Infrared spectroscopy of proteins

This review discusses the application of infrared spectroscopy to the study of proteins. The focus is on the mid-infrared spectral region and the study of protein reactions by reaction-induced infrared difference spectroscopy.     

The control of incompatibility in distylous Pulmonaria affinis Jordan (Boraginaceae)

In P. affinis, pin pollen is shorter on average than thrum pollen. Pins have more coronal hooks on stigmatic papillae than thrums, but gaps between papillae are relatively smaller for thrums. Pin stigmas receive more pollen than thrum stigmas. Thrum stigmas receive more (dissortive) pin pollen, but pin stigmas are assortively pollinated. Pollen only germinates when trapped below papilla coronas. On thrum stigmas, most trapped pollen is pin. Pollen germination is better on thrum stigmas than pin stigmas, and thrum stigmas show a close relationship between numbers of legitimate pollen grains, numbers of germinating grains, and numbers of pollen tubes in the style. There is no inhibition of illegitimate pollen germination. Illegitimate pollen tubes are inhibited in the style. Incompatibility operates by a combination of dissortive pollination, dissortive pollen trapping, and stylar pollen tube inhibition. All heteromorphic features differing between pins and thrums are implicated in the inhibition of within-morph fertilization in thrums.     

Regulation of the plane of cell division in vacuolated cells

Summary In small leaf explants fromNautilocalyx lynchii (Hook. f.) Sprague (Gesneriaceae) the vacuolated epidermal cells divide after 3–4 days. Most cells divide periclinally, but longitudinal and transverse divisions are also found. Before mitosis the cells form a phragmosome (PS), a cytoplasmic structure which contacts the cell cortex at the future division site. An experimental approach was used to find out at which time the plane of cell division becomes fixed: prior to or during the formation of a PS.When 3 day-old explants were divided into two parts by a longitudinal cut, a high percentage of the cells near the wound divided longitudinally. Cells which already had a PS at the time of wounding most often divided in the plane of the PS. Some of the cells with a non-longitudinal PS, however, formed a longitudinal cell wall after the replacement of the original PS by a longitudinal PS.The observations show that most cells which had not yet formed a PS could be induced to form a cell wall in a new direction. As soon as the formation of the PS had started, however, it became more difficult to induce a change in the plane of cell division. These results suggest that the division site is chosen during the formation of the PS.Abbreviations BMT band of microtubules - DIC differential interference contrast microscopy - l longitudinal - l-o longitudinal-oblique - MT microtubule - p periclinal - PM prometaphase - PPB preprophase band - PS phragmosome - t transverse - t-o transverse-oblique     

凝血-纤溶失衡与子痫前期的关系及对产后大出血的预测价值研究

摘要 目的：分析凝血-纤溶失衡与子痫前期的关系及对产后大出血的预测价值。方法：选择我院自2018年1月至2021年12月接诊的160例子痫前期孕妇作为观察组,另选同期的160例健康妊娠孕妇作为对照组;以凝血酶-抗凝血酶复合物（TAT）/纤溶酶-α2纤溶酶抑制物复合物（PIC）比值评价凝血-纤溶失衡程度,使用Pearson相关性分析TAT/PIC比值与分娩孕周、分娩出血量的关系,通过AUC评价TAT/PIC比值对产后大出血的预测效能。结果：观察组血浆TAT水平高于对照组,PIC水平低于对照组,TAT/PIC比值大于对照组（P<0.05）;经Pearson相关性分析,子痫前期孕妇TAT/PIC比值与分娩出血量呈正相关,与出生体重呈负相关（P<0.05）;产后大出血组血浆TAT水平高于非产后大出血组,PIC水平低于非产后大出血组,TAT/PIC比值大于非产后大出血组（P<0.05）;经ROC曲线分析,TAT/PIC比值预测子痫前期孕妇产后大出血的AUC为0.910,大于TAT的0.665和PIC的0.650（P<0.05）。结论：子痫前期的发生可能与凝血-纤溶失衡有关,而TAT/PIC比值与分娩出血量及出生体重的关系密切,预测产后大出血的效能较好,值得临床予以重视应用。     

