El solapamiento de la dieta del carite estriado Indo–Pacífico Scomberomorus commerson (Lac., 1802) y del pez sable Trichiurus lepturus (L., 1758) en la costa mediterránea egipcia

The immigrant S. commerson (Lac., 1802) represents more than 2% of the total Egyptian catch and its distribution stretches from East to West along the Egyptian Mediterranean coast. The feeding habits of T. lepturus and S. commerson were investigated through stomach content analysis of specimens collected from Abu Qir Bay (Egypt) on a seasonal basis from November 1999 to January 2001 using daytime purse seines. The food content range of T. lepturus was wide, including Engraulis encrasicolus, Gobius spp., Sardinella aurita, Sardina pilchardus, fish eggs, amphipods, copepods and shrimps. The main diet constituents of S. commerson included Engraulis encrasicolus, Sardinella aurita, Sardina pilchardus and shrimps. Seasonal variations of feeding activity indicated that food consumption was highest in spring to autumn for T. lepturus and in summer and autumn for S. commerson. The diet overlap in terms of number and weight between the two species was high. Food composition was related to fish size in both examined fishes. Small T. lepturus (less than 30 cm) fed mainly on crustaceans, while larger samples (more than 59 cm) fed only on fishes. Teleosts were the most important food item for S. commerson of all sizes, while this species became piscivorous when larger than 40 cm in length. Key words: Diet and trophic level, Trichiurus lepturus, Scomberomorus commerson, Egyptian coast.La especie inmigrante S. commerson (Lac., 1802) constituye más del 2% de las capturas egipcias totales y su área de distribuciónse extiende de este a oeste a lo largo de la costa mediterránea egipcia. Se investigaron los hábitos alimentarios de T. lepturus y S. commerson a través del análisis de los contenidos estomacales de los ejemplares recogidos en la bahía de Abu Qir (Egipto) siguiendo una pauta estacional desde noviembre de 1999 a enero del 2001, utilizando jábegas diurnas. La variedad del contenido estomacal de T. lepturus era amplia, incluyendo a Engraulis encrasicolus, Gobius spp., Sardinella aurita, Sardina pilchardus, huevas de pez, anfípodos, copépodos y decápodos. La dieta principal de S. commerson incluía Engraulis encrasicolus, Sardinella aurita, Sardina pilchardus y decápodos. Las variaciones estacionales de la actividad alimentaria indicaban que el mayor grado de consumo de alimentos se daba de primavera a otoño en T. lepturus, y de verano a otoño en S. commerson. El solapamiento de la dieta de las dos especies, en términos de número y peso, era grande. En ambas especies examinadas se detectaron cambios en la composición del alimento, en función de la talla de los peces. Los T. lepturus de tallas pequeñas (menos de 30 cm) se alimentaban principalmente de crustáceos, mientras que los de tallas grandes (de más de 59 cm) se alimentaban sólo de peces. En todos los grupos de tallas de S. commerson, las presas principales eran los teleósteos, aunque esta especie se vuelve totalmente piscívora al superar el tamaño de 40 cm. Palabras clave: Dieta y nivel trófico, Trichiurus lepturus, Scomberomorus commerson, Costa egipcia

Qualité pastorale des ressources herbagères de la réserve de biosphère du Ferlo (Nord-Sénégal)

La strate herbacée des phytocénoses sahéliennes joue un rôle de grande importance dans l’alimentation du bétail. Ainsi, la connaissance de la production de fourrage « qualifié » permet de mieux suivre le fonctionnement des groupements herbacés. Cette étude évalue la production et apprécie la qualité pastorale des herbages de la réserve de biosphère du Ferlo (Nord Sénégal). Un inventaire floristique de la végétation herbacée a été effectué sur 201 placettes en zone tampon et en zone de transition de la réserve de biosphère. Le cortège floristique, le recouvrement et la contribution spécifique de la strate herbacée ont été établis. La production de phytomasse herbacée au maximum de la végétation par la récolte intégrale est estimée à 3,3 tonnes de MS/ha. L’indice global de qualité (IGQ) des parcours de la réserve de biosphère est de 56,4%. Huit espèces (Schoenefeldia gracilis Kunth., Eragrostis tremula Hochst., Pennisetum pedicellatum Trin., Andropogon gayanus Kunth., Zornia glochidiata Reichb. Ex DC., Andropogon pseudapricus Stapf., Schizychirium exile Stapf. et Senna mimosoides L.) déterminent à 91% la valeur pastorale des herbages. La production de fourrage « qualifié » est estimée à 1,86 tonne de MS/ha et la capacité de charge à 0,41 UBT/ha/an.Mots clés: fourrage herbager - valeur pastorale - capacité de charg

Cross-Sectional Comparison of Behavioral Risk Factors for HIV/HCV in People Who Inject Drugs (PWID) in Egypt

