Marine turf of an invasive alga expels lugworms from the lower shore

Bare sandy flats at and below low tide level of the Wadden Sea (eastern North Sea, European Atlantic) were observed in 2020 to have been invaded by an introduced grass-like alga, Vaucheria cf. velutina (Xanthophyceae). A dense algal turf accumulated and stabilized mud, where resident seniors of the lugworm Arenicola marina had reworked rippled sand. Algae and worms were incompatible. Initially, rising patches with algal turf alternated with bare pits where lugworms crowded. Their bioturbation inhibited young algae, while the felt of established algal rhizoids clogged feeding funnels of worm burrows. Eventually, a mosaic pattern of competitors gave way to a coherent algal turf without lugworms. Concomitantly, a rich small-sized benthic fauna took advantage of the novel algal turf. This exotic Vaucheria may have the potential for drastically altering the ecological web at the lower shore.

Decoding enigma: Turner syndrome with ring chromosome

ABSTRACT Ring chromosome X is one of the rarest with some unique phenotypical features in Turner syndrome. A young female presented to us with anasarca developed over the past 2 months due to congestive cardiac failure along with jaundice and orthopnea. She had growth retardation, intellectual disability, primary amenorrhea, lack of secondary sexual character development and dysmorphic features like low posterior hairline, shield chest and cubitus valgus. She had dilated cardiomyopathy (DCM) with intracardiac thrombus on echocardiography. Skeletal survey revealed short fourth metacarpal/tarsal on limbs. Karyotyping showed a mosaic pattern, with 45, X/46, X,r(X)(p22.3q28), i.e. Turner syndrome karyotype with ring chromosome. Her heart failure with reduced ejection fraction was managed with vasopressor along with anticoagulant and given oral contraceptive pills for hormone replacement therapy. The ring chromosomal pattern of karyotype in this patient and DCM is a rare cardiological phenomenon that can be associated with Turner syndrome, making this case a unique one.

CRISPR-Cas9 induces large structural variants at on-target and off-target sites in vivo that segregate across generations

To investigate the extent and distribution of unintended mutations induced by CRISPR-Cas9 in vivo, we edited the genome of fertilized zebrafish eggs and investigated DNA from >1100 larvae, juvenile and adult fish in the F0 and F1 generations. Four guide RNAs (gRNAs) were used, selected from 23 gRNAs with high on-target efficiency in vivo in previous functional experiments. CRISPR-Cas9 outcomes were analyzed by long-read sequencing of on-target sites and off-target sites detected in vitro. In founder larvae, on-target editing of the four gRNAs was 93-97% efficient, and three sites across two gRNAs were identified with in vivo off-target editing. Seven percent of the CRISPR-Cas9 editing outcomes correspond to structural variants (SVs), i.e., insertions and deletions ≥50 bp. The adult founder fish displayed a mosaic pattern of editing events in somatic and germ cells. The F1 generation contained high levels of genome editing, with all alleles of 46 examined F1 juvenile fish affected by on-target mutations, including four cases of SVs. In addition, 26% of the juvenile F1 fish (n=12) carried off-target mutations. These CRISPR-induced off-target mutations in F1 fish were successfully validated in pooled larvae from the same founder parents. In conclusion, we demonstrate that large SVs and off-target mutations can be introduced in vivo and passed through the germline to the F1 generation. The results have important consequences for the use of CRISPR-Cas9 in clinical applications, where pre-testing for off-target activity and SVs on patient material is advisable to reduce the risk of unanticipated effects with potentially large implications.

Marine Turf of an Invasive Alga Ousts Lugworms From Lower Shore

Bare sandy flats at and below low tide level were observed in 2020 to have been invaded by an introduced grass-like alga, Vaucheria cf. velutina (Xanthophyceae). A dense algal turf accumulated and stabilized mud where resident seniors of the lugworm Arenicola marina had reworked rippled sand. Algae and worms were incompatible. Initially, rising patches with algal turf alternated with bare pits where lugworms crowded. Their bioturbation inhibited young algae, while the felt of established algal rhizoids clogged feeding funnels of worm burrows. Eventually, the mosaic pattern of competitors gave way to a coherent algal turf without lugworms. Concomitantly, a rich small-sized benthic fauna took advantage of the novel algal turf. This exotic Vaucheria has the potential for taking over at the lower shore of the Wadden Sea (eastern North Sea, European Atlantic).

