Adhesion of lymphoid cell lines to fibronectin-coated substratum: Biochemical and physiological characterization and the identification of a 140-kDa fibronectin receptor

Little information is available on the interaction between lymphocytes and fibronectin (fn). To gain a better understanding on this issue we examined the adhesion of 12 lymphoid cell lines, each exhibiting different phenotypic characteristics, to fn-coated substratum. Of the cell lines tested, five that adhered to fn possessed B-cell characteristics, while neither the T-cell lines nor the pre-B-cell line adhered. The physiology and biochemistry of adhesion of a B-cell line, MOPC 315, were examined in detail. Our results indicated that (1) the adhesion was a specific and time-dependent process, (2) the adhesion was temperature-dependent and inhibited by metabolic inhibitors, such as KCN and 2-deoxyglucose, (3) the presence of cycloheximide and pretreatment of cells with trypsin inhibited adhesion, (4) a 140-kDa surface protein was immunoprecipitated by anti-fn receptor antibodies, (5) the presence of divalent cations was essential for adhesion, (6) the presence of colchicine had no effect on adhesion, while cytochalasin B partially inhibited adhesion, and (7) the treatment of cells by both phorbol 12-myristate 13-acetate and calcium ionophore A23187 enhanced adhesion. In this study, we have established the interaction between lymphoid cell lines and fn. Such an interaction might play an important role in the behavior of lymphocytes in tissues.     

溴氰菊酯中毒引起家蝇神经系统环腺苷酸(cAMP)含量的改变

环腺苷酸(cAMP)可在神经传递物刺激腺苷酸环化酶的作用下产生,而坏腺苷酸又可促成神经传递物的产生.用溴氰菊酯(deltamethrin)处理家蝇后,发现酪胺大量增加,主要由于酪氨酸脱羧酶受到诱导、活性增高所致.处理后一小时,cAMP也有增加,并与酶活性的增加相平行,但酪氨酸脱羧酶活性增高的曲线与cAMP量增加的曲线,实际上并不平行,因酪氨酸脱羧酶的活性是先增加,然后下降,而cAMP的量则是在开始时有一个小的下降,接着一直上升,而此时酶的诱导已下降,cAMP含量在诱导开始时出现下降的原因尚不明,可能与环鸟苷酸(cGMP)有关.但随后的上升显然是由于酪胺或章鱼胺的增加所造成.目前已证实,酪胺可经β-羟化作用形成章鱼胺,后者再刺激章鱼胺受体,而使腺苷酸环化酶活化,产生大量的cAMP.酪胺本身也可能就是章鱼胺受体的激活剂.     

玉米酯酶同工酶和过氧化物酶同工酶的分子量研究

本试验利用聚丙烯酰胺凝胶梯度电泳分步染色法直接对玉米苗期酯酶同工酶和过氧化物酶同工酶各酶带的分子量进行了比较测定。酯酶同工酶 E_1、E_2、E_3~F、E_3~S、a、b、c 各酶带的分子量分别为<20000,35200、33000、38500、29900、28500、34000道尔顿过氧化物酶同工酶 PX_4~F和 PX_4~S酶带的分子量分别为131000和149000道尔顿。根据酶带在均匀胶和梯度胶中的位置变化对各酶带的生化性质作了初步分析,发现 E_3~F和 E_3~S、PX_4~F 和 PX_4~S 在迁移率上的差异主要是分子量的差异。本文为同工酶的分子量测定提供了一个简便的方法。     

Comparison of the three-dimensional structure of two human rhinoviruses (HRV2 and HRV14)

An attempt has been made to build a model of human rhinovirus 2 (HRV2) based on the known human rhinovirus 14 (HRV14) structure. HRV2 was selected because its amino acid sequence is known and because it belongs to the minor rhinovirus receptor class as compared to HRV14, which belongs to the major class. Initial alignment of HRV2 with HRV14 based on the primary sequence and the knowledge of the three-dimensional structure of HRV14 showed that the most probable position of the majority of insertions and deletions occurred in the vicinity of the neutralizing immunogenic sites (NIm). Out of a total of 855 amino acids present in one copy of each of the capsid proteins VP1 through VP4 of HRV14, 411 are different between the two viruses. There are also 6 amino acid residues inserted and 14 residues deleted in HRV2 relative to HRV14. Examination of amino acid interactions showed several cases of conservation of function, e.g., salt bridges or the filling of restricted space. The largest variation amongst the residues lining the canyon, the putative receptor binding site, was in the carboxy-terminal residues of VP1.     

Gamma-crystallins of the human eye lens: expression analysis of five members of the gene family.

While only two gamma-crystallins have been identified in the human eye lens, molecular studies indicate that the human gamma-crystallins are encoded in a multigene family comprising at least seven closely related members. Sequence analysis of five of these genes has suggested that three (gamma 1-2, G3, and G4) are potentially active, while two (G1 psi and G2 psi) correspond to closely related pseudogenes. Here we report on the detailed structure of a sixth gamma-crystallin gene, G5, and our results obtained with transient expression assays to characterize both the promoter activity and translation products of five members of the gene family. We show that 5'-flanking sequences of G1 psi and G2 psi lacked detectable promoter activity, while the corresponding sequences of G3, G4, and G5 were able to direct high levels of expression of the bacterial chloramphenicol acetyltransferase gene in primary lens epithelia, but not in cultures of nonlens origin. Detailed sequence comparisons indicated that active genes contained several conserved sequence tracts 5' of the TATA box which may constitute functional elements of a lens-specific gamma-crystallin promoter. Expression of the gamma-crystallin coding sequences from the human metallothionein IIA promoter in nonlens cells facilitated characterization of the polypeptides encoded by individual gamma-genes and, in future studies, should permit comparison of these proteins with distinct gamma-crystallins in the human lens.     

亚洲东南部特有的新悬藓属的研究

新悬藓属现知共4种,属于蔓藓科,为亚洲东南部特有,我国是该属植物分布的中心。本文提出拟猫尾藓仍归为船叶藓科更合适。     

Decarboxylation of uroporphyrinogen III by erythrocyte uroporphyrinogen decarboxylase. Evidence for a random decarboxylation mechanism.

The isomeric composition of type-III heptacarboxylic porphyrinogens derived from decarbosylation of uroporphyrinogen III by erythrocyte uroporphyringogen decarboxylase was analysed by h.p.l.c. with electrochemical detection. All four possible isomers were identified, and there were little differences in the proportion of isomers formed by erythrocytes from normal subjects and from patients with sporadic porphyria cutanea tarda. The results provide conclusive evidence that the normal decarboxylation pathway is random in nature, and the fourth isomer only increases when enzyme abnormality is found.