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441.
Lina Vanagaite Michael R. James Galit Rotman Kinneret Savitsky Anat Bar-Shira Shlomit Gilad Yael Ziv Vitalia Uchenik Adam Sartiel Francis S. Collins Val C. Sheffield Charles W. Richard III Jean Weissenbach Yosef Shiloh 《Human genetics》1995,95(4):451-454
The locus of the autosomal recessive disorder ataxia-telangiectasia (A-T) has been assigned by linkage analysis with biallelic markers to a 4-Mb interval on chromosome 11q22-23, between GRIA4 and D11S1897. We have undertaken to saturate the A-T region with highly polymorphic microsatellite markers. To this end, we have identified seven new polymorphic CA-repeats in this region, and have mapped to it five new markers generated by Genethon and the Cooperative Human Linkage Center. These markers are in addition to 12 others that we have previously mapped or generated at the A-T locus. All 24 markers have been integrated into a high-density microsatellite map spanning some 6 Mb DNA. This map, which contains the A-T locus and flanking sequences, allows the construction of extensive, highly informative haplotypes. 相似文献
442.
Yifat Elharar Ziv Roth Inna Hermelin Alexandra Moon Gabriella Peretz Yael Shenkerman Marina Vishkautzan Isam Khalaila Eyal Gur 《The EMBO journal》2014,33(16):1802-1814
Intracellular protein degradation is an essential process in all life domains. While in all eukaryotes regulated protein degradation involves ubiquitin tagging and the 26S‐proteasome, bacterial prokaryotic ubiquitin‐like protein (Pup) tagging and proteasomes are conserved only in species belonging to the phyla Actinobacteria and Nitrospira. In Mycobacterium tuberculosis, the Pup‐proteasome system (PPS) is important for virulence, yet its physiological role in non‐pathogenic species has remained an enigma. We now report, using Mycobacterium smegmatis as a model organism, that the PPS is essential for survival under starvation. Upon nitrogen limitation, PPS activity is induced, leading to accelerated tagging and degradation of many cytoplasmic proteins. We suggest a model in which the PPS functions to recycle amino acids under nitrogen starvation, thereby enabling the cell to maintain basal metabolic activities. We also find that the PPS auto‐regulates its own activity via pupylation and degradation of its components in a manner that promotes the oscillatory expression of PPS components. As such, the destructive activity of the PPS is carefully balanced to maintain cellular functions during starvation. 相似文献
443.
Diageotropic side branches in runner type peanuts assume anorthotropic position when grown in the dark but return to aplagiotropic postition when transferred back to light. The effectof light on the trailing habit of lateral branches depends onthe quality and intensity of the light taking place under blue+farred light, but not under blue alone. Light intensity below 28Kergs.cm2.sec1 changed the growth of the runner'slaterals from trailing to erect. Inhibitors of both GA and auxinactivity were higher in the laterals of runners than in thoseof the erects. Along with the change in the trailing habit bylow light intensity, a decrease in inhibitor level was observed.Gibberellin-like activity was smaller in both extracts and diffusatesof the growing tip of lateral branches than in the main axis.An inhibitor found only in lateral branches of runner type plantscould be detected in erect plants in the presence of auxin.The predominant factor controlling differences in the growthhabit of side branches of the erect and runner types is thepresence of an inhibitor; while, within each type, levels ofgibberellin seem to account for the different growth habit ofthe axis and laterals. (Received January 23, 1973; ) 相似文献
444.
Yukio Ikeda Ehud Ziv Eleazar Shafrir Luitgard Mosthaf-Seedorf 《Experimental diabetes research》2002,3(3):205-212
Protein tyrosine phosphatases (PTPases) have been suggested
to modulate the insulin receptor signal transduction pathways.We
studied PTPases in Psammomys obesus, an animal model of nutritionally
induced insulin resistance. No changes in the protein
expression level of src homology PTPase 2 (SHP-2) (muscle, liver)
or leukocyte antigen receptor (LAR) (liver) were detected. In contrast,
the expression level of PTPase 1B (PTP 1B) in the skeletal
muscle, but not in liver, was increased by 83% in the diabetic animals,
compared with a diabetes-resistant line. However, PTP 1B–
specific activity (activity/protein) significantly decreased (50% to
56%) in skeletal muscle of diabetic animals, compared with both
the diabetes-resistant line and diabetes-prone animals. In addition,
PTP 1B activity was inversely correlated to serum glucose level
(r = –.434, P < .02). These findings suggest that PTP 1B, though
overexpressed, is not involved in the susceptibility to insulin resistance
in Psammomys obesus and is secondarily attenuated by
hyperglycemia or other factors in the diabetic milieu. 相似文献
445.
