Pseudo-chromosome–length genome assembly for a deep-sea eel Ilyophis brunneus sheds light on the deep-sea adaptation

High hydrostatic pressure,low temperature,and scarce food supply are the major factors that limit the survival of vertebrates in extreme deep-sea environments.Here,we constructed a high-quality genome of the deep-sea Muddy arrowtooth eel(MAE,Ilyophis brunneus,captured below a depth of 3,500 m)by using Illumina,Pac Bio,and Hi-C sequencing.We compare it against those of shallow-water eel and other outgroups to explore the genetic basis that underlies the adaptive evolution to deep-sea biomes.The MAE genome was estimated to be 1.47 Gb and assembled into 14 pseudo-chromosomes.Phylogenetic analyses indicated that MAE diverged from its closely related shallow-sea species,European eel,~111.9 Mya and experienced a rapid evolution.The genome evolutionary analyses primarily revealed the following:(i)under high hydrostatic pressure,the positively selected gene TUBGCP3 and the expanded family MLC1 may improve the cytoskeleton stability;ACOX1 may enhance the fluidity of cell membrane and maintain transport activity;the expansion of ABCC12 gene family may enhance the integrity of DNA;(ii)positively selected HARS likely maintain the transcription ability at low temperatures;and(iii)energy metabolism under a food-limited environment may be increased by expanded and positively selected genes in AMPK and m TOR signaling pathways.

Clinical and pathological features of intracranial meningiomas in children:A retrospective analysis

BACKGROUND： The attack of meningiomas has sex and age differences. Previous studies indicated that children and adult patients had different clinical and pathological features. Due to the limitation of conditions and technique of diagnosis and treatment, some clinical and pathological features of meningiomas in children should be further recognized. OBJECTIVE： To summarize the clinical and pathological features in 15 children with intracranial meningiomas DESIGN ： A retrospective case analysis SETTING： The hospitals which the first author had been working inPARTICIPANTS ： Fifteen children with intracranial meningiomas were selected from the hospitals the frst author had been working in from June 1996 to June 2006. There were 9 boys and 6 girls, aged 1.8-15 years, with an average of 9.8 years. The duration from attack to diagnosis was 1 month to 2.5 years, with an average of 13 months. Inclusive criteria： （1） Clinically diagnosed, operated and confirmed pathologically; （2）≤ 15 years; （3） The children and their relatives were all informed and agree with the detection. METHOOS ： The clinical manifestations, imaging data, preoperative diagnosis and misdiagnosis, site and size of tumor, operative treatment and pathological data were retrospectively summarized. Thirteen of 15 children with intracranial meningiomas were followed up by means of reexamination for 1-8 years, and the postoperative recurrence were observed. MAIN OUTCOME MEASURES： Clinical manifestations, imaging data, preoperative diagnosis and misdiagnosis, site and size of tumor, operative treatment, pathological data, recurrence conditions of 1 to 8 years follow-up.RESULTS ： Thirteen of the 15 children with intracranial meningiomas were involved in the analysis of results, and 2 lost to the follow-up. （1） The main clinical manifestations at diagnosis were headache in 11 cases （73%, 11/15）, vomiting in 8 cases （53%, 8/15）, papilledema in 9 cases （60%, 9/15）, hypopsia in 6 cases （40%, 6115）, epilepsy in 5 cases （33%, 5/15）, hemiplegia in 4 cases （27%, 4/15）, cranial nerve damage in 4 cases （27%, 4/15）, instability of gait and incoordination in 2 cases, conscious disturbance in 3 cases, nystagmus in 2 cases and lump under scalp in 1 case. （2） Imaging examination： Most of tumor CT plain scans were slightly high-density imaging, most enhanced scanning appeared well-distributed enhancement and clear boundary. MRI examination observed the tumor appeared equal or long T1 or longer T2 abnormal mixed singles with clear boundary. Two cases had cystic lesion of tumor and 8 cases had pedtumor edema. Digital substraction angiography （DSA） observed that there obvious tumor staining and displacement of corresponding brain vessels due to compression in 2 cases. （3） Preoperative misdiagnosis： Six children （40%, 6/15） were misdiagnosed to have other diseases due to the untypical symptoms, including diseases of gastrointestinal tract in 3 cases, eye diseases in 2 cases, and encephalitis in I case. Most cases were diagnosed after CT or MRI scanning. （4） Sites and sizes of tumors： Tumor located at supratentonal parts in 13 cases （87%, 13/15）, including cerebral convexity in 7 cases （46.7%, 7/15）, intraventdcle in 2 cases （13.3%, 2/15）, cerebral parenchyma in 2 cases （13.3%, 2/15）, parafalx and parasagittal sinus in 2 cases respectively. Tumor located at infratentonal part in 2 cases （13.3%, 2/15）, which at cerebellar hemisphere and cerebellopontine angle respectively. The maximal diameter of tumor was 1.3-8.0 cm with an average of 4.6 cm. （5） Pathological types： The pathological examination reported that the meningioma was benign in 11 cases （73.3%, 11/15） and malignant in 4 cases （26.7%, 4/15）. Among the benign meningiomas, it was syncytial in 5 cases, fibrous in 4 cases, and transitional in 2 cases. （6） Treatments： All the menigiomas of children were resected, and 14 cases （93.3%, 14/15） had the tumor resected totally （Simpson grades Ⅰ -Ⅲ ）, including Simpson grade Ⅰ resection in 7 cases, grade Ⅱ in 4 cases, and grade Ⅲ in 3 cases. One case only underwent subtotal resection （Simpson Ⅳ ）, this case had invasive medial sphenoid ndge-diaphragma sellae meningiomas, the tumor grew towards cavernous sinus and antenor skull base, and wrapped ipsilateral internal carotid artery and optic nerve. No one died postoperatively. （7） Follow up and recurrence： Of the 15 children with meningiomas, 13 cases were followed up, 4 cases （31%, 4/13） recurred, including 1 case recurred at 1 year, which was malig- nant meningioma, another 3 cases recurred at 3.5, 5.5 and 7 years after operation respectively, which were benign meningiomas.CONCLUSION ： Meningiomas in children, most of which are benign, mostly locate at supratentonal part, hav ehigher incidence rate in boys than in girls, higher recurrence rate, untypical symptoms, and easy to be misdiagnosed. The tumors grow rapidly with shorter disease course.

