Genome-wide CRISPR Screens Reveal Host Factors Critical for SARS-CoV-2 Infection

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DDT induced ethological changes in estuarine fish

Synopsis Experiments were carried out to study the feeding rates of the predator fish Therapon jarbua (Forsk) on mullet juveniles, before and after treatment with DDT. Mullet juveniles treated with a subacute concentration, were refused by the control predators, whereas predators treated with a subacute concentration consumed more mullet juveniles. In the present study crescent perch T. jarbua were exposed to subacute and acute concentrations of DDT, and their behaviour was compared with that of the control predators. There were changes in oriented behaviour and co-ordinated movements, and in feeding, aggression and comfort behaviour of the fish. Inflammation in the gills, and caudal fin serration, were noticed in treated fishes. The findings presented here throw light on fundamental pathways by which pollutants interact with the behaviour of fishes.     

Low-Level Microwave Irradiations Affect Central Cholinergic Activity in the Rat

Sodium-dependent high-affinity choline uptake was measured in various regions of the brains of rats irradiated for 45 min with either pulsed or continuous-wave low-level microwaves (2,450 MHz; power density, 1 mW/cm2; average whole-body specific absorption rate, 0.6 W/kg). Pulsed microwave irradiation (2-microseconds pulses, 500 pulses/s) decreased choline uptake in the hippocampus and frontal cortex but had no significant effect on the hypothalamus, striatum, and inferior colliculus. Pretreatment with a narcotic antagonist (naloxone or naltrexone; 1 mg/kg i.p.) blocked the effect of pulsed microwaves on hippocampal choline uptake but did not significantly alter the effect on the frontal cortex. Irradiation with continuous-wave microwaves did not significantly affect choline uptake in the hippocampus, striatum, and hypothalamus but decreased the uptake in the frontal cortex. The effect on the frontal cortex was not altered by pretreatment with narcotic antagonist. These data suggest that exposure to low-level pulsed or continuous-wave microwaves leads to changes in cholinergic functions in the brain.     

Acute phase response to recombinant interleukin-6 and macrophage- and fibroblast-derived crude cytokine preparations in primary cultures of mouse hepatocytes

A number of acute phase proteins were determined by electroimmunoassay in media from CBA mouse hepatocytes cultured for 2 days with human recombinant IFN beta 2/IL-6, as well as with conditioned media from LPS-stimulated rat macrophages, and of murine L fibroblasts. It was found that human recombinant IL-6 caused three-fold increase in secretion of fibrinogen, while haptoglobin, complement C3 and transferrin were increased respectively, to 168 per cent, 151 per cent, and 145 per cent of the control. DEX(10(-7) M) in DMEM supplemented with 5 per cent FCS, enhanced the IL-6 effect on the three positive acute phase proteins. IL-6 elevated haptoglobin mRNA in mouse hepatocytes to a degree comparable with the concentration of the protein in the culture medium. The effect of conditioned media from murine fibroblasts and peritoneal rat macrophages was generally similar to that of recombinant IL-6. However, both natural preparations of the cytokines caused decrease in albumin and alpha-1-proteinase inhibitor secretion.     

The morphology of allograft rejection in Styela plicata (Urochordata: Ascidiacea)

Summary This study identifies three discrete processes responsible for the rejection of tunic tissue transplanted between individuals of the solitary ascidian Styela plicata. The first stage of rejection is characterized by the destruction of blood vascular components within incompatible allografts. In the second phase, dense boundaries of extracellular material are deposited between grafts and the surrounding host tunic, effectively amputating the transplanted tissues. Finally, detached transplants undergo a gradual necrosis which results in the total degeneration of extracellular graft matrices. Of these three phases, the initial cellular depletion of allografts is responsible for the immunological specificity that is characteristic of histocompatibility in S. plicata. The subsequent amputation and necrosis of extracellular graft matrices are taken to be non-specific consequences of the initial cellular reactivity.     

