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Phytonematodes use a stylet and secreted effectors to modify host cells and ingest nutrients to support their growth and development. The molecular function of nematode effectors is currently the subject of intense investigation. In this review, we summarize our current understanding of nematode effectors, with a particular focus on proteinaceous stylet-secreted effectors of sedentary endoparasitic phytonematodes, for which a wealth of information has surfaced in the past 10 yr.Weprovide an update on the effector repertoires of several of the most economically important genera of phytonematodes and discuss current approaches to dissecting their function. Lastly, we highlight the latest breakthroughs in effector discovery that promise to shed new light on effector diversity and function across the phylum Nematoda.

Hundreds of species of plant viruses, many of them economically important, are transmitted by noncirculative vector transmission (acquisition by attachment of virions to vector mouthparts and inoculation by subsequent release), but virus receptors within the vector remain elusive. Here we report evidence for the existence, precise location, and chemical nature of the first receptor for a noncirculative virus, cauliflower mosaic virus, in its insect vector. Electron microscopy revealed virus-like particles in a previously undescribed anatomical zone at the extreme tip of the aphid maxillary stylets. A novel in vitro interaction assay characterized binding of cauliflower mosaic virus protein P2 (which mediates virus-vector interaction) to dissected aphid stylets. A P2-GFP fusion exclusively labeled a tiny cuticular domain located in the bottom-bed of the common food/salivary duct. No binding to stylets of a non-vector species was observed, and a point mutation abolishing P2 transmission activity correlated with impaired stylet binding. The novel receptor appears to be a nonglycosylated protein deeply embedded in the chitin matrix. Insight into such insect receptor molecules will begin to open the major black box of this scientific field and might lead to new strategies to combat viral spread.

Sexual dimorphism in feeding stylets is recorded among some Phlaeothripinae that have maxillary stylets long and close together in females but wider apart in males. These atypical long feeding stylets have been found in two new species of Haplothrips from China, both taken on Artemisia from Plateau zone. Two species are described and illustrated: H. helanshanensis sp. nov. from Helanshan Mountain and H. longistylus sp. nov. from Tibet. There is no evidence of any association between feeding behaviors and feeding stylet orientation.

In 2022, the American Society of Anaesthesiologists (ASA) included indirect video laryngoscopy in their difficult airway algorithm to aid in difficult intubation. To determine the potential advantages of routinely using video laryngoscopy (VL) in nonchallenging cases, we conducted a study to examine its effects on hemodynamics, intubation time and fasting blood sugar (FBS) in comparison with direct laryngoscopy (DL). This was a double blinded, prospective, randomized, controlled trial in a university hospital included ASA I to II patients undergoing elective surgery. Patients were randomly assigned to either DL or VL with an endotracheal tube preshaped to the blade through a stylet. The primary outcome was the difference in the mean blood pressure (MBP) post intubation. Secondary outcomes included intubation time, Cormack–Lehane grade, FBS levels and other hemodynamic differences. The study was registered at (pactr.samrc.ac.za), number PACTR202305589924304. 80 patients were enrolled and intubated with either DL (n = 40) or VL (n = 40), MBP, HR, DBP, intubation time and Cormack–Lehane grade were significantly better with indirect video laryngoscopy with pre-shaped stylet than with direct laryngoscopy, with mean values of 78.83 vs 90.50 mmhg, 84.78 vs 92.13, 78.83 vs 90.50 mmhg, 15.63 vs 17.28 s respectively, but the effects of direct laryngoscopy on FBS, SBP, and saturation were not significantly different. Indirect video laryngoscopy is superior to direct laryngoscopy regarding patient's hemodynamics specially the MBP, intubation time with no significant difference regarding FBS. •Stylet use cuts intubation time & hemodynamic stress with video laryngoscope.•Preshaped stylet shortens intubation and reduces stress responses.•Faster, smoother intubation with stylet-matched video laryngoscope.•Improved hemodynamics using preshaped stylet in video laryngoscopy.•Less stress, faster intubation with blade-matched stylet technique.