Hagit Hak Hagai Raanan Shahar Schwarz Yifat Sherman Savithramma P. Dinesh-Kumar Ziv Spiegelman 《Molecular Plant Pathology》2023,24(8):838-848
The tomato Tm-22 gene was considered to be one of the most durable resistance genes in agriculture, protecting against viruses of the Tobamovirus genus, such as tomato mosaic virus (ToMV) and tobacco mosaic virus (TMV). However, an emerging tobamovirus, tomato brown rugose fruit virus (ToBRFV), has overcome Tm-22, damaging tomato production worldwide. Tm-22 encodes a nucleotide-binding leucine-rich repeat (NLR) class immune receptor that recognizes its effector, the tobamovirus movement protein (MP). Previously, we found that ToBRFV MP (MPToBRFV) enabled the virus to overcome Tm-22-mediated resistance. Yet, it was unknown how Tm-22 remained durable against other tobamoviruses, such as TMV and ToMV, for over 60 years. Here, we show that a conserved cysteine (C68) in the MP of TMV (MPTMV) plays a dual role in Tm-22 activation and viral movement. Substitution of MPToBRFV amino acid H67 with the corresponding amino acid in MPTMV (C68) activated Tm-22-mediated resistance. However, replacement of C68 in TMV and ToMV disabled the infectivity of both viruses. Phylogenetic and structural prediction analysis revealed that C68 is conserved among all Solanaceae-infecting tobamoviruses except ToBRFV and localizes to a predicted jelly-roll fold common to various MPs. Cell-to-cell and subcellular movement analysis showed that C68 is required for the movement of TMV by regulating the MP interaction with the endoplasmic reticulum and targeting it to plasmodesmata. The dual role of C68 in viral movement and Tm-22 immune activation could explain how TMV was unable to overcome this resistance for such a long period. 相似文献
446.
Joseph Meyerovitch Yigal Balta Ehud Ziv Joseph Sack Eleazar Shafrir 《Experimental diabetes research》2002,3(3):199-204
Phosphotyrosine phosphatase (PTPase) activity and its regulation
by overnight food deprivation were studied in Psammomys
obesus (sand rat), a gerbil model of insulin resistance and nutritionally
induced diabetes mellitus. PTPase activity was measured
using a phosphopeptide substrate containing a sequence identical
to that of the major site of insulin receptor (IR) β-subunit autophosphorylation.
The PTPase activity in membrane fractions was 3.5-,
8.3-, and 5.9-fold lower in liver, fat, and skeletal muscle, respectively,
compared with corresponding tissues of albino rat.Western
blotting of tissue membrane fractions in Psammomys showed lower
PTPase and IR than in albino rats. The density of PTPase transmembrane
protein band was 5.5-fold lower in liver and 12-fold
lower in adipose tissue. Leukocyte antigen receptor (LAR) and IR
were determined by specific immunoblotting and protein bands
densitometry and were also found to be 6.3-fold lower in the liver
and 22-fold lower in the adipose tissue in the hepatic membrane
fractions. Liver cytosolic PTPase activity after an overnight food
deprivation in the nondiabetic Psammomys rose 3.7-fold compared
with postprandial PTPase activity, but it did not change significantly
in diabetic fasted animals. Similar fasting-related changes
were detected in the activity of PTPase derived from membrane
fraction. In conclusion, the above data demonstrate that despite
the insulin resistance, Psammomys is characterized by low level of
PTPase activities in membrane and cytosolic fractions in all 3 major insulin responsive tissues, as well as in liver. PTPase activity does
not rise in activity as a result of insulin resistance and nutritionally
induced diabetes. 相似文献
447.
448.
Carmit Ziv Dilip Kumar Noa Sela Maxim Itkin Sergey Malitsky Arthur A. Schaffer Dov B. Prusky 《Environmental microbiology》2020,22(7):2870-2891
Colletotrichum gloeosporioides and Penicillium expansum cause postharvest diseases in tropical and deciduous fruit. During colonization, C. gloeosporioides and P. expansum secrete ammonia in hosts with low sugar content (LowSC) and gluconic acid in hosts with high sugar content (HighSC), respectively, as a mechanism to modulate enhanced pathogenicity. We studied the pathogens interactions with tomato lines of similar genetic background but differing in their sugar content. Colletotrichum gloeosporioides showed enhanced colonization of the LowSC line with differential expression response of 15% of its genes including enhanced relative expression of glycosyl hydrolases, glucanase and MFS-transporter genes. Enhanced colonization of P. expansum occurred in the HighSC line, accompanied by an increase in carbohydrate metabolic processes mainly phosphoenolpyruvate carboxykinase, and only 4% of differentially expressed genes. Gene response of the two host lines strongly differed depending on the sugar level. Limited colonization of HighSC line by C. gloeosporioides was accompanied by a marked alteration of gene expression compared the LowSC response to the same pathogen; while colonization by P. expansum resulted in a similar response of the two different hosts. We suggest that this differential pattern of fungal/host responses may be the basis for the differential of host range of both pathogens in nature. 相似文献
449.
Escherichia coli B, Escherichia coli MRE 600, Escherichia coli K 12-3300, Pseudomonas fluorescens, and Aerobacter aerogenes were grown exponentially in a bench-scale fermentor to cell concentrations in the range of 20 to 41 g dry cells/liter at 30°C and 30 to 55 g dry cells/liter at 25°C. The high cell concentrations were achieved in a growth system previously described for growth of Escherichia coli W (Biotechnol. Bioeng., 16 , 933 (1974); ibid. 17 , 227 (1975)). Various enzyme activity levels in the high-concentration cells were compared to those in cells grown in conventional low-density cultures. No significant differences were found. The culture supernatants were found to be essentially free of high-molecular weight metabolic or cell lysis products. Yield constants for glucose, nitrogen, oxygen, and phosphorus were also determined in the dense cultures and some of their relations to the growth conditions are discussed. 相似文献
450.