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Fish specimens (n=75) of A. arabicus were collected from the marine waters of Iraq at Khor al-Zubair. Collection was conducted in the period February–September 2019 at depth of 10–25 m. Relationships between fish length and otolith length, width and weight were calculated for the Arabian yellowfin seabream, Acanthopagrus arabicus using linear models. This study represents the first data available on the relationship of fish size and otolith size and weight for A. arabicus in the Arabian Gulf area. The various relationships between fish length otolith length, width and weight were calculated: Y = -1E – 0.06X2 + 0.0106X + 5.2628, Y = 4E – 06X2 + 0.0077X + 2.1834, and Y = 9E – 07X2 + 0.0013X – 0.191 respectively.

The human population is currently facing the third and possibly the worst pandemic caused by human coronaviruses (CoVs). The virus was first reported in Wuhan, China, on 31 December 2019 and spread within a short time to almost all countries of the world. Genome analysis of the early virus isolates has revealed high similarity with SARS-CoV and hence the new virus was officially named SARS-CoV-2. Since CoVs have the largest genome among all RNA viruses, they can adapt to many point mutation and recombination events; particularly in the spike gene, which enable these viruses to rapidly change and evolve in nature. CoVs are known to cross the species boundaries by using different cellular receptors. Both animal reservoir and intermediate host for SARS-CoV-2 are still unresolved and necessitate further investigation. In the current review, different aspects of SARS-CoV-2 biology and pathogenicity are discussed, including virus genetics and evolution, spike protein and its role in evolution and adaptation to novel hosts, and virus transmission and persistence in nature. In addition, the immune response developed during SARS-CoV-2 infection is demonstrated with special reference to the interplay between immune cells and their role in disease progression. We believe that the SARS-CoV-2 outbreak will not be the last and spillover of CoVs from bats will continue. Therefore, establishing intervention approaches to reduce the likelihood of future CoVs spillover from natural reservoirs is a priority.

Saccular otolith mass asymmetry is examined in three sparid fish species, Acanthopagrus bifasciatus, A. arabicus, and Sparidentex hasta collected from Khor Abdullah at the North Persian Gulf. This characteristic was computed as the disparity between the weight of the right and left otoliths divided by mean otolith weight in the three sparid species investigated. According to the previous cases obtained on another symmetrical fish species, the absolute value of x in these species does not determine by fish length and otolith growth ratio, while the absolute rate of otolith weight disparity is boosted with the fish length. The estimate of x was between -0.2 and +0.2. Otolith mass asymmetry can show some growth disorder of fish owing to environmental influence.

Bilateral asymmetry is presumed to reveal the developmental variability of the fish in polluted aquatic environments. In these habitats, high-level asymmetry develops, and these fish expend more energy to balance their growth than fish that are not under an impact. A total of 210 specimens of Acanthopagrus bifasciatus, A. latus and Sparidentex hasta were collected from the marine waters of Iraq in the northwest part of the Arabian Gulf. The asymmetry was calculated for the sagittal otolith characters of length and width. Otolith width has lower asymmetry than otolith length for the three sparid fish species investigated. An increase in the value of fluctuating asymmetry with fish length was observed. This could be a pertinent indicator of pollution in the habitat.

According to reports, the last comprehensive fish records from the Indus River were published in 1977. Although few recent studies have been conducted, they are limited to some confined localities, and hence there was a gap of comprehensive fish diversity analysis of the Indus River in the Sindh province section. Therefore, the present investigation was performed to describe the fish fauna of the Indus River from its northern to its southern extremities. In order to establish fish diversity and distribution, the study was accomplished from June 2016 to May 2017 covering 8 sampling locations across the river. A total of 44 fish species, belonging to 35 genera, included in 18 families, and 9 orders were recorded. Family Cyprinidae was the most specious with 13 species followed by Bagridae and Cichlidae with 4 species each, and Siluridae with3 species. Alpha Diversity Indices study showed that the ichthyofauna diversity of the River was not high in comparison with previous studies. Shannon’s index for the whole Indus River locations was 0.95 and the evenness index was 0.77. Sustained populations of exotic fish species were shown to have established in the Indus River.