The whiteflies of the Bemisia tabaci (Genn.) complex (Hemiptera: Aleyrodidae) are serious agricultural pests that cause severe losses to vegetable, ornamental and fiber crops, including potato plants, mainly as a vector of economically important viruses. Among the most important viruses affecting potato is tomato chlorosis virus (ToCV) ( Closteroviridae : Crinivirus ), which is semi-persistently transmitted by whiteflies of the genera Bemisia and Trialeurodes . Chemical control is the main method used to manage B. tabaci and ToCV; however, this whitefly is resistant to most commercially available insecticides, and some products may not effectively prevent the vector stylet activities associated with virus transmission. The effective management of B. tabaci is crucial to reduce the spread of vector-borne diseases, and to minimize economic losses. We evaluated the effects of the foliar spraying with the systemic insecticides acetamiprid, flupyradifurone and cyantraniliprole on the probing behavior of non-viruliferous and ToCV-viruliferous B. tabaci MEAM1 and ToCV transmission in potato plants. To evaluate ToCV transmission in greenhouse conditions, viruliferous whiteflies were released on potato plants at different time points (3, 24 and 72 h and 7 days) after insecticide spraying. The EPG assay showed that at 3 h after insecticide application, the probing behavior differed, depending mainly on the state of the insects (viruliferous or not), whereas 72 h after application, the probing behavior differed only on plants treated with acetamiprid and flupyradifurone, for both viruliferous and non-viruliferous whiteflies. ToCV transmission was reduced mainly in plants treated with flupyradifurone and acetamiprid, likely as a result of phloem activity disruption.

PurposeThe effect of the routine use of a stylet during tracheal intubation on first-attempt intubation success is unclear. We hypothesised that the first-attempt intubation success rate would be higher with tracheal tube + stylet than with tracheal tube alone.MethodsIn this multicentre randomised controlled trial, conducted in 32 intensive care units, we randomly assigned patients to tracheal tube + stylet or tracheal tube alone (i.e. without stylet). The primary outcome was the proportion of patients with first-attempt intubation success. The secondary outcome was the proportion of patients with complications related to tracheal intubation. Serious adverse events, i.e., traumatic injuries related to tracheal intubation, were evaluated.ResultsA total of 999 patients were included in the modified intention-to-treat analysis: 501 (50%) to tracheal tube + stylet and 498 (50%) to tracheal tube alone. First-attempt intubation success occurred in 392 patients (78.2%) in the tracheal tube + stylet group and in 356 (71.5%) in the tracheal tube alone group (absolute risk difference, 6.7; 95%CI 1.4–12.1; relative risk, 1.10; 95%CI 1.02–1.18; P = 0.01). A total of 194 patients (38.7%) in the tracheal tube + stylet group had complications related to tracheal intubation, as compared with 200 patients (40.2%) in the tracheal tube alone group (absolute risk difference, − 1.5; 95%CI − 7.5 to 4.6; relative risk, 0.96; 95%CI 0.83–1.12; P = 0.64). The incidence of serious adverse events was 4.0% and 3.6%, respectively (absolute risk difference, 0.4; 95%CI, − 2.0 to 2.8; relative risk, 1.10; 95%CI 0.59–2.06. P = 0.76).ConclusionsAmong critically ill adults undergoing tracheal intubation, using a stylet improves first-attempt intubation success.