慢性牙周炎患者血清CGRP、PGE2、CCL20与牙周临床指标和Th17/Treg失衡的相关性分析

摘要 目的：探究慢性牙周炎患者血清降钙素基因相关肽（CGRP）、前列腺素E₂（PGE₂）、CC趋化因子配体20（CCL20）与牙周临床指标和辅助性T淋巴细胞17/调节性T淋巴细胞（Th17/Treg）失衡的相关性。方法：选取2020年5月-2022年5月海南省妇女儿童医学中心收治的91例慢性牙周炎患者,根据其严重程度分为轻度组（39例）、中度组（36例）、重度组（16例）,比较三组血清CGRP、PGE₂、CCL20、牙周临床指标[出血指数（BI）、探诊深度（PD）、附着丧失（AL）、菌斑指数（PLI）]、外周血Th17细胞比例、Treg细胞比例、Th17/Treg比值,采用Pearson相关分析血清CGRP、PGE₂、CCL20与牙周临床指标和Th17/Treg失衡的相关性。结果：与轻度组比较,中度组、重度组血清CGRP、Treg细胞比例显著降低（P＜0.05）,血清PGE₂、CCL20、BI、PD、PLI、AL、Th17细胞比例、Th17/Treg比值显著增高（P＜0.05）;与中度组比较,重度组血清CGRP、Treg细胞比例显著降低（P＜0.05）,血清PGE₂、CCL20、BI、PD、PLI、AL、Th17细胞比例、Th17/Treg比值显著增高（P＜0.05）。相关性结果提示,血清PGE₂、CCL20水平与BI、PD、PLI、AL、Th17细胞比例、Th17/Treg比值呈正相关（P＜0.05）,与Treg细胞比例呈负相关（P＜0.05）;血清CGRP水平与BI、PD、PLI、AL、Th17细胞比例、Th17/Treg比值呈负相关（P＜0.05）,与Treg细胞比例呈正相关（P＜0.05）。结论：慢性牙周炎患者血清CGRP、PGE₂、CCL20水平与疾病严重程度、牙周临床指标及Th17/Treg失衡显著相关,血清CGRP、PGE₂、CCL20可能通过影响Th17/Treg平衡参与慢性牙周炎的发生和发展。     

抗胃酸分泌药物对胃内菌群的影响

收集４０例内镜确诊为胃十二指肠溃疡病人,随机分成两组,分别予泰胃美、奥美拉唑口服;干服药前后分别行胃镜检查,并抽吸胃液行需氧菌、厌氧菌及真菌培养。结果示：胃液细菌量及硝酸盐还原菌量与胃液ｐＨ值呈正相关（ｒ＝０．８０２和０．７,ｐ＜０．０１）,抗胃酸分泌药物尤以奥美拉唑引起胃内菌量增加明显。临床治疗消化性溃疡时,应注意胃内微生态防治。     

Cytotaxonomy and breeding system of the genusBiscutella (Cruciferae)

Chromosome counts were determined for 46 populations ofBiscutella representing 28 taxa. The genus was found to contain diploid taxa with 2n = 12, 16 and 18, tetraploid taxa with 2n = 36 and hexaploid taxa having 2n = 54.B. laevigata L. s. l. consists of diploid and tetraploid populations which are poorly differentiated morphologically. TetraploidB. laevigata s. l. and hexaploidB. variegata Boiss. & Reuter (s. l.) are characterized by chromosomal instability. The variation in chromosome numbers and the occurrence of polyploidy is discussed in relation to the taxonomy of the genus. An investigation of the breeding system showed that most of the annual species were self-compatible and partly inbreeding and most of the perennial species self-incompatible and, therefore, outbreeding, while one annual species,B. cichoriifolia Loisel., showed both systems.     

The natural history of the helicoidal occlusal plane and its evolution in early Homo

In modern man the pitch of the occlusal plane may vary along the tooth-row. When anterior cheek-teeth show a plane sloping upward palatally, whilst that on posterior cheek-teeth slopes upward buccally, there results a twisted or helicoidal occlusal plane (Ackermann). Several hypotheses have been proposed for the structural basis of the helicoidal occlusal plane. Campbell's proposal ('25) has gained widest acceptance, namely that the helicoid results from anteroposterior differences in upper and lower alveolar arch width. In the early 1960s, while studying the Olduvai hominids assigned to Homo habilis, the author noted changing occlusal slopes along the tooth-row and a slight helicoid, although these featues had not been noted in other early hominids. Subsequently, Wallace showed a total absence of the helicoid from South African australopithecines, and its presence in Swartkrans Homo, SK 45 and SK 80. Recent studies confirm the presence of the helicoid in all available specimens of H. habilis, including Stw 53 found at Sterkfontein in 1976. Hence, this trait may distinguish between Australopithecus and early Homo. Measurements of the maxillary arch widths have shown that, whereas in Australopithecus arch widths increase to a maximum at M3, in early Homo maxillary arch widths are greatest at M2. The decline in posterior maxillary arch width is part of a general reduction of that region. Thus despite striking elongation of premolars and M1 in early Homo, M2 and M3 are mesiodistally abbreviated. It is hypothesized that the onset of posterior arch reduction, with the appearance of a helicoid, was a structural and functional concomitant of the transition from the presumed australopithecine ancestor to H. habilis.     

Synthesis and degradation of proteins during wheat endosperm development

Synthesis of proteins rich in lysine declines progressively with endosperm development and these proteins appear to be degraded preferentially at later stages. The proteolytic enzymes in extracts of endosperms at a late stage of development release considerably more lysine radioactivity from labelled endosperm proteins as compared with the enzymes in endosperms at an early stage.