In current investigations on the relationship of length and weight of 5 carps were presented, total 256 fish were caught between September 2016 and August 2017 from Keenjhar Lake District Thatta, Sindh. Cyprinus carpio were 77 out of which 50 males and 27 females, with total length ranging from 34.3 to 36.6 cm 33.7 to 37.4 cm respectively, Labeo rohita were 75, 45 males and 30 females with total length ranging from 32.0 to 39.0 cm, and 40.9 to 45.7cm respectively.Cirrhinus mrigala was 45 out of which 20 males and 25 females, with a total length ranging from 41.3to 43.2 cm, and 43.4 to 46.6 cm respectively. In case of Hypophthalmichthys molitrix the total number was 33 which of 15 males and 18 females with the total length ranging from 39.3 to 41.9 cm and 42.3 to 44.2 cm respectively and 26 were Catla catla 14 males and 12 females with total length ranging from 33.7 to 36.2 cm from 42.5 to 44.9 cm respectively.The length weight relationships andcorrelation of co efficient was analyzed for either sex separately. In the present studies values of b varied from 3.11 and 2.81 male and female of Cyprinus carpio, forLabeo rohita 2.79 and 2.65 respectively,3.94 and 2.87 male and female of Cirrhinus mrigalaof the b value of Hypophthalmichthys molitrix in male 2.85 and 2.65 in female for Catla catla in male and female 2.70 and 2.77.Calculated coefficient of condition in Cyprinus carpio found to be 1.04, 0.94 in male and female respectively, Labeo rohita 0.97, 1.17 for male and female respectively, in Cirrhinus mrigala found to be 1.07, 0.98 in male and female respectively, for Hypophthalmichthys molitrixand Catla catla 0.89, 0.91, 0.93, and 0.97male and female respectively. The studies reveled that Cirrhinus mrigala showed better growth and pursued cube law (b=3.94) followed by Cyprinus carpio (b=3.11) while Labeo rohita (b=2.79) and Catla catla (b=2.70) exhibited closed to ideal and Hypophthalmichthys molitrix showed poor b values (b=1.85). L/W values and coefficient of condition showed ideal growth of five carp species from Keenjhar Lake, District Thatta, Sindh, Pakistan.

These case studies endeavor to report incidences of caudal fin deformities in several commercial fishes living in natural populations in the Saudi Arabian coastal waters of the Arabian Gulf. Two groups of anomalies were observed, slight and severe. The carangid species, Parastromateus niger (Bloch) and the soleid species, Euryglossa orientalis (Bloch & Schneider), had slight cases of caudal fin abnormalities, while the species Oreochrromis mossambicus (Peters), Epinephelus stoliczkae (Day), Diagramma pictum (Thunberg), Cephalopholis hemistiktos (Rüppell), Lethrinus nebulosus (Forsskål), and Lutjanus sanguineus (Cuvier) had severe deformities. The abnormalities were assessed by morphological diagnosis. None of the cases was fatal as they occurred in adult individuals. The possible causes for these deformities as well as the suitability of this kind of case study for environmental monitoring are discussed. Further studies should be conducted from the perspective of pollution.

Wyeomyia (Wyeomyia) mitchellii (Theobald) (Diptera: Culicidae) was recovered for the first time on Guam, United States of America, in 2017. Larval specimens were collected from water-filled axils of bromeliads during a larval survey carried out in a residential neighborhood of the Chalan Pago/Ordot area. Native to the New World, Wy. mitchellii has likely made its way to the Pacific Islands through the possibly illegal import of ornamental bromeliads. While this mosquito does not represent a significant threat to public health, this finding highlights the vulnerability of the Pacific Islands to the introduction of exotic species, including mosquito species that may increase public health risks.

Postoperative atrial fibrillation (POAF) is a common complication after coronary artery bypass grafting (CABG) and is associated with increased short-term and long-term mortality. While the precise etiology of POAF remains unclear, inflammation is a known contributing factor. Preliminary studies have suggested that an elevated preoperative platelet-to-lymphocyte ratio (PLR), an inexpensive and readily available novel inflammatory biomarker, may be associated with increased incidence of POAF after CABG. This study sought to further investigate this hypothesis.The study cohort included all patients undergoing isolated CABG, with no prior history of arrhythmia, who were operated on between August 1, 2010, and December 31, 2018, at a major Australian tertiary center (n = 1457). Patients were divided into low (86) or high (≥86) PLR groups based on an optimal cutoff derived from receiver-operating characteristic curve analysis. The incidence of POAF was then compared. Categorical variables were analyzed using the chi-square test and continuous variables using logistic regression.Of 1457 patients, 495 (34.0%) developed POAF. There was no statistically significant difference in the incidence of POAF between patients in the high-PLR and low-PLR groups (34.8% vs 31.0%; P = .22). Using multivariable logistic regression analysis, high PLR was not independently associated with POAF (odds ratio, 1.04; P = .78).Elevated preoperative PLR is not independently associated with POAF in patients undergoing isolated CABG. The findings of this study differ from those of 2 previous smaller studies.

