Stress Biomarkers in the Giant Manta Mobula birostris Associated to Tourism in the Revillagigedo National Park, Mexico

A constant increase in dive tourism over the past years in the Revillagigedo National Park, Mexico, could result in a stressful scenario for giant mantas (Mobula birostris). The purpose of this study was to determine the degree of oxidative stress in terms of changes in catalase units (CAT) and muscle glycogen concentration in this species during two periods of different tourism intensity in this protected area. A total of 21 muscle biopsies were collected in March (peak tourism) and November (lower tourism), 2019. Stress biomarkers were analysed by commercial kits from the company Cayman Chemical. Oxidative stress (catalase activity) was significantly higher during the period with lower tourism (p = 0.002), compared to the period with more tourism, suggesting the presence of the general adaptation syndrome. In males, there was a significant difference (p = 0.0005) in oxidative stress between periods of different tourism intensity, suggesting that the reproductive season may be a stressor. Morphotypes showed different oxidative stress (p = 0.031);however, the reason is unknown. No statistical differences were detected in glycogen concentrations between the tourism periods (p = 0.123), probably because this polysaccharide is not a proper indicator of chronic stress in giant mantas. Based on these findings, giant mantas may have an adequate response in terms of oxidative stress due to an increase in tourism;however the observed increase in catalase suggests that it is within the tolerance range of these organisms.

贵州关岭地区中晚三叠世法郎组中的软骨鱼类微体化石新材料

软骨鱼类的微体化石具有区域甚至全球性的地层对比潜力 ,还可以用于有机成熟度的分析。贵州关岭中晚三叠世法郎组产数量丰富、类型繁多的软骨鱼类微体化石 ,本文按照形态分类系统 ,对其进行了分类和描述。

中国海洋鱼类单殖吸虫研究XXV.单杯科二新记录种

记述采自广东汕尾软骨鱼类鳃上的2种单杯科单殖吸虫:三睾单杯虫(Monocotyle tritestis Young,1967)和凯西单杯虫(Monocotyle caseyae Chisholm&Whittington,2005).所获的三睾单杯虫标本与YOUNG(1967)的原始描述基本一致,但中央大钩的长度、后吸器脊片的形状略有不同;凯西单杯虫标本与CHISHOLM&WHITTINGTON(2005)的原始描述基本相同,但虫体后部的6个附加结构未见.三睾单杯虫和凯西单杯虫均为我国新记录种,赤魟和尖吻魟分别为其宿主新记录.

Oldest Asian Record of Snapping Shrimps(Malacostraca:Alpheidae)from the Kutch Basin,Western India and Associated Biota:Biostratigraphic,Paleoenvironmental and Paleoecological Significance

The oldest Asian record of alpheid shrimps,assigned to genus Alpheus,based on snapping claw fingertips from the Miocene Khari Nadi Formation in the Kutch Basin,western India reported herein,extends the fossil record of the family Alpheidae from Asia by~22 million years.An early Miocene(Aquitanian)age is estimated based on the associated assemblage of calcareous nannofossils,Sphenolithus disbelemnos,Cyclicargolithus floridanus,and Reticulofenestra haqii.The co-occurring microbiota includes bony fish otolith remains,identified as“genus Gobiidarum”,isolated teeth of Dasyatis rays,Sphyrna sharks,and teleosts,ctenoid and placoid scales,ostracods,belonging to the genera Paractinocythereis,Alocopocythere,Ruggieria,Aglaiocypris,Bairdoppilata,and echinoid spines.Taken together,the microfossil assemblage and data from chemical analyses using Energy Dispersive Spectroscopy,X-Ray Diffraction and Wavelength Dispersive X-Ray Fluorescence of host and associated lithologies suggests prevalence of a shallow(neritic)to coastal marine(intertidal)depositional paleoenvironment.The present investigation also provides the oldest fossil evidence on the co-occurrence of Alpheus and gobiids(based on otoliths)that strongly advocates that the mutualistic association between these animal groups had developed by the Aquitanian.