Background Egypt has the greatest HCV prevalence worldwide at 15% and a concentrated HIV epidemic in male people who inject drugs (PWID) at 6.8%, who are at a high risk for HCV infection as well. Injection drug use is criminalized in Egypt, and there is limited availability of harm reduction programs. Drug-use and sexual risk behaviors between PWID and the general population have not been studied there. Methods To address this gap, a cross-sectional HIV/HCV epidemiological study of 632 consenting injection drug users in Cairo and Alexandria was conducted. Bivariate logistic regression analysis was done to evaluate the associations between HIV/HCV and needle sharing or sexual practices using SAS 9.4. Results 10.6% (63/ 604) of the study population tested positive for HIV and 61.5% (384/624) tested positive for HCV. Sharing needles with more than 10 people was associated with HIV and HCV infection (OR=3.65, p-val=0.001; OR=2.05, p-val=0.02, respectably). Age was associated with both HIV and HCV (p-val=0.03 and Conclusions The results indicate that the growing epidemic among PWID in Egypt may place the general population at risk for HIV and HCV primarily through sexual contact. In Russia, repressive policies toward PWID allowed HIV to spread to the general population at the start of the epidemic in 2000. Now, 48% of HIV is heterosexually transmitted in Russia and the country contributes \u3e80% of the HIV cases in Eastern Europe and Central Asia. In response to the epidemic, even more punitive laws and regulations were introduced in Russia, and their HIV prevalence has seen a 49% increase between 2005 and 2015. A similar trajectory can be expected for Egypt if preventative measures are not taken. Common-sense harm reduction programs like clean needle exchanges and decriminalization of injection drug use should be part of a comprehensive plan to control the spread of HIV and HCV in Egypt

Prime movers : mechanochemistry of mitotic kinesins

Mitotic spindles are self-organizing protein machines that harness teams of multiple force generators to drive chromosome segregation. Kinesins are key members of these force-generating teams. Different kinesins walk directionally along dynamic microtubules, anchor, crosslink, align and sort microtubules into polarized bundles, and influence microtubule dynamics by interacting with microtubule tips. The mechanochemical mechanisms of these kinesins are specialized to enable each type to make a specific contribution to spindle self-organization and chromosome segregation

Small molecules targeted to the microtubule–Hec1 interaction inhibit cancer cell growth through microtubule stabilization

Highly expressed in cancer protein 1 (Hec1) is a subunit of the kinetochore (KT)-associated Ndc80 complex, which ensures proper segregation of sister chromatids at mitosis by mediating the interaction between KTs and microtubules (MTs). HEC1 mRNA and protein are highly expressed in many malignancies as part of a signature of chromosome instability. These properties render Hec1 a promising molecular target for developing therapeutic drugs that exert their anticancer activities by producing massive chromosome aneuploidy. A virtual screening study aimed at identifying small molecules able to bind at the Hec1–MT interaction domain identified one positive hit compound and two analogs of the hit with high cytotoxic, pro-apoptotic and anti-mitotic activities. The most cytotoxic analog (SM15) was shown to produce chromosome segregation defects in cancer cells by inhibiting the correction of erroneous KT–MT interactions. Live cell imaging of treated cells demonstrated that mitotic arrest and segregation abnormalities lead to cell death through mitotic catastrophe and that cell death occurred also from interphase. Importantly, SM15 was shown to be more effective in inducing apoptotic cell death in cancer cells as compared to normal ones and effectively reduced tumor growth in a mouse xenograft model. Mechanistically, cold-induced MT depolymerization experiments demonstrated a hyper-stabilization of both mitotic and interphase MTs. Molecular dynamics simulations corroborate this finding by showing that SM15 can bind the MT surface independently from Hec1 and acts as a stabilizer of both MTs and KT–MT interactions. Overall, our studies represent a clear proof of principle that MT-Hec1-interacting compounds may represent novel powerful anticancer agents