Background Although acute coronary syndromes (ACS) are a major cause of morbidity and mortality, relationships with biologically active lipid species potentially associated with plaque disruption/erosion in the context of their lipoprotein carriers are indeterminate. The aim was to characterize lipid species within lipoprotein particles which differentiate ACS from stable coronary artery disease. Methods and Results Venous blood was obtained from 130 individuals with de novo presentation of an ACS (n=47) or stable coronary artery disease (n=83) before coronary catheterization. Lipidomic measurements (533 lipid species; liquid chromatography electrospray ionization/tandem mass spectrometry) were performed on whole plasma as well as 2 lipoprotein subfractions: apolipoprotein A1 (apolipoprotein A, high‐density lipoprotein) and apolipoprotein B. Compared with stable coronary artery disease, ACS plasma was lower in phospholipids including lyso species and plasmalogens, with the majority of lipid species differing in abundance located within high‐density lipoprotein (high‐density lipoprotein, 113 lipids; plasma, 73 lipids). Models including plasma lipid species alone improved discrimination between the stable and ACS groups by 0.16 (C‐statistic) compared with conventional risk factors. Models utilizing lipid species either in plasma or within lipoprotein fractions had a similar ability to discriminate groups, though the C‐statistic was highest for plasma lipid species (0.80; 95% CI, 0.75–0.86). Conclusions Multiple lysophospholipids, but not cholesterol, featured among the lipids which were present at low concentration within high‐density lipoprotein of those presenting with ACS. Lipidomics, when applied to either whole plasma or lipoprotein fractions, was superior to conventional risk factors in discriminating ACS from stable coronary artery disease. These associative mechanistic insights elucidate potential new preventive, prognostic, and therapeutic avenues for ACS which require investigation in prospective analyses.

A subset of a larger and heterogeneous class of disorders, the congenital myasthenic syndromes (CMS) are caused by pathogenic variants in genes encoding proteins that support the integrity and function of the neuromuscular junction (NMJ). A central component of the NMJ is the sodium-dependent high-affinity choline transporter 1 (CHT1), a solute carrier protein (gene symbol SLC5A7), responsible for the reuptake of choline into nerve termini has recently been implicated as one of several autosomal recessive causes of CMS. We report the identification and functional characterization of a novel pathogenic variant in SLC5A7, c.788C>T (p.Ser263Phe) in an El Salvadorian family with a lethal form of a congenital myasthenic syndrome characterized by fetal akinesia. This study expands the clinical phenotype and insight into a form of fetal akinesia related to CHT1 defects and proposes a genotype-phenotype correlation for the lethal form of SLC5A7-related disorder with potential implications for genetic counseling.

4 Abstract: Biochemical analysis of non-conventional plant sources, Bermuda Grass, Nursery Grass (sages), Typha and Maize Spike (without grains) was done to determine the nutritional value to replace conventional sources such as rice bran, wheat bran and rice polish to prepare low cost fish feed. Analysis was carried out in the research lab of Institute of Biochemistry, University of Sindh, Jamshoro. It was observed that Bermuda grass and Nursery grass (sagas) have good protein value as 2.84 and 10.97, respectively. It is also observed that these non-conventional plants are a good source of energy and easily available around the year.

The catch and effort data analysis (CEDA) and ASPIC (a stock assessment production model incorporating covariates) computer software packages were used to estimate the maximum sustainable yield (MSY) from the catch and effort data of Greater lizardfish Saurida tumbil fishery of Pakistan from 1986 to 2009. In CEDA three surplus production models of Fox, Schaefer and Pella-Tomlinson were used. Here initial proportion (IP) of 0.5 was used because the starting catch was roughly 50% of the maximum catch. With IP = 0.5, the estimated MSY from Fox model were 20.59 mt and 38.16 mt for normal and log-normal error assumptions, while the MSY from Schaefer and Pella-Tomlinson were 60.40, 60.40 and 60.40 mt, for normal, log-normal and gamma error assumptions respectively. The MSY values from Schaefer and Pella-Tomlinson models of three error assumptions were the same. The R2 values from those three models were above 0.6. When IP = 0.5, the MSY values estimated from ASPIC from Fox were 132 mt, and from logistic model were 69.4 mt, with R2 value above 0.8. Therefore we suggest the MSY of S. tumbil fishery from Pakistan to be 60–70 mt, which is higher than the latest catch, thus we would recommend that the fishing efforts for this fishery may be kept at the current level.

Thirteen body proportions of the clupeid species, Tenualosailisha were investigated from Manjhand locality on the Indus River, Pakistan. Negative allometricgrowths for all morphometric traits examined were attained. The highest value of ‘b’ coefficient obtained was at its highest level for fork length (0.8834) and its lowest value for eye diameter (0.0398). The correlation coefficient value (R2) was at its lowest value for the relationship of the pectoral fin length-total fish length (0.46), the medium value of 0.77 and 0.80 were obtained for dorsal fin base length and anal fin base length respectively, while the highest value of 0.99 was attained for the relationship of both fork and standard lengths-total length and 0.98 for caudal peduncle length followed by 0.94 for the relationship of postorbital length-total fish length. The present report provides data to fishery biologists on body proportions of T. ilisha from the Indus River valley, Pakistan to support in development of management policies for this fish species.

