Chirality is essential in nearly all biological organizations and chemical reactions but is rarely considered due to technical limitations in identifying L/D isomerization. Using OmpF, a membrane channel from Escherichia coli with an electrostatically asymmetric constriction zone, allows discriminating chiral amino acids in a single peptide. The heterogeneous distribution of charged residues in OmpF causes a strong lateral electrostatic field at the constriction. This laterally asymmetric constriction zone forces the sidechains of the peptides to specific orientations within OmpF, causing distinct ionic current fluctuations. Using statistical analysis of the respective ionic current variations allows distinguishing the presence and position of a single amino acid with different chiralities. To explore potential applications, the disease-related peptide β-Amyloid and its d‑Asp1 isoform and a mixture of the icatibant peptide drug (HOE 140) and its d‑Ser7 mutant have been discriminated. Both chiral isomers were not applicable to be distinguished by mass spectroscopy approaches. These findings highlight a novel sensing mechanism for identifying single amino acids in single peptides and even for achieving single-molecule protein sequencing.

A brief preliminary revision of the genus Scelimena Serville, 1838 (Tetrigidae: Scelimeninae: Scelimenini) from PR China is presented. Scelimena pyrroma Lao, Kasalo, Gao, Deng et Skejo sp. nov. is described from Hainan, Ding'an, based on a female holotype and a male paratype, and an additional photograph of a female in the natural habitat from Wuzhi National Nature Reserve (Wuzhi-shan Mountain). Specimens of this new species were hitherto reported from Hainan as S. dentiumeris (Hancock, 1907), a species endemic to Borneo. The new species is easily distinguished from its congeners by the presence of prominent yellow humeral tubercles and by the lateral pronotal spines directed forwards. The new species from Hainan and S. chinensis (Hancock, 1915) from Vietnam are assigned to Scelimena producta species group based on the similarity with S. producta (Serville, 1838), which is characterized by the humeral angles with tubercles, wide vertex, and toothed ventral margins of hind femora, while S. boettcheri Günther, 1938 from Palawan is assigned to Scelimena discalis species group, based on the tuberculated median carina. Scelimena dammermanni Günther, 1938, stat. nov., hitherto regarded as a subspecies of S. producta, is elevated to a species level because it lacks ventral spines on the hind legs, present in all S. producta individuals. New synonymy is established: Scelimena melli Günther, 1938, =Scelimena brevispina Cao et Zheng, 2011, syn. nov.; =Scelimena wulingshana Zheng, 1993, syn. nov.; =Eufalconoides guizhouensis Zheng et Shi, 2006, syn. nov. Scelimena melli, S. guangxiensis Zheng et Jiang, 1994 from southern China and S. kempi (Hancock, 1915) from NE India are assigned to S. bellula species group on the basis of similarity to S. bellula Storozhenko et Dawwrueng, 2015. Further research should determine whether S. spicupennis Zheng & Ou, 2003 represents a valid species or a synonym of another Scelimena species, as well as if S. nitidogranulosa Günther, 1938 and S. guangxiensis Zheng & Jiang, 1994 represent separate species or whether they are conspecific. Specimens of S. nitidogranulosa from Hainan reported by Liang & Zheng in 1998 are in fact Platygavialidium sinicum Günther, 1939. Scelimena songkrana Zha et Wen, 2017 is recorded from China for the first time. A key to Scelimena species found in PR China is also provided.

The theridiid spider genus Stemmops O. Pickard-Cambridge, 1894 includes 27 extant species and is distributed in America (23 spp.) and Asia (4 spp.). Three species, S. forcipus Zhu, 1998 (♂♀), S. nigrabdomenus Zhu, 1998 (♂) and S. nipponicus Yaginuma, 1969 (♂♀), are currently known from China. Two new species of Stemmops are described from China: S. atratus sp. n. (♀, Jiangsu, Zhejiang) and S. lini sp. n. (♂♀, Fujian, Zhejiang). In addition, the previously unknown female of S. nigrabdomenus Zhu, 1998 is described. Photos and morphological descriptions are provided.