Living with high concentrations of urea: They can!

Marine elasmobranchs maintain their body fluid isoosmotic or slightly hyperosmotic to the external medium by the retention of large urea concentrations. This review focuses on the strategies adopted by these fishes to maintain a large outwardly direct concentration gradient of this osmolyte minimizing the loss across the main interfaces between body fluid and the external medium such as the gills, the kidney and the rectal gland, thus reducing the cost of making urea. The high plasma osmolarity, mainly main-tained by urea retention, is a challenge to volume homeostasis when fish move from seawater to water with a low salinity, since the high water permeability of branchial epithelium would cause a net flux of water into the animal. Since the renal regulation of urea retention in habitat with different salinities is crucial for the osmotic homeostasis of these species, the regulation of the activity and/or the expression of urea trans porters in renal tubules will be also discussed. In addition attention will be paid on the urea– methylamine system involved in maintaining the stability and functioning of many proteins since it is known that the high urea concentration found in marine elasmobranch fish, similar only to that found in mammalian kidney, has a destabilizing effect on many macromolecules and inhibits functions such as ligand binding.

詹氏魟刺粗提物的药理学研究及话性成分的光谱表征(英文)

AIM:Dasyatis jenkinsii is used traditionally to treat inflammatory complaints and arthritis by the fisherman community and local population.The present study was designed to scientifically investigate the traditional practice through the analgesic,anti-inflammatory,and organ toxicity studies and characterization of bioactive compounds of crude extracts of D.jenkinsii.METHOD: Solvent extract of homogenized fresh fish was prepared using petroleum ether and diethyl ether.The chemical and spectral analyses of extracts were carried out using FT-IR and GC-MS.Analgesic and anti-inflammatory activities were assessed by hot plate,tail clip,and carrageenan induced rat paw edema methods.The organ toxicity of each extract was assessed on brain,liver,and kidney of mice.RESULTS:The IR spectrum indicated the presence of aromatic and aliphatic compounds.GC-MS analysis revealed the presence of 1-(4-carboxy)phenylnona-2,5-diene and 3-hydroxymono-glyceryl hydrogen phthalate in the petroleum ether extract and carboxyl serine,dihydrotryptophan,and indolyl carboxylic acid in the diethyl ether extract.Both extracts showed significant analgesic and anti-inflammatory effects in all the methods tested.The vital organs of the test animals were not affected by the crude extracts significantly.CONCLUSIONS:The presence of biologically active compounds in the crude extracts with analgesic and anti-inflammatory properties justifies the traditional knowledge and paves the way for isolation of these compounds for further experimentation.

Cerebrovascularβ-dystroglycan immunoreactivity in vertebrates:not detected in anurans and in the teleosts Ostariophysi and Euteleostei

The aim of the present paper was to check for the presence of cerebrovascular dystroglycan in vertebrates,because dystroglycan,which is localized in the vascular astroglial end-feet,has a pivotal function in glio-vascular connections.In mammalian brains,the immunoreactivity ofβ-dystroglycan subunit delineates the vessels.The results of the present study demonstrate similar patterns in other vertebrates,except for anurans and the teleost groups Ostariophysi and Euteleostei.In this study,we investigated 1 or 2 representative species of the main groups of Chondrichthyes,teleost and non-teleost ray-finned fishes,urodeles,anurans,and reptiles.We also investigated 5 mammalian and 3 bird species.Animals were obtained from breeders or fishermen.The presence ofβ-dystroglycan was investigated immunohistochemically in free-floating sections.Pre-embedding electron microscopical immunohistochemistry on Heterodontus japonicus shark brains demonstrated that in Elasmobranchii,β-dystroglycan is also localized in the perivascular glial end-feet despite the different construction of their blood-brain barrier.The results indicated that the cerebrovascularβ-dystroglycan immunoreactivity disappeared separately in anurans,and in teleosts,in the latter group before its division to Ostariophysi and Euteleostei.Immunohistochemistry in muscles and western blots from brain homogenates,however,detected the presence ofβ-dystroglycan,even in anurans and all teleosts.A possible explanation is that in the glial end-feet,β-dystroglycan is masked in these animals,or disappeared during adaptation to the freshwater habitat.