The olfactory organs of loach Triplophysa dalaica were examined under a scanning electron microscope, sampled from the Dali-Nor Lake, Inner Mongolia, China. The olfactory organs are oval in shape, lying in the olfactory chamber on the dorsal side of the head. Ten pairs of lamellae in the rosette are present on each side of the middle raphe. Lamellae are covered with cilia at some margins. The surface of the olfactory lamellae is divided into three epithelial regions: sensory, ciliate non-sensory and non-ciliated non-sensory epithelium. Sensory epithelium consists of receptors and supporting cells, ciliated non-sensory epithelium is covered with dense cilia and non-receptor epithelium is covered with ciliated stratified epithelial cells and mucus cells. Cells other than epithelial cells present on the surface of the rosette are related to the significant olfactory function in the fish concerned.

Sharks belonging to the family Hexanchidae have six or seven gill slits, unlike all other elasmobranchs, which have five gill slits. Their olfactory organs have a round shape, which is common for holocephalans, but not for elasmobranchs. Thus, the shape of the olfactory organ represents a further, less striking, peculiarity of this family among elasmobranchs. Despite that, the microscopic anatomy and histology of the olfactory organ have not yet been studied in any species of this family. Here, an anatomical and histological description of the olfactory organ of the sharpnose sevengill shark Heptranchias perlo is given. The organ is a rosette, with a central raphe and 31-34 primary lamellae, which bear secondary lamellae with a more or less branched shape. The elastic connective capsule which envelops the olfactory rosette possibly changes its shape along with water influx. In the olfactory epithelium, the supporting cells also have a secretory function, while no specialized mucous cells are visible; regarding this feature the olfactory epithelium of H. perlo differs from that of other chondrichthyan species. The immunohistochemical investigation of the sensory epithelium shows the absence of immunoreactivity for Galphaolf in receptor neurons, which confirms previous observations in Chondrichthyes.

Maximum sustainable yield estimates of spiny lobster fishery were analyzed using catch effort data analysis (CEDA) computer programme. The major parameters of this package are: Maximum sustainable yield (MSY), catchability coefficient (q) carrying capacity (K), intrinsic growth rate (r), Replacement yield and Final population. CEDA has ability to assess the parameters of Fox, Schaefer and PellaTomlinson mod� els. In addition it has an ability to estimate three error assumptions i.e. normal, log normal and gamma. In this study, the Maximum sustainable yield outputs of three models of Fox, Schaefer and PellaTomlinson are: 828 t, 970 t and 970 t respectively. The outputs of error assumption of normal and log normal are 983 t (R 2 = 0.57) and 950 t (R 2 = 0.53) in Schaefer and PellaTomlinson models respectively. MSY outputs of normal error assumption of Fox are 817 t (R 2 = 0.56). All the gamma error assumptions are (790 t) similar. The coef� ficient of variation (cv) of the estimated MSY was about 0.7 and the larger value (1.0) whereas lowest (0.5) were recorded. The Fox model output are more conservative hence the best fits and is close to the annual aver� age landings of the spiny lobster fishery in Pakistan.

Blooms of jellyfishes were studied at 3 sites, namely Bhanbore, Mirpur Sakro, and Keti Bunder. The sampling was carried out from April 2005 to March 2006. Only 2 species of jellyfish, Catostylus perezi and Rhizostoma pulmo, were found in samples. C. perezi was present at all 3 sampling sites, whereas R. pulmo was found only at Keti Bunder. Specimens of C. perezi appeared in the subsurface waters for a period of 6-8 months during April to August 2006 and February to March 2006. The smallest specimens of C. perezi appeared in January, and a gradual increase in size was observed in the population until August. The smallest specimens of R. pulmo were found in February, and their largest specimens occurred in July. The numeric abundance of medusae in zooplankton was also studied. They were more abundant at Mirpur Sakro, with a peak in December and January, while at Keti Bunder their highest number was noted in May. Their number at Bhanbore was comparatively lower than at the other 2 sites. No significant difference in physical oceanographic factors such as salinity, pH, dissolved oxygen, and suspended load of the sampling site was found, except for water temperature.

The surface of the olfactory epithelium of two species of cave loaches in China, Oreonectes polystigmus and O. guananensis, was studied by scanning electron microscopy (SEM). The structure of the olfactory organ of the two species is quite different from each other; as well, the distribution patterns of cell types in the olfactory epithelium of the studied species showed interesting features. A needle-like spine is visible on the lamellae of the olfactory organ of O. polystigmus, which is a unique character in this species. Ciliated non-sensory cells and microvillus sensory cells showed a different distribution in the two species, being more numerous in O. polystigmus. The non-sensory elements in O. guananensis were ciliated non-sensory cells, with microridges and chloride cells. The presence of chloride cells in the olfactory epithelium of O. guananensis may be of special interest in this species; otherwise, possible differences and physiological changes of the concerned species should be taken i...