A Turner syndrome case associated with dic(Y;22)

Background Constitutional telomeric associations are very rare events and the mechanism underlying their development is not well understood. Case presentation We here describe a female case of Turner syndrome with a 45,X,add(22)(p11.2)[25]/45,X[5]. We reconfirmed this karyotype by FISH analysis as 45,X,dic(Y;22)(p11.3;p11.2)[28]/45,X[2].ish dic(Y;22)(SRY+,DYZ1+). A possible mechanism underlying this mosaicism was a loss of dic(Y;22) followed by a monosomy rescue of chromosome 22. However, SNP microarray analysis revealed no loss of heterozygosity (LOH) in chromosome 22, although a mosaic pattern of LOH was clearly detectable at the pseudoautosomal regions of the sex chromosomes. Conclusions Our results suggest that the separation of the dicentric chromosome at the junction resulted in a loss of chromosome Y without a loss of chromosome 22, leading to this patient’s unique mosaicism. Although telomere signals were not detected by FISH at the junction, it is likely that the original dic(Y;22) chromosome was generated by unstable telomeric associations. We propose a novel “pulled apart” mechanism as the process underlying this mosaicism.

Leprous Neuropathy: Observational Study Highlighting the Role of Electrophysiology in Early Diagnosis

Background Worldwide leprosy is a common cause of peripheral neuropathy. Electrophysiology is underutilized in its diagnosis. Objective This study aims to evaluate the usefulness of electrophysiological study in the diagnosis of leprous neuropathy. Materials and Methods Clinical and electrophysiological abnormalities of 36 histopathology proven leprosy patients from January 2015 to January 2017 were studied. Statistical Analysis Proportions were compared by Chi-square test. Results Total patients were 36. Thirty-four patients had abnormal electrophysiology and 34 had neurological deficits like weakness, sensory changes, and thickening. By clinical examination, multiple nerve involvement (motor weakness, sensory changes, and nerve thickening) occurred in 29, single nerve in 5, and no nerve involvement in 2. With electrophysiology, multiple nerve involvement (mononeuritis multiplex) was present in 32, single nerve in 2, and normal conduction parameters in 2. From the 36 patients, a total of 1,008 nerves were subjected to clinical examination and 132 were picked up clinically as affected, (13.1%). Electrophysiological study was done in 504 nerves, and 215 were found to be involved, (43%). Nerve abnormality detected by electrophysiology is significantly higher than clinical detection. (Chi-square =164.4054; p = 0.0000). Clinically, the most commonly affected nerve was unar (27) and the least affected was median (2) nerve. Electrophysiology detected 69% of nerves with demyelination and 35% of nerves with axonal features (mosaic pattern). Discussion There was subclinical neuropathy with electroclinical dissociation, as evidenced by more abnormality in electrophysiology than clinical examination. The nerve involvement was mononeuritis or mononeuritis multiplex pattern, both clinically and electrophysiologically. Electrophysiology showed both axonal and demyelinating nerve involvement (mosaic pattern). All the three features are present in leprous neuropathy. In corollary, if a patient has these electrophysiological features, he should be thoroughly investigated for leprosy. Conclusion Triple findings, such as subclinical neuropathy with electroclinical dissociation, mononeuritis multiplex, and mosaic pattern of demyelination and axonopathy, suggest leprous neuropathy

A De Novo Mosaic PHEX Variant Causing Sporadic X-Linked Hypophosphatemic Rickets in a 2-Year-Old Girl

Pathogenic variants in the PHEX gene are causative of X-linked hypophosphatemic rickets (XLH). We present a case of a 2-year-old girl with hypophosphatemic rickets with genu varum and short stature without any family history of XLH. Next generation sequencing of the PHEX gene identified a splice donor variant, NM_000444.6:c.1173 + 5G > A in intron 10. This variant had a mosaic pattern with only 22% of the sequence reads showing the variant allele and was not present in the girl's parents, both of whom had a normal phenotype. This is a sporadic case of a de novo mosaic splice-site variant in the PHEX gene.

Histochemical Distribution of Acetylcholinesterase in the Forebrain Nuclei of an Indian Non Catfish Channa punctatus

Background: Acetylcholinesterase (AChE) is an enzyme belonging to hydrolase group which splits the acetylcholine in to choline and acetate. It is supposed to be a marker of cholinergic and cholinoceptive neurons. Acetylcholinesterase histochemisry has been done in a number of vertebrates but it is still obscure and scattered in fishes, particularly in Indian fishes. Methods: In the present study a modified histochemical technique has been employed to histochemically map the acetylcholinesterase containing neurons in the telencephalic and diencephalic nuclei of C. punctatus described by Hedreen, et al (1985).Result: Acetylchoinesterase is differentially expressed in the various prosencephalic centres and nuclei of the brain, thus its staining clearly demarcates these centres and nuclei based on varying enzyme intensity. Among the pallial nuclei of the forebrain, medial and dorsolateral nuclei showed intense enzyme activity while ventral dorsolateral nucleus and central nucleus showed moderate reaction. In contrast, most of the subpallial nuclei of the forebrain showed high intensity. Diencephalic nuclei of the forebrain exhibited mosaic pattern of enzyme distribution.