Morphologic features of the cerebellum of the Atlantic stingray, and their possible evolutionary significance

The morphology of the cerebellar corpus in cartilaginous fishes varies from a smooth,relatively simple structure to a complex,multilobed structure.Atlantic stingrays possess a trilobed corpus that includes an anterior lobe,divided into rostral and caudal lobules,and a posterior lobe.The corpus in this stingray is assymetrical.This asymmetry was examined in the stingray population of Galveston Bay.In 49%of the animals the axis of the caudal lobule was right of the midline,in 27%it was across the midline,and in 24%it was to the left.This variation is not related to size,sex,or an asymmetry in the cranial volume,but might reflect a variation in the cerebellar developmental program.To gain insight into the factors that have driven cerebellar hypertrophy in cartilaginous fishes,the neural connections of the lobules of the cerebellum of the Atlantic stingray were examined using biotinylated dextrans.It was found that,for the most part,the stingray cerebellum receives inputs from the same diencephalic and brainstem nuclei as in cartilaginous fishes with a bilobed cerebellum.However,in stingrays there is greater segregation of inputs.The anterior lobe rostral lobule receives inputs from the accessory optic nuclei,the caudal lobule receives inputs from trigeminal and octavolateral nuclei,and the posterior lobe receives inputs from the spinal cord.The rostral lobule and posterior lobe also receive input from midbrain nuclei that do not appear to be present in carti-laginous fishes with a morphologically simple corpus.Therefore,it is proposed that the complex hypertrophy of the corpus in stingrays might result from a combination of functional specialization of the lobes,and the acquisition of new inputs.

Effects of fasting and refeeding on intestinal cell proliferation and apoptosis in hammerhead shark(Sphyrna lewini)

Objective:To examine the effects of fasting and refeeding on intestinal cell proliferation and apoptosis in an opportunistic predator,hammerhead shark(Sphyrna lewini)of elasmobranch fishes which are among the earliest known extant groups of vertebrates to have the valvular intestine ty pical for the primitive species.Methods:Animals were euthanized after 5-10 d of fasting or feeding,or after 10-day fasting and 5-day refeeding.Intestinal apoptosis and cell proliferation were assessed by using oligonucleotide detection assay,terminal deoxynucleotidyl transferase dUTP nick end labeling staining,and immunohistochemistry of proliferating cells nuclear antigen.Results:Plasma levels of cholesterol and glucose were reduced by fasting.Intestinal apoptosis generally decreased during fasting.Numerous apoptotic cells were observed around the tips of the villi,primarily in the epithelium in the fed sharks,whereas fewer labeled nuclei were detected in the epithelium of fasted sharks.Reeding returned intestinal apoptosis to the level in the fed sharks.Proliferating cells were observed in the epithelium around the troughs of the villi and greater in number in fed sharks,whereas fewer labeled nuclei were detected in fasted sharks.Conclusions:The cell turnover is modified in both intestinal epithelia of the shark and the murines by fasting/feeding,but in opposite directions.The difference may reflct the feeding ecology of the elasmobranchs,primitive intermittent feeders.

贵州西南部中三叠世拉丁期软骨鱼类鱼鳞化石(英文)

本文报道产自贵州西南部中三叠世拉丁期晚期竹杆坡组的软骨鱼类鱼鳞化石,这些化石归属于4属6种,其中有3新种,即Rugosicoronaci rcacarina sp.nov.,Fragilicorona wanlantricuspis sp.nov.和Glabrisubcorona triridgecorona sp.nov.。并将中国西南部与加拿大东南部相当地层中软骨鱼类微体化石进行了初步对比。