Bio Medical Waste management has received highest priority in hospitals, after introduction of the act “Bio Medical waste management and Handling rules 1998” by The Ministry of Environment and Forest. 0.33 million tones of Bio medical waste is being generated annually in India2. Hospital acquired infections are increasing due to improper waste management practice. A cross sectional study on knowledge and practice of Bio Medical waste management was conducted at a tertiary care teaching hospital from 1st June to 31st august 2016. Interestingly the practice of Bio Medical waste management was good in spite of the knowledge levels not being up to the mark in lower cadre staff. Majority of the doctors, nurses and other paramedical staff have adequate knowledge on bio medical waste management. Except a few lower cadre staff, remaining health care personnel are well versed with universal work precautions. The practice of segregation, storage and transportation of biomedical waste was according to the prescribed guidelines.

Complete mitochondrial genome of catfish, Eutropiichthys vacha, was isolated by LA PCR (TakaRa LAtaq, Dalian, China); and sequenced by Sanger’s method to obtain the complete mitochondrial genome, which is listed Critically Endangered and Red-listed species. The complete mitogenome was 16,478 bp in length and contains 13 typical vertebrate protein-coding genes, 2 rRNA and 22 tRNA genes. The whole genome base composition was estimated to be 31.06% A, 27.59% C, 15.65% G, and 25.68% T. The complete mitochondrial genome of catfish, E. vacha provides the fundamental tool for genetic breeding and conservation studies.

Large multigene families of zinc finger proteins are expressed in vertebrates. One way of approaching their function is to characterize their structure, expression and biochemical properties. XFG 5-1 is a Xenopus zinc finger protein which is widely transcribed in oocytes, embryos and adult tissues. It carries a novel, non-finger repeat structure, which is common to a subfamily of Xenopus zinc finger proteins. The bacterially expressed protein exhibits specific RNA homopolymer binding activities with the zinc finger domain being sufficient for this ability. These findings suggest that XFG 5-1 serves a general biological function involving its RNA binding capacity.

A large family of C2H2 (Kruppel-like) zinc finger protein genes is maternally transcribed in Xenopus oocytes; many of the corresponding mRNAs are actively translated post-fertilization, before the onset of zygotic activation of transcription. With the aim of asking if any of these stored mRNAs have a function in Xenopus development, we made use of antisense oligonucleotide mediated, targeted RNA destruction. Injected oocytes lose the entire pool of C2H2 zinc finger protein encoding mRNAs. They are indistinguishable from control oocytes in their abilities to mature in vitro and to be fertilized in vitro. Embryos generated from such oocytes develop normally until tadpole stage. These findings do not rule out the possibility that C2H2 zinc finger protein genes are involved in developmental control in Xenopus. However, they do suggest that the biological function for at least some of the early expressed zinc finger proteins in Xenopus differs in important aspects from the way Kruppel or other DNA binding factors act as developmental regulators in Drosophila.

The developing Chick has been widely used as a model organism for research studies in developmental biology. Various aspects of ethanol (EtOH) toxicity during embryonic development have been documented in experimental studies. The studies on chick embryo address the effects of EtOH on craniofacial abnormalities and angiogenesis. The purpose of this study was to assess the effects of a single dose of ethanol on survival rate and angiogenesis of chick embryos during early stages of development. Chick eggs were incubated at 37oC in the humidified incubator, after 72 hours of incubation these eggs were removed from incubator, and treated with a single doses of 1%, 5%, 10%, 13% and 15% EtOH. The effects on survival rate and angiogenesis were recorded on ethanol treated chick embryos. The survival rate was slightly reduced with 1% and 5% EtOH, however with increasing dose of 10% the survival rate was reduced to 64% and at 15% EtOH complete death was observed. Our results also indicate that treatment of EtOH with 1% and 5% did not have any obvious effects on vessels formation in comparison with the BSS treated embryos. However, treatment of chick embryo with 10%, 13% and 15% EtOH severely inhibited the blood vessels formation.

Length-weight relationships were estimated for the first time for five loaches of the Jinshajiang River, China. Four of the species are endemic to China. The scientific names are: Clea dabryi (Sauvage, 1874); Homatula variegata (Dabry de Thiersant, 1874); Sinibotia superciliaris (Gunther, 1892); Triplpphysa anterodorsalis (Zhu & Cao, 1989); and Triplophysa leptosoma (Herzenstein, 1888).