New species of the giant deep-sea isopod genus Bathynomus(Crustacea,Isopoda,Cirolanidae)from Hainan Island,South China Sea

Several specimens of the giant deep-sea isopod genus Bathynomus were collected by a deep-sea lander at a depth of 898 m near Hainan Island in the northern South China Sea.After careful examination,this material and the specimens collected from the Gulf of Aden,north-western Indian Ocean,previously reported as Bathynomus sp.,were identified to be the same as a new species to the genus.Bathynomus jamesi sp.nov.can be distinguished from the congeners by:the distal margin of pleotelson with 11 or 13 short straight spines and central spine not bifid;uropodal endopod and exopod with distolateral corner slightly pronounced;clypeus with lateral margins concave;and antennal flagellum extending when extended posteriorly reaches the pereonite 3.In addition,Bathynomus jamesi sp.nov.is also supported by molecular analyses based on mitochondrial COI and 16S rRNA gene sequences.The distribution range of the new species includes the western Pacific and north-western Indian Ocean.

Geology, environment, and life in the deepest part of the world’s oceans

The hadal zone,mostly comprising of deep trenches and constituting of the deepest part of the world’s oceans,represents the least explored habitat but one of the last frontiers on our planet.The present scientific understanding of the hadal environment is still relatively rudimentary,particularly in comparison with that of shallower marine environments.In the last 30 years,continuous efforts have been launched in deepening our knowledge regarding the ecology of the hadal trench.However,the geological and environmental processes that potentially affect the sedimentary,geochemical and biological processes in hadal trenches have received less attention.Here,we review recent advances in the geology,biology,and environment of hadal trenches and offer a perspective of the hadal science involved therein.For the first time,we release highdefinition images taken by a new full-ocean-depth manned submersible Fendouzhe that reveal novel species with an unexpectedly high density,outcrops of mantle and basaltic rocks,and anthropogenic pollutants at the deepest point of the world’s ocean.We advocate that the hydration of the hadal lithosphere is a driving force that influences a variety of sedimentary,geochemical,and biological processes in the hadal trench.Hadal lithosphere might host the Earth’s deepest subsurface microbial ecosystem.Future research,combined with technological advances and international cooperation,should focus on establishing the intrinsic linkage of the geology,biology,and environment of the hadal trenches.