Mouthpart structures were observed in three species of Asopinae using scanning electron microscopy to investigate their morphological disparity. The examined species attack mainly slow-moving, soft-bodied insects, primarily larval forms of the Lepidoptera, and are the natural enemies of many pests. This is the first detailed description of their external mouthparts. The triangular and elongated labrum and four-segmented tube-like labium are longer in Picromerus species (Picromerus bidens (Linnaeus, 1758) and Picromerus lewisi Scott, 1874 than in Cazira bhoutanica Schouteden, 1907. The labrum of P. lewisi and C. bhoutanica appear to be equipped with olfactory sensilla basiconica Sb3, a special type of sensilla with nanopores. The labium surface in all studied species bears 14 types of sensilla (St1–St4, Sb1–7, Sst, Sca1–2). A new characteristic of sensilla trichodea is represented in sensillum St1; in both Picromerus species, it is classified as an olfactory sensillum with nanopores. The tripartite apex of the labium consists of two lateral lobes and a central membranous lobe having microtrichial extensions. Each lobe has one sensory field, including sensilla basiconica (Sb7), sensilla styloconica (Sst), and sensilla trichodea (St4). In the three studied predatory stink bugs, each mandibular stylet tip has five irregular teeth and three long, pointed hooks. The two opposing maxillae, which are held together by a tongue-and-groove system, form a food canal and a salivary canal. The apices of the right maxilla have small teeth and few short barbs along the edge of the food canal. In P. bidens and P. lewisi, there are 5 teeth, while in C. bhoutanica there are 2. Based on structural differences, we inferred that the hook-shaped mandibular teeth, right maxilla with small teeth, and few short barbs along edge of the food canal are more adapted for a predatory lifestyle. Predatory stink bugs use sharp recurved hooks and irregular teeth penetrating, tearing, or filing devices that aid in the mechanical disruption of host tissue. Stiff bristles in the food canal may indicate their possible adaptation to feeding on insect larvae. The evolution of mouthpart morphology and the putative functional significance of sensilla are discussed, providing insight into the sensory mechanism.

The flavone luteolin and the flavonol quercetin naturally occur in plants, providing some resistance against herbivores. However, despite suggesting the potential use of these compounds for plant protection, research on their relationship with aphids is limited. The aim of our study was to assess the effect of applying two flavonoids, quercetin and luteolin, at different concentrations, in vitro on the feeding behavior of the black bean aphid Aphis fabae Scopoli (Hemiptera: Aphididae). In most events associated with stylet activity, differences in probing behavior did not vary between the control gel and those with flavonoids. Higher concentrations of quercetin increased the number of penetrations, while lower concentrations of luteolin prolonged the first probing. The addition of flavonoids to the gels reduced passive ingestion. At a concentration of 0.1%, luteolin completely stopped salivation, and at 0.01%, it shortened the average duration of this activity. In events associated with active ingestion, differences in feeding behavior were observed between the control gel and those with quercetin at lower concentrations, affecting the time to the first stylet activity and the average time of active ingestion. Lower concentrations of luteolin prolonged the time to the first active ingestion, the duration of the first active ingestion, and the average time of this activity. Increased concentrations of quercetin and luteolin negatively affected aphid feeding behavior. Quercetin was better tolerated by A. fabae. A more noticeable effect was observed with an increase in luteolin concentration on the feeding behavior of A. fabae. These findings could be applied in biotechnological projects aiming to develop plants resistant to aphids and other herbivores.

Plants propagate electrical signals in response to artificial wounding. However, little is known about the electrophysiological responses of the phloem to wounding, and whether natural damaging stimuli induce propagating electrical signals in this tissue. Here, we used living aphids and the direct current (DC) version of the electrical penetration graph (EPG) to detect changes in the membrane potential of Arabidopsis sieve elements (SEs) during caterpillar wounding. Feeding wounds in the lamina induced fast depolarization waves in the affected leaf, rising to maximum amplitude (c. 60 mV) within 2 s. Major damage to the midvein induced fast and slow depolarization waves in unwounded neighbor leaves, but only slow depolarization waves in non‐neighbor leaves. The slow depolarization waves rose to maximum amplitude (c. 30 mV) within 14 s. Expression of a jasmonate‐responsive gene was detected in leaves in which SEs displayed fast depolarization waves. No electrical signals were detected in SEs of unwounded neighbor leaves of plants with suppressed expression of GLR3.3 and GLR3.6. EPG applied as a novel approach to plant electrophysiology allows cell‐specific, robust, real‐time monitoring of early electrophysiological responses in plant cells to damage, and is potentially applicable to a broad range of plant–herbivore interactions.

The ultrastructure and development of new stylets was studied in pre-molting first instar nymph of Diaphorina citri Kuwayama (Hemiptera: Liviidae). Two oval-shaped masses of cuboidal hypodermal cells, located in the cephalic region, had long extensions that ended with developing pairs of mandibular and maxillary stylets, apparently coiled around these masses. A new structure, probably composed of softer cuticle, was found on the ventral side of each developing stylet suggesting that this structure may work as a mold during formation of the new stylets. Other organs of 1st instar nymphs, including the filter chamber and bacteriome, are also ultrastructurally described.