Two cDNAs encoding Myb-related proteins have been cloned from Xenopus laevis and they have been termed Xmyb1 and Xmyb2. The Xmyb1 cDNA clone codes for an open reading frame of 733 amino acids and exhibits a high degree of similarity over the entire predicted protein sequence with the human B-Myb protein. Xmyb2 is a partial cDNA clone encoding three copies of amino-terminal tandem repeat elements typical for the Myb DNA-binding domain. The predicted protein sequence is most closely related to the human A-Myb gene product. In vitro translation of two deletion mutants of Xmyb1, truncated in the 3'-portion of the open reading frame, results in protein products which cross-react with polyvalent as well as monoclonal antibodies directed against the human c-Myb protein. The same two XMyb1 proteins, which both contain the complete set of aminoterminal repeats, specifically bind to the c-Myb-specific DNA binding sequence as evidenced by electrophoretic mobility shift analysis in vitro. RNA expression profiles of Xmyb1 and -2 are very different from each other; Xmyb1 is present throughout oogenesis and early Xenopus embryogenesis; in adult tissue it is primarily detected in blood. In contrast, Xmyb2 is expressed at only very low levels during oogenesis, not detectable in embryonic RNA preparations, and in adult tissue it is predominantly expressed in testis, with only a very low level seen in blood.

The molecular description of diverse nucleic acid binding proteins has led to the definition of structurally related families of such polypeptides. They often carry multiple modular functional domains, and one conserved motif responsible for nucleic acid binding is the zinc finger repeat. It has originally been discovered in TFIIIA, a 5S gene specific transcription factor from Xenopus. This protein contains nine tandem repeats of a sequence element referred to as the C2H 2 zinc finger since it contains highly conserved pairs of cysteine and histidine residues (Miller et al., 1985; Brown et al., 1985), which fold each of these sequences about a zinc atom (Diakun et al., 1986). Following its discovery in TFIIIA, variants of the zinc finger motif have been detected in many other, often regulatory proteins. It should be pointed out that the term 'zinc finger' has been applied to several other structures such as the cysteine rich DNA binding domain of ligand dependent nuclear receptors (Evans, 1988; Green and Chambon, 1988; Beato, 1989) or a group of retroviral RNA binding proteins (Katz and Jentoft, 1989)'. Here, we will focus our discussion on the C2H 2 class of zinc finger proteins (ZFPs), of which TFIIIA is a prototype.

The interaction of ribosomal protein EL23 from E. coli and L25 from yeast with yeast 26S rRNA was analysed by nitrocellulose filter binding and RNase protection experiments using both intact rRNA and various fragments prepared by in vitro transcription of cloned yeast rDNA regions in the SP6 system. The results show that EL23 efficiently and specifically interacts with the region of 26S rRNA previously identified as the binding site for the yeast ribosomal protein L25. A comparison of the oligonucleotides resulting from limited RNase T1 digestion of the heterologous EL23/26S rRNA complex with those obtained by the same treatment of the homologous L25/26S rRNA complex showed that the molecular details of the two r-protein/rRNA interactions are highly similar if not identical. Using the synthetic 26S rRNA fragments we could demonstrate that all information for the formation of a biologically active binding site is located within the region of the rRNA delimited by the sequences protected by L25 against RNase T1 digestion. Part of the sequence at the 3' end of the 5'-distal protected region, however, was found not to be essential for r-protein binding although it does enhance the efficiency of this binding. Binding experiments using synthetic mouse 28S rRNA fragments showed that neither EL23 nor L25 interact with the structural equivalent of their respective cognate binding sites present in this mammalian rRNA. We argue that the structure of the expansion sequence present in this region of mouse 28S rRNA is a major cause of this failure.

The heterologous interaction of Escherichia coli ribosomal protein EL11 with yeast 26 S and mouse 28 S rRNA was studied by analysing the ability of this protein to form a specific complex with various synthetic rRNA fragments that span the structural equivalent of the EL11 binding site present in these eukaryotic rRNAs. The fragments were obtained by SP6 polymerase-directed in-vitro run-off transcription of parts of the yeast or mouse large rRNA gene cloned behind the SP6 promoter. EL11 was found to protect an oligonucleotide fragment of 63 nucleotides from both the yeast and mouse transcripts against digestion by RNase T1. In both cases, the position of this fragment in the L-rRNA § sequence coincides almost exactly with that of the fragment previously found to be protected by EL11 in E. coli 23 S rRNA. Moreover, the protected yeast fragment was shown to be able to re-bind to EL11 by a nitrocellulose filter binding assay. A ribosomal protein preparation from Saccharomyces cerevisiae containing L15 (YL23) as well as the acidic proteins L44′, L44 and L45 protects exactly the same oligonucleotide fragment as does EL11 in both the yeast and mouse transcripts. Evidence is provided that L15, which is known to be structurally and functionally equivalent to EL11, is the rRNA-binding protein in this preparation. Thus the structural equivalent of the EL11 binding site present in yeast 26 S rRNA constitutes the second example of functional conservation of a ribosomal protein-binding site on rRNA between prokaryotes and eukaryotes.

