ1 obtained from a cyst isolated in lagoon sediment confirmed that the species was A. pacificum. The toxin profile from the ABZ1 culture harvested during exponential growth phase was simple and composed of the N-sulfocarbamoyl toxins C1 (9.82 pg toxin cell(-1)), the GTX6 (3.26 pg toxin cell(-1)) and the carbamoyl toxin Neo-STX (0.38 pg toxin cell(-1)).The latter represented only 2.8% of the total toxins in this strain. High abundance of A. pacificum cysts correlated with enhanced percentages of water and organic matter in the sediment. In addition, sediment fractions of less than 63 mu m were examined as a favorable potential seedbed for initiation of future blooms and outbreaks of A. pacificum in the lagoon. A significant difference in the cyst distribution pattern was recorded among the lagoon's different zones, with the higher cyst abundance occurring in the inner waters. Also, no correlation due to the specific hydrodynamics of the lagoon was observed in the spatial distribution of A. pacificurn cysts and vegetative cells