The acute effect of 30 min of moderate exercise on high density lipoprotein cholesterol in untrained middle-aged men

Fifteen middle-aged, untrained (defined as no regular exercise) men (mean age 49.9 years, range 42-67) cycled on a cycle ergometer at 50 rpm for 30 min at an intensity producing 60% predicted maximum heart rate [(fc,max), where fc,max = 220 - age]. Total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and triglyceride (Tg) concentrations were measured from fasting fingertip capillary blood samples collected at rest, after 15 and 30 min of exercise, and at 15 min post-exercise. The mean HDL-C level increased significantly from the resting level of 0.85 mmol.l-1 to 0.97 mmol.l-1 (P < 0.05) after 15 min of exercise, increased further to 1.08 mmol.l-1 (P < 0.01) after 30 min of exercise and remained elevated at 1.07 mmol.l-1 (P < 0.01) at 15 min post-exercise. These increases represented changes above the mean resting level of 14.1%, 27.1% and 25.9% respectively. The HDL-C/LDL-C ratio increased significantly from a resting ratio of 0.20 to 0.26 after 30 min of exercise (P < 0.01) and to 0.24 at 15 min post-exercise (P < 0.05). The mean Tg level increased significantly from a resting level of 0.88 mmol.l-1 to 1.05 mmol.l-1 after 15 min, and to 1.06 mmol.l-1 after 30 min of exercise (P < 0.05 at each time). The TC/HDL-C ratio decreased significantly (P = 0.05) after 30 min of exercise and at 15 min post-exercise by 18.8% and 14%, respectively. No significant changes were observed in the levels of TC or LDL-C over time.(ABSTRACT TRUNCATED AT 250 WORDS)     

血清胃泌素变化与急性胃粘膜病变关系的研究

对大白鼠血清中胃泌素水平的变化与急性胃粘膜病变的关系进行了初步的研究,结果表明以消炎痛为诱因引起的急性胃粘膜病变大白鼠血清胃泌素水平明显增高。而维酶素可以抑制因消炎痛引起的急性胃粘膜病变时血清胃泌素的释放,对胃粘膜具有保护作用。     

六种选矿药剂对藻类的毒性比较

本文评价了六种选矿药剂对藻类的毒性效应,它们对斜生栅藻的毒性大小排列顺序是:二号油>Fu>0145>Yx>MPA>S-808,96h-EC_(50)值分别为41.2,50.1,82.0,177.8,198.2和900ppm。六种选矿药剂对藻类毒性最大的是二号油,毒性最小的是S-808。对藻类细胞形态的观察结果表明,0145对藻类的细胞形态有轻度的致畸效应,在其它五种药剂的培养物中,均未发现畸变细胞。在室温下存放10d后MPA,0145和二号油,毒性明显下降,其下降速率的顺序是:MPA>0145>二号油。藻类对S-808具有净化脱色作用,100ppm浓度的S-808溶液经藻类作用32d后,其色度可减少48％,作用62d和93d,色度分别降低54％和58％。0145抑制藻类的光合放氧,经50,100和200ppm浓度的0145处理4h后,与对照相比,藻类的光合放氧速率分别下降15、34和36％。     

Recruitment of helper T cells for induction of tumour rejection by cytolytic T lymphocytes

Immunotherapy of cancer could be possible in cases in which competent effector T cells can be induced. Such an approach depends on expression of tumour-specific antigens by the tumour cells and on the availability of sufficient costimulatory support for activation of cytotoxic T lymphocytes. Here, a strategy for helper T cell recruitment for induction of tumour-specific cytotoxic immune responses is presented. Allogenic MHC class II molecules were introduced into tumour cells by cell fusion. These hybrid cells, when injected into mice, induced rejection of an established tumour. The contribution of CD4-expressing helper T cells in the induction phase and of CD8-expressing T cells in the effector phase of the immune response was demonstrated. The approach described could be applicable to cases in which a suitable tumour antigen is present but not identified; it employs regulatory interactions that govern physiological immune responses and is designed to be minimally invasive.