The binding site of the yeast 60S ribosomal subunit protein L25 on 26S rRNA was determined by RNase protection experiments. The fragments protected by L25 originate from a distinct substructure within domain IV of the rRNA, encompassing nucleotides 1465-1632 and 1811-1861. The protected fragments are able to rebind to L25 showing that they constitute the complete protein binding site. This binding site is remarkably conserved in all 23/26/28S rRNAs sequenced to date including Escherichia coli 23S rRNA. In fact heterologous complexes between L25 and E. coli 23S rRNA could be formed and RNase protection studies on these complexes demonstrated that L25 indeed recognizes the conserved structure. Strikingly the L25 binding site on 23S rRNA is virtually identical to the previously identified binding site of E. coli ribosomal protein EL23. Therefore EL23 is likely to be the prokaryotic counterpart of L25 in spite of the limited homology displayed by the amino acid sequences of the two proteins.

Saccharomyces carlsbergensis 60 S ribosomal subunits were treated with the hetero-bifunctional crosslinking agent 2-iminothiolane and then subjected to mild UV irradiation to introduce protein-rRNA crosslinks. The major crosslinked products were identified as proteins L2, L3, L5, L19 and L23 of which L5 was found to be crosslinked at a 3–5-fold higher efficiency than the other four. Several additional proteins were crosslinked to a detectable but much lower extent.

Peritoneal mesothelium of the anterior abdominal wall of the rabbit was studied by the electron microscope. Mesothelial cells are flattened with somewhat oval nuclei and rest on a thin homogeneous discontinuous basement membrane separated from the outer cell membrane by a constant space. Attached to the basement membrane is a thick heterogeneous lamina with which collagen fibrils are associated. The cytoplasm shows occasional mitochondria, very few Golgi membranes, scanty granular endoplasmic reticulum and occasional dense microbodies. The cytoplasm is heavily packed with pinocytotic vesicles which open to the inside, to the outside and in the intercellular spaces as well. On the free surface long and unevenly distributed microvilli are present which show pinocytotic vesicles inside them. The presence of side branches taking origin from the main intercellular channel and opening to the outside or to the inside is suggested. Labyrinthine and fusiform intercellular spaces are seen. Occurrence of tight junctions of cell membranes underneath desmosomes in some intercellular boundaries is proposed. It is concluded that pinocytosis dominates the metabolic activities of the cell, which seems to have very little synthetic ability.

The fine morphology of, and the light microscopic distribution of ATPase in, pancreatic secretory capillaries suggest that they may be absorptive channels receiving material from the general blood circulation rather than secretory channels communicating with the duct system. This assumption is based upon many observations; 1. The pattern of microvilli of their wall differs from that of acinar lumen. 2. The material retained by them in ultrathin sections differs from that retained by acinar lumen. 3. They ramify, basally, to the level of Golgi region. 4. The lack of release of zymogen droplets in them. 5. Their points of origin from acinar lumen are controlled by zonulae occludentes. 6. Gulf-like extensions from the basal surface of acinar cell communicate with them. 7. Fenestrated blood capillaries run in their vicinity. 8. Blood capillaries and acinar cells share a joint basement lamina. 9. Light microscopically, ATPase activity is associated with their wall and not with the basal acinar cell surface.

Intercellular secretory capillaries in parotid glands, eccrine sweat glands and intracellular secretory capillaries in parietal cells of gastric glands were demonstrated histo-chemically by the use of the Wachstein-Meisel adenosinetriphosphatase (ATPase) technique in the rabbit, rat and guinea pig. However, with the Wachstein-Meisel 5-nucleotidase technique, secretory capillaries were not stained. For parotid glands, optimal incubation in ATPase substrate mixture was: in rabbit, 15 min; in rat, 2.5 hr; and in guinea pig, 2 hr. For eccrine sweat glands, optimal incubation was 15 min in rabbit, 30 min in rat and 15 min in guinea pig. For parietal cells of gastric glands, optimal incubation was 3 hr for all three species. Secretory capillaries were best demonstrated in the parotid by using rabbit tissue; in eccrine sweat glands, with rat tissue, and in parietal cells, guinea pig tissue. Since ATPase activity in cell membranes of secretory cells may play a part in the mechanism of transport of secretory produ...