Clonal Hematopoiesis and Blood-Cancer Risk Inferred from Blood DNA Sequence

Background Cancers arise from multiple acquired mutations, which presumably occur over many years. Early stages in cancer development might be present years before cancers become clinically apparent. Methods We analyzed data from whole-exome sequencing of DNA in peripheral-blood cells from 12,380 persons, unselected for cancer or hematologic phenotypes. We identified somatic mutations on the basis of unusual allelic fractions. We used data from Swedish national patient registers to follow health outcomes for 2 to 7 years after DNA sampling. Results Clonal hematopoiesis with somatic mutations was observed in 10% of persons older than 65 years of age but in only 1% of those younger than 50 years of age. Detectable clonal expansions most frequently involved somatic mutations in three genes (DNMT3A, ASXL1, and TET2) that have previously been implicated in hematologic cancers. Clonal hematopoiesis was a strong risk factor for subsequent hematologic cancer (hazard ratio, 12.9; 95% confidence interval, 5.8 to 28.7). Approximately 42% of hematologic cancers in this cohort arose in persons who had clonality at the time of DNA sampling, more than 6 months before a first diagnosis of cancer. Analysis of bone marrow–biopsy specimens obtained from two patients at the time of diagnosis of acute myeloid leukemia revealed that their cancers arose from the earlier clones. Conclusions Clonal hematopoiesis with somatic mutations is readily detected by means of DNA sequencing, is increasingly common as people age, and is associated with increased risks of hematologic cancer and death. A subset of the genes that are mutated in patients with myeloid cancers is frequently mutated in apparently healthy persons; these mutations may represent characteristic early events in the development of hematologic cancers. (Funded by the National Human Genome Research Institute and others.)National Human Genome Research Institute (U.S.) (Grant U54 HG003067)National Human Genome Research Institute (U.S.) (Grant R01 HG006855)Stanley Center for Psychiatric ResearchAlexander and Margaret Stewart TrustNational Institute of Mental Health (U.S.) (Grant R01 MH 077139)National Institute of Mental Health (U.S.) (Grant RC2 MH089905)Sylvan C. Herman Foundatio

Karyotypic Determinants of Chromosome Instability in Aneuploid Budding Yeast

Recent studies in cancer cells and budding yeast demonstrated that aneuploidy, the state of having abnormal chromosome numbers, correlates with elevated chromosome instability (CIN), i.e. the propensity of gaining and losing chromosomes at a high frequency. Here we have investigated ploidy- and chromosome-specific determinants underlying aneuploidy-induced CIN by observing karyotype dynamics in fully isogenic aneuploid yeast strains with ploidies between 1N and 2N obtained through a random meiotic process. The aneuploid strains exhibited various levels of whole-chromosome instability (i.e. chromosome gains and losses). CIN correlates with cellular ploidy in an unexpected way: cells with a chromosomal content close to the haploid state are significantly more stable than cells displaying an apparent ploidy between 1.5 and 2N. We propose that the capacity for accurate chromosome segregation by the mitotic system does not scale continuously with an increasing number of chromosomes, but may occur via discrete steps each time a full set of chromosomes is added to the genome. On top of such general ploidy-related effect, CIN is also associated with the presence of specific aneuploid chromosomes as well as dosage imbalance between specific chromosome pairs. Our findings potentially help reconcile the divide between gene-centric versus genome-centric theories in cancer evolution

Induction of APOBEC3 Exacerbates DNA Replication Stress and Chromosomal Instability in Early Breast and Lung Cancer Evolution

APOBEC3 enzymes are cytosine deaminases implicated in cancer. Precisely when APOBEC3 expression is induced during cancer development remains to be defined. Here we show that specific APOBEC3 genes are upregulated in breast DCIS, and in pre-invasive lung cancer lesions coincident with cellular proliferation. We observe evidence of APOBEC3-mediated subclonal mutagenesis propagated from TRACERx pre-invasive to invasive NSCLC lesions. We find that APOBEC3B exacerbates DNA replication stress and chromosomal instability through incomplete replication of genomic DNA, manifested by accumulation of mitotic ultrafine bridges and 53BP1 nuclear bodies in the G1 phase of the cell cycle. Analysis of TRACERx NSCLC clinical samples and mouse lung cancer models, revealed APOBEC3B expression driving replication stress and chromosome missegregation. We propose that APOBEC3 is functionally implicated in the onset of chromosomal instability and somatic mutational heterogeneity in pre-invasive disease, providing fuel for selection early in cancer evolution

Comparative Oncogenomic Analysis of Copy Number Alterations in Human and Zebrafish Tumors Enables Cancer Driver Discovery

The identification of cancer drivers is a major goal of current cancer research. Finding driver genes within large chromosomal events is especially challenging because such alterations encompass many genes. Previously, we demonstrated that zebrafish malignant peripheral nerve sheath tumors (MPNSTs) are highly aneuploid, much like human tumors. In this study, we examined 147 zebrafish MPNSTs by massively parallel sequencing and identified both large and focal copy number alterations (CNAs). Given the low degree of conserved synteny between fish and mammals, we reasoned that comparative analyses of CNAs from fish versus human MPNSTs would enable elimination of a large proportion of passenger mutations, especially on large CNAs. We established a list of orthologous genes between human and zebrafish, which includes approximately two-thirds of human protein-coding genes. For the subset of these genes found in human MPNST CNAs, only one quarter of their orthologues were co-gained or co-lost in zebrafish, dramatically narrowing the list of candidate cancer drivers for both focal and large CNAs. We conclude that zebrafish-human comparative analysis represents a powerful, and broadly applicable, tool to enrich for evolutionarily conserved cancer drivers.Kathy and Curt Marble Cancer Research FundArthur C. MerrillNational Institutes of Health (U.S.) (Grant CA106416)National Institutes of Health (U.S.) (Grant ROI RR020833)National Institutes of Health (U.S.) (Grant 1F32GM095213-01