When the gene dosage for the primary rRNA-binding ribosomal protein L25 in yeast cells was raised about 50-fold, the level of mature L25 transcripts was found to increase almost proportionally. The plasmid-derived L25 transcripts were structurally indistinguishable from their genomic counterparts, freely entered polysomes in vivo and were fully translatable in a heterologous in vitro system. Nevertheless, pulse-labelling for periods varying from 3–20 min did not reveal a significant elevation of the intracellular level of L25 protein. When pulse-times were decreased to 10–45 s, however, we did detect a substantial over production of L25. We conclude that, despite the strong RNA-binding capacity of the protein, accumulation of L25 is not controlled by an autogenous (pre-)mRNA-targeted mechanism similar to that operating in bacteria, but rather by extremely rapid degradation of excess protein produced.

The primary structure of 342 finger repeats encoded in 42 different cDNA clones isolated from Xenopus laevis oocyte and gastrula cDNA libraries has been determined. Comparative sequence analysis of the predicted protein sequences results in a consensus repeat sequence that has an extended conserved segment of 16 amino acid residues, including the evolutionary conserved H C link element, connected to a highly variable segment that is located in the finger loop region. Groups of tandem finger repeats are found to be organized in distinct higher-order structural units, with a pair of mutually distinct fingers being the most frequently observed second-order repeat unit. Structural features observed are discussed in respect to existing models for Zn finger structure and function.

The presence in the rat omentum of intercellular pores (the classical stomata of von Recklinghausen) between the mesothelial cells overlying aggregates of lymphoreticular cells (the classical milky spots of Ranvier) and the apparent migration of lymphocytes through these stomata were recorded for the first time by scanning electron microscopy. Previous studies on passage of cells across the peritoneum and omentum used experimentally administered cells, while in the present study no cells were administered to the rats and their own lymphocytes were observed in situ. The possible role of lymphocytes in the peritoneal cavity is also briefly discussed.

Spermatid residual bodies are released from Sertoli cells into the lumen of the seminiferous tubule apparently after, but not during or before, spermiation as generally thought: their subsequent fate, however, is not clear.

Treatment of yeast 60S ribosomal subunits with 0.5 M LiCl was found to remove all but six of the ribosomal proteins. The proteins remaining associated with the (26S + 5.8S) rRNA complex were identified as L4, L8, L10, L12, L16 and L25. These core proteins were split off sequentially in the order (L16 + L12), L10, (L4 + L8), L25 by further increasing the LiCl concentration. At 1.0 M LiCl only ribosomal protein L25 remains bound to the rRNA. Upon lowering the LiCl concentration the core proteins reassociate with the rRNA in the reverse order of their removal. The susceptibility of the ribosomal proteins to removal by LiCl corresponds quite well with their order of assembly into the 60S subunit in vivo as determined earlier [Kruiswijk et al. (1978) Biochim. Biophys. Acta 517, 378–389]. Binding studies in vitro using partially purified L25 showed that this protein binds specifically to 26S rRNA. Therefore our experiments for the first time directly identify a eukaryotic ribosomal protein capable of binding to high-molecular-mass rRNA. Binding studies in vitro using a blot technique demonstrated that core proteins L8 and LI6 as well as protein L21, though not present in any of the core particles, are also capable of binding to 26S rRNA to approximately the same extent as L25. About nine additional 60S proteins appeared to interact with the 26S rRNA, though to a lesser extent.

Freeze-etch preparations of mesothelial cells taken from the peritoneum of mouse reveal the presence of vesicles invaginating the apical and the basal cell surfaces. These vesicles are scarcely seen within the cytoplasm. Long tortuous tubular profiles extend for considerable distance within the cytoplasm and are frequently associated with the vesicles. The possible nature and role of the vesicles and the tubules in transport phenomena across the mesothelial barrier, are discussed in relation to the pore theory advanced by physiologists and the “stomata” concept observed by early German and contemporary anatomists. “Occludens” junctions of the leaky type are seen though their macular or zonular nature is yet to be established.

As seen in the scanning electron microscope, peritoneal mesothelial cells of the mouse diaphragm, anterior abdominal wall and intestinal serosa carry numerous microvilli. These microvilli are absent over certain areas of the cell surface and are. sometimes, interlocked in meshwork patterns or coronal formations. The apical cell membranes of the mesothelium at the base of the microvilli, are invaginated by many plasmalemmal vesicles and vacuoles and carry a number of protruding spherical structures. Deep circular craters, giving the impression of stomata, are also visible.

As seen by scanning electron microscopy, the mitochondrial helix in the developing midpiece of mouse testicular spermatozoa is dextral in direction and consists of spherical mitochondrial units arranged in an orderly array of four units per gyre: three appearing in face view and a fourth hidden from view at the back of the gyre. As the spermatozoa mature, the dextral helix is transformed into a sinistral helix. Its constituent spherical mitochondria either change direction abruptly without changing shape; or having first become semilunar or diamond-shaped, they change direction gradually. Mitochondrial division follows the change in helical pitch producing a double sinistral helix. The spherical (or semilunar/diamond-shaped) mitochondria presumably elongate to form the units of the mature midpiece.